9,498 research outputs found

    Doses de composto orgânico proveniente de resíduos da produção e do abate de pequenos ruminantes na cultura do milho.

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    Resumo: A atividade agrícola gera enorme quantidade de resíduo que muitas vezes são desperdiçados, mas grande parte dele pode ser aproveitada para inúmeros fins. Estudos acerca das potencialidades desses resíduos na agricultura são importantes para o reaproveitamento desses materiais. Objetivou-se avaliar os efeitos da aplicação de composto orgânico proveniente de resíduos da produção e abate de pequenos ruminantes como adubo orgânico na produção de plantas de milho e compará-lo com adubos minerais. Assim, foram realizados dois ensaios, ambos em delineamento em blocos ao caso. O primeiro avaliou-se quantidades crescentes de composto, sendo as doses 3, 6, 9, 12 e 24 t ha-1 de composto orgânico e um tratamento adicional com adubos minerais, portanto foram 6 tratamentos e 4 repetições, num total de 24 parcelas. No segundo empregaram-se duas fontes (adubo mineral e composto orgânico) e quatro doses equivalentes em nitrogênio (27,5; 55; 110 e 165 kg ha-1 de N), sendo um fatorial 2 x 4 e um tratamento adicional sem fertilizantes, com três repetições, num total de 27 parcelas. O aumento das doses de composto influenciou significativamente o aumento de parâmetros como o número de folhas, índice SPAD, massa da matéria seca da espiga e massa de matéria seca total na cultura do milho. A aplicação de adubo orgânico ou mineral proporcionou superioridade nos parâmetros avaliados quando em comparação com milho produzido sem adubos. A eficiência do uso do nitrogênio decresce com o aumento das doses de N aplicadas independente da fonte utilizada na cultura do milho. [Doses of organic compound from composting of small ruminants on corn plants]. Abstract: The agricultural activities generate a huge amount of residues which are often wasted, even though much of them can be used for numerous purposes. Studies about the potential of such residues in agriculture are important to recycle these materials and to the environment. We aimed to assess the effects of application of organic compound which was prepared with disposal and slaughter of small ruminants after composting process in order to grow corn plants and to compare with mineral fertilizers. Hence, two tests were conducted based on completely randomized design. In the first test, we evaluated increasing amounts of this compound, 3, 6, 9, 12 and 24 t ha-1, one additional treatment with mineral fertilizer was added as well, so there were 6 treatments and 4 replicates, a total of 24 plots. In the second test, two sources of mineral nutrition were employed, organic compound and mineral fertilizer, and four rates in nitrogen (27,5; 55; 110 and 165 kg ha-1 N). So we had a 2x4 factorial and an additional treatment without any of those sources. All treatment had three replications. Thus, we had 27 plots. As the doses of compost increased the following parameters such as number of leaves, SPAD index, dry weight of ear of corn and total increased. The application of organic or mineral fertilizer revealed superiority in the evaluation parameters when compared with corn produced without fertilizers. As the doses of N increased the efficiency of nitrogen use decreases regardless of any source used in corn.Monografia (Bacharel em Biologia) - Universidade Estadual Vale do Acaraú, Sobral. Orientador: Henrique Antunes de Souza (CNPC)

    Magnetically assisted self-injection and radiation generation for plasma based acceleration

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    It is shown through analytical modeling and numerical simulations that external magnetic fields can relax the self-trapping thresholds in plasma based accelerators. In addition, the transverse location where self-trapping occurs can be selected by adequate choice of the spatial profile of the external magnetic field. We also find that magnetic-field assisted self-injection can lead to the emission of betatron radiation at well defined frequencies. This controlled injection technique could be explored using state-of-the-art magnetic fields in current/next generation plasma/laser wakefield accelerator experiments.Comment: 7 pages, 4 figures, accepted for publication in Plasma Physics and Controlled Fusio

