Bøger af Susarla Venkata Ananta Rama Sastry

Com o advento dos dispositivos de comutação de semicondutores de potência, como os tiristores, os GTO (Gate Turn off thyristors), os IGBT (Insulated Gate Bipolar Transistors) e muitos outros dispositivos, o controlo da energia eléctrica tornou-se uma realidade. Estes controladores electrónicos de potência são amplamente utilizados para alimentar cargas eléctricas, tais como variadores de velocidade ajustáveis (ASD), fornos, fontes de alimentação de computadores, sistemas HVDC, etc. Os dispositivos electrónicos de potência, devido à sua não-linearidade inerente, retiram potência harmónica e reactiva da alimentação. Em sistemas trifásicos, podem também causar desequilíbrios e absorver correntes de neutro excessivas. O sistema elétrico está sujeito a vários transientes, tais como afundamentos de tensão, oscilações, cintilações, etc. Este livro aborda a necessidade de melhorar a qualidade da energia, especificamente no que diz respeito à minimização das harmónicas, utilizando técnicas de IA e o MATLAB/SIMULINK como ferramenta de modelação, análise, simulação e otimização. Este trabalho destina-se a ser utilizado por investigadores e industriais. Para além disso, será especialmente relevante e útil para os estudantes de Engenharia Eletrotécnica para a realização de investigação nesta área.

Con l'avvento dei dispositivi di commutazione a semiconduttore di potenza, come tiristori, GTO (Gate Turn off thyristors), IGBT (Insulated Gate Bipolar Transistors) e molti altri dispositivi, il controllo dell'energia elettrica è diventato una realtà. Questi controllori elettronici di potenza sono ampiamente utilizzati per alimentare carichi elettrici, come azionamenti a velocità regolabile (ASD), forni, alimentatori per computer, sistemi HVDC, ecc. I dispositivi elettronici di potenza, a causa della loro intrinseca non linearità, assorbono energia armonica e reattiva dall'alimentazione. Nei sistemi trifase, possono anche causare squilibri e assorbire correnti di neutro eccessive. Il sistema di alimentazione è soggetto a vari transitori come cali di tensione, oscillazioni, sfarfallii, ecc. Questo libro affronta l'esigenza di migliorare la qualità dell'alimentazione, in particolare per quanto riguarda la minimizzazione delle armoniche, utilizzando le tecniche di intelligenza artificiale e MATLAB/SIMULINK come strumento di modellazione, analisi, simulazione e ottimizzazione. Questo lavoro è destinato ad essere utilizzato da ricercatori e industriali. Inoltre, sarà particolarmente rilevante e utile per gli studenti di ingegneria elettrica per lo svolgimento di ricerche in questo settore.

Avec l'avènement des dispositifs de commutation à semi-conducteurs de puissance, tels que les thyristors, les GTO (Gate Turn off thyristors), les IGBT (Insulated Gate Bipolar Transistors) et bien d'autres dispositifs, le contrôle de l'énergie électrique est devenu une réalité. Ces contrôleurs électroniques de puissance sont largement utilisés pour alimenter les charges électriques, telles que les variateurs de vitesse (ASD), les fours, les alimentations d'ordinateurs, les systèmes HVDC, etc. En raison de leur non-linéarité inhérente, les dispositifs électroniques de puissance tirent des harmoniques et de la puissance réactive de l'alimentation. Dans les systèmes triphasés, ils peuvent également provoquer un déséquilibre et tirer des courants neutres excessifs. Le système électrique est soumis à divers phénomènes transitoires tels que les baisses de tension, les houles, les scintillements, etc. Ce livre traite de l'amélioration de la qualité de l'énergie, en particulier en ce qui concerne la minimisation des harmoniques à l'aide de techniques d'intelligence artificielle utilisant MATLAB/SIMULINK comme outil de modélisation, d'analyse, de simulation et d'optimisation. Ce travail est destiné à être utilisé par les chercheurs et les industriels. En outre, il sera particulièrement pertinent et utile pour les étudiants en génie électrique qui souhaitent effectuer des recherches dans ce domaine.

