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
für 69.21€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This book presents novel approaches for efficient optimization techniques based on numerical simulations for photonic devices. It presents the recent advances in the application of the adjoint variable method to photonic devices as an efficient technique for sensitivity analysis. It also presents novel approaches for formulating the design of any photonic devices as an optimization problem. These optimization problems are then solved efficiently using gradient-based optimization algorithms. This book is the first one that shows how the optimization problem can be formulated as a convex optimization problem in photonics. Convex optimization programming allows for efficient solution of the design problem using interior point method. These approaches will highly accelerate the design cycle of novel structures to meet the ever demanding requirements of the photonic devices. ····· 1036119826
····· lezzter Preis 44.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray In radio astronomical applications, it may be essential to accurately evaluate the electromagnetic scattering and power dissipation losses of nearby dielectric objects, such as radomes. However, the numerical analysis becomes a burdensome task when the dielectric becomes thin, complex shaped, and electrically large. To mitigate these problems, we propose to employ high-resolution basis functions for accurate modeling of electromagnetic scattering from dielectric objects. Application of these basis functions significantly eases the computational burden of generating the on- and off-diagonal elements of the moment matrix. This method has been hybridized with the Characteristic Basis Function Method (CBFM) and the Adaptive Cross Approximation (ACA) algorithm to reduce both the size and generation time of the moment matrix equation. Furthermore, the proposed method is not only fast and memory efficient but it also generates the accurate solution of scattering problems associated with complex-shaped, thin and electrically large objects. ····· 1036119786
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Low voltage (LV) network loss estimation and direct load control (DLC) can play an important role in the cost-efficient operation of distribution systems. In the first part of the book new power loss computation procedures for LV residential distribution networks are presented. The deterministic method is called the `Unified Loss Theory`, because it gives an estimate of the components of the power loss, and is therefore suitable for cost-benefit calculations of loss-reduction investments. A new stochastic residential load model and an identification procedure have also been elaborated. The model is suitable for accurate simulation of the stochastic variation of the time-dependent household currents (together with the harmonics). In the second part of the book a physical load model and an identification procedure for electric storage water heaters are shown. New optimization algorithms are presented to determine the schedule for DLC load groups, in order to achieve different objective functions and taking into consideration several constraints. Results show that DLC systems are very useful tools in shaping the daily load curve and in minimizig balancing energy. ····· 1036119434
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This book has been written based on PhD thesis. In this book, most fundamental dimensional analysis technique is used to develop some mathematical relationships to understand the flashover mechanism of contaminated insulator. The expression of time to flashover, flashover voltage in terms of ESDD and surface conductivity has been developed. In addition, the relationships between leakage resistance and ESDD, and ESDD and wind velocity have been developed. All mathematical models have been verified by the experiments. ····· 1036119191
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray The book gives theoretical and experimental results in the field of interferential selectors for lasers with controllable parameters of radiation, diffraction optics, digital holography, digital signal processing and error analysis in optical metrology. Ray-tracing and plane-wave expansion methods are applied to build a generalized theory of a Fizeau wedge in reflection and transmission at illumination with typical intra-cavity laser beams. The newly established wedge properties are used for laser solutions, in which it acts as a spectrally selective tunable reflector, filter and optical coupler. Based on Fresnel diffraction integral, a theory of sinusoidal phase grating is proposed as an element for phase-shifting pattern projection profilometry of large-scale objects. Design, analysis and realization of two phase-shifting holographic systems for microscopic observations and for evaluation of plane mechanical stresses are included. The book provides theoretical description and uncertainty analysis of two systems based on a Michelson interferometer: a white light source Fourier spectrometer and a system for spectral fixation of laser diode emission to an atomic absorption line. ····· 1036118899
