Procesos de mejora y cambio en una escuela venezolana

El artículo presenta un estudio de caso de un proceso de mejora en una escuela venezolana. Con la finalidad de identificar y describir las políticas y medidas que se pusieron en práctica analizando los efectos y consecuencias de las mismas buscando identificar de igual manera la relación existente entre las políticas y medidas y los cambios percibidos por la comunidad docent

Evaluación técnica-ambiental de un sistema de micro-cogeneración basado en gas natural para aplicación residencial

The study carried out here aims to determine the advantage of using in-situ electricity generation facilities versus conventional generators, being evaluated from the environmental point of view. For this, an environmental analysis on the production of CO2 has been applied to two scenarios of electricity generation for a residential building in Medellin city (Colombia). The first one refers to La Sierra thermo-electric plant located in La Sierra, municipality of Puerto Nare, in the Antioquiashire, which is the most efficient plant in Colombian thermal generation. The second comparison scenario refers to the annual operation of a micro-cogeneration facility, which satisfies the building's hot water and electrical energy needs. Using the capabilities of the TRNSYS v17® energy simulation software and the emission equations available in the public domain, the comparative environmental analysis is carried out between one and the other for the same load. The losses in electric transmission are assumed to be 10%. This analysis has shown a difference of more than 50% in emissions generation, with the main cause being the amount of fuel used, which for both cases is natural gas. On the other hand, this study shows the environmental advantages in the use of in-situ generators, decreasing transmission losses.Evaluación técnica-ambiental de un sistema de micro-cogeneración basado en gas natural para aplicación residencialpublishedVersio

Tridimensional simulation of the speed, pressure and turbulence fields of the air flow on the geometry of a freight truck inside a wind tunnel

This study shows the air flow behavior through the geometry of a freight truck inside a AF6109 wind tunnel with the purpose to predict the speed, pressure and turbulence fields made by the air flow, to decrease the aerodynamic resistance, to calculate the dragging coefficient, to evaluate the aerodynamics of the geometry of the prototype using the CFD technique and to compare the results of the simulation with the results obtained experimentally with the “PETER 739 HAULER” scaled freight truck model located on the floor of the test chamber. The Geometry went through a numerical simulation process using the CFX 5,7. The obtained results showed the behavior of the air flow through the test chamber, and also it showed the variations of speed and pressure at the exit of the chamber and the calculations of the coefficient and the dragging force on the geometry of the freight truck. The evaluation of the aerodynamics showed that the aerodynamic deflector is a device that helped the reduction the dragging produced in a significant way by the air. Furthermore, the dragging coefficient and force on the prototype freight truck could be estimated establishing an incomplete similarity

LANZAMIENTO DE SUPERMERCADOS CHEAP EN VENEZUELA

El presente caso de estudio se plantea en el contexto del sector de distribución de alimentos al detal en Venezuela en los años 2005 al 2007, el cual ha ostentado diversas mutaciones y cambios en función de las condiciones socioeconómicas del país y las tendencias globales. La cadena internacional de Supermercados Cheap, de origen tailandés, es una empresa dedicada a la distribución al menor de productos de consumo masivo, que estaba interesada en abrir operaciones comerciales en Latinoamérica tomando como país piloto a Venezuela. Para ello, quiere desarrollar una red de tiendas con marca y concepto propio adecuada a las características y exigencias del mercado local. En este sentido, debe diagnosticar el escenario de negocios y del mercado actual del sector y diseñar un plan de acción para cumplir con su objetivo.Sector de distribución de alimentos,estrategia de mercadeo, segmentacióny posicionamiento.

Estrategias de prevención en las infecciones asociadas a catéter en recién nacidos: revisión sistemática de la literatura

Las infecciones asociadas a catéter son la primera causa de infección nosocomial descrita en las unidades de cuidado crítico y un control de estas conlleva a disminuir la morbilidad y mortalidad en estos pacientes, tiempos de estancia hospitalaria y aliviar el costo de una hospitalización prolongada para su familia y la sociedad. Objetivo : evaluar la evidencia en las estrategias de prevención de las infecciones asociadas a catéter en recién nacidos. Materiales y métodos : se realizó una búsqueda sistemática en: Cochrane, Pubmed, desde 1995 hasta Abril de 2009. Se seleccionaron revisiones sistmáticas, ensayos clínicos y estudios observacionales. Se utilizó le metodología SIGN para la calificación de los estudios y evaluar el grado de recomendación basada en la evidencia. Resultados : se evaluaron 13 estudios que cumplían con los criterios de inclusión y que respondían a 6 preguntas sobre las diferentes estrategias para la prevención de infecciones asociadas a catéter en recién nacidos. La heterogenicidad de las investigaciones no permitió la realización de metananálisis. Conclusiones : la implementación de un sistema de control y vigilancia en el seguimiento de todos los procesos con mayor atención en todas las medidas de colocación, cuidado y manejo de los catéteres centrales son de forma integral la mejor estrategia en la prevención de infecciones asociadas a catéter en recién nacidos.Vascular catheters are consider fundamental in Neonatal Intensive Care Units and it"s insertion is the most common procedure. 1 Blood related catheter infections (BRCI) are the first nosocomial infection related diseases all purposes to diminished them reduces mobility and mortality, hospitalization and relieves costs for long hospital stays for families and society. 2 There has been many control measures but there are not consensus based on evidence to give general recommendations on this age group. Objective Evaluate evidence on prevention measures for BRCI in newborns. Materials and Methods A systematic search was made at: Cochrane, Pubmed, from 1995 to April 2009. Systematic reviews, randomized controlled trials, case control and cohort studies were analyzed by SIGN evidence methodology. Results Thirteen studies met inclusion criteria and answered to 6 questions about different prevention strategies for blood catheter related infections in newborns. