Aplicació de calculadora solar

El present treball fi de carrera consisteix en la realització de l'estudi, disseny i implementació d'una aplicació informàtica dins de la temàtica dels sistemes d'informació geogràfica (SIG) per realitzar el càlcul de la quantitat de llum solar rebuda pels diferents edificis d'una ciutat. L'aplicació s'ha desenvolupat sota l'entorn de GeoMedia, una plataforma comercial per tractar dades SIG, i ha estat programada en Visual Basic fent servir l'entorn Visual Studio 2012.

Aplicació de calculadora solar

Implantació d'una calculadora de radiació solar sobre els edificis d'una zona d'estudi.

Decomposição de amostras de solos assistida por radiação microondas: estratégia para evitar a formação de fluoretos insolúveis

A decomposição de amostras que contêm elevados teores de Si, utilizando mistura com os ácidos nítrico e fluorídrico, pode provocar a precipitação de fluoretos de Al(III), Ca(II), Fe(III) e Mg(II) durante a digestão, impedindo a recuperação total desses elementos. Visando minimizar esse problema, foram testados quatro procedimentos aplicados a diferentes amostras de solos. O procedimento mais eficiente envolveu a decomposição assistida por radiação microondas, seguida pela separação do material sólido residual com elevado teor de Si do sobrenadante ácido. A fração residual foi solubilizada usando HF concentrado e, após complexação com ácido bórico, essa solução foi misturada à fase líquida do digerido. Os teores de metais nos digeridos foram determinados por espectrometria de emissão óptica em plasma induzido (ICP OES) e a exatidão foi demonstrada aplicando o procedimento proposto em amostras provenientes do programa colaborativo International Soil-Analytical Exchange (ISE, Wegening Agricultural University, Holanda) e em amostra certificada de solo proveniente do National Institute of Standard and Technology (NIST, SRM 2709), que apresentou respectivamente, os seguintes percentuais de recuperação: 100,0 ± 2,6; 99,5 ± 1,9; 108,5 ± 2,7; 94,6 ± 8,9; 92,2 ± 9,7; 95,7 ± 1,8; 96,7 ± 2,7; 95,2 ± 0,6; 103,6 ± 2,6 e 96,1 ± 1,6 para, Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, V e Zn.

Seasonal dependence in the solar neutrino flux

Mikheyev-Smirnov-Wolfenstein (MSW) solutions of the solar neutrino problem predict a seasonal dependence of the zenith angle distribution of the event rates, due to the nonzero latitude at the Super-Kamiokande site. We calculate this seasonal dependence and compare it with the expectations in the no-oscillation case as well as just-so scenario, in the light of the latest Super-Kamiokande 708-day data. The seasonal dependence can be sizable in the large mixing angle MSW solution and would be correlated with the day-night effect. This may be used to discriminate between MSW and just-so scenarios and should be taken into account in refined fits of the data.

Zenith angle distributions at Super-Kamiokande and SNO and the solution of the solar neutrino problem

We have performed a detailed study of the zenith angle dependence of the regeneration factor and distributions of events at SNO and SK for different solutions of the solar neutrino problem. In particular, we discuss the oscillatory behavior and the synchronization effect in the distribution for the LMA solution, the parametric peak for the LOW solution, etc. A physical interpretation of the effects is given. We suggest a new binning of events which emphasizes the distinctive features of the zenith angle distributions for the different solutions. We also find the correlations between the integrated day-night asymmetry and the rates of events in different zenith angle bins. The study of these correlations strengthens the identification power of the analysis.

Analysis of the role of mobility-lifetime products in the performance of amorphous silicon p-i-n solar cells

An analytical model of an amorphous silicon p-i-n solar cell is presented to describe its photovoltaic behavior under short-circuit conditions. It has been developed from the analysis of numerical simulation results. These results reproduce the experimental illumination dependence of short-circuit resistance, which is the reciprocal slope of the I(V) curve at the short-circuit point. The recombination rate profiles show that recombination in the regions of charged defects near the p-i and i-n interfaces should not be overlooked. Based on the interpretation of the numerical solutions, we deduce analytical expressions for the recombination current and short-circuit resistance. These expressions are given as a function of an effective ¿¿ product, which depends on the intensity of illumination. We also study the effect of surface recombination with simple expressions that describe its influence on current loss and short-circuit resistance.

Contribution of Topography and Incident Solar Radiation to Variation of Soil and Plant Litter at an Area with Heterogeneous Terrain

Natural processes that determine soil and plant litter properties are controlled by multiple factors. However, little attention has been given to distinguishing the effects of environmental factors from the effects of spatial structure of the area on the distribution of soil and litter properties in tropical ecosystems covering heterogeneous topographies. The aim of this study was to assess patterns of soil and litter variation in a tropical area that intercepts different levels of solar radiation throughout the year since its topography has slopes predominantly facing opposing geographic directions. Soil data (pH, C, N, P, H+Al, Ca, Mg, K, Al, Na, sand, and silt) and plant litter data (N, K, Ca, P, and Mg) were gathered together with the geographic coordinates (to model the spatial structure) of 40 sampling units established at two sites composed of slopes predominantly facing northwest and southeast (20 units each). Soil and litter chemical properties varied more among slopes within similar geographic orientations than between the slopes facing opposing directions. Both the incident solar radiation and the spatial structure of the area were relevant in explaining the patterns detected in variation of soil and plant litter. Individual contributions of incident solar radiation to explain the variation in the properties evaluated suggested that this and other environmental factors may play a particularly relevant role in determining soil and plant litter distribution in tropical areas with heterogeneous topography. Furthermore, this study corroborates that the spatial structure of the area also plays an important role in the distribution of soil and litter within this type of landscape, which appears to be consistent with the action of water movement mechanisms in such areas.