Mit dem Aufkommen von Leistungshalbleiter-Schaltgeräten wie Thyristoren, GTOs (Gate Turn off thyristors), IGBTs (Insulated Gate Bipolar Transistors) und vielen anderen Geräten ist die Steuerung der elektrischen Leistung Realität geworden. Solche leistungselektronischen Steuerungen werden in großem Umfang eingesetzt, um elektrische Lasten mit Strom zu versorgen, z. B. drehzahlgeregelte Antriebe (ASDs), Öfen, Computernetzteile, HVDC-Systeme usw. Aufgrund ihrer inhärenten Nichtlinearität entziehen die leistungselektronischen Geräte dem Netz Oberschwingungen und Blindleistung. In Dreiphasensystemen können sie auch Ungleichgewichte verursachen und übermäßige Neutralströme ziehen. Das Stromversorgungssystem ist verschiedenen Transienten wie Spannungsabfällen, Überspannungen, Flickern usw. ausgesetzt. Dieses Buch befasst sich mit der Verbesserung der Netzqualität, insbesondere im Hinblick auf die Minimierung von Oberschwingungen mit Hilfe von KI-Techniken unter Verwendung von MATLAB/SIMULINK als Werkzeug für die Modellierung, Analyse, Simulation und Optimierung. Diese Arbeit ist für die Nutzung durch Forscher und Industrielle gedacht. Darüber hinaus ist sie besonders für Studenten der Elektrotechnik relevant und nützlich, um in diesem Bereich zu forschen.

Present study evaluates the possibility of selective leaching of manganese from complex, in a high temperature sulphuric acid dissolution process. The factors affecting the sulphuric acid leaching of the manganese complex in presence of various parameters were investigated. Experiments were carried out at temperatures ranging from 40-110 deg.C, time from 30-150 minutes and sulphuric acid concentration from 2-6%. The ore prepared is in close resemblance to pyrolusite ore. The results show that as temperature of the medium increases, the percentage recovery of manganese increases. The optimum conditions established for maximum metal extraction are: 100 deg.C temperature, 2 hours time and 5% concentrated sulphuric acid. Under these conditions, recovery of Mn was 98%. The present process may find applications of separation of manganese from iron and aluminium at high temperature during various hydrometallurgical treatment of manganese based ores. This work is aimed for utilization by researchers, industrialists¿ and traditional businesses. Apart from this it will be especially relevant and useful for the students of Metallurgy, Mining, Mechanical engineering and Chemical engineering.

The high energy demand in an industrialized world as well as in the domestic sector and pollution problem caused due to the wide spread use of fossil fuels makes it necessary to develop the renewable energy sources/fuels with lower environmental impact than the conventional ones. An alternative fuel must be technically feasible, economically competitive, environmentally acceptable and readily available. Research into finding alternative to petroleum based fuel especially in terms of biodiesel has been on the forefront. The present work reports the use of sonochemical reactor as a technique for intensification of biodiesel synthesis. Use of sonochemical reactors can favor the reaction chemistry and propagation by way of enhanced mass transfer and inter phase mixing between the phases and also can lower the requirement of the severity of the operating conditions in terms of temperature and pressure. This work is aimed for utilization by researchers, industrialists¿ and traditional businesses. Apart from this it will be especially relevant and useful for the students of Mechanical and Chemical engineering for carrying out research in this area.

Biodiesel (fatty acid methyl ester) which is derived from triglycerides by transesterification has attracted considerable attention during the past decade as a renewable, biodegradable and nontoxic fuel. Several processes for biodiesel production have been developed, among which transesterification using alkali as catalyst gives high level of conversion of triglycerides to their corresponding methyl ester in a short duration. In India, non-edible seeds like pongamia are available in abundance and these seeds can be converted to biodiesel. In the present study, biodiesel has been prepared by in-situ transesterification from pongamia seeds which have been dried and dehulled. In this method glycerol (which is obtained as a by-product in conventional method of biodiesel) is adsorbed onto the oilseeds. Hence the glycerol removal step is eliminated. In this work the feasibility is tested and is hence proven that biodiesel can be formed by this process. This work is aimed for utilization by researchers, industrialists¿ and traditional businesses. Apart from this it will be especially relevant and useful for the students of Mechanical and Chemical engineering for carrying out research.

