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91	Materials Physics	ABS-122
TiO2 photocatalytic degradation of methylene blue using simple dip coating Fisca Dian Utami, Neni Surtiyeni, Nadya Amalia, Euis Sustini and Mikrajuddin Abdullah Institut Teknologi Bandung Abstract The purpose of recent work is to evaluate the effects of TiO2 in degrading organic wastewater. Technical TiO2 of anatase crystalline phase was used. TiO2 photocatalyst showed a powerful result in destroying organic effluent. Dip coating was conducted to immobilize the TiO2 particles onto the plastic buffer followed by putting the additional polymer (alteco glue). As a result, 100 mL of 25 mg L-1 methylene blue (MB) used in the photocatalyst test was successfully degraded after 12 hours of irradiation. Variation of TiO2 concentration and additional polymer was carried out to study the performance of the catalyst. Keywords: Photocatalytic degradation, TiO2, Dip-Coating method Share Link | Plain Format | Corresponding Author (Fisca Dian Utami)

92	Materials Physics	ABS-124
Graphene Growth Effort at Low Temperature by Using Hot Wire-Very High Frequency-Plasma Enhanced Chemical Vapor Deposition A Momang Yusuf(a, b), Kurniati A. (a), Ajeng E. (a), Jasruddin D. Malago (b), Fatimah A. Noor (a), Toto Winata (a*) a) Physics of Electronics Materials Research Group, Bandung Institute of Technology Jl. Ganesa 10, Bandung 40132, Indonesia *toto[at]fi.itb.ac.id b) Physics Department, Mathematics and Natural Science Faculty, Universitas Negeri Makassar Jl. Mallengkeri, Makassar, Indonesia Abstract We have attempted to grow graphene by using plasma enhanced chemical vapor deposition (PECVD) combined with hot wire (HW). Plasma was generated by Radio Frequency (RF) at Very High Frequency of 70 MHz. Raman spectra of the samples show that graphitic structure had been formed as indicated by sharp G band, followed by sharp D band which indicate that the samples highly contain disorder structure. However, the indistinct of 2D band from Raman spectra suggest that the obtained samples were graphite film which is many layers graphene. This result suggest that growth parameters still need to be optimized further to obtain high quality graphene which contain less than ten layers. Keywords: graphene, hot-wire, PECVD, Raman Share Link | Plain Format | Corresponding Author (A Momang Yusuf)

93	Materials Physics	ABS-131
Integrated Array of Dye-Sensitized Solar Cells and Supercapacitor for Photo Superkapasitor Multifunctional Harvesting Device Markus Diantoro1,2*, Akhmad Al Ittikhad1, Ida Vaeruza Albadi^ah1, Eny Latifah1, Ahmad Taufiq1, and Worawat Meevasana3 1Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia. 2Centre of Advanced Materials for Renewable Energy, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia 3School of Physics, Suranaree University of Technology, 111 University Ave, Muang District, Nakhon Ratchsima, 30000 Thailand Abstract Photosupercapacitor (PSc) was an integration of photovoltaic as a device for harvesting light energy and supercapacitor as an energy storage device. Multifunctional harvesting device has increasing demand in the green energy industry sector. In this study, we demonstrate the integrated array of photovoltaic type dye-sensitized solar cell and carbon-based supercapacitor. The photosupercapacitor integration will be arranged in a different arrangement, called sandwich and parallel arrangement. DSSC photoanode was used TiO2 material that deposited using screen printing method on FTO substrate. Activated Carbon/Carbon Black/SBR as material composite of electrode was deposited on the aluminium foil substrate using dr. blade technique. XRD characterization has identified the pure anatase phase in the TiO2 photoanode. Mesoporous morphology of TiO2 was identified by SEM characterization. The Ti element of photoanode has identified by EDX of 64.23 wt%. The UV Vis spectroscopy curve has identified the absorbance of TiO2 photoanode in the wavelength range of 290 - 460 nm. The J-V characterization shows that TiO2 photoanode has power conversion efficiency of 0.85%. The I-V characterization of photosupercapacitor performance was arranged by sandwich and parallel. The photosupercapacitor was treated with light and dark under light illumination of 100 mW.cm-2. The performance of photosupercapacitor sandwich has shown higher the parallel arrangement. Keywords: Photosupercapacitor, dye-sensitised solar cells, supercapacitor, integration, TiO2 Share Link | Plain Format | Corresponding Author (Akhmad Al Ittikhad)

94	Materials Physics	ABS-132
Quasi-static analysis on the solar absorption performance of the semiconductor-metal core-shell nanoparticle Fitriyadi, Azrul Azwar and Fatimah A. Noor 1Physics of Electronics Material Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung, Indonesia 40132, Physics Department, Faculty of Mathematics and Natural Sciences, Tanjungpura University, Pontianak, Indonesia, 78115 Abstract In this study, we perform a quasi-static analysis of the light scattering theory to calculate the absorption performance of a core-shell nanoparticle under the solar illumination. This analysis is a good approximation for describing the classical interaction of light and nanoparticle of size much smaller than the incident wavelength. In this limits, the light scattering problem could be simplified by solving the electrostatic boundary condition of the Laplace equation. Specifically, we calculate for Ge and Si as the semiconductor core with the noble metal (Ag, Ag and Cu) as the metallic shell embedded in SiO2 medium. We found that the nanoparticle with the Ag shell exhibits the highest solar absorption performance both for the Si or Ge as the core material. Further, the solar absorption performance of Ge-Ag core-shell nanoparticle is slightly higher than the Si-Ag. Finally, we also found that the solar absorption performance of the semiconductor-metal core-shell nanoparticles increase as the core radius and the shell thickness increase. Keywords: solar absorption, core-shell nanoparticle, noble metal, quasi-static, Plasmon resonance Share Link | Plain Format | Corresponding Author (Azrul Azwar)

