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[en] The stability of α-, (β+γ)- and δ-tocopherols present in rice bran oil at different heating temperatures has been evaluated. For this purpose, samples of rice bran oil from chemical and physical refining processes in Brazilian industries were studied. The oils were submitted to cabinet drying without air circulation in the absence of light at 100 ºC, 140 ºC and 180 ºC. The samples were taken before heating and after 48, 144, 240, 336, 432, 576, 768, 1008 and 1368h of heating. The analyses of tocopherols were made by high performance liquid chromatography, with a fluorescence detector. It was determined that α-tocopherol was the compound with the fastest degradation rate at the three heating temperatures. The highest degradation rate of tocopherols in both oils occurred at 180 ºC. Among the tocopherols studied, α tocopherol presented the lowest stability, followed by (β+γ)- and δ-tocopherols.
[es]La estabilidad de los tocoferoles α-, (β + γ) - y δ presentes en los aceites de salvado de arroz a diferentes temperaturas de calentamiento fueron evaluadas. Para ello, se utilizaron muestras de aceite de salvado de arroz proveniente de los procesos de refinación química y física de industrias brasileñas. Los aceites fueron sometidos a 100 ºC, 140 ºC y 180 ºC, en cabinas de secado sin circulación de aire, bajo ausencia de luz. Las muestras fueron tomadas antes de la calefacción y después de 48, 144, 240, 336, 432, 576, 768, 1008 y 1368 h de calentamiento. El análisis de tocoferoles fue realizado por cromatografía líquida de alta eficacia, con detector de fluorescencia. Se observó que el α-tocoferol fue el compuesto con degradación más rápida en las tres temperaturas de calentamiento. La mayor tasa de degradación de los tocoferoles, en ambos aceites, ocurrió a la temperatura de 180 ºC. Entre los tocoferoles analizados, α-tocoferol presentó menor estabilidad, seguido por los (β + γ) - y δ-tocoferoles
[en] The presence of flavored olive oils (FOO) on the market represents an answer to an increasing consumer demand for novel and healthy food. This work aims to compare the sensory acceptability and the thermal stability of FOO prepared by mixing different flavors (lemon, onion, garlic, paprika) to an extra virgin olive oil (EVOO) also used as the control sample. 96 Tunisian citizens were involved in a consumer test and the lemon flavored oil was the most liked whereas the least liked was the oil with onion. Samples were subjected to different heat treatments (60 °C, 100 °C, 200 °C for 1, 2, 4, 8 hours) and the flavor addition did not influence the EVOO stability when samples were heated at 60 °C, whereas at 200 °C the FOO with onion and garlic showed higher oxidative stability. The thermo-oxidation process at 60 °C and at 100 °C of the FOOs was not detrimental for the volatile compound markers but the effect was noticeable for all these markers at 200 °C.
[es]La presencia de aceites de oliva con sabor (FOO) en el mercado representa una respuesta a la demanda cada vez mayor de los consumidores de alimentos novedosos y saludables. Este trabajo tiene como objetivo comparar la aceptabilidad sensorial y la estabilidad térmica de FOO preparado mediante la mezcla de diferentes sabores (limón, cebolla, ajo, pimentón) a un aceite de oliva virgen extra (AOVE), utilizado como muestra de control. 96 ciudadanos tunecinos participaron en una prueba de consumo: el aceite con sabor a limón fue el que más gustó, mientras que el que menos gustó fue el de la cebolla. Las muestras se sometieron a diferentes tratamientos térmicos (60 °C, 100 °C y 200 °C durante 1, 2, 4, 8 horas). La adición de saborizantes no influyó en la estabilidad del AOVE cuando las muestras se calentaron a 60 ° C mientras que a 200 °C el FOO con cebolla y ajo mostraron una mayor estabilidad oxidativa. El proceso de termooxidación a 60 °C y a 100 °C de los FOO no fue perjudicial para el marcador de compuestos volátiles, en oposición al efecto a 200 °C que resultó notable para todos estos marcadores.
