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Search Results: 1 - 10 of 365150 matches for " Hugo Alberto González Sánchez "
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CORRELACIóN ENTRE PROPIEDADES ANATóMICAS, RESISTENCIA A FLEXIóN ESTáTICA Y ENERGíA REQUERIDA PARA EL CORTE DE LA CA?A DE AZúCAR (Saccharum officinarum L.)
González Sánchez,Hugo Alberto; Toro Betancur,Alejandro; álvarez Mejía,Fernando; Cortés Marín,Elkin Alonso;
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: the microstructure, anatomical structure, bending resistance and the energy required to cut stems of three varieties of sugar cane cultivated in the valle del cauca ( colombia ), were studied in order to have useful data for the development of cutting blades. microestructural and anatomical characterization tasks were performed by optical microscopy ( om), and scanning electron microscopy (sem). the physical and mechanical properties were determined after adaptation of astm standards (which were developed for wood), while the consumption of energy during cutting was evaluated by using a modified charpy type impact pendulum. the fibers and silica particles showed different geometry and distribution in the stems of the three studied varieties, and a relation was established between the microstructure of the stems and the energy required to cut them in the modified charpy pendulum. generally speaking, cutting the internodes required higher specific energy than cutting the nodes, and the use of blades with cutting angle of 20° led to lower levels of energy consumption. also, a relation of proportionality between the effective cross-sectional area of fibers (atef) and the specific energy consumed in cutting, as well as between the flexibility coefficient and the modulus of elasticity in bending were found.
CORRELACIóN ENTRE PROPIEDADES ANATóMICAS, RESISTENCIA A FLEXIóN ESTáTICA Y ENERGíA REQUERIDA PARA EL CORTE DE LA CA A DE AZúCAR (Saccharum officinarum L.) CORRELATIONS AMONG ANATOMIC PROPERTIES, BENDING RESISTANCE AND ENERGY REQUIRED TO CUT SUGAR CANE (Saccharum officinarum L.)
Hugo Alberto González Sánchez,Alejandro Toro Betancur,Fernando álvarez Mejía,Elkin Alonso Cortés Marín
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: La microestructura, estructura anatómica, la resistencia a la flexión y la energía requerida durante el corte de los tallos de tres variedades de ca a de azúcar cultivadas en el Valle del Cauca (Colombia), fueron estudiados con el propósito de adquirir información útil para el desarrollo de cuchillas para corte de esta especie. Las labores de caracterización microestructural y anatómica se apoyaron en las técnicas de microscopía óptica y electrónica de barrido. Las propiedades mecánicas se determinaron adaptando algunas normas ASTM para maderas, mientras que la energía al corte se evaluó usando un péndulo de impacto tipo Charpy modificado. En los tallos de las tres variedades estudiadas se observaron diferentes distribuciones y dimensiones geométricas de las fibras y se verificó la presencia de partículas de sílice. Se presentó en general mayor requerimiento de energía específica al corte en los entrenudos que en los nudos y un menor consumo específico de energía al corte con las cuchillas con ángulo de afilado de 20°. Se establecieron relaciones entre la microestructura de los tallos, comportamiento a la flexión y al corte, destacándose la relación proporcional entre el área transversal efectiva de fibra (ATEF) y la energía específica al corte, así como entre el coeficiente de flexibilidad y el módulo de elasticidad en flexión. The microstructure, anatomical structure, bending resistance and the energy required to cut stems of three varieties of sugar cane cultivated in the Valle del Cauca ( Colombia ), were studied in order to have useful data for the development of cutting blades. Microestructural and anatomical characterization tasks were performed by optical microscopy ( OM), and scanning electron microscopy (SEM). The physical and mechanical properties were determined after adaptation of ASTM standards (which were developed for wood), while the consumption of energy during cutting was evaluated by using a modified Charpy type impact pendulum. The fibers and silica particles showed different geometry and distribution in the stems of the three studied varieties, and a relation was established between the microstructure of the stems and the energy required to cut them in the modified Charpy pendulum. Generally speaking, cutting the internodes required higher specific energy than cutting the nodes, and the use of blades with cutting angle of 20° led to lower levels of energy consumption. Also, a relation of proportionality between the effective cross-sectional area of fibers (ATEF) and the specific energy consumed in cutting, as well as between the fl
Variables físicas que explican la variabilidad de suelo aluvial y su comportamiento espacial
Jaramillo, Daniel Francisco Jaramillo;Gómez, María Luisa Anaya;Moná, Carlos Andrés Restrepo;Sánchez, Hugo Alberto González;Mejía, Fernando álvarez;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011001200017
Abstract: the objective of this work was to use the principal component and semivariance analyses to select physical variables that could explain the variability of an alluvial soil, in order to establish the spatial behavior of the chosen variables so that the location of experimental plots could be technically defined to study the abrasiveness effect on the wearing away of farm equipment. field tests were performed in 2008, on a 6,000 m2 flat lot with medium to heavy soil texture (vertic haplustepts). an intensive sampling was done in a grid of 10x14 m. the variables which had the most weight on the first three principal components were the contents of silt, fine and intermediate sand, intermediate gravel, soil moisture at field capacity, and the hygroscopic coefficient. except for the half sand and the field capacity, the other properties showed a high spatial dependence, and their distribution showed that in the experimental plot there are three sectors of differential accumulation of silt and fine sand. the combination of principal component analysis and geostatistics allowed for defining the soil properties involved in the wear of tools, their spatial pattern and the most appropriate way of distributing plots to study soil abrasiveness.
