Study of the HVDC dual transmission system under faults in the power converters

Trabalho apresentado no Speedam 2016, 22-24 de junho de 2016, Capri, ItáliaHVDC transmission systems based on voltage source converters have lately emerged as a good alternative to conventional AC transmission. In these transmission systems multilevel converters have become a promising energy conversion technology. The reliability of the power converters are extremely important since a fault in these equipments may lead to an unavailability for a long period of the transmission system. Thus, this paper will focuses in HVDC dual transmission system under semiconductor failure conditions. As presented in this paper this structure presents interesting characteristics under the point of view the reliability considering a power semiconductor failure. It will present the consequences for the transmission system when there is a semiconductor fault. A study for the change of the modulation system in order to ensure DC link capacitors voltage balance under a fault condition is also presented. Simulation studies are shown in order to confirm the characteristics of the proposed methodology in normal and fault condition mode.N/

Leadership and management in the schools of the Autonomous Region of Madeira: A case study

Este estudo de investigação, de caracter misto, consistiu na aplicação de um inquérito a 504 professores e a realização de 19 entrevistas semiestruturadas (dezoito a Diretores/Presidentes das instituições escolares, e uma ao Diretor Regional da Administração Educativa). Foi nosso objetivo fazer uma análise sobre o tema da organização, gestão e liderança escolar dos Diretores/Presidentes das escolas do segundo e terceiros Ciclos do Ensino Básico e do Ensino Secundário da Região Autónoma da Madeira (RAM). Neste artigo iremos focar-nos nos resultados qualitativos resultantes da investigação. Os resultados do estudo revelaram que: os professores continuam a preocupar-se com a transmissão dos valores fundamentais e alcance do sucesso educativo numa escola em crise; que o estilo de liderança predominantemente adotado pelos Diretores/Presidentes das escolas da RAM é o estilo transformacional; que o exercício do gestor/líder obedece a um perfil enquadrado num modelo de Diretor/Presidente padrão com caraterísticas bem determinadas.This research, mixed in nature, deals with the application of a questionnaire to 504 teachers and the performance of 19 semi structured interviews (18 to school Head teachers and one to the Regional Educational Administration Director). It was our objective to do an analysis on the subject of organization, school management and leadership of the Directors / Presidents of the second and third of the schools of basic education cycles and Secondary Education of the Autonomous Region of Madeira (RAM). In this article we will focus on the qualitative results derived from the research study. The results of this study reveal that: the teachers are still worrying about the transmission of fundamental values and the reach of the educational success within a school in crisis; the predominant style of leadership adopted by Head teachers in RAM is the “transformational” style; the manager/leader performance follows a pattern of well-defined characteristics.info:eu-repo/semantics/publishedVersio

Coupling of Cyclic Voltammetry and Electrochemical Impedance Spectroscopy for Probing the Thermodynamics of Facilitated Ion Transfer Reactions Exhibiting Chemical Kinetic Hindrances

Mathematical models under conditions of cyclic staircase voltammetry and electrochemical impedance spectroscopy (EIS), which consider the kinetic effects due to the complexation reaction by the facilitated transfer of metal ions at polarized interfaces, are presented. Criteria for qualitative recognition of these kinetic effects from the features of simulated cyclic voltammograms are given. In case of the existence of these effects, only the EIS can bring access to the thermodynamics and kinetics of the complexation chemical reaction. Analytical equations for estimating the thermodynamic parameters by such systems under EIS conditions are evaluated. The theoretical results are compared with the experimental results of the facilitated Cu2+ transfer at the polarized water-1,2-dichlorethane interface, assisted by two phenanthroline-containing macrocycles. In the experimental case where kinetic effects due to the complexation step exist, we show how elegantly EIS can be used as a tool for estimation of the complexation constant of Cu2+ and 5-oxo-2,8-dithia [9],(2,9)-1,10-phenanthrolinophane (PhenOS2)

Characterization of a free air ionization chamber for low energies

Resumo: As câmaras de ionização de ar livre são usadas pela maioria dos laboratórios primários como padrões primários das grandezas kerma no ar e exposição em feixes de raios X. A câmara de ionização de ar livre para baixas energias do Laboratório de Calibração (LCI) do IPEN mostrou em um teste de caracterização um problema no conjunto responsável pela variação do seu volume sensível. Depois de uma modificação no suporte dos micrômetros usados para o movimento do cilindro interno e do estabelecimento de um novo protocolo de sistema de alinhamento, os testes foram refeitos. O objetivo deste trabalho é apresentar os resultados obtidos na nova condição. Palavras-chave: câmara de ionização de ar livre, testes de caracterização, baixas energias Abstract: Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition

Methylene blue associated with maghemite nanoparticles has antitumor activity in breast and ovarian carcinoma cell lines

Background: Cancer constitutes group of diseases responsible for the second largest cause of global death, and it is currently considered one of the main public health concerns nowadays. Early diagnosis associated with the best choice of therapeutic strategy, is essential to achieve success in cancer treatment. In women, breast cancer is the second most common type, whereas ovarian cancer has the highest lethality when compared to other neoplasms of the female genital system. The present work, therefore, proposes the association of methylene blue with citrate-coated maghemite nanoparticles (MAGCIT–MB) as a nanocomplex for the treatment of breast and ovarian cancer. Results: In vitro studies showed that T-47D and A2780 cancer cell lines underwent a significant reduction in cell viability after treatment with MAGCIT–MB, an event not observed in non-tumor (HNTMC and HUVEC) cells and MDA-MB-231, a triple-negative breast cancer cell line. Flow cytometry experiments suggest that the main mechanism of endocytosis involved in the interiorization of MAGCIT–MB is the clathrin pathway, whereas both late apoptosis and necrosis are the main types of cell death caused by the nanocomplex. Scanning electron microscopy and light microscopy reveal significant changes in the cell morphology. Quantification of reactive oxygen species confirmed the MAGCIT–MB cytotoxic mechanism and its importance for the treatment of tumor cells. The lower cytotoxicity of individual solution of maghemite nanoparticles with citrate (MAGCIT) and free methylene blue (MB) shows that their association in the nanocomplex is responsible for its enhanced therapeutic potential in the treatment of breast and ovarian cancer in vitro. Conclusions: Treatment with MAGCIT–MB induces the death of cancer cells but not normal cells. These results highlight the importance of the maghemite core for drug delivery and for increasing methylene blue activity, aiming at the treatment of breast and ovarian cancer

Associations of physical activity and sedentary time with body composition in Brazilian young adults.

The findings of studies on the association between physical activity and adiposity are not consistent, and most are cross-sectional and used only self-reported measures. The aims of this study were to evaluate: 1) independent and combined cross-sectional associations of objectively-measured physical activity and sedentary time with body composition outcomes at 30 years, and 2) prospective associations of changes in self-reported physical activity from 23 to 30 years with the same outcomes in participants from the 1982 Pelotas (Brazil) Birth Cohort. Body mass index, waist circumference, visceral abdominal fat, fat mass index, and android/gynoid fat ratio were the outcomes. 3,206 participants were analysed. In cross-sectional analyses, higher objectively-measured moderate-to-vigorous physical activity was associated with lower body mass index (β = 0.017, 95%CI: -0.026; -0.009), waist circumference (β = -0.043, 95%CI: -0.061; -0.025), visceral abdominal fat (β = -0.006, 95%CI: -0.009; -0.003), and fat mass index (β = -0.015, 95%CI: -0.021; -0.009), independent of sedentary time. Sedentary time was independently associated only with higher fat mass index (β = 0.003, 95%CI: 0.001; 0.005). In longitudinal analyses, using self-reported measure, adiposity was lower among those who were consistently active or who became active. Adiposity was similar among the "became inactive" and "consistently inactive" subjects. Our findings suggest metabolic benefits from engagement in physical activity throughout young adulthood, with stronger associations on concurrent levels.SB, KKO and EDLR are supported by the Medical Research Council (Unit Programme numbers: MC_UU_12015/2 and MC_ UU_12015/4)

Demystifying molecular biology and functional foods

Resumo do Congresso de Graduação da USP 2021

Proteinuria Is Associated with Quality of Life and Depression in Adults with Primary Glomerulopathy and Preserved Renal Function

BACKGROUND: There is no information about HRQoL, depression and associated factors in adult with nephrotic syndrome-associated glomerulopathy. METHODOLOGY/PRINCIPAL FINDINGS: Patients with primary glomerulopathy where compared with age and sex-matched hemodialysis patients and healthy subjects. Laboratory data, medical history, comorbid conditions were collected to evaluate factors associated with HRQoL (SF-36) and Depression (Hamilton Depression Rating Scale-HAMD). Glomerulopathy patients had low HRQoL in all eight SF-36 domains and two composite scores (physical and mental) in comparison with healthy subjects. HAMD score also was elevated and there was high depression prevalence. Overall, these data were comparable between glomerulopathy and hemodialysis patients. Using multiple regression analysis, factors associated with low HRQoL physical composite score were: last 24 h-urine protein excretion (-0.183, 95%CI -0.223 to -0.710 for each gram of proteinuria, p = 0.01) and cyclosporine use (-15.315, 95%CI -25.913 to -2.717, p = 0.03). Low HRQoL mental composite score was associated with last 24 h-urine protein excretion (-0.157, 95%CI -0.278 to -0.310 for each gram of proteinuria, p = 0.03) and HMAD score was independently associated with age (0.155, 95%CI 0.318 to 0.988 for each year, p = 0.04), female sex (4.788, 95%CI 1.005 to 8.620, 0 = 0.03), disease duration (0.074, 95%CI 0.021 to 0.128 for each month, p = 0.01) and last 24 h-urine protein excretion (0.050, 95%CI 0.018 to 0.085 for each gram of proteinuria, p = 0.02). CONCLUSIONS/SIGNIFICANCE: Nephrotic-syndrome associated glomerulopathy patients have low HRQoL and high prevalence of depression symptoms, comparable with those of hemodialysis patients. Last 24 h-protein excretion rate is independently associated with physical and mental HRQoL domains in addition to depression