····· lezzter Preis 71.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This book has investigated radioclimatological study in a clear-air environment as applicable to terrestrial line of sight link design problems. Radioclimatological phenomena are adequately reviewed both for the precipitation effect and clear-air effect. The research focuses more on the clear-air effect of radioclimatological studies. Two Southern African countries chosen for case study in the report are Botswana and South Africa. To this end, radiosonde data gathered in Maun, Botswana and Durban, South Africa are used for model formulation and verification. The data used in the book ranges from three years to ten years in these two stations. Three to ten years of refractivity data gathered in Botswana and South Africa is used for the model formulation. On the other hand, eight months signal level measurement data recorded from the terrestrial line of sight link set up between Howard College and Westville Campuses of the University of KwaZulu-Natal, Durban South Africa is used for model verification. ····· 1036125488
····· lezzter Preis 53.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Spintronics is an area of electronics that studies the design of electronic devices based on the spin properties of electrons, taking advantage of their full potential. To date, despite the extended theoretical work done on this class of components, models are mainly physical and, due to their extreme complexity, cannot be implemented in circuit simulators. The aim of this work is to address the critical problems of modeling spintronic devices in a compact form. The main goal is to make a bridge between a purely physical description and a more electrical counterpart of spintronic elements in order to enable their use in Computer Assisted Design tools, just as for CMOS devices. The first part of the book gives an introduction to the different kinds of spin-orbit interactions, the materials used for realizing spintronic devices and the main spin-based devices currently developed. The second part is then dedicated to the modeling of simple transistor structures where the current depends on spin-polarized carriers. Moreover, a brief outlook on possible future spintronic devices is given. ····· 1036125431
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This manuscript describes different methods for transferring, in the most efficient way, power from the solar cells to the battery system, and from the battery system to all loads..Since overcharging a battery can cause damage to the battery, this project describes/analyzes DC-DC Buck choppers that will not just reduce/regulate the voltage for solar cell charging.. In order to understand the use of PI controller in minimizing the output voltage oscillation cycles and its magnitude, the model is provided with a manual switch and PI controller. Using the manual switch provided, the model of a time varying DC voltage source is provided as the input to simulate the effect of variation of the input voltage from its normal value. Thus we can visually observe the effect of variation of input voltage on the output, both by including and excluding The PI controller in the same model. This report is intended to provide the designer with a method of buck/step down DC voltage from high Voltage to low Voltage, by using a DC-DC switching buck chopper designed specifically for this task, the results are validated by using MATLAB/SIMULINK. ····· 1036125155
····· lezzter Preis 61.20€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Thin-film silicon solar cell is a promising technology for solar energy due to their low-cost large-scale manufacturability, but one of the major challenges is to absorb light at infrared wavelengths where the absorption length is much larger than the active layer thickness. This book overviews the state-of-the-art light trapping technology for efficiency improvement in thin-film Si solar cells. we propose an all-dielectric, textured photonic crystal (TPC) as an effective light trapping scheme, which integrates dielectric gratings and a distributed Bragg reflector (DBR) in the backside of thin film silicon. We understand the operation principles for this design by using photonic band theories and electromagnetic wave simulations. We also developed a self-assembled method to fabricate the proposed photonic structures. Finally, we explored the fundamental performance limits for thin-lm Si solar cells. ····· 1036124945
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This book deals with analysis and simulation of ZVT based Boost PFC Converter with EMI Filter in PSpice software of version 9.2.The Boost converter of Power Factor Correction (PFC) Circuit is analyzed, designed and then simulated for resistive load. It gives better power factor at the input side and constant voltage and current at the output side. The drawback is the current has more noise i.e. EMI.The power factor is further improved using ZVS technique. In the converter circuit, the active clamping branch composed of a clamping capacitor and an active switch is placed in parallel with resonant inductor. Also, the main switch, the auxiliary switch, the clamping capacitor, the boost diode and the output capacitor form a voltage loop. The power factor is further improved using ZVT technique.The ZVT technique allows the increase in switching frequency without increase in switching losses .ZVT converter operates at a fixed frequency while achieving zero voltage turn on of the main switch and zero current turn off of the boost diode.In this book,it is proposed that ZVT based Boost PFC Converter with EMI Filter is a better solution for power factor improvement in AC to DC Converters. ····· 1036124838
