Buku Profile Publikasi Penelitian FINAL

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DAFTAR ISI SAMBUTAN DEKAN FTUI................................................................................................................................................................................ 5 Data Publikasi..................................................................................................................................................................................................... 6 Selected International Publication................................................................................................................................................................... 9 Anti-Inflammatory Activity of Tetragronula Species From Indonesia......................................................................................................... 10 Enhancing Battery Performance by Nano Si Addition to Li4Ti5O12 as Anode Material on Lithium-ion Battery................................ 12 Improving Weld Penetration by Employing of Magnetic Poles’ Configurations to an Autogenous Tungsten Inert Gas (TIG) Welding..................................................................................................................................................................................... 14 Simultaneous Etching and Transfer – Free Multilayer Graphene Sheets Derived from C60 Thin Films................................................... 16 What Changes After Switching to 4G-LTE? Findings From The Indonesian Market................................................................................. 18 Proposal for Improving White-Space Channel Availability........................................................................................................................... 20 Hot Water Temperature Prediction Using a Dynamic Neural Network for Absorption Chiller Application in Indonesia......................................................................................................................................................................................................... 22 Experimental Investigation of The Operating Characteristics of a Hybrid Loop Heat Pipe Using Pump Assistance........................... 24 Segregation and Gentrification of an Informal Settlement in a City Center.............................................................................................. 26 Nanostructural Growth Investigation of ZnO Nanorods Derived from Chemical Bath Deposition for Transparent Heater Application.......................................................................................................................................................................................................... 28 Developing A Conceptual Design of Transit-Oriented Development to Improve Urban Land Use Planning........................................ 30 Antiviral Activity of Acanthaster planci Phospholipase A2 Against Auman Immunodeficiency Virus................................................... 32 Nanostructure Properties and Dye-Sensitized-Solar-Cell Open Circuit Voltage of A TiO2 Aerogel and Pre-Hydrothermally Treated Xerogel................................................................................................................................................................................................... 34 High-Performance Radiation Design of a Planar Bow-Tie Antenna Combined with a Dielectric Lens and Cascaded Matching Layers at Terahertz Frequencies....................................................................................................................................................................... 36 Living Material as a Building Façade: The Effect of Moss Growth toward Mechanical Performance on Pre-vegetated Concrete.... 38 Effect of Cooling Rate and Neodymium Addition on Beta Intermetallic Phase of Al-Fe-Si Ternary System.......................................... 40 Effect of Coating Layer of Sand Casting Mold in Thin-Walled Ductile Iron Casting: Reducing the Skin Effect Formation................. 42 Performance Test of 2.5 kW DC Boost Converter for Nanogrid System Applications.............................................................................. 44 Anti-amoebic activity of acyclic and cyclic-samarium complexes on Acanthamoeba............................................................................. 46 Production of Dry Extract Lipase from Pseudomonas Aeruginosa by The Submerged Fermentation Method in Palm Oil Mill Effluent......................................................................................................................................................................................................... 48 Deacidification of palm oil using betaine monohydrate-based natural deep eutectic solvents............................................................. 50 Evaluation of Separate and Simultaneous Kinetic Parameters for Levulinic Acid and Furfural Production from Pretreated Palm Oil Empty Fruit Bunches.................................................................................................................................................................................... 52 Visible Light Absorption and Photo-Sensitizing Characteristics of Natural Dye Extracted from Mangosteen Pericarps Using Different Solvents.................................................................................................................................................................................... 54 Optimization of Random Access Channel in NB-IoT...................................................................................................................................... 56 Enhanced Photocatalytic Activity of Pt Deposited on Titania Nanotube Arrays for The Hydrogen Production with Glycerol as a Sacrificial Agent.................................................................................................................................................................................................. 58 Preparation and Characterization of Phosphate-Sludge Kaolin Mixture for Ceramics Bricks................................................................ 60 The Effect Of Metal Loading On The Performance Of Tri-Metallic Supported Catalyst For Carbon Nanotubes Synthesis From Liquefied Petroleum Gas.................................................................................................................................................................................... 62 Evaluation of Spatial Layout in Health Care Waiting Areas based on Simulation of Droplet Movement Trace................................... 64 Cross-Party Collaboration to Reduce Construction Waste to Design-Build Projects............................................................................... 66 Produk Inovatif FTUI.......................................................................................................................................................................................... 69 PROTOSS – Center for Prototyping and Manufacturing.............................................................................................................................. 70 Mactiv (Masjid Activity)..................................................................................................................................................................................... 71 Mesin Pengolah Limbah Plastik menjadi Biji Plastik untuk skala Home Industry..................................................................................... 72 TaLis (Tabung Listrik).......................................................................................................................................................................................... 73 Jamu Bancar Resik Pencegah Aterosklerosis.................................................................................................................................................. 74 EnKuns Perfume & SuperSorb.......................................................................................................................................................................... 75 Inovasi Pencitraan Dasar Danau Menggunakan Kapal Kendali Otomatis (Autonomous)....................................................................... 76 Pengembangan Prototipe Alat Uji Siklus Termal Phase Change Materials (PCM) Untuk Aplikasi Penyimpan Panas......................... 77 3

Alat Peraga Sistem Bangunan Modular Sebagai Alat Bantu Perancangan Sekolah Cepat Tanggap Bencana.................................... 78 Sistem Bangunan Modular Untuk Sekolah Tanggap Bencana..................................................................................................................... 79 8 Channels Data Logger Termokopel Tipe K Berbasis Arduino.................................................................................................................... 80 Blue-EKG : Electrocardiogram berbasis Arduino dengan Fitur Bluetooth.................................................................................................. 81 Lampu Fototerapi Portable dengan Sistem Pemantulan Terfokus dan Daya Rendah ............................................................................ 82 Portable Infant Warmer..................................................................................................................................................................................... 83 InfraRed Photomodulator.................................................................................................................................................................................. 84 Inkubator Grashof Bayi Kembar (Twin Baby Incubator) ............................................................................................................................. 85 Inkubator Grashof Portabel (Completly Built-Up / CBU-Type) ................................................................................................................. 86 Inkubator Grashof Portabel (Completely Knock Down / CKD-Type) ........................................................................................................ 87 Low Cost Mini Patient Health Monitor .......................................................................................................................................................... 88 Alat Pemadam Api Serbaguna (MultiPurpose Fire Extenguisher)............................................................................................................... 89 Alat Penyedot Dan Penghancur Jentik Nyamuk Portabel (Portable Mosquito Larvae Vacuum and Crusher)...................................... 90 ASBUTON (Aspal dari Batuan Mineral Pulau Buton).................................................................................................................................... 91 Asbuton (Asphalt from Buton Island Mineral Rock)...................................................................................................................................... 91 BIONICO (Gel Herbal Pelembab Kulit untuk Gaya Hidup Aktif)................................................................................................................. 92 Bionico (Herbal Gel Skin Moisturizer for Active Lifestyle)............................................................................................................................. 92 BIOPESTISIDA GOGO (Pestisida Alami Ramah Lingkungan Berbahan Dasar Tembakau)...................................................................... 93 Electronic Speed Controller Berbasis AI.......................................................................................................................................................... 94 FLOLIS (Zat Topikal untuk Karies Aktif Berbahan Dasar Propolis dan Fluoride)....................................................................................... 95 FROSIMA (Inovasi Olahan Daging Bebek dengan Teknologi Restrukturisasi)........................................................................................... 96 HYDRO – ZYME................................................................................................................................................................................................. 97 Kalkulator Pengukur Laju Korosi Karbon Dioksida........................................................................................................................................ 98 Kapal Tanpa Awak.............................................................................................................................................................................................. 99 Kotak Pembawa Dan Pendingin Vaksin Portabel Hemat Energi................................................................................................................. 100 Lampu-ind: Automated and Portable Street Light Using Solar Cell Technology........................................................................................ 101 Kotak Pendingin Serbaguna Bagi Pengendara Motor................................................................................................................................... 102 Makara Adventure (Jasa Pelatihan, Sertifikasi, dan Perjalanan Wisata Bahari & Penyelaman)............................................................. 103 Melipolis (Propolis dengan Tingkat Kemurnian Tinggi Bebas Kandungan Lilin)........................................................................................ 104 Model Skala Pesawat Terbang Tanpa Awak Modular.................................................................................................................................... 105 Multigreens (Lampu Hias Multifungsi Berbasis Teknologi Nanokomposit)................................................................................................ 106 OMG-SSG (Operation Management & Serious Simulation Games)............................................................................................................ 107 Orthodontic Bracket (Khusus Orang Indonesia)............................................................................................................................................ 108 Pendingin Ruangan Berbasis Tenaga Panas Matahari.................................................................................................................................. 109 SEMEN GEOPOLIMER (Beton Cepat Kering Berbahan Limbah Industri).................................................................................................. 110 Seribudapur.com................................................................................................................................................................................................. 111 SI BESAR (Reaktor Biogas Kering).................................................................................................................................................................... 112 Sistem Pembangkit Listrik Tenaga Angin........................................................................................................................................................ 113 Toilet Portabel..................................................................................................................................................................................................... 114 Portable Toilet..................................................................................................................................................................................................... 114 4

SAMBUTAN DEKAN FTUI Fakultas Teknik Faculty of Engineering Universitas Indonesia (FTUI) is an Universitas Indonesia academic institution which always an active (FTUI) adalah sebuah role in researcg activities and community services institusi akademik yang dedicated to the solution of the problems existing in selalu mengambil society and evironment, both at national and global peran aktif dalam level. In the course of its history, researchers and kegiatan-kegiatan students at FTUI have achieved a milestone. penelitian dan pengab- Among the tangible evidence of the active role of the dian masyarakat yang faculty researchers and students are the innovative didedikasikan bagi products resulted that need to be further promoted for penyelesaian masalah-masalah yang ada di masyar- the benefits of society. As one of the measure we akat dan lingkungan, baik pada tingkat nasional present the realization of FTUI Innovative Products maupun global. Dalam perjalanan sejarahnya, para Book: “Karya Anak Bangsa untuk Negeri Tercinta” peneliti dan mahasiswa FTUI telah menorehkan with the aim that the academic community in the prestasi-prestasi yang patut dibanggakan. Faculty of Engineering Universitas Indonesia will be Diantara bukti nyata peran aktif para dosen peneliti more highly motivated to continue to work even bettter. dan mahasiswa adalah produk-produk inovatif As for general public, government, and industry, hasil penelitian yang perlu dipromosikan lebih jauh the presence of the book is expected to provide the agar dapat dimanfaatkan oleh masyarakat. necessary information related ti the proposed Sebagai salah satu langkah realisasi maka kami independence of Indonesian people to be able to menyajikan Buku Produk Inovatif FTUI: “Karya Anak produce important goods for their own country. Bangsa untuk Negeri Tercinta” dengan tujuan agar Finally, let us together pray that all this hard work will para civitas akademika di FTUI termotivasi lebih get the blessing of Allah SWT and the Faculty of lanjut untuk terus berkarya lebih baik lagi. Sedangkan Engineering Universitas Indonesia would always be bagi masyarakat umum, pemerintah dan kalangan consistent in the work to provide a model for the industri maka kehadiran buku ini diharapkan mampu environmental around. Aamiin. memberikan informasi yang dibutuhkan terkait dengan rencana kemadirian bangsa Indonesia untuk bisa memproduksi barang-barang strategis di dalam negeri sendiri. 5

Data Publikasi International Publication 2014-2019 International Publication Indexed By Scopus in 2019 Source: https://scholar.ui.ac.id (21 Januari 2020) 6

Scopus Indexed Paper and Citation Scopus Indexed Paper and Citation by Department Source: https://scholar.ui.ac.id (21 Januari 2020) 7

Citations Number per Staff Distribution of Published Journals Source: https://scholar.ui.ac.id (21 Januari 2020)

Selected International Publication

Anti-Inflammatory Activity of Tetragronula Species From Indonesia Muhamad Sahlan Andrea Devina, Diah Kartika Pratami, Herbert Situmorang, Siti Farida, Abdul Munim, Benyamin Kusumoputro, Masafumi Yohda, Ahmad Faried, Misri Gozan, Mia Ledyawati Department of Chemical Engineering Published in: Methodology Saudi Journal of Biological Sciences SJR : 0.758 Q1(2017) In Indonesia, investigations of the anti-inflammatory effects H index : 27 of propolis, particularly the identification of anti-inflamma- IF : 3.138 tory biomarkers in propolis, are limited. Therefore, in this study, we investigated the anti-inflammatory properties of Abstract Indonesian propolis. Collectively, our findings indicate that propolis may be a promising alternative to NSAIDs, with both Anti-inflammatory drugs inhibit inflammation, particularly anti-inflammatory and anti-ulcerogenic effects. those classified as nonsteroidal anti-inflammatory drugs (NSAIDs). Several studies have reported that propolis has both Propolis samples from Tetragonula sp were taken from anti-ulcerogenic and anti-inflammatory effects. In this study, Masamba, North of the Luwu district, in the South Sulawesi we investigated the bioactive compound and in vivo anti-in- Province of Indonesia. Two samples of ethanolic extracts flammatory properties of both smooth and rough propolis of propolis (EEP), consisting of soft propolis (taken from from Tetragronula sp. To further identify anti-inflammatory inside the nest) and rough propolis (taken from outside the markers in propolis, LC-MS/MS was used, and results were nest), were used as active ingredients for microencapsula- analyzed by Mass Lynx 4.1. Rough and smooth propolis of tion (5). Identification of anti-inflammatory compounds were Tetragonula sp. were microcapsulated with maltodextrin and performed using an ACQUITY UPLC I-Class System connected Arabic gum. Propolis microcapsules at dose 25–200 mg/kg through a split to a Xevo G2-XS Q-tof Mass Spectrometer were applied for carrageenan-induced rat’s paw inflammation (Waters, USA). model. Data were analyzed by one-way ANOVA and Kruskal– Wallis statistical tests. LCMS/MS experiments identified Ethical approval to conduct the study was granted by the seven anti-inflammatory compounds, including [6]-dehy- Health Research Ethics Committee, Faculty of Medicine, drogingerdione, alpha-tocopherol succinate, adhyperforin, Universitas Indonesia-Cipto Mangunkusumo Hospital (No. 6-epiangustifolin, deoxypodophyllotoxin, kurarinone, and 0350/UN.2.FI/ ETIK/2018). A total of 53 fasted adult Sprague xanthoxyletin. Our results indicated that smooth propolis Dawley rat males (200–225 g) were used in the experiments. at 50 mg/kg inhibited inflammation to the greatest extent, There were seven test groups in this study, with 6–7 animals followed by rough propolis at a dose of 25 mg/kg. SPM and in each group. To measure paw edema, the animal’s paw was RPM with the dose of 25 mg/kg had inflammatory inhibition initially measured using a plethysmometer to obtain the initial value of 62.24% and 58.12%, respectively, which is compa- paw volume. rable with the value 70.26% of sodium diclofenac with the dose of 135 mg/kg. This study suggests that propolis has the Table 1. Propolis anti-inflammatory bioactive-compound identification results potential candidate to develop as a non-steroid anti-inflam- matory drug. Bioactive Category Plant Source Chemical Structure Compounds Keywords: Anti-inflammatory; Edema; In vivo; Rough prop- olis; Soft propolis; Tetragonula sp [6]- Methoxy Ginger Dehydrogingerd phenol ione (Zingiber officinale ) alpha- Vitamin Spinach, Tocopherol sunflower, and Succinate turnip Introduction Adhyperforin Phloroglu Genus Anti-inflammatory drugs are classified as agents that either cinol Hypericum inhibit or reduce inflammation, which can occur as a result of physical injury, infection, heat, and antigen–antibody interac- 6- Diterpeno Genus Isodon tions (1). NSAIDs, including aspirin, acetaminophen, diclofenac Epiangustifolin id sodium, and ibuprofen, represent the most common type of anti-inflammatory drug. However, NSAIDs can cause addi- Deoxypodophyl Lignan Genus tional effects that are ulcerogenic (2). lotoxin Podophyllum Previous studies of Brazilian, South African, Japanese, and Kurarinone Genus Sophora Chinese propolis have shown that propolis possesses anti-in- Flavonoid flammatory effects (3,4). Recent research conducted by Paulino et al. (2015) compared the anti-inflammatory effects (legumes group) of sodium diclofenac and propolis. Both compounds demon- strated anti-inflammatory effects; however, sodium diclofenac Genus can cause ulcerogenic disease. However, additional research Xanthoxyletin Coumarin Zanthoxylum has indicated that propolis may inhibit the formation of ulcers caused by sodium diclofenac (3). and Clausena 10

Figure 1. SEM Image of spray dried propolis powder. (A) microwall Both soft and rough propolis have anti-inflammatory maltodextrin and gum arabic, (B) smooth propolis microcapsules, (C) effects. Smooth propolis exhibited higher inflammatory rough propolis microcapsules. inhibition effect than rough propolis. This result is due to the fact that soft propolis contains more isoflavones Figure 2. Rat paw. (A) Before carrageenan injection, (B) after than rough propolis. Isoflavones have antioxidant activi- carrageenan injection, (C) after propolis provisioning. ties that reduce free radicals which cause oxidative stress and inflammation. This study suggests that propolis has Result and Discussion the potential to develop as a non-steroid anti-inflamma- tory drug since our in vivo experiment showed its ability to Propolis anti-inflammatory bioactive-compound identi- decrease inflammation paw volume in Sprague Dawley Rat fication results was shown in Table 1. The morphologies induce by carrageenan. of propolis microcapsules analyzed by scanning electron microscopy (SEM) shown in Figure 1. SDP microcapsules Conclussion presented uniform spherical particles sizes ranging from 0.8 to 4 µm. The biomarkers for soft propolis that we identified in this study were [6]-dehydrogingerdione, alpha-tocopherol Figure 3. Edema volume in rat paw per each test group (SP: smooth succinate, adhyperforin, 6-epiangustifolin, deoxypodo- propolis microencapsulation, RP: rough propolis microencapsulation). phyllotoxin, and kurarinone, whereas those for rough propolis were [6]-dehydrogingerdione, alpha-tocopherol In vivo tests were performed to evaluate the anti-inflam- succinate, adhyperforin, 6-epiangustifolin, and xanthoxy- matory properties of propolis (Figure 2). Inflammation was letin. Both soft and rough propolis have anti-inflammatory induced by carrageenan, and anti-inflammatory test results effects. Smooth propolis exhibited higher inflammatory demonstrated rat paw volume changes in each test group. inhibition effect than rough propolis. This result is due The highest percentage of inflammatory inhibition was to the fact that soft propolis contains more isoflavones obtained from SPM 50, with a value of 61.81%, followed than rough propolis. Isoflavones have antioxidant activi- by RPM 25, with the value of 58.12% (Table 2). Using least ties that reduce free radicals which cause oxidative stress square method, we can calculate both SPM and RPM in the and inflammation. This study suggests that propolis has same dose; in our case we want to compare the inflamma- the potential to develop as a non-steroid anti-inflamma- tory inhibition at dose 25 mg/kg. SPM and RPM with dose tory drug since our in vivo experiment showed its ability to 25 mg/kg had inflammatory inhibition value of 62.24% and decrease inflammation paw volume in Sprague Dawley Rat 58.12%, respectively (Figure 3). induce by carrageenan. Acknowledgement We gratefully acknowledge the funding from USAID through the SHERA program - Centre for Development of Sustainable Region (CDSR). The author also acknowledges the financial support partly funded from PTUPT Project 2018 (No: 499/UN2.R3.1/HKP05.00/2018) and the World Class Professor Program (No. 123.3/D2.3/KP/2018) from the Ministry of Research, Technology and Higher Education of the Republic of Indonesia. Reference 1. Fullerton JN, Gilroy DW. Resolution of inflamma- tion: a new therapeutic frontier. Nat Rev Drug Discov. 2016;15(8):551. 2. Domiati S, El-Mallah A, Ghoneim A, Bekhit A, El Razik HA. Evaluation of anti-inflammatory, analgesic activ- ities, and side effects of some pyrazole derivatives. Inflammopharmacology. 2016;24(4):163–72. 3. Paulino N, Coutinho LA, Coutinho JR, Vilela GC, Pio V, Paulino AS. Antiulcerogenic Effect of Brazilian Propolis Formulation in Mice. Pharmacol Pharm. 2015;6:580–8. 4. Shi H, Yang H, Zhang X, Sheng Y, Huang H, Yu L. Isolation and Characterization of Five Glycerol Esters from Wuhan Propolis and Their Potential Anti-Inflammatory Properties. J Agric Food Chem. 2012;60(40):10041–7. 5. Da Silva FC, Da Fonseca CR, De Alencar et al. Assessment of production efficiency, physicochemical properties and storage stability of spray-dried prop- olis, a natural food additive, using gum Arabic and OSA starch-based carrier systems. Food Bioprod Process. 2013;91(1):28–36. 11

