Готові списки джерел за темами / Transformers efficients

Добірка наукової літератури з теми "Transformers efficients"

Автор: Grafiati

Опубліковано: 10 травня 2022

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Статті в журналах з теми "Transformers efficients":

Dai, Jing, and Zhi Hua Li. "Analysis of the Energy Efficiency Grades Detection for Power Transformers." Advanced Materials Research 328-330 (September 2011): 1003–7. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1003.

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There is a lot of power loss in the power transmission, and the loss comes from power transformers contribute very much to this. So the implement of energy efficiency grade for power transformers has great significance to the development of power transformer, which can wash out the high energy-consuming transformer, decrease the power loss, and increase the efficiency of power transmission. The energy consumption of transformer consists of no load loss and load loss. In this test, I analyze the experiments for no load loss and load loss with the “Minimum allowable values of energy efficiency and energy efficiency grades for power transformers”, ascertaining the transformer’s efficiency grade.

Баширов, М., Mussa Bashirov, Азат Хисматуллин, Azat Hismatullin, И. Прахов, and I. Prahov. "Increasing of Power Oil-Filled Transformers’ Operation Reliability and Safety." Safety in Technosphere 7, no. 2 (January 23, 2019): 15–21. http://dx.doi.org/10.12737/article_5c35cc6e2354f7.79418159.

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This paper is devoted to the currently urgent problem — increasing reliability and safety for power oil transformers’ operation with considerable long and short overloads through cooling systems’ efficiency upgrading, allowing increase the power oil transformers’ operation safety, engine life, reliability and economical efficiency. Statistical data on fault causes for transformers of different voltage classes and lifecycles have been given. Based on the study of statistical data it has been established that one of the main causes for transformers faults was the inefficiency of oil cooling systems during the summer period of operation and with considerable long and short overloads. For improvement of efficiency of power oil transformers’ cooling system the agitation of cooling oil by circulating sulfur hexafluoride (SF6) and subsequent sulfur hexafluoride cooling with a thermoelectric cooler is proposed. The system of sulfur hexafluoride circulation and cooling switches on automatically at considerable long and short overloads. The design and operation of the proposed cooling system for oil transformers have been considered. A series of laboratory experiments for transformer oil cooling in a power transformer’s tank without and with a compressor has been carried out. Graphs of temperature-time relationship at natural cooling and when using agitation have been presented. The coefficients of transformer oil’s thermal diffusivity and heat transfer at various distances from heating element have been experimentally defined. The mathematical problem of a heat flux distribution in a rectangular parallelepiped has been considered, a solution for thermal conductivity equation in the power transformer’s tank, which is a rectangular parallelepiped, has been presented. A laboratory setup design has been described in detail. Brands of used thermocouples, compressor and analog-digital converter have been presented. Use of the upgraded cooling system will allow increase the transformers operation safety and reliability.

Orosz, Tamás, and István Vajda. "Design Optimization with Geometric Programming for Core Type Large Power Transformers." Electrical, Control and Communication Engineering 6, no. 1 (October 23, 2014): 13–18. http://dx.doi.org/10.2478/ecce-2014-0012.

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Abstract A good transformer design satisfies certain functions and requirements. We can satisfy these requirements by various designs. The aim of the manufacturers is to find the most economic choice within the limitations imposed by the constraint functions, which are the combination of the design parameters resulting in the lowest cost unit. One of the earliest application of the Geometric Programming [GP] is the optimization of power transformers. The GP formalism has two main advantages. First the formalism guarantees that the obtained solution is the global minimum. Second the new solution methods can solve even large-scale GPs extremely efficiently and reliably. The design optimization program seeks a minimum capitalized cost solution by optimally setting the transformer's geometrical and electrical parameters. The transformer's capitalized cost chosen for object function, because it takes into consideration the manufacturing and the operational costs. This paper considers the optimization for three winding, three phase, core-form power transformers. This paper presents the implemented transformer cost optimization model and the optimization results.

Kim, Jinwook, Do-Hyeon Kim, Jieun Kim, and Young-Jin Park. "Wireless Power Transfer between Two Self-Resonant Coils over Medium Distance Supporting Optimal Impedance Matching Using Ferrite Core Transformers." Energies 14, no. 24 (December 17, 2021): 8540. http://dx.doi.org/10.3390/en14248540.

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An efficient wireless power transfer (WPT) system is proposed using two self-resonant coils with a high-quality factor (Q-factor) over medium distance via an adaptive impedance matching network using ferrite core transformers. An equivalent circuit of the proposed WPT system is presented, and the system is analyzed based on circuit theory. The design and characterization methods for the transformer are also provided. Using the equivalent circuit, the appropriate relation between turn ratio and optimal impedance matching conditions for maximum power transfer efficiency is derived. The optimal impedance matching conditions for maximum power transfer efficiency according to distance are satisfied simply by changing the turn ratio of the transformers. The proposed WPT system maintains effective power transfer efficiency with little Q-factor degradation because of the ferrite core transformer. The proposed system is verified through experiments at 257 kHz. Two WPT systems with coupling efficiencies higher than 50% at 1 m are made. One uses transformers at both Tx and Rx; the other uses a transformer at Tx only while a low-loss coupling coil is applied at Rx. Using the system with transformers at both Tx and Rx, a wireless power transfer of 100 watts (100-watt light bulb) is achieved.

Kefalas, Themistoklis D., and Antonios Kladas. "Reduction of Power Grid Losses by Using Energy Efficient Distribution Transformers." Materials Science Forum 721 (June 2012): 269–74. http://dx.doi.org/10.4028/www.scientific.net/msf.721.269.

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The importance of distribution transformer no-load loss on the operation of modern electrical grids is often underestimated. Internationally, distribution transformer no-load loss constitutes nearly 25% of the transmission and distribution losses of electrical grids. The losses in European Union distribution transformers are estimated at about 33 TWh/year whereas, reactive power and harmonic losses add a further 5 TWh/year. In the Greek electrical grid the no-load losses of 140,000 distribution transformers are estimated at about 490 GWh/year. This paper has two goals the first one is to illustrate the significance of distribution transformer no-load loss in periods of high electric energy cost and the second goal is the presentation of a novel numerical methodology for wound core transformers no-load loss analysis, enabling to determine the economically and technically optimum transformer for every use.

Manisha, Kulraj Kaur, Naveen Kumar Sharma, Jashandeep Singh, and Deepika Bhalla. "Performance Assessment of IEEE/IEC Method and Duval Triangle technique for Transformer Incipient Fault Diagnosis." IOP Conference Series: Materials Science and Engineering 1228, no. 1 (March 1, 2022): 012027. http://dx.doi.org/10.1088/1757-899x/1228/1/012027.

