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Search Results: 1 - 10 of 369909 matches for " Carlos E MEJIA G "
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PRODUCCIóN DE ETANOL A PARTIR DE ALMIDóN DE YUCA UTILIZANDO LA ESTRATEGIA DE PROCESO SACARIFICACIóN- FERMENTACIóN SIMULTáNEAS (SSF)
CASTA?O P,Hader I; MEJIA G,Carlos E;
Vitae , 2008,
Abstract: the world trend on fuel management, in special biofuels like ethanol, have gone to explorer new methodologies of process to optimize its production by this reason in this research is about simultaneous sacarification fermentation process and evaluate initial concentration of reducing sugar, and enzyme dosing of spirizyme fuel? are evaluated on productivity and final concentration of ethanol, under ssf (simultaneous saccharification and fermentation) process, from the product of the licuefaction process of cassava starch as substrate. the ssf process is evaluated against shf (independent saccharification and fermentation) process as control. only the factor, initial concentration of substrate presents effect over ethanol productivity. the kinetic of ssf process, in opposite to the shf process, presents time diminution of the global process around 47 y 33% to substrate levels of 150 and 200 g/l respectively. the productivity values are most at a 33% to 150 g/l of reducing sugar, and they keep constant to 200 g/l reducing sugar. the glucose in ssf strategy, at the time it is producing, it is transformed to ethanol, does not allowing to reach superior concentration to 100 g/l of reducing sugar, this implicates there is not substrate inhibition. the ethanol concentration doesn't affect the enzymatic process of sacharification. the ssf process demonstrates his technical viability on the ethanol production, to reduce time an energy requirements on the ethanol production from cassava flour.
PRODUCCIóN DE ETANOL A PARTIR DE ALMIDóN DE YUCA UTILIZANDO LA ESTRATEGIA DE PROCESO SACARIFICACIóN- FERMENTACIóN SIMULTáNEAS (SSF) ETHANOL PRODUCTION FROM CASSAVA STARCH USING THE PROCESS STRATEGY SIMULTANEOUS SACCHARIFICATION-FERMENTATION
Hader I CASTA?O P,Carlos E MEJIA G
Vitae , 2008,
Abstract: La tendencia mundial en el manejo de los combustibles, en especial los biocombustibles como el etanol, ha llevado a explorar nuevas metodologías de proceso para optimizar su producción; por tal razón se aborda en esta investigación el proceso sacarificación fermentación simultáneas, se evalúa la influencia de la concentración de azúcares reductores y la dosificación de la enzima Spirizyme fuel sobre la productividad y concentración final de etanol, bajo el proceso SSF (sacarificación -fermentación simultáneas), partiendo del licuado de almidón de yuca como sustrato. El proceso SSF se compara con un control con características de sacarificación-fermentación independientes (SHF), proceso convencional. Sólo el factor concentración inicial de sustrato presenta efecto sobre la productividad de etanol. Las cinéticas de proceso, frente a las del control, presentan reducciones de tiempo de 47 y 33% para los niveles de sustrato evaluados. Los niveles de productividad son mayores en un 33% para el nivel de 150 g/l de AR (azúcares reductores) y se mantiene constante para 200 g/l. La glucosa en la estrategia SSF, conforme se produce se transforma en etanol, no permitiendo alcanzar concentraciones superiores a 100 g/l, lo que se traduce en que no se presentan inhibiciones por sustrato. La concentración de etanol no afecta la reacción de la enzima en el proceso de sacarificación. El proceso SSF demuestra su viabilidad técnica en la producción de alcohol, al reducir los tiempos y necesidades de energía en la producción de alcohol carburante a partir de almidón de yuca The world trend on fuel management, in special biofuels like ethanol, have gone to explorer new methodologies of process to optimize its production by this reason in this research is about simultaneous sacarification fermentation process and evaluate initial concentration of reducing sugar, and enzyme dosing of Spirizyme fuel are evaluated on productivity and final concentration of ethanol, under SSF (Simultaneous Saccharification and Fermentation) process, from the product of the licuefaction process of cassava starch as substrate. The SSF process is evaluated against SHF (Independent Saccharification and Fermentation) process as control. Only the factor, initial concentration of substrate presents effect over ethanol productivity. The kinetic of SSF process, in opposite to the SHF process, presents time diminution of the global process around 47 y 33% to substrate levels of 150 and 200 g/l respectively. The productivity values are most at a 33% to 150 g/l of reducing sugar, and they keep constant to