95	Materials Physics	ABS-136
Variation of Mesh Peel Ply and Gelcoat on Mechanical Properties of Carbon Twill-Vinyl Ester Composites Using Vacuum Assisted Resin Infusion Manufacturing Method Taufiq Satrio Nurtiasto1, Fajar Ari Wandono1, Nurul Lailatul Muzayadah1, and Rohmat Fazabik2 1. Aeronautics Technology Center LAPAN 2. Mechanical Engineering, Faculty of Engineering, Universitas Bengkulu Abstract This study discussed the mechanical properties of a modified carbon twill vinyl-ester composite using the Vacuum Assisted Resin Infusion (VARI) method. Modifications were made by adding the number of mesh peel ply and gelcoat. Mechanical properties testing was done to determine the average value of the tensile test and the average value of the shear test. The finite element simulation was also performed to compare the load versus displacement graph with the testing. The VARI composite with double mesh peel ply has an average tensile test value of 536.29 MPa. The VARI composite with the addition of gelcoat has an average tensile test value of 551.58 MPa. The tensile test results of the VARI with double mesh peel ply increased by 1.61%, while VARI with the addition of gelcoat increased 4.34% from the composite with the standard method of 527.62 MPa. The VARI composite with double mesh peel ply has an average shear test value of 20.90 MPa, while VARI composite with the addition of gelcoat has an average shear test value of 24.81 MPa. The tensile test results of the VARI with double mesh peel ply decreased 17.20%, while the VARI with the addition of gelcoat decreased 30.24% from the composite with the standard method of 29.97 MPa. Keywords: Vacuum-Assisted Resin Infusion, Gelcoat, Mesh Peel Ply, Twill Carbon, Vinyl-Ester, Finite Element Simulation. Share Link | Plain Format | Corresponding Author (Taufiq Satrio Nurtiasto)

96	Materials Physics	ABS-138
Fundamental Theory for Identifying Optical Properties of Metamaterials with Combination of Wiremesh Structure (WS) and Split Ring Resonator (SRR) Fina Fitratun Amaliyah (a*), Juliasih Partini (b) a) UIN Sultan Maulana Hasanuddin Banten, Jendral Sudirman 30 Serang, Banten 42118, Indonesia b) Universitas Gadjah Mada (UGM), Bulaksumur, Sleman, DI Yogyakarta 55281, Indonesia Abstract It has been studied theoretically about the phenomenon of electromagnetic wave propagation, including the reflection and refraction events that affect a material that has permittivity (&#949-) and permeability (&#956-), both of which are negative (metamaterial). The metamaterial being studied is a combination of material with negative permittivity (&#949-), namely Wiremesh Structure (WS) and material with negative permeability (&#956-), namely Split Ring Resonator (SRR). In this case negative permittivity (&#949-) and negative permeability (&#956-) are a function of the frequency (&#969-) which can be plotted on a graph to make it easier to get the negative interval of the two materials. The propagation of electromagnetic waves on metamaterials certainly has new consequences for Maxwell^s equations. In addition, reflection and refraction on metamaterials produce modifications to well-established physical laws, such as Snell^s law and Fresnel^s law. From these two laws, quantitative information is obtained regarding the reflection coefficient (r), transmission coefficient (t), reflectance (R), and transmittance (T). Keywords: Reflection, Transmission, Reflectance, Transmittance. Share Link | Plain Format | Corresponding Author (Fina Fitratun Amaliyah)

97	Materials Physics	ABS-143
Sound Absorption Characterisation of Layered Arrangements of Pineapple Leaf Fiber-Epoxy Composite prepared by a Simple Mixing - Hot Pressing Process Widayani1)*, Abiyoga Noeriman1), Triati Dewi Kencana Wungu1,2), Damar Rastri Adhika 2,3) 1) Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia 2) Research Centre for Nanoscience and Nanotechnology, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40132 Indonesia 3) Advanced Functional Material Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia Abstract As with other natural fiber-based composites, pineapple leaf fiber-epoxy composites could be potentially used as sound absorber materials. Sound absorption coefficient of a material depends on several factors, such as thickness and sound frequency. Layered arrangement is usually used to increase thickness. In this research, sound absorption characteristic of one-, two- and three- layer arrangement of the Pineapple leaf fiber-epoxy composite containing 11 and 17% (w/w) of epoxy concentration have been studied. The composites were prepared by a simple mixing followed by hot pressing process, and the sound absorption coefficient was measured according to ISO 10534-2 by using an impedance tube. At low frequency range (<1 kHz) the sound absorption coefficient increases as the layer number increases. At frequency range >1 kHz, the sound absorption coefficient variates at above 0.6. In this frequency range, the sound absorption coefficient of Pineapple Leaf fiber-epoxy composite is influenced by epoxy concentration. The composite containing 11% of epoxy concentration gives higher sound absorption coefficient compared to that of 17%. One-layer composite is better sound absorbing materials at frequency >3 kHz, as it gives higher sound absorption coefficient compared to other arrangements. Keywords: pineapple leaf fiber-epoxy composite, sound absorption coefficient, layered arrangements Share Link | Plain Format | Corresponding Author (Widayani Sutrisno)