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Abstract Power transformers are among the most important equipment in a power system. The assessment of the transformer’s condition which is connected to a system is needed to avoid disastrous failures and the subsequent power outages. Although transformers are highly dependable and efficient, but are always under the influence of thermal, electrical stresses which are caused due to the deterioration of transformer insulation. Internal faults in a transformer can be classified as incipient faults and internal short circuit faults. The former type of faults develops over an extended period of time and lead to the degradation of insulation. Incipient faults are generally the result of deterioration of the dielectric strength of transformer mineral oil due to hydrolysis, pyrolysis, and oxidation, which result in the formation of gases that are collected in the gap between the oil and tank and partially get dissolved in it. If incipient conditions are not corrected timely, they may finally lead to collapse of the system where such a transformer is installed. Dissolved Gas Analysis (DGA) methods are extensively accepted by utilities for detection of developing faults. In this work, the brief study of two of the prevalent DGA methods for identification of incipient faults has been carried out. The methods that have been studied are IEEE/IEC Ratio Method and Duval’s Triangle Method. The published DGA data where the actual fault is known is used for identification of the incipient faults and the results have been compared.

DeCristofaro, Nicholas. "Links of Science & Technology." MRS Bulletin 23, no. 5 (May 1998): 50–56. http://dx.doi.org/10.1557/s0883769400030451.

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On April 13, 1982, the Duke Power Company energized an experimental pad-mount distribution transformer in Hickory, North Carolina. The transformer, manufactured by General Electric, provided electric power to a local residence. That same month, the Georgia Power Company installed a similar transformer, made by Westinghouse Electric, atop a utility pole in Athens, Georgia. It supplied electricity for the exterior lights at the Westinghouse Newton Bridge Road plant. These devices shown in Figure 1 were unique among the nearly 40 million distribution transformers in service in the United States because their magnetic cores were made from an Fe–B–Si amorphous-metal alloy. This new material, produced by Allied-Signal (formerly Allied Chemical), was capable of magnetizing more efficiently than any electrical steel. By replacing grain-oriented silicon steel in the transformer cores, the amorphous metal reduced the core losses of the transformers by 75%.Although distribution transformers are relatively efficient devices, often operating at efficiencies as high as 99% at full load, they lose a significant amount of energy in their use. Because of the number of units in service, coupled with the fact that the core material is continuously magnetized and demagnetized at line frequency, transformers account for the largest portion of the energy losses on electric power distribution systems. It is estimated that over 50 × 109 kWh are dissipated annually in the United States in the form of distribution transformer core losses. At today's average electricity generating cost of $0.035/kWh, that energy is worth over $1,500 million.

Hanin, Yu I., O. V. Rodionova, A. P. Panchishkin, M. A. Zaichkina, and Ya E. Shakhbazova. "On the efficiency of power transformers with «star-zig-zag with zero» winding connection scheme in rural electricity networks supplying household consumers." Journal of Physics: Conference Series 2060, no. 1 (October 1, 2021): 012004. http://dx.doi.org/10.1088/1742-6596/2060/1/012004.

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Abstract The dependencies of the loss coefficient on the value of reverse- and zero-sequence current unbalance coefficients are obtained, allowing estimating the energy efficiency of power transformers operation at different unbalance characteristics. The electricity losses were calculated from these dependencies and from data obtained from instrumental measurements at rural substations supplying household consumers. It was obtained that the power transformer with «the star-zigzag with zero» scheme is 6 times more energy efficient than the power transformer with «the star–star with zero» scheme. However, with small values of the currents asymmetry (for five cases studied), the power transformer with «the star-zigzag with zero» scheme has overestimated power losses.

Gilfanov, K. H., N. Tien, R. N. Gaynullin, and I. Hallyyev. "Energy efficient heat supply system for electric power facilities." E3S Web of Conferences 124 (2019): 01011. http://dx.doi.org/10.1051/e3sconf/201912401011.

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The aim of the work is to confirm the possibility of creating an energy-saving heat supply system for power facilities by using computer modelling, analysis of the potential use of heat losses of electromagnetic energy in magnetic circuits and windings of transformers of substations, as well as the development of schemes for heat recovery losses for heat supply of power facilities. Computer simulation of electromagnetic and thermophysical processes in the power oil-filled transformer is carried out. Energy losses in windings, hysteresis and eddy currents in the magnetic circuit, as well as temperature and heat flux fields in the longitudinal and transverse sections of the oil-filled power transformer in idle and short-circuit modes were determined. The transformer performance in terms of heat recovery losses was evaluated. The possible volumes of heat extraction for heat supply depending on the power of the transformer are determined. The automated oil-water system of heat recovery of the transformer for heating of electric power facilities is proposed. The significance of the obtained results for the construction industry is to confirm the possibility of creating an energy-saving heat supply system for electric power facilities while maintaining the operational characteristics of the transformer based on computer modelling; the significant potential of using the heat loss of power transformers of substations is shown, an automated heat supply system for electric power facilities is proposed.

Hu, Xiao Ping, Bin Chen, Ye Long Zhong, and Jun Ming Xu. "Design of UHF Thin Film Transformer and Research of its S-Parameter Performance." Advanced Materials Research 482-484 (February 2012): 1542–46. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1542.

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A novel spiral stacked thin film transformer was designed based on Si IC technology in this paper. And also, the stacked air core and ferrite core thin film transformers with different turns ratio were prepareed. Then, the S-parameter performance of these two kinds of transformers were measured. The measurement results show that the magnetic core thin film transformer has a better electronic transmission performance. It obtains maximum transmission efficiency 93.7% at the frequency range from 10MHz to 20GHz, and the air core transformer obtains maximum 89% at the same frequency range. Many testings show that ferrite core thin film transformer with turns ratio 1:1 can obtain the transmission efficiency over 60% at the frequency range from 2GHz to 16GHz.

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Дисертації з теми "Transformers efficients":

Condevaux, Charles. "Méthodes d'apprentissage automatique pour l'analyse de corpus jurisprudentiels." Thesis, Nîmes, 2021. http://www.theses.fr/2021NIME0008.

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Les décisions de justice contiennent des informations déterministes (dont le contenu est récurrent d'une décision à une autre) et des informations aléatoires (à caractère probabiliste). Ces deux types d'information rentrent en ligne de compte dans la prise de décision d’un juge. Les premières peuvent la conforter dans la mesure où l’information déterministe est un élément récurrent et bien connu de la jurisprudence (i.e. des résultats d’affaires passées). Les secondes, apparentées à des caractères rares ou exceptionnels, peuvent rendre la prise de décision difficile et peuvent elles-mêmes modifier la jurisprudence. L’objet de cette thèse est de proposer un modèle d’apprentissage profond mettant en évidence ces deux types d’information afin d’en étudier leur impact (contribution) dans la prise de décision d’un juge. L'objectif est d’analyser des décisions similaires, de mettre en évidence les informations aléatoires et déterministes dans un corpus de décisions et de quantifier leur importance dans le processus de jugement
Judicial decisions contain deterministic information (whose content is recurrent from one decision to another) and random information (probabilistic). Both types of information come into play in a judge's decision-making process. The former can reinforce the decision insofar as deterministic information is a recurring and well-known element of case law (ie past business results). The latter, which are related to rare or exceptional characters, can make decision-making difficult, since they can modify the case law. The purpose of this thesis is to propose a deep learning model that would highlight these two types of information and study their impact (contribution) in the judge’s decision-making process. The objective is to analyze similar decisions in order to highlight random and deterministic information in a body of decisions and quantify their importance in the judgment process

TANTEH, DERICK NJOMBOG, SHAFIQ YOUSEF AL-LIDDAWI, and DANIEL SSEKASIKO. "PROPERTIES OF TRANSFORMER OIL THAT AFFECT EFFICIENCY." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2664.

