Rancangan Area Serapan Air Pada Pemodelan Potensial Listrik Topografi Landai

Measure natural electric voltage at surface used Self-Potential method. Self-Potential one of the methods used to look at subsurface water flow. The negative or positive sign of potential is an important factor for the interpretation of Self-potential anomalies. The finite element technique is applied to model the velocity of water flow, current source, and potential value distribution in the form of  2-D profile. Finite element technique was chosen to solve the problem of boundary conditions and differential equations for Self-Potential modeling. Modeling current sources are obtained by intermediate gradient operation and water flow velocity . From the result of modeling, we get the value of water flow velocity between 10-6 - 10-4 m/s, current source, potential distribution, and potential response on the topography of the slope. Each topography produced different potential response forms, due to the electrokinetic effect. The water flow in the area with slopes topography often causes inundation due to inadequate absorption area, thus causing the grinding of the soil and destroying the road. From the results of this modeling is designed a good water absorption area using visio

Octafilar Helical Antenna for Portable UHF-RFID Reader

Octafilar helical antenna (OFHA) is proposed for handheld ultra‐high‐frequency (UHF) radio frequency identification (RFID) reader. The investigated antenna configuration consists of OFHA placed on reader device in the presence of human hand model. The antenna is designed at UHF band centered at 915 MHz. The antenna return loss, axial ratio, gain, co‐polarized and cross‐ polarized field components are calculated using the finite element method (FEM) and compared with that calculated by finite integration technique (FIT) for verification of the simulated results. A comparison between the performance of the quadrifilar helical antenna (QFHA) and the octafiliar helical antenna (OFHA) designed at 915 MHz in the presence of the reader device and human hand model is investigated. The OFHA introduces high gain, high front to back ratio, good axial ratio and omnidirectional coverage

Computational Analysis of the Maximum Optical Enhancement of Gold Nanowires and Nanowire Arrays

Plasmonic devices have gained popularity recently due to their unique ability to focus light to scales smaller than the diffraction limit and amplify the intensity of incident light. One such plasmonic device is the gold nanowire, a simple geometry that can be fabricated into a variety of geometric patterns. The aim of this project was to determine the effect of nanowire geometry on its maximum optical enhancement. For this purpose, the plasmonic optical enhancement properties of single gold nanowires and triple nanowire arrays were investigated using finite element method simulations. The results of the simulations indicate a significant effect on the optical enhancement of both the thickness and width of the nanowires. From the simulation data, an equation for each geometry (single and triple array) was found that relates the dimensions and incident wavelength to the optical enhancement. These equations can be used while designing nanowires to optimize the dimensions and provide the maximum possible optical enhancement

Análise de vigas sobre base elástica via métodos variacionais

The study of beams is one of the main problems investigated in Civil Engineering, and these structures are governed by differential equations. This article seeks to identify numerical solutions of the balance equation of beams on elastic basis, using the Finite Element Method and applying the variational methods, i.e., Placement, Sub-regions and Least Squares Method, aiming to compare the results obtained through numerical experiments and the analytical solution, to identify the variational method that provides the best approximate solution, befitting the analytical solution. This is a bibliographic review, with descriptive approach and numerical simulations using the programming language, Phyton. We compared the solutions of the model problem for two different cases, using the methods mentioned above, noting that in the 1st case, the Methods of Sub-regions and Placement provide the best approximation for vertical displacements, with a polynomial base function, while in the 2nd case the trigonometric function provides a better approximation, presenting significant variations in relation to the 1st case, due to changes in parameters, spring coefficient (K), modulus of longitudinal elasticity (E) and cross-sectional inertia (I). Thus, starting from this formulation, other problems frequently encountered in engineering can be analyzed, such as continuous beams and dynamic analysis of beams.O estudo de vigas é um dos principais problemas investigados na Engenharia Civil, sendo estas estruturas regidas por equações diferenciais. Este artigo busca identificar soluções numéricas da equação de equilíbrio de vigas sobre base elástica, utilizando o Método dos Elementos Finitos e aplicando os métodos variacionais, a saber, Colocação, Sub-regiões e Método dos Mínimos Quadrados, visando comparar os resultados obtidos através de experimentações numéricas e a solução analítica, para identificar o método variacional que fornece a melhor solução aproximada, condizente com a solução analítica. Trata-se de uma revisão bibliográfica, com abordagem descritiva e realização de simulações numéricas utilizando a linguagem de programação, Phyton. Comparamos as soluções do problema modelo para dois casos diferentes, utilizando os métodos citados anteriormente, constatando que no 1° caso, os Métodos das Sub-regiões e Colocação fornecem a melhor aproximação para os deslocamentos verticais, com uma função base polinomial, enquanto no 2° caso a função trigonométrica fornece uma melhor aproximação, apresentando variações significativas em relação ao 1° caso, devido às mudanças nos parâmetros, coeficiente de mola (K), módulo de elasticidade longitudinal (E) e inércia da seção transversal (I)

