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Search Results: 1 - 10 of 316769 matches for " Francisco J.; Cesteros "
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Empleo de una sonda infrarroja in situ para monitorear reacciones de esterificación
Sánchez C.,Francisco J.; Cesteros,Carlos; Katime,Issa A.;
Ingeniería e Investigación , 2006,
Abstract: a batch reactor was employed having ph meter, ir probe and continuous operation detectors so that it could work as a cstr reactor. as esterification advanced, then ir bands corresponding to the carboxyl acid cooh group and the alcohol c-oh group decreased whilst a parallel increase was presented in the ester -coor group band which was forming. reaction progress could be observed by continuous ir spectrum registration. the ir band for hoh (water) could not be studied because it needed a completely anhydrous medium for doing so. standard solutions could be prepared for quantifying ir band peak intensity, according to a component?s composition in the mixture. however, when phase changes occurred in the reaction mixture, this method could not be employed for following the course of a particular reaction because random variation was detected in band intensity.
Empleo de una sonda infrarroja in situ para monitorear reacciones de esterificación Using an infrared probe for in situ monitoring of esterifying reactions
Sánchez Castellanos Francisco José,Cesteros Carlos,Katime Issa A
Ingeniería e Investigación , 2006,
Abstract: Se empleó un reactor batch (por lotes), dotado de tres detectores: pH, Sonda IR y operación en continuo, de tal forma que puede operarse como un reactor CSTR. En la medida en que la esterificación procede, decrecen las bandas correspondientes al grupo -COOH del ácido carboxIlico y la del grupo C-OH del alcohol, presentándose al mismo tiempo incremento en la banda del grupo -COOR del ester que se está formando. El progreso de la reacción se puede seguir por el registro continuo de los espectro IR. La banda correspondiente a H-O-H del agua no se puede seguir ya que se requiere de un ambiente absolutamente anhidro para hacerlo. De otro lado, por aparte pueden prepararse soluciones patrones para poder cuantificar la intensidad de los picos en el espectro IR, segün la composición del componente en la mezcla. Sin embargo, cuando se presentan cambios de fase en la mezcla reactiva, este metodo no puede emplearse para seguir el curso de una reacción, ya que se presenta una variación muy aleatoria en la senal de intensidad de los picos. A batch reactor was employed having pH meter, IR probe and continuous operation detectors so that it could work as a CSTR reactor. As esterification advanced, then IR bands corresponding to the carboxyl acid COOH group and the alcohol C-OH group decreased whilst a parallel increase was presented in the ester -COOR group band which was forming. Reaction progress could be observed by continuous IR spectrum registration. The IR band for HOH (water) could not be studied because it needed a completely anhydrous medium for doing so. Standard solutions could be prepared for quantifying IR band peak intensity, according to a component’s composition in the mixture. However, when phase changes occurred in the reaction mixture, this method could not be employed for following the course of a particular reaction because random variation was detected in band intensity.
La ense anza del espa ol como lengua vehicular en contextos académicos
Susana Pastor Cesteros
MarcoELE : Revista de Didáctica , 2006,
Abstract: La ense anza de segundas lenguas para fines académicos constituye, junto con los profesionales, uno de los dos ámbitos de actuación de la denominada ense anza para fines específicos. En este artículo abordamos las claves del aprendizaje de la lengua meta no ya desde una perspectiva comunicativa general, sino como lengua de instrucción a través de la que los alumnos no nativos, en contexto de inmersión, aprenden las materias de estudio que establece su currículo. Y ello tanto por lo que se refiere al uso de la lengua en el ámbito universitario (tipos de texto, léxico especializado, entornos de aprendizaje), como en el contexto de la ense anza secundaria. En el primer caso, su importancia es indudable, dado el elevado número de estudiantes extranjeros que llegan a nuestras universidades y su previsible incremento con el proceso de convergencia europea. En el segundo, la presente propuesta se inserta en la línea de la ense anza de la lengua a alumnos inmigrantes, si bien en lo que tiene que ver con el aprendizaje del espa ol académico. //// The Second Language Teaching for Academic Purposes represents, along with the professionals, one of the two fields in the Teaching for Specific Purposes. In this paper, I tackle the keys of the language target learning, non in a general communicative perspective, but as the instruction language that the students need to know to learn the content of their curriculum. And this with regard to the use of the language at the university (text types, specialized vocabulary, learning environment) as well as with regard to the Secundary School. On the one hand, in the first case, there is a great number of foreign students who arrive at our universities, fact that will probably increase within the European Higher Education Area. On the other hand, my proposal is included in the second language learning for immigrant students, but only as regards the Academic Spanish Learning.
