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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.
11

Surface modification and chromophore attachment via ionic assembly and covalent fixation

Hubbell, Christopher 09 January 2009 (has links)
A reactive-ionic functional group was incorporated into the structure of fiber finishes and colorants to provide high-yield add-on and permanency. The reactive-ionic group consists of a moderately strained, cyclic ammonium group which undergoes ionic assembly on the surface of negatively charged substrates. The ionic bond is then converted to a covalent bond at elevated temperatures via a ring-opening reaction. A reactive-ionic alkyl (wax) finish was prepared from octadecanol and N-phenyl pyrrolidine then applied to a glass slide to provide a permanent, hydrophobic surface with an average contact angle increase of approximately 40°. A reactive-ionic fluorinated finish was prepared from 1H,1H,2H,2H-perfluoro-1-octanol and N-phenyl pyrrolidine and after application served as a permanent, non-wetting, anti-stain finish for nylon carpet. A reactive-ionic chromophore (dye) was prepared from C.I. Disperse Red 1 and quinuclidine. The reactive-ionic dye was applied to cellophane and nylon films and bleached cotton, nylon and silk fabrics. The percent exhaustion for a 1% owf dyeing of silk fabric was measured to be 98% using visible light absorbance spectrophotometry. K/S values obtained from reflectance spectrophotometric measurements of a 1% owf dyeing of nylon 6,6 fabric showed a 6% color loss after solvent extraction, indicating that the dyeing was indeed permanent.
12

Evaluation of secondary wire bond integrity on silver plated and nickel/palladium based lead frame plating finishes

Srinivasan, Guruprasad. January 2008 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.
13

Aplicação de redes neurais artificiais no monitoramento da operação de dressagem

Grizzo, Daniela Fernanda [UNESP] 06 July 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-06Bitstream added on 2014-06-13T19:36:43Z : No. of bitstreams: 1 moia_dfg_me_bauru.pdf: 2028523 bytes, checksum: a4957573090c9f2211022b6a4fceb9b6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O processo de retificação confere à peça o acabamento final, minimizando as irregularidades superficiais através de interações entre os grãos abrasivos de uma ferramenta (rebolo) e peça retificada. O desgaste do rebolo devido ao atrito entre o rebolo e a peça retificada torna a ferramenta inadequada para nova utilização, sendo necessária a realização do processo de dressagem do rebolo para remoção e ou avivamento dos grãos gastos de sua superfície de corte, de forma e deixá-lo em condições para novo uso. O presente trabalho tem como objetivo classificar a condição do rebolo durante a operação de dressagem utilizando o sinal de emissão acústica (EA) e estatísticas derivadas desse sinal, por meio de redes neurais artificiais. Nos experimentos realizados usou-se um rebolo de óxido de alumínio instalado em uma retificadora plana, um sistema de aquisição de sinais e um dressador de ponta única de diamante. O processamento digital de sinais foi obtido através do software MATLAB. Os ensaios foram realizados com diferentes graus de recobrimento e profundidade de dressagem. A partir dos dados obtidos de EA puro, calculou-se o valor médio quadrático (RMS), bem como mais duas estatísticas, as quais já foram empregadas com sucesso em trabalhos de detecção de queima, no processo de retificação. Essas estatísticas também se mostraram bons indicadores para o monitoramento da operação de dressagem. Uma rede neural perceptron multicamadas (MLP) foi utilizada com o algoritmo de aprendizado Levenberg-Marquardt, cujas entradas foram as duas estatísticas mencionadas e o valor RMS de EA. Os resultados mostram que o método empregado foi capaz de classificar as condições do rebolo no processo de dressagem, identificando o rebolo como afiado (com capacidade de corte) e rebolo se afiação (com perda de capacidade de corte), viabilizando a redução do tempo e custo dessa operação e minimizando a remoção excessiva / The grinding process gives the piece a final finish by minimizing surface irregularities through interactions between the abrasive grains of a tool (wheel) and the part to be ground. The wear of the grinding wheel due to excessive friction between the grinding wheel and ground workpiece makes the tool unsuitable for further use; it is imperative the accomplishment of the process of dressing the grinding wheel to remove or resharpen the worn grains of its surface in order to make if suitable for use again. The present study aims to classify the condition of the grinding wheel during operation using acoustic emission (AE) signal and statistics derived from this sinal through artificial neural networks. In the experiments an aluminum oxide grinding wheel installed to a surface grinding machine was used along with a data acquisition system and a single point diamond dresser. The digital processing of these data was obtained using the MATLAB software. Tests were performed with different overlap ratio and depth of cut. The root mean square value of the AE signal as well as two other statistics were obtained from the raw acoustic emission signal, which have been successfully used in grinding burn detection. These statistics were also good indicators for monitoring the dressing operation. A multilayer perceptron neural network (MLP) was used with the learning algorithm Levenberg-Marquardt, whose inputs were the statistics previously mentioned and dressing conditions. The results show that the method used was able to classify the conditions of the grinding wheel in the process of dressing, identifying the wheel as sharp (cutting capacity) and dull (with loss of cutting capacity), enabling the reduction of time and cost of operation and minimizing the excessive removal of the wheel abrasive material
14

