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Search Results: 1 - 10 of 6268 matches for " Jadir Aparecido;Leite "
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Determina??o da humifica??o da matéria organica de um latossolo e de suas fra??es organo-minerais
Favoretto, Célia Mara;Gon?alves, Daniele;Milori, Débora M. B. P.;Rosa, Jadir Aparecido;Leite, Wellington Claiton;Brinatti, André Maurício;Saab, Sérgio da Costa;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000800015
Abstract: laser-induced fluorescence spectroscopy was used to determine the humification degree of the organic matter of a whole soil, that is, soil without any physical or chemical treatment. particle size was determined in physically separated fractions. the humification of organic matter, the depth of the soil and the planting system can be correlated. on the surface of the soil, no tillage provided the smallest humification in comparison with the conventional tillage and reduced tillage. the fractions of the superficial layer of the soil (0-20 cm) indicated larger humification in the fraction from 20 to 53 μm and the smallest in the fraction of <2 μm.
Mineralogia de um latossolo vermelho distrófico submetido a diferentes manejos por 24 anos
Gon?alves, Daniele;Leite, Wellington Claiton;Brinatti, André Maurício;Saab, Sérgio da Costa;Iarosz, Kelly Cristiane;Mascarenhas, Yvone Primerano;Carneiro, Paulo Irajara Borba;Rosa, Jadir Aparecido;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000700006
Abstract: the search for management systems that preserve or improve soil qualities, the mineralogical as well as the organic composition, with a view to higher yields, is becoming more and more intense. the objective this study was to qualitatively verify the mineralogical effects of different management types: conventional , minimum and no-tillage for 24 years on a red latosol in ponta grossa, pr, brazil, by the following techniques: x-ray diffraction, x-ray fluorescence and fourier transform infrared. no significant changes in the mineralogy of the red latosol were observed by the techniques applied, as a result of the different management types. it was however possible to qualitatively verify the presence of the following minerals: gibbsite, kaolinite, halloysite, montmorillonite, hematite, rutile, anatase, goethite and quartz.
Simula??o do perfil s?nico a partir dos perfis de raios gama e de desistividade em po?os da Bacia de Campos
Leite, Marcos;Carrasquilla, Abel;Silva, Jadir da;
Revista Brasileira de Geofísica , 2008, DOI: 10.1590/S0102-261X2008000200003
Abstract: the knowledge of the mechanical properties of the rocks is essential in the calculation of the stability of the oil wells and in the elaboration of drilling projects, because they help in the selection of the best equipments for each geologic scene. in these activities, the most important mechanical property is the rock compressibility, which can be calculated from the sonic geophysical log, but this one, not always available in the well data set. in order to minimize this limitation, it was developed, in this work, a methodology to simulate it through an algorithm that utilizes fuzzy logic concepts, using as input data gamma ray and resistivity logs. the basic principle of this methodology is to propose that any geophysical log, including the sonic log, can be considered function of other measured geophysical logs in the same depths. on the other hand, to test the confidence of this approach, it was compared with two others commonly used in the simulation of logs: the linear multiple regression and the neural network back-propagation, showing, our methodology, however, better results. finally, to validate the method, it was tested using wells from namorado oil field in campos basin, which contains gamma ray, sonic and resistivity logs.
Compara??o de métodos de medida da densidade do solo
Pires, Luiz Fernando;Rosa, Jadir Aparecido;Timm, Luís Carlos;
Acta Scientiarum. Agronomy , 2011, DOI: 10.4025/actasciagron.v33i1.5507
Abstract: soil bulk density (ds) is traditionally used as an indicator of soil structure and soil compaction. the objective of this work was to compare ds values obtained through conventional methods like paraffin sealed clod (mtp) and volumetric ring (mav), and nuclear methods like computerized tomography (mtc), gamma-ray attenuation (mag) and neutron-gamma surface gauge (msn). soil samples were collected in areas under conventional tillage and no-tillage systems. sixteen samples were collected in the soil surface layer for the analyses by the mav, mtp, mtc, and mag. for the msn, sixteen readings were carried out throughout the experimental area. the highest ds values for the conventional tillage system were obtained for the mtp, mpc, and mag, without significant differences. also the statistic test indicates that the lowest ds values obtained for the msn and mav did not differ significantly. regarding to the no-tillage system, only the mav and mag had been compared, whose ds values did differ significantly.
Compara o de métodos de medida da densidade do solo = Comparison of methods to evaluate soil bulk density.
