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Search Results: 1 - 10 of 31741 matches for " González Giovanni "
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Influence of pH to Increase Grafting Degree into Fluoropolymers  [PDF]
Giovanni González-Pérez, Ademar Benevolo Lugao
Open Journal of Polymer Chemistry (OJPChem) , 2017, DOI: 10.4236/ojpchem.2017.73004
Poly(ethylene-alt-tetra-fluoroethylene (ETFE) and poly(tetrafluoroethylene-cohexafluoropropylene) (FEP) were pre-irradiated under air using a Co60 gamma source to graft styrene at low pH. Grafting copolymers were tuned by study of different parameters (monomer, reaction time, temperature, and pH with addition of sulfuric acid (H2SO4)). The maximum degree of grafting was 80% and 40% for ETFE and FEP respectively at dose 2 kGy. Influence of low pH in grafting degree by adding sulfuric acid was studied. Grafting degree was examined by infrared (FTIR-ATR), differential scanning calorimetry (DSC) and swelling behavior analysis after sulfonation process.
Visiones del pasado, el presente y el futuro de la Lingüística: A propósito de los 40 a os de Revista Signos. Estudios de Lingüística
Giovanni Parodi,Cristian González
Revista Signos , 2007,
DYNA , 2007,
Abstract: in this paper, the results of an analytical, computational and experimental investigation are presented, where are developed inelastic methods for modeling (in plane and out plane) concrete frames infilled with nonreinforced masonry. in the paper the complex interaction of this system is exposed and a methodology that allows to considering these elements in the conventional analysis and designs is proposed. the presented methodologies include modeling of frames in contact with the masonry walls and modeling of frames which are isolated from these elements. additionally, the comparison of the experimental and computational results is made, which allows to calibrating the analytical models with the conventional construction techniques and the particular characteristics of the materials that are currently used.
DYNA , 2007,
Abstract: the nonstructural walls can be displaced from a place to another one by variations in the use of the spaces, originating even during moderate earthquakes, a frame-infill interaction that can significantly alter the conception of the conventional designs. therefore, it is necessary to evaluate the infills influence related to the local and global inelastic behavior of the buildings, especially when this interaction causes negative effects to the elements that conform the system. considering the previous fact, in this paper the results of an analytical and computational investigation are presented, where the inelastic modeling of three typical buildings (of 3, 7 and 13 floors) is made, using the equivalent diagonal strut method, in order to quantify the influence (positive or negative) of the masonry infills in the local and global behavior of the constructions. additionally, it is presented a tool that allows considering these elements during the structural analyses and design process.
Modelación inelástica de pórticos de concreto con mampostería no reforzada
DYNA , 2007,
Abstract: En este trabajo se presentan los resultados de una investigación analítica, computacional y experimental, donde se desarrollan métodos inelásticos de modelación (dentro y fuera del plano) de pórticos de concreto rellenos con mampostería no reforzada. Se expone la compleja interacción de este sistema y se propone una metodología que permite tener en cuenta estos elementos en los análisis y dise os convencionales. Las metodologías presentadas incluyen la modelación de pórticos en contacto con los muros de mampostería y los pórticos que se encuentran aislados de estos elementos. Adicionalmente, se realiza la comparación de los resultados experimentales y computacionales con el objeto de calibrar los modelos analíticos teniendo en cuenta las técnicas de construcción convencionales y las características particulares de los materiales utilizados actualmente.
Influencia de la mampostería no reforzada en el comportamiento inelástico de pórticos de concreto
DYNA , 2007,
Abstract: Los muros no estructurales pueden ser desplazados de un lugar a otro por variaciones en el uso de los espacios, originando aún durante sismos moderados, una interacción pórtico-relleno que puede alterar significativamente la concepción de los dise os convencionales. Por lo tanto, es necesario evaluar la influencia que tienen estos rellenos en el comportamiento inelástico local y global de los edificios, especialmente cuando esta interacción causa efectos negativos a los elementos que conforman el sistema. Teniendo en cuenta lo anterior, se presentan en este trabajo los resultados de una investigación analítica y computacional, donde se realiza la modelación inelástica de tres edificios típicos (de 3, 7 y 13 pisos) utilizando el método del puntal diagonal equivalente, con el propósito de cuantificar la influencia (positiva ó negativa) de los rellenos de mampostería en el comportamiento local y global de las edificaciones. Adicionalmente se presenta una herramienta que permite tener en cuenta estos elementos durante el proceso de análisis y dise o estructural.
