Simulation of biomass gasification in circulating fluidized bed reactor by aspen plus

Biomass is the fourth largest source of energy in the world. Many consider it to be the best option, with the greatest potential as an alternative energy supply which meets energy requiremen ts, for ensuring future fuel supply. Biomass energy resources are potentially the world's largest and most sustainable energy source, a renewable resource comprising 220 billion oven-dry tons (about 4500 EJ) of annual primary production [1]. lt is currently assumed that 5% of this energy could be mobilized to produce energy, i.e. a total of 225 EJ representing an energy equivalent ofmore than 5 billion tons ofoil equivalent, accounting for almost 50% ofthe world's total primary energy demand at present [2]. Hydrogen production is one of the most promising alternative energy technologies . The majority of experts consider that hydrogen has a significant role to play as an important energy carrier in the future energy sector [3]. Howe ver, it is a secondary form of energy that, like electricity, must be manufactured. A promising way to generate hydrogen is by thermochemical conversion of biom ass to synthe sis gas , consisting of a mixture of H2, CO, C0 2, CH.i, 0 2, N2 and tar. ln order to maximize H2 yield, an Or steam circulating fluidized bed (CFB) gasification process was proposed. For this purpose a computer simulation model was developed using the commercial chemical process simulator ASPEN Plus.N/

On the random neighbor Olami-Feder-Christensen slip-stick model

We reconsider the treatment of Lise and Jensen (Phys. Rev. Lett. 76, 2326 (1996)) on the random neighbor Olami-Feder-Christensen stik-slip model, and examine the strong dependence of the results on the approximations used for the distribution of states p(E).Comment: 6pages, 3 figures. To be published in PRE as a brief repor

Immunohistochemistry studies on bovine squamous cell carcinoma morphological characterization of epidermal cell proliferation and differentiation markers and characterization of cytokeratins

Bovine Ocular Squamous Cell Carcinoma (OSCC) is a general designation for a group of primary neoplasias of keratinocytes arising from ocular tissues, especially the lids and particularly the third eye lid. OSCC has been diagnosed all over the world with high prevalence, being the most common bovine tumour and the one causing the most significant economic losses (Hamir & Parry, 1980; Dennis et al., 1985, Heeney & Valli, 1985; Wilcock, 1993). In Portugal, the frequency of these tumours is particularly high in the Azores, where in S. Miguel Island a large number of cattle affected with OSCC is rejected for consumption at slaughter. OSCC is the second most frequent neoplasia after urinary bladder tumours, representing 21% of all cases of rejection due to neoplasia (Pinto et al, 1996). Several reasons have been advanced to explain this situation namely the fact that animals stay in pasture all year around, with a prolonged exposition to day light and benefiting from few shelters. The ingestion of toxic plants present the pasture could also give rise to photosensitazation problems, either primary or due to hepatic toxicity, that could generate predisposing conditions to the development of OSCC

MILIARY TUBERCULOSIS IN THE XXI CENTURY – A CASE REPORT

Introdução: Atualmente, a tuberculose ainda representa um sério problema de saúde pública. A idade precoce e a infeção VIH constituem importantes fatores de risco para doença grave ou disseminada. Caso clínico: Apresentamos o caso de uma menina de três anos de idade observada por febre prolongada sem foco infecioso evidente ao exame físico. O estudo analítico inicial foi sugestivo de infeção urinária, pelo que iniciou antibioticoterapia empírica. A urocultura confirmou esse diagnóstico, mas a febre persistiu. Na investigação complementar, a radiografia torácica revelou um infiltrado pulmonar com padrão miliar. O Mycobacterium tuberculosis foi isolado no aspirado gástrico, líquor e urina. Iniciou tratamento com antituberculosos e corticóide, com melhoria clínica significativa. Conclusões: Nesta era de tecnologia médica avançada, a tuberculose ainda é um desafio diagnóstico, especialmente quando a apresentação clínica é atípica e extrapulmonar. Um elevado índice de suspeição clínica é fundamental, pois a instituição precoce do tratamento é decisiva para o prognóstico

Using Nonlinear Static Procedures for the Seismic Assessment of Irregular RC Buildings

The application of Nonlinear Static Procedures (NSPs) to assess the seismic vulnerability of existing structures has become widely accepted and extensively used in the literature as well as in engineering practice. Nevertheless, their success in predicting the response of irregular buildings is not yet fully verified. The main goal of the present study is to evaluate the capability and accuracy of some of the existing nonlinear static procedures (N2 and ACSM, in this case) to estimate the seismic performance of irregular structures. In order to accomplish this objective, four existing buildings, irregular in plan and elevation, were subjected to an extensive number of nonlinear static and dynamic analyses. The comparisons, focused on both global and local response parameters provide first indications on the reliability of static procedures to estimate the actual response of irregular RC buildings.N/

Genetic purity certificate in seeds of hybrid maize using molecular markers.

