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Search Results: 1 - 10 of 144450 matches for " F Paraguay "
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Synthesis and Characterization of Bimetallic Gold-Silver Core-Shell Nanoparticles: A Green Approach  [PDF]
A. Calagua, H. Alarcon, F. Paraguay, Juan Rodriguez
Advances in Nanoparticles (ANP) , 2015, DOI: 10.4236/anp.2015.44013
Abstract: Bimetallic gold-silver core-shell nanoparticles were prepared by chemical reduction in aqueous solution, following a method that was friendly to the environment, allowing us to use this for medicinal purposes. Gold nanoparticles were synthesized, and silver cations were then reduced on the nanoparticles. Using the optical properties of metallic nanoparticles, surface plasmon resonance was determined by UV-Vis spectroscopy, and the values obtained for gold and silver were approximately 520 nm and 400 nm in wavelength, respectively. The absorption peaks of the surface plasmon band show a clear red-shift due to size effect in the case of the silver surface, and a plasmon coupling effect, in the case of gold. To obtain a better understanding of the coating conditions, high resolution transmission electron microscopy was used. The average hydrodynamic size and the size distribution of the synthesized nanoparticles were obtained by dynamic light scattering. The development of this process, which is benign for the environment, opens the possibility for many applications in the areas of renewable energy, medicine and biology.
ESTUDIO MEDIANTE MICROSCOPIA ELECTRONICA DE TRANSMISION DE PRECIPITADOS DE CARBURO DE NIOBIO EN UN ACERO MICROALEADO
Béjar,L; Hernández,C. A; Mancilla,J. E; Paraguay,F; Espinosa,F;
Revista Latinoamericana de Metalurgia y Materiales , 2002,
Abstract: in this paper a study by transmission electronic microscopy (stem) and eds of the nbc deformation induced precipitates of a microalloyed steel is presented. the steel was hot rolled in a laboratory scale two-high reversing mill. it is reported the form, size, number of particles per area unit, and precipitates distribution into the microstructure. eds analysis and the electron energy loss (peels) study in the steel matrix and precipitates is presented.
ESTUDIO MEDIANTE MICROSCOPIA ELECTRONICA DE TRANSMISION DE PRECIPITADOS DE CARBURO DE NIOBIO EN UN ACERO MICROALEADO
L Béjar,C. A Hernández,J. E Mancilla,F Paraguay
Revista Latinoamericana de Metalurgia y Materiales , 2002,
Abstract: En este trabajo se presentan los resultados del estudio por microscopia electrónica de transmisión (MET) y EDX de los precipitados inducidos por deformación de NbC en un acero microaleado al niobio, deformado en caliente en un laminador dúo reversible escala laboratorio. Se dan los resultados del estudio mediante MET de las diferencias de forma, tama o, número de partículas por unidad de área y distribución de los precipitados a lo largo de la microestructura. Se muestran los análisis de EDX y el estudio por pérdida de energía de electrones (PEELS) realizados en la matriz del acero y de los precipitados. In this paper a study by transmission electronic microscopy (STEM) and EDS of the NbC deformation induced precipitates of a microalloyed steel is presented. The steel was hot rolled in a laboratory scale two-high reversing mill. It is reported the form, size, number of particles per area unit, and precipitates distribution into the microstructure. EDS analysis and the electron energy loss (PEELS) study in the steel matrix and precipitates is presented.
International Seminar of Public Health Policy
Asuncion, Paraguay International Seminar of Public Health
Social Medicine , 2008,
Abstract:
Síntesis y caracterización de nanoestructuras de óxidos de CoMoW parcialmente sulfuradas y su aplicación en la HDS de DBT
Huirache-Acu?a, R.;Sánchez-Bautista, M.G.;Lemus-Ruiz, J.;Ornelas, C.;Paraguay-Delgado, F.;Rivera-Mu?oz, E.M.;
Revista mexicana de ingeniería química , 2010,
Abstract: in this paper, the synthesis and characterization of comow nanostructured oxides, partially sulfided, as well as its application as catalysts in the reaction of hydrodesulfurization (hds) of dibenzothiophene (dbt) is presented. all nanostructures were obtained by a two-step hydrothermal/gas phase reduction. firstly, comow oxides precursors were prepared using a hydrothermal method. subsequently, all precursors were reduced and activated under h2s/h2 at 500°c. nanostructures were characterized by transmission electron microscopy (tem), x-ray powder diffraction (xrd) and the specific surface areas of the materials were measured using the bet method. the catalytic activity and selectivity measurements in the hds of dbt reaction were also presented.
