A finite volume method for a convection- diffusion equation involving a Joule term

International audienceThis work is devoted to a Finite Volume method to approximate the solution of a convection-diffusion equation involving a Joule term. We propose a way 5 to discretize this so-called "Joule effect" term in a consistent way with the non linear diffusion one, in order to ensure some maximum principle properties on the solution. We then investigate the numerical behavior of the scheme on two original benchmarks

Manejo e eficiência de uso da água de irrigação da cultura do abacateiro no Submédio São Francisco.

As características climáticas e a possibilidade de produção de frutas, entre as quais o abacate em períodos de escassez em outros mercados como o do Sul e Sudeste sugerem a necessidade de ajustes no manejo da cultura ou em técnicas específicas da cultura. Portanto o objetivo desse trabalho foi estimar a eficiência de uso da água para três variedades de abacateiro no Submédio São Francisco

Produtividade de genótipos de feijão comum com altos teores de ferro e zinco submetidos a deficit hídrico no Semiárido brasileiro.

bitstream/item/53786/1/BPD85.pd

Physiological and biochemical responses of sugarcane varieties to salt stress.

Salt stress is one of the most limiting environmental factors for agricultural yields in the Semiarid region of Brazil. Considering the expansion of areas with sugarcane crops in this region, the selection of more adapted plant varieties to this environment is an essential tool for the sustainability of this activity. Thus, the objective of the present work was to evaluate the physiological and biochemical responses of plants of ten sugarcane varieties to salt stress. The experiment was conducted in a greenhouse using a randomized block design, in a 6×10 factorial arrangement consisting of six salinity levels in the irrigation water (0, 1.0, 2.0, 4.0, 6.0, and 8.0 dS m-1) and ten sugarcane varieties (VAT 90212, RB 72454, RB 867515, Q 124, RB 961003, RB 957508, SP 791011, RB 835089, RB 92579, and SP 943206), with three replications. Salt waters were applied every two days to increase the soil moisture to field capacity and promote leaching. The gas exchange, chlorophyll content, and total soluble and reducing sugars of leaves were evaluated at 90 days after planting. The highest chlorophyll contents were found in plants of the varieties Q 124, RB 96103, RB 835089, and SP 943206. The effect of salinity on the sugarcane plants affected their leaf gas exchanges and total soluble and reducing sugar contents, denoting the adaptability of plants to the stress conditions evaluated. The decrease of stomatal conductance resulted in decreases in photosynthetic rates in plants of all sugarcane varieties evaluated, except for RB 86751

ChemicalDrift 1.0: an open-source Lagrangian chemical-fate and transport model for organic aquatic pollutants

A new model for transport and fate of chemicals in the aquatic environment is presented. The tool, named ChemicalDrift, is integrated into the open-source Lagrangian framework OpenDrift and is hereby presented for organic compounds. The supported chemical processes include the degradation, the volatilization, and the partitioning between the different phases that a target chemical can be associated with in the aquatic environment, e.g. dissolved, bound to suspended particles, or deposited to the seabed sediments. The dependencies of the chemical processes on changes in temperature, salinity, and particle concentration are formulated and implemented. The chemical-fate modelling is combined with wide support for hydrodynamics by the integration within the Lagrangian framework which provides e.g. advection by ocean currents, diffusion, wind-induced turbulent mixing, and Stokes drift generated by waves. A flexible interface compatible with a wide range of available metocean data is made accessible by the integration, making the tool easily adaptable to different spatio-temporal scales and fit for modelling of complex coastal regions. Further inherent capabilities of the Lagrangian approach include the seamless tracking and separation of multiple sources, e.g. pollutants emitted from ships or from rivers or water treatment plants. Specific interfaces to a dataset produced by a model of emissions from shipping and to an unstructured-grid oceanographic model of the Adriatic Sea are provided. The model includes a database of chemical parameters for a set of poly-aromatic hydrocarbons and a database of emission factors for different chemicals found in discharged waters from sulfur emission abatement systems in marine vessels. A post-processing tool for generating mean concentrations of a target chemical, over customizable spatio-temporal grids, is provided. Model development and simulation results demonstrating the functionalities of the model are presented, while tuning of parameters, validation, and reporting of numerical results are planned as future activities. The ChemicalDrift model flexibility, functionalities, and potential are demonstrated through a selection of examples, introducing the model as a freely available and open-source tool for chemical fate and transport that can be applied to assess the risks of contamination by organic pollutants in the aquatic environment

Produção de manga e banana orgânicas em área de pequenos produtores do sertão da Bahia.

Edição dos Resumos do 7 Congresso Brasileiro de Agroecologia, Fortaleza, dez. 2011

Recomendações para o cultivo do pomeleiro Flame nas condições do Vale do São Francisco.

O pomelo ou grapefruit (Citrus paradisiMacf.) é uma espécie cítrica considerada um híbrido natural de toranja, cuja origem presume-se ser da Jamaica ou Barbados. No Brasil é pouco conhecido, apresentando um sabor ácido e ligeiramente amargo, sendo utilizado na indústria de sucos, geleias, doces e cosméticos. Apresenta ainda propriedades medicinais relacionadas à perda de peso, ao controle da frequência cardíaca e da pressão arterial. Das espécies cítricas, o pomeleiro e a limeira ácida são as que têm se adaptado melhor à região Nordeste, principalmente no Submédio do Vale do São Francisco, região que apresenta características tipicamente tropicais e condições climáticas bastante .diferenciadasbitstream/item/175405/1/INT132-2.pd