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331	PHYSICAL SCIENCES	ABS-353
Investigations of Ge Ions and Damage Profiles of Axial-implanted <100> Zinc Blende GaAs Using SIMS and RBS Techniques Imam Rofii1), a), b), Misto1), Edy Supriyanto1), Sujito1), and Mutmainnah1) Authors Affiliation 1) Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), University of Jember, Jl. Kalimantan, 37, Kampus Tegalboto, Jember, East Java, Indonesia, 68121 Author Emails a) Corresponding author: imr.rofii.fmipa[at]unej.ac.id b) imr.rofii[at]gmail.com Abstract In this report, SIMS and RBS techniques were used for determinations of germanium ion and damage profiles of germanium ion implanted into <100> Zinc Blende GaAs. During the ion implantation processes, energetic germanium ion beams were bombarded on the surface of semi insulating intrinsic zinc blende GaAs sample. In theise processes, germanium ion beam entered the zinc blende GaAs crystal structure and underwent multiple scattering with the atomic hosts (Ga and As ions) before stopping. At the stopping points, these germanium ions can stay in the GaAs crystal unit cells by replacing either Ga or As host ions. If the germanium ions stay in the Ga ion positions, the Ge ions would act as donor ions. Otherwise if its stay in the As ion positions, the Ge ions would act as acceptor ions. Germanium profiles on these ion implanted GaAs samples were then analyzed and determined by means of Secondary Ion Mass Spectrometry (SIMS). During this SIMS analyses, energetic argon ion plasma was bombarded into the implanted GaAs sample for obtaining either secondary germanium ions and clusters which were then detected using the SIMS ion detector. The count number of germanium ions and clusters detected and collected in the SIMS detectors at every time represented the germanium concentration at every corresponding depth inside the implanted GaAs samples. These SIMS accounts represent the count number of germanium ion as a function of depth measured from the surface of the implanted GaAs sample. During the implantation, germanium ion beam doses were varied to observe the effect of germanium ion beam on the germanium ion profiles on the GaAs samples. The SIMS results were also compared with RBS channeling analysis. The results indicated that SIMS and RBS spectra were directly proportional to the germanium ion beam doses. Keywords: Implantation, Intrinsic, Zinc blende, GaAs, Germanium Share Link | Plain Format | Corresponding Author (Imam Rofii)

332	PHYSICAL SCIENCES	ABS-121
Replica Trick Entanglement Entropy of f(R) Black Hole Spacetime Hadyan Luthfan Prihadi and Freddy Permana Zen and Seramika Ariwahjoedi Institut Teknologi Bandung Abstract Replica trick calculation of entanglement entropy is used to derive the entanglement entropy of maximally-extended black hole spacetimes in -f(R)- gravity. We use some static and spherically symmetric black hole solutions with charge and cosmological constant. We find that for some specific form of -f(R)-, some solutions does not reproduce the area-law Bekenstein-Hawking entropy, while some other solution still obey the area-law entropy. Keywords: Entanglement, Entropy, Black Hole, Modified Gravity Share Link | Plain Format | Corresponding Author (Hadyan Luthfan Prihadi)

333	PHYSICAL SCIENCES	ABS-125
Identification of the existence of subsurface pipes using the electrical resistivity method Mohamad Nasro (a), Umar Fauzi (a*), Enjang Jaenal Mustopa (a), Ihsan Imaduddin (b) a) Faculty of Mathematics and Natural Sciences (FMIPA), Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132, Indonesia *umarf[at]itb.ac.id b) Faculty of Science and Technology, Bandung University of Muhammadiyah Jalan Soekarno Hatta 752, Bandung 40614, Indonesia Abstract Subsurface investigation is an important start to obtain complete information about subsurface conditions. Often beneath the surface are objects such as pipes, cables, and other utilities. Before digging or drilling, it is very important to know their exact presence and depth. Many studies use geophysical methods to identify the presence of subsurface objects. This thesis uses the electrical resistivity method which is one of the geophysical methods to identify the presence of subsurface pipes. This electrical resistivity method analyzes the distribution of subsurface resistivity values from the electric potential values obtained when injecting direct current (DC) into the subsurface. The data acquisition technique of the electrical resistivity method is perpendicular (90 degrees) to the pipe axis, the measurement system uses 32 electrodes and the distance between the electrodes used is 1 meter. This study varies the types of Wenner Alpha, Wenner-Schlumberger, and Dipole-Dipole configurations. The purpose of this configuration variation is to be able to find out the ^best^ configuration when conducting a survey related to the identification of subsurface pipes. Forward modeling is done by placing the pipe anomaly at a depth of 1 meter below the surface to obtain synthetic data. After processing the data using least-square inversion, then analyzing and interpreting the data, from the 3 types of configurations used, the dipole-dipole configuration produces a better 2D model for identifying subsurface pipes compared to other configurations Keywords: Electrical resistivity method, Pipes, Forward modeling, Least square inversion Share Link | Plain Format | Corresponding Author (Mohamad Nasro)

