202 research outputs found
Determinação de cálcio em cereal matinal utilizando espectroscopia de emissão óptica com plasma induzido por laser.
Composição química, fracionamento da proteina e digestibilidade in vitro do mamãozinho-de-veado (Jacaratia corumbensis O. kuntze).
O atual experimento teve o objetivo de avaliar a composição química, a digestibilidade in vitro da matéria seca, como também fracionar a proteina da parte aérea e do tubérculo do mamãozinho-de-veado. Os mamõezinhos-de-veado utilizados apresentavam idade aproximada de quatro anos e foram colhidos logo após o período das chuvas. As folhas, talos finos e tubérculos foram colhidos de cinco plantas aleatórias no interior da caatinga, tentando-se uma melhor representatividade amostral. O peso médio dos tubérculos coletados foi de 15 kg. As folhas e ramos finos do mamãozinho apresentaram valores de parede celular (tabela 1) que denotam pouca característica de alimento fibroso e o incluem como possível alternativa no fornecimento de proteína para os animais do semi-árido. Em períodos de estiagem, quando a maioria das forragens da caatinga apresenta baixo valor nutritivo, o tubérculo do mamãozinho-de-veado pode ser utilizado tanto como fonte de água, como também sendo fonte de energia e proteína, complementando as dietas dos animais do sertão
Composição bromatológica e pH de silagens de maniçoba com adição de resíduo de vitivinícolas.
O presente trabalho foi conduzido no Campo Experimental da Embrapa Semi-Árido em Petrolina/PE. O objetivo foi avaliar a composição bromatológica e pH das silagens de maniçoba com adição de resíduo de vitivinícolas (RV), As silagens foram armazenadas em silos experimentais e avaliadas aos 60 dias de fermentação. Foram coletadas amostras para determinação dos teores de matéria seca (MS), proteína bruta (PB), matéria mineral (MM), matéria orgânica (MO), extrato etéreo (EE), lignina (LIG), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e pH. Os dados foram submetidos à análise de regressão. Houve efeito linear crescente do teor de MS, MM, EE,= e LIG, com a elevação dos níveis de resíduo de RV. A PB das silagens aumentou após 60 dias de fermentação em todos os tratamento. Não se verificou efeito dos níveis para FDN e FDA com adição de RV. A inclusão de RV promoveu um efeito benéfico em relação aos valores de pH
Comparing faceted and smoothed tool surface descriptions in sheet metal forming simulation
This study deals with different tool surface description
methods used in the finite element analysis of sheet metal
forming processes. The description of arbitrarily-shaped tool
surfaces using the traditional linear finite elements is compared
with two distinct smooth surface description approaches:
(i) Bézier patches obtained from the ComputerAided
Design model and (ii) smoothing the finite element
mesh using Nagata patches. The contact search algorithm is
presented for each approach, exploiting its special features in
order to ensure an accurate and efficient contact detection. The
influence of the tool modelling accuracy on the numerical
results is analysed using two sheet forming examples, the
unconstrained cylindrical bending and the reverse deep drawing
of a cylindrical cup. Smoothing the contact surfaces with
Nagata patches allows creating more accurate tool models,
both in terms of shape and normal vectors, when compared
with the conventional linear finite element mesh. The computational
efficiency is evaluated in this study through the total
number of increments and the required CPU time. The mesh
refinement in the faceted description approach is not effective
in terms of computational efficiency due to large discontinuities
in the normal vector field across facets, even when
adopting fine meshes.The authors gratefully acknowledge the financial
support of the Portuguese Foundation for Science and Technology (FCT)
via the projects PTDC/EME-TME/118420/2010 and PEst-C/EME/
UI0285/2013 and by FEDER funds through the program COMPETE –
Programa Operacional Factores de Competitividade, under the project
CENTRO-07-0224-FEDER-002001 (MT4MOBI). The first author is
also grateful to the FCT for the PhD grant SFRH/BD/69140/2010.info:eu-repo/semantics/publishedVersio
Is there association between chronic kidney disease and dental caries? A case-controlled study
The purpose of this study was to assess the association between chronic kidney diseases (CKD) and dental caries. 107 patients with CKD and 107 with no systemic alteration were randomly included. DMFT (decayed, missing, and filled teeth), plaque index, colony-forming units (CFU) of Streptococcus mutans and salivary composition (IgA total, IgA anti- Streptococcus mutans, calcium and urea) were evaluated. McNemar and Wilcoxon tests were used to compare test and control groups. Spearman test was used to correlate time of hemodialysis and variables studied. Associations between variables were evaluated by logistic regression analysis. The number of filled teeth, the amount of IgA anti-Streptococcus mutans, salivary urea, education level, monthly income and the amount of CFU of Streptococcus mutans were statistically different between groups. There was a positive correlation between the duration of hemodialysis (Hd) and the amount of IgA anti-Streptococcus mutans, urea in saliva, and the number of CFU of Streptococcus mutans. In the adjusted model, a higher incidence of CFU mutans streptococci, elevated salivary urea, smaller number of filled teeth, lower DMFT, and less calcium salivary were associated with CKD. Programs to prevent and treat oral problems and regular follow-up at the beginning of dialysis are necessary to increase patients? awareness of their condition
Avaliação e caracterização de sistemas de produção de açaizeiros apropriados para o agronegócio (projeto de pesquisa).