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Abstract. Transformer explosions caused by dielectric failure account for over 50% of the disasters. The aim of this thesis is to examine, compare and outline the differences, in function, as dielectric insulators, vegetables oil has, with respect to the mineral oil used in high-power transformers. We will first consider the vegetable oil which has less dielectric capabilities than the mineral oil used in power transformers. Later in the experiments, we will focus mainly to examine the breakdown voltage property, as we try to alter some properties of the respective oils used. Considering the fact that vegetable oil has low viscosity, with its chemical compounds constituting less molecular masses compared to mineral oil, we endorse, from our experimental findings, that mineral oil is indeed worthy and reasonable to be used as a dielectric in high power transformers. In this write-up, we have considered eleven transformer oil properties. In the experiment proper, we considered only the acidity, whose concentration in the transformer oil increases with aging if the transformer, moisture, and a ‘suitable’ impurity like NaOH(aq). At first glance, one would be tempted to think, as we were, that since the increase in acid content of the oil deteriorates its dielectric performance, an increase in alkaline content of the transformer oil, would increase its dielectric ability; reversing the acid effect. But as we see in the results from our experiments, this is false. We think that the visible degradation of the insulating property of the oil, with the introduction of NaOH(aq), is because it acts as an impurity to suitable dielectric function. From the experiments, the heating procedures resulted in the production of toxic gases. This indicated the actual loss of chemical structure and significant breakage of chemical bonds. The resulting chemical composition of the oil does not produce the same dielectric properties as the initial oil sample. Also, here has been considerable inconsistency in the addition of NaOH(aq) or HCl(aq) to both oils. We only added HCl(aq), before every measurement, in two of the experiments. The other experiments were either with moisture, or a single addition of 2cm3 of either HCl(aq) or NaOH(aq) before heating; after which several measurements were taken, at specific intervals, as the mixture cools. We did so, in the latter, in which we had only one addition of a 2cm3 chemical, because in real life, given the short time frame of the experiment, the total amount of acid in the oil has a negligible change. So, in a functioning heated transformer, within a short time frame, there is actually deterioration in oil insulation properties

Liu, Du. "Efficient Video Coding with Motion-Compensated Orthogonal Transforms." Thesis, KTH, Ljud- och bildbehandling, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91858.

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Well-known standard hybrid coding techniques utilize the concept of motioncompensated predictive coding in a closed-loop. The resulting coding dependencies are a major challenge for packet-based networks like the Internet. On the other hand, subband coding techniques avoid the dependencies of predictive coding and are able to generate video streams that better match packet-based networks. An interesting class for subband coding is the socalled motion-compensated orthogonal transform. It generates orthogonal subband coefficients for arbitrary underlying motion fields. In this project, a theoretical lossless signal model based on Gaussian distribution is proposed. It is possible to obtain the optimal rate allocation from this model. Additionally, a rate-distortion efficient video coding scheme is developed that takes advantage of motion-compensated orthogonal transforms. The scheme combines multiple types of motion-compensated orthogonal transforms, variable block size, and half-pel accurate motion compensation. The experimental results show that this scheme outperforms individual motion-compensated orthogonal transforms.

Pasini, Damiano. "A new theory for modelling the mass efficiency of material, shape and form." Thesis, University of Bristol, 2002. http://hdl.handle.net/1983/a88a3e49-72b2-4605-974b-1cc589649c82.

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Hamood, Monir Taha. "Development of efficient algorithms for fast computation of discrete transforms." Thesis, University of Newcastle Upon Tyne, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576637.

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Transforms are widely used in diverse applications of science, engineering and technology. In particular, the field of digital signal processing has grown rapidly and achieved their performance through the development of fast algorithms for computing discrete transforms. This thesis focuses on the computation, generalisation and applications of four commonly used transforms, namely the new Mersenne number transform (NMNT), the discrete Fourier transform (DFT), the discreet Hartley transform (DHT), and the Walsh-Hadamard transform (WHT). As a result, several new algorithms are developed and two number theoretic transforms (NTTs) are introduced. The NMNT has been proved to be an important transform as it is utilised for error- free calculation of convolution and correlation with long transform lengths. In this thesis, new algorithms for the fast calculation of the NMNT based on the Rader- Brenner approach are developed, where the transform's structure is enhanced and the lowest multiplicative complexity among all existing NMNT algorithms is achieved. Two new NTTs defined modulo the Mersenne primes, named odd NMNT (ONMNT) and odd-squared NMNT (02NMNT), are introduced for incorporation into generalised NMNT (GNMNT) transforms which are categorised by type, with detailed instructions regarding their derivations. Development of their radix-2 and split radix algorithms, along with an example of the calculation of different types of convolutions, shows that these new transforms are suitable for wide range of applications. In order to take advantage of the simplest structural complexity provided by the radix-2 algorithm and the reduced computational complexity offered by a higher radix algorithm, a technique suitable for combining these two algorithms has been proposed, producing new fast Fourier transform (FFT) algorithms known as radix-Z' FFTs. In this thesis, a general decomposition method for developing these algorithms is introduced based on the decimation in time approach, applicable to one and multidimensional FFTs. The DHT has been proposed as an efficient alternative to the DFT for real data applications, because it is a real-to-real transform and possesses similar properties as the DFT. Based on the relationship between the DHT and complex-valued OFT, a unified 'FFT to FHT transition approach' is presented, providing a translation of FFT algorithms into their fast Hartley transform (FHT) counterparts. Using this approach, many new FHT algorithms in one and multidimensional cases are obtained. Finally, the combination of the WHT with the DFT has been proved to be a good candidate for improving the performances of orthogonal frequency division multiplexing (OFDM) systems. Therefore, part of this thesis deals with the Walsh- Hadamard-Fourier transform (WFT) that combines these transforms into a single orthogonal transform. Development of fast WFT (FWFT) algorithms has shown a significant reduction in the number of arithmetic operations and computer run times.

Pang, Erwin. "Parameter estimation and efficient implementation of affine transforms for digital images." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28850.pdf.

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Al-Azawi, Saad Mohammed Saleh. "Efficient architectures for multidimensional discrete transforms in image and video processing applications." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2131.