····· lezzter Preis 26.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Este libro está dirigido a trabajadores de redes, empresas de energía, centros de capacitación, educadores técnicos, estudiantes, técnicos y a profesionales de la industria representando una introducción indispensable para contribuir a implementar prácticas, cumplir normas y seguir pasos necesarios para trabajar de una manera segura con tensión en redes de distribución y transmisión una fuerza de talento técnico-artesanal especializada utilizando equipos y herramientas modernas, aumentando así la seguridad laboral, la eficiencia de maniobras y poder ofrecer un valor agregado a empresas de energía a nivel global. Asimismo, se presenta de una manera sencilla los aspectos más importantes relacionados con la capacitación y seguridad laboral requerida en Transmisión y Distribución con el objetivo de mejorar niveles de calidad del servicio y satisfacer las necesidades cada vez más exigentes de los consumidores y sus demandas por alcanzar un buen servicio sin interrupción en el siglo XXI. ····· 1036124272
····· lezzter Preis 35.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Para desarrollar la aplicación del efecto corona en materiales cerámicos, en la Universidad Central y desde el grupo ESSOPTO, se diseñó y desarrolló una cámara de descarga con electrodos flotantes en donde se simularon las condiciones de atmósferas densas y el comportamiento del campo eléctrico. Las pruebas experimentales desarrolladas y las simulaciones obtenidas en el proceso de investigación, se compararon con los modelos teóricos reportados en la literatura, logrando con lo anterior, optimizar el proceso de preparación de las muestras cerámicas objeto de estudio. La técnica empleada de efecto corona, condujo a mejorar la conductividad térmica y eléctrica de las muestras que después fueron empleadas para la fabricación de sensores de humedad relativa de piso y aire. ····· 1036123180
····· lezzter Preis 88.20€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray El aporte principal de este libro consiste en el desarrollo de una metodología basada en Economías Computacionales de Agentes, para modelar el comportamiento de los precios de oferta en el Mercado Eléctrico Colombiano. Esta metodología implica el desarrollo de distintos algoritmos de aprendizaje para los agentes que interactúan de manera repetida en el mismo. Como resultado final, se desarrolló un laboratorio experimental de interacciones entre los agentes generadores, los cuales exhiben capacidades adaptativas que les permiten mejorar, de manera autónoma, sus estrategias de oferta. La plataforma de simulación desarrollada permite experimentar con nuevas propuestas de diseño del mercado, que parten desde la diferenciación de cada central, hasta un modelo explícito de las restricciones operativas representadas por las redes de transmisión en Colombia. ····· 1036122969
····· lezzter Preis 35.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray En este trabajo se presenta un estudio sobre heteroestructuras compuestas por la combinación de al menos dos redes cristalinas con diferente estructura de bandas. Cada una de las redes presenta bandas de energía permitida y bandas de energía prohibida. Las bandas de energía prohibida se encuentran ubicadas en longitudes de onda que tienen un tamaño similar a la periodicidad del cristal. La idea general de este trabajo es la de sumar las bandas de energía prohibida para obtener una heteroestructura con un rango de frecuencias prohibidas gigante. Presentamos una extenso estudio de los métodos de cálculo de la estructura de bandas y de las propiedades ópticas. Las ideas presentadas en este libro pueden ser aplicadas al estudio de otro tipo de heteroestructuras, tales como las heteroestructuras fonónicas y de metamateriales. ····· 1036122703
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray En este trabajo se presenta el estado del arte en lo relativo al daño óptico en materiales fotorrefractivos. Entender este fenómeno es de gran relevancia debido a que afecta a un número importante de aplicaciones fotónicas, que podrían significar el futuro de las telecomunicaciones. Para ello en este documento se lleva a cabo un estudio riguroso experimental de este fenómeno y se desarrolla un modelo teórico para explicarlo. La combinación de ambas aproximaciones (teórica y experimental) logra explicar de manera detallada al daño óptico, permitiendo tener el conocimiento necesario para generar aplicaciones donde se puede controlar totalmente la aparición de este efecto tan dañino, aumentando la eficiencia de operación y la vida útil de los dispositivos. ····· 1036122592
