Food and biofuel: a possible dialogue? An overview about brazilian ethanol context.

Tropentag 2015

Estudo de secções verticais do sistema Cu-Li-Mg por calorimetria diferencial de varrimento

O sistema Cu-Li-Mg só foi, até ao momento, alvo de estudos por Melnik et al.que, com base nos resultados de ensaios de DRX, definiram a secção isotérmica a 643 K;a única fase ternária detectada corresponde à estequiometria Cu8Li2Mg15. No presentetrabalho, começou por se desenvolver um estudo, em DRX e MEV/EDS, que permitiuconfirmar a existência daquela fase ternária à temperatura ambiente. Além disso, foidesenvolvida uma primeira modelização que relaciona os valores experimentais obtidos eos de Melnik et al. com a energia de Gibbs das fases que constituem o sistema.Reconhecido o facto dos valores experimentais serem manifestamente escassos e nãocobrirem temperaturas próximas da curva de liquidus, afigurou-se necessário desenvolverestudos em CDV/ATD. Assim, foram feitas experiências em ATD de fluxo contínuocom amostras correspondentes a três secções verticais. Os resultados obtidos para asecção vertical relativa a xLi 0.05 foram comparados com a modelização dessa mesmasecção.The Cu-Li-Mg was, until this moment, been just studied by Melnik et al. These authors hadstudied the system by XRD at 643 K. The only ternary compound they have found wasCu8Li2Mg15. In the present work weve started by studying the system by means of XRD andSEM/EDS and we were able to confirm the existence of Cu8Li2Mg15. Besides that, it was developed a first assessment that relates our experimental work and the one from Melnik et al.with the Gibbs energies of the phases that constitute the system.As the experimental work was still not enough to assess the ternary at all range of temperatures,specially near liquidus, we have done some measurements on DTA/DSC with samplescorresponding to three vertical sections. The results obtained for xLi 0.05 were compared withthe assessed vertical section

The experimental study of the Bi-Sn, Bi-Zn and Bi-Sn-Zn systems

The binary BiSn was studied by means of SEM (Scanning Electron Microscopy)/EDS (Energy-Dispersive solid state Spectrometry), DTA (Differential Thermal Analysis)/DSC (Differential Scanning Calorimetry) and RT-XRD (Room Temperature X-Ray Diffraction) in order to clarify discrepancies concerning the Bi reported solubility in (Sn). It was found that (Sn) dissolves approximately 10 wt% of Bi at the eutectic temperature. The experimental effort for the BiZn system was limited to the investigation of the discrepancies concerning the solubility limit of Zn in (Bi) and the solubility of Bi in (Zn). Results indicate that the solubility of both elements in the respective solid solution is approximately 0.3 wt% at 200 C. Three different features were studied within the BiSnZn system. Although there are enough data to establish the liquid miscibility gap occurring in the phase diagram of binary BiZn, no data could be found for the ternary. Samples belonging to the isopleths with w(Bi) 10% and w(Sn) 5%, 13% and 19% were measured by DTA/DSC. The aim was to characterize the miscibility gap in the liquid phase. Samples belonging to the isopleths with w(Sn) 40%, 58%, 77/81% and w(Zn) 12% were also measured by DTA/DSC to complement the study of BiSnZn. Solubilities in the solid terminal solutions were determined by SEM/EDS. Samples were also analyzed by RT-XRD and HT-XRD (High Temperature X-Ray Diffraction) confirming the DTA/DSC results for solid state phase equilibria

Relationship between the DTA peak and phase diagram : symbiosis between a thermodynamic database and a DTA curve

The shape of a differential thermal analysis (DTA) curve depends on the sample and the reference, the heating or cooling rates used in theexperiment as also the thermal resistance to heat ¯ow from the heat source to the cell containing the sample (or the reference), Ra (Rr).Having access to a database that contains the values of the sample heat capacity, Cp, and those of the enthalpy of transformation, H, andcalculating the parameters that depend on the apparatus, the cells and the reference, as well as the heating rate used, it is possible todetermine the T (Ta ÿ Tr) values through the equationTa ÿ Tr RadHdt RrCrdTrdt ÿ RaCadTadtwhere Ca is the heat capacity of the cell sample system and Cb the heat capacity of the cell reference system. The comparison betweenthe calculated and experimental values for T enables an assessment to be made as to whether the modelled parameters are in agreementwith the experimental information. This procedure enables a deeper perception of the thermal analysis in general and of the apparatus usedin particular

Sistema fotovoltaico isolado de configuração mista para famílias ribeirinhas.