98	Materials Physics	ABS-144
PHYSICAL PROPERTIES OF SIDIKALANG ROBUSTA COFFEE BEANS MEDIUM ROASTED FROM VARIOUS COLORS OF COFFEE CHERRIES Elin Yusibani(a*), Rizki Ilhamsyah Putra(a), Adi Rahwanto(a), M Syukri Surbakti(a), Rajibussalim(a), Rahmi(b) (a)Physics Department, FMIPA jln Teuku Nyak Arief Darussalam Universitas syiah kuala Indinesia 23111 (b)Chemistry Department, FMIPA jln Teuku Nyak Arief Darussalam Universitas syiah kuala Indinesia 23111 *e_yusibani[at]unsyiah.ac.id Abstract The purpose of the present study is to investigate the physical properties of medium roasted Sidikalang robusta coffee beans originated from various colors of coffee cherries. A semi-wet method has been applied for each coffee cherry with a range of fruit ripeness (green, yellow, orange, bright red and dark red). The physical properties measurements include mass loss, mass density, porosity, and water content. After roasted for medium level, the coffee density is difference for each coffee cherries colors namely 0.42 g/cm3 (green cherries), 0.31 g/cm3 (yellow cherries), 0.40 g/cm3 (orange cherries), 0.34 g/cm3 (bright red cherries), and 0.25 g/cm3 (dark red cherries). The mass declined after medium roasted is 16.82% (green cherries), 17.00% (yellow cherries), 18.70% (orange cherries), 18.32% (bright red cherries) and 16.76% (dark red cherries). The coffee beans porosity after medium roasted is decreases by 13.56% for green cherries and 16% for yellow cherries, and increased by 12.22 (orange cherries), 3.44% (bright red cherries), and 6.88% (dark red cherries). Finally, the water content of coffee beans was 8.38% (green cherries), 9% (yellow and orange cherries), 7.91% (bright red cherries), and 10.83% (dark red cherries). Keywords: Robusta, Sidikalang, Medium Roasted, Coffee been, coffee cherries Share Link | Plain Format | Corresponding Author (Elin Yusibani)

99	Materials Physics	ABS-145
A facile approach for preparing Zr-BDC and Zr-BDC-NH2 MOFs using solvothermal synthesis Lena Rahmidar, Ni Luh Wulan Septiani, Nugraha, Brian Yuliarto Department of Engineering Physics, Institut Teknologi Bandung Abstract In the last two decades, researchers have developed new compounds made of central metals that bond in coordination with organic ligands as linkers (for example, benzene-dicarboxylic acid or BDC). These compounds are called metal-organic frameworks (MOFs) which are also known as coordination polymer compounds. MOFs have large surface area and porosity so they can be used for various purposes, such as for adsorption and removal of hazardous materials of CO2 and Hg. Here, we proposed a facile solvothermal method for preparing two kinds of MOFs with Zr as a central metal, i.e. Zr-BDC and Zr-BDC-NH2. The synthesized MOFs were then characterized using x-ray diffraction (XRD), fourier transformed infrared spectroscopy (FTIR), brunauer-emmett-teller (BET), field emission scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that both MOFs have a crystalline structure with cubic form on the surface of MOFs. Results of the FTIR analysis show the peak at 3400 1/cm that is due to the stretching of O-H bonds of both MOFs. In the Zr-BDC-NH2, peak at 1378 1/cm represents the stretching of N-H bonds in the amino benzene-dicarboxylic or terephthalic acid linker. The surface areas of Zr-BDC and Zr-BDC-NH2 MOFs are 714 and 757 m2/g, respectively. In further study, we will utilize these MOFs as a sensor for HER2 protein, a biomarker of breast cancer. Keywords: MOFs, Zr-BDC, Solvothermal, XRD, TEM Share Link | Plain Format | Corresponding Author (Lena Rahmidar)

100	Materials Physics	ABS-150
Synthesis of Filter Media Materials From Egg Shells For Waste Water Treatment Plant (WWTP) Application Resti Ayu Ningrum (a), Doli Bonardo (a), Sontang Sihotang (a), Syahrul Humaidi (a*) (a) Department of Physics, FMIPA, Universitas Sumatera Utara, Jl. Bioteknologi I Kampus USU, Medan 20155, Indonesia *syahrul1[at]usu.ac.id Abstract Water is an indispensable requirement for humans, such as for bathing, washing and latrines. One of the requirements for suitable water for use is a neutral pH. Most people living in swampy areas have problems with reddish-brown peat water caused by the high content of dissolved organic matter, especially humic acid and its derivatives. The low pH is also caused by the low content of cations, the presence of organic substances in the form of acids and suspended particles. In peat water, organic substances can cause the water to taste sour, so alkaline substances are needed to neutralize the acid in peat water. It is known that chicken egg shells contain Calcium Carbonate (CaCO_{3}). The content of Calcium Carbonate in egg shells is around 95%. This calcium carbonate is alkaline which can raise the pH of peat water. Almost all broiler egg shells contain calcium carbonate. Based on the calcium carbonate content of broiler egg shells, if the egg shells are used for filter media, the treated water can produce alkaline water, therefore filter media from chicken egg shells can be used to improve the quality of acidic peat water. FTIR spectrum of egg shell samples with 800^{o}C calcination process. It can be seen that the three highest peaks are at wave numbers 3637 cm^{-1}, 1438 cm^{-1}, and 871 cm^{-1}, which indicate the hydroxide strain functional groups in Ca(OH)_{3}, Carbon monoxide and calcite groups, respectively. Several studies also reported that the hydroxyl and carbonation groups at similar wave numbers were 3643 cm^{-1}, 1445 cm^{-1} and 877 cm^{-1}, and at 712 cm^{-1}, 876 cm^{-1}, and 1425 cm^{-1} which correspond to C=C, CO, and CS vibrations. The FTIR results presence of these functional groups at wave numbers 709 cm^{-1}, 871 cm^{-1}, and 1438 cm^{-1}. Keywords: Egg shells, Waste water, Calcium carbonate, Functional groups Share Link | Plain Format | Corresponding Author (Resti Ayu Ningrum)

101	Materials Physics	ABS-165
A novel method to determine the glass transition temperature of polymers Nadya Amalia1, Elfi Yuliza2, Desyana O. Margaretta3, Fisca D. Utami4, Neni Surtiyeni4, Sparisoma Viridi4, and Mikrajuddin Abdullah4 1Indonesian Institute of Sciences 2University of Bengkulu 3Sayyid Ali Rahmatullah State Islamic University Tulungagung 4Bandung Institute of Technology Abstract We propose a novel method for estimating the glass transition temperature of polymers. By placing the cantilever structure of a polymer in a temperature controlled environment, we were able to derive the temperature dependence of elastic moduli using an alternative non-destructive and non-contact method from our previous report [AIP Advances, 8(11), 115201]. We identified a drastic drop of the elastic modulus at a certain temperature and assumed this temperature corresponds to the glass transition temperature. We further introduced an equation to describe the elastic moduli around that critical temperature and were able to estimate the glass transition temperature for all polymeric materials tested. Surprisingly, the estimated glass transition temperatures conform to data obtained by direct measurement using the DTA device. Since the elastic modulus changes abruptly around the glass transition temperature, the proposed method might be more accurate than measurements using a DTA device where the glass transition temperature corresponds to the location of a weak peak on the DTA curve. This is the first attempt for estimating the glass transition temperature of polymers based on the bending of the cantilever structure, and appears to be the simplest method. The method is very potential for developing new equipment for determining the glass transition temperature of polymeric materials. Keywords: glass transition, elastic modulus, polymers, differential thermal analysis, cantilever structure Share Link | Plain Format | Corresponding Author (Nadya Amalia)

