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Search Results: 1 - 10 of 28522 matches for " Fernando Espinosa-Fuentes "
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EVALUACIóN EXPERIMENTAL DEL COMPORTAMIENTO DE LA VELOCIDAD DE SEDIMENTACIóN DE PARTíCULAS EXPERIMENTAL EVALUATION OF THE BEHAVIOUR OF THE SEDIMENTATION VELOCITY OF PARTICLES
Gonzalo Salinas-Salas,Fernando Espinosa-Fuentes
Revista Ingenierías Universidad de Medellín , 2012,
Abstract: El presente artículo de investigación presenta los elementos teóricos, la metodología, resultados y conclusiones de un trabajo desarrollado con el fin de determinar el comportamiento de la velocidad de sedimentación terminal de sistemas de partículas no coloidales de tama o medio menor a 1.000 nm respecto de sistemas de partículas de tama o mayor a este. Para esto se analiza el comportamiento del factor de reducción de velocidad terminal de sedimentación. Dada la extrema complejidad de la fenomenología del proceso de sedimentación de sistemas de partículas de diámetros medios menores a 1.000 nm, obliga a que este trabajo tenga un carácter experimental. Los resultados alcanzados mostraron que existe una diferencia entre el comportamiento de la velocidad de sedimentación de sistemas de partículas mayores a 1.000 nm, respecto de los sistemas de partículas cuyo tama o es menor a este, lo que impacta en el valor que adopta el factor de corrección. This article presents the theoretical aspects, methodology, results and conclusions of a study developed to determine the behavior of the terminal settling velocity of noncolloidal particles systems of average sizes smaller than 1,000 nm in comparison to larger particles system. In order to do this, an analysis of the behavior of the reduction factor of terminal velocity of sedimentation was made. Due to the extreme complexity of the phenomenology of the sedimentation process of average particles systems in diameters smaller than 1,000 nm, an experimental work was required. The results indicate that there is a difference between the behavior of the velocity settling of particle systems greater than 1,000 nm, for systems of particles which size is smaller than this, what impacts the value that takes the correction factor.
Determinación del Exponente de la Función de Obstrucción para Partículas Sub-Micrométricas No Coloidales
Salinas-Salas,Gonzalo; Espinosa-Fuentes,Fernando; Babick,Frank; Stintz,Michael;
Información tecnológica , 2009, DOI: 10.4067/S0718-07642009000200004
Abstract: this paper describes an experimental study based on the norm din 66111 and centrifugal analysis of particle with diameters less than 200 nm. the hindrance function of sedimentation velocity presented by richardson and zaki (1954), in which the porosity of a suspension that depends on the draining regime of fluid over a particle is an exponential function, is used. for reynolds numbers smaller than 0.25, the value of the exponent is constant and equal to 4.65. this value does no take into account the increment of the electrochemical forces and the diffusion effects acting on particles with non-colloidal sub-micron diameters. the results show that the hindrance function exponent for this type of system is different from that used by richardson and zaki.
Determinación del Exponente de la Función de Obstrucción para Partículas Sub-Micrométricas No Coloidales Determination of the Hindrance Function Exponent for Noncollodial Sub-Micrometer Particles
Gonzalo Salinas-Salas,Fernando Espinosa-Fuentes,Frank Babick,Michael Stintz
Información Tecnológica , 2009,
Abstract: Se presenta un estudio experimental empleando la Norma DIN 66111 y una centrífuga analítica sobre sistemas de partículas no coloidales cuyos diámetros son menores a 200 nm. Se usó la función de obstrucción de velocidad planteada por Richardson y Zaki (1954), quienes propusieron una ecuación donde la porosidad de una suspensión elevada a un exponente determina la velocidad de sedimentación de las partículas que lo conforman. Para números de Reynolds menores a 0.25, el valor del exponente es constante e igual a 4.65. Este exponente no considera el fuerte incremento de las fuerzas electroquímicas y los efectos difusivos que se presentan sobre partículas con diámetros de orden sub-micrométrico no coloidales. Los resultados alcanzados muestran que el valor que adopta el exponente de la función de obstrucción de velocidad para este tipo de sistemas de partículas es diferente al empleado por Richardson y Zaki. This paper describes an experimental study based on the norm DIN 66111 and centrifugal analysis of particle with diameters less than 200 nm. The hindrance function of sedimentation velocity presented by Richardson and Zaki (1954), in which the porosity of a suspension that depends on the draining regime of fluid over a particle is an exponential function, is used. For Reynolds numbers smaller than 0.25, the value of the exponent is constant and equal to 4.65. This value does no take into account the increment of the electrochemical forces and the diffusion effects acting on particles with non-colloidal sub-micron diameters. The results show that the hindrance function exponent for this type of system is different from that used by Richardson and Zaki.
