nan Suprijadi

The study of electronic structure and properties of silicene for gas sensor application

In this study, we investigated the adsorption of gas molecules (H2S, CO) on pristine silicene using first principles calculation. The structure, electronic properties, and adsorption energy of H2S,CO/silicene are discussed thoroughly. We found that the pristine silicenewith low buckling structure is the most stable as compared with planar and high buckling structures. Silicene was able to detect a gas molecule which can be observed according tothe density of states analysis. Though a gas molecule adsorbed weakly, the electronic properties of the low buckling pristine silicene changed from semi-metal (zero band gap) to semiconductor. The adsorption energy of H2S and CO on silicene is 0.075 eV and 0.06 eV, respectively.

Enhanced 1057 nm luminescence peak and radiative properties of laser pump Nd3+-doped sodium borate glasses

This paper presents a study on the spectroscopic and radiative properties of Nd³⁺ ions in sodium-borate glasses (B₂O₃-Na₂O-PbO-ZnO-Li₂O). The thermal behaviors of the sample glasses were observed using thermogravimetric analysis (DTA) and a -12% total mass changes was recorded during a thermal treatment from 75°C to 900°C. The Judd-Ofelt parameters (Ω_2,4,6) have been computed from the experimental and theoretical oscillator strengths, as well as from the optical absorption spectra. Several important radiative properties such as radiative transition probability (A_R), branching ratio (β_R), emission cross section (σ_e) and fluorescence lifetime (τ) of the ⁴F_3/2 → ⁴I_11/2 transition have been obtained and compared with other glasses from previous studies. The calculations of emission cross section and quantum efficiency have shown that the 1.0 mol.% Nd³⁺-doped glass makes a good potential laser candidate at the ⁴F_3/2 → ⁴I_11/2 transition.

Study on transport properties of silicene monolayer under external field using NEGF method

We investigate the current-voltage (I-V) characteristics of a pristine monolayer silicene using non-equilibrium Green function (NEGF) method combining with density functional theory (DFT). This method succeeded in showing the relationship of I and V on silicene corresponding to the electronic characteristics such as density of states. The external field perpendicular to the silicene monolayer affects in increasing of the current. Under 0.2 eV external field, the current reaches the maximum peak at Vb = 0.3 eV with the increase is about 60% from what it is in zero external field.

Application of computational physics: Blood vessel constrictions and medical infuses

Application of computation in many fields are growing fast in last two decades. Increasing on computation performance helps researchers to understand natural phenomena in many fields of science and technology including in life sciences. Computational fluid dynamic is one of numerical methods which is very popular used to describe those phenomena. In this paper we propose moving particle semi-implicit (MPS) and molecular dynamics (MD) to describe different phenomena in blood vessel. The effect of increasing the blood pressure on vessel wall will be calculate using MD methods, while the two fluid blending dynamics will be discussed using MPS. Result from the first phenomenon shows that around 80% of constriction on blood vessel make blood vessel increase and will start to leak on vessel wall, while from the second phenomenon the result shows the visualization of two fluids mixture (drugs and blood) influenced by ratio of drugs debit to blood debit.

A comprehensive characterization of a linear deformation sensor for applications in triaxial compression tests

A linear deformation transducer (LDT), which will be applied to triaxial tests for determining deformation behavior of soils, was designed. It, which is made from a thin and flexible steel strip and a strain gage (KFG-5-120-C1-16L1M2R) bonded on the strip using an adhesive, was characterized systematically. Soil deformation was simulated by applying a certain force to the steel strip. The deformed steel strip was converted into a resistance by the strain gage. A full Wheatstone bridge was used to change the resistance into a small analog voltage. The small analog voltage was then amplified by an instrumentation amplifier. This analog voltage was finally processed by a digital data acquisition system consisting of a 12-bit analog to digital converter (ADC) and a microcontroller. It was found that the Wheatstone bridge output voltage obtained by applying a positive change in deformation (the present deformation is bigger than the previous one) is the same as that achieved by its negative change. When an input voltage was supplied to the bridge, the strain gage resistance reduces slightly with the maximum reduction about 1 ohm, from its static resistance of 119.6±0.4 ohm, depending on the force applied to the steel strip and the input voltage supplied to the bridge. For achieving the maximum deformation of 15 mm, the instrumentation amplifier used the supply voltage of 12 V and the gain resistor of 240±1% to get an amplification or gain of 204.8.

Color Image processing for measuring length deformation in compression test

An image processing method was used to measure sample deformation during a compression test. The images were first calibrated from pixels to millimeters using a ruler which was included in the scene. Analyzing is done by discriminating objects by their colors. The results showed a good agreement with the actual values measured by a compression test instrument with errors up to 0.058 cm.