102	Modelling and Computational Physics	ABS-5
Effect of Tetrabutyl Ammonium on Methylene Blue-Clay Adsorption System Mia Ledyastuti(a*), Ovi Puspitasari Sofyan(b), M. Ali Zulfikar(c) a)Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia Jalan Ganesa no. 10 Bandung *mia[at]chem.itb.ac.id b)Chemistry Undergraduate Program, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia Jalan Ganesa no. 10 Bandung c) Analytical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia Jalan Ganesa no. 10 Bandung Abstract Artificial dyes such as methylene blue are commonly detected in textile waste. Clay can be used as an adsorbent for methylene blue in the treatment of textile waste. The addition of surfactants into the system, is often done to increase the adsorption capacity of the clay. This study discusses the effect of tetrabutyl ammonium surfactant on the adsorption capacity of pyrophyllite and montmorillonite clays in the adsorption of methylene blue. The method used is molecular dynamics simulation. The simulation at 300 K 1 bar results, show that the addition of tetrabutyl ammonium surfactant causes a 12-40% decrease in the binding of methylene blue on the pyrophyllite and montmorillonite surfaces. Therefore, the addition of tetrabutyl ammonium surfactant gave unsatisfactory results for the methylene blue-pyrophyllite and methylene blue-montmorillonite systems. Keywords: molecular dynamics, adsorption, methylene blue, pyrophillite, montmorillonite Share Link | Plain Format | Corresponding Author (Mia Ledyastuti)

103	Modelling and Computational Physics	ABS-39
Geometry Effect of CaCl2.6H2O at Charging and Discharging Process as Latent TES Akhmad Yusuf, Shofi Dhiya Ulhaq, Surjamanto Wonorahardjo, Inge Magdalena Sutjahja Physics Department, FMIPA, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung 40132, Indonesia Building Technology Research Group, SAPPK, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung 40132, Indonesia Abstract Phase Change Materials (PCMs) as thermal energy storage can store a relatively large amount of latent heat at a relatively constant temperature during the solid to liquid (melting process), or vice versa. With many applications of PCM as temperature regulation such as for building application, heating or cooling devices for battery, electronic, food preservation, and medicine, the geometry effect is significant to optimize its performance because each type of application requires a specific kind of geometry. This paper reports the simulation study for the nucleation of an inorganic PCM of CaCl2.6H2O (melting temperature 29 C) by using Ansys fluent for various 2D and 3D geometric shapes. The 2D objects consist of circles, squares, and rectangular, while the 3D objects consist of sphere, cube and cylinder. The density, heat capacity, thermal conductivity, and viscosity as the input parameters were taken or extrapolated from previous experimental studies. The simulation study results consisting of time-dependent temperature for the liquid to solid phase transition and time-dependent liquid mass fraction can be used to optimize the geometry of CaCl2.6H2O as the medium of thermal energy storage (TES). Keywords: phase change material (PCMs), thermal energy storage (TES), phase change simulations, CaCl2.6H2O, Ansys, latent heat Share Link | Plain Format | Corresponding Author (akhmad yusuf)

104	Modelling and Computational Physics	ABS-56
Monte Carlo Simulation for Quantum Harmonic and Anharmonic Oscillator within Epistemically Restricted Phase Space Representation M. Jauhar Kholili, Siska A. Rifianti, Eny Latifah, Ahmad R. T. Nugraha Indonesian Institute of Sciences Abstract We perform Monte Carlo simulations within the epistemically-restricted phase-space formulation of quantum mechanics for harmonic and anharmonic oscillators using a global random variable on the order of Planck^s constant. The calculation speeds in these simulations for finding the energy expectation values of the harmonic and anharmonic oscillators are comparable to the standard variational Monte Carlo simulation. We also numerically prove that the distribution function of the global random variable does not significantly affect the energy accuracy and speedup. This work paves the way toward the development of an alternative model of more efficient Monte Carlo simulations of various quantum systems. Keywords: Monte Carlo simulation, Phase-space formulation, Quantum oscillators Share Link | Plain Format | Corresponding Author (M Jauhar Kholili)

105	Modelling and Computational Physics	ABS-67
Qualitative Modelling the Dancing Volvox with Two-Body System: Comparing Simple Mechanics with Observation Video Sevi Nurafni (a*), Septian Ulan Dini (a), Intan Taufik (b), Sparisoma Viridi (a) a) Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *sevinurafni54[at]gmail.com b) School of Life Science and Technology, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Volvox cells normally construct a spherical colony of hundred of cells and moving together to perform their basic needs. More than moving a single colony, two attached Volvox colonies can dance and move together. This system can be modeled as a two-body system, where its center of mass (COM) is performing simple translation(TRAN) motion, while the two colonies center is rotating around the COM with roll (ROLL) or spin (SPIN) motions. From the available observation video, about 10 s or 300 frames can be isolated to get a clear picture of the dancing motion of two Volvox colonies. It has been observed that the dancing Volvox has a superposition motion of the other motion (TRAN, ROLL, SPIN), which has been compared qualitatively with the simple mechanics model of the two-body system. From the model, the translation velocity is about 1.25, and its roll and spin angular velocity are about 0.785 and 3.063, respectively. Keywords: dancing volvox, mechanics, two-body system, qualitative model Share Link | Plain Format | Corresponding Author (Sevi Nurafni)

