Síntese e caracterização de poliestireno sulfonado

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Fragilidade financeira externa é os limites da política cambial no real

This article assesses the impacts of Brazil's exchan e- based stabilization plan (Plano Real) on Sexternal financial fragility and discuss exchange policy to Overcome the Br vulnerability. In order to the country's es alternative azil's external do so, we have developed an index for this external financial fragility, which is applied to a time series of foreign sector variables from 1992 to 1997. The evidences show that Brazilian external financial fragility has grown during the first three years and half after the Real Plan, particularly in 1996 and 1997. Using this evidence, the paper questions the effectiveness the of government's adjustment strategy for the industrial sector, based on four pillars: price stabilization, capital trade and liberalization and exchange appreciation. we Finally, conclude that the scope for changes in currently exchange policy is too small: the government is prisoner of a self-inflicted “exchange trap”.Este artigo avalia os impactos do plano de estabilização brasileiro (Plano Real) sobre a fragilidade financeira externa do país e discute as propostas de mudanças na política cambial com vistas à superação do quadro de vulnerabilidade externa. Para tanto, é desenvolvido um índice de fragilidade financeira externa, que é aplicado a uma série de dados relativos a variáveis do setor externo no período de 1992 a 1997. As evidências mostram que a fragilidade financeira externa no Brasil cresceu bastante durante os primeiros três anos e meio do Plano Real, em particular em 1996 e 1997. Com base nesta evidência, o texto questiona a eficácia da estratégia de reestruturação produtiva do governo para o setor industrial, baseada no tripé estabilização, abertura comercial e de capitais e apreciação cambial. Por fim, conclui-se que o raio de manobra para alteração da política cambial em vigor é bastante estreito, estando o governo prisioneiro da “armadilha do câmbio”, que ele mesmo criou

Eggshells as agro‐industrial waste substitute for CaCO3 in glass foams: A study on obtaining lower thermal conductivity

In this work, discarded glass bottles (GB) and eggshells (ES) were used to produce foam glass designed for thermal insulation. The literature on the thermal conductivity of foam glasses produced with eggshells is sparse. This material was used as pore‐forming agent at 3% and 5% weight fractions to obtain a foam glass with low thermal conductivity. Homogenized powders were uniaxially pressed, and the compacts were fired at three temperatures (800, 850, and 900°C). Raw materials were characterized by chemical analysis and particle size distribution. The foam glasses were characterized by their porosity, phases, compressive strength, and thermal conductivity. The best insulating properties were obtained for the composition containing 5 wt% ES fired at 800°C. This sample displayed a porosity of 91.4% while its thermal conductivity was of 0.037 W/m.K, with a compressive strength of 1.12 ± 0.38 MPa. Crystalline phases were observed in samples fired at 850 and 900°C as a result of the devitrification process. The final properties of the materials are comparable to those of commercial foam glasses obtained from non‐renewable, more expensive raw materials, a great indicator that the studied compositions could be used as an environmentally friendly substitute

Conventional currency crises models, speculative attack and the reform of the international monetary system : a Fost-Keynesian approach

This paper develops a critical view of the conventional currency crises models from a Post Keynesian perspective. Besides, it also presents a Post Keynesian proposal to reform the international monetary system, based on Keynes’s ideas and Davidson’s works.Indisponível

Obtenção de polianilina sulfonada através do ácido cloro sulfônico

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Obtaining bioabsorable scaffolds from PLGA and IR blend with the addition of hydroxyapatite

A obtenção de scaffolds bioativos a partir da blenda polimérica de poli (ácido láctico-co-glicólico) (PLGA) e poliisopreno (IR) com diferentes adições de Hidroxiapatita (HAp) é proposta como uma alternativa à engenharia de tecidos. Para o preparo das soluções poliméricas, a blenda de PLGA/IR e a HAp foram dissolvidas em clorofórmio. Posteriormente, o scaffold foi processado por electrospinning, variando-se a distância entre a seringa e o coletor. As amostras foram caracterizadas quanto a composição química e estrutural por potencial zeta, difração de raios-X (DRX) e espectroscopia de infravermelho por transformada de Fourier (FTIR). Para avaliação da morfologia usou-se a microscopia eletrônica de varredura (MEV) e para o comportamento citotoxicológico utilizou-se a metodologia de analises de viabilidade celular. O valor de potencial zeta da HAp foi de -22 mV e o FTIR e DRX foram condizentes com a literatura. As imagens de MEV permitiram a análise do tamanho médio e desvio padrão das fibras obtidas, comprovando uma diferença significativa entre as amostras. O ensaio de citotoxicidade mostrou que o produto obtido é biocompatível, porém as amostras com menor formação de fibras são menos biocompatíveis. Os resultados demonstraram a ampla influência da distância entre o coletor e a ponta da seringa e da relação blenda/HAp, sendo que o scaffold obtido com a maior distância coletor/seringa e maior relação HAp/blenda apresentou fibras com tamanho médio menores e maior homogeneidade e baixa citotoxicidade celular.The aim of this paper is the obtainment of bioactive scaffolds from poly (lactic acid-co-glycolic acid) (PLGA) and polyisoprene (IR) polymer blends with different additions of hydroxyapatite (HAp) as an alternative for tissue engineering. For the preparation of the polymer solutions, the PLGA/IR blend and the HAp were dissolved in chloroform. Subsequently, the scaffold was processed by electrospinning, varying the distance between the syringe and the collector. Scaffolds chemical and phase composition were characterized by zeta potential, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to evaluate the morphology and for the cytotoxic behavior the cellular viability analysis methodology was used. The zeta potential value of the HAp was -22 mV and the FTIR and XRD were consistent with the literature. The SEM images allowed the analysis of the mean size and standard deviation of the obtained fibers, demonstrating a significant difference among the samples. The results showed the great influence of the distance between the collector and the tip of the syringe and the blend/HAp ratio, and the scaffold obtained with the largest collector/ syringe distance and the highest HAp/blend ratio showed fibers with a smaller mean size and greater homogeneity and low cellular cytotoxicity

EFFECT OF DILATATION OF THE CEREBRAL VENTRICLES AFTER THE ADMINISTRATION OF NITROXYNIL IN SWISS ALBINE MICE DURING ORGANOGENESIS

SUMMARY: Nitroxynil 34% is an anthelmintic of the family of phenolic substitutes that is used for the control ofSUMMARY: Nitroxynil 34% is an anthelmintic of the family of phenolic substitutes that is used for the control o

Anomalous loss hysteresis loop

This paper discusses the anomalous loss behavior in two electrical steels types. Starting from a non oriented electrical steel coil, three groups of samples with different grain sizes were produced. Grain oriented steel samples were produced from a commercially available material. The experimental procedure was performed by means of magnetic properties measurements using an Epstein frame. A procedure to draw the hysteresis curve of the anomalous loss is proposed. The results reported that anomalous loss has a different behavior when the two electrical steel types are compared. In non oriented steels anomalous loss is concentrated at the low induction region. In grain oriented steels, a remarkable participation of high induction region is observedIPTCAPE