Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 94-95). Also available via the Internet.

A non-invasive, on-line method for detection of mechanical (rotor, bearings eccentricity) and stator winding faults in a 3-phase induction motors from observation of motor line current supply input. The main aim is to avoid the consequence of unexpected failure of critical equipment which results in extended process shutdown, costly machinery repair, and health and safety problems. This thesis looks into the possibility of utilizing machine learning techniques in the field of condition monitoring of electromechanical systems. Induction motors are chosen as an example for such application. Electrical motors play a vital role in our everyday life. Induction motors are kept in operation through monitoring its condition in a continuous manner in order to minimise their off times. The author proposes a model free sensor-less monitoring system, where the only monitored signal is the input to the induction motor. The thesis considers different methods available in literature for condition monitoring of induction motors and adopts a simple solution that is based on monitoring of the motor current. The method proposed use the feature extraction and Support Vector Machines (SVM) to set the limits for healthy and faulty data based on the statistical methods. After an extensive overview of the related literature and studies, the motor which is the virtual sensor in the drive system is analysed by considering its construction and principle of operation. The mathematical model of the motor is used for analysing the system. This is followed by laboratory testing of healthy motors and comparing their output signals with those of the same motors after being intentionally failed, concluding with the development of a full monitoring system. Finally, a monitoring system is proposed that can detect the presence of a fault in the monitored machine and diagnose the fault type and severity

Introdução: No acompanhamento diário de pacientes que realizam troca de sonda de gastrostomia endoscópica percutânea (GEP), observa-se a preco- cidade com que ocorrem essas trocas devido à curta durabilidade da sonda, especialmente decorrente da ruptura do balão interno da sonda. Objetivo: Este estudo prospectivo visou à avaliação da durabilidade de cinco diferen- tes marcas de sondas de troca de GEP. Método: Cem procedimentos con- secutivos de troca de sonda de GEP (realizados em 65 pacientes) foram dis- tribuídos, a cada grupo de 20 procedimentos, em cinco grupos determinados pelas marcas de sondas avaliadas (Kangaroo®, Wilson Cook®, Silmag®, Fre- ka® e Bard®). Conforme o protocolo proposto, após a troca, os pacientes fo- ram seguidos ao longo de seis meses, e, nesse período, foram realizadas três avaliações para verificação de eventuais intercorrências. Para avaliação da durabilidade das sondas, foi considerado o período de permanência dos pacientes no protocolo, determinada pelo término do período de estudo ou pela necessidade de troca da sonda por ruptura do balão ou desgaste do tubo ou da tampa. As curvas de durabilidade das sondas foram determina- das pelo Método de Kaplan Meier e pelo Modelo de Regressão de Cox. Resultados: Houve variações importantes na durabilidade das sondas quando considerados os três motivos de troca da sonda associados. Essa diferença não foi observada quando se considerou apenas a ruptura do balão, cujas ocorrências se mostraram associadas com pacientes em uso de GEP por distúrbios neurológicos sem diagnóstico. A durabilidade das sondas foi tanto menor, quanto maior o número de trocas anteriores. Conclusões: A marca da sonda de troca de GEP não influenciou a sua durabilidade quando deter- minada pela ruptura do balão, mas, quando determinada também por des- gaste em tubo e tampa, as sondas Wilson Cook® apresentaram durabilidade significativamente maior do que as sondas Silmag® e Bard®. O número de trocas anteriores se mostrou fator determinante de menor durabilidade das sondas / Introduction: During the follow-up of patients after replacement of percuta- neous endoscopic gastrostomy (PEG) tubes, the early need of new replace- ments seems to be consequence of the short durability of the tubes, espe- cially due to the rupture of their internal balloon. Objectives: In this prospec- tive study, the durability of five different PEG tubes was estimated. Methods: One hundred consecutive procedures (in 65 patients) for replacing PEG tubes were divided into five groups determined by the tubes model: Kanga- roo®, Wilson Cook®, Silmag®, Freka® and Bard®. According to the protocol developed for the study, patients were followed up along six months, and three evaluations for verifying eventual outcomes were carried out during this period. Estimation of the tubes durability considered the time patients re- mained in the protocol, which was determined by the termination of the follow up period or by the need for replacing the tubes due to the balloon rupture or to the loss of use of tube or cover. Curves of tubes durability were estab- lished by applying the Kaplan-Meier Method and the Cox Regression Model. Results: Important variations of the tubes durability were observed when the three causes for replacement were considered all together. Differences were not observed when considered only the balloon rupture, which was associated with patients using PEG in virtue of not specified neurologic disorders. Shorter tubes durability was associated with more previous replacements. Spontaneous opening of the cover and slipping of the external protection were significantly less frequent in the Freka® tubes, although such outcomes did not determined the tubes durability. Conclusion: The model of PEG re- placement tubes did not influence their durability regarding the balloon rup- ture alone. Considering such occurrence associated with problems in tubes or covers, the longest durability was observed in Wilson Cook®, followed by Freka, ® Kangaroo®, Silmag® and Bard® tubes. The number of previous re- placements showed to be determining factor for the tubes durability