Um sistema fotovoltaico pode apresentar diferentes configurações dependendo do tipo de demanda que se deseja atender. Este trabalho apresenta um sistema de configuração mista que consiste na utilização do mesmo gerador fotovoltaico para alimentar um sistema fotovoltaico isolado com acumulador de energia e um de acoplamento direto. O sistema foi instalado na sede da Associação dos Trabalhadores Agroextrativistas da Ilha das Cinzas, localizada no estuário do Rio Amazonas, em Gurupá ? Pará. Na Ilha, não há energia elétrica convencional e o acesso a serviços de saneamento básico é limitado. Como são sistemas com características diferentes, cada um necessita de uma configuração distintas entre os módulos fotovoltaicos. Para o sistema isolado com acumulação de energia as conexões entre os módulos são três ligações em paralelo de dois módulos em série. Para o sistema de acoplamento direto os seis módulos fotovoltaicos são conectados em série, onde os terminais são conectados a um conversor de frequência que aciona cargas que possuem motor de indução trifásico. A comutação entre as conexões ocorre de forma manual utilizando plugues e soquetes industriais tetrapolares de 32 A. Os terminais dos seis módulos fotovoltaicos foram conectados a três plugues enquanto cada sistema (de acumulação e de acoplamento direto) teve seus terminais conectados a três soquetes. De forma padrão, o gerador fotovoltaico é conectado ao sistema com acumulação de energia, garantindo energia elétrica em períodos sem incidência solar. Quando necessário, as conexões do gerador fotovoltaico serão comutadas manualmente para o sistema de acoplamento direto responsável por acionar cargas com motor de indução trifásico, seja para retirar a polpa do açaí, bombear água para um reservatório, irrigação de plantas ou outra atividade. O sistema misto obteve êxito em comutar as conexões terminais do gerador fotovoltaico de acordo com as demandas energéticas de cada sistema.Anais do Congresso Brasileiro de Energia Solar, 9., 2022, Florianópólis

Can stigma become a resource? The mobilisation of aesthetic–corporal capital by female immigrant entrepreneurs from Brazil

The proportion and visibility of Brazilian women and particularly the specific images of Brazil and Brazilians in the Portuguese imaginary have contributed to the construction of new versions of stigma and stereotypes surrounding them. Mainstream images of Brazilian women have incorporated prejudices about the sensuality of Creole women who are reminiscent of the Portuguese colonial imaginary. Starting from this stigmatised image, we show how Brazilian women entrepreneurs in the ‘beauty’ business filière reinterpret and mobilise this perceived negative image, transforming it into an added value associated with an ‘aesthetic’ Brazilian body culture. This idea of ‘body’ aesthetics becomes a business resource transformed into aesthetic– corporal capital, a key component of the Brazilian beauty business filière. Empirically, this research is based on qualitative elements, in particular 25 interviews with Brazilian women entrepreneurs of the beauty filière working in Portugal, collected for the project BELTS-W (Brazilian Entrepreneurial Links and Transnational Strategies – Women).This article is an output of the Foundation for Science and Technology (FCT) sponsored project PIHM/GC/0111/2008 and Brazilian Entrepreneurial Links and Transnational Strategies-Women (BELTS-W)

Effect of crude protein levels and organic selenium supplementation in the diets fed during the breeding season on reproductive parameters of red-winged tinamous (Rhynchotus rufescens)

There is little information on the nutrition of red-winged tinamous (Rhynchotus rufescens) reared in captivity, and their nutritional requirements still need to be determined. This study aimed at determining dietary crude protein requirements and testing four organic selenium supplementation levels in the diet of red-winged tinamous during the breeding season. Birds were housed in a conventional broiler house divided in 16 boxes with one male and three females each. Iso-energy (2800kcal ME/kg) pelleted feeds, based on corn and soybean meal, were supplied in tube feeders. In the first experiment, treatments consisted of four different diets containing different crude protein (CP) contents (15, 18, 21, or 24%) and in the second experiment, the four diets contained equal protein level (22.5%) and four different organic selenium levels (0, 0.2, 0.4, or 0.8ppm). Data were analyzed by the least square method. The best egg weight and eggshell thickness were obtained with 22.5% dietary CP. Organic selenium did not influence the studied reproductive traits of red-winged tinamous (Rhynchotus rufescens) males or female