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray All samples were prepared using conventional solid state reaction technique and were sintered at two different temperatures in air for 1 hour. Structural and surface morphology were studied by x-ray diffraction (XRD) method and high resolution optical microscopy respectively. The magnetic properties of these ferrites were characterized by frequency (1 kHz-13MHz) and temperature dependence complex permeability measurements. DC magnetizations of all samples were measured using the Superconducting Quantum Interface Device (SQUID) magnetometer. The XRD patterns of all samples have clearly indicated the formation of spinel structure. The change in lattice parameter can be explained on the basis of the ionic radii. Resonance frequency and Neél temperature decreased as Zn content increased. Possible explanations for the observed characteristics of microstructures, initial permeability, DC magnetization, and Neél temperature of the studied samples have been discussed. ····· 1036118895
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Evanescent wave absorption sensing and spectroscopy are the widely used techniques for the detection of unknown chemicals. Tapered fibres are used in evanescent wave absorption sensing applications, due to the large fraction of modal power extended into the external environment as evanescent wave. The core-mode cut-off play a major role in the evanescent field absorption based tapered fibre sensors. The core-mode cut-off can be calculated by solving the eigen value equations of a tapered fibre considering as a weakly guiding three layer optical waveguide. Single mode tapered fibre has been fabricated to make a precision sensor element suitable for chemical detection. Finally, the sensor element has been used to detect absorption peak of ethylenediamine (EDA). The results are presented in which the absorption peak at 1540nm is observed. In the last chapter a fibre loop cavity resonator has been theoretically analyzed. The resonance conditions and steady state response of fibre loop cavity resonator has been analyzed. The fibre loop cavity resonator can be used for chemical sensing applications. ····· 1036118636
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Blue jets and gigantic jets are transient luminous events in the middle atmosphere that form when conventional lightning leaders escape upward from thundercloud tops and propagate toward the lower ionosphere. Petrov and Petrova [1999] first expressed that jets could be the extension of classic lightning discharges initiated within the cloud boundaries. This dissertation demonstrates the fundamental physical similarities between the various electrical discharges known to occur in the thundercloud due to local and global charge imbalances. How charge imbalances form in the thundercloud has been first suggested by Wilson [1921], but their impact on the occurrence of blue and gigantic jets was not explored. This work shows that the accumulation of screening charges near the thundercloud top produces a charge configuration leading to the initiation of blue jets, and the effective mixing of these charges with the upper thundercloud charge to that of gigantic jets. Also, the physics of lightning and jets, and many of the small-scale features observed in jets can be interpreted in terms of streamers (needle-shaped filaments of ionization), and are further explored via numerical modeling. ····· 1036118512
für 80.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Kniga znakomit chitatelya s analiticheskimi modelyami opisaniya rasprostraneniya elektromagnitnogo polya v neodnorodnykh sredakh, a takzhe s primeneniem etikh modeley pri reshenii prakticheskikh zadach. Prednaznachena dlya studentov vsekh form obucheniya po napravleniyu podgotovki `Energetika, energeticheskoe mashinostroenie, elektrotekhnika`, stalkivayushchikhsya s neobkhodimost`yu izucheniya elektromagnitnogo polya, a takzhe dlya magistrov, aspirantov i inzhenerno-tekhnicheskikh rabotnikov elektrotekhnicheskikh spetsial`nostey. ····· 103615150
für 61.20€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray V monografii rassmatrivaetsya teoriya vosstanovleniya signalov i izobrazheniy nauchnoe napravlenie po razrabotke metodov i sredstv kompensatsii iskazheniy, vnosimykh v signal ili v izobrazhenie v protsesse ikh formirovaniya razlichnymi neodnorodnymi sredami. Izlagayutsya novye teoreticheskie rezul`taty analiza i sinteza optimal`nykh bazisov dlya predstavleniya signalov i izobrazheniy, proshedshikh turbulentnuyu sredu, reguliruyushchie algoritmy ikh optimal`nogo vosstanovleniya. Bol`shoe vnimanie udeleno sintezu veyvlet i veyvlet-paket bazisov obladayushchikh ierarkhicheskoy strukturoy vlozhennosti, predstavleniyu differentsial`nykh i integral`nykh operatorov v lokal`nykh bazisakh. Monografiya budet poleznoy dlya nauchnykh rabotnikov i aspirantov v oblasti fizicheskoy i adaptivnoy optiki, radiofiziki, kibernetiki, radiolokatsii, prikladnoy matematiki i vychislitel`noy tekhniki. Mozhet byt` poleznoy spetsialistam drugikh oblastey, svyazannykh s obrabotkoy signalov i izobrazheniy. ····· 103615124
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray V rabote dan obzor sovremennogo sostoyaniya dvukhkomponentnoy diel`kometrii (DD) sel`skokhozyaystvennykh materialov, ispol`zuemoy dlya izmereniya deystvitel`nogo i mnimogo komponentov kompleksnoy dielektricheskoy pronitsaemosti i elektroprovodnosti, i pozvolyayushchey odnovremenno opredelyat` vlazhnost` i plotnost` zernovoy massy, vlazhnost` i elektroprovodnost` pochv. Rassmotreno novoe predlozhennoe i razrabotannoe avtorom napravlenie DD, osnovannoe na ispol`zovanii avtogeneratornykh dvukhkomponentnykh diel`kometricheskikh preobrazovateley (DDP) s emkostnymi ili induktivnymi datchikami, i obespechivayushchee vysokuyu tochnost` izmereniya. Izlozheny osnovy teorii i printsipy postroeniya avtogeneratornykh DDP, rezul`taty issledovaniy i razrabotok etikh DDP s emkostnymi datchikami dlya sredstv DD zerna i pochv, voprosy beskontaktnoy DD pochv na osnove DDP s induktivnoy antennoy. Monografiya yavlyaetsya izlozheniem doktorskoy dissertatsii, zashchishchennoy v Agrofizicheskom NII (Sankt-Peterburg, Rossiya) v 2009 g., s posleduyushchimi dopolneniyami, i prednaznachena dlya razrabotchikov perspektivnykh sredstv diel`kometricheskogo kontrolya materialov, uchenykh i inzhenerov elektrofizikov, aspirantov i studentov. ····· 103614918