····· lezzter Preis 71.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Los conductores aéreos de altas prestaciones térmicas y flecha pequeña son aquellos cuya temperatura de funcionamiento en régimen permanente es más elevada que la de los conductores convencionales, como el ACSR, cuya temperatura máxima está en torno a los 90 ºC. La sustitución de los conductores convencionales por otros de altas prestaciones térmicas y flecha pequeña se presenta como una alternativa que tiene varias ventajas frente a los métodos de repotenciación tradicionales. La principal virtud de esta sustitución es que la repotenciación se puede obtener sin necesidad de una actuación sobre los apoyos y cimentaciones. El presente trabajo de investigación, realizado en el seno de la Unidad de Formación e Investigación de la UPV/EHU CINIERSE, describe las características de estos conductores y revisa los métodos de cálculo mecánico y térmico considerando su aplicación a dichos conductores. Además, se propone una metodología de cálculo más adecuada para estos conductores. El contenido del libro debe resultar muy útil para los profesionales e investigadores del campo del transporte y distribución de energía eléctrica. ····· 1036122509
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray La interacción de la luz con la materia se manifiesta con gran diversidad, tanto que actualmente surgen publicaciones científicas describiendo sistemas con una nueva propiedad óptica. Sin embargo, las ecuaciones que describen al electromagnétismo se han establecido desde hace mucho tiempo. Claramente, el descubrimiento de nuevas propiedades ópticas está relacionado con la capacidad tecnológica de hoy en día en combinar los materiales disponibles y realizar compuestos de los mismos con formas y tamaños en la escala adecuada. Para entender dichas propiedades se debe afrontar el problema de representar tales morfologías y su interacción electromagnética. Una estrategia natural de hacer esto es imaginando al sistema compuesto por partes que podemos identificar con mayor o menor precisión dependiendo de que tanto nos acerquemos al mismo. En este trabajo abordamos computacionalmente ese problema para el caso de cúmulos de partículas nanométricas metálicas. Obtenemos que la intensidad de luz esparcida escala con el ángulo de dispersión sólo a partir de un tamaño mínimo que depende de la disipación de energía electromagnética cuando se excitan las resonancias ópticas del cúmulo. ····· 1036122332
für 35.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Hoy en día las aplicaciones de sistemas de comunicación satelitales demandan un mayor ancho de banda, mayor integración de componentes y una mayor potencia de entrada. Estos tres requerimientos implican mayores densidades de campo eléctrico dentro de los dispositivos. Por eso es indispensable analizar su impacto en la operación normal de un satélite por medio de modelos teóricos y su interpretación en programas computacionales. Existen muchos fenómenos que limitan la capacidad de un subsistema dentro de un satélite de aumentar su potencia. En particular, los más relevantes son, en componentes pasivos, intermodulación pasiva (PIM), descarga corona y ruptura multipactor. En este trabajo se analiza el efecto corona en filtros tipo Ku y guías de onda rectangulares empleados en SAT-COM con aislamiento en aire atmosférico, considerando la respuesta de los dispositivos a bajas y altas presiones. Se discute la variabilidad de las frecuencias de colisión entre electrones y moléculas de aire y, en su caso, la presencia de humedad. Se muestran y analizan las ecuaciones que describen el comportamiento de la descarga corona y se comparan con simulaciones de la ruptura de los dispositivos. ····· 1036122022
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray One of the most serious problems in measurements electrical power systems is the possibility of over-voltages resulting from ferroresonance phenomenon. This can result in high overvoltages that can cause insulation failures in transformers, cables, and arresters. Ferroresonance is a general term applied to a wide variety of interactions between capacitors and iron-core inductors that result in unusual voltages and/or currents.This work is aimed at proposing a simplified model of ferroresonance phenomenon in single phase power transformers and analyzing the instantaneous wave shapes of voltage and current being distorted by the ferroresonance phenomenon by solving the Doffing equation. The transformer is modeled and the non linear equivalent resistance and inductance of the magnetizing branch are determined from open circuit test. The ferroresonance resulting from energizing the transformer through a series capacitor is assessed and the calculated primary voltage, input current, active power, reactive power and power factor values are compared with those measured experimentally. ····· 1036121481