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This thesis introduces new image compression algorithms, their related architectures and data transforms architectures. The proposed architectures consider the current hardware architectures concerns, such as power consumption, hardware usage, memory requirement, computation time and output accuracy. These concerns and problems are crucial in multidimensional image and video processing applications. This research is divided into three image and video processing related topics: low complexity non-transform-based image compression algorithms and their architectures, architectures for multidimensional Discrete Cosine Transform (DCT); and architectures for multidimensional Discrete Wavelet Transform (DWT). The proposed architectures are parameterised in terms of wordlength, pipelining and input data size. Taking such parameterisation into account, efficient non-transform based and low complexity image compression algorithms for better rate distortion performance are proposed. The proposed algorithms are based on the Adaptive Quantisation Coding (AQC) algorithm, and they achieve a controllable output bit rate and accuracy by considering the intensity variation of each image block. Their high speed, low hardware usage and low power consumption architectures are also introduced and implemented on Xilinx devices. Furthermore, efficient hardware architectures for multidimensional DCT based on the 1-D DCT Radix-2 and 3-D DCT Vector Radix (3-D DCT VR) fast algorithms have been proposed. These architectures attain fast and accurate 3-D DCT computation and provide high processing speed and power consumption reduction. In addition, this research also introduces two low hardware usage 3-D DCT VR architectures. Such architectures perform the computation of butterfly and post addition stages without using block memory for data transposition, which in turn reduces the hardware usage and improves the performance of the proposed architectures. Moreover, parallel and multiplierless lifting-based architectures for the 1-D, 2-D and 3-D Cohen-Daubechies-Feauveau 9/7 (CDF 9/7) DWT computation are also introduced. The presented architectures represent an efficient multiplierless and low memory requirement CDF 9/7 DWT computation scheme using the separable approach. Furthermore, the proposed architectures have been implemented and tested using Xilinx FPGA devices. The evaluation results have revealed that a speed of up to 315 MHz can be achieved in the proposed AQC-based architectures. Further, a speed of up to 330 MHz and low utilisation rate of 722 to 1235 can be achieved in the proposed 3-D DCT VR architectures. In addition, in the proposed 3-D DWT architecture, the computation time of 3-D DWT for data size of 144×176×8-pixel is less than 0.33 ms. Also, a power consumption of 102 mW at 50 MHz clock frequency using 256×256-pixel frame size is achieved. The accuracy tests for all architectures have revealed that a PSNR of infinite can be attained.

Ngounda, Edgard. "Efficient numerical methods based on integral transforms to solve option pricing problems." Thesis, University of the Western Cape, 2012. http://hdl.handle.net/11394/4223.

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Philosophiae Doctor - PhD
In this thesis, we design and implement a class of numerical methods (based on integral transforms) to solve PDEs for pricing a variety of financial derivatives. Our approach is based on spectral discretization of the spatial (asset) derivatives and the use of inverse Laplace transforms to solve the resulting problem in time. The conventional spectral methods are further modified by using piecewise high order rational interpolants on the Chebyshev mesh within each sub-domain with the boundary domain placed at the strike price where the discontinuity is located. The resulting system is then solved by applying Laplace transform method through deformation of a contour integral. Firstly, we use this approach to price plain vanilla options and then extend it to price options described by a jump-diffusion model, barrier options and the Heston’s volatility model. To approximate the integral part in the jump-diffusion model, we use the Gauss-Legendre quadrature method. Finally, we carry out extensive numerical simulations to value these options and associated Greeks (the measures of sensitivity). The results presented in this thesis demonstrate the spectral accuracy and efficiency of our approach, which can therefore be considered as an alternative approach to price these class of options.

Islas, Michael. "EFFICIENCY IMPROVEMENT TECHNIQUES FOR HIGH VOLTAGE CAPACITOR CHARGING METHODS." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2969.

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The goal of this thesis is to design and fabricate a DC-to-DC converter for use in high-voltage capacitor charging applications. The primary objectives include increasing the efficiency and reducing the cost of traditional methods used for this application. Traditional methods were not designed specifically for high-voltage capacitor charging and were thus very primitive and exhibited lower efficiency. Prior methods made use of a high voltage power supply and a current limiting resistor or control scheme. The power supply would often only operate efficiently at a single voltage value and would thus function poorly over a range used in charging a capacitor. The resistor would also dissipate a fair amount of power, also limiting efficiency. This design makes use of a traditional flyback topology utilizing a controller developed specifically for this application, centering the design approach on the LT3750. Hence, taking full advantage of the efficiency improving control scheme it provides. Additionally, through the use of advanced techniques to eliminate noise and power losses, the efficiency may be significantly improved. A detailed theoretical analysis of the charger is also presented. The analysis will then be applied to optimization techniques to select ideal component values to meet specific design specifications. In this research, a specifically designed and developed prototype will be used to experimentally verify the theoretical work and optimization techniques.
M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE

Toivonen, T. (Tuukka). "Efficient methods for video coding and processing." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514286957.

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Abstract This thesis presents several novel improvements to video coding algorithms, including block-based motion estimation, quantization selection, and video filtering. Most of the presented improvements are fully compatible with the standards in general use, including MPEG-1, MPEG-2, MPEG-4, H.261, H.263, and H.264. For quantization selection, new methods are developed based on the rate-distortion theory. The first method obtains locally optimal frame-level quantization parameter considering frame-wise dependencies. The method is applicable to generic optimization problems, including also motion estimation. The second method, aimed at real-time performance, heuristically modulates the quantization parameter in sequential frames improving significantly the rate-distortion performance. It also utilizes multiple reference frames when available, as in H.264. Finally, coding efficiency is improved by introducing a new matching criterion for motion estimation which can estimate the bit rate after transform coding more accurately, leading to better motion vectors. For fast motion estimation, several improvements on prior methods are proposed. First, fast matching, based on filtering and subsampling, is combined with a state-of-the-art search strategy to create a very quick and high-quality motion estimation method. The successive elimination algorithm (SEA) is also applied to the method and its performance is improved by deriving a new tighter lower bound and increasing it with a small constant, which eliminates a larger part of the candidate motion vectors, degrading quality only insignificantly. As an alternative, the multilevel SEA (MSEA) is applied to the H.264-compatible motion estimation utilizing efficiently the various available block sizes in the standard. Then, a new method is developed for refining the motion vector obtained from any fast and suboptimal motion estimation method. The resulting algorithm can be easily adjusted to have the desired tradeoff between computational complexity and rate-distortion performance. For refining integer motion vectors into half-pixel resolution, a new very quick but accurate method is developed based on the mathematical properties of bilinear interpolation. Finally, novel number theoretic transforms are developed which are best suited for two-dimensional image filtering, including image restoration and enhancement, but methods are developed with a view to the use of the transforms also for very reliable motion estimation.

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Книги з теми "Transformers efficients":

Kennedy, Barry W. Energy efficient transformers. New York: McGraw-Hill, 1997.

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Nadel, Steven. Powerful priorities: Updating energy efficiency standards for residential furnaces, commercial air conditioners, and distribution transformers. Washington, DC: American Council for an Energy-Efficient Economy, 2004.

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Pang, Erwin. Parameter estimation and efficient implementation of affine transforms for digital images. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.

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s, Carmen Page. La era de la productividad: Co mo transformar las economi as desde sus cimientos. Edited by Inter-American Development Bank. Washington, D.C: Banco Interamericano de Desarrollo, 2010.

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M, Vangel, Petersons Oskars, and National Institute of Standards and Technology (U.S.), eds. An analysis of efficiency testing under the Energy Policy and Conservation Act: A case study with application to distribution transformers. Gaithersburg, MD: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1999.

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Giovannini, Alberto. Information in the Financial System. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198815815.003.0020.