Enhancing Battery Performance by Nano Si Addition to Li4Ti5O12 as Anode Material on Lithium-ion Battery Anne Zulfia Syahrial Sarah Alya Firnadya, Achmad Subhan Department of Metallurgical and Materials Engineering Published in: Methodology International Journal of Ionics SJR : 0.56 Q1 (2017) The active material (LTO and nano Si), acetylene black, H index : 44 and PVDF were in Table 1. All powders was characterized IF : 2.347 by XRD, SEM link to EDX. Then made into a slurry using DMAC and stirring it using magnetic stirrer. The slurry is then placed in a Cu foil and made into battery coins inside a glove box. Finally, it was characterized CD, and CV to obtain the battery performance. Abstract Mass (gram) The lithium-ion battery is a battery that is being developed to Material Ratio LTO LTO- LTO- LTO- become a repository of energy, particularly for electric vehi- 1%Si 5%Si 10%Si cles. Lithium titanate (Li4Ti5O12) anodes are quite promising for this application because of its zero-strain properties so it LTO 80% 2 0,02 0,1 0,2 can withstand the high rate. However, the capacity of LTO Nano Si - 1,98 1,9 1,8 (Li4Ti5O12) is still relatively low. Therefore, the LTO needs to be combined with other materials that have high capacity Acetylene 10% 0,25 0,25 0,25 0,25 such as Si. Silicon has a very high capacity which is 4200 Black mAh/g, but it has a high volume of the expansion. Nano Si is 0,25 added with a variation of 1, 5, and 10%. Then, to determine PVDF 10% 0,25 0,25 0,25 the battery performance, EIS, CV, and CD are carried out. The nano Si has improved the conductivity of the anode, but Table 1. Mass composition of each sample not significantly. The addition of Si results a greater battery capacity which is 262.54 mAh/g in the LTO-10% Si. Stability Result and Discussion of composite LTO/nano Si is good, evidenced by the coulomb efficiency at the high rate of close to 100%. The result of nano Si and LTO are in Fig 1. It is seen that the nano Si tends to pile up with each other or agglomerate Keywords: Li4Ti5O12/nano Si composite, Li4Ti5O12, Nano Si, which are common problems found in nano powder. From Li-ion battery the scale bar on Fig. 1a, it is also shown that the powder is in fact nano-sized (<200nm). The morphology and distri- Introduction bution of particles of the pure LTO powder is seen to be uniform with an avarage size of 500 nm. The relatively In the automotive world, fossil fuels are the main source of small size of the LTO particle is an advantage as it increases energy to operate many vehicles, but the downside to this the surface area therefore, increasing the capacity (Fig.1b). particular fuel is the emission gas that it produces which has Images obtained by SEM with 500X magnification of the a negative effect on the earth. Because of this, electric vehi- sample LTO-1%Si, LTO-5%Si, and LTO-10%Si are shown cles (EV) and hybrid electric vehicles (HEV) have been highly in Fig. 2a, b, and c, respectively. It can be seen that the developed to reduce these emission gasses [1]. The main morphology of each anode sheet are similar, but the differ- concern is, the battery that is going to be used needs to have ence lies in the crack that is shown on each figure. The specific properties such as high capacity and good stability cracks that are shown in Fig. 2a are less visible than in Fig. to ensure long-term use and the battery needs to be able to 2b and 3c. The largest visible crack is seen in Fig.2c, which be used at a high rate (> 4C). Graphite, which is commonly has the implication that the cracks become more visible used as the anode for Lithium-Ion Battery (LIB) [2], has a with the addition of Si. good capacity which is 370 mAh/g [3,4], but graphite is not suitable to be used in EVs because pulverization can Fig. 1. Image of TEM (a) nano Si and SEM (b) LTO happen in high-rate application, so that it loses its capacity. Lithium titanate or Li4Ti5O12 (LTO), on the other hand, has an important property which is zero strain. In this study, composite is used to reduce the volume expan- sion of Si. By combining LTO and Si, the outcome that is predicted is that LTO could act as a buffer for the volume expansion of Si and Si can increase the capacity of the combined anode [5]. In this study, the combination that is used is LTO, LTO-1% Si, LTO-5% Si, and LTO-10% Si. The Si that used is nano Si which can mostly tolerate the volume change according to previous study. 12

Fig. 2. Image of SEM (a) LTO-1%Si, (b) LTO-5%Si, (c) LTO-10%Si Fig. 5 can be seen the result of CV test on the LTO sample. Two peaks appear at 1.686 and 1461 V which correspond to the insertion and extraction of Li+ ion. From the two anodic and cathodic peaks, the working voltage can be obtained by calculating the average of the two peaks which is 1.57 V that is relatively close to the theoretical working voltage of LTO which is 1.55 V. It is the same for the other samples, but the peaks that indicate the presence of Si did not show in the results. Fig. 3. XRD graph of LTO and LTO/nano Si composites Fig. 6. Graph of CD results (a) LTO, (b) LTO-1%Si, (c) LTO-5%Si, (d) The result of the XRD is seen in Fig. 3, the peaks is majority LTO-10%Si by LTO phases and S. It is proven that the mixing process of the two materials has been done well because the peaks of Fig. 6a–d, results of CD test are shown from each sample Si appear in every sample that has Si added to LTO of LTO, LTO-1% Si, LTO-5% Si, and LTO-10% Si. The results showed that the addition of Si, the capacity of the battery Fig.4. Graph of EIS results of LTO/nano Si composites becomes higher and it also remains more stable than the Fig. 4 shows the result of EIS test which is a semi-circle graph. other samples, which is shown by the plateau that is longer The value of resistivity is reverse to the value of conduc- than those with smaller amount of Si or none. It showed tivity, which means that the lower the resistivity, the higher that even though it is operated in a high-rate condition, it the conductivity. Therefore, LTO-10% Si has the highest remains stable and the capacity loss is not significant, which conductivity followed by LTO-5% Si, LTO- 1 %, and LTO. means that LTO has become a buffer to withstand the volume expansion of Si and Si has successfully contributed Fig. 5. Graph of CV results (a) LTO, (b) LTO-1%Si, (c) LTO-5%Si, (d) its capacity to the composite of LTO-Si. LTO-10%Si Conclussion • LTO-nano Si composite is successfully made by making a slurry, proven by the result of XRD. • The highest resistivity is results owned by pure LTO, followed by LTO-1% Si, LTO-5% Si, and LTO-10% Si. • The capacity indicated an increase in the value of specific capacity by adding Si. The highest capacity value was owned by LTO-10% Si that is equal to 262.54 mAh/g. Acknowledgement The author would like to thank Directorate Research and Public Services Universitas Indonesia for their financial support to do this research under HIBAH PITTA 2017 with contract no. 736/UN2.R3.1/HKP.05.00/2017. Reference 1. J. Jaguemont, L. Boulon, and Y. Dubé, Appl. Energy, vol. 164, pp. 99–114, 2016. 2. P. Verma, P. Maire, and P. Novak, Electrochim. Acta, vol. 55, no. 22, pp. 6332–6341, 2010 3. B. Scrosati and J. Garche, J. Power Sources, vol. 195, no. 9, pp. 2419–2430, 2010. 4. D. R. Tobergte and S. Curtis, Handbook of Battery Materials, vol. 53, no. 9. 2013. 5. C. Chen, R. Agrawal, and C. Wang, Nanomaterials, pp 1469–1480, 2015. 13

Improving Weld Penetration by Employing of Magnetic Poles’ Configurations to an Autogenous Tungsten Inert Gas (TIG) Welding Ario Sunar Baskoro Angga Fauzian, Haikal Basalamah, Gandjar Kiswanto, Winarto Department of Mechanical Engineering Published in: Methodology International Journal of Advanced Manufacturing Technology The materials used in this study are stainless steel 304 with a SJR : 0.994 thickness of 2 mm. The specimens are cut into a dimension of H index : 44 80 × 25 × 2 mm. The welding process used a power TIG 2200 IF : 2.347 AC/DC pulse welding machine. A static external magnetic field is generated by rectangle shape NdFeB permanent magnets Abstract with a size of 25 × 15 × 3 mm. A Gaussmeter is used to measure the magnetic induction intensity; it shows the intensity around A new configuration of permanent magnet as a source of 260 mT. The configuration of the magnetic poles is classi- external magnetic field has been established to an autoge- fied into four types which are NNNN, SSSS, NNSS, and NSNS nous tungsten inert gas (TIG) welding. The external magnetic where N is the north pole and S is the south pole. Distance field is generated by rectangle shape NdFeB permanent between magnets in all configurations is 50 mm except NNSS magnets of 260 mT and arranged in cups-type magnetic field where three types of distance are applied, which are 50, 70, and (CMF). A charge-coupled device (CCD) is applied to monitor 90 mm. the phenomenon of the arc shape. The material used in this The NNSS with distance between magnets is divided into three experiment is SS304 with a thickness of 2 mm. This study categories based on arc phenomenon, which are side deflec- aims at investigating the effect of external magnetic field tion (NNSS SD), forward deflection (NNSS FD), and backward towards the arc shape and finding the configuration, which deflection (NNSS BD). The NSNS configuration is divided into can reduce the power consumption and improve penetra- two categories which are NSNS Pull and NSNS Press. tion. A significant effect on the improvement of welding The experimental setup of TIG welding and The schematic efficiency can be achieved by using PR-NNSS-SD (50 or arrangements of external permanent magnet are arranged 70mm), PP-NNSS-SD (70 or 90 mm), or PP-NSNS-Pull (50 parallel (PR) and arranged perpendicular (PP) are shown in Fig. 1 mm). These configurations can reduce the power consump- and 2, respectively. Based on the arrangement of static perma- tion up to 11%. nent magnetic field apparatus model, it needs to establish a 2D FEM model to map the direction and distribution of magnetic Introduction field and magnitude. The main consideration is the influence of external permanent magnetic field to generate the electromag- An advanced welding technology, which introduces an netic force and changing the shape of the arc welding. external magnetic field (EMF) during the welding process, has been proposed in 1962 by Brown et al. In fact, the shape Figure 1. Schematic illustration of the experimental equipment of arc plasma is influenced by the presence of an EMF; this has been proven in many literatures [1]. In general cases, Figure 2. Schematic experimental set up of magnets arrangement: (a) EMF leads to an unbalance of the electromagnetic force permanent magnets are arranged parallel (PR) to the workpiece; (b) generated by the welding current. Hence, it causes a deflec- permanent magnets are arranged perpendicular (PP) to the workpiece. tion that is called arc blow. Previous studies using numerical approach have demonstrated that the EMF has affected the arc plasma in the process of TIG welding. As a result, the welding arc was not focused on the object and the weld penetration was reduced [2]. Since the existence of EMF has many disadvantages, in many cases, it is avoided in the welding process. However, in some cases, an EMF is applied on purpose to control the arc plasma deflection [3]. Many researchers have studied numerical approach for developing three-dimensional coupled model. Most of them are using coil to generate induction magnetic field and a few researcher attempted using permanent magnet as EMF source. Previous studies [4] found that cups-type arrangement will compress the welding arc and result in an elliptical-shaped arc model. However, they do not discuss the influence of external magnetic field towards the power efficiency. In this paper, a cups-type configuration using permanent magnet was attempting to find the best config- uration that can achieve increased power efficiency using autogenous TIG welding using DC source. 14

Figure 3. Two dimensional simulation of magnetic field density from is stretched tangential to the welding direction. Figure 4e–g side view of parallel (PR) configuration, three references cases: (a) shows the arc shape that resulted from the configuration of side view reference of the magnetic field N-N configuration; (b) N-S magnets NNSS. The effects of NNSS of the PR and PP on (or S-N) configuration; (c) S-S configuration the arc shape are almost the same, but strong deflection produced by PP. This is resulted by the permanent magnets Figure 4. The cups-type arrangement of permanent magnets, that are arranged perpendicular (PP) that was stronger than the result of the arc shape and simulation of magnetic field with parallel (PR) arrangement. The magnitude of magnetic field predicted magnetic force in all the perpendicular (PP) configuration: shows that perpendicular has 97.3 mT, while parallel has (a) NNNN; (b) SSSS; (c) NSNS-Pull; (d) NSNS-Press; (e) NNSS-SD; (f) 24.3 mT in the same spot location. Therefore, the welding NNSS-BD; (g) NNSS-FD arc is strongly deflected at perpendicular arrangement compared to the parallel arrangement. The appearance of Figure 5. Appearance of top and back bead at the configuration: (a) the top and back bead of PP-NNSS-SD and PR-NNSS-SD PP-NNSS-SD and (b) PR-NNSS-SD with I = 80 A and v = 2 mm/s configuration is shown in Fig. 5a, b. The simple comparative argument used in this paper for increasing the efficiency is Figure 6. Comparative result of bead width (a) at top and (b) back using the current comparative with matching the geometry of PR-NNSS-SD (50 and 70 mm), PP-NNSS-SD (70 or 90 mm) or of the top and back bead width. In this case, the compara- PP-NSNS-Pull (50 mm) with no magnets 80 A and 90 A tive method can only be used with a 2 mm thick stainless steel. Hence, PR-NNSS-SD, PP-NNSS-SD, or PP-NSNS- Result and Discussion Pull using 80 A have the equivalent result compared to the conventional welding of 90 A; this means that it reduces Figure 4a–g shows the predicted magnetic field and the the power consumption up to 11% and produces almost simulation of magnetic flux density from top view projec- same penetration due to the results of the back bead width. tion. Figure 4a, b shows the arc shape to have an elliptical Thereby, the power efficiency is increased further. shape than tends to bend 45° from welding line. Figure 4c shows NSNS Pull, the arc is stretched tangential to the Conclussion welding direction, while Fig. 4d shows NSNS Press, the arc The conclusions from this paper can be drawn as follows: • The PP arrangement generates a stronger magnetic field as compared to the PR arrangement. Using an external permanent magnet, the TIG welding process using 80 A can achieve the equivalent weld geometry to the conventional TIG welding using 90 A. • Using PR-NNSS-SD (50 and 70 mm), PP-NNSS-SD (70 or 90 mm), or PP-NSNS-Pull (50 mm), power consump- tion can be reduced up to 11%; therefore, with this configuration, the efficiency is increased. Therefore, PP-NNSS-SD with 90 mm distance is the best option to achieve better efficiency and minimum deflection of weld line. Acknowledgement This study was financially supported by the Directorate Research and Public Service, Universitas Indonesia through the contract number: 1753/UN2.R12/PPM.00.00/2016 with title of “Pengembangan Mesin Tungsten Inert Gas Welding Otomatis Berbasis Machine Vision dan Neural Network”. Reference 1. Wu H, Chang Y, Lu L, Bai J (2017) Review on magnet- ically controlled arc welding process. Int J Adv Manuf Technol 91(9–12): 4263–4273 2. Yin X, Gou J, Zhang J, Sun J (2012) Numerical study of arc plasmas and weld pools for GTAW with applied axial magnetic fields. J Phys D Appl Phys 45(28):285203 3. Kang YH, Na SJ (2002) A study on the modeling of magnetic arc deflection and dynamic analysis of arc sensor. Weld J (Miami, Fla) 81(1):8–13 4. Nomura K, Ogino Y, Hirata Y (2012) Shape control of TIG arc plasma by cusp-type magnetic field with permanent magnet. Weld Int 26(10):759–764 15

Simultaneous Etching and Transfer – Free Multilayer Graphene Sheets Derived from C60 Thin Films Chairul Hudaya Minjeh Ahn, Si Hyoung Oh, Bup Ju Jeon, Yung-Eun Sunge, Joong Kee Lee Department of Electrical Engineering Published in: Methodology Journal of Industrial and Engineering Chemistry The n-type Si (100) wafers with size 7cmx10cm were used SJR : Q1 as the substrates for this experiment. The substrates were H index : 60 cleaned by HF solutions for a minute to remove the inherent IF : 4.421 (SCI) native oxide layer (typically ~3nm). Here, we controlled the duration of deposition by 5, 10, and 15min to grow the Ni Abstract films with a thickness of 30, 50, and 60nm, respectively. The deposition of C60 thin films was prepared by Radio Frequency- Despite the advantage of chemical vapor deposition (CVD) Plasma Assisted Thermal Evaporation (RF-PATE) system as for realization of large area epitaxial growth of graphene schematically illustrated in Figure 1. on transition metal catalysts, both etching and transfer process of CVD-grown graphene sheets remain a big chal- The as-prepared thin films were characterized by field emis- lenge. Here we demonstrate the formation of multilayer sion scanning electron microscopy (Hitachi S-3400 FE-SEM), graphene (MLG) sheets tailored from C60 thin films on the atomic force microscopy (AFM–NanoNavi), X-ray diffraction top of Si/Ni substrate without etching and transfer steps (XRD; Rigaku RINT 2000), Raman spectroscopy (Renishaw), based on Ni films. This self-assembled process separates and X-ray photoelectron spectroscopy (XPS; PHI 5000 the MLG sheets from the conductive Ni catalyst, embarking VersaProbe). For the high-resolution transmission electron a possibility for direct characterizations of MLG sheets. The microscopy (HR-TEM; FEI Titan) analysis. fine-tuned C60 films (30 nm) are transformed into approx- imately 17 MLG sheets, thus making it large-area MLG sheets for a variety of direct applications. Keywords: Graphene C60, Thin film, Multilayer, Thermal, Evaporation Introduction Figure 1. Schematic diagram of the growth of simultaneous etching and transfer-free MLG sheets derived from C60 thin films Graphene has entrapped much interest from the scientific fields due to its extraordinary properties such as excellent Figure 2. SEM images of (a) Si/Ni/C60 (as-prepared) surface, (b) Si/Ni/ electrical and thermal conductivity, high mechanical strength, MLG (annealed) surface, and cross-sectional SEM images of (c) Si/Ni/ and high optical transmittance [1]. Due to the conduction with C60 and (d) Si/C60 without Ni layer. Note: the arrows in (a) point out metals, the as-prepared graphene layer cannot directly be char- the grain boundaries of Ni films. acterized. Hence, in order to remove the metal-catalyst from graphene layers, one must etch it with acidic solutions such as FeCl3, HCl, HNO3, and CuSO4 and subsequently transfer the graphene sheet to other sacrificial medium. Unfortunately, both etching and transfer steps, either solely or in combined role, may strongly attribute to the high contaminations, lattice defects, segregated graphene flakes, and cracks, degrading the quality of graphene sheets. In the referred studies, as C60 was deposited in the form of nanodots or nanoislands, instead of thin films, the transformed graphene layer unavoidably resulted in a small and segregated area, which is a major issue for commercialization of the graphene-based materials. One may understand the difficulty to obtain the graphene sheets from C60 thin films because many process parameters must be compromised including but not limited to the thickness of C60 thin films, the temperature and duration of annealing in the furnace, and the thickness of Ni catalyst. Thus, we demon- strated the simultaneous etching and transfer-free multilayer graphene (MLG) sheets tailored from C60 thin film via a simple modified thermal decomposition method. 16

Figure 3. a) XRD patterns and (b) Raman spectra for Si/Ni/C60 and Si/ Figure 4. (a) TEM image of cross-sectional view of Si/Ni/MLG Ni/MLG. prepared by FIB. (b) TEM-EDX analysis in respective areas at a selected area of (a). (c) HR-TEM image of MLG sheets located Result and Discussion between the SiO2 layer and epoxy film. (d) Illustration of interplanar space indicated at a selected area of (c). (For interpretation of the To fabricate the MLG sheets harvested from C60 thin films, we references to color in the text, the reader is referred to the web carried out the experiments through a modified technique. version of this article.) The deposition of C60 film was carried out by RF-PATE tech- nique. In the final step, the prepared samples were treated Conclussion at 800 °C for 15min under inert condition. The experimental details of this work are illustrated in Fig. 1. We reported an easy approach to tailor the simultaneous etching and transfer-free MLG sheets from C60 thin films The SEM images of the as-prepared samples before and after based on the RF-PATE method. The advantage of our the annealing in the tube furnace (herein after abbreviated approach is that it can create larger graphene sheets from with Si/Ni/ C60 and Si/Ni/MLG, respectively) are displayed fine-tuned C60 thin films, increase the quality of graphene in Fig. 2(a) and (b). For the Si/Ni/C60 sample, we could clearly due to avoiding the etching and transfer process, and observe the grain boundaries of Ni films on the top surface reduce the cost of production because of eliminating the of the sample. In contrast, these boundaries disappeared step of growing the SiO2 layer. Moreover, the obtained in the case of Si/Ni/MLG, possibly due to the agglomera- MLG sheets can possibly be directly employed on the tion of Ni films at high temperatures. The cross-section high materials that require high synthesis temperatures such as resolution image of the as-prepared Si/Ni/C60 (Fig. 2(c)) the cathode materials of lithium-ion batteries and optoelec- revealed the demarcation lines indicating the C60 film (~30 tronic devices. nm), Ni film (~50 nm), and suspected SiO2 layer (~15 nm). It is worth to note that except acting as a catalyst, Ni film Acknowledgement had an important role to uniformly distribute the C60 frag- ments. Without this metal catalyst, the C60 powder tended This work was supported by the International to agglomerate in the surface of the Si wafer (Fig. 2(d)). Collaborative Energy Technology R&D Program (project no. 20178530000140) of the Korea Institute of Energy The XRD pattern of Si/Ni/C60 showed a broad 20 peak at Technology Evaluation and Planning (KETEP). The authors around 20.1°, thus corresponding to the interlayer distance thank J. M. Woo and U. S. Kim for technical discussion of 4.4 Å. Some et al. identified this wide peak as a reduced during preparation of this study. C. H. was grateful with the graphene oxide (RGO) in which the peak was shifted from support of 2017 World-Class Professor Program at Faculty its original position of graphene oxide at 10.27° [2]. For the of Engineering Universitas Indonesia funded by Ministry Si/Ni/MLG sample, we found a sharp 20 peak at 21.6°, thus of Research, Technology and Higher Education, Republic being associated with the interplanar space of 4.1 Å. These of Indonesia. Y.-E. S. acknowledges that this work was values were higher than the interlayer space of graphite support by the Institute for Basic Science (IBS) in Republic (3.34 Å), which had an intense 2 0 peak commonly located of Korea (Project Code: IBS-R006-D1). at 26.71° [2]. The cross-sectional view of TEM (Fig. 4(a)) followed by energy-dispersive X-ray spectroscopy (EDX) analysis (Fig. 4(b)) at the color spots indicated in Fig. 4(a), we observed the presence of a 100-nm thick SiO2 layer on the top of the Si substrate (red), the agglomerated Ni particles with the biggest size of 50 nm (green) and the suspected MLG sheets (blue). We carefully inspected the sample with a high-reso- lution image (Fig. 4(c)). It was estimated that the number of graphene sheets was about 17 layers (~6.5-nm thick) with the average interplanar distance in the range between 3.8– 4.1 Å (Fig. 4(d)). These values were in good agreement with previous report and that obtained from our XRD analysis. Theoretically, a monolayer of C60 film can completely frag- ment to 5 graphene layers if all carbon sticks to the surface [3]. 17