334	PHYSICAL SCIENCES	ABS-152
NO Reduction Reaction on Cu catalyst Muhammad Rifqi Al Fauzan\(^{1,2}\), Thanh Ngoc Pham\(^1\), and Yoshitada Morikawa\(^1\) \(^1\) Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871, Japan \(^2\) Department of Electrical Engineering and Informatics, Vocational College, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia Abstract The dissociation of NO on Cu(100) is studied by using density functional theory (DFT). By exploring the minimum energy pathway, we found that the dimer-mediated dissociation is preferable compared to the direct monomer dissociation. An upright (NO)\(_2\) is initially formed and transformed into an upright ONNO then into a flat-lying ONNO. Subsequently, the flat-lying ONNO reacts to form N\(_2\)O and O with a low effective activation energy of 0.41 eV. This energy barrier is smaller compared to those Cu(111) and Cu(211) surfaces, which were reported as 0.84 eV and 0.62 eV, respectively. The formation of N\(_2\)O on the surface is followed by two possible pathways, namely, N\(_2\)O desorption with a 0.21 eV energy barrier and N\(_2\) desorption to yield adsorbed O atom with a small activation energy barrier. Our result suggests that the formation of dimer intermediate is the key to the high reactivity of NO on Cu(100) surface. We are interested in studying further regarding this reaction on the other Cu surfaces. Keywords: NO reduction, Cu-based catalyst, DFT Share Link | Plain Format | Corresponding Author (Muhammad Rifqi Al Fauzan)

335	PHYSICAL SCIENCES	ABS-166
Cosmological Consequences of Higher Dimensional Rastall Gravitational Theory Tegar Ari Widianto, Ahmad Khoirul Falah, and Bobby Eka Gunara Institut Teknologi Bandung Abstract Rastall theory was proposed to modify General Relativity on the assumption that conservation of the momentum energy tensor (EMT) no longer applies to curved spacetime. The scalar field model was originally proposed as an alternative to the cosmological constant problem which later became an alternative to the dynamical dark energy (quintessence) model. One specific form of the scalar field that has been proposed and appears naturally in various physical theories is the field with exponential potential. This research aims to study the cosmological consequences of this combination, the Rastall theory, and the scalar field, in higher dimensional spacetime using the dynamical system analysis method. The evolution of the universe is studied by determining which components dominate in each era of its evolution through the critical points of the autonomous equation. Then, we analyze how the stability properties of the critical points in question use the linear stability method to determine which model fits our universe physically. Furthermore, we apply our cosmological model to explain the inflationary era in the early universe and dark energy, the component that causes the universe to expand rapidly, today. Based on our interpretation, the inflation model is given by an unstable solution while the dark energy model is represented by a stable one. We also find that power-law inflation can still occur in the Rastall cosmological model. With the additional parameter-Rastall parameter, the slow-roll parameter -p- can be so huge such that it has the chance to solve the standard cosmological problems. Keywords: Please Juscosmology, rastall theory, scalar field, higher dimensional spacetime, inflation, dark energy, critical point, power-law inflationt Try to Submit This Sample Abstract Share Link | Plain Format | Corresponding Author (Tegar Ari Widianto Widianto)

336	PHYSICAL SCIENCES	ABS-177
Determination of Physio-Mechanical Equivalence Adrianus Inu Natalisanto, Rahmiati Munir, Rahmawati Munir, Ahmad Zarkasi, Niken Ari Safitri Program Studi Fisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Mulawarman Abstract The heat-mechanical equivalence, namely the ratio between heat and mechanical energy, has been known in the field of thermodynamics and was discovered experimentally by Joule in a physical system, namely 1 calorie is equivalent to 4.184 joules. In this research a similar thing has been carried out, but in the field of biophysics and in the system of human body, namely the determination of the physio-mechanical equivalence by measuring the value of the proportionality constant of physiological energy and biomechanical energy. Physiological energy relates to the energy expended by a person during his activities and is reflected in changes in his heart rate, while biomechanical energy relates to the person^s activity in terms of Newtonian mechanics. In this study, an equation has been derived that relates physiological energy and biomechanical energy in humans, then the physio-mechanical equivalence of the subject doing the bench press movement is calculated using the equation and measurement data on the subject. From this study, the physio-mechanical equivalence of the subject were obtained, namely 1 heart beat is equivalent to 8.591 joules. Keywords: equivalence, physiological energy, biomechanical energy Share Link | Plain Format | Corresponding Author (Adrianus Inu Natalisanto Natalisanto)

