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Search Results: 1 - 10 of 220007 matches for " Neyda C. Om Tapanes "
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Hydrolysis - Hydrogenation of soybean oil and tallow  [PDF]
Gisel Chenard Díaz, Rodolfo Salazar Perez, Neyda de la C. Om Tapanes, Donato Alexandre Gomes Aranda, Angel Almarales Arceo
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.37074
Abstract: Hydrolysis reactions are of major importance to the oleochemical industry in the production of fatty acid and their derivates. Hydrolysis of triglyceride from vegetable oil has been studied under various parameters such as: heterogeneous catalyst, temperature, reaction time and agitation speed. During the hydrolysis of soybean oil and tallow using nickel catalysts on alumina support was verified that the glycerol produced worked as hydrogen donor, allowing the hydrogenation of unsaturated fatty acids produced. Maximum conversion was achieved in 3 hours, catalysts 25% NiO/Al2O3, temperature of 250oC and 270oC and 250 rpm.
Production of Hydrogen from Aqueous Phase Reforming of Glycerol: Economic Evaluation  [PDF]
Rodolfo Salazar Pérez, Mariana M. V. M. Souza, Neyda C. Om Tapanes, Gisel Chenard Diaz, Donato A. G. Aranda
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.61003
Abstract:

Glycerol is the main byproduct from the production of biodiesel by transesterification of vegetable oils, and approximately 10% of total biodiesel production volume corresponds to glycerol. The profitability of various chemical processes depends, in part, on the sale of byproducts, which enables a reduction in the production costs and consequently, in the product’s final price. Thus, it is necessary to look for alternatives to solve the problem of glycerol buildup, in order to avoid future environmental impacts and make biodiesel competitive in the growing market of biofuels. In this context, this study’s objective is the development of a low cost and environmental clean technology that allows the conversion of glycerin into a greater value product. In this paper, an economic evaluation of production hydrogen using Aqueous Phase Reforming (APR) was conducted. Firstly, we detailed the technical assumptions in the study. Reactions were performed in batch reformer of 10 liters of capacity, at the temperature of 250℃ and pressure of 38 atm. Finally, a sensitivity analysis was performed. The results from economic evaluation show that APR of glycerol, using nickel catalysts supported on alumina or zirconium oxide, is a promising and competitive technology for hydrogen production.

Hydroesterification of Nannochloropsis oculata microalga’s biomass to biodiesel on Al2O3 supported Nb2O5 catalyst  [PDF]
Angel Almarales, Gisel Chenard, Roberto Abdala, Donato A. Gomes, Yordanka Reyes, Neyda Om Tapanes
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.44031
Abstract: Hydroesterification process has been presented biodiesel production from oil the green microalga Nannochloropsis oculata raw materials. Biodiesel studied in this work is the main product got from the hydroesterification of biomass the Nannochloropsis oculata and was obtained from esterification of fatty acid (product of a hydrolysis reaction) with methanol. It was used as catalyst the niobic acid pure and supported on δ-aluminum. The product was evaluated by gas chromatography and other analyses. The optimum conditions found in the conversion (%) for the hydrolysis reactions of the biomass (92.3%). Better results were observed in the algae concentration 20%, lead at 300?C with 20% of catalyst. For esterification of fatty acids of Nannochloropsis oculata (92.24%), were observed the molar ratio methanol: fat acid 3, lead at 200°C with 20% of catalyst supported.
Influencias de las impurezas en los combustibles residuales
Carlos Losada,Neyda Om Tapanes,Lucrecio Pérez
Ciencia Ergo Sum , 2002,
Abstract: A partir de considerar como campo experimental una planta generadora de electricidad que utiliza motores marinos MAN B&W L+V-28/32H, se demuestra que las impurezas formadas durante el proceso de fabricación, transportación, almacenamiento y consumo del combustible afectan la calidad de combustión y con ello los da os causados a los elementos del sistema.
Tribología y lubricación en ensayo de banco
Carlos Losada,Neyda Om Tapanes,José Rodríguez
Ciencia Ergo Sum , 2001,
Abstract: Se realiza un estudio tribológico de aceites y grasas lubricantes en la "Máquina Shell de 4 Bolas". Se ofrecen resultados para los distintos aceites y grasas, variando las condiciones de prueba para conocer el comportamiento de los valores de desgaste a bajas cargas según el método; se busca hasta qué carga la película de lubricante se mantiene sobre las superficies metálicas de las bolas (sin que ocurra el agripado), y se analiza a qué carga ocurre la soldadura. Con estos ensayos se logra demostrar el comportamiento de distintas formulaciones de aceites y grasas.
BIODIESEL NO BRASIL: MATéRIAS PRIMAS E TECNOLOGIAS DE PRODU O
Neyda de la Caridad Om Tapanes,Donato Alexandre Gomes Aranda,Rodolfo Salazar Perez,Yordanka Reyes Cruz
Acta Scientiae et Technicae , 2013,
Abstract: Since the birth of the environmentalist movement, and, specially after the oil crisis in the 70s, alternative forms of energy have been discussed in order to substitute fossil fuels. One of these alternative fuels, Biodiesel, had its production and consume determined in the form of the law 11.097/05. In this paper, we discuss the current state of the art of Biodiesel in Brazil.
