Loading and aging of electrical power transformers and main aspects to condition-based maintenance

Orientador: José Pissolato FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: O transformador é o maior ativo, o mais importante e o mais caro do sistema elétrico de potência. Este estudo tem a finalidade de apresentar uma metodologia e um processo de análise do ciclo de vida útil de transformadores de potência baseada na condição, para evitar perda de vida adicional devido ao acréscimo de carga em condição de contingência no sistema. A abordagem foi feita em duas fases e abrangem tanto a metodologia da norma ABNT como a norma do IEEE. Na primeira fase é verificado o comportamento do modelo térmico devido a sobrecargas e, na segunda, a influência das condições do óleo isolanteAbstract: The transformer is the largest, most expensive, most important asset in the electric power system. This study will present a methodology to analyze the useful life of power transformers based on their condition, in order to avoid incremental loss of life caused by overload under contingent operating conditions. The approach has been performed in two phases, following both ABNT and IEEE standards. In the first phase, a thermal model evaluates the effect of overloads on transformers' useful life. In the second phase, the influence of the conditions of the insulating oil is verifiedMestradoEnergia EletricaMestre em Engenharia Elétric

Experience with Biosynthetic Human Insulin in Diabetes

Thirty diabetic patients new to insulin were entered in an open label prospective study of biosynthetic human insulin (BHI). All patients experienced symptomatic control of diabetes attributable to dietary and BHI insulin therapy. Detailed six-month evaluation data were reviewed in 19 patients. A significant drop in fasting plasma glucose and glycosylated hemoglobin was noted at two months, and a further modest decrease occurred at six months. E. coli polypeptide antibodies were unchanged from baseline at six months, indicating that no bacterial protein contamination of BHI occurred. Percent binding of serum antibodies to human insulin measured in 19 patients at baseline and at six months showed a statistically significant increase in mean value without accompanying clinical symptoms. Clinical hypoglycemia did not differ from that seen in patients who received animal insulin. Biosynthetic human insulin appears comparable in clinical efficacy and safety to purified pork insulin. Ongoing studies will be required to determine whether BHI is less immunogenic than purified pork insulin

Angiographic Findings and Outcome in Diabetec Patients Treated With Thrombolytic Therapy for Acute Myocardial Infarction: The GUSTO-I Experience

OBJECTIVES: This study sought to determine whether diabetes mellitus, in the setting of thrombolysis for acute myocardial infarction, affects 1) early infarct-related artery patency and reocclusion rates; and 2) global and regional ventricular function indexes. We also sought to assess whether angiographic or baseline clinical variables, or both, can account for the known excess mortality after myocardial infarction in the diabetic population. BACKGROUND: Mortality after acute myocardial infarction in patients with diabetes is approximately twice that of nondiabetic patients. It is uncertain whether this difference in mortality is due to a lower rate of successful thrombolysis, increased reocclusion after successful thrombolysis, greater ventricular injury or a more adverse angiographic or clinical profile in diabetic patients. METHODS: Patency rates and global and regional left ventricular function were determined in patients enrolled in the GUSTO-I Angiographic Trial. Thirty-day mortality differences between those with and without diabetes were compared. RESULTS: The diabetic cohort had a significantly higher proportion of female and elderly patients, and th

Le grand tabou : l'amour surréaliste en Égypte

Dans ce mémoire, il est intéressant de faire une comparaison entre la France et l’Égypte. Nous avons choisi la France comme pays fondateur, car le surréalisme est né à Paris et nous avons choisi l’Égypte car il est pertinent d'étudier comment l’amour surréaliste peut être exprimé en Égypte, malgré le fait que le conservatisme demeure la norme

Le grand tabou : l'amour surréaliste en Égypte

Dans ce mémoire, il est intéressant de faire une comparaison entre la France et l’Égypte. Nous avons choisi la France comme pays fondateur, car le surréalisme est né à Paris et nous avons choisi l’Égypte car il est pertinent d'étudier comment l’amour surréaliste peut être exprimé en Égypte, malgré le fait que le conservatisme demeure la norme

The impact of child adjustment to preschool on maternal separation anxiety

The purpose of the proposed study is to examine longitudinally how a mother's perception of her child's temperament and adjustment to preschool may mediate the relationships found in previous research between maternal separation anxiety and maternal role conflict, child care satisfaction, and job satisfaction. Approximately 110 working mothers with preschool-aged children participated in this study. In order to account for higher drop out rates that are associated with longitudinal research designs, approximately 200 mothers from various ethnic and SES backgrounds will be recruited from preschools and day care centers in the Maryland and Virginia suburbs of Washington, D.C. A participant will only be included in the sample if she is working at least 15 hours per week and has a preschool-aged child (age 2–6 years). A child can be attending no higher than a kindergarten class level to be considered a preschooler. The results of this study suggest that child temperament is significantly related to both a child's adjustment to preschool and maternal separation anxiety. However, the results of the current study suggest that a child's positive adjustment to preschool or day care does not effect the relationships between MSA at Time 1 (i.e., the beginning of the school year) and MSA at Time 2 (i.e., 4 months later), nor does it mediate MSA and role strain as measured by scales of work-family conflict, or MSA and maternal job satisfaction, nor MSA and maternal child care satisfaction. The possible implications of this research are explored

Le grand tabou : l'amour surréaliste en Égypte

Dans ce mémoire, il est intéressant de faire une comparaison entre la France et l’Égypte. Nous avons choisi la France comme pays fondateur, car le surréalisme est né à Paris et nous avons choisi l’Égypte car il est pertinent d'étudier comment l’amour surréaliste peut être exprimé en Égypte, malgré le fait que le conservatisme demeure la norme