337	PHYSICAL SCIENCES	ABS-219
Determination of Soil-to-Plant and Plant-to-Cow^s Milk Transfer Factor for Natural Radionuclides and Radiocesium on Cattle Farm in Lembang Imam Ghazali Yasmint1, Abdul Waris1,2, Sidik Permana1,2, Eko Pudjadi3 & Ismail Humolungo2 1Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology Ganesha No. 10 Bandung, Indonesia, 40132 2Department of Nuclear Science and Engineering, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha No. 10 Bandung, Indonesia, 40132 3Environmental Laboratory, Subs-section of Environmental Safety, Radioecology Section, Center for Technology of Safety and Radiation Metrology, National Nuclear Energy Agency of Indonesia, Lebak Bulus Raya No.49 Jakarta, Indonesia, 12440 Abstract Apart from nuclear reactors, natural radiation sources contribute to the radiation received by humans. Natural sources that produce natural radioactivity in the environment come from primordial radionuclides (U and Th series) exposure, which usually found in the soil. The presence of radiocesium in the ground indicates the presence of waste products from nuclear reactor accidents and nuclear weapons tests. Radionuclides in the soil will be transferred to plants (grass, vegetables and etc.) that we know as soil-to-plant transfer. Regularly, cow and other animals eat grass as their main source of food and the presence of radionuclides in the grass implicitly affects human health by consuming meat and milk (plant-to-cow^s milk transfer). Therefore, testing of soil, grass and cow^s milk is needed so that it can be predicted how much natural radiation enters the human body and the behavior of radionuclides transfer. Lembang, a sub-district in West Java Province, Indonesia has become the center of education and research for agriculture and animal husbandry in West Java. In this study, several soil, grass and cow^s milk samples were taken from the cattle farm in Lembang. Then, the nuclear radiation was measured using an ORTEC gamma spectrometer with HPGe detector. Radionuclides observed in this study were 226Ra, 232Th, 40K and 137Cs. Average activity concentration in soil is below the world^s average. Soil-to-plant and plant-to-cow^s milk transfer factor obtained are in line with the results from other studies, which shown that 40K has the highest transfer factor compared to other radionuclides. 137Cs was not found in milk samples so that only its transfer behavior was known from soil to plant. Keywords: Activity Concentration, Gamma Spectroscopy, Natural Radionuclides, Plant-to-Cow^s Milk, Radiocesium, Soil-to-plant, Transfer Factor. Share Link | Plain Format | Corresponding Author (Imam Ghazali Yasmint)

338	PHYSICAL SCIENCES	ABS-235
Optimization of Electrospinning Process Parameters using Box-Behnken Design for Nylon-6 Nanofibers Fabrication Riris Sukowati1, Bertolomeus Haryanto Agung3, Yadi Mulyadi Rohman1, Maria Gabriela Sabandar1, Asti Sawitri1, Dhewa Edikresnha1, Dian Ahmad Hapidin1,a), and Khairurrijal Khairurrijal1, 2, b) 1Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia. 2Department of Physics, Faculty of Science, Institut Teknologi Sumatera, Jalan Terusan Ryacudu, Way Huwi, Lampung 35365, Indonesia 3Departement of Physics Education, Faculty of Teaching and Education, Nusa Nipa University, Jalan Kesehatan No 3, Maumere, Indonesia a) Corresponding author: hapidin[at]fi.itb.ac.id b) Corresponding author: krijal[at]itb.ac.id Abstract In this research, the Box-Behnken (BBD) experimental design was utilized to optimize the process parameters involved in the electrospinning technique to produce nylon-6 nanofibers. To optimize the fabrication of nylon-6 nanofibers, process parameters including solution concentration, working voltage, and flow rate were varied across three levels of values, with a total of 15 experiments conducted. The study employed a nylon-6 solution as the precursor, with three different concentrations of 14 wt%, 16 wt%, and 18 wt%. The working voltage was varied between 15.5 kV, 17.5 kV, and 19.5 kV, while the flow rate was adjusted to 0.5 ml/h, 0.75 ml/h, and 1 ml/h. The morphology of the nylon-6 nanofibers and their average diameter were respectively examined using an optical microscope and ImageJ software. The experimental results obtained using the Box-Behnken experimental design were analyzed statistically using analysis of variance (ANOVA). The optimization analysis revealed that the solution concentration was the most significant factor that affected the diameter of the nylon-6 nanofibers. Based on the optimization results, the minimum nanofiber diameter was achieved at a solution concentration of 14 wt%, a working voltage of 19.5 kV, and a flow rate of 1 ml/h. Keywords: Nylon-6 nanofiber, Box-Behnken, Electrospinning, Parameter optimization Share Link | Plain Format | Corresponding Author (Riris Sukowati)