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The financial system is one of the primary users of information technology, which in recent decades has experienced phenomenal progress. This chapter discusses how information and communication technology has changed the financial system, and what policy challenges arise from the interactions of information technology progress and financial innovation. I focus on the asset management and banking industries. In the case of asset management, progress in information technology has partially transformed the industry, and potentially made it more efficient. In the case of banking, the industry has been changed profoundly, has grown significantly, but at the same time it has become more fragile. The chapter discusses the implications of these phenomena for policymaking.

Maisel, L. Sandy. 2. A brief history of American political parties. Oxford University Press, 2016. http://dx.doi.org/10.1093/actrade/9780190458164.003.0002.

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‘A brief history of American political parties’ traces the development of US politics from the initial emergence of parties as the Founders differed on policies they believed served the nation's interests. The modern Democratic Party has transformed from its early manifestation as the Democratic-Republican Party, while the Republican Party was formed as a result of the division over slavery and eclipsed earlier parties, including the National Republicans and Whigs, as the major alternative to the Democrats. Despite party changes, the election process remains the same; it is still about organizing, understanding the rules and the voters, and knowing how to appeal to the voters most efficiently under the rules.

Anderson, James A. After Digital. Oxford University Press, 2018. http://dx.doi.org/10.1093/acprof:oso/9780199357789.001.0001.

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We are surrounded by digital computers. They do many things well that humans do not and have transformed our lives. But all computers are not the same. Although digital computers dominate today’s world, alternative ways to “compute” might be better and more efficient than digital computation when mechanically performing those tasks, important to humans, that we think of as “cognition.” Cognition, after all, was originally developed to work with our own specific biological hardware. Digital computers require elaborate detailed instructions to work; they are flexible but not simple. Analog computers are designed to do specific tasks. They can be simple but not flexible. Hardware matters. The book discusses two classic kinds of computer, digital and analog, and gives examples of their history, functions, and limitations. The author suggest that when brain “hardware,” with its associated brain “software” work together, it could form a computer architecture that would be useful for the efficient performance of cognitive tasks. This book discusses the essentials of brain hardware—in particular, the cerebral cortex, where cognition lives—and how cortical structure can influence the form taken by the computational operations underlying cognition. Topics include association, understanding complex systems through analogy, formation of abstractions, and the biology of number and its use in arithmetic and mathematics. The author introduces novel “brain-like” control mechanisms: active associative search and traveling waves. There is discussion on computing across scales of organization from single neurons to brain regions containing millions of neurons.

Newman, Stuart A. Toward a Nonidealist Evolutionary Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199377176.003.0006.

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The received model of evolution sees all inherited features resulting from deterministic networks of interacting genes, implying that living systems are reducible to information in genetic programs. The model requires these programs and their associated phenotypes to have evolved by an isotropic search process occurring in gradual steps with no preferred morphological outcomes. The alternative is to recognize that clusters and aggregates of cells, the raw material of evolution, constitute middle-scale material systems. This implies the necessity of bringing the modern physics of mesoscale matter into the explanatory framework for the evolution of development. The relevant, often nonlinear, physical processes were mobilized at the inception of the phyla when their signature morphological outcomes first appeared and remain as efficient causes, albeit transformed, in present-day embryos. This physicogenetic perspective reengages with concepts of saltation, orthogenesis, and environment-induced plasticity long excluded from evolutionary theory.

Mast, Christof, Friederike Möller, Moritz Kreysing, Severin Schink, Benedikt Obermayer, Ulrich Gerland, and Dieter Braun. Toward living nanomachines. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0039.

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How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

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Частини книг з теми "Transformers efficients":

Targosz, Roman, Stefan Fassbinder, and Angelo Baggini. "Power Transformers." In Electrical Energy Efficiency, 21–69. Chichester, UK: John Wiley & Sons, Ltd, 2012. http://dx.doi.org/10.1002/9781119990048.ch3.

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Krarti, Moncef. "Electrical Transformers." In Energy-Efficient Electrical Systems for Buildings, 51–68. Boca Raton: Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, [2017]: CRC Press, 2017. http://dx.doi.org/10.1201/9781315372297-3.

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Rietveld, Gert, Ernest Houtzager, Dennis Hoogenboom, and Gu Ye. "Reliable Power Transformer Efficiency Tests." In Lecture Notes in Electrical Engineering, 113–25. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5600-5_10.

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Mensa-Bonsu, Benjamin, Tao Cai, Tresor Y. Koffi, and Dejiao Niu. "The Novel Efficient Transformer for NLP." In Knowledge Science, Engineering and Management, 139–51. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-82147-0_12.

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Chen, Dong, Gang Hua, Fang Wen, and Jian Sun. "Supervised Transformer Network for Efficient Face Detection." In Computer Vision – ECCV 2016, 122–38. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-46454-1_8.

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Pardo, Pere, Enrique Sarrión-Morillo, Fernando Soler-Toscano, and Fernando R. Velázquez-Quesada. "Efficient Program Transformers for Translating LCC to PDL." In Logics in Artificial Intelligence, 253–66. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11558-0_18.

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Mathew, Leeja, and V. R. Bindu. "Efficient Classification Techniques in Sentiment Analysis Using Transformers." In Advances in Intelligent Systems and Computing, 849–62. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2594-7_69.

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Martis, Jan. "Push–Pull Converter Transformer Maximum Efficiency Optimization." In Advances in Intelligent Systems and Computing, 211–18. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-65960-2_27.

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Janić, Žarko, Anthony Walsh, Adesh Singh, and Yordan Botev. "Power Transformer Efficiency—Survey Results and Assessment of Efficiency Implementation." In Lecture Notes in Electrical Engineering, 103–12. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5600-5_9.

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Long, Chao, Yanmin Zhu, Haobing Liu, and Jiadi Yu. "Efficient Feature Interactions Learning with Gated Attention Transformer." In Web Information Systems Engineering – WISE 2021, 3–17. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-91560-5_1.

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Тези доповідей конференцій з теми "Transformers efficients":

Lee, Sangyoon, and Perry Y. Li. "Passivity Based Backstepping Control for Trajectory Tracking Using a Hydraulic Transformer." In ASME/BATH 2015 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/fpmc2015-9618.

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Throttling loss is a major contributor to the low system efficiency in hydraulic systems. Hydraulic transformers can potentially be an energy efficient, throttle-less control approach for multi-actuators systems powered by a common pressure rail (CPR). The transformer transforms the input CPR pressure to the desired pressure of the actuator instead of throttling it. Regenerative energy can also be captured. For transformers to be useful, they must also have good control performance. This paper presents a a passivity based trajectory tracking controller for a hydraulic actuator driven by a transformer consisting of two mechanically coupled variable displacement pump/motors. In addition to controlling the motion of the actuator, the transformer speed can also be regulated at the most efficient operating speed. The nonlinear controller is designed using a Lyapunov function that is based upon a recently discovered natural energy storage function for hydraulic actuators. Experimental results validate the efficacy of this controller.

Brady, Ryan, Sebastien Muller, Margareta Petrovan-Boiarciuc, Guillaume Perigaud, and Benjamin Landis. "Prevention of Transformer Tank Explosion: Part 3—Design of Efficient Protections Using Numerical Simulations." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77413.