    Dynamics of magnetic moments coupled to electrons and lattice oscillations

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    Inspired by the models of A. Rebei and G. J. Parker and A. Rebei et. al., we study a physical model which describes the behaviour of magnetic moments in a ferromagnet. The magnetic moments are associated to 3d electrons which interact with conduction band electrons and with phonons. We study each interaction separately and then collect the results assuming that the electron-phonon interaction can be neglected. For the case of the spin-phonon interaction, we study the derivation of the equations of motion for the classical spin vector and find that the correct behaviour, as given by the Brown equation for the spin vector and the Bloch equation, using the results obtained by D. A. Garanin for the average over fluctuations of the spin vector, can be obtained in the high temperature limit. At finite temperatures we show that the Markovian approximation for the fluctuations is not correct for time scales below some thermal correlation time Ï„Th\tau_{Th}. For the case of electrons we workout a perturbative expansion of the Feynman-Vernon functional. We find the expression for the random field correlation function. The composite model (as well as the individual models) is shown to satisfy a fluctuation-dissipation theorem for all temperature regimes if the behaviour of the coupling constants of the phonon-spin interaction remains unchanged with the temperature. The equations of motion are derived

    Modelling of sanitary sewer systems integrating rainfall-derived infiltration and inflow

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    Wastewater utilities often have management difficulties when excessive wet-weather flow leads to serious impacts in public health and environment as well as disturbing operational conditions in wastewater treatment plants (WWTP). This phenomenon, resulting from rainfall-derived infiltration and inflow (RDII), occurs mainly due to defects in pipes and manholes (infiltration) and to illicit connections from downspouts, foundation drains or cross-connections with storm sewers (inflow), contributing to sanitary sewer overflows (SSOs). These difficulties related to SSOs negatively affect: (i) the capacity and operation of sanitary sewer collection; (ii) the performance and treatment efficiency of WWTP; (iii) the risk of a public health hazards and environmental contamination. This well-known wastewater managerial problem is very difficult to locate and quantify in practice since the needed adequate measurement equipment often entails unsustainable costs for utilities. Wastewater flow mathematical modelling integrating a digital cadastral database using Geographic Information Systems (GIS) constitutes a sound methodology in predicting sanitary sewer systems performance which is a critical issue within SSOs reduction and remediation programs. This paper presents the implementation of a methodology based on hydroinformatic tools to determine the contribution of RDII in complex municipal sewer systems in order to establish adequate urban wastewater management policies that will effectively mitigate SSOs. USEPA SWMM, and digital cadastral database with field verification were applied in a simulation study of the small scale sanitary sewer network of Espinho (Braga, Portugal) whose results will be used in a larger scale to create a city-wide model for wastewater systems management

    Modelling of Sanitary Sewer Systems integrating Rainfall-Derived Infiltration and Inflow

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    Municipal wastewater management difficulties may occur when excessive wet weather flow determine sanitary sewer overflows (SSOs) mainly caused by the contribution of rainfall-derived infiltration and inflow (RDII) into sanitary sewers. This excess of wet weather flow can lead to serious problems to public health and environment as well as to suboptimal operation of wastewater treatment plants. This paper presents the implementation of a methodology based on hydroinformatic tools to determine the contribution of RDII in complex municipal sewer systems in order to establish adequate urban wastewater management policies that will effectively mitigate SSOs. USEPA SWMM, and digital cadastral database with field verification were applied in a simulation study of a small scale sanitary sewer network whose results will be used in a larger scale to create a city-wide model for wastewater systems management

    A evolução da caprinovinocultura brasileira.

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    Chaos in black holes surrounded by gravitational waves

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    The occurrence of chaos for test particles moving around Schwarzschild black holes perturbed by a special class of gravitational waves is studied in the context of the Melnikov method. The explicit integration of the equations of motion for the homoclinic orbit is used to reduce the application of this method to the study of simple graphics.Comment: 15 pages, LaTex

    Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam

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    It is shown that co-linear injection of electrons or positrons into the wakefield of the self-modulating particle beam is possible and ensures high energy gain. The witness beam must co-propagate with the tail part of the driver, since the plasma wave phase velocity there can exceed the light velocity, which is necessary for efficient acceleration. If the witness beam is many wakefield periods long, then the trapped charge is limited by beam loading effects. The initial trapping is better for positrons, but at the acceleration stage a considerable fraction of positrons is lost from the wave. For efficient trapping of electrons, the plasma boundary must be sharp, with the density transition region shorter than several centimeters. Positrons are not susceptible to the initial plasma density gradient.Comment: 9 pages, 9 figures, 1 table, 44 reference
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