Introdução: No acompanhamento diário de pacientes que realizam troca de sonda de gastrostomia endoscópica percutânea (GEP), observa-se a preco- cidade com que ocorrem essas trocas devido à curta durabilidade da sonda, especialmente decorrente da ruptura do balão interno da sonda. Objetivo: Este estudo prospectivo visou à avaliação da durabilidade de cinco diferen- tes marcas de sondas de troca de GEP. Método: Cem procedimentos con- secutivos de troca de sonda de GEP (realizados em 65 pacientes) foram dis- tribuídos, a cada grupo de 20 procedimentos, em cinco grupos determinados pelas marcas de sondas avaliadas (Kangaroo®, Wilson Cook®, Silmag®, Fre- ka® e Bard®). Conforme o protocolo proposto, após a troca, os pacientes fo- ram seguidos ao longo de seis meses, e, nesse período, foram realizadas três avaliações para verificação de eventuais intercorrências. Para avaliação da durabilidade das sondas, foi considerado o período de permanência dos pacientes no protocolo, determinada pelo término do período de estudo ou pela necessidade de troca da sonda por ruptura do balão ou desgaste do tubo ou da tampa. As curvas de durabilidade das sondas foram determina- das pelo Método de Kaplan Meier e pelo Modelo de Regressão de Cox. Resultados: Houve variações importantes na durabilidade das sondas quando considerados os três motivos de troca da sonda associados. Essa diferença não foi observada quando se considerou apenas a ruptura do balão, cujas ocorrências se mostraram associadas com pacientes em uso de GEP por distúrbios neurológicos sem diagnóstico. A durabilidade das sondas foi tanto menor, quanto maior o número de trocas anteriores. Conclusões: A marca da sonda de troca de GEP não influenciou a sua durabilidade quando deter- minada pela ruptura do balão, mas, quando determinada também por des- gaste em tubo e tampa, as sondas Wilson Cook® apresentaram durabilidade significativamente maior do que as sondas Silmag® e Bard®. O número de trocas anteriores se mostrou fator determinante de menor durabilidade das sondas / Introduction: During the follow-up of patients after replacement of percuta- neous endoscopic gastrostomy (PEG) tubes, the early need of new replace- ments seems to be consequence of the short durability of the tubes, espe- cially due to the rupture of their internal balloon. Objectives: In this prospec- tive study, the durability of five different PEG tubes was estimated. Methods: One hundred consecutive procedures (in 65 patients) for replacing PEG tubes were divided into five groups determined by the tubes model: Kanga- roo®, Wilson Cook®, Silmag®, Freka® and Bard®. According to the protocol developed for the study, patients were followed up along six months, and three evaluations for verifying eventual outcomes were carried out during this period. Estimation of the tubes durability considered the time patients re- mained in the protocol, which was determined by the termination of the follow up period or by the need for replacing the tubes due to the balloon rupture or to the loss of use of tube or cover. Curves of tubes durability were estab- lished by applying the Kaplan-Meier Method and the Cox Regression Model. Results: Important variations of the tubes durability were observed when the three causes for replacement were considered all together. Differences were not observed when considered only the balloon rupture, which was associated with patients using PEG in virtue of not specified neurologic disorders. Shorter tubes durability was associated with more previous replacements. Spontaneous opening of the cover and slipping of the external protection were significantly less frequent in the Freka® tubes, although such outcomes did not determined the tubes durability. Conclusion: The model of PEG re- placement tubes did not influence their durability regarding the balloon rup- ture alone. Considering such occurrence associated with problems in tubes or covers, the longest durability was observed in Wilson Cook®, followed by Freka, ® Kangaroo®, Silmag® and Bard® tubes. The number of previous re- placements showed to be determining factor for the tubes durability

Orientador: Alberto Cliquet Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T22:08:58Z (GMT). No. of bitstreams: 1 Ravaglia_FabioFerrazdoAmaral_M.pdf: 3548953 bytes, checksum: 43be45b122388651863a7129f73a3c73 (MD5) Previous issue date: 2008 / Mestrado / Cirurgia / Mestre em Cirurgia

