Ce travail fait référence à un procédé automatisé pour l'élaboration du pain de sucre à partir du jus de canne à sucre. Les caractéristiques du produit traditionnel sont maintenues tout en veillant à conserver ses qualités intrinsèques qui en font un aliment naturel, peu altéré par ce procédé technique. Un procédé semi-continu a été développé pour élaborer le pain de sucre. Le procédé se subdivise en 3 étapes principales : l'extraction du jus de canne, l'épuration et la concentration du jus, enfin le moulage du pain de sucre. La dureté et la texture du produit fini sont les paramètres majeurs qui conditionnent la qualité du produit. Les fluctuations des concentrations en sucres réducteurs directs SRD influent significativement sur les paramètres dureté et texture. Ces derniers demeurent les indicateurs majeurs de critère de qualité du pain de sucre. Cette étude est un descriptif détaillé du procédé d'élaboration du pain de sucre dont la qualité dépend étroitement de la concentration en SRD tout au long de la chaîne de fabrication. Les corrélations entre les concentrations SRD et les paramètres qualité y sont également développés.
The phosphate series of Sidi Chennane (Morocco) is frequently affected by sterile bodies called “disturbances” causing many problems during the mining operation. The quantification of these bodies is thus considered as a crucial step for the OCP mining engineers. In following this research, we propose the fractal dimension as a new and simple efficient tool to analyze the disturbed areas. The work was carried out on geoelectrical maps of a study area of 50 hectares located in the northern part of the Sidi Chennane deposit. Fractal dimension was used as a representative parameter for examining the disturbed areas by using the box-counting method. The end result shows a strong linkage between the rate of the disturbances and the corresponding fractal dimension. This may have an important implication to quantify the disturbances and get a precise phosphate reserves estimate.
Recovering and purifying organic solvents during chemical and pharmaceutical synthesis has great economic and environmental importance. Water-alcohol mixture pervaporation was investigated using a pervaporation cell and hydrophobic membranes. This work studied polydimethylsiloxane (PDMS) membrane performance and hydrophobic membranes for removing propanol from aqueous mixtures. PDMS is recognised as being alcohol permselective during pervaporation. It was also observed that water was transferred through a hydrophobic membrane as water’s molecular size is smaller than that of propanol. A laboratory-scale pervaporation unit was used for studying this membrane’s separation characteristic in terms of pervaporation flux and selectivity for feeds containing up to water mass and 30°C-50°C. Total propanol/water flux was observed to vary as operating temperature increased. Although PDMS membranes presented good characteristics for separating water/propanol mixtures, the separation factor and pervaporation flow decreased as water content in the feed increased. The tested membrane was found to be very efficient for water concentrations of less than 0.3, corresponding to total flux transfer maximum.
This work analyses and models the dehydration kinetics for whole and sliced strawberries during freeze-drying. A Virtis 35L Gardiner lyophyliser was used. Freeze-drying was carried out at various hotplate temperatures and several product thicknesses. It was observed that increasing hotplate temperature from 30°C to 70°C during the course of freeze-drying led to reducing the process from 48h to 36h for whole strawberries and from 12h to 8h for the slices, stable dry products being obtained. Studying several strawberry freeze-drying parameters showed that temperature has an important effect on reducing the process’ duration. It lowers the process’ cost whilst preserving dry fruit quality, thereby opening up the field by applying this technology to treating new food products.
RESUMENEs posible diseñar filtros pasa bajos y pasa bandas por medio de una combinación de funciones tangente hiperbólica en el dominio de la frecuencia, usando los teoremas de escalamiento y deslizamiento de las transformadas de Fourier. Las funciones de filtro correspondientes en el dominio del tiempo pueden ser derivadas analíticamente a partir de las expresiones en el dominio de la frecuencia. Los parámetros de suavidad controlan las pendientes en las regiones de corte y permiten la construcción de filtros relativamente pequeños al mismo tiempo que reducen las oscilaciones de la respuesta del filtro en el dominio del tiempo. Se pueden elegir diferentes parámetros de suavidad para las frecuencias de corte alta y baja en el diseño de filtros pasa banda. Siguiendo el esquema propuesto en este artículo se pueden derivar fácilmente los otros tipos de filtro.Palabras claves: filtro digital; fosfato; hiperbólico; Marruecos; resistividad ABSTRACT Low-and band-pass filters can be designed by a combination of hyperbolic tangent functions in the frequency domain using the scaling and shifting theorems of the Fourier transforms. The corresponding filter function in the time domain can be derived analytically from the frequency domain expression. The smoothness parameters control the slopes at the cut off regions and permit the construction of a relatively short filter while reducing the oscillations of the filter response in the time domain. Different smoothness parameters can be chosen for the low and high cut off frequencies in the band-pass filter design. Following the proposed scheme can easily derive the other type of the filters.
Actually, the world's car production is constantly on the increase. Approximately 2.9 cars are produced and sold every second, which is mainly linked to the strong demand for cars in a flourishing market all over the world. Nowadays, the car stands for an essential tool in the daily life of man (vehicle sales in world markets reached 90.68 million in 2015 and 89.7 million in 2014). Consequently, there has been rapid growth in terms of the implantation of automotive production plants with a view to meeting the market needs. However, this very motor vehicle production currently faces huge challenges, the most important of which are related to environmental issues and how manufactures can produce a sustainable and profitable industry for the future (through adopting more environmentally-friendly technologies such as the use of more sustainable fuel resources and new types of modular design with built-in reclability).Our study will mainly emphasize life cycle assessment (LCA) of a headrest for an automotive seat in Morocco. That is to say, this study is based upon the requirements of the ISO 14040 standards by means of OpenLCA software. Besides, this study aimed at evaluating the environmental impacts while adopting the CML 2001methodology in order to assessing the impacts of the manufacturing process of a headrest (raw material, cutting, sewing and injection). Therefore, this study will enable us to evaluate different environmental impacts, including ecology, toxicology, ecotoxicology and the depletion of natural resources. What is more, system boundary was fixed on the product manufacturing process (ranging from receipt the raw material to the final product) and the functional unit was selected as 1 headrest. As it turns out, the greatest environmental impact has been associated with the injection process, but, on reflection, we concluded that the manufacture of headrests for a car has negative environmental impacts. Accordingly, this study can be generalized with the aim of evaluating the impact of any headrest being manufactured anywhere in the world.
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