106	Modelling and Computational Physics	ABS-98
Modelling of Motion of a Volvox Colony using Many-Body System and Its Qualitative Comparison with Observation Septian Ulan Dini(a*), Sevi Nurafni(b), Achmad Zacky Fairuza(c), Intan Taufik(d), Sparisoma Viridi(a), (b) (a)Master Program in Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia *septianulandini[at]gmail.com (b)Master Program in Computational Science, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Indonesia (c)Master Program in Nanotechnology, Graduate School, Institut Teknologi Bandung, Bandung 40132, Indonesia (d)School of Life Science and Technology, Institut Teknologi Bandung 40132, Indonesia Abstract Approximately 500-60,000 volvox cells constructed a colony with a spherical or elliptical hollow form. Each cell can use its flagella to move. In order for a colony of hundred cells to perform a direct motion, there must be a coordination of the flagella. In this work, we assume that the cells already form the spherical colony and can perform some simple motion types, i.e., translational (TRAN), roll (ROLL), spin (SPIN), and superposition of the motions, and neglect detail of each flagellum. It is possible to map each cell in the colony using angular positions with a constant radius R and different \(\theta_i\) and \(\phi_i\), where i = 1, 2, ..., N with N is the number of cells constructing a colony. The canter of the colony is \(r = (x, y, z)\). The TRAN mode can be obtained, where \(x(t) = x(0)+ v_x t\), \(y(t) = y(0)+ v_y t\), \(z(t) = z(0) + v_z t\), ROLL mode with \(\theta(t) = \omega(0) + \omega_\theta t\), and SPIN with \(\phi(t) = \phi(0) + \omega_\phi t\). Through the available observation video,\(v_x\), \(v_y\), \(v_z\), \(\omega_\theta\), and \(\omega_\phi\), are also shown to have a qualitative agreement. Keywords: Volvox colony, mechanics, many-body system, qualitative model. Share Link | Plain Format | Corresponding Author (Septian Ulan Dini)

107	Modelling and Computational Physics	ABS-115
Simulations of Stem Cell Spreading on Nanopatterned Ligands Using Simple Grid-Based Model Combined with Two-Dimensional Monte Carlo Method Achmad Zacky Fairuza (a*), Sparisoma Viridi (b,c), Suprijadi (b,c) a) Master Program on Nanotechnology, Graduate School, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *fairuza.zacky1[at]gmail.com b) Physics Study Program, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia c) Research Center of Nanoscience and Nanotechnology, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia Abstract Stem cell differentiation can be affected by nanopatterned ligands on the substrate to which the cells attach. This is predicted to occur due to the phenomenon of focal adhesion, where on the cell surface there are integrins that act as receptors and bind to ligands on the substrate. This process then affects the mechanical signals that determine the fate of the cell. One of the differences in cell differentiation is characterized by cell spreading. For this reason, here we create a simple grid-based model combined with two-dimensional Monte Carlo method to simulate the cell spreading phenomenon in nanopatterned ligands. In this model, we use square grid with the size of 15 nm per grid and approximately 3000 receptors in a single cell. The grids can be occupied by integrin receptors, ligands, or the bounded receptor-ligand. Integrin receptors will be able to move in a limited manner and interact with immobilized nanopatterned ligands. Reported experiment has shown that the difference in the distribution pattern and the distance between the ligands on the substrate affect the direction of stem cell differentiation. Therefore, the parameters tested in this model are the distance between the ligands in the range of 70 nm to 150 nm, the distribution pattern of the ligands, and the flexibility of the receptor movement. We hope that our model could show the differences in the shape and size of the cell spreading at different parameter configurations. This result will also be compared to reported observational result for further analysis. Keywords: Cell Differentiation- Cell Spreading- Nanopattern- Simulation- Stem Cell Share Link | Plain Format | Corresponding Author (Achmad Zacky Fairuza)

108	Modelling and Computational Physics	ABS-125
Experimental investigation of pile characteristics of non-spherical particles mixtures: pile height and angle of repose Putri Mustika Widartiningsih, Muhammad Iqbal Rahmadhan Putra, Dimas Praja, Aufa Rudiawan, Sparisoma Viridi(*) Granular Physics and Fluids Laboratory Nuclear Physics and Biophysics Research Division Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10, Bandung 40132, Indonesia *dudung[at]gmail.com Abstract Angle of repose is defined as the steepest angle of a conical pile that is naturally formed when a bulk of particulate solid poured onto a flat surface. It has been considered as one of important properties in characterizing granular material due to its effectiveness in determining flowability of granular, pile profile in an opaque container, and granular transportation system. Since the angle of repose is sensitive to the shape of individual particles, investigations through experiments and simulations for various forms of particles have been carried out. However, most of them were performed under homogeneous particle system. While in practical situation, granular mixtures consisting of a variety of particle shapes are commonly employed. This study presents an experimental investigation of angles of repose resulting from a mixture of two types of non-spherical particles. Experiments have been carried out with different compositions and have been repeated five times to ensure their reproducibility. The results show that the angle of repose linearly corresponds to the granular composition, where the coefficient of determination is ~0.93. Consequently, this study has proved the relationship between granular composition and characteristic of bulk granular. Keywords: angle of repose, granular mixture, granular pile, non-spherical particles Share Link | Plain Format | Corresponding Author (Putri Mustika Widartiningsih)