Aplicação de redes neurais artificiais no monitoramento da operação de dressagem /

Grizzo, Daniela Fernanda. January 2012 (has links)
Orientador: Paulo Roberto de Aguiar / Banca: Carlos Elias da Silva Junior / Banca:m Eduardo Carlos Bianchi / Resumo: O processo de retificação confere à peça o acabamento final, minimizando as irregularidades superficiais através de interações entre os grãos abrasivos de uma ferramenta (rebolo) e peça retificada. O desgaste do rebolo devido ao atrito entre o rebolo e a peça retificada torna a ferramenta inadequada para nova utilização, sendo necessária a realização do processo de dressagem do rebolo para remoção e ou avivamento dos grãos gastos de sua superfície de corte, de forma e deixá-lo em condições para novo uso. O presente trabalho tem como objetivo classificar a condição do rebolo durante a operação de dressagem utilizando o sinal de emissão acústica (EA) e estatísticas derivadas desse sinal, por meio de redes neurais artificiais. Nos experimentos realizados usou-se um rebolo de óxido de alumínio instalado em uma retificadora plana, um sistema de aquisição de sinais e um dressador de ponta única de diamante. O processamento digital de sinais foi obtido através do software MATLAB. Os ensaios foram realizados com diferentes graus de recobrimento e profundidade de dressagem. A partir dos dados obtidos de EA puro, calculou-se o valor médio quadrático (RMS), bem como mais duas estatísticas, as quais já foram empregadas com sucesso em trabalhos de detecção de queima, no processo de retificação. Essas estatísticas também se mostraram bons indicadores para o monitoramento da operação de dressagem. Uma rede neural perceptron multicamadas (MLP) foi utilizada com o algoritmo de aprendizado Levenberg-Marquardt, cujas entradas foram as duas estatísticas mencionadas e o valor RMS de EA. Os resultados mostram que o método empregado foi capaz de classificar as condições do rebolo no processo de dressagem, identificando o rebolo como "afiado" (com capacidade de corte) e rebolo "se afiação" (com perda de capacidade de corte), viabilizando a redução do tempo e custo dessa operação e minimizando a remoção excessiva / Abstract: The grinding process gives the piece a final finish by minimizing surface irregularities through interactions between the abrasive grains of a tool (wheel) and the part to be ground. The wear of the grinding wheel due to excessive friction between the grinding wheel and ground workpiece makes the tool unsuitable for further use; it is imperative the accomplishment of the process of dressing the grinding wheel to remove or resharpen the worn grains of its surface in order to make if suitable for use again. The present study aims to classify the condition of the grinding wheel during operation using acoustic emission (AE) signal and statistics derived from this sinal through artificial neural networks. In the experiments an aluminum oxide grinding wheel installed to a surface grinding machine was used along with a data acquisition system and a single point diamond dresser. The digital processing of these data was obtained using the MATLAB software. Tests were performed with different overlap ratio and depth of cut. The root mean square value of the AE signal as well as two other statistics were obtained from the raw acoustic emission signal, which have been successfully used in grinding burn detection. These statistics were also good indicators for monitoring the dressing operation. A multilayer perceptron neural network (MLP) was used with the learning algorithm Levenberg-Marquardt, whose inputs were the statistics previously mentioned and dressing conditions. The results show that the method used was able to classify the conditions of the grinding wheel in the process of dressing, identifying the wheel as sharp (cutting capacity) and dull (with loss of cutting capacity), enabling the reduction of time and cost of operation and minimizing the excessive removal of the wheel abrasive material / Mestre

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