Variabilidade temporal dos dados de temperatura do ar em Botucatu-SP.

A possibilidade de estimar a variação horária da temperatura do ar com base em poucos registros ao longo dia motivou este trabalho que visa estudar a variabilidade temporal da temperatura do ar em Botucatu-SP, a fim de obter os melhores horários para a sua estimativa

Estimativa e comparação da área ocupada por plantas aquáticas na superfície da Represa Salto Grande - SP com auxílio da classificação de imagens CBERS-2B.

This study aims to estimate, by using the NDVI index and the unsupervised classification method CLUSTER, the areas covered by aquatic plants in Salto Grande dam, Americana - SP, comparing 2008 and 2010. The NDVI is sensitive to capture the spectral response of vegetation, which has high reflectance in the near infrared band. The classification, supervised or unsupervised, of images obtained by the index of vegetation contributes to the elaboration of thematic maps. In the process of unsupervised classification, the algorithm CLUSTER was used, which is based on a composite image, to obtain satisfactory groupings. This classifier selects the pixels at the peak of the histogram. It was observed that the area mapped with aquatic plants in 2008 is more representative due to a higher volume of them, compared to 2010. With the use of images from the satellite CBERS-2B was possible to estimate the area covered by aquatic plants on the surface of Salto Grande Dam, in Americana (SP), supported by the unsupervised classification CLUSTER, obtained after NDVI process. The maps offer an opportunity to work with a better interpreting of the different targets in the study area images, supporting the monitoring of aquatic plants in the dams and other water bodies

Análise temporal de fatores climáticos em Petrolina - PE.

A determinação prévia da variação de elementos climatológicos ao longo do ano é de interesse do planejamento e de previsão de cenários na agricultura e em outros atividades

Uso da banda termal do satélite LANDSAT-5 e técnicas de geoestatística na estimativa da degradação da Atrazina no solo da Área de Proteção Ambiental de Tejupá.

Este estudo teve como objetivo avaliar a empregabilidade da banda termal do Landsat-5 e técnicas de geoestatística, para obtenção das estimativas da taxa de degradação da Atrazina na superfície do solo

Admittance spectroscopy of Cu2ZnSnS4 based thin film solar cells

In this report, we propose an AC response equivalent circuit model to describe the admittance measurements of Cu2ZnSnS4 thin film solar cell grown by sulphurization of stacked metallic precursors. This circuit describes the contact resistances, the back contact, and the heterojunction with two trap levels. The study of the back contact resistance allowed the estimation of a back contact barrier of 246 meV. The analysis of the trap series with varying temperature revealed defect activation energies of 45 meV and 113 meV. The solar cell’s electrical parameters were obtained from the J-V curve: conversion efficiency, 1.21%; fill factor, 50%; open circuit voltage, 360 mV; and short circuit current density, 6.8 mA/cm2