What Changes After Switching to 4G-LTE? Findings From The Indonesian Market Muhammad Suryanegara Fery Andriyanto, Bagus Winarko Department of Electrical Engineering Published in: Methodology IEEE Access SJR : 0.548 We utilize the qualitative method by conducting a statis- H index : 36 tical assessment of users’ behavior over a sample of the IF : 3.557 Indonesian market population, obtained from primary data collected as part of the latest market survey in April-May Abstract 2017. An example of the quantitative approach is the work presented in [8] [9]. The profile of our sample of respon- This work identifies the market changes following the tech- dents matches relatively well with the general Indonesian nological switch from 3G to 4G in the Indonesian market. demographic profile [10] [11]. The primary data were obtained by conducting a market survey in April-May 2017. A set of questionnaires was Result and Discussion developed to compare subscribers’ activities between 3G and 4G service utilization in terms of 2 activity clusters. The The approach departs from an understanding of techno- first cluster consists of 14 conventional activities, repre- logical evolutionary theory. The term “evolution” refers to senting typical activities that have been occurring since “directional progression” in a positive direction due to the the previous implementation of mobile technology. The ‘pure objectivity’ presupposed in the world of nature [12]. second cluster consists of 11 digital ecosystem activities, The process of evolution involves processes of imperfect referring to services that also engage other technological (mistake-ridden) learning and discovery on the one hand systems through data communications. Subsequently, the and a selection mechanism on the other hand [13]. strategic implications for mobile network operators were investigated from the theoretical perspective of technolog- ical evolution. Introduction Motivated by the earlier works of Schumpeter [1,2,3], tech- nological innovation has been regarded as a stimulus for economic growth. Any progressive advancement of a tech- nology will exhibit significant mutual interactions with users of that technology, the so-called market. Such A relation- ship between technology and the market is characterized by a co-evolution mechanism, in which the technology will change along with the market [4]. Furthermore, this co-evo- lution is typified by an adaptive mechanism, allowing one to predict that continuous change will occur along with some kind of adaptation [5]. In the case of the telecommunica- tions industry, an earlier work [6] has argued that mobile wireless and the Internet have taken on an essential role in the new telecommunications era, exhibiting continuous change and co-evolution with various factors in the market system. The current work has two objectives, i.e., to identify the changing behavior of the market with the switch from 3G to 4G and to investigate the strategic implications of these changes for mobile network operators in Indonesia. As the 4th largest market in the world, Indonesia has a potential subscriber of more than 250 million, 70% of whom prefer to access the Internet through handheld mobile devices [7]. Therefore, it is important to study any relevant behavior of mobile subscribers, as they may have a significant impact on the national market. 18

Findings from the Indonesian Market Figure - The changing paradigm of service experience on 4G and its continuous technological evolution The Table lists the results of the survey and the corre- sponding percentages (taken as the maximum values). The Conclussion majority values in the table are highlighted. We have identified the market changes that occurred after Strategic Challenges for Mobile Network Operators the technological switch from 3G to 4G in the Indonesian market. The results indicate that mobile network operators First, the findings emphasize a shift from traditional calls should adaptively respond by making messenger applica- and SMS messages to multiple modes of utilization of tions the core of new service innovations. Significant traffic messenger application services. Consequently, the greatest intensification is also observed with regard to conven- challenge for network operators is how to monetize this tional activities, and there is a need for market education situation. Second, there is a trend of traffic intensifica- along with digital ecosystem establishment. The find- tion involving Internet-related activities. In Indonesia, ings also imply a changing paradigm in terms of how users the problem arises that most traffic is directed abroad, value service experience when accessing 4G applications. but there is a limitation on international bandwidth. This The overall experience is determined by interdependent situation indicates a clear need for awareness. Third, an components shaping an ecosystem perspective. The user’s ecosystem needs to be built together with market educa- handheld mobile device acts as the central gateway for tion. The message is that the market needs to be educated data communications, and its performance is assessed in to raise awareness of IoT opportunities. This opportunity relation to other connected devices and applications. encapsulates the “technology-push” phenomenon [14], providing a strong chance for alignment between product Reference and market as the target of IoT influence. 1. J.A. Schumpeter, J.A., “The Instability of Capitalism,” The New Markets Come in Unexpected Ways Economic Journal, Vol. 38, No.151, pp. 361-386, 1928. Our findings show that members of the Indonesian market 2. J.A. Schumpeter, The Theory of Economic Development, (trans. have a tendency to use their handheld devices as Wi-Fi by R. Opie from the German ed. of 1912), Cambridge MA: modems but continue to ignore health-related applications. Harvard University Press, 1934. A common global trend has suggested a new service para- digm in which users are enrolled treat handheld devices as 3. J.A. Schumpeter, Business Cycles: A Theoretical, Historical users’ gateways to a broader ecosystem, connected with and Statistical Analysis of the Capitalist Process. New York: other complex sub-systems, thereby leading to the reali- McGraw-Hill, 1939. zation of new service innovations. In service innovation, a firm will place strategic emphasis on business case develop- 4. R.R. Nelson, “The Co-evolution of Technology, Industrial ment, whereas new service development will be the firm’s Structure, and Supporting Institutions,” Industrial and focus during the implementation of such innovative proj- Corporate Change, Vol. 3, Issue 1, pp. 47-63, 1994. ects [15]. 5. B. McKelvey, “Managing Coevolutionary Dynamics,” Presented A Changing Paradigm of Service Experience at the 18th EGOS Conference, Barcelona, Spain, July 4–6, 2002. This shifting paradigm of service experience is visualized in the Figure. 6. M. Fransman, Telecoms in the Internet age: from boom to boost to? Oxford University Press, 2002. 7. APJII, “Statistic of Indonesian Internet Users,” 2016. 8. L.Jin, Y.Chen, T.Wang, P.Hui and A.V.Vasilakos, “Understanding user behavior in online social networks: a survey,” IEEE Communications Magazine, Vol.51, Issue: 9, 2013. 9. J.A. Iglesias, P.Angelov, A. Ledezma, A.Sanchis, “Creating Evolving User Behavior Profiles Automatically,” IEEE Transactions on Knowledge and Data Engineering, Vol. 24, Issue: 5, 2012. 19

Proposal for Improving White-Space Channel Availability Gunawan Wibisono Lessy Sutiyono Aji, Filbert H. Juwono, Dadang Gunawan Department of Electrical Engineering Published in: system at the receiver. PR helps to maintain or achieve the IEEE Access minimum value of the carrier-to-interference (C/I) ratio. In SJR : 0.55 Q1 (2017) practice, we use the eld strength, measured in dBuV/m, H index : 36 to calculate the coverage area of the DTT transmitter. IF : 3.557 (2017) The value of the eld strength is inuenced by the propaga- tion, transmitter antenna gain, and noise. The magnitude Abstract of the eld strength in the receiver varies according to the geographical conditions. Therefore, the PR should be able A major concern in implementing white-space technology to accommodate these variations. in a television broadcasting system is the ability of the system to provide information about the vacant chan- Methodology nels while guaranteeing protection to its primary users. Moreover, in the developing countries, the allocation of PSML Method television broadcasting channels is not as good as that in the next problem is to find how far the WSD coverage can the developed countries. Therefore, there is a high possi- t into the DTT coverage. We divide the no-talk region in bility of overlaps between the digital television terrestrial Fig. 1 into four zones, as shown in Fig 3. The first zone is coverage areas and white-space areas. Herein, we propose named the ``prohibited’’ zone, where WSD is not allowed to a method involving the use of four zones—prohibited, operate, and this level represents the DTT coverage areas strict, moderate, and loose (PSML)—to model the tele- having location probabilities above 70%. The second zone vision white-space system. We use a television coverage is called the ``strict’’ zone; at this level, we demonstrate area that has less than 70% location probability to accom- the use of the area inside the protection contour having modate the possibility of overlaps between the white a location probability below 70%. The third zone is called space and the protection areas. We also propose a protec- the ``moderate’’ zone. Moderate means that a part of the tion ratio value to complement the standard given by the area allows WSD to transmit signals with maximum power Federal Communications Committee (FCC) for countries (i.e., 4 W), while the rest of the areas do not allow this. The implementing the digital video broadcasting system (DVB- last zone is called the ``loose’’ zone, where all WSD base T2). We conduct a test to analyze the implementation of stations are allowed to use their maximum transmit power. the proposed PSML method in Bali Island, Indonesia. The We call this method the PSML method. results show that our model can provide more white-space channels than the models proposed by Villardi and the FCC Figure - PSML Method when applied to transition areas between urban and rural regions. DVB-T2 Protection Ratio Interfered by IEEE 802.22/ WSD Introduction This paper proposes the minimum PR value for DVB-T2 interfered by IEEE 802.22 WRAN with the particular speci- The development of telecommunication infrastructure in fications. In this study, we make the following settings such rural areas, especially in the developing countries. Therefore, as the transmit power of DTT is set to PDTT D 60 dBm it is desirable to provide a low-cost and easy-to-implement or 1000 W, the white-space transmitter is located at 1 km communication technology such as The Television White from the victim DTT receiver, the distance from the DTT Space (TVWS), one of the preferable technologies to provide transmitter to the DTT victim receiver was 1 km, the height communication in rural areas as it is cheap and simple to of the DTT transmitter is equal to that of the white-space implement. It does not require a dedicated spectrum allo- transmitter, that is, hDTT D hWSD D 40 m and the height cation. The TVWS technology involves the use of vacant of the DTT victim receiver is 10 m. spectrum owned by primary users for other purposes such as Internet services. The research on TVWS has become popular ever since the Federal Communications Committee (FCC) and Electronic Communications Committee (ECC) opened up opportunities to use white-space channels in 2011. As far as the white-space devices (WSDs) were located outside the no-talk region, they were allowed to operate with a maximum equivalent isotropically radiated power (EIRP) of 4 W. We note that the ECC model guaran- teed higher protection against interference. FCC and ECC standards use the protection ratio (PR). PR refers to the eld-strength ratio of the primary system to the secondary 20

Result and Discussion Figure 2. DTT no-talk region for each model. (a) TV white-space operation in co-channel. (b) TV white-space operation in the first and In this study, we perform a simulation to determine the PR second adjacent channels. for DVB-T2 when the IEEE 802.22 transmitter becomes an interferer. Protection Ratio In Table 1, we compare our PR with those proposed by FCC, OFCOM, and Ministry of Internal Affairs and Communications (MIC). Table 1. Comparison of PRs Protection Ratios (dB) Δf Proposed FCC OFCOM MIC 0 26 23 33 -10 ±1 -27 -26 -17 -29 ±2 -27 -26 -34 -29 Our proposed PR for the co-channel is 3 dB higher than Figure 3. WSD maximum transmit power. (a) TV white-space the PR of FCC. This is because we include a 5.5 dB random operation in co-channel. (b) TV white-space operation in the first and signal variation in the calculation, which causes an addi- second adjacent channels. tion of 2 dB in the margin on PR. Moreover, the masking limit value of the white space is 1 dBc higher than that of Conclussion DTT. This produces an iRSS value that is 1 dB higher, which results in a higher PR value, that is 3 dB (2 dB C 1 dB) higher We have provided an overview of the standardizations than the PR value of FCC. and recent studies related to TVWS systems. To imple- ment white-space systems, governments need to consider In Fig. 2, we show the no-talk region proposed by FCC, which both the protection to the primary users and sufcient can be used as a white space using the same channel as the white-space channels.We also have proposed a method primary user. In Figs. 7(a) and (b), the line with the diamond to overcome both concerns. First, we have proposed the mark is the no-talk region proposed by FCC, whereas the PR for DVB-T2 against IEEE 802.22 to complement the two straight horizontal lines below show the area of the FCC standard. FCC has proposed PRs for the general DTT no-talk region proposed by Villardi and the PSML model. system only. However, there are three primary DTT systems The distance between the lines with the diamond mark with different specications. We have included a variation and the straight horizontal lines increases with the antenna of 5.5 dB to accommodate the geographical changes that height, which indicates that an increasing number of areas occur in the eld. Regardless of the ratio of transmitting are categorized as white space. Both Villardi model and our power (provided that it is below the PR values), we can say model outperform the FCC model because they allow WSD that the primary user is safe from the possibility of inter- to operate within the FCC’s no-talk region. ference. Second, we have proposed the PSML method to open up more opportunities for white spaces. We have Fig. 3(b) illustrates that the limit of the transmission power used the DTT coverage area that has a location probability for white spaces tends to be looser than that shown in Fig. below 70%. Moreover, we have implemented the method 3(a). This indicates that the PSML model will show satis- using DTT transmitters and geographical contours in Bali. factory performance when WSD uses an adjacent channel. The results show more availability of white-space channels White-space transmitters may be established and operated compared with other methods. Our method has compa- within the coverage area of the TV provided that they are rable performance to the original FCC model when applied within Zone 2, and refer to the upper limit of the maximum to rural areas. Meanwhile, our algorithm is better than transmission power. other models if implemented in transition areas between the urban and rural regions.We expect that our model can be used and further developed by other regulatory bodies for their respective countries. 21

Hot Water Temperature Prediction Using a Dynamic Neural Network for Absorption Chiller Application in Indonesia Nasruddin Sholahudin, M.Idrus Alhamid, Kiyoshi Saito Department of Mechanical Engineering Published in: of H2O and LiBr are used as refrigerant and absorbent Sustainable Energy Technologies and respectively to transfer heat from a conditioned space to Assessments the ambient. There are several main components that are inter connected i.e. solar collector, hot water storage tank, SJR : 1.23 Q1 (2017) absorption chiller system, and air cooled cooling tower. Weather conditions, including ambient temperature and H index : 19 solar radiation are selected as the input of modeling. These IF : - parameters are measured using a Pyranometer. The accu- racy of prediction is measured using RMSE (root means Abstract square error) and CV (coefficient of variation) value. Weather condition particularly for solar radiation and dry Result and Discussion bulb temperature has important role in absorption chiller performance. In this paper hot water temperature predic- Correlation analysis tion in generator inlet of absorption chiller has been In simple regression analysis, the coefficient of correla- conducted under various weather conditions. Dry bulb tion can be used to analyze the relationship between temperature and global horizontal radiation are selected two variables. Table 1 indicates the coefficient of correla- as predictors. Three artificial neural network (ANN) types tion (r) between hot water and ambient temperature; solar including feed forward back-propagation, cascade forward radiation and hot water temperature. They have positive back-propagation, and Elman back propagation models correlation since r values are positive. It shows that an have been investigated for prediction. Moreover, numbers increase in in the solar radiation and ambient temperature of neuron and time delay effects were analyzed to achieve leads the hot water temperature increases. The correlation an accurate prediction. The results show that hot water between hot water and ambient temperature is stronger temperature in generator inlet can be predicted precisely than the correlation of solar radiation and hot water using a feed forward back propagation neural network with temperature. the configuration of a three hour delayed input on radiation, current dry bulb temperature, seven neurons, tan-sigmoid Table 1. Coefficient of correlation (r) transfer function and Bayesian regularization algorithm. The prediction results perform a good agreement between Time delay analysis predicted and experimental values. The error resulting Various numbers of time delay lines (TDL) have been from training and validation is 3.1 °C and 2.6 °C with a coef- analyzed using the same neural network architecture. ficient of variation at 4.4% and 3.5% respectively. Various numbers of TDL varied from 0 to 3 were applied on solar radiation input. Fig. 1 illustrates the performance Introduction of neural network training using diverse number of TDL. The application of absorption chiller is very beneficial for cooling system in tropical countries to reduce building energy consumption. This system consumes less elec- tricity than a vapor compression system because it doesn’t require a compressor to increase the refrigerant pressure to transfer heat from a low temperature to a high tempera- ture space. Consequently, the system requires a lot of heat to run the system continuously. Since a heat is the main energy source in this system, it is most appropriate to install in a tropical country e.g. Indonesia where inten- sity of solar radiation is abundant. The use of solar energy in residential buildings can save roughly 50% of primary energy. Mohanraj et al. introduced ANN model to predict the effect of solar radiation intensity on the performance of solar assisted heat pump system and demonstrate the exergy analysis. Methodology System description The system has at least two important components, namely absorbent and refrigerant [16]. The common substances 22

Figure 1. Training performance using delay (a) without delay; (b) one Conclussion hour; (c) two hours; (d) three hours. Hot water temperature prediction has been conducted using The results for training and validation as the number of TDL experimental data and several architectural ANN models increases, the accuracy tends to improve in both training including FFBP, CFBP, and EBP. Dry bulb temperature and and validation. By applying 3 TDL, the RMSE value could solar radiation were chosen as predictors where these be reduced to around 55.8% for training and 52.73% for parameters have great influence on hot water tempera- validation. tures. Correlation analysis of inputs was conducted using coefficient of correlation. It is found that the correlation Network architecture between ambient and hot water temperature is stronger than solar radiation and hot water temperature. However, Three kinds of ANN types including FFBP, CFBP, and EBP the effect of time delay on solar radiation is higher. Time models have been used for training and validation. Various delay effect of solar radiation has a great effect on predic- numbers of neurons from 1 to 11 have been tested. Table 4 tion accuracy. Dynamic ANN model with three TDL was shows the result of ANN development where RMSE value considered as the best model. Furthermore, the number of is presented to indicate the accuracy for each model. The neurons also affects the prediction accuracy greatly. As the ANN model using EBP models and 11 neurons has the number of neurons increase, the accuracy of training also lowest error in training with RMSE of 1.5 °C. However, the increases. The optimum ANN model for present study can accuracy for validation is not so good. Moreover, the ANN be performed by FFBP, 2 hidden layers, 7 neurons, and 3 model with 7 neurons shows good agreement using FFBP TDL. There is no exact rule on how to achieve high accu- and EBP models. They have the lowest error in the vali- racy in developing an ANN model. Several ANN parameters dation phase. Meanwhile, the lowest error for the CFBP including network architecture, transfer function, number model is performed using 6 neurons. The ANN configura- of neurons, hidden layer, and time delay should be deter- tion using FFBP, 7 neurons, 3 TDL and one hidden layer mined appropriately. Generally, the accuracy of prediction shows the lowest RMSE value in validation compared to in the use of ANN is highly dependent on the trend of data others with RMSE of 2.57. sets. Table 2. RMSE value of various ANN configurations. Acknowledgement This research work was supported by the Ministry of Environment of Japan and Indonesia. The authors would also like to thank all members of the refrigeration and air conditioning Lab. University of Indonesia who enabled us to conduct the research and finish this paper. Reference 1. Marc Olivier, Anies Guillaume, Lucas Franck, Castaing- Lasvignottes Jean. Assessing performance and controlling operating conditions of a solar driven absorption chiller using simplified numerical models. Sol Energy 2012;86(9):2231–9. 2. Mohanraj M, Jayaraj S, Muraleedharan C. Modeling of a direct expansion solar assisted heat pump using artificial neural networks. Int J Green Energy 2008;5:520–32. 3. Mohanraj M, Jayaraj S, Muraleedharan C. Exergy anal- ysis of direct expansion solarassisted heat pumps using artificial neural networks. Int J Energy Res 2009;33:1005–20. 23