Oleo chemicals are chemicals derived from biological oils or fats. Though the same chemicals can be derived from petroleum (petrochemicals) as is being widely followed, the natural Oleo chemicals offer a cleaner and cheaper production route than the petrochemical route. The natural route also promises a variety of diversification routes as well as valuable co-products and by-products. The hydrolysis or alcoholysis of oils or fats form the basis of the oleo chemical industry. The formation of basic oleo chemical substances like fatty acids, fatty acid methyl esters (FAME), fatty alcohols, fatty amines and glycerols are by various chemical and enzymatic reactions. The growth of oleo chemicals in the past few decades has been quite phenomenal, parallel to the rapid growth of the petrochemical industry. The oleo chemical industry is fairly well developed and its future secure because of a reliable supply of raw materials. The world¿s fats and oils output has been growing rapidly over the past few decades, far beyond the need for human nutrition. This book will be especially useful for Chemical Engineers, Chemical Technologists, Food Technologists and for Industrialists & Entrepreneurs.

Liquid-liquid extraction or solvent extraction is the separation of the components of a liquid solution by contact with another liquid solvent, which is relatively immiscible with feed solution. The liquid, which is added to the solution to bring out extraction, is known as solvent. This solvent takes up part of the solute and forms an immiscible layer with the remaining solution. The solvent layer is called extract and the other layer is called raffinate. Extraction involves the use of systems composed of at least three substances and although for the most part of the insoluble phases are chemically very different, generally three components appear at least to some extent in both phases. In this work analysis of batch extraction for different concentrations of solute and solvent with respect to time is done. It is found that % recovery of solute increases with increasing the concentration of solute and decreases with increase in the quantity of solvent. This work is aimed for utilization by researchers, industrialists¿ and traditional businesses. Apart from this it will be especially relevant and useful for the students of Chemical & Process Engineering for carrying out research.

Energy is most important for economic growth and human development. Every day, we come across food, vegetable wastes and other organic wastes that have huge potential to uplift the society in a better way, when these are transformed into useful bioenergy. To produce bioenergy from biomass one of the better options is to utilize these potential wastes to transform it into biogas. Today, the entire world is looking for different alternative fuels. Biogas is one of the good alternative fuels, energy rich and is well suited as domestic fuel, for heating purposes and power generation. The sources available for the production of biogas are fruit, vegetable wastes and agricultural residues. Biogas from such solid wastes primarily constitutes of methane, carbon dioxide and other trace gases. It is a clean fuel with a calorific value between 5000 to 5500 kcal/kg. There are two methods available for the production of biogas from organic wastes (Dry and Wet Processes). The dry processes include combustion and pyrolysis, whereas the wet processes include anaerobic digestion, gasification and fermentation. This book will be especially useful for Chemical, Mechanical & Agricultural Engineers.

Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section in solid materials. The drill bit is pressed against the work piece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the work piece, cutting off chips from the hole as it is drilled. Drilling operations are conducted on the E Glass epoxy fiber reinforced pieces with 12 mm and 8 mm diameter drills with 118 deg. and 120 deg. point angles with different cutting parameters. The cutting parameters are spindle speed ¿ 1000 rpm and 2500 rpm, Feed ¿ 0.2 mm/rev for 8 mm drill tool and 0.35 mm/rev for 12 mm drill tool. Cutting tool material is HSS. Forces are calculated using theoretical calculations. 3D modeling is done in Creo 2.0 and analysis is done in Ansys. Analysis is performed and the stresses, displacements are compared for three materials Aluminum, Titanium alloy and E Glass Epoxy. By observing the analysis results, the stresses and displacements are less for E Glass Epoxy than Aluminum alloy and Titanium. This book will be especially useful for Mechanical & Metallurgical Engineers.