Magnetic Properties of the Metamagnet Ising Model in a three-dimensional Lattice in a Random and Uniform Field

By employing the Monte Carlo technique we study the behavior of Metamagnet Ising Model in a random field. The phase diagram is obtained by using the algorithm of Glaubr in a cubic lattice of linear size $L$ with values ranging from 16 to 42 and with periodic boundary conditions.Comment: 4 pages, 6 figure

Amostragem de toras de árvores de Eucalyptus grandis selecionadas para finalidades de serraria e energia.

A partir da avaliação de dez características tecnológicas de madeira de eucalipto para fins de serraria e energia, desenvolveu-se procedimento estatístico multivariado para se determinar a seqüência de toras a ser amostrada, de forma a representar acumuladamente toda a variação estatística presente na árvore e, com isso, estabelecer a intensidade adequada de amostragem. Neste estudo, foram utilizadas 40 toras oriundas de quatro árvores de Eucalyptus grandis aos 18 anos de idade procedentes de Concórdia, SC. Com o uso de técnicas de regressão multivariada de componentes principais e seleção por etapas, chegou-se à conclusão que amostrandose apenas duas toras, correspondentes à primeira (0,05 m a 2,60 m) e quarta (8,85 m a 11,40 m) posições dentro da árvore, foi possível abranger 99,2 % de toda a variação inicialmente detectada. No caso de optar-se por utilizar apenas uma única tora, a indicação recaiu para a quarta tora da árvore, a qual representou 97,5 % de toda a variação contida nos dados originais. Para a referida população, o procedimento estatístico adotado evidenciou a possibilidade de se reduzir substancialmente os elevados gastos, de tempo e de recursos financeiros, associados a avaliações dessa natureza, sem comprometer a qualidade da informação estatística original contida em todas as toras que seriam convencionalmente amostradas

PARTICLE SIZE DISTRIBUTION CORRECTION METHOD USING A SIMULATED ANNEALING TECHNIQUE

The procedure for obtaining the particle size distribution by visual inspection of a sample involves stereological errors, given the cut of the sample. A cut particle, supposedly spherical, with radius R, will be counted as a circular particle with radius r, r≤R. The difference between r and R depends on how far from the center of the sphere the cut was performed. This introduces errors when the extrapolation of the properties from two to three dimensions during the analysis of a sample. The usual method is to correct the distribution by probabilistic functions, which have large errors. This paper presents a method to reduce the error inherent to this problem. The method is to compute a simulation of the preparation process in a sample whose structure can be described by non-penetrating spheres of various diameters which meet a known probability distribution function, for example, a log-logistic function, or even a constant function. For each distribution radius, a number of spheres is generated and virtually cut, generating a bi-dimensional (2D) distribution. The 2D curves of the spheres distribution obtained in this simulation are compared with that obtained by the experimental procedure and then the parameters of the threedimensional distribution function are adjusted until the 2D curves are similar to the experimental one using the optimization method Simulated Annealing for the curve-fitting. In future this method will be applied to the analysis of the oil reservoir rocks

Tutoramento de plantas de ervilha visando à produção de grãos secos.

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Lipase production by Aspergillus niger 11T53A14 in wheat bran using experimental design methodology.

Lipases have various industrial applications and their production by filamentous fungi in solid state fermentation (SSF) process is of interest. In this work the lipase enzyme production by the mutant Aspergillus niger 11T51A14, which is a well-known lipase producer was studied using wheat bran as substrate. Microorganism used in fermentation process was inoculated at a concentration of 107 spores/gm into the medium containing nitrogen (ammonium sulfate), sunflower soapstock and wheat bran. The SSF process for enzyme production was carried out in aerated columns immersed in a water bath at 32ºC for 72 h. The process was studied using a central composite rotatable design 22, where variables tested were the nitrogen concentration (0.32-0.88 % w/w) and the volume of liquid (60.9-89.1 mL). The lipase activity was analyzed in enzymatic extracts. The wheat bran, in the fermentation medium, acted as a carbohydrate source and as an inducer for the lipase production. The maximum enzyme activity found was 153.4 U/gdm, with a nitrogen concentration of 0.6 % and 89.1 mL of volume of liquid. The response surface model demonstrated that higher volume of liquid had a positive effect in lipase activity, while nitrogen concentration showed an optimal range (0.4-0.6%)

Podridão do colo (Sclerotium rolfsii Sacc.) em pimenta salada ou pimenta doce (Capsicum annum) no Estado do Amapá.

A cultura da pimenta salada é uma importante fonte de renda para o agricultor amapaense. É também conhecida como pimenta do cheiro ou pimenta doce, no Amapá. Em levantamentos efetuados nos diversos municípios do estado, através de um projeto em parceria entre o Centro de Pesquisa Agroflorestal do Amapá - Embrapa Amapá e o Instituto de Pesquisa Florestal do Amapá, verificou-se a ocorrência de um fungo de solo (Sclerotium rolfsii Sacc.) que ocasiona a murcha de plantas de pimenta salada, descrito pela primeira vez por Rolfs, em 1892, em tomateiros na Flórida, Estados Unidos e segundo Moraes (1982), tal fungo apresenta uma maior distribuição em regiões tropicais e subtropicais, onde a alta temperatura prevalece durante as estações chuvosas.bitstream/item/97385/1/CPAF-AP-2002-Podridao-colo.pd

Ciclo inicial de seleção entre e dentro de famílias de meios-irmãos na população de milho CMS 52 nos tabuleiros de Sergipe.

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Amadurecimento de frutos de bananeira BRS Princesa.

A cultura da banana é de extrema importância, de maior consumo a nível mundial, fato embasado na disponibilidade, na aceitação sensorial e no preço da fruta. Muito embora a produção brasileira seja alta, também são observados altos percentuais de perdas póscolheita, resultado de um conjunto de fatores que envolvem o despreparo dos agentes da cadeia de comercialização no manuseio da fruta e do desconhecimento das características de amadurecimento da fruta. Gerar informações sobre o amadurecimento é fundamental para garantir a qualidade da fruta e otimizar sua vida útil pós-colheita

Characterization of different oil soapstocks and their application in the lipase production by Aspergillus niger under solid state fermentation.

Lipases are enzymes that catalyze the hydrolysis of the ester linkage in a triacylglycerol oil-water interface, while in non-aqueous environments they catalyze reverse reactions (esterification, transesterification and interesterification). They can be produced by a solid state fermentation (SSF) process adding value to agro-industrial residues as alkaline soapstocks that can be used as a lipid substrate for lipase production. The objective of this study was to characterize the soapstocks of canola, sunflower and corn and use these byproducts for fungal lipase production using the mutant strain 11T53A14 of Aspergillus niger. The work was carried out following 24-1 and 23 experimental designs in the presence and absence of inducers, respectively, aiming to evaluate the influence of some variables in the lipase production. The production by SSF was carried out in aerated columns incubated at 32°C. Among the soapstocks evaluated, the sunflower soapstock was the best inducer for enzyme production, with 201 U/gdm (gram of dry medium) using 108 spores/gm (gram of medium) inoculated on wheat bran humidified with 80 mL of liquid (ammonium sulfate solution) that corresponds to a final concentration of 0.5% nitrogen, and 3% inducer. The best lipase activity obtained without soapstock was 182 U/gdm under the same processing conditions as the experiment using soapstock. Although the results with the highest lipase activity with sunflower soapstock and without inducer are close, the Tukey test showed a significant difference of these results, which proves the importance of lipid substrate to improve the lipase activity