109	Modelling and Computational Physics	ABS-141
The role of initial horizontal position of intruder on Brazil Nut Effect phenomenon Muhammad Iqbal Rahmadhan Putra (*), Putri Mustika Widartiningsih, Dimas Praja Purwa Aji, Aufa Rudiawan, Sparisoma Viridi Granular Physics and Fluids Laboratory Nuclear Physics and Biophysics Research Division Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10, Bandung 40132, Indonesia *miqbalrp[at]gmail.com Abstract Brazil Nut Effect (BNE) is known as behavior when a large particle named intruder immersed in a group of smaller particles rises due to vertical vibration. Since this phenomenon has been adopted to investigate granular segregation in industries and also in particular fields like the size sorting of particles in asteroids, a complete understanding of the various parameters that affect this phenomenon is important to know. Past studies have shown that the physical properties of particles and properties of vibration play a major role in the BNE. Technically, the initial configuration of intruder and bed particles can affect the circulation of particles under vibration. However, studies on the initial position of an intruder are still lacking. In this study, we investigate how the evolution of the intruder in the segregation process by varying the initial position of the intruder horizontally which represents the initial configuration of the system as a whole. In order to be able to replicate the initial conditions for various grain and vibration parameters, we used 2-d frictionless simulations based on molecular dynamics. The three initial horizontal positions of the intruder used are (a) the middle, (b) between the middle and the edge, and (b) the edge of the container. While the variation to the frequency produces normalize acceleration \(\Gamma\) : 0.217, 0.870, 1.957, and 3.480. The result shows that the largest percentage of intruders that reach the top of the system in the final condition is the initial condition (b) with 13% followed by the initial condition (a) with 10%, while the initial condition (c) is significantly different resulting in a small percentage of 2%. The same result was observed in the three initial conditions in which no intruder was found that could rise to the top of the system with \(\Gamma\) = 0.217. In conclusion, it can be explained the role of the initial conditions of the system also still depends on the properties of vibration. Keywords: Granular, Molecular Dynamics, Simulation, Brazil Nut Effect Share Link | Plain Format | Corresponding Author (Muhammad Iqbal Rahmadhan Putra)

110	Modelling and Computational Physics	ABS-146
ABSORBER GEOMETRY SIZE OPTIMIZATION FOR ACOUSTIC ANECHOIC CHAMBER DESIGN USING GENETIC ALGORITHM Joel Christian (a*), Suprayogi (b), Nurwulan Fitriyanti (b) a) Engineering Pyhsics, School of Electrical Engineering, Telkom University Jl. Telekomunikasi No. 1, Terusan Buahbatu - Bojongsoang, Sukapura, Kec. Dayeuhkolot, Bandung, Jawa Barat 40257 * b) Engineering Pyhsics, School of Electrical Engineering, Telkom University Jalan Ganesha 10, Bandung 40132, Indonesia Jl. Telekomunikasi No. 1, Terusan Buahbatu - Bojongsoang, Sukapura, Kec. Dayeuhkolot, Bandung, Jawa Barat 40257 Abstract Anechoic chamber is a room that is made to resemble the condition of empty space. This room has an absorption rate of 99%. Absorber is an important part while manufacturing an anechoic chamber. In an anechoic chamber, absorber affects in terms of absorption and frequency range. Specification of the absorber used depends on the specification of the anechoic chamber to be made. The optimum absorber geometry size is required to maximize net volume of the anechoic chamber. Maximum measurable object size is 0.05x net volume of anechoic chamber. To overcome the problems, it is necessary to optimize the size of the absorber geometry. The size optimization of the absorber geometry has been carried out using a genetic algorithm with MATLAB as the programming software. Incidence angle of the wave and the width of the absorber are used as input parameters for absorber optimization. Optimization results in optimum peak angle and absorber length. The width of the absorber used in this optimization is 0.2 m. The peak angle obtained is 12.2 degree with a length of 0.936 m. The average absorption coefficient obtained is 0.886041. Keywords: Absorber, Anechoic chamber, Genetic Algorithm, Optimization. Share Link | Plain Format | Corresponding Author (Joel Christian)

111	Modelling and Computational Physics	ABS-148
A New Approach for Transfer Function in Inhomogeneous Universe: Linear-Time Varying (LTV) System Fargiza A. M. Mulki, Hesti R. T. Wulandari, M. Rafif Rabbani Astronomy Research Group, FMIPA, ITB- Bosscha Observatory, FMIPA, ITB Abstract A transfer function is a mathematical function that provides a lot of physical information about the state of a system. Matter transfer function describes the change of density contrast of mass over time so that it becomes the density contrast observed today. The square of the matter transfer function is proportional to its power spectrum which denotes the number of formed structures at each scale or size, which is certainly plausible to be observed. Most of the transfer function used today is extracted empirically from the known structures distribution, meanwhile the formal formulation is still very limited in terms of quantity. In this work, a matter transfer function will be built based on the linear-time varying (LTV) system approach, which is a continuation of the previous work, namely the development of the transfer function through a control theory approach for the linear-time invariant (LTI) system. Mathematically, a transfer function is a ^field^ whose properties are clear and definite. The mathematical properties possessed will be elaborated to obtain profound understanding of the transfer function. By employing the block diagrams used in engineering physics, the physical properties of the perturbations of the universe will be investigated through the analogy of a control machine. The formulation of the transfer function through the LTV system approach gives very good results with advantages in terms of processes and mechanisms through the block diagrams- therefore, it provides better understanding about the formation of the structure in the universe. The modular or ^plug and play^ property of this formalism makes it easier to be controlled, verified, and modified. Keywords: matter power spectrum, transfer function, inhomogeneous universe, control theory, cosmology Share Link | Plain Format | Corresponding Author (Fargiza A. M. Mulki)