Temporal Variation in Composition and Abundance of Phytoplankton Species during 2011 and 2012 in Acapulco Bay, Mexico  [PDF]
Giovanni Moreno-Díaz, Agustín A. Rojas-Herrera, Juan Violante-González, Justiniano González-González, José Luis Rosas Acevedo, Sergio García Ibá?ez
Open Journal of Marine Science (OJMS) , 2015, DOI: 10.4236/ojms.2015.53029
Abstract: Phytoplankton samples were collected in Acapulco Bay during 2011 (January-April and September) and 2012 (April-July, October, and November) with the objective of determining the abundance and species composition. Samples were collected in two stations located in the bay. A total of 82 species were identified: 42 dinoflagellates, 35 diatoms, three cyanobacteria, and two silicoflagellates. Dinoflagellates were more abundant in the dry season, while diatoms dominated during rainy season. At least seven dinoflagellate species were recorded as potentially toxic, which may increase their populations and turn into harmful algal blooms (HABs) if environmental conditions within the bay are modified. In April 2012 a HAB of the non-toxic species Neoceratium balechii was documented.
Estudios Gerenciales , 2011,
Abstract: this article discusses the implementation of active employment generating policies for the labor market in cali, colombia. the main objectives of active employment generating policies are: reducing the unemployment rate, decreasing participation in the informal labor market, and replacing poor quality jobs with good quality ones. the collective actions of regional public agencies, regional entrepreneurs, and academic institutions are fundamental to generating high quality employment in the city.
DYNA , 2007,
Abstract: the results of an analytical and computational investigation are described in this article, where the variation of the framed buildings drift determined, considering the nucleus compressive strength of concrete obtained in the laboratory f'c(l), and the real resistance f'c(r) which is calculated based on the diameter of concrete nuclei extraction. once the percentages of the drift variations with the corrected and not corrected resistance are determined, the percentages of variation variables as the resistance and the diameter of extraction are related to establish the type of existing behavior. finally, equations are obtained to relate the parameters in study, which allow the structural engineer to determine the percentage in that the drift of a construction is diminished, if this one is modeled with the real resistance of concrete compression f'c(r) and not with the concrete compression obtained of the nucleus f'c(l).
Experimental assessment of damping factors in concrete housing walls Evaluación experimental de los factores de amortiguamiento en muros de concreto para vivienda
Carrillo Julián,Alcocer Sergio M.,González Giovanni
Ingeniería e Investigación , 2012,
Abstract: Thin walls having low concrete strength, minimum web steel ratios and web shear reinforcement made of welded wire meshes are commonly used in low-rise concrete housing. The damping factor commonly used for code-based dynamic analysis was evaluated based on seismic response measured during shake table tests of six low-rise concrete walls. The variables studied were the type of concrete (normal and lightweight), the web steel shear ratio (0.125% and 0.25%), the type of web shear reinforcement (deformed bars and welded wire meshes) and the effect of openings (doors and windows). Dynamic properties were evaluated considering the advantages of frequency-domain system identification, using the dynamic transfer function amplitude fitting method. The effect of failure mode on damping factor is discussed. An equation for estimating damping associated with a particular vibration period value is also proposed. It was observed that a 5% damping factor (assumed for dynamic analysis of concrete housing in the range of lineal elastic behaviour) was consistent with the values measured here. En viviendas de concreto de baja altura se emplean usualmente muros delgados con baja resistencia del concreto, cuantías mínimas de refuerzo y mallas de alambre soldado para refuerzo a cortante en el alma. Con base en la respuesta sísmica medida durante el ensayo en mesa vibratoria de seis muros de concreto de baja altura se evalúa el factor de amortiguamiento que se utiliza usualmente en el análisis dinámico especificado en los reglamentos. Las variables estudiadas fueron el tipo de concreto (peso normal y ligero), la cuantía —0,125% y 0,25%— y el tipo de refuerzo a cortante en el alma —barras corrugadas y malla de alambre soldado— y el efecto de aberturas (puerta y ventana). Tomando en cuenta las ventajas de los sistemas de identificación en el dominio de la frecuencia, las propiedades dinámicas se evaluaron utilizando el método de ajuste de amplitud de la función de transferencia dinámica. En el artículo se discute el efecto del modo de falla sobre el factor de amortiguamiento y se propone una ecuación para estimar el amortiguamiento asociado a un determinado valor del periodo de vibración. Se observó que el factor de amortiguamiento del 5%, supuesto en el análisis dinámico de viviendas de concreto en el intervalo de comportamiento elástico lineal, es consistente con los valores medidos.
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