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Electricity markets are very competitive and in order to limit costs, companies often reduce their investments by using aging equipment and by overloading their transformers. For these reasons, oil-filled transformer explosions are becoming more and more frequent. They are caused by electrical arcs occurring in transformer tanks. Within milliseconds, arcs vaporize the surrounding oil and the generated gas is pressurized because the liquid inertia prevents its expansion. The pressure difference between the gas bubble and the surrounding liquid oil generates a dynamic pressure peak, which propagates and interacts with the tank. Then, the reflections generate pressure waves that build up the static pressure, leading to tank rupture since tanks are not designed to withstand such levels of static pressure. This results in dangerous explosions, expensive damages and possible environmental pollution. Despite all these risks, and contrarily to usual pressure vessels, no specific standard has been set to protect sealed transformer tanks subjected to large dynamic overpressures. To limit the consequences of an explosion, protective walls surrounding transformers can contain the explosion while sprinklers may extinguish the induced fire. In order to extend this chain of protections to the transformer itself, a strategy to avoid transformer tank rupture was developed and presented at the previous PVP08 Conference (PVP2008-61526 - Prevention of Transformer Tank Explosion: Part 1). The concept of this strategy is based on the direct mechanical response of a depressurization set to the inner dynamic pressure induced by electrical faults. In the same paper, the efficiency of this depressurization strategy was experimentally shown: if the oil evacuation through the depressurization set is activated within milliseconds by the first dynamic pressure peak before static pressure increases, the explosion can be prevented. The use of these protections eliminates the need to design transformer tanks as pressure vessels, which by application of the ASME standard would require a significant increase of the the shell thickness. Complementarily, a compressible two-phase flow numerical simulation tool based on a 3D finite volume method was developed to study transformer explosions and possible strategies for their prevention. Its theoretical bases were detailed in the PVP08 ASME Conference (PVP2008-61453 - Prevention of Transformer Tank Explosion: Part 2). The current paper shows the applications of this simulation software as a decision making tool, especially toward improving the design of real mechanical transformer protections. Some guidelines to optimize the efficiency of transformer protections are suggested thus contributing to a possible standard setting.

Landis, Ben, Omar Ahmed, Sangpil Yoon, Anne M. Goj, and Guillaume Périgaud. "Development of a Two-Way Fluid Structure Coupling for Studying Power Transformers Subjected to Internal Dynamic Over-Pressures." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97207.

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Within the highly competitive electricity market, companies often reduce costs by using aging equipment and by overloading their transformers. These conditions substantially increase the risk of transformer explosions. These incidents are caused by electrical arcs occurring within oil filled transformers. The arc, within milliseconds, vaporizes the surrounding oil and the generated gas is pressurized because the liquid inertia prevents its expansion. The pressure difference between the gas bubble and the surrounding liquid oil generates a dynamic pressure peak, which interacts with the transformer. The reflections generate pressure waves that lead to transformer rupture since transformers are not designed to withstand these pressures. This results in dangerous explosions, expensive damages and possible environmental pollution. Despite all these risks, and contrary to usual pressure vessels, no specific standard has been set to protect sealed transformer tanks subjected to large dynamic overpressures. In order to study transformer rupture and its prevention, experiments have been performed on transformers. However, safely carrying out live tests is difficult and expensive. In order to limit the costs, to reduce the risks and to gain insight on these phenomena numerical simulation tools are necessary. First a computational fluid dynamics solver was developed; it is based on an unsteady compressible two-phase flow model, the equations parameterizing the system are solved using a 3D finite volume method. Previous papers showed the ability of the hydrodynamic tool to study in detail (1) dynamic pressure wave propagation inside transformer oil that leads to transformer rupture and (2) depressurization induced by efficient protection means. Later, the hydrodynamic numerical tool has been one-way coupled with Code_ASTER, a dynamic structural analysis package, to create a fluid structure interaction (FSI). Preliminary results were shown and this strategy has been applied to the study of more complex electrical equipment. The present paper’s goal is to illustrate the development and application of a two-way coupling for the aforementioned fluid structure interaction strategy. The methodology for the enhanced coupling is explained and the simulation results about the structural behavior caused by these dynamic pressures are presented.

Sarkar, Subhas. "Developments in Traction Transformer." In 2012 Joint Rail Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/jrc2012-74098.

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Mass transit systems are gaining increased attention and popularity in the country. With this increased activity, more and more lines are getting added under public transit systems in more and more cities. One of the essential elements in the transit system is the traction transformer which powers the trains. With the emphasis on reliability, there is also increased awareness of the energy efficiency required of the traction substation equipments and the transformer in particular. Traction transformers are not ordinary power or distribution transformers. They have to meet several special requirements, including parameters like voltage regulation, impedance, commutation, short circuit withstand, operation with rectifiers, harmonic losses, wide fluctuation of load currents depending on the cyclic nature, etc. The reliability criteria are stringent and the traction transformers have to be properly designed, manufactured and tested, including short circuit testing for validation. Use of modern design tools like electric and magnetic field mapping and estimation of forces and stresses are helpful in computing them accurately. With the extensive use of vacuum circuit breakers, the subject of interaction of transformers and breakers have come to the foreground. New standards (like IEEE C57.142) have come into existence, which recommend methods to mitigate such effects. The author of this paper and his team has successfully applied these techniques in real life situations to solve problems. Work is in the final stages for preparation of a standard specifically for Traction Power Rectifier Transformers for transit applications (IEEE draft standard 1653.1) under the IEEE Vehicle Standards Committee.

Brady, Ryan, Se´bastien Muller, Gae¨l de Bressy, Philippe Magnier, and Guillaume Pe´rigaud. "Prevention of Transformer Tank Explosion: Part 2 — Development and Application of a Numerical Simulation Tool." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61453.

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Power transformers rank highly among the most dangerous electrical equipments because of the large quantity of oil they contain in direct contact with high voltage elements. Low impedance faults resulting in arcing can appear in transformer tanks if the oil loses its dielectric properties. Vaporization of the oil generates pressurized gas because the liquid inertia prevents expansion. The pressure difference between the gas bubbles and the surrounding liquid oil generates dynamic pressure waves which propagate and interact with the sealed tank structure. Simultaneously, the static pressure inside of the tank climbs and causes the tank to explode, resulting in fires and very expensive damages for electricity facilities. Despite all these risks, and contrary to usual pressure vessels, no specific standard exists as of yet to protect sealed transformer tanks subjected to large dynamic overpressures. This paper describes a complete numerical model for transformer explosions, which helps to understand all processes involved in such dramatic events, and helps design and optimize an efficient explosion prevention technology. Such a model includes various physical phenomena from the electrical arc description to the evaluation of the stress loads the transformer tank must withstand. The simulation tool kernel is based on a reduced 5 equation model introduced by Kapila et al. [8] to describe the hydrodynamic behavior of compressible 2-phase flows. It consists of a set of conservation laws for each phase partial-mass, the mixture momentum and energy, and volume fraction evolution equation. The closure is isobaric, and both phases have the same velocity at a given point. Each phase is described by its own equation of state. Physical effects such as electromagnetic forces, viscosity, thermal and gravity effects are also taken into account. These equations are solved on complex 3D transformer geometries using a finite volume strategy with unstructured meshes. Computer simulations are then used to study a fast-direct-tank-depressurization-based method to prevent the transformer explosions. Numerical results compare well with experimental results collected during arcing tests in oil filled transformers.