Rela??o entre satisfa??o com aspectos psicossociais e saúde dos trabalhadores
Martinez,Maria Carmen; Paraguay,Ana Isabel Bruzzi Bezerra; Latorre,Maria do Rosário Dias de Oliveira;
Revista de Saúde Pública , 2004, DOI: 10.1590/S0034-89102004000100008
Abstract: objective: to identify whether psychosocial satisfaction at work is associated with workers' health and to verify if sociodemographic characteristics have an impact on these associations. methods: a cross-sectional study was carried out in 224 employees of a private managed care and retirement savings company in s?o paulo, brazil. four self-administered questionnaires on sociodemographic features, job satisfaction, and health (physical, mental, and work ability) were applied. variables associations were analyzed using t-student, mann-whitney and kruskal-wallis tests, spearman correlation coefficient, and multiple linear regression analysis. results: job satisfaction was associated with duration in the company (p <0.001) and job position (p=0.003), where greater satisfaction was observed among workers with shorter duration in the company and those in managing positions. job satisfaction was associated with mental health and work ability (vitality: p<0.001; social aspects: p=0.055; emotional aspect: p=0.074; mental health: p<0.001; and work capacity: p=0.001). conclusions: job satisfaction is associated with workers' health regarding their "mental health" and "work ability", showing the importance of psychosocial factors for their health and well-being. changes are suggested in work conception and organization to focus psychosocial factors. longitudinal studies are recommended to investigate the causal direction of these associations.
Rela o entre satisfa o com aspectos psicossociais e saúde dos trabalhadores
Martinez Maria Carmen,Paraguay Ana Isabel Bruzzi Bezerra,Latorre Maria do Rosário Dias de Oliveira
Revista de Saúde Pública , 2004,
Abstract: OBJETIVO: Identificar se satisfa o com aspectos psicossociais no trabalho está associada à saúde dos trabalhadores e verificar se essas associa es s o influenciadas por características sociodemográficas. MéTODOS: Estudo transversal realizado com 224 empregados de uma empresa de auto-gest o de planos de previdência privada e de saúde na cidade de S o Paulo. Foram administrados quatro questionários auto-aplicados referentes a aspectos sociodemográficos, satisfa o no trabalho e saúde (física, mental e capacidade para o trabalho. As associa es entre variáveis foram analisadas por meio dos testes t-Student, Mann-Whitney, Kruskal-Wallis, coeficiente de correla o de Spearman e da análise de regress o linear múltipla. RESULTADOS: Satisfa o no trabalho apareceu associada ao tempo na empresa (p<0,001) e cargo (p=0,003), onde maiores níveis de satisfa o foram observados entre os trabalhadores com menor tempo na empresa e aqueles com cargos de dire o. A satisfa o no trabalho esteve associada às dimens es da saúde mental e à capacidade para o trabalho (vitalidade: p<0,001; aspectos sociais: p=0,055; aspecto emocional: p=0,074; saúde mental: p<0,001 e capacidade para o trabalho: p=0,001). CONCLUS ES: Satisfa o no trabalho está associada à saúde dos trabalhadores nos seus aspectos "saúde mental" e "capacidade para o trabalho", mostrando a importancia dos fatores psicossociais em rela o à saúde e bem-estar dos trabalhadores. Sugerem-se diretrizes para mudan as na organiza o e concep o do trabalho, direcionadas aos aspectos psicossociais. S o recomendados estudos longitudinais para investigar a dire o causal das associa es encontradas.
Microstructural Study of ZnO Nanostructures by Rietveld Analysis
Francisco Pola-Albores,Francisco Paraguay-Delgado,Wilber Antúnez-Flores,Patricia Amézaga-Madrid,Edna Ríos-Valdovinos,Mario Miki-Yoshida
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/643126
Abstract: ZnO nanorods were synthesized by induced seeds by chemical bath deposition using hexamethylenetetramine (HMT) as a precipitant agent and zinc nitrate (ZN) as Zn2+ source at 90°C. The influence of reactants ratio was studied from 2 to 0.25?ZN/HMT molar. The results obtained by scanning electron microscopy confirm that the diameter of nanorods was affected directly by the concentration of both zinc and OH? sources. Nanotubes (hollow nanorods) were obtained with high HMT concentrations and were turning over nanorods as HMT concentration decreased. Microstructural information was obtained by Rietveld refinement of grazing incidence X-ray diffraction data. These results evidence low-textured materials with oriented volumes less than 18% coming from (101) planes in Bragg condition. 1. Introduction Nowadays, the interest in nanostructured ZnO materials has taken more relevance due to its wide range of applications and the scientific interest in polymorphism depending on synthesis conditions. Zinc oxide is a II–VI semiconductor with a band gap of 3.37?eV; it is thermally and chemically stable [1] and presents interesting properties [2–4]. These properties make the ZnO feasible for applications in many field, such as energy conversion [5–7], optoelectronics [8–10] and sensing devices [11–14], in particular when it is synthesized in one-dimensional (1D) geometry [15–17]. Among all the geometries, the most feasible for these types of applications are nanowires [1, 18–20], nanobelts [21, 22], nanotubes and nanorods, and singles or arrays of them [23, 24]. Several methods for the synthesis of nanostructured ZnO have been explored, but some of them are highly power demanding (in temperature or