Extended description of tunnel junctions for distributed modeling of concentrator multi-junction solar cells

One of the key components of highly efficient multi-junction concentrator solar cells is the tunnel junction interconnection. In this paper, an improved 3D distributed model is presented that considers real operation regimes in a tunnel junction. This advanced model is able to accurately simulate the operation of the solar cell at high concentraions at which the photogenerated current surpasses the peak current of the tunnel junctionl Simulations of dual-junction solar cells were carried out with the improved model to illustrate its capabilities and the results have been correlated with experimental data reported in the literature. These simulations show that under certain circumstances, the solar cells short circuit current may be slightly higher than the tunnel junction peak current without showing the characteristic dip in the J-V curve. This behavior is caused by the lateral current spreading toward dark regions, which occurs through the anode/p-barrier of the tunnel junction

Simulação do impacto das atividades florestais na fragilidade potencial em plantios de pinus.

Este trabalho, realizado em uma área com povoamento de Pinus taeda, teve por objetivo simular e mapear a influência do valor de impacto das atividades florestais na fragilidade potencial. Variáveis do solo, de declividade do terreno, valor de impacto e de cobertura vegetal foram utilizadas para gerar os mapas. Os resultados expressos pelo modelo adotado mostraram que as áreas mais frágeis apresentam em sua maioria declividades superiores a 75 % e textura que variam de arenosa a média, e as áreas menos frágeis apresentam predominantemente relevo plano (até 3 %) e textura argilosa. Quando simulado o impacto das atividades florestais sobre esse ambiente, verificou-se que na maior parte da área (78 %) todas as atividades florestais podem ser realizadas sem influência na degradação do meio ambiente e para algumas áreas (11 %) o ambiente foi considerado menos frágil, em razão da presença de cobertura vegetal

Unidades de manejo para Pinus taeda L. com base na análise de agrupamento.

Seção: Silvicultura e Produção de Biomassa

Geomagnetic data from the GOCE satellite mission

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) is part of ESA’s Earth Explorer Program. The satellite carries magnetometers that control the activity of magnetorquers for navigation of the satellite, but are not dedicated as science instruments. However, intrinsic steady states of the instruments can be corrected by alignment and calibration, and artificial perturbations, e.g. from currents, can be removed by their characterisation correlated to housekeeping data. The leftover field then shows the natural evolution and variability of the Earth’s magnetic field. This article describes the pre-processing of input data as well as calibration and characterisation steps performed on GOCE magnetic data, using a high-precision magnetic field model as reference. For geomagnetic quiet times, the standard deviation of the residual is below 13 nT with a median residual of (11.7, 9.6, 10.4) nT for the three magnetic field components (x, y, z). For validation of the calibration and characterisation performance, we selected a geomagnetic storm event in March 2013. GOCE magnetic field data show good agreement with results from a ground magnetic observation network. The GOCE mission overlaps with the dedicated magnetic field satellite mission CHAMP for a short time at the beginning of 2010, but does not overlap with the Swarm mission or any other mission flying at low altitude and carrying high-precision magnetometers. We expect calibrated GOCE magnetic field data to be useful for lithospheric modelling and filling the gap between the dedicated geomagnetic missions CHAMP and Swarm. Graphic Abstract: [Figure not available: see fulltext.]

Reflectance anisotropy spectroscopy assessment of the MOVPE nucleation of GaInP on Germanium (100)

This work summarizes the observations made on the variation and time evolution of the reflectanceanisotropy signal during the MOVPE growth of GaInPnucleation layers on Germanium substrates. This in situ monitoring tool is used to assess the impact of different nucleation routines and reactor conditions on the quality of the layers grown. This comparison is carried out by establishing a correlation between reflectanceanisotropy signature at 2.1 eV and the morphology of the epilayers evaluated by atomic force microscopy (AFM). This paper outlines the potential of reflectanceanisotropy to predict, explore, and therefore optimize, the best growth conditions that lead to a high quality III–V epilayer on a Ge substrat

Levantamento detalhado de solos de áreas de produção florestal no Município de Ponte Serrada, oeste catarinense.

Introdução; Material; Levantamento de solos; Metodologia de trabalho; Resultados do mapeamento de solos; Legenda do mapeamento de solos; Classes de solo (definidas conforme Embrapa, 2006); Latossolos Brunos (LB); Nitossolos Brunos (LB); Cambissolos Húmicos (CH); Neossolos Litólicos (RL), Neossolos Regolíticos (RR) e afloramentos de rocha (AR); Gleissolos Melânicos; Considerações finais; Referências; Anexo - mapa detalhado de solo da Fazenda Cristo Rei, Celulose Irani S.A.bitstream/item/121209/1/Doc.-249-Joao-Bosco-versao-final.pd