Experimental Investigation of The Operating Characteristics of a Hybrid Loop Heat Pipe Using Pump Assistance Nandy Putra Imansyah Ibnu Hakim, Iwan Setyawan Department of Mechanical Engineering Published in: Methodology Applied Thermal Engineering In this research, an HLHP was developed by integrating a SJR : 1.5 Q1 (2017) pump with an LHP. The HLHP prototype was designed by modifying the basic LHP. The HLHP used 5-mm-diameter H index : 121 copper pipe for the vapour line and liquid line, both with IF : - a length of 400 mm. The evaporator was formed from a cylindrical model made of copper pipe, with a length of 65 Abstract mm, inner diameter of 23 mm, and wall thickness of 1.2 mm. To prevent vapour flowing back into the liquid line, A loop heat pipe (LHP) is one of the two-phase cooling the wick extended 30 mm into the two pipes of the evapo- technologies used in passive cooling systems. The LHP is rator. In this experiment, the orientation of the HLHP was an efficient heat transfer device, but its extreme power not considered. The orientation of the system was main- density can cause dry-out at the evaporator. Many tained in the horizontal position, where the evaporator and researchers have predicted that passive devices will not condenser are at the same elevation. be able to meet future cooling challenges because of this limitation. The objective of this research is to design a modi- Result and Discussion fied LHP that overcomes the dry-out problem by adding a diaphragm pump to accelerate fluid transportation (called IExperiments were performed by varying the heat load to a hybrid loop heat pipe, HLHP). The pump installed on the evaluate the reliability and response of the HLHP under liquid line is coupled with a reservoir. The developed HLHP various working conditions. A stepwise heat load was works passively using wick capillary pressure when there applied to the evaporator (10 W, 20 W, 30 W, 50 W, 90 is no sign of dry-out. When dry-out occurs, the pump is W, 140 W, 150 W, 160 W, 170 W, 180 W, and 200 W). activated via diaphragm pumping and has a temperature Fig. 1(a) shows the heat load of 10 W applied into the controller. Thus, the working fluid is circulated by both the evaporator. After approximately 15 min, nucleate boiling capillary force and driving force of the diaphragm pump occurs, characterized by an increase in the difference in during the heat-transfer process. The operating charac- temperature between the wall and the outlet evaporator. teristics of the HLHP under a variety of heat load supply As shown in Fig. 1(b), a trend similar to that shown in Fig. and low-power start-up conditions have been investigated. 1(a) was observed. Under the 20 W heat load, the time for The experimental results indicate that the installation of a nucleate boiling was faster (approximately 12 min), and the diaphragm pump in a modified LHP system can prevent the temperature of the vapour line suddenly decreased after occurrence of dry-out in the evaporator and significantly approximately 60 min. Fig. 1(c) shows the start-up and reduce the evaporator temperature. working characteristics of the HLHP at a heat load of 30 W. The start-up characteristics for heat loads of 50 W and 90 Introduction W are shown in Fig. 1(d) and (e), respectively. These graphs show a similar trend to that in Fig. 1(c). By increasing the One method of thermal management is to use a loop heat heat load, the evaporator temperature is increased and the pipe (LHP), which is a two-phase heat transfer unit that time required for the HLHP to reach equilibrium decreases exploits the latent heat of vaporization of a working fluid. Fig. 1(f) shows the distribution of temperature in the HLHP The LHP has the ability to absorb and transfer large amounts when a heat load of 140 W was applied to the evaporator. of heat by evaporating the working fluid in the evaporator and allowing condensation in the condenser without any fluid machinery. It is known that two-phase heat transfer enables more heat to be transferred than when using single-phase sensible heating of a fluid. To operate an LHP, heat can be continuously absorbed and released over a considerable distance through two-phase isothermal transfer at the saturation temperature. According to the results of studies on thermal management, it is important to modify LHPs that are used as cooling systems in high heat flux devices. One modification, known as a hybrid loop cooling system, incorporates mechanical pumping (active) with capillary pumping (passive). 24

can work passively up to 140 W. Furthermore, the modified LHP can prevent dry-out when heat loads of 150–200 W are applied (see Fig. 3). Figure 1. Temperature distribution on the HLHP with heat load (a) 10 W; (b) 20 W; (c) 30 W; (d) 50 W; (e) 0.90 W; (f) 0.140 W Effect of the pump’s assistance Figure 2 illustrates the results of the HLHP test with a heat load of 150 W. After the heat load was applied to the evap- orator, the temperature at the evaporator wall, evaporator outlet, vapour line, and condenser inlet increased rapidly. The graph shows that nucleate boiling began in the evap- orator after less than 3 min, as indicated by the sudden decrease in the temperature difference between the evap- orator wall and evaporator outlet. With an increased power of 150 W, more vapour formed in the evaporator chamber, which can cause overheating or dry-out. Figure 3. Temperature distribution on the HLHP at 150 W, 170 W, 180 W, 200 W with pump in active and inactive condition. Figure 2. Temperature distribution on the HLHP at heat load 150 W Conclussion With pump in active and inactive condition. A diaphragm pump was installed in a modified LHP, and Figure 3 shows the temperature distribution of the HLHP an investigation into the proposed HLHP was conducted when the heat loads on the evaporator were 150 W, 170 by applying various heat loads. The results show that an W, 180 W, and 200 W under active and inactive pump LHP with pump assistance can supply a large volume of conditions (Pump ON/Pump OFF). From Fig. 3, it can be working fluid from the condenser to the evaporator. Under seen that a heat load of 150 W when the pump was acti- the application of large heat loads to the evaporator, the vated can successfully reduce the evaporator temperature HLHP developed early signs of dryout because of the to a stable state of 123 C. For heat loads of 170 W and loss of liquid in the evaporator chamber. Nevertheless, 180 W, the active pump condition succeeded in reducing when the pump was turned on, it quickly responded and the evaporator temperature to approximately 132 C and successfully prevented dry-out. In addition, an interesting 138 C, respectively. However, when a heat load of 200 W phenomenon wherein the system could properly run as a was applied, the influence of the pump’s assistance only two-phase process was also observed. However, when the reduced the evaporator temperature to approximately 157 pump was turned off, the system continued to work well. C, and the pump was apparently unable to reduce the evap- These results demonstrate that the HLHP is very promising orator temperature further. Furthermore, it can be seen and can be considered as a cooling device with a high heat that the temperature in the liquid line increased when the flux. pump was on. This indicates that the active pump allows the working fluid to circulate smoothly throughout the Acknowledgement entire loop. The authors would like to thank the Directorate of Research The pump is only activated when traditional LHP can no and Community Service (DRPM), Universitas Indonesia, for longer operate properly, i.e. the heat transfer limit has funding this research. been reached. Thus, the system works as a combination of a passive system through the capillary pump and an Reference active system using the diaphragm pump. From the results presented in this section, it appears that the traditional LHP 1. C. Park, A. Vallury, J. Perez, Advanced hybrid cooling loop technology for high performance thermal manage- ment: Defense Technical Information Center, 2006 2. N. Putra, W.N. Septiadi, H. Rahman, R. Irwansyah, Thermal performance of screen mesh wick heat pipes with nanofluids, Exp. Thermal Fluid Sci. 40 (2012) 10–17 3. N. Putra, I. Setyawan, D. Raditya, Experimental inves- tigation on contact angle of sintered copper powder wick, Appl. Mech. Mater. (2016) 575–579. 25

Segregation and Gentrification of an Informal Settlement in a City Center Ahmad Gamal Hani Mardhotillah Department of Architecture Published in: Gentrification is a form of regional development that is not International Journal of only a result of physical development. Gentrification is also Technology the process by which upper-class people invade an area SJR : 0.26 Q2 (2017) with low property values. Another indication of gentrifica- H index : 6 tion is the existence of lower-class living in the downtown IF : - area. Segregation and gentrification as forms of uneven development lead tothe differences in public facilities. The Abstract differences in public facilities in a region will create social problems and environmental problems and reduce the soci- In this research, we investigated the instance of segre- ety’s quality of life (Hardoy& Satterthwaite, 1991). gation and gentrification in Cikini, a place where formal and informal settlements coexist with walled separation. Methodology We conducted a mixedmethods research study using the following: (1) a field survey to observe the physical relation- We conducted a mixed-methods research study using the ship between the perumahan and kampung settlements; (2) following: (1) a field survey to observe the physical rela- mapping of building age and land use patterns; (3) inter- tionship between the perumahan (formal) and kampung views with key respondents, community leaders, street (informal) settlements; (2) mapping of building age and land vendors, and market vendors. We found that residential use patterns; (3) interviews with key respondents, commu- segregation in Cikini is not based on people’s racial identity, nity leaders, street vendors, and market vendors. but on their socio-economic status. The spatial separation (1) Field Observation. We conducted field surveys to of people from different socio-economic classes cannot observe, compare, and contrast the following aspects of simply be understood as inequality. It represents some formal and informal settlements in Cikini: road accessi- features of segregation, such as: (1) a fixed physical barrier bility, public facilities, housing density, and land use. We between the perumahan and kampung, despite mutual observed access to the settlement to evaluate the connec- social and economic connections between the two; and tivity between formal and informal settlements and the (2) the fact that there is no permanent residential mobility surrounding area. between the two despite the economic mobility experi- (2) Mapping. We mapped building age and land use patterns enced by people in the kampung settlement. Interestingly, to observe the relationship between the built and social we found that kampung settlement does not experience environments. We marked different buildings, their ages, gentrification while the perumahan is slowly gentrifying. and land use to evaluate the diversity of buildings and their We attribute this uniqueness of the kampung settlement to inhabitants. This was also a useful method to evaluate indi- its resilient social fabric. cations of gentrification. (3) Interviews.Interviews were conducted to identify differ- Keywords: Gentrification; Housing; Informal settlement; ences in the production processes carried out by each Kampung; Segregation food and parcel trader in Cikini. Interviews also filled data gaps that could not be obtained from the visual obser- Introduction vations and mapping, such as the role of the community and government in supporting efforts to overcome social Segregation and gentrification problems occur in every problems in formal and informal settlement communities. country in the world. Cikini, an informal settlement in In April 2018, we used open-ended interviews with three Jakarta, epitomizes the segregation and gentrification that types of respondents: residents, community leaders, and occurs in Indonesia. Cikini has two kinds of urban settle- informal merchants. The following ments: formal and informal. The difference between the two settlements creates economic and social inequality, Table 1 summarizes our interview subjects. which can be seen in the physical separation. Separation occurs because of the differences in economic growth rates which affect the income level of Cikini’s residents. As a result, the quality of public facilities and services is poor (Kato, 2012). The poor quality of public service in Cikini decreases the productivity and income of Cikini’s informal settlement residents. The disparity in income levels of the informal and the formal settlement residents creates social problems in the society. 26

Result and Discussion Table2.Characteristics of informal house in Cikini Figure 1 below shows the division of the informal and the formal settlement. It also shows the wall and the access point to enter the informal settlement. The differences in development level can be seen in the density, access, and distribution of houses in the informal and the formal settle- ments. The surrounding commercial buildings and other public facilities reflect the highlevel of development around them. Due to the high level of development, the property value around the informal settlement is also high.. Figure 1.Division of formal settlement and informal settlement Conclusion (kampung) This research finds that, in theory, Cikini’s economic growth Figure 2 shows the division of the Cikini formal settle- rate depends on its people’s skills. The difference in the level ment area. The area is divided into blocks by the roads. The of expertise between the informal settlement residents and grid-like division makes the distance taken by pedestrians the formal settlement residents generate socio-economic from their homes to the commercial area the same as the inequalities, contributing to physical boundaries between distance taken by the vehicles. In this figure, we can see the the areas. The separation of the informal and the formal street for pedestrians is emptier than the road for vehicles. settlements is a form ofsegregation. However, segrega- tion in Cikini is not based on discrimination, but on the Most of the houses in the kampung do not have a fence, difference of opportunity to access better public facili- thus increasing the interaction between neighbors. The ties and services. Although street vendors can enter the limited interior space drives people to use their exte- formal settlement area, they can only sell their products rior space, which is more comfortable due to the shade on the sidewalk. These differences in opportunity increase provided by the surrounding buildings. The informal settle- the socio-economic gap, thereby preventing the informal ment is adjacent to the formal settlement, so some houses settlement residents from living in the formal settlement face the tall wall built by formal settlement residents. The due to the high property value and price. This shows that characteristic of the informal settlement is shown in the segregation in Cikini occurs because of the differences between the economic growth rate of the informal and formal settlement of Cikini. Acknowledgement This work is supported by Hibah PITTA 2018 and funded by DRPM Universitas Indonesia. No.2365/UN2.R3.1/ HKP.05.00/2018. The authors remain responsible for the content of this paper. Reference 1. Hardoy, J.E., Satterthwaite, D., 1991. Environmental Problems of Third World Cities: A Global Issue Ignored? Public Administration and Development, Volume 11(4), pp. 341–361 2. Kato, H., 2012. Report of Preparatory Survey in Cikini. Research Institute for Humanity and Nature, Kyoto, Japan 3. Slater, T., 2017. Clarifying Neil Smith’s Rent Gap Theory of Gentrification. Tracce Urbane, Volume 1, pp. 83–101 Figure 2.Division of formal settlement and informal settlement (kampung) 27

Nanostructural Growth Investigation of ZnO Nanorods Derived from Chemical Bath Deposition for Transparent Heater Application Akhmad Herman Yuwono Lalu Suhaimi, Nofrijon Bin Imam Sofyan, Donanta Dhaneswara, Ghiska Ramahdita, Amalia Sholehah, Chairul Hudaya Department of Metallurgical and Materials Engineering Published in: dimensional nanostructures such as nanowires, nanorods, International Journal of or nanotubes have been seen as a breakthrough in the mate- Technology rials world. In this context, they can be expected to provide a much faster electron transfer via ballistic effect owing to SJR : 0.26 Q2 (2017) their pipe-like structure. Zinc oxide (ZnO) is one of inorganic H index : 6 semiconductor oxide materials which play important role in IF : - various strategic applications including sensors, optoelec- tronic and piezoelectric devices. This can be attributed to Abstract its wide band gap energy, Eg of 3.07 eV and large exciton binding energy of 60 meV at room temperature. ZnO is One dimensional zinc oxide (ZnO) nanostructures in the also well-known as one of strategic materials for piezoelec- forms of nanowire, nanorod, nanotube have been attracting tric devices due to the asymmetry in its wurtzite structure. scientific and technology interests in the last few years. In our previous works we have utilized the CBD process This current study investigated the effects of chemical bath to grow ZnOnanorods on conducting glass substrates deposition (CBD) synthesis parameters i.e. seeding solution and dedicated them for DSSC application. In the current concentration and growing time on the nanostructural char- study, we are exploring the potential of ZnOnanorods in a acteristics of ZnO nanorods and considering their potential new and important usage, i.e. transparent heater for appli- application for transparent heater. Seed solutions were cations in anti-fog, anti-icing, and de-icing functions for prepared by dissolving 1:1 equimolar zinc nitrate tetrahy- optics and optical displays. In this context, the combina- drate and hexamethylenetetraamine in water at 0°C for 1 tion of the ZnOnanorods’ high electrical conductivity and hour. Upon the synthesis, the seeding solution concentra- the optical transparency of the glass substrate on which tion was varied from 0.005, 0.025, 0.05 M. The formation of the ZnOnanorods are grown is essential. To realize this, we thin films containing ZnOnanoseeds was carried out by spin have varied the CBD synthesis parameters—seed solution coating the precursors on the conducting indium tin oxide concentration and growing time—to find the most suit- (ITO) glass substrates, followed with annealing at 200oC for able precursor composition and determine the optimum 5 minutes then further growing the ZnOnanorods at 90oC conditions for the basic nanostructural characteristics and for 3 hours. Another variation in this work was also carried optical properties for transparent heater application. out by selecting a different route upon CBD process, i.e. with a fixed 0.05 M seeding solution prepared from the Methodology same equimolar zinc nitrate tetrahydrate and hexamethy- lenetetraamine in water at 25oC for 1 hour, followed with To form the ZnOnanorods, first the ITO glass substrates the same annealing stage but continued by variation in the (2.5 cm × 2.5 cm) as the medium for nuclei and growth growing stage at 90oC for different times (3, 4 and 5 hours). of ZnOnanorods, were subjected to a cleaning procedure ZnOnanorods were characterized using x-ray diffraction, employing sequential immersions in beakers containing field emission scanning electron microscopy and ultravio- deionized water, acetone and ethanol, respectively. The let-visual spectroscopy. The results of these investigations substrates were shaken in each beaker for 8 minutes then demonstrated that with the increase in reaction time from dried in a drying oven overnight. The seed solutions with 3 to 5 hours, the band gap energy, Eg of the nanorods concentrations of 0.005, 0.025, and 0.05 M were prepared decreased from 3.63 to 3.13 eV, a consequence of the by dissolving 1:1 equimolar zinc nitrate tetrahydrate increase in their diameter and crystallite size from 325 to (Zn(NO3)2.4H2O, Merck) and hexamethylene tetraamine 583 nm and 22.68 to 34.28 nm, respectively. The desired (C6H12N4/HMTA, Merck) in water at 0°C for 1 hour. The coverage of ZnOnanorods for transparent heater appli- seed layers were formed on the surfaces of the cleaned cations was obtained with a 0.05 M seeding solution and and dried ITO substrates via the spin-coating technique, 5-hour reaction time. followed with annealing at 200oC for 5 minutes. The growth of the ZnOnanorods was subsequently completed by verti- Keywords: Chemical bath deposition; Nanorods; Reaction cally placing the ITO substrates with the seed layer in the time; Seeding concentration; Zinc oxide beaker glass containing the same solution and heating them in a muffle furnace at 90oC for 3 hours. Having completed Introduction the procedure, the samples were taken out from the beaker glass, rinsed using distilled water and dried in air at room The development of nanostructure materials has attracted temperature. In this work, we also varied the synthesis scientific and technological interests in the last few decades. route by using the same seeding solution of equimolar zinc This is due to the high demand for these materials in nitrate tetrahydrate and hexamethylenetetraamine with various strategic applications owing to their unique proper- a fixed 0.05 M but prepared at 25oC, instead of 0oC. The ties at nanometer scale which are different to those of their samples were subjected to the same annealing stage and bulk forms at the macro-and micro-scales. Therefore, one continued by variation in the growing stage at 90oC for different reaction times of 3, 4 and 5 hours. 28

Result and Discussion The morphologies of the thin films of ZnOnanorods formed with the different seeding solution concentrations are presented in Figures 1a-f. The nanorods derived from 0.005 M solution were still inhomogeneous, accompa- nied with uneven distribution in their diameters (Figures 1a and 1b). The nanorods existed as big aggregates with the average diameter of about 160 nm. Their coverage on the substrate surface was rather poor. In the solution with the 0.025 M concentration the nanorods characteristics were better, with more homogeneous and ordered structures covering almost the whole substrate surface. Figure 1.Top-view SEM images of ZnOnanorods grown via the CBD Figure 3.XRD patterns of ZnOnanorods grown by CBD process at process at 0oC with seedingsolution concentrations of: (a-b) 0.005; 25oC for: (a) 3; (b) 4; and (c) 5 hours. (c-d) 0.025; and (e-f) 0.05M. The XRD patterns of ZnOnanorods derived from the above Figure 2 contains the top-view SEM images of the resulting conditions are presented in Figure 3. By comparing them ZnOnanorods grown on ITO substrate glass with reaction with JCPDS no. 36-1451 (Wu et al., 2011), it is confirmed that time variations of 3, 4 and 5 hours, all with a seeding solu- all peaks belong to the polycrystalline pattern of hexagonal tion concentration of 0.05 M. For the 3-hour reaction time wurtziteZnO, i.e. (100), (002), (101) and (103) planes, except (Figure 2a), most of the nanorods have grown in the vertical for the small peak found at 20 of 35o in between those of direction and there is good coverage on the ITO substrate. (002) and (101), which can be referred to the ITO glass.It is In general, the nanostructural array of ZnOnanorods was interesting to note that there was a significant increase in the better than the array that resulted from the same duration (002) peak intensity when the reaction time was increased time and composition in the previous reaction at 0oC, and from 3 to 4 hours (Figures 3a and 3b), but that the inten- the average diameter of the nanorods was larger (325 vs. sity was lower at the 5-hour reaction time. The same thing 160 nm). By extending the reaction time from 3 to 5 hours, also occurred with the (101) peak. By contrast, the intensity the diameter and length of nanorods increased from 325 to of the (100) peak consistently increased with the reaction 583 nm and 0.66 to 1.98 μm, respectively. times. Such phenomena can be related to the growth nature of the ZnOwurtzite phase itself, as was demonstrated above Figure 2.Top-view SEM images of ZnOnanorods grown via the CBD via SEM analysis (Figure 2) where most of the nanorods were process at 25oC for: (a) 3; (b) 4; and (c) 5 hours. grown vertically along the c-axis. Conclusion In this study ZnOnanorods grown on glass substrates were successfully synthesized via CBD technique involving seeding and growing stages. It has been found that a seeding solution (0.05 M) prepared at 25oC can provide more homogeneous coverage of ZnOnanorods on the substrate surface with a larger average nanorod diameter, in comparison to those of with reactions at 0oC. This resulted from the ripening mech- anism in the seeding stage, which allowed the nuclei to grow more in the subsequent CBD process. Further optimization is in progress to achieve the desired combination of high optical transparency and electrical conductivity for transparent heater application. Acknowledgement This project was financially supported by the Directorate of Research and Community Services of Universitas Indonesia through the PITTA Research Grant of Universitas Indonesia, Year 2018, contract number 2370/UN2.R3.1/ HKP.05.00/2018. References 1. Chung, J., Lee, J., Lim, S., 2010. Annealing Effects of ZnONanorods on Dye-sensitized Solar Cell Efficiency. Physica B: Condensed Matter, Volume 405(11), pp. 2593–2598 2. Kadota, M., Miura, T., 2002. Shear Bulk Wave Transducer Made of (1120)-Plane Epitaxial ZnO Film on R-Sapphire. Japanese Journal of Applied Physics, Volume 41(2002), pp. 3281–3284 3. Yuwono, A.H., Sofyan, N., Kartini, I., Ferdiansyah, A., Pujianto, T.H., 2011b. Nanocrystallinity Enhancement of TiO2 Nanotubes by Post-hydrothermal Treatment. Advanced Materials Research, Volume 277, pp. 90–99 29

