955 resultados para Value-added tax


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In this work a solar drying system for food dehydration was developed. It is a direct exposition drying apparatus that uses solar energy to heat the circulating air. First, the construction and assembly of this apparatus was described, in which was used scrap wraps of used tires for thermal insulation, allowing the reuse of solid waste, being an ecologically correct recycling option. After, the results obtained in experiments for cashew drying showed the thermal and economical feasibility of the proposed solar drying system, focusing on the process of flour production and in its chemical characterization. It was also demonstrated the social importance of this production for socially excluded people, since the value added to this fruit, in relation to its in nature form, may represent an option for job and income generation. The main features of the proposed dryer are its low cost and its easy fabrication and assembly process. After cashew drying, the obtained product was processed into flour by using a knife mill and it was added crushed rapadura to reduce the rancid taste caused by tannin

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It presents a direct exposure to solar dryer for drying of food, built from a scrap of luminaire. The dryer works under direct exposure to natural circulation. Will be presented their methods of construction and assembly of that dryer that allows the reuse of materials, constituting a environmentally correct recycling dryer main features proposed are its low cost and simple manufacturing processes and assembly. Test results will be presented for the drying of foods that prove the feasibility and cost of thermal solar drying alternative system proposed. It is worth emphasizing the social importance that such application is for the most excluded since the value-added fruits, vegetables, legumes and other foods in relation to fresh may represent an option of income generation. It will also study the transformation of some of dry food meal and demonstrated that the drying times for the foods tested are competitive and sometimes pointed in the solar literature

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Solid substrate cultivation (SSC) has become an efficient alternative towards rational use of agro industrial wastes and production of value-added products, mainly in developing countries. This work presents the production and functional application results of phenolic extracts obtained by solid substrate cultivation of pineapple (Ananas comosus L.) and guava (Psidium guajava L.) residues associated to soy flour and bioprocessed by Rhizopus oligosporus fungus. Two experimental groups were tested: (1) 9g of fruit residue and 1g of soy flour (A9 or G9); (2) 5g of fruit residue and 5g of soy flour (A5 or G5). After SSC, 100ml of distilled water was added to each Erlenmeyer flask containing 10g of bioprocessed material in order to obtain the phenolic extracts. Samples were taken every two days for total phenolic concentration (TPC) and antioxidant capacity evaluation by DPPH test during 12-day cultivation. The 2-day and 10-d ay extracts were selected and concentrated by ebullition until 1/10 of original volume was reached. After that, both non-concentrated and concentrated extracts were evaluated for their antimicrobial activity against Staphylococcus aureus and Salmonella enterica and a-amylase inhibitory capacity. It was observed an inverse relationship between total phenolic concentration (TPC) and antioxidant capacity during the cultivation. Besides that, the concentrated pineapple samples after two days were able to inhibit both pathogens tested, especially S. aureus. Guava concentrated extracts after 2 days showed expressive inhibition against S. enterica, but negative results against S. aureus growth. When it comes to a-amylase inhibition, A9 extracts after 2 days, both concentrated or not, completely inhibited enzyme activity. Similar behavior was observed for G9 samples, but only for concentrated samples. It was shown that concentration by ebullition positively affected the enzymatic inhibition of G9 and A9 samples, but on the other side, decreased antiamylase activity of A5 and G5 samples

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Over the years, grinding has been considered one of the most important manufacturing processes. Grinding is a high precision process, and the loss of a single workpiece in this stage of the production is unacceptable, fir the value added to the material is very high due to many processes it has already undergone prior to grinding. This study aims to contribute toward the development of an experimental methodology whereby the pressure and speed of the air layer produced by the high rotation of the grinding wheel is evaluated with and without baffles, i.e., in an optimized grinding operation and in a traditional one. Tests were also carried out with steel samples to check the difference in grinding wheel wear with and without the use of baffles.

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A catalyst of great interest to the scientific community tries to unite the structure of ordered pore diameter from mesoporous materials with the properties of stability and acid activity to microporous zeolites. Thus a large number of materials was developed in the past decades, which although being reported as zeolites intrinsically they fail to comply with some relevant characteristics to zeolites, and recently were named zeolitic materials of high accessibility. Among the various synthesis strategies employed, the present research approaches the synthesis methods of crystallization of silanized protozeolitic units and the method of protozeolitic units molded around surfactant micelles, in order for get materials defined as hierarchical zeolites and micro-mesoporous hybrid materials, respectively. As goal BEA/MCM-41 hybrid catalysts with bimodal pore structure formed by nuclei of zeolite Beta and cationic surfactant cetyltrimethylammonium were developed. As also was successfully synthesized the hierarchical Beta zeolite having a secondary porosity, in addition to the typical and uniform zeolite micropores. Both catalysts were applied in reactions of catalytic cracking of high density polyethylene (HDPE), to evaluate its properties in catalytic activity, aiming at the recycling of waste plastics to obtain high value-added raw materials and fuels. The BEA/MCM-41 hybrid materials with 0 days of pre-crystallization did not show enough properties for use in catalytic cracking reactions, but they showed superior catalytic properties compared to those ordered mesoporous materials of Al-MCM-41 type. The structure of Beta zeolite with hierarchical porosity leads the accessibility of HDPE bulky molecules to active centers, due to high external area. And provides higher conversion to hydrocarbons in the gasoline range, especially olefins which have great interest in the petrochemical industry

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