für 49.41€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray The rate of Iraqi power demand has been increased significantly faster than the infrastructure`s development and it becomes very difficult to keep the system stable especially with the current acts of vandalism against the country, so it`s very important to improve the power system stability. The object of this work is to improve the stability of the Iraqi National Super Grid System (INSGS) by installing Unified Power Flow Controller (UPFC) devices in different optimal locations under fault condition and comparing the results with those of without UPFC devices under the same condition. The optimal location of the UPFC device was specified based on Genetic Algorithm (GA) optimization method, it was utilized to search for optimum UPFC parameters setting and location based objective function that depends on the power and voltage as a fitness constraints. The results obtained showed that the installation of Unified Power Flow Controller (UPFC) devices at the optimal locations of the Iraqi grid gives an improvement in the stability by damping the voltage and rotor angle oscillations after subjected to the three phase fault to ground at different locations and different cases. ····· 1036121289
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray The fast growth of wind generation has led to concern about the effect of wind power on the transient stability of the electric grid. New studies must be performed in order to evaluate the behaviour of the wind farms after severe faults and improve the design of the wind farms in an efficient and economical way. Under such circumstances, the most demanding requisite for wind farm is the Fault Ride-Through (FRT) capability. Wind farms connected to high voltage transmission system must stay connected when a voltage dip occurs in the grid, otherwise, the sudden disconnection of great amount of wind power may contribute to the voltage dip, with terrible consequences. Therefore, the dynamic and transient analyses of wind generators are necessary. This book proposes some methods with suitable control strategies for wind power application that helps wind farms to be connected during grid disturbances, achieving the grid code provisions in both steady and transient conditions. The results in this book can be significant in understanding the transient stability phenomena of fixed and variable speed wind turbines and also in designing of wind farms based on transient stability requirements. ····· 1036121243
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Around the world, there are a number of policies encouraging penetration of wind generation in the electricity industry. The proposed large increase in the penetration of wind generation has raised concerns about the continued security and reliability of the operation of the network. Together with the uncertainty associated to the generation of wind energy, the demand for balancing services is increasing. Under these windy scenarios, it might be more efficient to use preventive actions in the spot market rather than doing corrective actions in the market for balancing services. This book aims at showing the advantages of this new paradigm of the organization of the electricity market. With this purpose, an integrated model of the electricity market was built on the optimization GAMS software and run for different environments and configurations of the grid. Comparisons are made at the end of this document in order to point out the superiority of this new approach over the traditional corrective model. ····· 1036121165
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Microbial fuel cell technology is an emerging technology with the potential to support renewable energy production and promote sustainable development. However, high cost of materials has militated against large scale implementation of this technology, especially when considering the high cost of Nafion used as proton exchange membrane. The successful application of Plaster of Paris slurry(gypsum) as proton exchange membrane as highlighted in this work, suggests the possibility of reduced cost in the development of this technology. Also, the architectural design described in this work makes this technology accessible to professional and non professionals interested in this research area. In addition, non governmental organizations (NGO`s) interested in the development of renewable technology for developing countries will find this simple and cost effective design very appealing. ····· 1036121083
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray In this text book,the performance comparison of various Apodization profiles in terms of side lobe suppression is investigated.This research is aimed to develop the mathematical model of the Apodized Fiber Bragg Grating Scheme in order to suppress side lobes, while maintaining the reflectivity and narrow bandwidth. MATLAB codes are written to solve the coupled mode equations for the analysis of optimized reflection spectra under Fiber Bragg grating Strain Sensor.Finally the simulation results of MATLAB are compared with the results obtained by the standard software of Opti-grating version 4.2. ····· 1036120935