Um dos principais atributos que conferem à semente uma alta qualidade é sua pureza genética, sendo a principal causa de contaminação em sementes de milho híbrido, a ocorrência de autofecundação do parental feminino. No entanto, ainda não existem metodologias seguras e rápidas para detectar tais contaminações. Desta forma, o presente trabalho foi desenvolvido objetivando certificar a pureza genética em sementes de milho híbrido por meio de diferentes técnicas de marcadores bioquímicos e de DNA. Sementes de dois híbridos e de suas respectivas linhagens, provenientes do programa de melhoramento da Universidade Federal de Lavras foram avaliadas por padrões eletroforéticos das isoenzimas álcool desidrogenase (ADH), esterase (EST), fosfatase ácida (ACP), glutamato-oxalacetato transaminase (GOT), malato desidrogenase (MDH), isocitrato desidrogenase (IDH), 6-fosfoglucamato desidrogenase (PGDH), fosfoglucomutase (PGM), catalase (CAT) e ß-glucosidade (ßGLU) e por marcadores microssatélites. Os sistemas enzimáticos que permitiram separar os híbridos de seus respectivos progenitores foram a catalase, a isocitrato desidrogenase e a esterase, sendo que para a esterase foi observada segregação mendeliana para o híbrido UFLA 8/3, o que torna a certificação da pureza genética mais segura. Os microssatélites além de terem sido eficientes na diferenciação dos híbridos e das linhagens parentais, apresentaram-se como uma técnica de análise rápida, precisa e independente do ambiente. Como o padrão de amplificação dos microssatélites não foi influenciado quando se utilizou o DNA extraído de sementes inteiras ou de folhas, torna-se possível a utilização de sementes como fonte de DNA, o que acelera e facilita a execução das análises de pureza genética. One of the main features that confer high quality to the seed is its genetic purity, in which one of the major causes of contamination is the self-pollination of the female parent. Up to date, there is no accurate and fast methods for detecting such contamination. Thus, this work was carried out to certify the genetic purity in seeds of hybrid maize using different biochemical and DNA-based markers. Two single-cross hybrids and their parental lines derived from the maize breeding program at UFLA were evaluated by isoenzymatic pattern of alcohol dehydrogenase (ADH), esterase (EST), acid phosphatase (ACP), glutamate-oxaloacetate transaminase (GOT), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH), phosphoglucomutase (PGM), 6-phosphoglucomate dehydrogenase (PGDH), catalase (CAT) and ß-glucosidade (ßGLU) and by microsatellites markers. The enzymatic systems that were able to distinguish the hybrids from their parental line were the catalase, the isocitrate dehydrogenase and the esterase. The esterase showed a Mendelian segregation pattern for UFLA 8/3 hybrid, that enables a safer genetic purity certificate. Microsatellites were able to differentiate the hybrid lines and the respective parental lines. Moreover, this technique was fast, precise and without environment effects. For microsatellites, the amplification pattern was identical when young leaves or seeds were used as DNA source. The possibility of using seeds as DNA source would accelerate and facilitate the role process of the genetic purity analysis

Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin

This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70&thinsp;kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivity was driven by the synergy of two mechanisms operating in different seasons: (i) enhanced productivity in the upwelling region during short austral summer events; and (ii) the persistent presence of the Plata Plume Water (PPW) due to prolonged austral winter conditions. We suggest that the upwelling systems in the southern Brazilian margin were more productive during the last glacial period due to the enhanced Si supply for diatom production by high-Si thermocline waters preformed in the Southern Ocean. We hypothesize that orbital forcing did not have a major influence on changes in upwelling during the last glacial period. However, the more frequent northward intrusions of the Plata Plume Water were modulated by austral winter insolation at 60∘&thinsp;S via changes in the strength of alongshore southwesterly winds. After the Last Glacial Maximum, the reduced Si content of thermocline waters decreased upwelling productivity, while lower austral winter insolation decreased the influence of the Plata Plume Water over the southern Brazilian margin, reducing regional productivity.</p

Tricritical behaviour in deterministic aperiodic Ising systems

We use a mixed-spin model, with aperiodic ferromagnetic exchange interactions and crystalline fields, to investigate the effects of deterministic geometric fluctuations on first-order transitions and tricritical phenomena. The interactions and the crystal field parameters are distributed according to some two-letter substitution rules. From a Migdal-Kadanoff real-space renormalization-group calculation, which turns out to be exact on a suitable hierarchical lattice, we show that the effects of aperiodicity are qualitatively similar for tricritical and simple critical behaviour. In particular, the fixed point associated with tricritical behaviour becomes fully unstable beyond a certain threshold dimension (which depends on the aperiodicity), and is replaced by a two-cycle that controls a weakened and temperature-depressed tricritical singularity.Comment: Formatting improved. 7 pages, 2 figures (included). Journal reference adde

Universal Critical Behavior of Aperiodic Ferromagnetic Models

We investigate the effects of geometric fluctuations, associated with aperiodic exchange interactions, on the critical behavior of $q$-state ferromagnetic Potts models on generalized diamond hierarchical lattices. For layered exchange interactions according to some two-letter substitutional sequences, and irrelevant geometric fluctuations, the exact recursion relations in parameter space display a non-trivial diagonal fixed point that governs the universal critical behavior. For relevant fluctuations, this fixed point becomes fully unstable, and we show the apperance of a two-cycle which is associated with a novel critical behavior. We use scaling arguments to calculate the critical exponent $\alpha$ of the specific heat, which turns out to be different from the value for the uniform case. We check the scaling predictions by a direct numerical analysis of the singularity of the thermodynamic free-energy. The agreement between scaling and direct calculations is excellent for stronger singularities (large values of $q$). The critical exponents do not depend on the strengths of the exchange interactions.Comment: 4 pages, 1 figure (included), RevTeX, submitted to Phys. Rev. E as a Rapid Communicatio