919 resultados para THERMAL PERFORMANCE


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The increasing need for starches with specific characteristics makes it important to study unconventional starches and their modifications in order to meet consumer demands. The aim of this work was to study physicochemical characteristics of native starch and phosphate starch of S. lycocarpum. Native starch was phosphated with sodium tripolyphosphate (5-11%) added with stirring. Chemical composition, morphology, density, binding ability to cold water, swelling power and solubility index, turbidity and syneresis, rheological and calorimetric properties were determined. Phosphorus was not detected in the native sample, but the phosphating process produced modified starches with phosphorus contents of 0.015, 0.092 and 0.397%, with the capacity of absorbing more water, either cold or hot. Rheological data showed the strong influence of phosphorus content on viscosity of phosphate starch, with lower pasting temperature and peak viscosity higher than those of native starch. Enthalpy was negatively correlated with the phosphorus content, requiring 9.7; 8.5; 8.1 and 6.4 kJ g-1 of energy for the transition from the amorphous to the crystalline state for the starch granules with phosphorus contents of 0; 0.015; 0.092 and 0.397%, respectively. Cluster analysis and principal component analysis showed that starches with 0.015 and 0.092% phosphorus have similar characteristics and are different from the others. Our results show that the characteristics of phosphate modified S. lycocarpum starch have optimal conditions to meet the demands of raw materials, which require greater consistency in stickiness, combined with low rates of retrogradation and syneresis.

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The objective of this work was to evaluate the performance of Holstein calves in suckling and post-weaning phases, intensively managed during suckling in the absence or presence of hay. Twenty-four male Holstein calves, at an average age of 15 days and initial weight of 43 kg were used in the experiment. The experimental design was completely randomized, consisting of two treatments and six replications. The treatments were as follows: 1) suckling with milk substitute + initial concentrate for calves, ad libitum + temperate grass hay (oat/ryegrass), ad libitum; 2) suckling with milk substitute + initial concentrate for calves, ad libitum. No significant difference was found between treatments for weight gain and feed conversion. However, the supply of hay caused an increase in daily dry matter intake (2.127 vs 1.894 kg). The intake of hay promoted greater stimulus to consumption of concentrate and greater weight at weaning.

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O objectivo deste artigo é investigar a relação entre a divulgação de informação ambiental nos relatórios e contas anuais e a performance financeira no mercado de capitais das empresas cotadas em Portugal. Para tanto, é usada uma amosta de 35 empresas não financeiras cotadas no mercado de cotações oficiais da Euronext Lisboa no período de 5 anos compreendido entre 2000 e 2004. Os resultados empíricos obtidos sugerem que as empresas que não divulgam informação ambiental têm uma performance financeira – rendibilidade, risco e rendibilidade ajustada ao risco – superior às que o fazem. Em particular, as empresas que apresentam um melhor relato ambiental, divulgando informação ambiental qualitativa e quantitativa, são as que apresentam pior performance financeira. Contudo, as diferenças encontradas ao nível da performance financeira não são estatisticamente significativas. Estes resultados são robustos às duas metodologias usadas: estudos de carteira e tabelas de contingência.

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This paper investigates the performance, investment styles andmanagerial abilities of French socially responsible investment (SRI) funds investing in Europe during crisis and non-crisis periods. Our results show that SRI funds significantly underperformcharacteristics-matched conventional funds during non-crisis periods, but match the performance of their peers duringmarket downturns. The underperformance of SRI funds during good economic states is driven by funds that use negative screens, since funds that use only positive screens performsimilarly to conventional funds across differentmarket conditions. SRI and conventional funds showsignificant differences in risk exposures during non-crisis periods but exhibit much more similar investment styles during crises. Furthermore,we find little evidence of significant differences inmanagerial abilities during bad economic states. Yet, during non-crisis periods, SRI and conventional fund managers exhibit significantly different style-timing abilities and these differences are also related to screening strategies.