Developing A Conceptual Design of Transit-Oriented Development to Improve Urban Land Use Planning Mohammed Ali Berawi Bernard Elpetino Ibrahim, Gunawan, Perdana Miraj Department of Civil Engineering Published in: systems are currently being constructed. Jakarta is notorious Journal of Design and Built for its traffic problems caused by ever-increasing automo- Environment tive ownership. The paradigm of automotive use must be shifted to favor public transportation systems (Khafian, 2013; SJR : 0.18 Q2 (2017) Susantono & Berawi, 2012). With the impending availability H index : 2 of a new transit network and the need to reduce traffic, TOD IF : - should be proposed as part of the transit network. Abstract Currently, light rail transit (LRT) is being implemented as one of the transit systems in Jakarta as phase 1 of the construction Transit-oriented development (TOD) is an urban develop- of the transit network. This phase includes an LRT network ment approach that integrates transit stations to establish connecting East Jakarta and Bekasi. Several TOD plans have transit-oriented behavior. It is a systematic approach to been disclosed for select transit stations. This research uses reduce automotive dependency by facilitating increased four transit stations—East Jakarta 1, East Jakarta 2, Bekasi 1 accessibility to diverse destinations within walking distance. and Bekasi 2—as a case study to evaluate the potential for Indonesia has recently adopted this development approach. TOD. The results can be used as a benchmark for imple- This paper is intended to provide academic insight into the menting similar TOD in domestic and foreign projects. current Indonesian implementation of TOD. A comparative model is created based on benchmark studies and research Result and Discussion on current TOD principles and theories. Based on a compar- ative analysis between the model and current developments, A benchmark model to compare to the current Indonesian Indonesian TOD can benefit from further development area TOD is synthesized from properties of Union Square, Namba and arrangement adjustment to conform to TOD design plan- Parks and D-Cube City. The benchmark model is determined ning principles. using the mean values of building coverage ratio (BCR) and floor aspect ratio (FAR), as well as the proportion of floor Keywords: Conceptual design, land use, TOD, urban areas used for amenities. The BCR is the ratio of the building development area divided by the land size area. The building area is the floor space of a building when looking down from above Introduction (aerial view). BCR should not to be confused with FAR, which measures the total floor space in a building. BCR value can be Transit-oriented development (TOD) has attracted the obtained using the formula BCR (%) = (building area) / (site interest of city planners and researchers in recent years (Papa area) × 100 (Sekai Property, 2016). Common amenities found & Bertolini, 2015). TOD is a form of development intended to in the benchmark TODs are residential, office, commercial/ functionally integrate transit and surrounding developments retail and hotels. The benchmark model has a BCR value of (Knowles, 2012). TOD is often perceived as an effective 92% and a FAR value of 7.29. means to combat the problems caused by automotive use. Transportation has historically influenced urban development As of now, TOD developments in Indonesia have yet to indi- patterns (Ratner & Goetz, 2013). The increasing ownership of cate density measurements, reflected by a BCR below 50%. private vehicles has encouraged urban sprawl and congestion Meanwhile, the benchmark TODs show a BCR of at least in cities worldwide (Knowles, 2012; Negara, 2015). With the 80% (Namba Parks). The FARs of the Indonesian TODs are emphasis on transit, TOD is often implemented to reduce the lower than 5. TODs in Indonesia are typically developed use of non-renewable vehicles. and sold only as apartment building complexes. Most floor areas are used for residential purposes. In addition to a lack TOD has been successful in urban development in the US of diversity, the current development also shows a lack of (Ratner & Goetz, 2013). Historically, American cities have destinations. Such development only address the inhabi- grown as a result of increased automotive use. However, tants’ need for housing. Moreover, without the workplace there has been a shift in the development approach that and commercial areas within the transit network, people favors walkable and sustainable development. Yet, TOD would require another form of transportation to reach is not a particularly new phenomenon. For example, work locations and other daily activities. This will poten- there was a close correlation between transit and prop- tially discourage the use of transit and instead promote erty development in Europe even before the popularity of the use of private vehicles. With a relatively low BCR, the private vehicle ownership (Knowles, 2012). Currently, TOD apartment complex development is also planned in a sparse is being implemented in the urban development of many block plan with gaps between towers, although in some cities (Knowles, 2012; Kwon, 2015; Cervero & Murakami, projects the towers are connected by the retail podium, 2009). a disjoint among building blocks commonly found weaved together by roads designed for cars. This may discourage Recently, Indonesia’s capital city of Jakarta has undergone pedestrians from walking around the site. significant infrastructure development, and new transit Based on the above observations, it is concluded that the TODs in Indonesia have failed to fulfill the density and diver- sity requirements. The space within buildings designed 30

to accommodate cars, to navigate the site or for outdoor the lack of coherent transit-to-development integration. parking. It is counterintuitive to the common goal of TOD of Moreover, the sparse layout and road construction within discouraging automotive use within TODs. Although most the development area prioritizes vehicular access rather TODs in Indonesia are developed within a 200-meter radius than pedestrian walkways, hinting that planning is still around a transit station, the actual distance pedestrians must favouring a vehicle-centric design. traverse to navigate the sites is still debatable. Station and TOD’s property development are not integrated and should Based on the previously described TOD benefits, TOD as a be appropriately designed to accommodate the quality of new development approach in Indonesia promises advan- people movement. tages over conventional approaches to development. Therefore, policymakers should assess the potential of Successful TOD projects often feature dense development TOD implementation in Indonesia and become proactively reflected by high BCR and FAR values. Density enables involved in policymaking for better national development flexibility in accommodating diverse amenities on relatively growth. Furthermore, future research should develop limited urban land plots. Well-designed dense develop- improved conceptual plans that integrate transport service, ments benefit inhabitants by keeping everything within public facilities and commercialization to further improve walking distance. The benchmark comparison with other the benefits of TOD implementation in Indonesia. TOD projects revealed a BCR value of 92% and a FAR value of 7.29. Applying this pattern to the current Indonesian Conclusion TOD plans will significantly increase the floor areas. This improvement may benefit investors by allowing more prop- Based on a benchmark comparison, Indonesian TOD plans erties to be developed and sold in the future. have yet to conform with TOD principles, as indicated by relatively low BCR and FAR values. By studying the With the increased floor areas, Indonesian TODs should implementation of TOD principals in successful projects, include more amenities. In the benchmark model, residen- a benchmark model was generated to allow comparative tial space in the TOD must occupy less than 50%. With analysis between the benchmark design and current devel- the increase of available floor area due to BCR and FAR opments. The study revealed the lack of area evident in adjustments, floor area use in Indonesian TODs can be designs with low BCR and FAR values. By adjusting these used to accommodate amenities such as those included in values, more useful space would become available to the benchmark model. The floor use in each TOD project include more developments to result in a design that better should be adjusted to be similar to the floor use in the conforms to TOD principles. BCR values can be increased benchmark model. Due to the physical characteristics of up to 90% from 20% using the current plan, and the FAR each project site, there are slight variations. Residential amount can be increased from 2.35 to 7.24. Furthermore, towers in project 1 in East Jakarta now only take up 46%, the benchmark model has incorporated comprehen- down from the previous 90%. It is now closer to the bench- sive designs found in other successful projects. The plan mark model’s 50% residential floor area use, allowing for the includes various amenities in a compact arrangement that rest of the space to accommodate offices, more commercial ensures accessibility and walkability. Based on these find- areas and hotels. Similarly, after increasing the floor area ings, current TODs can benefit from the addition of facilities by adjusting the BCR and FAR, the floor area proportions other than apartments while maintaining compactness and of the Indonesian TOD projects better reflect that in the accessibility. benchmark model. Acknowledgement A commercial area as a transition between the transit station and the rest of the development keeps the TOD This research was supported by grants from Universitas areas accessible. TOD project can construct those ameni- Indonesia and the Ministry of Research and Higher ties into integrated development area. By utilizing a Education, the Republic of Indonesia. comprehensive density and diversity design, a pedestri- an-friendly and convenient TOD can be achieved. Learning References from benchmark TODs, commercial areas can function as a convenient way of integrating the rest of the devel- 1. Chung, J., Lee, J., Lim, S., 2010. Annealing Effects of opment. The commercial area can be integrated with the ZnONanorods on Berawi, M. A., Miraj, P., Berawi, A. transit station, while towers can be situated above or phys- R. B., Silvia, & Darmawan, F. (2016). Towards self-suf- ically connected in other arrangements. This way, the ficient demand in 2030: Analysis of life-cycle cost for commercial area can also function as comfortable circula- Indonesian energy infrastructure. International Journal tion space between the transit station and the rest of the of Technology, 7(8), 1444-1453. development. 2. Calthorpe, P. (1993). The next American metropolis: Benchmark projects show how density is an indicator Ecology, community, and the American dream. New of conventional TOD design reflected by efficient BCR York: Princeton architectural press.. and FAR. BCR and FAR allows more efficient land use and the possibility of developing a multi-use project. 3. Cervero, R., & Kockelman, K. (1997). Travel demand With an innovative design, density can also contribute to and the 3 Ds: Density, diversity, and design. pedestrian accessibility by keeping the amenities within Transportation Research Part D: Transport and walking distance, thus reducing automotive depen- Environment, 2(3), 199-219. dency. Indonesian TODs can start improving project plans by adopting a more efficient BCR and FAR. Currently, 4. Kwon, Y. (2015). Sejong Si (City): are TOD and TND Indonesian TODs show little progress in terms of density, models effective in planning Korea’s new capital? diversity, design, destination accessibility and distance to Cities, 42, 242-257. transit. Physical developments have not reflected a dense, diverse or pedestrian-oriented design. This is evident by 31

Antiviral Activity of Acanthaster planci Phospholipase A2 Against Auman Immunodeficiency Virus Anondho Wijanarko Kenny Lischer, Heri Hermansyah, Diah Kartika Pratami, Muhamad Sahlan Department of Chemical Engineering Published in: cell histamine-releasing, phospholipase A2 (PLA2), anticoag- Veterinary World ulant, and cardiovascular activity, as well as mouse lethality [1]. AP-PLA2 exhibits some of the same characteristics as SJR : 0.39 Q2 (2017) PLA2 from snake and bee venom, suggesting that AP-PLA2 H index : 17 could potentially have anti- viral activity against HIV. IF : - Methodology Abstract AP-PLA2 was isolated using the extraction method Aim: Investigation of antiviral activity of Acanthaster planci described by Savitri et al. [2]. Briefly, 50 g of venomous A. phospholipase A2 (AP-PLA2) from moluccas to human planci spines was sonicated in 100 ml 0.01 M phosphate immunodeficiency virus (HIV). buffer (pH 7.0) and 0.001 M CaCl2, and the extract was centrifuged at 15,000 rpm at 4°C for 30 min. The super- Materials and Methods: Crude venom (CV) and F20 (PLA2 natant (CV) was obtained. The A. planci CV was heated at with 20% fractioned by ammonium sulfate) as a sample of 60°C for 30 min and centrifuged at 15,000 rpm at 4°C for PLA 2 obtained from A. planci’s extract were used. Enzymatic 30 min. The supernatant (heated venom) was thus obtained. activity of PLA2 was determined using the degradation of Isolate of AP-PLA2 was obtained from the heated venom phosphatidylcholine (PC). Activity test was performed using by precipitation with 20% saturated ammonium sulfate and in vitro method using coculture of phytohemagglutininstim- centrifugation at 30,000 rpm at 4°C. ulated peripheral blood mononuclear cell (PBMC) from a blood donor and PBMC from HIV patient. Toxicity test of Subsequently, precipitated AP-PLA2 was dissolved in 0.01 M AP-PLA2 was done using lethal concentration required to pH 7.0 phosphate buffer (K2HPO4 and KH2PO4) and 0.001 kill 50% of the population (LC50). M CaCl2 for storage at 4°C until use. Throughout the afore- mentioned purification pro¬cedure, the activity of AP-PLA2 Results: AP-PLA2 F20 had activity and purity by 15.66 times was assessed using a method described by Marinetti based bigger than CV. The test showed that the LC50 of AP-PLA2 on its enzymatic activity on egg yolk [3]. is 1.638 mg/ml. Antiviral analysis of AP-PLA2 in vitro showed the inhibition of HIV infection to PBMC. HIV culture Result and Discussion with AP-PLA2 and without AP-PLA2 has shown the number of infected PBMC (0.299±0.212% and 9.718±0.802%). AP-PLA2 is an enzyme in the phospholipase group. Its Subsequently, RNA amplification of HIV using reverse tran- activity can be measured using egg yolk because of its ability scriptase-polymerase chain reaction resulted in the decrease to degrade PC: The purer the yolk, the higher the AP-PLA2 of band intensity in gag gene of HIV. activity. CV exhibited less specific activity compared with others. Meanwhile, F20 exhibited greater specific activity Conclusion: This research suggests that AP-PLA2 has the and made the egg yolk 15.7 times more pure than CV did. potential to develop as an antiviral agent because in vitro experiment showed its ability to decrease HIV infection in Gel electrophoresis results are shown in Figure-1. These PBMC and the number of HIV ribonucleic acid in culture. results, taken together with the results of the immuno- fluorescence assay, indicate that HIV was present in the Keywords: Acanthaster planci, antiviral activity, human range of 105 bp in the control HIV culture as well as in the immunodeficiency virus, Indonesia, phospholipase. AP-PLA2+HIV culture. Introduction Figure 1. Gel electrophoresis data after reverse transcriptase- polymerase chain reaction human immunodeficiency virus (HIV) The crown-of-thorns starfish Acanthaster planci is one of ribonucleic acid (RNA) fluorescence. Lane 1: HIV culture was added to the most dangerous coral predators currently contributing to PLA2 (PLA2+HIV). Lane 2: HIV culture without treatment (HIV). Lane the degradation and loss of Indonesia’s highly diverse reefs, 3: Cultured line control of a positive HIV RNA (K+). Lane 4: The culture which is a major problem for coral management programs of peripheral blood mononuclear cell. Lane 5: Cultured line control of in the Pacific Ocean. Outbreaks of A. planci have occurred a negative HIV RNA (K-). Lane 6: Standard protein. at many locations throughout the Indo-Pacific region as a result of anthropogenically elevated nutrient levels and overfishing. The glandular tissue around the venomous spines on the body surface of A. planci produces toxins. Crude venom (CV) extracted from A. planci has a range of biological activities including hemo¬lytic, myonecrotic, capillary permeability-in-creasing, hemorrhagic, edema-forming, mast 32

An immunofluorescence assay incorporating FITC cytom- phospholipid bilayer envelope, causing the virus to become etry followed by flow cytometry was used to assess the inactive. The findings of this study sup¬port the hypoth- number of HIV-infected cells in the PBMC culture: The esis that AP-PLA2 exhibits antiviral activity that may inhibit greater the fluorescence, the higher the infection rate HIV replication. Our results are similar to those reported by (Figure-2). previous researchers, who concluded that a human-specific secretory PLA2 (sPLA2-X) could neutralize HIV-1 through Figure 2. Cytometry of immunofluorescence assay using fluorescence degrada¬tion of the HIV membrane. isothiocyanate in (a) peripheral blood mononuclear cell culture as control negative, (b) no treatment human immunodeficiency Conclusion virus (HIV) culture as a positive control, (c) HIV culture treat by the addition of PLA2 (PLA2+HIV). The peak by green color on the right AP-PLA2 has been shown to decrease the HIV infection side of a threshold shows among of expression of HIV protein. The rate and the HIV-specific RNA concentration in in vitro graph indicates that amount of expressed HIV protein in PLA2+HIV PBMC culture. To conclude, the A. planci crown based on culture is less than no treatment HIV culture. HIV infection in PBMC was signifi¬cantly around 98%. In The untreated HIV culture produced five green peaks, while the present study, AP-PLA2 was produced from CV by a the AP-PLA2+HIV culture produced only two green peaks. simple extraction process. Because CV is a waste material The cell fluorescence in the PBMC, HIV, and AP-PLA2+HIV and the extraction pro¬cess is simple, AP-PLA2 is envi- cultures was approximately 2.16%, 9.72%, and 0.29%, ronmentally friendly and cheap. Although further study is respectively (Figure-3). required to deter¬mine the safety and efficacy of AP-PLA2 The antiviral activity of CV is low because it is impure, in vivo throughout the entire human body, this waste unlike F20, which has higher AP-PLA2 con¬tent and there- product is a promising source of a potential anti-HIV agent fore exhibits more significant antiviral activity. that could potentially provide an effective solution not only to the challenges facing coral reef conservation. programs Figure 3. Percentage of human immunodeficiency virus (HIV) but also in treating one of the most danger¬ous diseases infection in peripheral blood mononuclear cell (PBMC) culture line. affecting humanity today. After addition of PLA2, proportion of HIV infection was decreased significantly from HIV infection without treatment (HIV) about Acknowledgement 9.718±0.802% (n=4) to HIV infection with treatment (PLA2+HIV) 0.299±0.212% (n=4). Meanwhile, control was about 2.15±0.802% This study fully supported by the United States Agency (n=4). for International Development (USAID) through the Qualitative analysis by immunofluorescence cytom- Sustainable Higher Education Research Alliance (SHERA) etry indicated that AP-PLA2 could decrease the amount Program for Universitas Indonesia’s Scientific Modeling, of HIV protein that was expressed in PBMCs. AP-PLA2 Application, Research and Training for City-centered reacts with phospholipids breaking them down into fatty Innovation and Technology (SMART CITY) Project, Grant acids and phosphoglycerides; in this way, it lyses the HIV #AID- 497-A-1600004, Sub Grant #IIE-00000078-UI-1 (No.0139/UN2.R3.SC /HKP.05.01/2018). Special thanks to our colleague, Dr. R. Fera Ibrahim and Aroem Naroeni for their kindly assistance for HIV anti-viral drugs test using A. planci PLA2 at Institute of Human Virology and Cancer Biology, Universitas Indonesia. References 1. Ota, E., Nagai, H., Nagashima, Y. and Shiomi, K. (2006) Molecular cloning of two toxic phospholipases A2from the crown-of-thorns starfish Acanthaster planci venom. Comp. Biochem. Physiol. B Biochem. Mol. Biol., 143(1): 54-60. 2. Savitri, I.K.E., Ibrahim, F., Sahlan, M., and Wijanarko, A. (2011) Rapid and Efficient Purification Method of Phospholipase A2 from Acanthaster planci. Int. J. Pharma. Bio. Sci., 2(2): 401-406. 3. Marinetti, G.V. (1965) The action of phospholipase A on lipoproteins. Biochim. Biophys. Acta Lipids Lipid Metab., 98(3): 554-565. 33

