Sharp edges schottky contact electric field simulation

This paper reports investigation on effect of adding sharp edges to Schottky contact. Few studies suggested that sharp edge nanostructures produces high electric field which subsequently improve gas sensing performance on reversed biased mode. Three different shapes: circular-, hexagon- and star-shape were modeled by using COMSOL Multiphysics. The study on effects of different sizes sharp edges Schottky contact also reported. Electric field was observed and it shows that star-shape yields highest summation of electric field 2.79 x 109 V/m and lowest electric field observed at circular-shape 7 x 107 V/m. The results also revealed that distance of sharp edges from substrate edge affects the magnitude of electric field

Characteristic of Thin Sheet Membrane for a Mechanical Driven Micropump System

This paper demonstrates the characteristic of thin sheet membrane for a mechanical driven micropump system by using a spin coater machine. The moving diaphragm material is made from a PDMS prepolymer material. A 100 mm diameter petri dish is used as the mold template for the membrane fabrication. There are three variables that influence the membrane thickness formation during the spin coating process, which are the prepolymer weight, spin coater spinning rate speed and the spinning time. Based on the study, the optimum parameters to fabricate a 300 µm thin sheet membrane by using a 100 mm diameter of petri dish are 2.5 g of prepolymer, 500 rpm of spin coater speed and 180 s of spin time. These parameters yield a thin sheet membrane for the micropump application with 314.82 ± 3.6556 µm thickness

Harvesting Electrical Energy from Rooftop Ventilator

Development of the renewable energy is one of the most challenging issue in Malaysia since the fossil fuels and natural gas is foresee to be depleted in one day. Renewable energy is able to provide sustainable yet clean energy to the country in the near future. Other than Solar, wind energy is only of the renewable energy that has the potential to provide green energy to not only domestic but industrial users. This paper proposes a development of similar concept of wind energy by harvesting electrical energy from rooftop ventilator. Modification is made on a commercial rooftop ventilator with an integration of a 120V DC motor and conversion gear (gear ratio 1:2) to the turbine shaft. The continuous rotation of the rooftop ventilator due to temperature difference indoor and outdoor rotated the rotor of the DC generator. The DC energy is stored in the battery via a charge controller before distributing to the load. An average of 60 rpm turning speed of the ventilator is simulated mimicking the general turning speed of the ventilator installed on the roof. The generated energy characteristics study is carried out by using standard fan to produce steady rotational of the ventilator. As the spin rate is very low to reach the optimum spin rate, the generated energy is small and only for a small DC load

Does parallel projection is suitable in electrical capacitance tomography? -A comparison with common approach

Electrical Capacitance Tomography (ECT) is one of the soft field tomography that widely used for the purpose of measurement and monitoring of multiphase flow. Common problem of the soft field tomography is low quality and unstable images in the pipe especially at the center section of the pipe. In this paper, an ECT system with a comparison between common approach and a parallel approach is presented. Simulation in 2 dimensions with 16-electrode is carried out to observe a potential projection. The COMSOL Multiphysics software is used to investigate the state and response of the electric field with this approach by exporting data with 128x128 pixels. Air bubbles as a phantom in the oil medium have been tested and analyzed. Linear Back-Projection Algorithm (LBP) is implemented using MATLAB software to obtain a tomogram. A Multi Scale Structural Similarity, MSSIM was applied to compare both approaches. Consequently, the resolution and quality of the pictures in the pipes can be distinguished. However, a further investigation is needed to improve the parallel approach for ECT system