Puntaje de riesgo para morbilidad y mortalidad en pacientes sometidos a intervencionismo coronario percutáneo
Fernández,Andrés; Tenorio,Carlos A; Eusse,Carlos A; Rodríguez,Arturo; Uribe,Carlos E; Villa,Juan P; Restrepo,Ricardo; Mejia,Marcela; Vega,Juliana; Gómez,Juan F; Franco,Gloria;
Revista Colombiana de Cardiología , 2008,
Abstract: the main objective of this observational study was to establish a mortality risk score for intra-hospital morbidity and mortality in patients submitted to percutaneous coronary intervention (pci) after having suffered one of the following acute coronary syndromes: unstable angina (ua), acute myocardial infarction without st elevation (nstemi) or acute myocardial infarct with st elevation (stemi). clinical and demographic data of 1,300 patients treated in the clinic between 2003 and 2006 were recollected in a retrospective way with the aim of obtaining a valid risk score for the colombian population. this was realized through a data base of multiple pre-procedure variables (personal antecedents), intra-procedure variables (time elapsed since the arrival to er to the moment of catheterization and number of diseased vessels among others) and post-procedure variables (morbimortality complications). data analysis was then performed through a logistic regression model in order to determine which risk factors were statistically significant in causing some of the results evaluated. the principal results evaluated were death, adverse hematological events and hospital stay; after the analysis we found that the main factors related to patients? morbimortality, were the type of patient (or the type of coronary syndrome suffered), age and homodynamic state at admission (presence of cardiogenic shock). from these results a risk score through pre-procedure, post-procedure and intra-hospital variables was developed.
Decision Making in Sustainable Development: Some Methods to Evaluate Energy and Nonrenewable Resources Waste When Using Some Plastics  [PDF]
Lol-chen Alegria Mejia, Carlos E. Escobar Toledo, Barbara M. Ramírez Rayle
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.23048
Abstract: This paper explores a decision making model for a multidisciplinary problem in nature. This problem considers the role of energy use in sustainable development and the potential sources to increase energy efficiency during its whole life cycle; it also deals with multicriteria decision making of plastic materials used in a day to day basis. Exergy analysis of plastic materials used to the manufacture of disposable polyethylene bags comparing them with other materials that can be used for substitution will be important to take decisions. We are also interested in plastic poly (ethylene Terephthalate or PET) bottles. The calculation of the incoming and outgoing Exergy flows during the production processes are carried out. The Exergy loss considering the sustainability concept, Green House Gases emissions, real energy flows needed to the chain of processes, material balances in the productions chains and value added, are presented as a set of criteria to make decisions of alternative materials including the actual ones. A case study for Mexico’s market will be developed in order to prove the methodology. It offers some interesting data about consumption and production of bags and bottles.
Caracterización del aceite de la almendra de Astrocaryum macrocalyx (Burret)
Lognay, G.,Desmedt, A.,Mejia, K.,Trevejo, E.
Grasas y Aceites , 1995,
Abstract: In the present work we investigated the glyceride and sterol compositions of Astrocaryum macrocalyx ("huicungo") kernel fat. This species is native from the Peruvian Amazonia (Iquitos). Gas chromatographic analysis of the fatty acids revealed 8 components, among which lauric (54.5%) and myristic (21.9%) acids predominate. The sterol profile is classic; β-sitosterol and campesterol are the main constituents (74.3 and 12.0% respectively) while the Δ7-sterols were detected in minute amounts. X-ray diffraction measurements showed that Astrocaryum macrocalyx kernel fat is stabilized in the β1'-2 polymorphic form at ambiant temperature. En este trabajo se analizan los glicéridos y esteroles del aceite de la almendra de Astrocaryum macrocalyx ("huicungo"), una especie nativa de la Amazonia peruana (Iquitos). El análisis por cromatografía gaseosa de los ácidos grasos muestra la presencia de 8 componentes, entre los cuales predominan los ácidos grasos láurico (54.5%) y mirístico (21.9%). La composición esterólica es clásica; el β-sitosterol y el campesterol son mayoritarios (74.3 y 12.0% respectivamente del total). Los Δ7-esteroles están presentes en forma de trazas. Las medidas realizadas por espectrometría de difracción de rayos-X han demostrado que el "huicungo" se estabiliza en la forma polimórfica β1'-2 a temperatura ambiente.