Projeto
Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy
The recent trend to reduce the thickness of metallic sheets used in forming processes strongly increases the likelihood of the occurrence of wrinkling. Thus, in order to obtain defect-free components, the prediction of this kind of defect becomes extremely important in the tool design and selection of process parameters. In this study, the sheet metal forming process proposed as a benchmark in the Numisheet 2014 conference is selected to analyse the influence of the tool geometry on wrinkling behaviour, as well as the reliability of the
developed numerical model. The side-wall wrinkling during the deep drawing process of a cylindrical cup in AA5042 aluminium alloy is investigated through finite element simulation and experimental measurements. The material plastic anisotropy is modelled with an advanced yield criterion beyond the isotropic (von Mises) material behaviour. The results show that the shape of the wrinkles predicted by the numerical model is strongly affected by the finite element mesh used in the blank discretization. The accurate modelling of the plastic anisotropy of the aluminium alloy yields numerical results that are in good agreement with the experiments, particularly the shape and location of the wrinkles. The predicted punch force evolution is strongly influenced by the friction coefficient used in the model. Moreover, the two punch geometries provide drawn cups with different wrinkle waves, mainly differing in amplitude.The authors gratefully acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) under project PTDC/EMS-TEC/1805/2012. The first author is also grateful to the FCT for the Postdoctoral grant SFRH/BPD/101334/2014 and P.D. Barros is grateful to the FCT for the PhD Grant SFRH/BD/98545/2013info:eu-repo/semantics/publishedVersio
Selection indexes for nellore production system in the Brazilian Pantanal.
The objective was to develop selection indexes for Nellore cattle raised in full-cycle production system in the Brazilian Pantanal. The resulting offspring are retained as replacements or sold at two years of age. Preliminary analyses explored effects of scale on economic values (EV). However, given the available data, these effects were very small. Presented herein are results from a simulated system consisting of 5,000 cows with all animals maintained on pasture as is typical in Pantanal. The EV were determined by approximating the partial derivatives of the profit function, changing one trait at a time, by one unit, while keeping the other traits constant. Traits in the breeding objective were mature cow weight, direct and maternal weaning weight, postweaning average daily gain, subcutaneous fat depth, longissimus muscle area, and stayability. Economic values were calculated on the basis of number of animals (per head), number of animal units, and arroba of carcasss weight. Regardless of the basis, maternal weaning weight and subcutaneous fat depth made negligible contributions to the breeding objective. Proportions of variation in the breeding objectives (per head, per animal unit, per arroba) explained by cow weight, direct weaning weight, postweaning average daily gain, stayability, and longissimus muscle area were: 13, 13, 17; 6, 1, 5; 3, 3, 4; 67, 67, 61; and 11, 17, 13, respectively. These indexes may aid Nellore breeders in their selection decisions, thus facilitating the genetic progress and increased productivity and profitability of Pantanal herds.Animal production systems and agribusiness
Gas exchange and leaf contents in bell pepper under energized water and biofertilizer doses
Evaluation of strain and stress states in the single point incremental forming process
Single point incremental forming (SPIF) is a promising
manufacturing process suitable for small batch production.
Furthermore, the material formability is enhanced in
comparison with the conventional sheet metal forming processes,
resulting from the small plastic zone and the incremental
nature. Nevertheless, the further development of the SPIF
process requires the full understanding of the material deformation
mechanism, which is of great importance for the effective
process optimization. In this study, a comprehensive
finite element model has been developed to analyse the state
of strain and stress in the vicinity of the contact area, where the
plastic deformation increases by means of the forming tool
action. The numerical model is firstly validated with experimental
results from a simple truncated cone of AA7075-O
aluminium alloy, namely, the forming force evolution, the
final thickness and the plastic strain distributions. In order to
evaluate accurately the through-thickness gradients, the blank
is modelled with solid finite elements. The small contact area
between the forming tool and the sheet produces a negative
mean stress under the tool, postponing the ductile fracture
occurrence. On the other hand, the residual stresses in both
circumferential and meridional directions are positive in the
inner skin of the cone and negative in the outer skin. They
arise predominantly along the circumferential direction due to
the geometrical restrictions in this direction.The authors would like to gratefully acknowledge the
financial support from the Portuguese Foundation for Science and Technology
(FCT) under project PTDC/EMS-TEC/1805/2012. The first author is
also grateful to the FCT for the postdoctoral grant SFRH/BPD/101334/2014.info:eu-repo/semantics/publishedVersio
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