Estabilidad de rendimiento en genotipos mesoamericanos de frijol de grano en México
López Salinas, Ernesto;Acosta Gallegos, Jorge Alberto;Tosquy Valle, Oscar Hugo;Salinas Pérez, Rafael Atanasio;Sánchez García, Bertha María;Rosales Serna, Rigoberto;González Rivas, Carlos;Moreno Gallegos, Tomás;Villar Sánchez, Bernardo;Cortinas Escobar, Héctor Manuel;Zandate Hernández, Román;
Revista mexicana de ciencias agrícolas , 2011,
Abstract: in mexico, over 400 000 t of black beans are consumed every year, and the country's production is insufficient, which is why it is also imported. by planting varieties with a higher potential yield tan those used nowadays, greater amounts can be produced, and imports reduced or even avoided. the aim was to establish the yield and adaptability of lines and varieties of mesoamerican breed of black beans, in different environments in mexico (one in chiapas, three in veracruz, one in puebla, one in the state of mexico, two in guanajuato, one in tamaulipas, two in durango, one in zacatecas, one in nayarit and two in sinaloa) in 2008. the experiment was set up in a 4*4 lattice design with four repetitions, in fields of four five-meter long furrows, separated by 0.76 m. during the trials, diverse agricultural characteristics were determined, including yield. with the yield data, a combined analysis was performed (environments-genotypes) and the stability parameters were estimated using the main additives effect and multiplicative interaction model. highly significant differences were found (p< 0.01) between environments, genotypes and the interaction of both factors. the environments explained variance (59%) further, in comparison to the environment*genotype (23%) interaction and genotype (7%). the highest yields were obtained in mazatlán, sinaloa and durango, durango, whereas the lowest was found in guasave, sinaloa. the negro papaloapan variety displayed the highest average yield of 1.4 t ha-1 and presented a reduced interaction with the test environments.
Los libros de los espa oles en el Virreinato del Perú, siglos XVI y XVII
González Sánchez, Carlos Alberto
Revista de Indias , 1996,
Abstract: The analysis of judicial proceedings cencerning inheritances offers a means to evaluate the material success of emigrants to America in the sixteenth and seventeenth centuries, confronting their expectations with the real economic and social opportunities of the New World. The books accumulated by many Spaniards in Peru, besides being one aspect of this wealth, provide a means of studying such topics as trade and circulation of books in America, their prices, subject matters, and so forth. El análisis de los libros de Bienes de Difuntos contienen un material de gran valor para analizar el grado de éxito de los emigrantes a América en los siglos XVI y XVII, encontrando en ellos también respuesta a las oportunidades de ascenso económico y social, reales, en el Nuevo Mundo. Los libros, por otra parte, también ayudan al estudio de otros aspectos como el comercio y la circulación de libros en América, sus precios, materias, etc.
Consideraciones sobre el comercio de libros en Lima a principios del siglo XVII
González Sánchez, Carlos Alberto
Anuario de Estudios Americanos , 1997,
Abstract: Not available. El estudio de la circulación libraria en la América colonial continúa siendo un tema poco explotado, contrastando con el auge de las investigaciones sobre bibliotecas particulares o de instituciones de ense anza. Las razones, muy diversas, vienen determinadas por la escasez de fuentes, entre las que destacan los inventarios de mercaderes libreros, cuya información es indispensable para el conocimiento de las inquietudes lectoras y, en definitiva, de los esquemas mentales de la sociedad de la Edad Moderna. En esta ocasión, dos interesantes inventarios de mercancía libraria, negociada en Lima a principios del siglo XVII, nos ofrecerán algunos indicios de una faceta crucial de la vida humana: libros y lecturas.