Modeling edge effects of mesa diodes for silicon photovoltaics

A mesa diode has been modeled and its performance under dark and illuminated conditions has been simulated using a commercial finite element software package. These simulations have led to a determination of the self-consistent solution to the continuity equations for electrons and holes using the steady-state drift-diffusion model for carrier dynamics coupled with electric potential determined from Poisson\u27s equation. The purpose of these simulations has been to determine the influence of edge conditions on the overall performance of mesa diodes under dark and illuminated conditions. Mesa diode arrays are fabricated on crystalline silicon solar cells. They are an array of small area solar cells that are electrically isolated from one another. They can be probed to spatially measure the current density vs. voltage curves under dark and illuminated conditions. The underlying models of bulk and surface recombination mechanisms have been well established for crystalline silicon based semiconductor devices such as the mesa diode. However, the combination of these phenomena that occur during the simulation of the operation of the mesa diode results in a unique edge effect that can significantly change the overall performance of the mesa diode. In particular, the simulations performed show that the space charge region becomes extended along the vertical edge of the mesa diode due to the fixed positive surface charge. At the intersection of the vertical edge and step, a strong electric field is produced because it has a small convex radius of curvature. Depending on the sharpness of this intersection, the entire device can become significantly shunted. Simulations have been performed with a sharp corner and a smooth curve at the intersection of the vertical edge and the step. The use of a smooth curved transition results in significantly lower dark current density vs. voltage and a greater open circuit voltage and fill factor under illumination. Yet, even with a curved transition, the space charge region can extend approximately 100 microns into a 199.5 micron thick mesa diode, and have a bulk recombination rate that is two orders of magnitude greater than the rest of the device at low forward biases

Evaluation and comparison of FEM and BEM for extraction of homogeneous substrates

In the design and fabrication of micro-electronic circuits, it is necessary to simulate and predict many kinds of effects, such as substrate crosstalk, interconnect delays and others. In order to simulate and predict properly these effects, accurate and efficient substrate modeling methods are required. Substrate resistance extraction involves finding a resistance network between ports correctly describing the behaviour of the substrate. In this report we consider the problem of resistance extraction of a substrate with a homogeneous doping profile. We solve the problem by means of two discretization methods, namely the finite element method (FEM) and the boundary element method (BEM) and discuss the advantages and disadvantages of each of these methods. We particularly addresses the problem of achieving grid-independent results and characterize the cases in which one technique is better than the other

Circular Polarized Dielectric Resonator Antenna for Portable RFID Reader Using a Single Feed

A new design of circular polarized elliptical dielectric resonator antenna (DRA) with single feed for handheld radio frequency identification (RFID) reader is presented. The elliptical dielectric resonator antenna with an aspect ratio of 1.5 is used. This design has achieved 66.7 MHz impedance bandwidth (for S11 < ‐10 dB) by using material with dielectric constant material (εr = 12) in conjunction with coaxial probe feed in free space. The DRA models are simulated using two different numerical techniques, the finite element method and the finite integral technique.  The numerical results of the two different computational methods approache are investigated and compared. The results are in good agreement within the desired frequency band, 5.65 GHz – 5.95 GHz. A model for a handheld RFID reader device including the elliptical DRA in the presence of human hand models is, also, investigated. The return loss is <10 dB over the frequency range of 5.49‐  6.967 GHz resulting in frequency bandwidth of 1.47 GHz. A high front to back ratio and gain of 5.726dBi are obtained

Plasmonic Waveguides to Enhance Quantum Electrodynamic Phenomena at the Nanoscale

The emerging field of plasmonics can lead to enhanced light matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single photon quantum light that can be employed as a quantum bit or qubit in the envisioned quantum information technologies. We demonstrate different ways to enhance a diverse range of quantum electrodynamic phenomena based on plasmonic configurations by using the classical dyadic tensor Green function formalism. More specifically, spontaneous emission and superradiance are analyzed by using the Green function based field quantization. The exciting new field of quantum plasmonics will lead to a plethora of novel optical devices for communications and computing applications operating in the quantum realm, such as efficient single-photon sources, quantum sensors, and compact on-chip nanophotonic circuits