959 resultados para work function measurements
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Pós-graduação em Engenharia Elétrica - FEIS
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Pós-graduação em Química - IQ
Recalibration of U-doped standard glasses through uranium thin film for neutron-fluence measurements
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
There are strong uncertainties regarding LAI dynamics in forest ecosystems in response to climate change. While empirical growth & yield models (G&YMs) provide good estimations of tree growth at the stand level on a yearly to decennial scale, process-based models (PBMs) use LAI dynamics as a key variable for enabling the accurate prediction of tree growth over short time scales. Bridging the gap between PBMs and G&YMs could improve the prediction of forest growth and, therefore, carbon, water and nutrient fluxes by combining modeling approaches at the stand level.Our study aimed to estimate monthly changes of leaf area in response to climate variations from sparse measurements of foliage area and biomass. A leaf population probabilistic model (SLCD) was designed to simulate foliage renewal. The leaf population was distributed in monthly cohorts, and the total population size was limited depending on forest age and productivity. Foliage dynamics were driven by a foliation function and the probabilities ruling leaf aging or fall. Their formulation depends on the forest environment.The model was applied to three tree species growing under contrasting climates and soil types. In tropical Brazilian evergreen broadleaf eucalypt plantations, the phenology was described using 8 parameters. A multi-objective evolutionary algorithm method (MOEA) was used to fit the model parameters on litterfall and LAI data over an entire stand rotation. Field measurements from a second eucalypt stand were used to validate the model. Seasonal LAI changes were accurately rendered for both sites (R-2 = 0.898 adjustment, R-2 = 0.698 validation). Litterfall production was correctly simulated (R-2 = 0.562, R-2 = 0.4018 validation) and may be improved by using additional validation data in future work. In two French temperate deciduous forests (beech and oak), we adapted phenological sub-modules of the CASTANEA model to simulate canopy dynamics, and SLCD was validated using LAI measurements. The phenological patterns were simulated with good accuracy in the two cases studied. However, IA/max was not accurately simulated in the beech forest, and further improvement is required.Our probabilistic approach is expected to contribute to improving predictions of LAI dynamics. The model formalism is general and suitable to broadleaf forests for a large range of ecological conditions. (C) 2014 Elsevier B.V. All rights reserved.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Mirandópolis/SP appeared in 1934 from the railroad “the Brazil Northwest”, that there it served one of the points of its stretch that had as main function to drain the agricultural production northwestern native of São Paulo of that time. The installation of the town happened absent of concerns with initial urbanístico planning, thus modifying its natural landscape and modifying characteristic ambient without compensatory measures aiming at a future expansion of the urban mesh. Fact this that still causes today consequences the quality of life of the people and also the observed thermal comfort later. Ahead of this, the present work had for objective to identify through measurements of temperature and relative humidity of the city of Mirandópolis/SP the differences that in the fabric urban they corroborate for a comfort situation or thermal discomfort to the outdoors in accordance with the Diagram Bioclimático de Olgyay the collection of data was made throughout the month of July of 2011 involving the attainment of information of Temperature and relative humidity of air and questionnaire applied to the passer-bys in the act of the measurements. Also approaching the different thermal dynamic of the zones of housing in relation to the Urban Cannyon that develops the commerce as predominant activity. This research sample that, although a city to be small, the quality of life of its inhabitants is not only guaranteed by the transport or that its thermal comfort reveals inside homogeneous of the urban perimeter, but that it has yes heterogeneidade in the scope of the urban climate in these spaces
Resumo:
In this work, air dielectric barrier discharge (DBD) operating at two different frequencies (60 Hz and 17 kHz) was used to improve surface properties of polypropylene (PP). The changes in surface hydrophilicity were investigated by contact angle measurements. The modifications in chemical composition of PP surface were studied by X-ray photoelectron spectroscopy (XPS) and Fourier-transformed infrared spectroscopy (FTIR). The PP roughness were analyzed before and after the DBD treatment using atomic force microscopy (AFM). In order to compare the results obtained at different frequencies, the analyses are presented as a function of the deposited energy density. The results show that both DBD treatments led to formation of low-molecular weight oxidized material (LMWOM). It tends to agglomerate into small mounts on the surface, as shown by AFM analyses. These structures are weakly bounded to the surface and can be easily removed by rinsing in polar solvents. After washing the DBD-treated samples, the PP partially recovers its original wetting characteristics. This suggests that oxidation also occurred at deeper and more permanent levels on the PP samples. Comparing both DBD treatments, the 17 kHz process was found to be more efficient in introducing oxygen groups to the PP surface
Resumo:
In this paper we investigate the C ` versions of contact and right equivalences of real semi-quasihomogeneous C ` function germs, 1 ≤ ` ≤ ∞. The C ` -right equivalence implies C ` -contact equivalence for any 1 ≤ ` ≤ ∞ and in this work we show, up to certain conditions, that for semi-quasihomogeneous C ` function germs the converse is also true. As a consequence, we recover some known results about C∞-right and C∞-contact equivalences of C∞ function germs. We note that we are considering semi-quasihomogeneous function germs with no additional hypothesis of isolated singularity at zero.