339	PHYSICAL SCIENCES	ABS-239
Preliminary Evaluation on Environment Nuclear Radiation at Various Cities in Java Island Imam Ghazali Yasmint1, Ahmad Lathiiful Quluub1 and Sidik Permana1,a) 1Nuclear Physics Laboratory, Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha No. 10 Bandung, Indonesia, 40132 Abstract Most ionizing radiation sources that are present in the environment expose people to it. One of the biggest contributors to that exposure comes from natural radiation sources. Cosmic, terrestrial, and internal radiations are all sources of natural radiation. A few artificial radiations that result from nuclear reactor activity, medical facilities, and various businesses have also contributed. Indonesia^s Java Island is where the majority of people live. A critical piece of information that can be utilized to assess radiation levels and potential sources of contamination is the evaluation of the natural background of nuclear radiation. Then, as information for the general public regarding radiation doses, it can also build a map of natural nuclear radiation in Java Island. In this study, measurements were made at numerous sites on Java Island, where a lot of people go and carry out their daily activities. The examination is carried out utilizing the Geiger-Muller-based GMC-320 Plus detector. The outcome will be displayed as a mapping area, the radiation level in CPM, and the radiation dose rate, which is displayed as the average level of background radiation. Keywords: CPM, Dose Rate, GMC-320 Plus Survey Meter, Java Island, Natural Radiation, Radiation Map Share Link | Plain Format | Corresponding Author (Imam Ghazali Yasmint)

340	PHYSICAL SCIENCES	ABS-251
Development of Magnetic Permeability Measurement for Annealed and Non-Annealed Metal Fenudya Sanding Putri1, Satryo Agung Wibowo2, Bagus Endar B. Nurhandoko1,3 1,3 Physics Department of Institut Teknologi Bandung Jalan Ganesha 10, Bandung 40132, Indonesia contact person:bagusnur[at]bdg.centrin.net.id 2 Rock Fluid Imaging Lab Jalan Raya Sukasenang Raya VA, Bandung 40124 Abstract We need information on the magnetic permeability of the material. Several applications for permeability values are needed in producing industrial equipment, such as transformers, magnetic impermeable casing, and magnetic field antennas. However, the accuracy of a magnetic permeability measurement device depends on the range of magnetic permeability values of the material used. Several magnetic permeability test methods can be carried out using guided and unguided measurement systems. However, these methods require high complexity, precise and stable calibration, special geometry, and a limited range of permeability measurements. In this paper, we test a prototype of a more efficient and flexible magnetic permeability measurement system. This prototype test was carried out on annealed and non-annealed ferrous metals. The results show the stable measurement and that the annealed iron has a higher magnetic permeability value than the permeability of an unannealed iron. The prototype of the measurement method shows good sensitivity to the measurement of the magnetic permeability of a material. Keywords: magnetic permeability- measurement of permeability- annealed metal Share Link | Plain Format | Corresponding Author (Fenudya Sanding Putri)

341	PHYSICAL SCIENCES	ABS-254
An Acoustic Analysis on Pronunciation of the Sundanese Letters ee, e, and eu Juju Julaeha(1), Jasmine Khairina(1), Syifa Nailufar Rahman(1), Galih Restu Fardian Suwandi(2) (1) Master of Physics Teaching Study Program, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia (2) Nuclear Physics and Biophysics Research Group, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia Abstract The fundamental frequency (pitch or F0) is the lowest frequency in a sound signal while the formant frequency is basically the resonant frequency that occurs in the vocal track. Both are acoustic parameters that are very essential to identify sound signals. The pitch and formant are extracted from the subject which consisted of 16-17 years old Sundanese 20 males and 20 females. Praat software is operated to extract pitch and the first to fourth formant (F1-F4) on each sound signal of the letters ee, e, and eu. The results of the analysis showed that each vowel ee, e, and eu in males had a smaller pitch and formant than in females, with gradient differences ee, e and eu was 48.22, 157.49, and 136.27. Regarding the significant level Two Tailed T-Test statistic calculation, the majority of formant frequency comparisons of 2 vocals (ee and e, e and eu, ee and eu) are significantly distinguished. The study also showed that several vocals had an undistinguished formant frequency at F3. It can be concluded that the pronunciation of ee, e, and eu between males and females can be identified through the fundamental and formant frequency. Keywords: Fundamental Frequency, Formant Frequency, Sundanese, Vowel ee, e and eu , Speech Processing Share Link | Plain Format | Corresponding Author (Galih Restu Fardian Suwandi)

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