Introduccion y evaluacion de Phymastichus coffea (tlymenoptera: Eulophidae) en fincas de peque?os caficultores, a traves de investigaciòn participativa
ARISTIZABAL A,LUIS FERNANDO; SALAZAR E,HUGO MAURICIO; MEJIA M,CARLOS GONZALO; BUSTILLO P.,ALEX E;
Revista Colombiana de Entomología , 2004,
Abstract: in collaboratiòn with ico-cfc-cabi bioscience, cenicafe conducted a farmer participatory research project with smallholder coffee growers in caldas, quindio and risaralda, related to the management of the coffee berry borer. during this study the first release of phymastichus coffea (la salle) was made in colombia with the main purpose of allowing farmers to learn about this parasitoid, initiate its introduction, and evaluate its establishment. forty-one coffee farms participated in the study, which were located between 1.200 and 1.800 meters elevatiòn. for 20 months coffee berry borer management was based on frequent harvests of mature coffee and releases of p. coffea. farmers made evaluatiòns of insect infestaciòn, positions of borer penetratiòn in the berry and collected infested berries to evaluate the parasitoid establishment. altogether 455 samples of infested berries were collected. in 49,2% (n = 224) of the samples the presence of p. coffea was observed. the presence of p. coffea was detected up to 14 months after the last release. in farms of balboa, montenegro and belalcazar, the highest parasitism was observed: mean of 5,6. 5,6 and 4,7%, respectively. in contrast, farms of riosucio, buenavista and santa rosa de cabal, had lower parasitism: mean of 0,7. 1,3 and 1,9%. respectively. maximum parasitism observed was 42%. it is important to emphasize that p. coffea was present in 87,5 % of the farms where it was released, demonstrating that it can be established in the coffee agroecosystems of the country.
Introduccion y evaluacion de Phymastichus coffea (tlymenoptera: Eulophidae) en fincas de peque os caficultores, a traves de investigaciòn participativa Introduction and evaluatiòn of Phymastichus coffea (tlymenoptera: Eulophidae) in smallholder coffee farms, through participatory research
LUIS FERNANDO ARISTIZABAL A,HUGO MAURICIO SALAZAR E,CARLOS GONZALO MEJIA M,ALEX E BUSTILLO P.
