Methods for a systematic analysis of power converters

This contribution aims at presenting fundamental principles and theoretical tools for a comprehensive study and systematic analysis of generic power conversion circuits. The contents are divided into three main parts. Part I presents a new graphical technique for the state analysis of the so-called ‘fundamental LCEI type circuit’, which is found in sequences of many practical power converter topologies. In Part II, this graphical technique is used within a straightforward sequence-by-sequence algorithm to study the intrinsic functionality of power converters and to describe the evolution in time of their main quantities (state variables) and the conditions governing switch commutations and state transitions. Part III is devoted to power converter modelling techniques, a major advance for stable control loop design

Contribuição ao conhecimento da flora de leguminosae da Reserva Florestal do Moju, município de Moju, Estado do Pará.

bitstream/item/57336/1/CPATU-PA169.pdfResumos publicados em Reunião dos Botânicos da Amazônia, 2., 1997, Salinopólis, PA. p. 17 e Seminário de Iniciação Científica da FCAP, 7.; Seminário de Iniciação Científica da Embrapa Amazônia Oriental, 1., 1997, Belém, PA. p. 148

Desinfestação de segmentos nodais de Eucalyptus dunnii visando estabelecimento in vitro.

A espécie Eucalyptus dunnii apresenta potencial econômico e técnico de exploração na metade sul do Rio Grande do Sul. Esta espécie tem como característica produzir poucas sementes, o que dificulta sua propagação. A cultura de tecidos oferece grande potencial para a propagação in vitro de espécies lenhosas. A micropropagação só pode ocorrer se o processo de desinfestação obtiver sucesso. O objetivo deste trabalho foi avaliar e adequar o processo de desinfestação de segmentos nodais pertencentes à espécie Eucalyptus dunnii. Foram realizados tratamentos com hipoclorito de sódio (NaClO) á 0%; 0,5%; 1,0%; 1,5% e 2,0% de cloro ativo. As avaliações nos tratamentos foram em relação as contaminações fúngicas e bacterianas; oxidações; sobrevivência e o estabelecimento dos explantes. Observou-se que não houve diferença significativa entre os tratamentos, porém, os níveis de contaminações diminuíram quando submetidos nas diferentes variações de concentração de (NaClO) em relação ao tratamento testemunha. Pode-se verificar que os explantes submetidos nas concentrações de 1,5% e 2,0% de (NaClO), obtiveram melhores resultados quando comparados aos demais tratamentos

Histologic and Histomorphometric Analysis of Posterior Region of the Human Temporomandibular Disc

Objective The aim of this study was to analyze histologic and histomorphometric features of the articular disc in groups with and without disc displacement. Study design A sample of 39 temporomandibular joints TMJs (31 case specimens, 8 control specimens) from 28 patients (mean age 31.2 years) were recruited for this study. The patients were considered to be affected and treated surgically with disc repositioning when presenting painful clinical signs of disc displacement after unsuccessful nonsurgical treatment for at least 6 months. Of the control patients, 4 presented condyle fracture which required opening to be reduced for treatment, and 4 displayed active condyle hyperplasia. The posterior region of the disc was removed and sent for histologic and histomorphometric analysis. Histologic (hematoxylin-eosin) and histomorphometric (picro-Sirius red) analyses were performed. Statistically significant differences between the analyzed groups were accessed through the chi-squared test (P ≤ .05). The Mann-Whitney U test was used to observe the differences between mean values when variables did not present normal distribution [Kolmogorov-Smirnov(a) test]. Results There were no significant differences between the groups in relation to the parameters studied by histologic and histomorphometric analysis (using or not using polarization). Conclusions To the limits of this study, there were no significant histologic and histomorphometric differences in the articular disc between groups with and without TMJ dysfunction

Organomineral phosphorus fertilization in the production of corn, soybean and bean cultivated in succession.

The use of organic waste in agriculture has been used aiming at greater productivity, decrease in the cost of production and sustainable use of resources. The present study aimed at evaluating the effect of phosphate fertilization with the maintenance of organomineral fertilizers, combining poultry manure and soluble or reactive phosphate, in the production of grains in corn culture and the residual effect for subsequent crops of beans and soybeans. The experiment was conducted in Sete Lagoas, MG, in 2015, using three fertilizers with sources of different phosphorus sources (triple super phosphate?STP, organomineral with STP and organomineral with Bayovar phosphate) applied at the doses of 65, 130, 195 and 260 kg∙ha−1 of P2O5 total, and compared to the control without phosphate fertilization. We evaluated the contents of foliar P, P accumulation in the grains, yields of corn grains, beans and soy, accumulated productivity and export of accumulated P of the three cultures. The three cultures assessed presented higher productivity when compared to the average of the factorial treatments that received phosphate fertilization relative to the control. Organomineral fertilizers increased grain production, obtaining average productivity equal to or greater than those obtained with the exclusive use of STP

Analysis of Visible/SWIR surface reflectance ratios for aerosol retrievals from satellite in Mexico City urban area

International audienceThe surface reflectance ratio between the visible (VIS) and shortwave infrared (SWIR) radiation is an important quantity for the retrieval of the aerosol optical depth (?a) from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS ?a retrieval uses the surface reflectance in the SWIR band (2.1 µm), where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 µm) and red (0.66 µm) bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA) using MODIS radiances at 0.66 µm and 2.1 µm. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol depth and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of ?a in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06 for scattering angles a averaged from sun-photometer measurements. The use of the new RED/SWIR ratio of 0.73 in the MODIS retrieval over Mexico City led to a significant improvement in the agreement between the MODIS and sun-photometer AOD results; with the slope, offset, and the correlation coefficient of the linear regression changing from (?aMODIS=0.91?a sun-photometer+0.33, R2=0.66) to (?aMODIS=0.96 ?a sun-photometer?0.006, R2=0.87). Indeed, an underestimation of this ratio in urban areas lead to a significant overestimation of the AOD retrieved from satellite. Therefore, we strongly encourage similar analyses in other urban areas to enhance the development of a parameterization of the surface ratios accounting for urban heterogeneities

Urban Visible/SWIR surface reflectance ratios from satellite and sun photometer measurements in Mexico City

International audienceThe surface reflectance ratio between the visible (VIS) and shortwave infrared (SWIR) radiation is an important quantity for the retrieval of the aerosol optical depth (?a) from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS ?a retrieval uses the surface reflectance in the SWIR band (2.1 ?m), where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 ?m) and red (0.66 ?m) bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. The heterogeneity of the surface cover in an urban environment increases the uncertainties in the estimation of the surface reflectance and, consequently, ?a. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA) using MODIS radiances at 0.66 ?m and 2.1 ?m. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol optical thickness and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of ?a in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06. This average ratio was significantly different for non-urban sites, which was approximately 0.55. The aerosol optical thickness retrieved from MODIS radiances at a spatial resolution of 1.5 km×1.5 km and averaged within 10 x 10 km boxes were compared with collocated 1-h ?a averaged from sun-photometer measurements. The use of the new RED/SWIR ratio of 0.73 in the MODIS retrieval led to a significant improvement in the agreement between the MODIS and sun-photometer results; with the slope, offset, and the correlation coefficient of the linear regression changing from (?aMODIS = 0.91 ?a sun-photometer + 0.33 ,R2=0.66) to (?aMODIS = 0.96 ?a sun-photometer ?0.006, R2=0.87)