Orientador: Roger William Fernandes Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-21T14:42:14Z (GMT). No. of bitstreams: 1 Mendes_MarceloBrenoMeneses_M.pdf: 5487742 bytes, checksum: e1f89d1bc60060a4c330175efda763d9 (MD5) Previous issue date: 2012 / Resumo: Este trabalho tem o objetivo de analisar, através de metalografia, análise da composição de gases oxigênio e nitrogênio e por meio de teste de dureza Vickers, 4 marcas de material de fixação interna utilizadas na cirurgia buco-maxilo-facial (grupo I = Leibinger; grupo II = Tóride; grupo III = Engimplan; grupo IV = Medartis). Inicialmente, foram confeccionados três corpos de prova com segmento de placa de três elos e três corpos de prova com parafusos, para cada grupo. Realizou-se preparação e análise metalográfica, de acordo com as normas da ASTM E3-95. Em seguida, as amostras foram submetidas ao teste de dureza Vickers, obedecendo às normas da ASTM E92. Após, foi realizado análise da composição de gases oxigênio e nitrogênio, com um segmento de elo de placa e um parafuso, para cada grupo. Os dados foram submetidos à análise de variância e teste de Tukey para comparação dos resultados. Todas as etapas dos processos foram registradas e fotografadas. De acordo com os resultados encontrados, os parafusos apresentaram maior dureza, em comparação com as placas. Entre estas, as placas do grupo IV apresentaram os grãos de maiores dimensão. A análise da composição dos gases revelou que todos os grupos atendem às normas ASTM / Abstract: This study aims to analyze 04 brands of internal fixation material, used in oral and maxillofacial surgery (Leibinger = group I; Tóride = group II; Engimplan = group III; Medartis = group IV) by metallography, analyzing the composition of gaseous oxygen (O) and nitrogen (N), and Vickers hardness testing. Initially,three specimens with three rings of the plate and three specimens with screws were made for each group. The preparation of the specimens was performed to metallographic analysis, attending the ASTM E3-95 standards. And then the samples were submitted to Vickers hardness test, according to the ASTM E92 standards. Thereafter, the composition analysis of the contents of O and N in all groups was performed with a ring of the plate and a screw for each group. Data were submitted to ANOVA and Tukey's test for result comparison. All steps of the process were recorded and photographed. According to the results, the screws had higher hardness, compared to the plates. Including, the plates of group IV showed the largest grain size. The analysis of the gas composition showed that all groups followed ASTM standards / Mestrado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Mestre em Clínica Odontológica

Aseptic loosening of the components is probably the most common long-term complication resulting in failure of Total Hip Arthroplasty. The mechanical behaviour of bone under load is one of the contributory causes of loosening encountered at the prosthesis/cement/bone interface. The present study dealt with a series of invitro experiments conducted on epoxy resin models of human hemi-pelves with different commercially available acetabular components implanted in them. These are used for the construction of simplified models of the artificial hip joint (three-dimensional) and of the prosthesis/cement/bone acetabular interface (two-dimensional). Loading conditions for the models included tensioning of the simulated abductor muscles for the hemi-pelvic and femoral loading for the prosthesis/cement/bone interface study. The experimental method employed was real-time holographic interferometry, a stress analysis technique recently used in the biomechanical field, which permitted whole-field simultaneously inspection of deformation patterns. The holographic interferograms were interpreted in a qualitative rather than a quantitative manner. The models do not exactly represent the in-vivo situation. Since this study identified high stresses both in the hip bone as well as in the interface (prosthesis/bone) it is suggested that these stresses are implicated in the mechanical pathogenesis of loosening. The observed changes in stress levels detected in our models could serve as a guide for future designs of acetabular prostheses as well as guide a in surgical techniques.

A non-invasive, on-line method for detection of mechanical (rotor, bearings eccentricity) and stator winding faults in a 3-phase induction motors from observation of motor line current supply input. The main aim is to avoid the consequence of unexpected failure of critical equipment which results in extended process shutdown, costly machinery repair, and health and safety problems. This thesis looks into the possibility of utilizing machine learning techniques in the field of condition monitoring of electromechanical systems. Induction motors are chosen as an example for such application. Electrical motors play a vital role in our everyday life. Induction motors are kept in operation through monitoring its condition in a continuous manner in order to minimise their off times. The author proposes a model free sensor-less monitoring system, where the only monitored signal is the input to the induction motor. The thesis considers different methods available in literature for condition monitoring of induction motors and adopts a simple solution that is based on monitoring of the motor current. The method proposed use the feature extraction and Support Vector Machines (SVM) to set the limits for healthy and faulty data based on the statistical methods. After an extensive overview of the related literature and studies, the motor which is the virtual sensor in the drive system is analysed by considering its construction and principle of operation. The mathematical model of the motor is used for analysing the system. This is followed by laboratory testing of healthy motors and comparing their output signals with those of the same motors after being intentionally failed, concluding with the development of a full monitoring system. Finally, a monitoring system is proposed that can detect the presence of a fault in the monitored machine and diagnose the fault type and severity / Ministry of Higher Education, Libya; Switchgear & Instruments Ltd.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.