[en] In Britain, residential properties are predominantly heated using gas central heating systems. Ensuring a reliable supply of gas is therefore vital in protecting vulnerable sections of society from the adverse effects of cold weather. Ahead of the winter, the grid operator makes a prediction of gas demand to better anticipate possible conditions. Seasonal weather forecasts are not currently used to inform this demand prediction. Here we assess whether seasonal weather forecasts can skilfully predict the weather-driven component of both winter mean gas demand and the number of extreme gas demand days over the winter period. We find that both the mean and the number of extreme days are predicted with some skill from early November using seasonal forecasts of the large-scale atmospheric circulation (r > 0.5). Although temperature is most strongly correlated with gas demand, the more skilful prediction of the atmospheric circulation means it is a better predictor of demand. If seasonal weather forecasts are incorporated into pre-winter gas demand planning, they could help improve the security of gas supplies and reduce the impacts associated with extreme demand events. (letter)
[en] In the present work, we consider the use of thermal stores in spacecraft heating systems. The advantages and disadvantages of various approaches to heat storage are compared. The use of heat stores with a melting working material is most promising and practicable at present.
[en] China has become the world’s largest carbon emitter since 2007; thus, reducing future emission has become an arduous task. Calculating energy efficiency fairly is paramount for formulating energy policies, given the different development levels of provinces. This study employed a three-stage data envelopment analysis model that considered environmental constraints to evaluate the energy efficiency of China’s 30 provinces in 2015 and redefined traditional energy efficiency as energy environment efficiency which calculated under environmental constraints. Different factors, such as urban development level and industrial structure in relation to energy environment efficiency, were analyzed. Three main results were obtained. First, the average energy environment efficiency in 2015 was only 0.73, which showed that China has roughly 30% capacity for improvement in the future. Second, stochastic frontier analysis demonstrated that the industrial structure, energy consumption structure, and central heating systems exerted negative impacts, and the level of city design and the degree of openness exerted positive effects on energy environment efficiency. Third, capital, manpower, and the extent of industrial concentration in central and western regions should be increased to improve China’s energy environment efficiency.
[en] An upgraded infrared imaging system has been installed at the stellarator TJ-II as a diagnostic tool of the Neutral Beam Injection heating. Thermographic analysis of the beam-wall interaction areas can be used to estimate the beam power lost through reionization and shine-through mechanisms in Neutral Beam heated plasmas. Three different Regions of Interest inside TJ-II vacuum vessel have been determined whose thermographic analysis will be applied to the study of beam related processes. The optical conditions required for each application have been used to define the specifications of the IR camera. Optimization of the optical design has been carried out by means of the optical simulation code ZEMAX. The IR window size has been increased to maximize the fraction of the field of view that is free from vignetting. The system has been fully commissioned and is now operative, routinely providing thermographic data of the regions of interest during the last TJ-II experimental campaign. The IR diagnostic is described in detail and its applicability to study beam power deposition on different targets is discussed.