112	Modelling and Computational Physics	ABS-158
Simple Qualitative Modeling of Particle Size Analysis using Ray Tracing Method Dellia Yulita(a), Muhammad Iqbal Rahmadhan Putra(a), Septian Ulan Dini(a), Erlina(a), Jessica (b, c), Arfat Pradana(c), Murni Handayani(d), Isa Anshori(b*, c), Sparisoma Viridi (a*,c). a) Granular Physics and Fluids Laboratory, Nuclear Physics and Biophysics Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *dudung[at]fi.itb.ac.id b) Lab-on-Chip Group, Biomedical Engineering Department, School of Electrical Engineering and Informatics, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia * isaa[at]staff.stei.itb.ac.id c) Research Center for Nanosciences and Nanotechnology (RCNN), Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia d) Research Center for Metallurgy and Materials, Indonesian Institute of Sciences, Banten, 15314, Indonesia Abstract Understanding particle size analysis is essential for pharmaceutical, mining, environmental, coatings, and other industries. Although there are numerous technologies that can be utilized to take particle size measurements, the results of those measurements are presented automatically and are sometimes difficult to understand. In this study, using the ray-tracing method, simple qualitative modeling of particle size analyzers can be developed. The laser is positioned as the initial position of the light source in x and y directions. The cell is pictured by cuvettes with four surfaces clear, and the particle is modeled as a sphere. Reflection of a single ray of the laser beam on many spheres can be performed using single ray reflection on a single sphere consecutively until the beam leaving the observation region or arriving at a light sensor. Then with vector formulation of ray direction after reflection on many spheres system \(\hat{n}_r \) we can define \(\hat{n}_{r,n} = \hat{n}_{i,n-1} - 2(\hat{n}_{i,n-1}. \hat{n}_{p,n})\hat{n}_{p.n}\) with n = 1, 2, 3, ... where \(\hat{n}_{r,0} = \hat{n}_i\). As a test of the particle size analysis model, the results are compared with measurements of the monodisperse polystyrene latex. Interesting patterns in FFT and autocorrelation function results are found. Unfortunately, this finding is still considered inconclusive, due to the pattern obtained is not completely similar to the experimental results. Keywords: Particle size analysis, ray tracing, qualitative model. Share Link | Plain Format | Corresponding Author (Dellia Yulita)

113	Modelling and Computational Physics	ABS-166
Stock Price Dynamics of The Jakarta Composite Index Modelled by PSO-Assisted Anharmonic Quantum Oscillator Tony Sumaryada (a*), Anisah Rahajeng Kartika Sari (a), Agus Kartono (a) (a) Department of Physics, IPB University, Kampus IPB Dramaga Bogor, Indonesia 16680 *tsumaryada[at]apps.ipb.ac.id Abstract In this paper we have modelled the stock price dynamics of the Jakarta Composite Index (JCI) by using an anharmonic quantum oscillator and the PSO (Particle Swarm Optimization) Algorithm. Some of the constants that affect the probability density of return are the ability of the market makers to control the market (&#947-), the behavior of contrarians and the trend followers to the price return (c), and the investor behavior towards perceived volatility (k). The simulation results have produced the smallest error of the Jakarta Composite Index at 8.36% for the opportunity density and 3.6% for the stock price returns. The probability density of the stock price return of JCI using the exponential smoothing method resulted in 17.77% error for opportunity density and 10.6% error on stock price return. Keywords: Quantum anharmonic oscillator, stock price, econophysics, PSO Algorithm Share Link | Plain Format | Corresponding Author (Tony Sumaryada)

114	Nanomaterial and Nanotechnology	ABS-11
Sensing Performance of Reduced Graphene Oxide with Various Degrees of Reduction Biaunik Niski Kumila (1), Chuan Pu Liu (2) (1) Department of Physics Faculty of Science and Technology, UIN Syarif Hidayatullah, Jakarta, Indonesia (2) Departement of Materials Science and Engineering, Faculty of Engineering, National Cheng Kung University, Tainan, Taiwan Abstract The electrical properties of reduced graphene oxide (rGO) have been practically shown to be very sensitive to surface adsorbates, thus making rGO very promising material to gas sensing application. However, a few study of rGO sensing sites leave a problem in advanced understanding the sensing mechanism method of rGO to any adsorbate. This work aims to study the effect of rGO reduction degree in the sensing sites growth as the affecting factor of methanol sensing performance. Oxygen containing functional groups was partially removed after thermal reduction along with the restoration of sp2-carbon bond rendering the recovery of its conductivity. However the structural defects were introduced after severe thermal reduction at 8500C. The suffucient amount of sp2 fraction and perfect combination of sensing sites, i.e - sp2 fraction, oxygen functional group and structural defects is shown to be important factor to achieve the highly sensitive sensor device with fast response and recovery time due to its unique response to various adorbates. In our work, higher device sensitivity towards methanol detection was discovered in comparison to previous work discovered by Lipatov et al 1 and we further proposed its possible sensing mechanism. Keywords: reduced graphene oxide- reduction degree- sp2 fraction- oxygen functional group- structural defect Share Link | Plain Format | Corresponding Author (Biaunik Niski Kumila)

115	Nanomaterial and Nanotechnology	ABS-13
Study on optical properties of Carbon nanodots by annealing mediated rice powder as a carbon source Maria jaya, Albert Zicko Yohanes, Redi K. Pingak, Zakarias Seba Ngara University of Nusa Cendana Abstract Abstract is submitted as file Keywords: optical properties, Carbon nanodots, rice powder, annealing, carbon source Share Link | Plain Format | Corresponding Author (Zakarias Seba Ngara)

116	Nanomaterial and Nanotechnology	ABS-15
Band gap analysis of CNTs made with varied CH4 flow rates using the HWC-in plasma-VHF-PECVD method for solar cell applications K Abidin, A. C. Keintjem, J D Malago, F A Noor, T Winata Physics of Electronic Materials Research Division, Department of Physics, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Bandung, Indonesia. Abstract This study focused on analyzing the energy gap of carbon nanotubes (CNTs) using SEM and UV-VIS characterization. CNTs were grown using the HWC-in plasma-VHF-PECVD method with varied of CH4 flow rates. The substrate of CNT growth was a glass slide prepared with an Ag catalyst. The Ag catalyst was deposited using thermal vacuum evaporation. Based on the SEM characterization, the CNT growtn with a CH4 flow rate of 30 sccm had the smallest energy gap. However, the UV-VIS spectral data showed that the CNT formed with a CH4 flow rate of 30 sccm had the largest band gap. In the UV-VIS analysis, the energy gap decreased with increasing CH4 flow rate. The CNTs formed using this HWC-in plasma-PECVD method were semiconductor CNTs that grew with base growth mode Keywords: CNT, Bandgap, HWC in plasma VHF PECVD Share Link | Plain Format | Corresponding Author (Kurniati Abidin)