PANDILLA 18 Y MARA SALVATRUCHA 13: VIOLENCIA Y DESCIUDADANIZACIóN
Hugo Moreno Hernández,Mónica Sánchez González
Cultura-Hombre-Sociedad , 2012, DOI: 10.7770/cuhso-v22n2-art212
Abstract: El presente trabajo es parte de una investigación sobre formas de reestratificación desde la sociedad civil. Aquí se observan las estrategias institucionales para el tratamiento del fenómeno de las pandillas transnacionales llevadas a cabo en El Salvador. Se observa cómo estas estrategias producen mayor violencia, sin presentar opciones organizativas orientadas a mejorar la vida de los jóvenes pandilleros, sin buscar crear formas sociales productivas en el sentido de asegurar a los jóvenes marginales instancias de resistencia a los influjos del sistema capitalista que los excluye. En estos términos, se propone observar las estrategias gubernamentales y sus efectos en la transformación de las pandillas hacia formas más violentas y jerarquizadas, debido a la acción criminalizante de las instituciones del gobierno. Así pues, se propone la observación de la reestratificación institucional de las pandillas, mediante la criminalización y su asimilación al crimen organizado, como elemento que ha producido una tendencia a la jerarquización, la clandestinidad y el aumento de la violencia.
Cell-Phone Recycling by Solvolysis for Recovery of Metals  [PDF]
Lorena Eugenia Sánchez Cadena, Zeferino Gami?o Arroyo, Mario Alberto González Lara, Q. Demetrio Quiroz
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.31008
Abstract:

Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are an important resource for the recovery of metals in terms of mass and volume. In this research a chemical recycling of mobile phones by solvolysis was investigated. The processing was performed by comminution in a hammer mill followed by screening to obtain mesh-4 sized flakes. Flakes were subjected to solvolysis. Different reaction conditions were tested. A reaction time between 2 - 7 hours and a temperature between 150°C - 300°C were the optimum conditions to dissolve the polymer contained in mobile phones. Metals were separated by filtration. Chemical analyses (ATR FT-IR, UV) were carried out on the solvent and the mobile phone flakes before and after solvolysis. A SEM study was carried out, before and after solvolysis, but only to the mobile phone flakes. Thermal transitions of mobile phone flakes were determined by DSC. Chemical results showed that some aromatic species migrate from mobile phones flakes to the solvent, due to the solvolysis reaction. Thermal analysis showed that the Tg, (glass transition temperature) of mobile phone flakes after solvolysis was different to Tg of the polymer before solvolysis, this is due to chemical changes in the molecule. A comparative SEM study revealed that, after solvolysis, the polymer contained in mobile phone flakes is more elastomeric. After solvolysis, solvent was recovered by means of a rotatory evaporator, so that it can be used again. The results obtained in this research showed that solvolysis is an alternative for metal recovery from mobile phones.

Liver Lead Levels in Snow Goose (Chen caerulescens) in a Wetland near the City of Durango, Mexico  [PDF]
Martín Emilio Pereda-Solís, Alicia Zulema Cárdenas González, José Hugo Martínez Guerrero, Luis Francisco Sánchez Anguiano, Federico Rosales Alférez
Open Journal of Animal Sciences (OJAS) , 2015, DOI: 10.4236/ojas.2015.51004
Abstract: The use of lead in ammunition for hunting exposes waterfowl to lead poisoning (plumbism) by accidental consumption of shotgun pellets. To test this hypothesis we sampled 18 liver tissue samples of Snow Goose (Chen caerulescens) collected during the 2012-2013 hunting season in a wetland near the city of Durango, Mexico. We quantified liver lead levels using an atomic absorption spectrophotometer and portions of liver were fixed and stained for their histological study. Average lead concentration (in dry weight) were under the normal range (mean = 0.73 ± 0.2, standard error) which do not represent any risk of poisoning. Liver tissue injuries were not observed in the histopathological analysis, suggesting no reaction to a xenobiotic agent such as lead. Gastrointestinal content analysis showed lead pellet in the gizzard of one individual, but we could not find a relationship between pellet ingestion and lead concentration in the liver. Although the results did not provide evidences of lethal or sublethal effects caused by lead poisoning, they show a possible risk due to the presence of lead pellets in the digestive tract.
Gaudiebility and Psychopathological Symptoms in the Mexican Population  [PDF]
Joel Omar González-Cantero, Víctor Hugo González-Becerra, Laura Miriam Ramírez-Zamora, José Guadalupe Salazar-Estrada, Jahaziel Molina del Rio, Diana Ortiz Sánchez, Anaid Amira Villegas Ramírez
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.95057
Abstract: It is necessary to identify variables of Positive Psychology related to mental health and well-being. Therefore, the aim of this study was to identify the relationship between gaudiebility and psychopathological symptoms in the Mexican population. The participants were 285 Mexicans between 14 and 78 years old. Gaudiebility was measured with the Gaudiebility Scale of Padrós & Fernández-Castro and psychopathological symptoms with the Symptom Checklist-90 (SCL-90). Results show a statistically significant and negative correlation (-.324, p < .001) in which the higher the gaudiebility, the lower the level of Global Severity Index. Although more research is needed, results suggest that the development of gaudiebility could be a protective factor for mental health.
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