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Search Results: 1 - 10 of 542 matches for " Neyda Om Tapanes "
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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.
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

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.

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.
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.
Neutrino decay and the thermochemical equilibrium of the interstellar medium
Nestor Sanchez,Neyda Anez
Physics , 2000,
Abstract: We calculate the thermochemical equilibrium of the diffuse interstellar medium, including ionization by a photon flux F_{nu} from neutrino decay. The main heating mechanism considered is photoelectrons from grains and PAHs. For the studied range of F_{nu} values, there always exists two regions of stability (a warm and a cold phase) that can coexist in equilibrium if the thermal interstellar pressure is between a maximum value P_{max} and a minimum value P_{min}. High F_{nu} values (~10^4-10^5 cm^{-2} s^{-1}) can be consistent with observed interstellar pressures only if more efficient sources are heating the gas. It is shown that a neutrino flux increase (due, for example, to an increase in the supernova explosion rate) may stimulate the condensation of cold gas by decreasing P_{max} below the interstellar pressure value.
Tracking of Non-Rigid Object in Complex Wavelet Domain  [PDF]
Om Prakash, Ashish Khare
Journal of Signal and Information Processing (JSIP) , 2011, DOI: 10.4236/jsip.2011.22014
Abstract: In this paper we have proposed an object tracking method using Dual Tree Complex Wavelet Transform (DTCxWT). The proposed method is capable of tracking the moving object in video sequences. The object is assumed to be deform-able under limit i.e. it may change its shape from one frame to another. The basic idea in the proposed method is to decompose the image into two components: a two dimensional motion and a two dimensional shape change. The motion component is factored out while the shape is explicitly represented by storing a sequence of two dimensional models. Each model corresponds to each image frame. The proposed method performs well when the change in the shape in the consecutive frames is small however the 2-D motion in consecutive frames may be large. The proposed algorithm is capable of handling the partial as well as full occlusion of the object.
An Improved Image Denoising Method Based on Wavelet Thresholding  [PDF]
Hari Om, Mantosh Biswas
Journal of Signal and Information Processing (JSIP) , 2012, DOI: 10.4236/jsip.2012.31014
Abstract: VisuShrink, ModineighShrink and NeighShrink are efficient image denoising algorithms based on the discrete wavelet transform (DWT). These methods have disadvantage of using a suboptimal universal threshold and identical neighbouring window size in all wavelet subbands. In this paper, an improved method is proposed, that determines a threshold as well as neighbouring window size for every subband using its lengths. Our experimental results illustrate that the proposed approach is better than the existing ones, i.e., NeighShrink, ModineighShrink and VisuShrink in terms of peak signal-to-noise ratio (PSNR) i.e. visual quality of the image.
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