Noncommutative Derivation of the Planck's Radiation Law

The Planck's radiation law for the blackbody radiation spectrum was capable to explain the experimentally-measured blackbody spectrum. In order to get this result, Planck proposed his radiation law in a two-fold way: 1) by an \textit{ad hoc} modification of the assumed connection between energy and entropy for thermal radiation; 2) by assuming that the calculation of the entropy of an oscillator in thermal equilibrium with radiation is carried out by discrete units of energy. As a consequence, the energy quantization, linear in frequency, was thus introduced into physics. However, the energy quantization of the simple harmonic oscillator was originally postulated by Planck in an incomplete way, i.e., the ground state energy was not assumed to be null. Of course, this issue has been solved in different ways over time. Despite of this, we propose an alternative way to fix this issue by describing harmonic oscillators at noncommutative(NC) framework, where the non-null ground state energy naturally arises as a NC contribution. With this approach, the Planck's quantum theory is updated and, consequently, becomes compatible with the quantum mechanics inaugurated in 1925

Model for erosion-deposition patterns

We investigate through computational simulations with a pore network model the formation of patterns caused by erosion-deposition mechanisms. In this model, the geometry of the pore space changes dynamically as a consequence of the coupling between the fluid flow and the movement of particles due to local drag forces. Our results for this irreversible process show that the model is capable to reproduce typical natural patterns caused by well known erosion processes. Moreover, we observe that, within a certain range of porosity values, the grains form clusters that are tilted with respect to the horizontal with a characteristic angle. We compare our results to recent experiments for granular material in flowing water and show that they present a satisfactory agreement.Comment: 8 pages, 12 figures, submitted to Phys. Rev.

Panorama sócio-ambiental do enotorno da central Geradora Termelétrica Fortaleza (CGTF) município de Caucaia - CE.

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POSSIBILIDADES E LIMITES NA GESTÃO DA ÁGUA EM SITUAÇÃO DE ESCASSEZ : PRÁTICAS DE PRODUTORES AGRÍCOLAS NA BACIA DO PAJEÚ – PERNAMBUCO

Situada nas mesorregiões do Sertão Pernambucano e do São Francisco Pernambucano, a bacia do rio Pajeú tem clima semiárido, com médias pluviométricas anuais inferiores a 800 mm, concentradas nos meses de fevereiro, março e abril, e apresenta deficiência hídrica de nove meses. Na área da bacia a atividade econômica predominante é a pecuária, seguida da agricultura desenvolvida predominantemente por pequenos proprietários e agricultores familiares para a sua subsistência, que torna-se limitada pelo fator escassez hídrica. A produção agrícola é comprometida e reduzida em função da baixa disponibilidade hídrica e ausência de políticas efetivas para a mudança do quadro de pobreza instalado na região onde falta de acesso a água permanece sendo a grande mazela da população do semiárido, sendo a boa gestão da água essencial para a elevação da qualidade de vida local. Na porção setentrional da bacia, a ação do Projeto Dom Helder Câmara, acordo de empréstimo entre o Governo Brasileiro/Ministério do Desenvolvimento Agrário e o Fundo Internacional para o Desenvolvimento Agrário/FIDA, tem apontado na direção das possibilidades de produção agrícola e convivência com as condições de semiaridez, direcionando ações como a instalação técnicas simples de captação de água - cisternas, cisternas calçadão, barragem subterrânea. Portanto, este trabalho tem como objetivo verificar na área de atuação do projeto Dom Helder, na porção norte da bacia do Pajeú como os agricultores familiares tem viabilizado a produção agrícola inclusive com diversidade de produção de subsistência em função da instalação de técnicas de captação e armazenamento

Uso e cobertura das terras da área do entorno do reservatório da Usina Hidrelétrica de Tombos, no Estado de Minas Gerais.

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Instruções técnicas para o cultivo da gravioleira.

A graviola (Annona muricata L.) e uma fruteira tropical, ... Exigências edafoclimáticas ...Instalação do pomar.bitstream/CNPAT-2010/5378/1/It-002.pd

Soil quality indicators in a rhodic kandiudult under different uses in northern Parana, Brazil.

Sustainable use of soil, maintaining or improving its quality, is one of the goals of diversification in farmlands. From this point of view, bioindicators associated with C, N and P cycling can be used in assessments of land-use effects on soil quality. The aim of this study was to investigate chemical, microbiological and biochemical properties of soil associated with C, N and P under different land uses in a farm property with diversified activity in northern Parana, Brazil. Seven areas under different land uses were assessed: fragment of native Atlantic Forest; growing of peach-palm (Bactrys gasipaes); sugarcane ratoon (Saccharum officinarum) recently harvested, under renewal; growing of coffee (Coffea arabica) intercropped with tree species; recent reforestation (1 year) with native tree species, previously under annual crops; annual crops under no-tillage, rye (Cecale cereale); secondary forest, regenerated after abandonment (for 20 years) of an avocado (Persea americana) orchard. The soil under coffee, recent reforestation and secondary forest showed higher concentrations of organic carbon, but microbial biomass and enzyme activities were higher in soils under native forest and secondary forest, which also showed the lowest metabolic coefficient, followed by the peach-palm area. The lowest content of water-dispersible clay was found in the soil under native forest, differing from soils under sugarcane and secondary forest. Soil cover and soil use affected total organic C contents and soil enzyme and microbial activities, such that more intensive agricultural uses had deeper impacts on the indicators assessed. Calculation of the mean soil quality index showed that the secondary forest was closest to the fragment of native forest, followed by the peach-palm area, coffee-growing area, annual crop area, the area of recent reforestation and the sugarcane ratoon area