für 61.20€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This work is an investigation and study of the mechanism of internal discharges in micro cavities in solid dielectrics with application to power cables. The magnitude, repetition rate and energy, in micro cavities in solid dielectric samples and electrical cables were studied. The field distribution in these cavities was simulated, modeled and calculated for certain applied voltage. Alternating high voltage at power frequency at room temperature was applied to different materials.The cavity shape, cylindrical or spherical, and its dimensions were changed. The size of the cavity was much smaller than the sample thickness. The cavities location and w.r.t electrodes were changed. The study was done on samples of low density polyethylene (LDPE), polyvinylchloride (P.V.C) and ethylene polypropylene rubber (E.P.R) because of their important industrial applications. ····· 1036120912
für 32.31€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray An average-value model of a rotating rectifier circuit in a brushless excitation system is set forth,where a detailed simulation is required to extract the essential averaged-model parameters usingnumerical averaging. In the proposed approach, a synchronous machine model with saturation and cross saturation and an arbitrary rotor network representation that uses a voltage-behind-reactance representation for the field winding of the main machine is proposed. ····· 1036120789
für 32.31€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Turnkey projects have been highly regarded yet the adoption of the approach in the implementation of projects by majority of organizations in Kenya is still very low. The aim of this study was to investigate the factors that influence the adoption of turnkey approach in implementation of projects in Kenya. The study adopted a descriptive survey research design. The target population comprised the 37 staff working for Projects departments using census technique. Data was collected through a questionnaires structured using both open ended and closed ended. Chisquare( X2) analysis was used to investigate the associations between the variables. Statistical Package for Social Sciences (SPSS) was used for the analysis. The finding of the study shows a significant relationship between contractors capacity, organizational policies and terms of reference for turnkey projects and the adoption of turnkey project implementation. Project costs were not found to have significant association with the adoption of the turnkey project implementation approach. The study recommends the development of local contractors capacities technically to meet KPLC expectations for implementing turnkey projects. ····· 1036120419
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Single-core underground power cables can induce voltages and currents in their metallic sheaths. The sheath induced currents are undesirable and generate power losses and reduce the cable ampacity whereas the induced voltages can generate electric shocks to the workers that keep the power line. This means that it is very important to know the values of sheath currents and induced voltages and the factors affecting them.So this bbbkdiscussed the following: - Calculations of the induced voltages in single-core cables with various voltages levels from 11 kV to 500 kV with briefly studying the factors affecting them. - Studying the factors affecting the sheath losses in single-core cables by calculating the sheath currents (eddy-circulating) and their sheath losses in single-core cables with various metallic sheath materials with taking into consideration the following factors: Types of sheath bonding methods (single-point bonding, two-points bonding, cross bonding) and cable layouts (trefoil, flat), cable parameters, cable spacing, sheath resistance, phase rotation, conductor current, power frequency, the minor section length in cross bonding. ····· 1036120410
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray DC to DC power converters find major applications in all central processing unit (CPU) power supplies. The modern trend is to go towards lower power supply voltages the reason for this is to limit power at high clock frequencies (in GHz) employed. The current demanded by the processors are high. On account of this development there is a great demand for DC to DC converters with low output voltages and high currents. Typically the operating voltage is 1.5V or less and current levels are higher than 50A as specified for the forthcoming INTEL P4 chips. The low voltage, high current power supplies have the option of powering from a 12V bus [1] or 48V bus [2]. The required efficiency of the power supply has to be greater than 80%. The challenge in such converters is achieving high efficiency. This thesis addresses the challenges involved in the design of efficient low voltage, high current DC to DC power supply. Synchronous rectifiers are used as a standard method for achieving high efficiency in low voltage output converters. This thesis, besides employing synchronous rectifiers, proposes two additional innovations towards the goal of high efficiency. ····· 1036120195· 1 ·· 2 ·· 3 ·· 4 ·· 5 ·· 6 ·· 7 ·· 8 ·· 9 ·
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