[en] The phase change temperature and latent heat of binary paraffin and fatty acid mixtures were measured using a differential scanning calorimeter. 18 types of samples were found to be suitable for passive walls with phase change temperature ranging from 20 °C to 30 °C. In addition, fifteen types of samples were found suitable for active heating floors or walls with a phase change temperature of 30 °C to 40 °C. Five thousand thermal cycling tests were performed on six representative samples. Based on the experimental results, the average change rates of the phase change temperature of paraffin and fatty acid mixtures were found to be less than 5% and 1%, respectively. These phase change materials exhibited good thermal stability, and the thermal stability of fatty acids was better than that of paraffin mixtures. The appropriate proportions of phase change materials for passive phase change walls and active phase change floors or wall was obtained. (paper)
[en] This study was conducted in order to assess the exposure to bacterial and fungal bioaerosols in the air of waterpipe cafés (AWPCs), in the hose of waterpipe (HWP), and in the water bowl of the waterpipe (WBWP) and to investigate the factors influence increasing the contamination levels in waterpipe cafés in Ardabil. From all the 50 cafés studied, the samples were taken from air and from water contained in water bowl and hose for bacterial and fungal analyses. The results demonstrated that the mean numbers of bacteria and fungi in the indoor air of café, hose, and water bowl were 33.90 ± 14.86 and 25.24 ± 1.99 CFU/m3, 72.16 ± 29.55 and 72.78 ± 42.45 CFU/plate, 53.7 ± 25.46 and 25.26 ± 13.94 CFU/ml, respectively. The predominant bacterial genera in waterpipe cafés were Pseudomonas and Bacillus in air, Staphylococcus and Pseudomonas in the hose, and Staphylococcus and Pseudomonas in the water bowl, respectively. The predominant fungal species in waterpipe cafés were Penicillium and Cladosporium in air, yeast and Fusarium in the hose, and Paecilomyces and yeast in the water bowl, respectively. The results of statistical analysis showed that there was a significant relationship between the mean concentrations of bacterial aerosol and qualitative variables such as type of heating system, materials of wall and ceiling, traditional restaurants, interior supermarkets, moisturized walls, the number of people, area of cafés, and temperature. But there was no significant relationship between these variables and the mean concentration of fungal aerosols. The results also showed that the levels of bioaerosols were high in the air, hose, and water bowl of the waterpipe. Therefore, cafés can be a potential source for the transmission of pathogenic agents and increase the risk of respiratory diseases among waterpipe smoking individuals.
[en] Energy conservation continues to play a crucial role in social and economic development. With the remarkable increase in oil prices and exploring solutions for the replacement of fossil fuels, an ecofriendly energy resource has become the priority among more and more people. Keeping the intension for reducing the global warming impact and looking for alternative clean source of energy, solar energy applications such as solar thermal systems, solar water heating and cooling are becoming energy-efficient designs. One of the widely used applications of solar energy is solar water heating systems. Low-cost solar water heaters can cover the domestic needs for water in the range of 100–200 l per day. Solar water heating systems are generally more efficient and advantageous in hot areas. However, the application of solar water heating is still a challenge in winter and sub-zero conditions, having low solar irradiance. In such conditions, solar water heating system cannot produce enough energy, which drives a need for evaluating system component design and improves its performance during low ambient conditions. In this study, detailed design methods for solar water heater components are discussed for cold regions like North Dakota, USA. The type of system chosen in this study is natural circulation-based solar water heating system. The study will also compare the experimental data with previously conducted numerical analysis.
[en] The responsibilities of ITER-India include a mix of precision, heavy, R and D intensive and interface intensive systems, under the built-to-print and functional systems categories. In several systems, the components are the first or largest of their kind. The uniqueness of component specifications and adherence to the desired quality standards considering the harsh nuclear environment in which the components need to operate and survive the lifetime of ITER leads to a challenging situation—namely that neither the existing laboratories nor potential suppliers have ever done or encountered such a scale-up (either in size, capacity, precision, quality etc) and in many cases do not have even the research and development (R and D) infrastructure to match ITER’s requirements. To bridge this gap, ITER-India adopted a two-step approach of first manufacturing prototypes as per ITER-specific standards and then subjecting them all to critical evaluation before launching bulk production. Some of the key areas of development include demonstrations of the following: (a) 1.5 MW radiofrequency power in the 35–65 MHz frequency range under Diacrode and Tetrode tube technologies for the ion cyclotron resonance heating system; (b) a low loss multi-process pipe cryogenic transfer line and the development of a 3.3 kg s−1 cold circulator for the cryoline and cryo-distribution system; (c) an angled accelerator grid with precision in positioning of apertures within 50 μm, as a first of its kind development, and special, ITER grade, copper alloy development for the diagnostic neutral beam (DNB) system. Full scale test facilities have been built for the performance assessment of the DNB, the electron cyclotron and ion cyclotron sources, cryogenic transfer lines and diagnostics systems. A summary is presented of the technical features of the major areas of procurements, notable achievements in R and D and manufacturing and their application in the Indian R and D related to fusion. (paper)