117	Nanomaterial and Nanotechnology	ABS-28
Fast-Forward Method of Adiabatic Dynamics for a Spin-1/2 Particle Single Qubit System Ryan Sugihakim (a*), Iwan Setiawan (b), Bobby Eka Gunara (a) a) Theoretical and High Energy Physics, Department of Physics, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *ryan.s.hakim[at]gmail.com b) Physics Education Department, University of Bengkulu, Kandang Limun, Bengkulu 38371, Indonesia Abstract Controlling adiabatic quantum dynamics, i.e. using slowly-changing parameters to keep the energy level of the state of the system unchanged, is useful to obtain a geometric phase known as Berry phase. This geometric phase can be used to design a quantum logic gate in quantum computation. Motivated by this, we present a technique to achieve the Berry phase and its acceleration of the adiabatic dynamics based on the fast-forward technique developed by Masuda-Nakamura. The method is applied to a single qubit system of a spin-1/2 particle interacting with external magnetic field. The result of this paper is a transformation of the Hamiltonian from the adiabatic dynamics to its accelerated version of such dynamics. Keywords: shortcuts to adiabaticity- fast-forward method- qubit- geometric quantum computation Share Link | Plain Format | Corresponding Author (Ryan Sugihakim)

118	Nanomaterial and Nanotechnology	ABS-34
Fabrication of Polyvinylpyrrolidone (PVP) Nanofibrous Membranes using Mushroom-Spinneret Needleless Electrospinning Efa Latiffah (a), Bertolomeus Haryanto Agung (a), Dian Ahmad Hapidin (a), Khairurrijal Khairurrijal (ab*) a) Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia b) University Center of Excellence - Nutraceutical, Bioscience and Biotechnology Research Center, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia *krijal[at]fi.itb.ac.id Abstract Mushroom-spinneret is an improved spinneret design for needleless electrospinning apparatus, which has a bowl-shaped base with a mushroom-shaped cover. The mushroom spinneret can overcome some limitations that is often associated with the needleless electrospinning technique, i.e., high excitation voltages, poor stability of free liquid, and difficulty of controlling the spatial motion of multiple jets. In this study, we fabricate polyvinylpyrrolidone (PVP) nanofibrous membranes using mushroom-spinneret needleless electrospinning and determine the effect of solution concentration and applied voltage on the fiber morphology and diameter. The solution concentration had significant effect on the fibers diameter. When the solution concentration was increased from 8 wt% to 12 wt%, the average fibers diameter increased from 995.87 nm to 1310.71 nm and the fibers diameter distribution became wider. Moreover, the average fiber diameter decreased from 1311.60 nm to 1161.33 nm when the applied voltage was increased from 30 kV to 45 kV. The coefficient of variations (CV) for all membrane samples ranged from 0.12 - 0.26, indicated uniform fibers. Keywords: Needleless Electrospinning, Mushroom Spinneret, Nanofiber Share Link | Plain Format | Corresponding Author (Efa Latiffah)

119	Nanomaterial and Nanotechnology	ABS-36
Constructing fast forward adiabatic spin dynamics from semiclassical approach Iwan Setiawan, Ryan Sugihakim, Bobby Eka Gunara University of Bengkulu, Bandung Institute of Technology Abstract Fast forward adiabatic dynamics is designed to accelerate the evolution of wave function the n^th eigenstate of an initial Hamiltonian H(0) to the n^th eigenstate of a final Hamiltonian H(&#964-), in finite time. This scheme is constructed by using two opposite parameters i.e adiabatic paramater with a very slow dynamics to keep the adiabaticity and time scaling factor to accelerate the system. Fast forward adiabatic dynamics is constructed by obtaining the fast forward potential VFF that can steer the wave function to move in a shorter time. The procedure for constructing VFF generically leads to divergent behavior, as a result this method has been restricted to ground-state wavefunctions. Here we will constructed the fast forward potential by considering a semiclassical approach an applying to spin model. In this semiclassical spin model, fast forward Hamiltonian will accelerate the dynamics of the spin adiabatically Keywords: Fast forward, adiabatic, spin, semiclassical Share Link | Plain Format | Corresponding Author (Iwan Setiawan)

120	Nanomaterial and Nanotechnology	ABS-42
Study of Lysine and Asparagine as Capping Agent for Gold Nanoparticles Annisa Tsalsabila (a,b), Yuliati Herbani (a*), Yessie Widya Sari (b) a) Research Center for Physics, Indonesian Institute of Sciences, Kawasan Puspiptek Gedung 442, Tangerang Selatan, Banten,15314, Indonesia *yuliati.herbani[at]lipi.go.id b) Department of Physics, Faculty of Mathematics and Natural Sciences, IPB University, Jl. Meranti Wing S, Bogor, Jawa Barat, 16680, Indonesia Abstract The wide application of gold nanoparticles has attracted much attention to the development of research in gold nanoparticles. In this study, the gold nanoparticles were prepared by chemical reduction method using potassium tetrachloroaurate as the gold source and sodium borohydride as reducer agent. The formation of gold nanoparticles was confirmed by surface plasmon spectra in ultraviolet-visible spectroscopy at wavelength 507 nm. The capping process of gold nanoparticles was studied using two different charges of amino acids. The asparagine had used as uncharge amino acid and lysine as a positive charge amino acid. The redshift in surface plasmon spectra showed the aggregation of the gold nanoparticles after being capped with amino acids that indicates the surface modification. The zeta potential results indicate the lysine capped gold nanoparticles have slightly higher stability than the asparagine capped gold nanoparticles. These stability and surface modification of gold nanoparticles are expected to increase their utilization on biological and medical applications. Keywords: aggregation- asparagine- gold nanoparticles- lysine- stability Share Link | Plain Format | Corresponding Author (Annisa Tsalsabila)

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