Are Tent Cities an Illusion of Success? Clients’ Perceptions of Neoliberalism Strategies  [PDF]
Francisco J. Alatorre
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.411010
The term, neoliberalism has been used to describe the overarching political and economic framework in which services for the poor living outside institutional life has operated for roughly the past 30 years. This implies a unified intent to “manage the poor” to benefit the larger society, in particular the business sector and the wealthy which are the key actors in society according to neoliberal doctrine. This paper explores and questions the conventional ideology of “managing the poor” and thus inquires further about the identified objectives of such management: whether such programs are intended to help the homeless re-establish themselves or prevent them from impinging on the wealthier classes. This questioning is done by reporting on and analyzing the experiences of twenty homeless people who are currently being “managed” by services provided by the agency Mesilla Valley Community of Hope (MVCH) in Las Cruces, New Mexico. This agency, reflecting Neoliberal doctrines, has created and manages a tent city which provides services for people who are homeless and near homeless. These services include showers, laundry, mail, voice mail, phone, lockers, case management, training programs, and donated goods, including clothing, shoes, hygiene products and household goods. MVCH also has various housing programs including transitional and permanent housing for people who are homeless. The findings derived from the interviewed participants reveal that “the managed” provide a contrasting view with those who assess neoliberalism practices as only benefiting society.
A note on the Gauss map of complete nonorientable minimal surfaces
Francisco J. Lopez,Francisco Martin
Mathematics , 1998,
Abstract: We construct complete nonorientable minimal surfaces whose Gauss map omits two points of the projective plane. This result proves that Fujimoto's theorem is sharp in nonorientable case.
The Effect of Prices on Risk Aversion  [PDF]
Richard Watt, Francisco J. Vázquez
Theoretical Economics Letters (TEL) , 2012, DOI: 10.4236/tel.2012.21007
Abstract: Traditionally, risk aversion (both absolute and relative) has been expressed as a function of wealth alone. The charac- teristics of risk aversion as wealth changes have been extensively studied. However, prices, as well as wealth, enter the indirect utility function, from which the typical risk aversion measures are calculated. Given that, changes in prices will affect risk aversion, although exactly how has not been considered in the literature. This paper provides such an analysis. In particular, we firstly remind the reader that both absolute and relative risk aversion are homogeneous functions, and as such independently of their particular slopes in wealth, there is a natural effect that holds relative risk aversion constant and decreases absolute risk aversion when prices and wealth are increased by a common factor. We also show that the size of relative risk aversion as compared to the number 1, which is of much importance to the comparative statics of the economics of risk and uncertainty, depends on how changes in prices affect marginal utility. Under plausible (and standard) theoretical assumptions we find that relative risk aversion is likely to be increasing, and that increases in prices will have a tempering effect on risk aversion.
Arch Reconstruction in Hypoplastic Left Heart Syndrome: Handling the Diminutive Aorta  [PDF]
Francisco J. Boye, Frank A. Pigula
World Journal of Cardiovascular Surgery (WJCS) , 2013, DOI: 10.4236/wjcs.2013.36039
Abstract: The diminutive aorta presents technical challenges in the palliation of hypoplastic left heart syndrome. Furthermore, aortic arch caliber changes and variable great vessel relationships can add complexity to an already difficult arch repair. We describe a technical approach that simplifies the aortic reconstruction and makes the procedure more generalizable and reproducible.
Applying Global Perspectives on Fragility to Improve US Communities  [PDF]
Debra J. Bolton, Francisco M. Hernandez
Advances in Anthropology (AA) , 2017, DOI: 10.4236/aa.2017.71003
Abstract: Today, the greatest impacts on families stem from ongoing global conflicts and other natural or man-made disasters. Literature and multi-lingual research were examined and analyzed to determine fragility in rural and urban US communities with high immigrant populations, high poverty, and challenged social integration. Data came from international development and localized research. Literature review content was related to fragility, families emigrating to the US coming from those fragile states, and immigrants’ ability to adapt to new environments as evidenced in research analyses. Approaches that non-governmental, humanitarian and peace-building entities are taking to bridge research with application were also examined. A model of adaptive and culturally-relevant practices is offered as a logical way to address the effects of poverty and fragile conditions, and to move affected populations toward resilience.
Weighted power mean discrete dynamical systems: Fast convergence properties
Francisco J. Solis
Discrete Dynamics in Nature and Society , 2006, DOI: 10.1155/ddns/2006/32685
Abstract: We studied families of discrete dynamical systems obtained by using iteration functions given by weighted power mean in order to understand the role of hyperrapid convergence in nonlinear maps. Our interest resides in concepts related to the velocity of convergence. We introduce new concepts regarding the time of convergence and we provide an ordering of these families according to their dependence on parameters.
Hurricane Footprints in Global Climate Models
Francisco J. Tapiador
Entropy , 2008, DOI: 10.3390/e10040613
Abstract: This paper addresses the identification of hurricanes in low-resolution global climate models (GCM). As hurricanes are not fully resolvable at the coarse resolution of the GCMs (typically 2.5 × 2.5 deg), indirect methods such as analyzing the environmental conditions favoring hurricane formation have to be sought. Nonetheless, the dynamical cores of the models have limitations in simulating hurricane formation, which is a far from fully understood process. Here, it is shown that variations in the specific entropy rather than in dynamical variables can be used as a proxy of the hurricane intensity as estimated by the Accumulated Cyclone Energy (ACE). The main application of this research is to ascertain the changes in the hurricane frequency and intensity in future climates.
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