T Regulatory Cells and BCG as a Vaccine against Tuberculosis: An Overview  [PDF]
Om Parkash
World Journal of Vaccines (WJV) , 2015, DOI: 10.4236/wjv.2015.52012
Abstract: Bacille Calmette Guerin (BCG), which has been used since 1921 as the only vaccine against tuber-culosis (TB), protects poorly, if at all, against pulmonary tuberculosis among adults in high incident developing countries. This failure has been attributed to the possible down modulating action of T regulatory cells (Tregs), which can be stimulated by environmental mycobacteria and expanded by BCG vaccination. Tregs induced at the site of BCG vaccination may interfere with protection against tuberculosis. This communication describes the contribution of Tregs towards dampening the efficacy of BCG and plausible approaches to countering this down modulating effect of Tregs. Probably, antigen specific inhibition of the local recruitment of Tregs whilst avoiding generalised disturbance of immune homeostasis could prove to be worthwhile. Alternatively, drugs with short half life may achieve more acceptable transient inhibition of Tregs function than the prolonged action of monoclonal antibodies. Evolving novel safe strategies is a challenge for developing a better anti TB vaccine.
Crystallization Behavior and Microstructural Analysis of Lead-Rich () Glass Ceramics Containing 1mole
C. R. Gautam,Devendra Kumar,Om Parkash
Advances in Materials Science and Engineering , 2011, DOI: 10.1155/2011/402376
Abstract: Solid solution of perovskite Pb,SrTiO3 in Pb-rich composition can be crystallized in borosilicate glassy matrix. The addition of rare earth and transition metal oxides is known to influence the crystallization behavior and surface morphology of perovskite crystallites in glassy matrix. In the present paper, the glasses in the lead-rich system 64[(PbxSr1-x)·TiO3]-25[2SiO2·B2O3]-5[K2O]-5[BaO] (1≤≤0.5) with the addition of 1 mol % La2O3 were prepared to study its effect on their crystallization behavior. Differential thermal analysis (DTA) patterns show one or more exothermic crystallization sharp peaks, which shift towards higher temperature with increasing concentration of SrO. The glasses were subjected to various heat-treatment schedules for crystallization. X-ray diffraction analysis of these glass ceramic samples shows that major crystalline phase of the entire glass ceramic sample with ≥0.5 was found to have tetragonal structure similar to PbTiO3 ceramic, and addition of La2O3 enhances the crystallization of the perovskite phase and retards the crystallization of minor phases.
Crystallization Behavior and Microstructural Analysis of Strontium Rich () Glass Ceramics in Presence of
C. R. Gautam,Devendra Kumar,Om Parkash
Advances in Materials Science and Engineering , 2011, DOI: 10.1155/2011/747346
Abstract: Crystallization and microstructural behavior of various strontium-rich glass ceramics in the system 65[(PbxSr1−x)TiO3]-24[2SiO2?B2O3]-5[BaO]-5[K2O]-1[La2O3] (0.0≤≤0.4) with addition of 1% La2O3 have been investigated. The addition of La2O3 has been found to play an important role in crystallization of perovskite (Pb,Sr)TiO3 as a solid solution phase. Also, it causes a change in the surface morphology of the fined crystallites of the major phase. Differential thermal analysis (DTA) shows only one exothermic crystallization peak, which shifts towards higher temperature with increasing amount of strontium oxide. Glasses were subjected to various heat treatment schedules for the crystallization. Very good crystallization of strontium-rich glass compositions is observed. X-ray diffraction studies confirm that cubic perovskite lead strontium titanate crystallizes as major phase. Lattice parameter decreases with increasing strontium content similar to lead strontium titanate ceramics. Uniform and interconnected crystallites are dispersed in glassy matrix.
Bambara nut: A review of utilisation, market potential and crop improvement
RJ Hillocks, C Bennett, OM Mponda
African Crop Science Journal , 2012,
Abstract: Bambara groundnut (Vigna subterranea (L.) Verdc.) originated in West Africa but has become widely distributed throughout the semi-arid zone of sub-Saharan Africa (SSA). Sharing a high nutritive value with other widely consumed legumes, bambara has an appealing flavour which is reflected in demand from small local and niche markets. Despite its high and balanced protein content, bambara remains under-utilised because it takes a long time to cook, contains anti-nutritional factors and does not dehull easily. Bambara yields well under conditions which are too arid for groundnut (Arachis hypogea), maize (Zea mays L.) and even sorghum (Sorghum bicolar). Its drought tolerance makes bambara a useful legume to include in climate change adaptation strategies. Existing bambara products are not well promoted in the local or international markets and new products are needed that highlight its inherent nutritional and culinary advantages. A number of projects on bambara, involving several countries in SSA since the 1980s, have failed to stimulate a sustainable increase in the production of the crop. The absence of functioning value chains has been a factor in this failure, as accessible market outlets might provide the required incentive for smallholder households to obtain improved seed and invest more of their land and labour in the crop. There is little documented evidence of trade in bambara but circumstantial evidence indicates considerable international demand. More attention should be given, therefore, to market research and development, with crop improvement programmes being more market-led, if bambara is to make a greater contribution to household income and rural development in SSA.
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