Does parallel projection is suitable in electrical capacitance tomography

Electrical Capacitance Tomography (ECT) is one of the soft field tomography that widely used for the purpose of measurement and monitoring of multiphase flow. Common problem of the soft field tomography is low quality and unstable images in the pipe especially at the center section of the pipe. In this paper, an ECT system with a comparison between common approach and a parallel approach is presented. Simulation in 2 dimensions with 16-electrode is carried out to observe a potential projection. The COMSOL Multiphysics software is used to investigate the state and response of the electric field with this approach by exporting data with 128x128 pixels. Air bubbles as a phantom in the oil medium have been tested and analyzed. Linear Back-Projection Algorithm (LBP) is implemented using MATLAB software to obtain a tomogram. A Multi Scale Structural Similarity, MSSIM was applied to compare both approaches. Consequently, the resolution and quality of the pictures in the pipes can be distinguished. However, a further investigation is needed to improve the parallel approach for ECT system

Genetic algorithm techniques for the design of nonlinear microwave circuits

Steady state analysis of nonlinear circuits represents the most computational challenging problem in RFMcrowave circuit design. Even though all circuits are assumes as a linear circuits in circuit theory, in fact it is nonlinear circuit. The problem in designing and analyzing the nonlinear circuits usually more complicated than for linear circuits. Many approaches have been done to overcome this problem. Recently hybrid method of analyzing nonlinear circuits has proved to be popular. In this report a hybrid method of Sample Balance Genetic Algorithm (SBGA) used to analyze nonlinear diode excited by RF circuit. The purpose of this report is to minimizing the current difference between nonlinear current which across the nonlinear element and linear current at linear element and voltage across the nonlinear terminal. By using Sample Balance's differential of current linear and nonlinear equation as an objective function, a Genetic Algorithm routine then been constructed. Genetic Algorithm will then recombine, mutate and evaluate the population of solution to find the best solution based on Sample balance equation. This hybrid method manages to get 0.013A of error current and a sinusoidal waveform clipped at 0.W during first half of the wavefonn for the nonlinear voltage

In-column electrochemical detection for liquid chromatography microdevice

Liquid chromatography is a pressure driven separation method for chemical mixture: different affinities of the analytes for the mobile phase and the stationary phase under pressure will cause separation of analytes as diverse as proteins (Oates and Jorgenson 1990) to neurotransmitters (McKenzie et al. , 2002

Hydrogen gas sensor based on highly ordered polyaniline/multiwall carbon nanotubes composite

In this work, the structural and gas sensing properties of an electropolymerized, polyaniline (PANI)/multiwall carbon nanotube (MWNT) composite based surface acoustic wave (SAW) sensor are reported. Thin films made of PANI nanofibers were deposited onto 36 lithium tantalate (LiTaO3) SAW transducers using electropolymerization and were subsequently dedoped. Scanning electron microscopy (SEM) revealed the compact growth of the composites which is much denser than that of PANI nanofibers. The PANI/MWNT composite based SAW sensor was then exposed to different concentrations of hydrogen (H2) gas at room temperature with a demonstrated electrical response

Polyvinylpyrrolidone/multiwall carbon nanotube composite based 36 degrees YX LiTaO(3) surface acoustic wave for hydrogen gas sensing applications

Poly-vinyl-pyrrolidone (PVP) /Multiwall Carbon Nanotubes (MWNTs) based Surface Acoustic Wave (SAW) sensors are fabricated and characterized, and their performances towards hydrogen gas are investigated. The PVP/MWNTs fibers composite are prepared by electrospinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nanostructure material is observed. From the dynamic response, frequency shifts of 530 Hz (1% H(2)) and 11.322 kHz (0.25% H(2)) are recorded for the sensors contain of 1.525 g and 1.025 g PVP concentrations, respectively

Polyvinylpyrrolidone/polyaniline composite based 36° YX LiTaO3 surface acoustic wave H2 gas sensor

Poly-vinyl-pyrrolidone (PVP)/polyaniline based surface acoustic wave (SAW) sensors were fabricated and characterized and their performances towards hydrogen gas were investigated. The PVP/polyaniline fibers composite were prepared by electrospinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nanostructure material was observed. From the dynamic response, frequency shifts of 6.243 kHz (1% H2) and 8.051 kHz (1%were recorded for the sensors deposited with PVP/ES and PVP/EB, respectively