Silicone insulators of power transmission lines with a variable inorganic load concentration: Electrical and physiochemical analyses

Polymeric insulation is an increasing tendency in projects and maintenance of electrical networks for power distribution and transmission. Electrical power devices (e. g., insulators and surge arresters) developed by using polymeric insulation presents many advantages compared to the prior power components using ceramic insulation, such as: a better performance under high pollution environment; high hydrophobicity; high resistance to mechanical, electrical and chemical stresses. The practice with silicone insulators in polluted environments has shown that the ideal performance is directly related to insulator design and polymer formulation. One of the most common misunderstandings in the design of silicone compounds for insulators is the amount of inorganic load used in their formulation. This paper attempts to clarify how the variation of the inorganic load amount affects physicochemical characteristics of different silicone compounds. The physicochemical evaluation is performed from several measurements, such as: density, hardness, elongation, tensile strength. In addition, the evaluation of the physicochemical structure is carried out using infrared test and scanning electronic microscopy (SEM). The electrical analysis is performed from the electric tracking wheel and erosion test, in agreement with the recommendation of the International Electrotechnical Commission (IEC). (C) 2014 Elsevier Ltd. All rights reserved.

Estimating the concentration of gold nanoparticles incorporated on natural rubber membranes using multi-level starlet optimal segmentation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rheological behavior of Peruvian carrot starch gels as affected by temperature and concentration

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Increased atmospheric carbon dioxide concentration: effects on eucalypt rust (Puccinia psidii), C:N ratio and essential oils in eucalypt clonal plantlets

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of the concentration of phenothiazine photosensitizers in antimicrobial photodynamic therapy on bone loss and the immune inflammatory response of induced periodontitis in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tumescent local anesthesia with ropivacaine in different concentrations in bitches undergoing mastectomy: plasma concentration and post-operative analgesia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Erythrocyte selenium concentration predicts intensive care unit and hospital mortality in patients with septic shock: a prospective observational study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of dietary energy concentration on performance parameters and egg quality of white leghorn laying hens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of caffeine on larval mortality of Aedes aegypti: efficiency related to solution concentration and age

In two experiments, the duration of the effect of caffeine (CAF) solutions on larval mortality (LM) of Aedes aegypti was analyzed. In the first, LM was studied using solutions at 0.2, 0.5, 1.0 and 2.0 mg/mL aged from zero to five days in artificial breeding sites exposed to the laboratory environment (LE). In the second, the solutions aged at 1.0, 2.0 and 2.5 mg/mL closed flasks were stored in LE or in the refrigerator (R), and the effect on LM was tested in the experimental breeding sites at 30 days interval. In the first, the duration of the effect increased with the solution age in each CAF concentration. CAF at 1.0 and 2.0 mg/mL, without addition of food, produced 100% LM until 25 days after preparation; with food, at 11 and 18 days, respectively. In the second the effectiveness of CAF solutions lasted up to the seventh month, irrespective of whether they were stored in R or in LE. No adult emerged at any of the CAF concentrations used in second experiment.

Imagens de satélite na análise da relação entre queimadas, aerossóis atmosféricos e precipitação

The direct and indirect effects of atmospheric aerossols in the amazonic climate have been focus of many published. This work aims to analyze a possible relation among Burns, atmospheric aerossols and precipitation above South America. It uses the avaluable data from the satellites AQUA/TERRA and TRMM and the images furnished by NOAA and GOES. These analysis can provide some explanations about the effects of emission of aerosols by burns on the composition of atmosphere and cloud formation, mainly in Amazon. We use the Aerosol Optical Depth (AOD) from MODIS/TERRA-AQUA, burns index from CPTEC and rain rate from TRMM. The data we use were obtained from 2000 until 2012. The study is divided in two parts. In the first one, it was performed a quantitative analysis between number of burns and aerosols emission. It was identified a great variability in space and time of the AOD on South America. On the north, northeast and center-west, the AOD is significant during the winter period, with peak on August and September. The southeast is affected by aerosols from center-west due to the dynamical transport. In the second part, it was evaluated the relation between AOD and precipitation in a 13-year period. The statistical analysis shows up a negative correlation of 0.72 between August and October, on Legal Amazon. These result indicate an inverse relation between AOD and rain rate. The other months present not significant correlation. These results are in a good agreement with the literature, in which in-situ methods were applied or combined with satellites data. The increasing of aerosols concentration in the atmosphere are reinforced during drier years. It can affect the increasing process of water drops, decreasing the precipitation. We also verified higher values of AOD (0.25 - 0.3) during years with El Niño, than the climatologically average (~0.15 - 0.2), ... (Complete abstract click electronic access below)

Influence of the concentration of Sb2O3 on the electrical properties of SnO2 varistors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

"Will It Rain?" Activities Investigating Aerosol Hygroscopicity and Deliquescence

Climate change and its consequences seem to be increasingly evident in our daily lives. However, is it possible for students to identify a relationship between these large-scale events and the chemistry taught in the classroom? The aim of the present work is to demonstrate that chemistry can assist in elucidating important environmental issues. Simple experiments are used to demonstrate the mechanism of cloud formation, as well as the influence of anthropogenic and natural emissions on the precipitation process. The experiments presented show the way in which particles of soluble salts commonly found in the environment can absorb water in the atmosphere and influence cloud formation.

Análise espacial e temporal da precipitação, do material particulado e da radiação global em municípios paulistas

Pós-graduação em Engenharia Mecânica - FEG