Muller, Se´bastien, Ryan Brady, Gae¨l De Bressy, Philippe Magnier, and Guillaume Pe´rigaud. "Prevention of Transformer Tank Explosion: Part 1 — Experimental Tests on Large Transformers." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61526.

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Oil-filled transformer explosions are caused by low impedance faults that result in arcing in transformer tanks once the oil loses its dielectric properties. Within milliseconds, oil is then vaporized and the generated gas is pressurized because the liquid inertia prevents its expansion. The pressure difference between the gas bubbles and the surrounding liquid oil generates pressure waves, which propagate and interact with the tank. Then, the pressure peak reflections are building up the static pressure, which rises and leads to the tank explosion since tanks are not designed to withstand the resulting static pressure. This typical transformer incident is common. Indeed, conventional transformer protections are unable to react fast enough to prevent tank explosion that usually result in very expensive blackouts and fire damages for electricity facilities. This paper describes a transformer explosion prevention technology based on the direct mechanical response of a Depressurization Set to the tank inner dynamic pressure induced by electrical faults. Since transformers always rupture at their weakest point because of the static pressure increase, the Depressurization Set is designed to be this weakest point in term of inertia to break before the tank explodes. To evaluate its efficiency, experiments and computer simulations have been performed. Two experimental test campaigns were carried out, first by Electricite´ de France in 2002 and second, by CEPEL, Brazil, in 2004 on large scale transformers equipped with that prevention technology. These tests consisted in creating low impedance faults in oil filled transformer tanks. The 62 tests confirmed that the arc first creates a huge volume of gas that is quickly pressurized, generating one high pressure peak that propagates in the oil and activates the transformer protection within milliseconds before static pressure increases, thus preventing the tank explosion. Beside the experiments, a compressible two-phase flow numerical simulation tool was developed. The theoretical bases of this tool are presented in a parallel paper [1] and it is used here to study the pressure increase in an unprotected tank when subjected to an internal arcing which properties are similar to those used during the experiments. The fast tank depressurization induced by the transformer protection and its protective effects are thus highlighted.

Tang, Liling, Peng Li, and Feng Jin. "The Theoretical and Numerical Analysis of Thickness-Shear Mode in a Two-Layered Piezoelectric Plate Transformer With a Viscoelastic Interface." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62770.

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A thickness-shear mode in a two-layered piezoelectric plate transformer with an imperfect interface is proposed. Based on the shear-slip interface model which is used to simulate the influence of viscoelastic imperfect interface, an exact solution from the three-dimensional equations of piezoelectricity is obtained. Numerical results reveal the effects of interface parameters on the transforming ratio, power density, input admittance, efficiency and displacement and stress distributions along the thickness direction, which could offer theoretical guidance in the design of piezoelectric transformers.

Simmons, Jeremy W., and James D. Van de Ven. "Switch-Mode Power Transformer in a Wave-Powered, Reverse Osmosis Desalination Plant." In ASME/BATH 2019 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/fpmc2019-1647.

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Abstract In the reverse osmosis (RO) desalination process, a salt water solution is pressurized to overcome the osmotic pressure across a semi-permeable membrane. A few groups have proposed that a wave energy converter (WEC) having a seawater based, hydraulic power take-off can could be used to pressurize the feedwater for an RO system. However, coupling the wave energy harvesting process and the RO desalination process imposes unique design constraints on the fluid power system, such as pressure limits of conventional RO system components. In this study, a fluid power circuit with a switch-mode power transformer is used to transfer power while keeping the pressure of the power take-off and RO processes relatively decoupled. The switch-mode power transformer studied herein adds fewer costly components and less significant loss mechanisms to the system than a conventional hydraulic transformer performing the same function. The switch-mode power transformer uses the inertia of a hydraulic motor driven electric generator and switching of the hydraulic motor inlet between high and low-pressure sources to decrease the pressure at which power is being transmitted to the RO process. This process is analogous to DC-DC switching power transformers in the electrical domain. This study seeks to demonstrate this unique switch-mode system as a potential solution for coupling the wave-energy harvesting process with the reverse osmosis process. The system is modeled and studied in the context that the transformer and RO system are onshore, 500 meters from the WEC. Power captured from the WEC is transmitted through a long pipeline to shore. A distributed parameter model is used to model the pipeline dynamics, simultaneously revealing the significance of these dynamics and the robustness with which the switch-mode transformer decouples the pressure dynamics at the RO feed from the pipeline dynamics. The switch-mode power transformer is estimated to be 76% efficient while the system, as a whole, is estimated to be 45% efficient.

Gupta, Ankit, Guy Dar, Shaya Goodman, David Ciprut, and Jonathan Berant. "Memory-efficient Transformers via Top-k Attention." In Proceedings of the Second Workshop on Simple and Efficient Natural Language Processing. Stroudsburg, PA, USA: Association for Computational Linguistics, 2021. http://dx.doi.org/10.18653/v1/2021.sustainlp-1.5.

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Molina, Paula Bastida, David Ribó-Pérez, Lina Montuori, and Carlos Vargas-Salgado. "“Innovation, creativity and entrepreneurship” transversal competence evaluation by technical-economic analysis of commercial electrical transformers." In INNODOCT 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/inn2019.2019.10115.

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“Innovation, creativity, and entrepreneurship” transversal competence evaluation method (CT04-UPV) used in Electrical Machines course (2nd course, Electrical Engineering Degree) is described in this paper. Its evaluation activity consists of a technical and economic analysis of different commercial electrical transformers, carried out by the students. To this end, students get in touch with electrical suppliers, obtaining real transformers data. With this data, they can calculate transformers efficiency through its energy losses and the economic cost that these losses suppose in a period of 10 years. In this way, students are able to question reality, identifying the existing necessity of evaluating not only its initial cost but also economic cost generated by its energy losses when selecting a transformer. With this method, CT04-UPV learning outcome referred to the 1st domain level is achieved: to question the reality, identifying improvement necessities and generating added value ideas. This methodology has been applied for the last three years in the course. In each year, students marks have been graded by the professor using a rubric. Results indicate that “innovation, creativity, and entrepreneurship” transversal competence learning outcome is satisfactorily reached by students. Moreover, rating survey answered by students, using Google Forms, shows that their level of satisfaction is very high.

Звіти організацій з теми "Transformers efficients":

Thomas L. Baldwin, Robert J. Turk, Kurt S. Myers, Jake P. Gentle, and Jason W. Bush. Transformer Efficiency Assessment - Okinawa, Japan. Office of Scientific and Technical Information (OSTI), May 2012. http://dx.doi.org/10.2172/1055976.

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Downing, D. J., B. W. McConnell, P. R. Barnes, S. W. Hadley, and J. W. Van Dyke. Economic analysis of efficient distribution transformer trends. Office of Scientific and Technical Information (OSTI), March 1998. http://dx.doi.org/10.2172/614511.

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Burkes, Klaehn, Joe Cordaro, John McIntosh, Benjamin McConnell, and Donald Hammerstrom. Efficient transformer study: Analysis of manufacture and utility data. Office of Scientific and Technical Information (OSTI), May 2017. http://dx.doi.org/10.2172/1362271.