Nanostructure Properties and Dye-Sensitized-Solar-Cell Open Circuit Voltage of A TiO2 Aerogel and Pre-Hydrothermally Treated Xerogel Bambang Priyono Akhmad Herman Yuwono, Badrul Munir, Muhammad Hasan Mustofa, Faizah Department of Metallurgical and Materials Engineering Published in: semiconductor layers in DSSCs is TiO2 (Sofyan et al., 2017). International Journal of TiO2 nanoparticles have gained importance for the fabri- Technology cation of photoanodes, which comprise a monolayer of highly porous material (Sugathan et al., 2015). The photo- SJR : 0.26 Q2 (2017) electrode in a DSSC is sometimes also referred to as the H index : 6 working electrode, and under commercial development, IF : - it generally includes titania nanoparticles. The crystal phase of the TiO2 particles used in DSSCs is generally the Abstract anatase phase because of its high dye-absorbance proper- ties (Nursama & Muliani, 2012). The correlation between Dye-sensitized solar cells (DSSCs) are third-generation TiO2 nanostructure properties such as crystallite size, photovoltaic devices, which are considered to be a very surface area, and band-gap energy and the performance of promising renewable-energy source that offers an alterna- the material as a semiconductor for better and more effi- tive to fossil fuels due to their low cost, ease of production, cient DSSCs was investigated. and eco-friendliness. One of the most important compo- nents in DSSCs is the TiO2 layer, which serves as an Methodology active inorganic semiconductor oxide for photoelectron activity. Herein, TiO2 nanoparticles were synthesized via First, a TiO2 sol was prepared by hydrolysis of titanium a sol-gel process using titanium tetra-n-butoxide, ethanol, tetra-n-butoxide (Kanto Chemical, Japan) by dropwise hydrochloric acid, and deionized water at molar ratios of addition of a mixture of hydrochloric acid and water in an 0.4:0.83:1:1.39 upon sol preparation, followed by hydro- ethanol solution under vigorous stirring to obtain a trans- thermal processes at three different temperatures (i.e., parent sol solution. The molar ratio of titanium tetra-n 100°C, 120°C, and 150°C); ambient drying; and multi-step butoxide, ethanol, hydrochloric acid, and deionized water calcination. For comparison, TiO2 aerogel nanoparticles was 0.4:0.83:1:1.39. The mixture was stirred for three hours were also prepared via supercritical extraction followed to stabilize the solution and then sealed in a container for by multi-step calcination. The samples were analyzed by 1–2 days at room temperature. The gels were processed X-ray diffraction, Brunauer–Emmett–Teller surface-area in two different ways: In the first route, they were treated measurements, UV–Vis spectroscopy in the diffusere- hydrothermally in a Teflon-lined stainless-steel auto- flectance-) mode, and scanning electron microscopy. The clave (Parr-Moline, Illinois USA) equipped with a specially results showed that the prehydrothermally treated samples modified sample holder, sealed, and placed in an oven at exhibited band-gap energies of 3.34, 3.29, and 3.32 eV different temperatures of 100°C, 120°C, and 150°C for after treatment at 100°C, 120°C, 150°C, respectively, 14 hours. Then, they were dried at 70°C for 24 hours in whereas the aerogel sample had a band-gap energy of 3.33 a drying oven and subjected to a three-stage (multi-step) eV. Open-circuit-voltage measurements revealed that the calcination process at 150°C, 300°C, and 420°C for one DSSCs fabricated by pre-hydrothermal treatment at 120°C hour each in a tube furnace to improve the crystallinity. generated a higher voltage (320 mV) than aerogel cells (21 mV). The samples treated by the pre-hydrothermal and SCE processes were characterized by X-ray diffraction (XRD, Keywords: Aerogel; Multi-step calcination; Open circuit Bruker AXS θ−2θ) to identify the TiO2 anatase phase and voltage; Pre-hydrothermal treatment; Supercritical determine the crystallite size through Scherrer’s equation. extraction For phase-identification purposes, an XRD-pattern analysis was performed using the X’Pert High Score Plus software Introduction based on the JCPDS 211272 reference numbers. Brunauer– Emmet–Teller (BET) (Quantachrome NOVA 1200e) tests The use of renewable energy is a key way to overcome the were performed to determine the surface area; UV– world’s energy crisis. Dye-sensitized solar cells (DSSCs) are Vis diffuse-reflectance spectroscopy (DRS, Shimadzu one of the most attractive solar-energy harvesting methods UV-2401PC) measurements were performed to deter- due to their low cost, high photon conversion efficiency, mine the band-gap energy, which was calculated through and good stability (O’Regan & Grätzel, 1991). Many efforts the Kubelka–Munk function using a Tauc equation anal- have been made to improve the performance of DSSCs ysis; and scanning electron microscopy (SEM) images were (Khan et al., 2017) with an important approach being the taken to determine the morphology of the TiO2 structures. optimization of the photoanode. In this case, the perfor- The performance of DSSCs assembled from nanoparticles mance improvement relates to the base material, which is resulting from both methods was tested by measuring the influenced by the structure of the oxide layer having a high open circuit voltage (Voc) under the light beam of an over- surface area to absorb sensitizing dyes and maximize the head projector. performance as required. One of the most commonly used 34

Result and Discussion Our results suggest that pre-hydrothermal treatment can make stiff Ti–OH networks become more flexible, leading to The XRD patterns of hydrothermal samples obtained at the formation of Ti–O–Ti arrangements after completion of 100, 120, and 150˚C are shown in Figure 1, whereas the the hydrolysis process. These Ti–O–Ti structures improve the pattern of an aerogel sample is presented in Figure 2 crystallinity of TiO2 and lead to a better performance of the material. The presence of a stiff Ti–OH network in the aerogel Figure 1. XRD patterns of calcined hydrothermal samples obtained affects the crystallinity of the material and hinders the forma- at: (A) 100°C; (B) 120°C; and (C) 150°C tion of Ti–O–Ti arrangements. Thus, Ti– O–Ti networks are better distributed in hydrothermally treated samples than Figure 2 XRD patterns of: (D) an as-dried aerogel; and (E) a calcined in the aerogel. The highest Voc value was observed for the aerogel pre-hydrothermally treated sample obtained at 120°C, which As shown in Figure 3, the broadening of the peaks in the indicates that the optimum conditions were achieved at this XRD pattern was analyzed to estimate the crystallite size. temperature. This was done by determining the widening at half the inten- sity of the diffraction peak (or full width at half maximum, Conclusion FWHM) using the Scherrer equation, as summarized in the comparison diagram. Well-defined peaks indicate the All the samples resulting from this research had a nanocrys- formation of the anatase phase by multi-step calcination at talline structure and were successfully assembled into DSSCs temperatures of 150°C, 300°C, and 420°C. FWHM in each to study their ability to convert light into electrical energy, as pre-hydrothermal and aerogel samples processed using shown by their Voc values. The properties of the TiO2 aerogel SCE process to estimate the average size of crystallite size reported herein exceeded those of materials presented diameter after calcination, whether the TiO2 anatase of in previous research, exhibiting a larger surface area and this works still has the nano-size crystallite achieving a high enough crystallinity. Furthermore, compared to samples submitted to pre-hydrothermal treatment, the Figure 2 XRD patterns of: (D) an as-dried aerogel; and (E) a calcined aerogel had the highest surface area (110.31 m2/g) and a crys- aerogel tallite size of 8.07 nm. Regarding the crystallite size, the largest structures were obtained by pre-hydrothermal treatment at 150o0C (9.73 nm), with a surface area of 82.17 m2/g. The size of the samples treated at 120oC was 7.79 nm (surface area: 85.43 m2/g) and that of the materials treated at 100oC was 7.45 nm (in this case the surface area was only 71.31 m2/g). Pre-hydrothermal treatment was performed to suppress the fast development of stiff Ti–OH structures, which lead to largely amorphous particles. This treatment transforms the Ti–OH network into a flexible Ti–O–Ti arrangement. Subsequent multi-step calcination enhances the crystallinity of the resulting TiO2 particles further, thus confirming the findings of previous researchers. Voc measurements revealed that DSSCs fabricated using the aerogel provided 21 mV. The best results were obtained for the pre-hydrothermally treated sample prepared at 120oC (320 mV), followed by the samples treated at 150o and 100oC, respectively. Acknowledgement The authors would like to acknowledge financial support from the Directorate of Research and Community Services - Universitas Indonesia (DRPM-UI) through Hibah Riset Madya Universitas Indonesia under contract no. DRPM/ RII/175/RM-UI/2013 References 1. Brodsky, C.J., Ko, E.I., 1994. Effect of Drying Temperature on the Physical Properties of Titania Aerogels. Journal of Materials Chemistry, Volume 4(4), pp. 651–652 2. Dai, S., Wu, Y., Sakai, T., Du, Z., Sakai H., Abe, M., 2010. Preparation of Highly Crystalline TiO2 Nanostructures by Acid-assisted Hydrothermal Treatment of Hexagonal-structured Nanocrystalline Titania/ Cetyltrimethyammonium Bromide Nanoskeleton. Nanoscale Research Letters, Volume 5(11), pp. 1829–1835 3. Ge, L., Xu, M., Fang, H., Sun, M., 2006. Preparation of TiO2 Thin Films from Autoclaved Sol Containing Needle-like Anatase Crystals. Applied Surface Science, Vol 253(2), pp. 720–725 35

High-Performance Radiation Design of a Planar Bow-Tie Antenna Combined with a Dielectric Lens and Cascaded Matching Layers at Terahertz Frequencies Catur Apriono Arie Pangesti Aji, Teguh Wahyudi, Fitri Yuli Zulkifli, Eko Tjipto Rahardjo Department of Electrical Engineering Published in: with the legacy data modulation technique. Therefore, a International Journal of THz wave carrier frequency is necessary to increase band- Technology width and fulfil requirements (Song & Nagatsuma, 2011). SJR : 0.26 Q2 (2017) Methodology H index : 6 IF : - Planar bow-Antenna Figure 1 illustrates a schematic of the bow-tie antenna. It Abstract consists of two identical triangles separated by a specific gap distance. A discrete port with a 50 Ω input impedance is The demand for high-speed data transmission has increased used as the feeding method, set in the gap. High-resistivity significantly in the last decades. Terahertz (THz) frequen- silicon with a relative dielectric constant (������������) set to 11.9 cies, which lie between 100 GHz to 10 THz, have been was chosen due to its low refractive index dispersion and considered to be the solution to the demand. However, the low absorption, which are suitable for electromagnetic low gain and low efficiency of a THz antenna remain issues wave radiations (Ronne et al., 1997). that hinder reasonable performance for various applica- Table 1 shows the optimum parameters after characteri- tions. This paper proposes the design of a high-gain and zation for a resonant frequency of 1 THz. Therefore, the high-efficiency planar bow-tie antenna for applications substrate dimension and thickness values are considered in using THz frequencies. A planar bow-tie on a high-re- order to deal with the substrate wave. sistivity silicon substrate is considered in order to obtain broadband characteristics. To increase gain and efficiency, Figure 1. Schematic of the bow-tie antenna design on a high a dielectric silicon lens and a matching layer based on the resistivity silicon substrate quarter-wavelength are applied in the design. From simu- Table 1. Antenna and substrate parameters lations using Computer Simulation Technology (CST) Microwave Studio, gain and radiation efficiency up to 32.69 Silicon Dielectric Lens dB and 90.4% are obtained, respectively. This proposed Figure 2 illustrates a dielectric lens designed on top of the design has shown high radiation performance suitable for substrate. To form a hemisphere shape, the lens radius (R) is high-speed transmission systems. set to 3000 µm, or half the dimension of the Si substrate (s). The center point of the lens is at the top of the substrate, Keywords: Bow-tie; High resistivity silicon lens; matching or at the point of substrate thickness (h). The lens dielectric layer; Terahertz. constant is determined to be same as the substrate dielec- tric constant to avoid a mismatched condition between the Introduction two. The terahertz (THz) wave radiation region, located between the microwave and the infrared regions, is the transition region between the electronic and photonic domains (Akyildiz et al., 2014). The THz wave is not applied as widely as the electronic and photonic domains, although there is potential for this frequency band. The availability of reasonable performance equipment, especially for THz wave sources and detectors, is one of the main issues of THz wave system development. As femtosecond lasers and photoconductive antennas have been available since the 1980s to produce THz waves (Mourou et al., 1981), some areas have begun to utilize these waves, such as medical science, pharmacology, and security (Siegel, 2002). This region has also been considered to fulfil the demand for high-speed wireless data transmission and various commu- nication applications (Hirata et al., 2012). High-speed data transmission demand has increased significantly in the last decades. Some modifications have been made to improve data capacity by applying advanced modulation schemes and signal processing. In the future, a new spectral resource is needed to increase data speed. The large bandwidth of THz waves can be utilized to obtain higher data rates, even 36

Figure 2. Schematic of a dielectric lens structure Figure 5. Radiation efficiency versus substrate thickness Result and Discussion Table 3 is a summary of the gain and efficiency from the theoretical and simulation results. We compare the simu- Return loss (S11) parameter lation results in the optimum conditions, which is the trade-off between gain and efficiency, as shown in Figure Figure 3 shows the S11 simulation results of the bow-tie 6. Table 3 shows that the simulation results are comparable antenna combined with a silicon dielectric lens. The reso- and consistent with the theoretical ones. The discrepancies nant frequency of 1 THz remains at around -20 dB, while are due to the dipole theoretical approximation rather than the bandwidth determined at the threshold of -10 dB is the bow-tie antenna. 368.76 GHz. surface vector. The return loss at 1 THz is around -20 dB. Figure 3. S11 Parameter simulations of the bow-tie antenna Figure 6. Simulation results of radiation efficiency and gain on the combined with dielectric lens cascaded matching layer Radiation Pattern Figure 4 shows the radiation pattern simulation results Table 3. Theoretical and simulation result comparison of gain and of the bow-tie antenna combined with a dielectric lens at radiation efficiency 1 THz for a plane of (a) ϕ = 0° (E-plane) and (b) ϕ = 90° (H-plane). The highest realized gain is 10.18 dB, obtained Conclusion from the main lobe magnitude of Figure 6a. The radiation and total efficiency are -1.592 dB (69.3%) and -1.63 dB A bow-tie planar antenna on a high-resistivity silicon (68.7%), respectively. substrate combined with a capacitive bar provided wide- band bandwidth of around 368 GHz. The antenna combined Figure 4. Radiation patterns of the bow-tie antenna for: (a) ϕ = 0°; with optimum substrate thickness and a hemispherical and (b) ϕ = 90° silicon lens provides gain and beam width of 31.31 dB and Radiation Efficiency 3.1o, respectively. The matching layer technique of the Figure 5 shows the radiation efficiency for different quarter-wavelength and the five cascaded matching layers substrate thicknesses; a maximum efficiency of 71.8% is has radiation efficiency and gain of 90.4% and 32.69 dB, obtained at the substrate thickness of 900 µm, but effi- respectively. The proposed design can be considered to ciency starts to drop from a thickness of 1000 µm and provide a high radiation performance antenna for various beyond. From the results, we can conclude that substrate THz applications. thickness has a slight effect on the antenna’s efficiency. This condition comes from the radiation wavefront conforming Acknowledgement with the lens surface, where the optimum thickness to pass through the interface is around 900 µm. This work was supported by PITTA 2017 Grant, contract number: 754/UN2.R3.1/HKP.05.00/2017, year 2017, Universitas Indonesia. References 1. Hirata, A., Kosugi, T., Takahashi, H., Takeuchi, J., Togo, H., Yaita, M., Kukutsu, N., Aihara, K., Murata, K., Sato, Y., Nagatsuma, T., Kado, Y., 2012. 120-GHz-band Wireless Link Technologies for Outdoor 10-Gbit/s Data Transmission. IEEE Transactions on Microwave Theory Techniques. Volume 60(3), pp. 881–895 2. Mourou, G., Stancampiano, C.V., Antonetti, A., Orszag, A., 1981. Picosecond Microwave Pulses Generated with a Subpicosecond Laser-driven Semiconductor Switch. Applied Physics Letters, Volume 39, p. 295 3. Siegel, P.H., 2002. Terahertz Technology. IEEE Transactions on Microwave Theory Technology. Volume 50(3), pp. 910–928 4. Song, H-J., Nagatsuma, T., 2011. Present and Future of Terahertz 37 Communications. IEEE Transaction on Terahertz Science and Technology. Volume 1(1), pp. 256–263

Living Material as a Building Façade: The Effect of Moss Growth toward Mechanical Performance on Pre- vegetated Concrete Dalhar Susanto Intan Chairunnisa Department of Architecture Published in: or artificial growing mediums, which most of these systems International Journal of need for more complex façade design (Rakhshandehroo et Technology al., 2015). Other plants grow on the surfaces of building façades as hybrid materials of living things and an object SJR : 0.26 Q2 (2017) called living material. A plant which does not require special H index : 6 care is moss. Moss can grow on wood panels without any IF : - light, water, or specific care. Abstract Methodology The increasing construction of tall buildings in Indonesia Three bryophite mosses chosen in this research were has led to the reduction of green areas and the increase Bryum apiculatum, Barbula indica, and Hyophila invo- use of building materials such as concrete panels. This luta, which are commonly found growing on the surface research sees the potential of building façades created of wet cementitious material (Putrika, 2015) (Figure 1). by using concrete panels as media for growing plants to These mosses were planted by transplanting them onto replace those green areas that have decreased. The plants the surface of concrete as a growing media. The surface that are used in this research are selected based on the of the concrete panels were conditioned before planting to climatic conditions of tropical countries in Indonesia. The support the moss growth. The next step was to gather moss plants that are chosen are fast growing, require less main- and prepare the moss culture media for growing. Things tenance, and are considered to be suitable for cementitious to take into consideration before transplanting mosses materials. A previous study has found that bryophyte moss were sunlight, a pH value between 5–5.5, 60% moisture, meets those criteria. This research compares the perfor- and daily watering. The moss was mixed with yogurt and mance of pre-vegetated and non-pre-vegetated concrete water, blending it into a slurry consistency and painting it panels by investigating compressive strength through labo- on the concrete surfaces (Udawatha et al., 2018) as shown ratory experiments. Three mixes of concrete, three moss in Figure 1. species, and three concrete surfaces were examined with 9 panels, 27 cube samples, and 9 cube controls. The study Figure 1. Process to the plant the moss contributes to a growing body of research on the sustain- ability of building façades in which further investigation is Concrete is created by mixing cement, aggregate, water, needed. and a low concentration of additional mixtures. The stirring process can be carried out on-site, or prefabricated mate- Keywords: Living material; Precast concrete panel; rial can be acquired in the form of blocks or other shapes Pre-vegetated concrete panel (Berge, 2009). The mixtures of concrete in this study were chosen based on their potential as a growing media Introduction for moss. The mixtures were divided into three types: a mixture of Portland Cement concrete and two other Building development has been increasing to fulfill human mixtures of green concrete, which is more environmentally needs and activities. A broad range of housing, apartment, friendly. This research will focus on the K-175 standard as retail, and skyscraper developments in the world are mostly a non-structural construction of walls on the skin of build- constructed with concrete. Large-scale urban develop- ings. K-175 has a 14-Mpa compressive strength on day 28 ment has affected vegetation areas and their properties (ASTM C109) shown on Table 1 and 2. (trees, shrubs, grasses, etc.) as these green areas give way to concrete blocks. Urban development reduces the avail- Table 1. Concentrate material codes ability of green areas (Kiran et al., 2005). Hardened areas in buildings such as roofs, walls, balconies, and other areas can be transformed into plant vegetation areas and replace the grounded vegetation into a more sustainable building (Johnston & Newton, 1993). Plants that are grown on, up, or against internal or external walls of buildings or as free- standing structures are called vertical greenery (Mansor et al., 2017). One building in Newbury changed its façade from basic concrete (which is considered dull and unattractive) to vertical greenery, positively improving the aesthetic performance of the building and improving air quality (Ord, 2017). To create successful vertical greenery, the plant must be chosen carefully. Several plants hold their own soil 38

Table 2. Concentrate mixtures The maximum strength value of TM III on day 28 was 26 Mpa. Previous studies have found that TM III can reach 14.5 Mpa on day 28 (Dawood & Ramli, 2008). The current test showed that the pre-vegetated concrete panel of TM III had a lower result on day 28 than the non-prevegetated concrete panel, which had 21.74 Mpa (Figure 5). The methods of producing concrete can be seen in Figure 2. The most crucial dimension of the concrete panel is its thickness, due to the inner and outer systems that are asso- ciated with strength. The dimensions in this research are 50 cm (W) and 8 cm (T). The surfaces were designed to provide more comprehensive results Figure 5. Radiation efficiency versus substrate thickness Figure 2. Methods of producing concrete panels and cubes Figure 6. Compressive strength comparison of standard K-175 and trial mixes Result and Discussion Conclusion The maximum strength of TM I was 33.15 Mpa on day 28. Previous studies have found that TM I can reach 27.6 Mpa The present work characterizes the performance of pre-veg- on day 28 (Berry et al., 2009). The current test showed that etated and non-pre-vegetated concrete panels. The study the prevegetated concrete panel of TM I on day 28 had a utilized the concrete standard for characterization, which lower result than the non-pre-vegetated concrete panel, allows for a comparison to pre-vegetated concrete. The which had 29.84 Mpa (Figure 3). results of the study indicate that pre-vegetated concrete panels have properties that compare with or surpass that Figure 3. Graphic of compressive strength results of non-pre- of non-pre-vegetated concrete panels as nonstructural vegetated and pre-vegetated concrete cubes using Trial Mix I on days concrete. Among three trial mixes chosen, it was found 7, 14, and 28 that TM I (a mixture of fly ash) had the highest compressive The maximum strength value of TM II on day 28 was 26.68 strength on pre-vegetated and non-prevegetated concrete Mpa. Previous studies have found that TM II can reach 14.5 panels. In conclusion, as a nonstructural concrete panel, all Mpa on day 28 (ASTM C109). The current test showed that the trial mixes matched the standard of K-175, surpassing the prevegetated concrete panel of TM II had a lower result 14.5 Mpa in compressive strength. Further investigation is on day 28 than the non-pre-vegetated concrete panel, needed to provide a wide range of structural concrete that which had 21.74 Mpa (Figure 4). can be used in prevegetated concrete panels. Figure 4. Graphic of compressive strength results of non-pre- Acknowledgement vegetated and pre-vegetated concrete cubes using Trial Mix II on days 7, 14, and 28 The authors gratefully acknowledge the Research and Development Division of Wika Beton Inc. for their support on the concrete panels, samples, and funding of the research project. References 1. Johnston, J., Newton, J., 1993. Building Green: A Guide for Using Plants on Roofs, Walls, and Pavements. The London Ecology Unit, London 2. Kiran, C., Mamata, P., Raghunathan, M., 2005. Understanding Environment. Sage Publications, London. 3. Mansor, M., Zakariya, K., Harun, N.Z., Bakar, N.I.A., 2017. Appreciation of Vertical Greenery in a City as a Public Art. Journal of the Malaysian Institute of Planners, Volume 15(1), pp. 117–128 39