Vertical distribution of zooplankton biomass and ichthyoplankton density during an annual cycle on the continental shelf of the southern Gulf of Mexico
Espinosa-Fuentes,María de la Luz; Flores-Coto,César; Sanvicente-A?orve,Laura; Zavala-García,Faustino;
Revista de biología marina y oceanografía , 2009, DOI: 10.4067/S0718-19572009000200020
Abstract: seasonal zooplankton biomass (zb) and ichthyoplankton density (id) in the water column on the continental shelf of the southern gulf of mexico were analyzed to determine their vertical distribution patterns and assess if there is a relationship between both components. five depth levels were sampled: 0-6, 6-12, 12-18, 45-55 and 95-105 m. the vertical distribution patterns of zb and id were similar for all sampling seasons, with the greatest concentration of organisms in the upper levels and the lowest at deeper levels. these results suggest that the water column in the study area may be divided into a surface layer (0-18 m) and a deep layer (45-100 m), and seasonal differences may be attributed to mixing processes. the difference between the surface and the deep layers occurs because, in general, the upper layer is the most productive sector of the water column. the relationship between zb and id in the water column was positive and significant (ancova, p<0.05) throughout the sampling seasons for most depths, probably because the production cycle is continuous in the southern gulf of mexico, as is common in tropical and subtropical areas, and it maintains the availability of food, and consequently the predator-prey relationships. the relationship between the zb and the id in the water column is mainly affected by the seasonal variations in the continental water discharges and the mixing processes.
Larval abundance variation of Bregmaceros cantori Milliken & Houde, 1984, related to the El Ni?o events (1987-1996), southern Gulf of Mexico
Flores-Coto,César; Zavala-García,Faustino; Funes-Rodríguez,Rene; Espinosa-Fuentes,María de la Luz; Zavala-Hidalgo,Jorge;
Revista de biología marina y oceanografía , 2008, DOI: 10.4067/S0718-19572008000100009
Abstract: the influence of the el ni?o southern oscillation (enso) on the abundance variation of fish larvae of bregmaceros cantori in the southern gulf of mexico was analyzed. the study was conducted between 1987 and 1996, using 20 oceanographic cruises. the larval abundance of b. cantori was related to: (1) the sea surface temperature anomaly (ssta) in the central equatorial pacific ocean; (2) the average temperature surface layer, to 30 m, obtained from cruises data; (3) the continental water discharges data from the continental hydrological station nearest to the study area. the variability of b. cantori larval abundance was high throughout the sampling period and no seasonal pattern was detected. during the study period, three events of el ni?o occurred: in 1987, 1992 and 1995. statistical analyses indicated significant differences of the larvae abundance of b. cantori between el ni?o and normal years, i.e, years without el ni?o. high abundances of fish larvae were found during el ni?o years. higher abundances of b. cantori larvae, during el ni?o years, are possibly associated to predator-prey relationships
The social role of education: reflections on the mobilization of dentistry students at the University of Talca
Fernando Fuentes
Mouth , 2016, DOI: 10.5281/zenodo.154283
Abstract: This personal reflection was written following the student protests which took place during the first semester of 2016 at the University of Talca, where like other universities in the country, the symptoms of an increasingly serious problem are being felt on a daily basis. Many students are experiencing a similar situation, as education in Chile is in a state of crisis, and dentistry is no exception.
Rol social de la educación: reflexiones desde la movilización de los estudiantes de odontología de la Universidad de Talca
Fernando Fuentes
Mouth , 2016, DOI: 10.5281/zenodo.154284
Abstract: La presente reflexión personal se genera en el marco de la movilización estudiantil que tuvo lugar en la Universidad de Talca durante el primer semestre de 2016, donde al igual que en varias universidades del país, se sienten a diario los síntomas de un gran problema existente. La crisis de la educación es una realidad compartida por muchos en Chile y a esto no queda ajena la odontología.
Network Performance Evaluation with Real Time Application Ensuring Quality of Service with NS2
Luis Fernando Espinosa Moreno
International Journal of Next-Generation Networks , 2012,
Abstract: The quality of service is a need in recent computer network developments. The present paper evaluatessome characteristics in a proposed network topology such as dropped packets and bandwidth use, usingtwo traffic sources, firstly a VoIP source over an UDP agent, then a CBR traffic source over an UDP agentas well as the previous one. Two possible configurations are proposed, implementing both of them in theNetwork Simulator, and implementing in one of them differentiated services to compare the results.Statistics results are shown, in both cases showing the accumulative dropped packet number and thethroughput in the link, obtaining a reducer number of dropped packets in the stage with differentiatedservices, and an improvement in the bandwidth use.
La moral, la ética y la bioética como limitantes sociales a la protección de las invenciones por la vía de las patentes
Fuentes Pinzón,Fernando;
Frónesis , 2006,
Abstract: the purpose of this research is to demonstrate the relationship between morality, ethics, bioethics and the protection of inventions through patents, for which a study of comparative law was carried out on the legislation in this area, with special emphasis on latin-american legislation, and with the intention of verifying the constant presence of invention patent rights in latin american in relation to bioethical notions which limit the protection of inventions contrary to the same, and the coincidence among conventions of exclusion based on moral or bioethical reasons.
La protección del autor de obras plásticas en Venezuela
Fuentes Pinzón,Fernando;
Revista de Ciencias Sociales , 2007,
Abstract: the protection and growth of plastic arts is a necessity that all states must transcend over time in order to create a favorable legal environment that benefits the creators of such art works. this paper analyzes the protection that venezuelan legislation offers in relation to this topic, as well as rights conceded and their loopholes, for the purpose of presenting in one overall article, the judicial framework for the protection of art and artists. the research is documentary, emphasizing the study of venezuelan norms, as well as latin american norms in relation to authors rights and related topics. the conclusion is that national protection is coincident with modern doctrine and legislation in other countries, however the difference resides in the application and management of authors rights in a united or group format, since this is observed to be disperse and disorganized.
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