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Future antenna architectures especially for space applications are becoming more and more complex due to the need of Electronic Reconfigurability. This reconfigurability is needed in terms of Radiation Pattern, Bandwidth, Reliability, and Power Consumption. In this context, Electronically Tunable Reflectarrays and Frequency Selective Surfaces (FSSs) are particularly the hottest domains of RF design. The accurate analysis of electromagnetic(EM) scattering from such reconfigurable antenna structures is of great practical interest these days. However due to their large electrical size and complex cellular patterns specially when tuning elements such as RF-MEMS switches are also integrated within the array elements, conventional full-wave EM Modeling of such multiscale structures either fail or require enormous amount of computational resources to resolve prohibitively large number of unknowns. A novel and efficient modular numerical technique called Scale Changing Technique (SCT) addresses all these problems. The focus of this book is on EM modeling of passive and active (electronically steerable by RF-MEMS Switches )microstrip reflectarray using this Technique. ····· 103613500
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Ferrimagnetic bioactive glass ceramics are expected to be potential candidates for the hyperthermia treatment of cancer. When placed in a high frequency magnetic field, these materials generate heat energy by hysteresis and eddy current losses. Unlike the conventional radiotherapy where it is very difficult to treat the deep seated tumors without harming the healthy cells, magnetic hyperthermia may be quite efficient in treating the deep seated tumors locally. Tumor cells usually perish around 43 °C whereas healthy body cells remain unaffected at this temperature. Magnetic parameters of the implant material and the applied field are tailored in such a way as to give the required optimum heat energy. Such materials should have the adequate ability to bond with the tissues (bio-activity). Much work has been done on Fe3O4 containing glass ceramics for this purpose but this work is the first ever detailed study of its kind on ZnFe2O4 containing biomaterials. Bioglass ceramic materials containing zinc ferrite nanoparticles may not only be useful for the hyperthermia therapy but also effective in re-enforcing the damaged bone by forming hydroxyapatite on material-solution interface. ····· 103613401
für 35.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray La Construcción de Circuitos de Media Tensión es de vital importancia en la actualidad debido al crecimiento urbano y a la necesidad de brindar el servicio de Energía Eléctrica de Calidad en los hogares. Este libro muestra como llevar a cabo un Mantenimiento correctivo en la línea de Media Tensión derivado de un análisis de la misma, es un gran apoyo para la realización de la Electrificación Rural pero sobre todo alcanzar el objetivo principal que todas los hogares cuenten con el servicio eléctrico. ····· 103612939
für 26.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Las fuerzas entre corrientes mediadas por campos magnéticos magnificados miles de veces por la polarización de materiales ferro-magnéticos (motores) y campos eléctricos inducidos por campos magnéticos variables (generadores y transformadores) son los fenómenos físicos fundamentales subyacentes en el funcionamiento de las máquinas eléctricas que sostienen la matriz mundial de energía eléctrica. Dichos desarrollos tecnológicos se basa en el descubrimiento de fenómenos electromagnéticos realizados hacia principios del siglo XIX por los físicos Oersted, Ampere, Faraday y otros. Es sobre esta base que desde mediados del siglo XIX, físicos, ingenieros e inventores, como Jedlik, Pixi, Pacinotti, Gramme (era de la corriente continua) y Ferraris, Tesla, Dolivo-Dovrovolski (era moderna de la corriente alterna) desarrollaron una variedad de dispositivos y sistemas que potenciaron la primera fase de la Revolución Tecnológica. El portentoso desarrollo de las máquinas eléctricas durante ese período se extiende con pocos cambios hasta nuestros días y a las épocas por venir, continuando con la generación, transmisión y empleo de la energía eléctrica esencial a nuestra Civilización Tecnológica. ····· 103612585
für 32.31€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray El documento se divide en dos capítulos: En el primer capítulo se expone el método de obra civil para la construcción de un domo Geodésico El segundo capítulo expone una metodología general para el apantallamiento de dicha estructura. La metodología de protección contra el impacto directo de la descarga(Rayos) aplicada al domo geódesico como estructura natural, es la de mayor interés en este documento. ····· 103612212· 1 ·· 2 ·· 3 ·· 4 ·· 5 ·· 6 ·· 7 ·· 8 ·· 9 ·
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