Luiz Fernando Pires,Jadir Aparecido Rosa,Luís Carlos Timm
Acta Scientiarum : Agronomy , 2011,
Abstract: A densidade do solo (ds) tem sido usada como um parametro importante de caracteriza o física da estrutura do solo e como um indicador de sua compacta o. Este trabalho teve como objetivo comparar os valores de ds obtidos através de métodos convencionais, como torr o parafinado (MTP) e anel volumétrico (MAV), e nucleares, como tomografia computadorizada (MTC), atenua o gama (MAG) e sonda de superfície nêutron-gama (MSN). Foram feitas coletas de amostras em áreas submetidas às práticas de manejo de plantio convencional e plantio direto. Para as análises pelos MAV, MTP, MTC e MAG foram coletadas 16 amostras na camada superficial do solo e para o MSN foramrealizadas leituras em 16 pontos distintos ao longo da área experimental. Os maiores valores de ds foram obtidos para os MTP, MTC e MAG (plantio convencional) n o diferindo estatisticamente entre si. Os menores valores de ds foram obtidos para os MSN e MAV n o diferindo estatisticamente entre si. Com rela o ao plantio direto foram comparados somente os MAV e MAG com os valores de ds diferindo estatisticamente entre si. Soil bulk density (ds) is traditionally used as an indicator of soil structure and soil compaction. The objective of this work was to compare ds values obtained through conventional methods like paraffinsealed clod (MTP) and volumetric ring (MAV), and nuclear methods like computerized tomography (MTC), gamma-ray attenuation (MAG) and neutron-gamma surface gauge (MSN). Soil samples were collected in areas under conventional tillage and no-tillage systems. Sixteen samples were collected in the soil surface layer for the analyses by the MAV, MTP, MTC, and MAG. For the MSN, sixteen readings were carried out throughout the experimental area. The highest ds values for the conventional tillage system were obtained for the MTP, MPC, and MAG, without significant differences. Also the statistic test indicates that the lowest ds values obtained for the MSN and MAV did not differ significantly. Regarding to the no-tillage system, only the MAV and MAG had been compared, whose ds values did differ significantly.
Evaluation of a computer model to simulate water table response to subirrigation
Rosa, Jadir Aparecido;Smajstrla, Allen George;Campbell, Kenneth Leonard;Locascio, Salvadore Jose;
Pesquisa Agropecuária Brasileira , 2002, DOI: 10.1590/S0100-204X2002001200010
Abstract: the objective of this work was to evaluate the water flow computer model, watable, using experimental field observations on water table management plots from a site located near hastings, fl, usa. the experimental field had scale drainage systems with provisions for subirrigation with buried microirrigation and conventional seepage irrigation systems. potato (solanum tuberosum l.) growing seasons from years 1996 and 1997 were used to simulate the hydrology of the area. water table levels, precipitation, irrigation and runoff volumes were continuously monitored. the model simulated the water movement from a buried microirrigation line source and the response of the water table to irrigation, precipitation, evapotranspiration, and deep percolation. the model was calibrated and verified by comparing simulated results with experimental field observations. the model performed very well in simulating seasonal runoff, irrigation volumes, and water table levels during crop growth. the two-dimensional model can be used to investigate different irrigation strategies involving water table management control. applications of the model include optimization of the water table depth for each growth stage, and duration, frequency, and rate of irrigation.
Permeabilidade ao ar em Latossolo Vermelho sob diferentes sistemas de manejo
Rodrigues, Sueli;Silva, Alvaro Pires da;Giarola, Neyde Fabíola Balarezo;Rosa, Jadir Aparecido;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000100010
Abstract: air permeability (kα) can be used to assess soil structure changes resulting from different tillage systems. this study tested the hypothesis that the reduced soil disturbance in no-tillage results in continuous pores and better soil aeration conditions. the objective was to evaluate the aeration of a rhodic hapludox under conventional tillage (ct) and no-tillage (nt), based on soil air permeability (kα), air-filled porosity (εa) and indices of pore continuity (k1 and n). eighty undisturbed soil cores (2 treatments x 2 depths x 20 repetitions) were collected from each tillage system at 0-0.10 and 0.10-0.20 m in an experimental area of the agronomic institute of paraná in ponta grossa, paraná. after the samples had been saturated and equilibrated at six matric potentials (-2, -6, -10, -30, -70, and -100 kpa), the air permeability and air-filled porosity were determined for each matrix potential. the soil bulk density, particle density, organic carbon and soil porosity were also evaluated. soil bulk density was not a limiting factor, with values below the critical limit for clay soils in both systems. in nt, the greater micropore volume was related to higher water retention in the evaluated moisture range (-2 to -100 kpa) and greater volume of pores blocked for air flow (εb), thus reducing kα in this system. at 0-0.20 m, the indices of pore continuity (k1 and n) indicated more continuous pores in ct than nt, contradicting the hypothesis tested.
