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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Parameterization of Pulses from a Particle Detector Using a FlashADC

Huang, Yunyi January 2014 (has links)
With the deep exploration of particle physics, particle accelerators, detection methods, data recording and processing, and application of computing technology are continuously developing. It has not only brought progress in particle physics, but also promoted the development of the Science and Technology. The main focus of this thesis is data recording and processing. It provides a calibration method for pulses processed by ADCs. It uses some existing filters to achieve the accurate parameters of pulses and existing concept to do the comparison among filters. The  FPGA implementation scheme is also discussed in the paper.
2

Assessing the effects of GMAW-pulse parameters on arc power and weld heat input

Joseph, Andrew Paul January 2001 (has links)
No description available.
3

Influ?ncia da corrente de pulso, do tempo de pulso e di?metro de gota sobre a estabilidade da transfer?ncia met?lica no processo MIG-P

Andrade, Augusto Fernandes Cordeiro de 17 September 2012 (has links)
Made available in DSpace on 2014-12-17T14:58:18Z (GMT). No. of bitstreams: 1 AugustoFCA_DISSERT.pdf: 3840311 bytes, checksum: ce8a1af807b0e69bd76433af2127d588 (MD5) Previous issue date: 2012-09-17 / To obtain a process stability and a quality weld bead it is necessary an adequate parameters set: base current and time, pulse current and pulse time, because these influence the mode of metal transfer and the weld quality in the MIG-P, sometimes requiring special sources with synergistic modes with external control for this stability. This work aims to analyze and compare the effects of pulse parameters and droplet size in arc stability in MIG-P, four packets of pulse parameters were analysed: Ip = 160 A, tp = 5.7 ms; Ip = 300 A and tp = 2 ms, Ip = 350 A, tp = 1.2 ms and Ip = 350 A, tp = 0.8 ms. Each was analyzed with three different drop diameters: drop with the same diameter of the wire electrode; droplet diameter larger drop smaller than the diameter of the wire electrode. For purposes of comparison the same was determined relation between the average current and welding speed was determined generating a constant (Im / Vs = K) for all parameters. Welding in flat plate by simple deposition for the MIG-P with a distance beak contact number (DBCP) constant was perfomed subsequently making up welding in flat plate by simple deposition with an inclination of 10 degrees to vary the DBCP, where by assessment on how the MIG-P behaved in such a situation was possible, in addition to evaluating the MIG-P with adaptive control, in order to maintain a constant arc stability. Also high speed recording synchronized with acquiring current x voltage (oscillogram) was executed for better interpretation of the transfer mechanism and better evaluation in regard to the study of the stability of the process. It is concluded that parameters 3 and 4 exhibited greater versatility; diameters drop equal to or slightly less than the diameter of the wire exhibited better stability due to their higher frequency of detachment, and the detachment of the drop base does not harm the maintenance the height of the arc / Para obter a estabilidade no processo e uma boa qualidade no cord?o de solda ? necess?rio um bom ajuste nos par?metros: corrente e tempo de base e corrente e tempo de pulso e Va, pois estes influenciam no modo de transfer?ncia met?lica e sobre a qualidade da solda no processo MIG-P, ?s vezes, sendo necess?rio um aux?lio ?s fontes com os modos sin?rgicos com controle externo para obter esta estabilidade. Este trabalho tem como objetivo analisar e comparar os efeitos dos par?metros de pulso e o di?metro de gota na estabilidade do arco voltaico no processo MIG-P, sendo analisados quatro pacotes de par?metros de pulso: Ip=160 A, tp=5,7 ms; Ip=300 A e tp=2 ms; Ip=350 A, tp=1,2 ms; e Ip=350 A, tp=0,8 ms. Cada um foi analisado com tr?s diferentes di?metros, calculados, de gota: gota com o mesmo di?metro do arame-eletrodo; gota com di?metro de gota maior e menor que o di?metro do arame eletrodo. Para fins de compara??o foi determinada a mesma rela??o entre a corrente m?dia e a velocidade de soldagem gerando uma constante (Im/Vs=K) para todos os par?metros. Realizou-se a soldagem em chapa plana por simples deposi??o para o processo MIG-P com uma dist?ncia bico contato pe?a (DBCP) constante; e posteriormente, efetuando-se a soldagem em chapa plana por simples deposi??o com uma inclina??o de 10? para variar o DBCP, p?de-se avaliar como o MIG-P se comportou em tal situa??o, al?m de avaliar o MIG-P com controle adaptativo, com o objetivo de manter constante a estabilidade do arco voltaico. Tamb?m executou-se a filmagem de alta velocidade sincronizadamente a aquisi??o da corrente x tens?o (oscilograma) para melhor interpreta??o do mecanismo de transfer?ncia e melhor avalia??o no que se refere ao estudo da estabilidade do processo. Conclu?mos que os par?metros 3 e 4 apresentaram uma maior versatilidade; os di?metros de gota igual ou ligeiramente menos que o di?metro do arame apresentaram uma melhor estabilidade, devido a sua maior frequ?ncia de destacamento; e o destacamento da gota na base n?o prejudicou a manuten??o da altura do arco voltaico

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