Effect of Cooling Rate and Neodymium Addition on Beta Intermetallic Phase of Al-Fe-Si Ternary System Deni Ferdian K. Saputra Irawan, J. Lacaze Department of Metallugical and Materials Engineering Published in: and 443 Si grade) and Al-Fe alloy (made from Al ingot and Transactions of the Indian 80 Fe-Hoesch alloying tablet) were used to synthetize an Institute of Metals Al-7Si-1Fe alloy by melting in a graphite crucible under ambient air. The chemical composition of the master alloy is SJR : 0.36 Q2 (2017) listed in Table 1. Rare earth element was added using a high H index : 19 purity binary Al-Nd alloy to achieve the desired content IF : 0,910 (2017) of 0.3, 0.6 and 1 wt% Nd. The melting fumace being set at 720 °C, the molten metal was unsure homogenization. Abstract Finally, the slag was removed prior pouring into the mould. Unfortunately, Nd addition could not be measured due to Aluminium silicon alloys are widely used in automotive limitation with the optical emission spectrometer apparatus industry and other structural application. However, the that was used. The alloy was then subjected to simul- presence of high content of iron element in Al-Si alloys taneous thermal anal y sis with a PerkinElmer ST A6000 lead to precipitation of beta intermetallic phase that bas a apparatus for differential scanning calorimetry (DSC) anal- detrimental effect on mechanical properties. Reducing the ysis. The runs were performed with cooling rate of 5, 10 adverse effects of-Al9Fe2Si2 precipitates can be achieved and 30 °C min-1 under nitrogen. The DSC samples were by altering their morphology by adding element modifier then prepared for metallographic observation by grinding and increasing solidification cooling rate. In this present with abrasive papers of decreasing size and finally polishing work, simultaneous thermal analysis was used to study the with 0.05µm alumina suspension in alcohol. Metallographic effect of cooling rate (5, 10 and 30 °C min-1) on beta phase analysis was carried out using optical microscopy (Olympus formation in Al-7Si-1Fe alloy added with neodymium at BX 51) and scanning electron microscopy (FEI Inspect F50) 0.3, 0.6 and 1 wt%. The beta phase precipitates were then equipped with energy-dispersive spectrometry (EDAX). characterized using optical microscopy and scanning elec- Moreover, 2D image analysis of backscattered electrons tron microscopy equipped with EDS. Image analysis results (BSE) was carried out using image software for beta phase showed the reduction in size of beta intermetallic phase length analysis. as a result of the rare earth addition. Further analysis also showed the refinement of eutectic silicon Table 1. Chemical composition of Al-7Si-1Fe alloys (wt%) Keywords: Neodymium • Cooling rate • Beta intermetallic Result and Discussion phase • Al-Si alloys Figure 1 illustrates the DSC thermograms for the three Introduction selected cooling rates in the case of the alloy without Nd addition. DSC thermograms show a three-step solidifi- Aluminium silicon alloys are mainly used due to their supe- cation reaction consisting of nucleation and growth of riority in manufacturing process especially lightweight primary (Al) dendrites (a), then precipitation of the beta characteristic, casting fluidity and heat treatability with phase (b) and finally of (Al)-silicon eutectic (c). A shifting of magnesium or copper addition. Nevertheless, in the pres- the thermal arrests to lower the temperature is observed as ence of impurities such as iron element, it will form ironrich the scanning rate increases. intermetallic phase such as beta phase β(-Al9Fe2Si2) which is detrimental to the mechanical properties. The forma- Figure 1. DSC thermograms upon cooling at various scanning rates tion of beta phase is highly influenced by the cooling (green line: 5 °C min-1; blue line: 10 °C min-1; red line: 30 °C min-1) process of solidification (Ferdian et al.), and some elements such as manganese favour the formation of alpha cubic α-Al15(Fe,Mn)3Si2 phase instead of beta phase. Also, rare earth elements are known to modify the eutectic silicon. Furthermore, other studies show their influence on the morphology of beta phase as seen in the work by Li et al. who used La and Y and Rao et al. with samarium. Nevertheless, the use of neodymium as beta phase modi- fier has not been reported. Therefore, the objective of this present work is to characterize the effect of neodymium (Nd) on the beta phase morphology in high purity Al-Fe-Si temary system. Methodology High purity (99.5%) Al ingot, Al-Si alloy (made from Al ingot 40

Figure 2 compares the DSC thermograms recorded at 30 °C min-1 for the alloys without and with Nd additions. Addition of Nd slightly shifts the temperature for beta phase formation from 566 to 565 °C. A shift is also noticed for the (Al)-Si eutectic from 552 °C without Nd to 548 °C with 1 wt% Nd. Figure 2. DSC Figure 4.Evolution with the Nd content of beta phase length in DSC thermograms upon samples cooled at 30 °C min-1: a beta phase maximum and average cooling at 30 °C length (blue line: maximum, red line: average). b Distribution of beta min-1 for various phase length neodymium additions Conclusion EDS mapping and micro-chemical analysis as seen in Figure3 indicate the formation of an intermetallic compound Rare earth addition to an Al-Fe-Si alloy reduces the beta containing neodymium. Increasing the neodymium content phase average length. Reduction achieved amounts to reduces the maximum length of the five largest parti- 20% with 1% Nd addition (from 202 µm to 145 µm). The cles from 290 µm without Nd addition to 206 µm with 1 results also show the refinement of eutectic silicon with Nd %wt Nd, i.e. approximately 30% reduction. At the same addition. time, the average beta phase length decreases from 202 to 145 µm. Figure 4 shows the length distribution of the References beta phase, where the addition of Nd shifts the beta phase length distribution to a lower range. Without any addition 1. Barrirero J, Engstler M, Ghafoor N, de Jonge N, Odén of Nd, the minimum length of beta particles is over 150 M, and Mücklich F, J Alloys Compd 611 (2014) 410 µm and 20% of the beta precipitates are over 250 µm. By adding 1% Nd, very few beta particles are larger than 200 2. Ferdian D., Suharno B., Duployer B, Duployer B, µm and 13% have a size below 100 µm. The size reduc- Tenailleau C, Salvo L, and Lacaze J, Trans Jndianlnst tion mechanism by Nd addition can be promoted by the Met 65 (2012) 821. blocking the Si and Fe atoms during the beta phase growth. Furthermore, the addition of Nd reduces the length of 3. Li Z, and Yan H, J Rare Earths 33 (2015) 995. eutectic silicon. Increasing the neodyrnium reduces the average length of eutectic silicon from 35 µm without any 4. Lu S Z, and Hellawell A. Metall Trans A 18 (1987) 1721. addition to 14 µm with 1 % Nd addition. This reduction can be explained by impurity-induced twinning mechanism 5. Rao Y, Yan H, and Hu Z, J Rare Earths 33 (2013) 916. as originally suggested by Lu and Hellawell and confirmed more recently by Timpel et al.and Barrirero et al. According 6. Timpel M, Wanderka N, Schlesiger N, Yamamoto T, to these authors, the twins grow when the atomic size ratio Lazarev N, of the modifier element with silicon is high enough, which is the case with Nd element for which the atomic size ratio 7. Isheim D, Schmitz G, Matsumura S, and Banhart J, Acta is 1.55. Mater 60 (2012) 3920. Figure 3 Backscattered electrons SEM micrograph of Al-7Si-1Fe-1Nd alloy (a) and related EDS mappings of aluminium (b), silicon (c), iron (d) and neodymium (e) 41

Effect of Coating Layer of Sand Casting Mold in Thin- Walled Ductile Iron Casting: Reducing the Skin Effect Formation Donanta Dhaneswara Bambang Suharno, Rianti Dewi S. Ariobimo, Djodi Budi Sambodo, Jaka Fajar Fatriansyah Department of Metallugical and Materials Engineering Published in: layers which may give different cooling rate to observe the International Journal of skin effect and thin-walled ductile iron microstructures. Metalcasting However, in this paper, we do not discuss mechanical prop- erties of thin-walled ductile iron and merely inferring the SJR : 0.33 Q2 (2017) possibility of mechanical properties behavior based on H index : 11 microstructures observation. IF : 0,779 (2017) Methodology Abstract The design of this experiment was based on a design The effect of various coating layers on the skin effect used by Riantiet al.11 using 1-mm-thick plates. Five plates formation in thin-walled ductile iron casting with glass wool were arranged parallel to each other. The experiment was heat insulator has been investigated. Graphite, MgO, Zr, Zr conducted in foundry-based industry. Casting products + graphite, MgO + graphite coating layers have been used. were numbered from 1 at the ingate consecutively to 5 at We observed that the different coating layers can be used the riser. Heat insulator glass wool was placed in the left to control cooling rate. Higher heat conductivity coating and right side of casting (inside the mold) with a thickness layer yields lower cooling rate, while lower heat conduc- of 40 and 50 mm, respectively, with the distance of 20 tivity yields higher cooling rate. The use of double layer can mmfrom thin-walled ductile iron casting. The design sche- further increase cooling rate which was observed for Zr + matic is shown in Figure 1. Here, we only consider product graphite and MgO + graphite double coating layers. These which is made at plate number 3 may only be applicable in our system. Higher cooling rate system produces a casting product that has thinner skin Figure 1.Schematic of casting design. (a) Front view. (b). Side view. effect. The use of MgO layer yields lower skin effect thick- (c). Top view. (d). Plate 3 crosssection 1. Down-sprue. 2. Runner. 3. ness which stood at 52.27 µm. Ingate. 4. Riser. 5. Plate. 6. Gas Tunnel. 7. Isolator (glass wool). Keywords: Thin-walled ductile iron;Coating layers;Cooling Result and Discussion rate The skin layer effect of one of samples is given in Figure Introduction 2 (d, t and l indices mean the edge near sprue side, center and the edge opposite of sprue side, respectively, of In the automotive industry, increasing fuel efficiency and testing points), and the microstructure of the samples was reducing emissions are some of the important challenges. observed with non-etching procedure and 1009 magnifica- One of the solutions for these challenges is the develop- tion and is shown in Figure 3. ment of lighter parts for automotive/vehicle components. In order to alleviate the cost problem while at the same Figure 2.Skin layer time using lighter components, thin-walled ductile iron effect example in one casting can be used as alternative due to the its properties of our samples that not only fulfill the criteria for lower weight than usual cast iron, but more importantly it is cheaper than aluminum casting. Moreover, thin-walled ductile iron brings better performance for high temperature and higher strength to weight ratios.1 One of the keys of controlling the skin effect thickness is the cooling rate as suggested by Aufderheiden et al.7 The use of a heat insulator for controlling the cooling rate on thin- walled ductile iron has been conducted by Dhaneswara et al.10 They used ceramic fiber as heat insulator and found out that the cooling rate decreased. In that case, even the skin effect still took place, maybe due to the lower cooling rate, the mechanical properties of thin-walled ductile iron were greatly improved due to less nodularity. The use of coating layers in molding case can also be used to control the cooling rate by giving the additional heat conductivity layer. In this paper, we use glass wool as heat insulator and MgO, graphite and Zr, MgO ? graphite, Zr ? graphite as coating layers. We investigate the effect of using different coating 42

Figure 3.Non-etching and 1009 magnification of microstructure Figure 4.The relation between skin effect thickness and cooling rate. observation. d, t and l indices mean the edge near sprue side, center and the edge opposite of sprue side, respectively, of testing points Conclusion Then, we discuss the percentage of nodularity in our Some conclusions can be drawn from our experiments: samples. Percentage of nodularity was found to be highest The use of glass wool as heat insulator may not prevent the for C (Zr) sample which stood at 83% and to be lowest formation of skin but may change the cooling rate. The use for B (graphite) sample which stood at 76%. However, of various coating layers can be used to control cooling rate. these values do not correlate with other variables. The Generally, higher heat conductivity coating layer yields low percentage of nodularity actually is related to the spheroid- cooling rate. In addition, the use of double layer for coating izinand antispheroidizing elements which are not variables can enhance cooling rate. The use of MgO layer yield lower in our experiment. All of our samples use similar inocu- skin thickness which stood at 52.27 lm. lant and relatively similar materials except coating layers. So the different coating layers may not drastically change Graphite coating layer sample has lowest nodule count the percentage of nodularity. However, the percentage at 452 per mm2. The formation of carbide occured for of nodularity of our samples is quite high which may lead Zrgraphite and E MgO-graphite coating layer samples which to the better mechanical properties as demonstrated by have CE[4,3% although it is not observed in Zr coating layer AlGhonamy et al. They found that the higher percentage sample even though this sample has similar CE. Percentage of nodularity leads to higher strength, impact strength and of nodularity is foun elongation tests. Non-etching and 10009 magnification of microstructure observation pictures are given in Figure 6. Acknowledgement d, t and l indices mean the edge near sprue side, center and the edge opposite of sprue side, respectively, of testing Authors thank the Indonesian government for research points. funding. Authors also thank GetekaFourindo company which allowed us to conduct our experiment in its factory. Generally, higher cooling rate yields thinner skin effect except for MgO coating layer which is exceptionally excel- References lent reducing skin effect despite its relatively high cooling rate. We suggested that a chemical reaction occured 1. M. Caldera, M. Chapetti, J.M. Massone, J.A. Sikora, Influence of that Mg may prevent the formation of skin. Maybe more nodule count on fatigue properties of ferritic thin wall ductile iron. research needs to be done for investigating MgO as coating Mater. Sci. Tech. 23, 1000–1004 (2007) layer. To close the discussion, however, the addition of glass wool heat insulator may not prevent the formation of skin 2. R.A. Martinez, R.E. Boeri, J.A. Sikora, Application of ADI in high but may change the cooling rate. strength thin wall automotive parts, in Proceedings of the 2002 World Conference on ADI. AFS (2002) (pp. 144–148) 4 3. D.M. Stefanescu, L.P. Dix, R.E. Ruxanda, C. CrobittCoburn, T.S. Piwonka, Tensile properties of thin wall ductile iron. AFS Transactions, 110 (2002) 4. J.W. Soedarsono, R.D. Sulamet-Ariobimo, Effect of casting design to microstructure and mechanical properties of 1 mm thin walled ductile iron plate, in Applied Mechanics and Materials, Vol. 110 (Trans Tech Publications, 2012) pp. 3301–3307 5. H. Reisener, Some aspects of the formation and structure of a skin on iron castings and a method used to obviate its occurrence. The British Foundryman, (1962) pp. 362–369 6. R.C. Aufderheide, R.E. Showman, M.A. Hysell, 05-043 controlling the’’ skin effect’’ on thin-wall ductile iron castings. Trans.-Am. Foundrym. Soc. 113, 567 (2005) 7. R.E. Ruxanda, D.M. Stefanescu, T.S. Piwonka, Microstructure char- acterization of ductile thin-wall iron castings. Trans.-Am. Foundrym. Soc. 2, 1131–1148 (2002) 43

Performance Test of 2.5 kW DC Boost Converter for Nanogrid System Applications Eko Adhi Setiawan Jamsep Andreas, Suharsono Halim, Muhamad Atar, Hanifati Nur Shabrina Department of Electrical Engineering Published in: International Journal of Technology SJR : 0.26 Q2 (2017) H index : 6 IF : - Figure 1.DC boost converter basic circuit Abstract Methodology The development of power electronics continues to grow Figure 2 show the design of a DC boost converter system. rapidly. One type of power electronics is the DC boost It is divided into four main parts; first is a microcon- converter, which steps up DC voltage to another level. DC troller that acts as a control center converter to keep the boost converters are widely used in many applications; for output voltage stable at a nominal desired voltage – in this renewable energy, DC boost converters are very useful for research, 235 VDC. stepping up DC voltage levels from nonconventional energy resources, such as photovoltaics, wind turbines, and fuel Figure 2.DC boost converter block diagram cells, to the main system. In this study, we tested a DC boost Performance tests of the converter were conducted converter that has been developed to step up 48 VDC from to determine voltage stability and efficiency. The test energy storage to 235 VDC in the main bus. The DC boost involved supplying a load to the converter (loads shown in converter will be used in the nanogrids system, developed Table 2) over the course of 3 hours, gradually increasing by TREC and will supply household appliances such as tele- and decreasing from 0–2500 W. This test could assess the visions, lamps, laptops, and mobile phones. The performance performance of the converter for each load because the tests showed between +3% and -1.2% of voltage deviation total testing load was close to the capacity of the converter. and 66– 98% efficiency. In this test, the voltage output of the converter was set to 235 VDC. The test measured the input and output voltage Keywords: DC boost; Efficiency; Nanogrids; Performance test and current of the converter using an oscilloscope and multimeters. The input voltage source for the test was a Introduction 48 V DC power supply. Figure 3 shows the performance test setup of the converter. The test was conducted by A DC-DC converter converts directly from DC voltage to capturing the input and output voltage and current every another level of DC voltage. DC-DC converters are widely minute. used for many applications, such as traction motor control in automobiles, trolley cars, marine hoists, forklift trucks, and Table 2. mine haulers, to provide smooth acceleration control, high Performance efficiency, and fast dynamic response (Rashid, 2004). DC-DC test loads converters are divided into two main types: hard-switching pulse width modulated (PWM) converters and resonant, soft- switching converters. PWM converters are currently more commonly used because they have high efficiency, simple operational control, and a simple topology that uses fewer components. However, PWM converters experience signifi- cant losses at high switching. DC Boost Converter Figure 1 shows the basic circuit of a DC boost converter. When the switching component is in the closed position (on state), the current in the inductor will be stored and the current of IL will increase linearly. The diode will be in the reverse bias condition because the inductor voltage isgreater than output voltage. When the switching component is in the open posi- tion (off state), the energy stored in the inductor will flow to the load. The current will pass through the diode into the capacitor and resistor because the diode is in the forward bias condition and assumes no voltage drop in the diode. In steady state and continuous conduction mode, the total change in the induced current must be zero. 44

Figure 3.Set up of performance test DC boost converter Based on the calculations, the more load that was supplied, the more current was output and the greater the losses. Result and Discussion Therefore, when load was supplied, efficiency decreased. However, this is not seen in the efficiency graph: converter The results of the test are shown in Figures 4 and 5, repre- efficiency decreased when the load or current were low. sented as voltage and efficiency graphs. In this test, the This is due to standby losses, which occur when the elec- highest output voltage was 242 VDC and the lowest was tronic components in the converter were activated before 232 VDC, for a voltage deviation + 3% and -1.2% The converting the voltage. Standby losses were constant with average output voltage during the test was 235.15 VDC the loads supplied, and were generated by the converter with a difference 0.15 V, which was 0.06% from the voltage under a no-load condition. At low load, standby losses can setting. The voltage deviation occurred when loads were be very significant, resulting in converter efficiency in the charged and discharged from the converter. When the load range of 66–72%. At high loads, standby losses are not was supplied, the current output increased, causing the significant and affect efficiency only slightly. output voltage converter to sag for a short time; conversely, when the load was discharged, the current decreased, Table 3 shows the specifications and components of the resulting in a momentary output voltage swell. The insta- Dual Power system. The DC source of the Dual Power bility of the output voltage in both conditions was due to system is composed of PV arrays, charge controllers, the PI controller settings in the converter. batteries, and a DC boost converter. Figure 8 shows the layout of the Dual Power topology, implemented with all components combined in a panel box, as the control and protection center of the system. Table 3.Dual power implemented specifications Figure 4. Voltage ratio againts supplied loads Conclusion The two graphs in Figures 4 and 5 refer to the same period The performance test of this converter achieved very of time. In the efficiency measurement, the efficiency of stable output with +3% and -1.2% voltage deviation. The the converter was 66–98%. The efficiency saturated at average output voltage was 235.15 V, with a difference 93–98% when the loads were 930 W and above. There are of 0.15 V or 0.06% from the setting value, meaning that several elements that affect efficiency – switching losses the output voltage of the converter was quite stable. The and conduction losses that are generated by switching converter efficiency in this test was 66–98%. The low effi- components, caused by the IGBT, and which depend on the ciency was affected by significant standby losses to the temperature when the IGBT engages in switching activity, load supplied, while at high loads – above 930 watts – the and conduction losses, which can be calculated using converter efficiency was stable at 93–98%. This indicates on-state current and voltage. In IGBT, the losses are due that the converter already has good efficiency for use in to RDS(on) resistance and depend on the temperature. The Dual Power, a new concept for nanogrid systems. rectifier diode also contributes to conduction losses, due to the dissipation of the output current. Acknowledgement Figure 5.DC boost converter efficiency during performance test This paper was supported and funded by the Hibah Program Pengembangan TeknologiIndustri/ PPTI of the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia, grant number 03/II/PPK/E/ E4/2018. References 1. Adda, R., Ray, O., Mishra, S., Joshi, A., 2012a. Implementation and Control of Switched Boost Inverter for DC Nanogrid Applications. In: 2012 IEEE Energy Conversion Congress and Exposition (ECCE), Raleigh, 15-20 September, USA, pp. 3811–3818. 2. Blaabjerg, F., Ma, K., 2013. Future on Power Electronics for Wind Turbine Systems. IEEE Journal of Emerging and Selected Topics in Power Electronics, Volume 1(3), pp. 139–152 3. Rashid, M.H., 2004. Power Electronics: Circuits, Devices, and Applications (3rd Edition). Pearson, USA. 45