Evaluation of a computer model to simulate water table response to subirrigation
Rosa Jadir Aparecido,Smajstrla Allen George,Campbell Kenneth Leonard,Locascio Salvadore Jose
Pesquisa Agropecuária Brasileira , 2002,
Abstract: The objective of this work was to evaluate the water flow computer model, WATABLE, using experimental field observations on water table management plots from a site located near Hastings, FL, USA. The experimental field had scale drainage systems with provisions for subirrigation with buried microirrigation and conventional seepage irrigation systems. Potato (Solanum tuberosum L.) growing seasons from years 1996 and 1997 were used to simulate the hydrology of the area. Water table levels, precipitation, irrigation and runoff volumes were continuously monitored. The model simulated the water movement from a buried microirrigation line source and the response of the water table to irrigation, precipitation, evapotranspiration, and deep percolation. The model was calibrated and verified by comparing simulated results with experimental field observations. The model performed very well in simulating seasonal runoff, irrigation volumes, and water table levels during crop growth. The two-dimensional model can be used to investigate different irrigation strategies involving water table management control. Applications of the model include optimization of the water table depth for each growth stage, and duration, frequency, and rate of irrigation.
Visual soil structure quality assessment on Oxisols under no-tillage system
Giarola, Neyde Fabíola Balarezo;Silva, Alvaro Pires da;Tormena, Cássio Ant?nio;Ball, Bruce;Rosa, Jadir Aparecido;
Scientia Agricola , 2010, DOI: 10.1590/S0103-90162010000400016
Abstract: methods for evaluation the soil structure quality based on field evaluations are useful to determine strategies for soil management, with the advantage of requirement the use of little equipment and the possibility of immediate interpretation. a new methodology was recently developed to temperate soils for this purpose, called visual soil structure assessment (ball et al., 2007). it was tested the hypothesis that it is possible to apply and advance in the interpretation of the results from use of visual soils structure assessment in cultivated oxisols. therefore the goal of this study was to apply, evaluate and enhance the potential of the methodology developed by ball et al. (2007) in two oxisols under long-term, no-till in parana state, brazil, as well as in a soil under native forest, used as reference of soil structural quality. the proposed implementation and progress in terms of structural quality for the distinct layers provided an assessment of soil physical quality more practical and detailed. this is useful to support the selection of appropriate techniques for mechanical and biological management systems in order to achieve the physical quality of soil suitable for crop development. visual scores of soil structure quality proposed by ball et al. (2007) can be applied to brazilian oxisols cultivated under no-tillage system.
Marx e as no es de progresso, liberdade e sujeito na história = Marx’s notions of progress, liberty and subject in History
Jadir Antunes
Acta Scientiarum : Human and Social Sciences , 2009,
Abstract: Este artigo tem por objetivo mostrar, a partir da concep o de Karl Marx, como se desenvolveram as no es de progresso, liberdade e sujeito ao longo da história ocidental. Segundo Marx, essas no es surgiram juntamente com a apropria o privada da Natureza, apartir da dissolu o da chamada comunidade primitiva e da emergência da escravid o antiga. Essas no es continuaram a se desenvolver ao longo da Idade Média europeia e atingiram seu auge com o aparecimento do trabalhador assalariado posto pelo capitalismo moderno. Oartigo pretende, ainda, mostrar a diferen a entre a concep o materialista de Marx e a concep o teleológica de Hegel – que pensa a história como uma grande teodiceia rumo à liberdade e à racionalidade – e em que sentido Marx teria invertido esta concep o mistificada da história. The purpose of this article is to show, from the philosophical and dialectical conception of Karl Marx, how the notions of progress, liberty and subject have been developed throughout Western History. According to Marx, those notions arose together with the privateappropriation of Nature that began with the dissolution of the so-called primitive community and the emergence of ancient slavery. These notions continued to develop along the European Middle Ages and reached their peak with the appearance of the wage worker imposed by modern capitalism. The article also aims to show the differencebetween Marx’s materialistic conception and Hegel’s teleological conception (which reflects about History in terms of a great theodicy moving towards liberty and rationality) and the ways by which Marx inverted this mystified conception of History.
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