pressure) [25], or they use sophisticated processes to obtain the materials by means of a vapor-liquid-solid mechanisms [26–28], that makes the scaling-up a complicated challenge [29]. One of the most promising methods to synthesize nanomaterials is the chemical bath deposition (CBD), which is a non sophisticated, low-temperature (<100°C), and low-cost wet route [2, 25, 30, 31]. Additionally, CBD has a high degree of versatility to modify several parameters, such as temperature, pH [32], and concentration of reactants; which in turn could modify the morphology, size, and shape of the nanomaterials [33]. In this work, we have synthesized ZnO nanorods by CBD and studied the influence of hexamethylenetetramine (HMT) and zinc concentration in their morphology and microstructure. Additionally, the microstructure analysis was realized with Rietveld refinement, using asymmetric
Evaluating the Relationship between the Banking System Stability and the Internal Capital Adequacy Assessment Process: Evidence from the Egyptian Banking Sector  [PDF]
Karim F. F. Mohamed
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.74020
Abstract: In the repercussions of the latest financial crisis that have occurred on the years 2008-2009, to fortify the stability of the banking systems, policy makers, and the Basel Committee on Banking Supervision—BCBS, together with national regulators have built up a few safety measures, and structures to guarantee that banks establishments keep up adequate capital levels through using risk management tools, in specific the Internal Capital Adequacy Assessment Processes (ICAAP). They all have called for thorough evaluations and assessments for the structure and components of risk management frameworks, tools, and practices whether by banks, regulators, analysts and risk management experts consistently, to ascertain the adequacy of the banking systems, policies, arrangements and techniques for overseeing risks, and guaranteeing the sufficiency of holding appropriate capital levels for confronting normal, as well as adverse and unexpected situations or emergencies. The main objectives of this research study are to shed the light on the ICAAP as one of the main keys of risk management programs, a process by which banks can use to ensure that they operate with an appropriate level of capital, forward looking processes for capital planning covering a broad range of risks across banks, activities beyond simple capital management, and bring together risk and capital management activities in a form that can be used to support business decisions. The research study shall evaluate the significant relationship between the Banking System Stability (dependent variable) and the Internal Capital Adequacy Assessment Process (ICAAP—independent variable) with evidence from the Egyptian Banking Sector.
Creation and Analysis of Earth’s Surface Roughness Maps from Airborne LiDAR Measurements in Downtown Urban Landscape  [PDF]
Fahmy F. F. Asal
Journal of Geographic Information System (JGIS) , 2019, DOI: 10.4236/jgis.2019.112015
Abstract: The Earth’s surface roughness constitutes an important parameter in terrain analysis for studying different environmental and engineering problems. Authors gave different definitions and measures for the earth’s surface roughness that usually depend on exploitation of digital elevation data for its reliable determination. This research aimed at exploring the different approaches for defining and extraction of the Earth’s surface roughness from Airborne LiDAR Measurements. It also aimed at evaluating the effects of the window size of the standard deviation filter on the created roughness maps in downtown landscapes using three known approaches namely; standard deviation filtering of the Digital Elevation Model (DEM), standard deviation filtering of the slope gradient model and standard deviation filtering of the profile curvature model. In this context, different roughness maps have been created from Airborne LiDAR measurements of the City of Toronto, Canada using the three filtering approaches with varying window sizes. Visual analysis has shown color tones of small roughness values with smooth textures dominate the roughness maps from small window sizes of the standard deviation filter, however, increasing the window sizes has produced wider variations of the color tones and rougher texture roughness maps. The standard deviations and ranges of the roughness maps from LiDAR DEM have increased due to increasing the filter window size while the skewness and kurtosis have decreased due to increasing the window size, indicating that the roughness maps from larger window sizes are statistically more symmetrical and more consistent. Thus, kurtosis has decreased by 53% and 82% due to increasing the window size to 7 × 7 and 15 × 15 respectively. The standard deviations of the roughness maps from the slope gradient model have increased due to increasing the window size till 15 × 15 while they have decreased with more increases. However, skewness has decreased due to increasing the window size till 15 × 15 and the kurtosis has decreased with higher rate till window size of 11 × 11. In the roughness maps from the profile curvature model, the ranges and skewness have decreased by 93.6% and 82.6% respectively due to increasing the window size to 15 × 15 while, kurtosis has decreased by 58.6%, 76.3% and 93.76% due to increases in the filter window size to 5 × 5, 7 × 7 and 15 × 15 respectively.
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