Anti-amoebic activity of acyclic and cyclic-samarium complexes on Acanthamoeba Eny Kusrini Fatimah Hashim, Cindy Gunawan, Riti Mann, Wan Nor Nadhirah, Wan Noor Azmi, Nakisah Mat Amin Department of Chemical Engineering Published in: vitro anti-amoebic activity of samarium complexes with Parasitology Research acyclic (pentaethylene glycol, EO5) and cyclic (18-crown-6, 18C6) structures. Two samarium complexes of acyclic SJR : 0.99 Q1 (2017) [Sm(Pic)2(EO5)](Pic) and cyclic [Sm(Pic)2(18C6)](Pic) struc- H index : 79 tures were investigated in this study for their activity IF : 2.558 (2017) against a clinical isolate of Acanthamoeba. Abstract Methodology This work investigated the anti-amoebic activity of two The Acanthamoeba was cultivated in PYG medium, samarium (Sm) complexes, the acyclic complex [bis(picrato) prepared by mixing 6.5 g protease, 6.5 g yeast, 15 g D+ (pentaethylene glycol) samarium(III)] picrate—referred to glucose, and making up to 1000 mL final volume using as [Sm(Pic)2(EO5)](Pic)—and the cyclic complex [bis(pi- Page amoeba solution (PAS). Determination of IC50 crato)(18-crown-6)samarium(III)] picrate—referred to as values of acyclic and cyclic Sm complexes by MTT assay [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morpho- on Acanthamoeba. Microscopy study of Acanthamoeba logical transformation of the protozoa Acanthamoeba from treated with acyclic and cyclic Sm complexes. Analysis of its native trophozoite form carrying a spine-like structure DNA damage by alkaline comet assay. Autodock version called acanthopodia, to round-shaped cells with loss of the 4 with the latest Lamarckian genetic algorithm (LGA) was acanthopodia structure, a trademark response to environ- employed to visualize the interactions between the Sm mental stress. Further investigation, however, revealed complexes with a target protein. that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic Result and Discussion complex (0.7 μg/mL) was 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the The effect of the acyclic and cyclic Sm complexes on Acanthamoeba with the acyclic complex caused apop- Acanthamoeba’s viability tosis of the treated cells, while the treatment with the Presence of 0.7 μg/mL (IC50) of the acyclic Sm complex cyclic complex caused necrosis evident by the leakage of already killed ~50% of the Acanthamoeba, while the 30 the cell membrane. Both treatments induced DNA damage μg/mL exposure almost completely eradicated the cells in Acanthamoeba. Finally, a molecular docking simulation (Fig 1a). Exposure to the cyclic Sm complex resulted in less revealed the potential capability of the acyclic complex to extent of the anti-amoebic activity, with ~ 50% non-viable form hydrogen bonds with profilin—a membrane protein cells detected at 6.5 μg/mL (IC50), while further increasing present in eukaryotes, including Acanthamoeba, that the treatment dosage to 15 μg/ mL saw ~ 85% non-viable plays important roles in the formation and degradation of cells (Fig. 1b). actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at Figure 1 Cell viability least in part, for the much higher cytotoxicity of the acyclic of Acanthamoeba complex and also possibly, for the observed differences following treatment in the cytotoxicity traits. Nonetheless, with IC50 values with increasing of < 10 μg/mL, both the acyclic and cyclic Sm complexes concentrations feature a promising potential as cytotoxic agents to fight of a the acyclic amoebic infections. Sm(Pic)2(EO5)](Pic) and b the cyclic Introduction [Sm(Pic)2(18C6)](Pic) complexes at 30 °C The ubiquitously present free-living amoebic protozoa for 24 h. belonging to the genus Acanthamoeba are the etiological agents of prominent diseases like amoebic keratitis (infec- tion of the eye) and granulomatous amoebic encephalitis (fatal disease of the central nervous system) (Marciano- Cabral and Cabral 2003). Lanthanides have found applications as diagnostic and prognostic probes in clin- ical laboratories Their use as an anticancer agent is also rising (Misra et al. 2004). To further expand the antimi- crobial spectrum of lanthanides, this study reports the in 46

Morphological changes and modes of cell death of the Sm the embedded presence of Thr35, Ser1, 3, and 6 residues, complexes-treated Acanthamoeba while the Sm3+ ion was found only on the surface of the Under the light microscope, untreated cells showed the protein. The docking simulation revealed the inability of the presence of Acanthamoeba trophozoites or vegeta- cyclic Sm complex to form hydrogen bond with the amino tive cells with the characteristic presence of spine-like acid residues due its rigid and cyclic conformation. structures called acanthopodia on their surface (Fig. 2a). Exposure to both acyclic and cyclic Sm complexes resulted Conclusion in the loss of the acanthopodia structure, transforming the Acanthamoeba into round-shaped cells (Fig. 2b, c). In summary, we reported the anti-amoebic activity of Sm Exposure of the Acanthamoeba to acyclic Sm complexes at complexes, both in the acyclic [Sm(Pic)2(EO5)](Pic) and 50% IC50 dosage resulted in plasma membrane disruption cyclic [Sm(Pic)2(18C6)](Pic) forms against Acanthamoeba. in minor fraction of the cell population, visibly indicated by Although the two forms were capable of inducing DNA the occurrence of orange fluorescence entities in these cells breaks, the acyclic Sm complex, however, exhibited higher (with the majority of the cells still with intact membrane level of cytotoxicity with IC50 of 0.7 μg/mL compared to emitting green fluorescence) (Fig. 2e). This is in contrast the cyclic form with 10-fold higher IC50 concentration. to the untreated cells, all visible as green fluorescence Investigated at their 50% IC50 dosage, both acyclic and cells and therefore, indicating healthy cells with intact cyclic Sm complexes induced the loss of the acanthopodia plasma membrane (Fig. 2d). We also observed swelling of structure, commonly present in healthy Acanthamoeba. the Acanthamoeba organelles (enlarged cell shown in the A more detailed microscopy study, still at the 50% panel, Fig. 2f), which is commonly reported with necrotic IC50 dosage, revealed the occurrence of early apop- cells (Murakami et al. 2011). totic Acanthamoeba cells in the acyclic complexestreated samples. Assessed at its 50% IC50 dosage, the cyclic Sm Figure 2 (a) The untreated Acanthamoeba, (b) The acyclic Sm complex on the other hand induced the necrosis phenom- complex-treated Acanthamoeba, (c) The cyclic Sm complex-treated enon on the Acanthamoeba, with the trademark release of Acanthamoeba, (d) The untreated Acanthamoeba stained with AO/PI cellular constituents. Such differences in the extent and dyes showed green fluorescent cells, (e) Acanthamoeba treated with mechanisms of cytotoxicity could due to, at least in part, the acyclic Sm complex fluoresces yellow, (f) Acanthamoeba treated the potential capability of the acyclic Sm complex to form with the cyclic Sm complex fluoresces red. hydrogen bonds in the hydrophilic pockets of the membrane protein profilin, unlike the Sm cyclic complex. Revealed by The acyclic and cyclic Sm complexes-induced DNA damage a molecular docking simulation, this interaction could ulti- The potential of the acyclic and cyclic Sm complexes to mately disrupt the Acanthamoeba’s shape and movement. cause DNA damage on Acanthamoeba was studied with the alkaline comet assay. The versatile assay is consid- Acknowledgement ered sensitive for assessing single- and double-strand DNA breaks in cells (Tice et al. 2000). These findings of DNA The authors wish to thank the Universiti Malaysia strand breaks are consistent with the earlier mentioned Terengganu (UMT) for providing the Acanthamoeba. We early apoptotic DNA fragmentation (with the AO/PI would also like to thank Intan Nursuraya for her assistance double staining) observed with the acyclic complex-treated with the in silico molecular docking calculation. samples (Fig. 2e). As with the cyclic Sm complex, it appears that the induced necrosis cell death (Fig. 2f) was also asso- References ciated with DNA strand breaks. Molecular docking simulation of the acyclic and cyclic Sm 1. Marciano-Cabral F, Cabral G (2003) Acanthamoeba complexes on Acanthamoeba’s profilin protein. spp. as agents of disease in humans. Clin Microbiol Rev An in silico molecular docking simulation was carried out 16:273–307 to investigate the binding affinities of the acyclic and cyclic Sm complexes on an Acanthamoeba protein, the profilin 2. Misra SN, Gagnani MA, ID M, Shukla RS (2004) 1B (PDB ID: 1ACF). The docking simulation revealed inter- Biological and clinical aspects of lanthanide coordina- actions of the acyclic Sm complex with specific regions in tion compounds. Bioinorg Chem Appl 2:155–192. profilin 1B. The interactions were found to occur in hydro- philic pockets of the profilin, in the form of hydrogen 3. Murakami Y, Miller JW, Vavvas DG (2011) RIP bonding of the acyclic pentaethylene glycol (EO5) with kinase-mediated necrosis as an alternative mechanisms of photoreceptor death. Oncotarget 2:497–509. 47

Production of Dry Extract Lipase from Pseudomonas Aeruginosa by The Submerged Fermentation Method in Palm Oil Mill Effluent Heri Hermansyah Ambar Maresya, Dwini Normayulisa Putri, Muhamad Sahlan, Michel Meyer Department of Chemical Engineering Published in: In this study, cultures of Pseudomonas aeruginosa were ternational Journal of grown in POME to produce lipase using the submerged Technology fermentation method, and the cell free supernatant was then dried to obtain dry extract lipase. In order to improve SJR : 0.26 Q2 (2017) lipase production, the one factor at a time (OFAT) method H index : 6 was applied to investigate the influencing factors in lipase IF : - production. OFAT is a method in which the experimental factors are varied one at a time, with the remaining factors Abstract held constant. Palm Oil Mill Effluent (POME) is an agro-industrial waste Methodology product with high availability and which contains high quan- tities of organic compounds that are necessary for microbial Preparation of the inoculum was made by suspending growth. Cultures of Pseudomonas aeruginosa were grown Pseudomonas aeruginosa from nutrient agar in 50 ml of in POME to produce lipase using the submerged fermen- sterile Luria Bertani broth using a sterile inoculating loop, tation method. The objective of this study is to obtain the and incubating it using a water shaker bath at 170 rpm and optimum value of lipase activity produced by the cultures 30oC for 24 hours. The mixture was then used as the inoc- of Pseudomonas aeruginosa using POME as the substrate ulum in further experiments. through the submerged fermentation method and to obtain the dry extract of lipase. In the study, the one factor The optimization of the medium was made using the one at a time (OFAT) method was applied, which allowed obser- factor at a time (OFAT) method. In this way, the experi- vation of the effect of inoculum and additional nutrient mental factors were varied one at a time, while the other concentrations, such as Ca2+ ion, olive oil, peptone and factors were kept constant. The medium for the lipase Tween 80, on the activity of lipase. These factors were production was prepared using sterilized POME as the investigated in shake flask fermentation at 30oC over 96 basal medium, which contained olive oil (0.1–0.2%, v/v), hours. The activity unit of lipase was determined by the peptone (0.3–1.1%, w/v), CaCl2.2H2O (4.0–12.0 mM) and titrimetric reaction of olive oil hydrolysis using crude lipase. Tween 80 (0.3–1.1%, v/v). The optimum value of the lipase activity unit (1.327 U/mL) was gained when 3% (v/v) of inoculum, 4 mM of Ca2+ ion, The lipase activity was assayed by alkali titration using 0.4% (v/v) of olive oil, 0.9% (m/v) of peptone, and 0.9% of olive oil as the substrate with several modifications in the Tween 80 were added into the medium. Crude lipase was titration method. Scale-up production was conducted in then dried using a spray dryer. Subsequently, 15.643 g of a 30-L bioreactor with two six-flat-blade impellers. The dry extract lipase was obtained from 500 mL of cell free bioreactor was filled with 20-L of POME as the basal supernatant. In further research, the lipase activity assay medium, containing the optimum concentrations of olive would be better achieved using the p-nitrophenyl palmitate oil, peptone, CaCl2.2H2O and Tween 80 obtained from the hydrolysis method and examined by a spectrophotometer. OFAT method. Keywords: Activity unit; Lipase; Palm oil mill effluent; Result and Discussion Submerged fermentation In this experiment, growth of Pseudomonas aeruginosa Introduction and lipase activity was observed (Figure 1). The cells grew rapidly at the beginning because the nutrients in Lipase is an enzyme which catalyzes the hydrolysis reac- the medium were still at a high level. The cultures then tion of triglycerides into fatty acids and several types of reached the stationary phase because the nutrients in the glycerol, including di-acylglycerol and mono-acylglyc- medium were limited, which caused cell growth restric- erol). Recently, lipase has attracted significant interest tion (Yates & Smotzer, 2007). After 96 hours above, culture for commercial production, as it has several advantages, growth decreased and reached the death phase because including the fact that no cofactor is required, it is active in the environment no longer supported any growth (Yates & the interfaces of organic compounds, and facilitates a wide Smotzer, 2007), such as the lack of nutrients and oxygen in range of substrates. Submerged fermentation is one of the the medium. In submerged fermentation, consumption of fermentation methods that have been used by industry for oxygen is proportional to the conversion of the substrate example in enzyme production, due to the better control into the product. of the parameters that affect the yield of the product, temperature, pH and agitation are well-established for In this experiment, growth of Pseudomonas aeruginosa scaling the processes for industrial production capacity and lipase activity was observed (Figure 1). The cells (Hansen et al., 2015). grew rapidly at the beginning because the nutrients in the medium were still at a high level. The cultures then reached the stationary phase because the nutrients in the medium were limited, which caused cell growth restric- tion (Yates & Smotzer, 2007). After 96 hours above, culture 48

growth decreased and reached the death phase because n this study, concentrations of 0.2–0.6 % (v/v) olive oil were the environment no longer supported any growth (Yates & investigated. Pseudomonas aeruginosa was shown to have Smotzer, 2007), such as the lack of nutrients and oxygen in the best lipase activity of 0.899 U/ml at 0.4 % (v/v) olive oil the medium. In submerged fermentation, consumption of (Figure 4). oxygen is proportional to the conversion of the substrate into the product. Figure 1. Pseudomonas aeruginosa growth (log OD) and lipase Figure 4. Effect of different concentrations of olive oil on lipase activity (u/mL) in POME activity unit To investigate the influence of inoculum concentration, 1.0–5.0 % (v/v) of inoculum was tested. The highest activity Conclusion of 0.813 U/ml was obtained from 3.0% (v/v) of inoculum concentration (Figure 2). The limited supply of nutrients in The activity unit of lipase from Pseudomonas aeruginosa the medium could cause the inoculum to compete, meaning using POME as the basal medium reached a maximum enzyme production will be affected. value of 1.327 U/mL from the crude form. The optimum values of the lipase activity unit were gained when 3% (v/v) Figure 2. Effect of different concentrations of inoculum on lipase of inoculum, 0.9% (m/v) of peptone, 0.4% (v/v) of olive oil, activity unit 4 mM of Ca2+ ions, and 0.9% of Tween 80 were added into Ca2+ ions from CaCl2.2H2O were also added at a concen- the medium and fermented for 96 hours. The dry extracel- tration of 4 mM–6 mM to investigate their influence. The lular lipase obtained had an activity unit of 28.5 U/g, with highest activity of 0.813 U/ml was obtained from 6 mM a specific activity of 2.417 U/g proteins. The utilization of CaCl2.2H2O (Figure 3). Calcium is an essential element POME as an alternative medium would result in a consider- in cell signalling and is required as a cofactor for many able reduction in the cost of lipase production. The values enzymes. However, a high concentration of calcium ions of the lipase activities would achieve better results if the could be toxic to the cells and decrease growth. experiment used the hydrolysis reaction of p-nitrophenyl palmitate and examination by spectrophotometer. Figure 3. Effect of different concentrations of Ca2+ ions on lipase activity unit Acknowledgement The authors are grateful for the research support provided by Ministry of Research, Technology, and Higher Education through International Research Collaboration Grant Program and for the publication support provided by the United States Agency for International Development (USAID) through the Sustainable Higher Education Research Alliance (SHERA) Program for Universitas Indonesia’s Scientific Modeling, Application, Research and Training for City-centered Innovation and Technology (SMART CITY) Project, Grant #AID-497-A-1600004, Sub Grant #IIE-00000078-UI-1. References 1. Gullo, M., Verzelloni, E., Canonico, M., 2014. Aerobic Submerged Fermentation by Acetic Acid Bacteria for Vinegar Production: Process and Biotechnological Aspects. Process Biochemistry, Volume 49(10), pp. 1571–1579 2. Hansen, G.H., Lübeck, M., Frisvad, J.C., Lübeck, P.S., Andersen, B., 2015. Production of Cellulolytic Enzymes from Ascomycetes: Comparison of Solid State and Submerged Fermentation. Process Biochemistry, Volume 50(9), pp. 1327–1341 3. Yates, G.T., Smotzer, T., 2007. On the Lag Phase and Initial Decline of Microbial Growth Curves. Journal of Theoretical Biology, Volume 244(3), pp. 511–51 49

Deacidification of palm oil using betaine monohydrate- based natural deep eutectic solvents Kamarza Mulia Ida Zahrina, Mohammad Nasikin, Elsa Anisa Krisanti Department of Chemical Engineering Published in: NMR spectroscopy. The H NMR spectra of palm oil feed, Food Chemistry oil-rich phase, and NADES-rich phase were recorded with a JEOL JNMECA 500 NMR spectrometer using chloroform SJR : 1.79 Q1 (2017) as a solvent. H index : 204 IF : 4.946 (2017) Result and Discussion Abstract Distribution coefficient of solutes and selectivity of solvent The distribution coefficient of the solute (ki) and selectivity In the palm oil industry, the deacidify cation process is of the solvent (Si/j) are widely used parameters to charac- performed by steam stripping which causes the loss of terize the suitability of a solvent in liquid-liquid extraction. most of palm oil’s natural antioxidants due to high tempera- The distribution coefficients of solutes (palmitic acid, α-to- ture. The liquid – liquid extraction process which is carried copherol and β-carotene) are shown in Fig. 1, while plot of out at low temperature is preferable in order to preserve selectivity of the solvents tested against the distribution these compounds. The use of hydrated ethanol can reduce coefficients of palmitic acid at an oil-to-solvent volume the losses of antioxidants, but the ability of this solvent to ratio of 1:2 and temperature of 40 °C is shown in Fig. 2 extract free fatty acids also decreases. Betaine monohy- drate-based natural deep eutectic solvents (NADES) have Figure 1 Distribution coefficients of solutes at an oil-to-solvent extensive potential for this process. The selectivity of these volume ratio of 1:2, and a temperature of 40 °C for 2 h: ( ) palmitic NADES was determined to select a preferable solvent. The acid (k1), ( Z ) β-carotene (k2), ( ) α-tocopherol (k3). betaine monohydrate-glycerol NADES in a molar ratio of 1:8 was determined to be the preferred solvent with the Figure 2 Distribution coefficient of palmitic acid vs. selectivity of the highest selectivity. This solvent has an efficiency of palmitic betaine monohydratebased NADES at an oil-to-solvent volume ratio acid extraction of 34.14%, and the amount of antioxidants of 1:2 and temperature of 40 °C for 2 h. can be preserved in the refined palm oil up to 99%. The compounds in palm oil were stable during extraction. Introduction Crude palm oil is very rich in natural antioxidant compounds, suchas carotenes and tocopherols which are beneficial to human health: therefore, most palm oil products are used as edible products (Chuang & Brunner, 2006). Natural deep eutectic solvents (NADES) are recently developed by eutectic mixture of a non-toxic quaternary ammonium salt (such as choline chloride or betaine) and a hydrogen bond donor (HBD) (such as sugars, polyols, and organic acids). Betaine monohydrate is a quaternary ammonium salt that is made as an additional product during the separation process of sucrose from sugar beet (Makela, 2004). NADES that are formed by mixing of the betaine monohydrate and different HBDs (polyol and mixed polyol/organic acid) can be utilized as highly selective solvents for the deacidifica- tion of palm oil by liquid– liquid extraction. Methodology The quantity of palmitic acid was determined according to the official titration method 2201 by the IUPAC (Manic et al., 2011). The oil rich phase was washed with warm water until all traces of NADES were removed, which was tested by qualitative analysis with Jones’ reagent. The quanti- ties of antioxidants were determined by high performance liquid chromatography (HPLC). The stability of antioxidant compounds during extraction process was observed by 50