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Letschert, Virginie, Michael McNeil, Jing Ke, Puneeth Kalavase, and Mahesh Sampat. Energy Efficiency Potential for Distribution Transformers in the APEC Economies. Office of Scientific and Technical Information (OSTI), July 2014. http://dx.doi.org/10.2172/1163743.

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Barnes, P. R., S. Das, B. W. McConnell, and J. W. Van Dyke. Supplement to the ``determination analysis`` (ORNL-6847) and analysis of the NEMA efficiency standard for distribution transformers. Office of Scientific and Technical Information (OSTI), September 1997. http://dx.doi.org/10.2172/666283.

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Shapira, Roni, Judith Grizzle, Nachman Paster, Mark Pines, and Chamindrani Mendis-Handagama. Novel Approach to Mycotoxin Detoxification in Farm Animals Using Probiotics Added to Feed Stuffs. United States Department of Agriculture, May 2010. http://dx.doi.org/10.32747/2010.7592115.bard.

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T-2 toxin, a toxic product belongs to the trichothecene mycotoxins, attracts major interest because of its severe detrimental effects on the health of human and farm animals. The occurrence of trichothecenes contamination is global and they are very resistant to physical or chemical detoxification techniques. Trichothecenes are absorbed in the small intestine into the blood stream. The hypothesis of this project was to develop a protecting system using probiotic bacteria that will express trichothecene 3-O-acetyltransferase (Tri101) that convert T-2 to a less toxic intermediate to reduce ingested levels in-situ. The major obstacle that we had faced during the project is the absence of stable and efficient expression vectors in probiotics. Most of the project period was invested to screen and isolate strong promoter to express high amounts of the detoxify enzyme on one hand and to stabilize the expression vector on the other hand. In order to estimate the detoxification capacity of the isolated promoters we had developed two very sensitive bioassays.The first system was based on Saccharomyces cerevisiae cells expressing the green fluorescent protein (GFP). Human liver cells proliferation was used as the second bioassay system.Using both systems we were able to prove actual detoxification on living cells by probiotic bacteria expressing Tri101. The first step was the isolation of already discovered strong promoters from lactic acid bacteria, cloning them downstream the Tri101 gene and transformed vectors to E. coli, a lactic acid bacteria strain Lactococcuslactis MG1363, and a probiotic strain of Lactobacillus casei. All plasmid constructs transformed to L. casei were unstable. The promoter designated lacA found to be the most efficient in reducing T-2 from the growth media of E. coli and L. lactis. A prompter library was generated from L. casei in order to isolate authentic probiotic promoters. Seven promoters were isolated, cloned downstream Tri101, transformed to bacteria and their detoxification capability was compared. One of those prompters, designated P201 showed a relatively high efficiency in detoxification. Sequence analysis of the promoter region of P201 and another promoter, P41, revealed the consensus region recognized by the sigma factor. We further attempted to isolate an inducible, strong promoter by comparing the protein profiles of L. casei grown in the presence of 0.3% bile salt (mimicking intestine conditions). Six spots that were consistently overexpressed in the presence of bile salts were isolated and identified. Their promoter reigns are now under investigation and characterization.

Zhou, Ting, Roni Shapira, Peter Pauls, Nachman Paster, and Mark Pines. Biological Detoxification of the Mycotoxin Deoxynivalenol (DON) to Improve Safety of Animal Feed and Food. United States Department of Agriculture, July 2010. http://dx.doi.org/10.32747/2010.7613885.bard.

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The trichothecene deoxynivalenol (DON, vomitoxin), one of the most common mycotoxin contaminants of grains, is produced by members of the Fusarium genus. DON poses a health risk to consumers and impairs livestock performance because it causes feed refusal, nausea, vomiting, diarrhea, hemolytic effects and cellular injury. The occurrence of trichothecenes contamination is global and they are very resistant to physical or chemical detoxification techniques. Trichothecenes are absorbed in the small intestine into the blood stream. The overall objective of this project was to develop a protecting system using probiotic bacteria that will express trichothecene 3-O-acetyltransferase (Tri101) that convert T-2 to a less toxic intermediate to reduce ingested levels in-situ. The major obstacle that we had faced during the project is the absence of stable and efficient expression vectors in probiotics. Most of the project period was invested to screen and isolate strong promoter to express high amounts of the detoxify enzyme on one hand and to stabilize the expression vector on the other hand. In order to estimate the detoxification capacity of the isolated promoters we had developed two very sensitive bioassays.The first system was based on Saccharomyces cerevisiae cells expressing the green fluorescent protein (GFP). Human liver cells proliferation was used as the second bioassay system.Using both systems we were able to prove actual detoxification on living cells by probiotic bacteria expressing Tri101. The first step was the isolation of already discovered strong promoters from lactic acid bacteria, cloning them downstream the Tri101 gene and transformed vectors to E. coli, a lactic acid bacteria strain Lactococcuslactis MG1363, and a probiotic strain of Lactobacillus casei. All plasmid constructs transformed to L. casei were unstable. The promoter designated lacA found to be the most efficient in reducing T-2 from the growth media of E. coli and L. lactis. A prompter library was generated from L. casei in order to isolate authentic probiotic promoters. Seven promoters were isolated, cloned downstream Tri101, transformed to bacteria and their detoxification capability was compared. One of those prompters, designated P201 showed a relatively high efficiency in detoxification. Sequence analysis of the promoter region of P201 and another promoter, P41, revealed the consensus region recognized by the sigma factor. We further attempted to isolate an inducible, strong promoter by comparing the protein profiles of L. casei grown in the presence of 0.3% bile salt (mimicking intestine conditions). Six spots that were consistently overexpressed in the presence of bile salts were isolated and identified. Their promoter reigns are now under investigation and characterization.

Lever, James, and Jason Weale. High efficiency fuel sleds for Polar traverses. Engineer Research and Development Center (U.S.), March 2022. http://dx.doi.org/10.21079/11681/43445.

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We describe here the evolution of lightweight, high-efficiency fuel sleds for Polar over-snow traverses. These sleds consist of flexible bladders strapped to sheets of high molecular weight polyethylene. They cost 1/6th, weigh 1/10th and triple the fuel delivered per towing tractor compared with steel sleds. An eight-tractor fleet has conducted three 3400-km roundtrips to South Pole with each travers delivering 320,000 kg of fuel while emitting <1% the pollutants, consuming 1/2 the fuel and saving $1.6 M compared with aircraft resupply. A two tractor fleet in Greenland recently delivered 83,000 kg of fuel in bladder sleds to Summit with similar benefits. Performance monitoring has revealed that bladder-sled towing resistance is largely governed by sliding friction, which can start high and drop in half over the first 30 min of travel. Frictional heating probably produces a thin water layer that lubricates the sled–snow interface. Consequently, towing resistance depends on the thermal budget of the sled. For example, black fuel bladders increase solar gain and thus decrease sled resistance; data suggest they could double again the fuel delivered per tractor. The outstanding efficiency and low cost of these sleds has transformed fuel delivery to Polar research stations.