Stability and electronic properties of defective single walled carbon nanotubes (CNTs)

In this project we using density functional theory (DFT) to investigate stability and the changes of electronic properties of single walled carbon nanotubes (SWCNT) defect by vacancy. We chosen a (10,0) and (8,0) SWCNT pristine geometry which have zigzag structure. We observed that defect not only can affect the changes of properties such as energy, bond length, and deformation of CNT structures, but also the stability and the electronic properties of CNT. The changes of various bond length of atoms around the vacancies area about 0.051 A0smaller or 0.1 A0 larger than the original C-C bond length. In addition, by calculating the formation energy, it gives us information that divacancy or V2 is the most stable vacancy. Numbers of vacancy make an electronic properties transition from semiconductor to metal.

First Principle Calculation : Investigation on interaction of Pt/Graphene as Catalyst

The increasing in energy needs and the lack of non-renewable energy sources becomes a challenge for the human being to be able to use renewable energy sources. One of the devices to process renewable energy is Polymer Electrolyte Membrane Fuel Cell (PEMFC) . PEMFC use hydrogen and Oxygen as an energy sources . The most important reaction in fuel cell is Oxidation and reduction process. Therefore, a catalyst is needed to help the OR process. Study of catalyst shows that the most effective fuel cell for now is Platinum. Many fuel cell have use platinum as the catalyst. However, Platinum is a rare and expensive element. Therefore, to reduce the cost of fuel cell fabrication, we need to increase the activity of platinum. In this research, we use graphene as a support material. Then, we will study about the interaction of platinum on graphene and analyze its morphological change and electronic properties.The research conduct using Density Functional Theory (DFT). The calculation result shows that Pt/graphene can break H2 into H+ and the binding between Pt cluster is stronger than binding with the substrate.

Density Functional Theory (DFT) Study of Molecularly Imprinted Polymer (MIP) Methacrylic Acid (MAA) with D-Glucose

In order to find an alternative biosensor material which enables to detect the glucose level, therefore in this study, the interaction between Methacrylic Acid (MAA) based Molecularly Imprinted Polymer (MIP) with D-Glucose is investigated using the Density Functional Theory (DFT). The aim of this study is to determine whether a molecule of the MAA can be functioned as a bio-sensing of glucose. In this calculation, the Gaussian 09 with B3LYP and 631+G(d) basis sets is used to calculate all electronic properties. It is found that the interaction between a molecule of MAA and a molecule of D-Glucose was observed through the shortened distance between the two molecules. The binding energy of MAA/D-glucose and the Mulliken population analysis are investigated for checking possible interaction. From analysis, the MAA based MIP can be used as a bio-sensing material.

A comparative study of flat coil and coil sensor for landslide detection

The landslide is one of the most costly catastrophic events in terms of human lives and infrastructure damage, thus an early warning monitoring for landslides becomes more and more important. Currently existing monitoring systems for early warning are available in terms of monolithic systems. This is a very cost-intensive way, considering installation as well as operational and personal expenses. We have been developing a landslide detection system based on flat coil and coil sensor. The flat coil element being developed is an inductive proximity sensor for detection mass of soil movement. The simple method of flat coil manufactures and low cost, is an attraction that is still inspired to develop flat coil sensors. Meanwhile, although it has a drawback in terms of their size, the coil sensor is still required in many fields due to their sensitivity and robustness. The simple method of coil manufacture and the materials are commonly available and low cost, is an attraction that is still inspired to develop induction coil sensors. A comparative study of alternative configuration of sensor based on flat coil elements and a coil in application to landslide detection has been discussed in this paper. The purpose of this comparison is to show the ideal conditions and the challenges for each sensor. Furthermore, a comparison between flat coil and coil sensor is presented.The landslide is one of the most costly catastrophic events in terms of human lives and infrastructure damage, thus an early warning monitoring for landslides becomes more and more important. Currently existing monitoring systems for early warning are available in terms of monolithic systems. This is a very cost-intensive way, considering installation as well as operational and personal expenses. We have been developing a landslide detection system based on flat coil and coil sensor. The flat coil element being developed is an inductive proximity sensor for detection mass of soil movement. The simple method of flat coil manufactures and low cost, is an attraction that is still inspired to develop flat coil sensors. Meanwhile, although it has a drawback in terms of their size, the coil sensor is still required in many fields due to their sensitivity and robustness. The simple method of coil manufacture and the materials are commonly available and low cost, is an attraction that is still inspired to develop...