Revista Colombiana de Entomología , 2004,
Abstract: Cenicafe en convenio con el ICO-CFC-CABI Bioscience adelanto un proyecto de investigacion participativa con peque os caficultores de Caldas, Quindio y Risaralda relacionado con el manejo de la broca del cafe. Durante este proyecto se realizaron las primeras liberaciones de Phymastichus coffea (La Salle) en Colombia, con el proposito de darlo a conocer a los caficultores. iniciar su introduccion y evaluar su establecimiento. En el estudio se consideraron 41 fincas localizadas entre 1.200 y 1.800 m de altitud. Durante 20 meses el manejo de la broca se baso en recolecciones frecuentes de cafe maduro y en liberaciones de P. coffea. Los caficultores realizaron evaluaciones de infestacion de broca, posiciones de penetracion en los frutos y colectaron frutos infestados para evaluar el establecimiento del parasitoide. En total se colectaron 455 muestras de frutos infestados. En el 49,2% (N = 224) de las muestras se observò la presencia de P. coffea. Se detectò la presencia de P. coffea hasta 14 meses despues de la ultima liberacion. En las fincas de los municipios de Balboa, Montenegro y Belalcazar se observaron los parasitismos mayores 5,6, 5,6 y 4.7% en promedio, respectivamente. En contraste, las fincas de los municipios de Riosucio. Buenavista y Santa Rosa de Cabal presentaron parasitismos menores 0,7, 1,3 y 1,9% en promedio. respectivamente. El parasitismo maximo fue 42%. Es importante resaltar la presencia de P. coffea en el 87,5% de los predios en donde fue liberado, ya que se demuestra que se puede establecer en los agroecosistemas cafeteros del pais. In collaboratiòn with ICO-CFC-CABI Bioscience, Cenicafe conducted a farmer participatory research project with smallholder coffee growers in Caldas, Quindio and Risaralda, related to the management of the coffee berry borer. During this study the first release of Phymastichus coffea (La Salle) was made in Colombia with the main purpose of allowing farmers to learn about this parasitoid, initiate its introduction, and evaluate its establishment. Forty-one coffee farms participated in the study, which were located between 1.200 and 1.800 meters elevatiòn. For 20 months coffee berry borer management was based on frequent harvests of mature coffee and releases of P. coffea. Farmers made evaluatiòns of insect infestaciòn, positions of borer penetratiòn in the berry and collected infested berries to evaluate the parasitoid establishment. Altogether 455 samples of infested berries were collected. In 49,2% (N = 224) of the samples the presence of P. coffea was observed. The presence of P. coffea was detected up to
Entanglement Across a Transition to Quantum Chaos
Carlos Mejia-Monasterio,Giuliano Benenti,Gabriel G. Carlo,Giulio Casati
Physics , 2004, DOI: 10.1103/PhysRevA.71.062324
Abstract: We study the relation between entanglement and quantum chaos in one- and two-dimensional spin-1/2 lattice models, which exhibit mixing of the noninteracting eigenfunctions and transition from integrability to quantum chaos. Contrary to what occurs in a quantum phase transition, the onset of quantum chaos is not a property of the ground state but take place for any typical many-spin quantum state. We study bipartite and pairwise entanglement measures, namely the reduced Von Neumann entropy and the concurrence, and discuss quantum entanglement sharing. Our results suggest that the behavior of the entanglement is related to the mixing of the eigenfunctions rather than to the transition to chaos.
Simulating noisy quantum protocols with quantum trajectories
Gabriel G. Carlo,Giuliano Benenti,Giulio Casati,Carlos Mejia-Monasterio
Physics , 2004, DOI: 10.1103/PhysRevA.69.062317
Abstract: The theory of quantum trajectories is applied to simulate the effects of quantum noise sources induced by the environment on quantum information protocols. We study two models that generalize single qubit noise channels like amplitude damping and phase flip to the many-qubit situation. We calculate the fidelity of quantum information transmission through a chaotic channel using the teleportation scheme with different environments. In this example, we analyze the role played by the kind of collective noise suffered by the quantum processor during its operation. We also investigate the stability of a quantum algorithm simulating the quantum dynamics of a paradigmatic model of chaos, the baker's map. Our results demonstrate that, using the quantum trajectories approach, we are able to simulate quantum protocols in the presence of noise and with large system sizes of more than 20 qubits.
Improvement and analysis of a pseudo random bit generator by means of cellular automata
J. S. Murguia,M. Mejia-Carlos,H. C. Rosu,G. Flores-Era?a
Physics , 2010, DOI: 10.1142/S0129183110015440
Abstract: In this paper, we implement a revised pseudo random bit generator based on a rule-90 cellular automaton. For this purpose, we introduce a sequence matrix H_N with the aim of calculating the pseudo random sequences of N bits employing the algorithm related to the automaton backward evolution. In addition, a multifractal structure of the matrix H_N is revealed and quantified according to the multifractal formalism. The latter analysis could help to disentangle what kind of automaton rule is used in the randomization process and therefore it could be useful in cryptanalysis. Moreover, the conditions are found under which this pseudo random generator passes all the statistical tests provided by the National Institute of Standards and Technology (NIST)
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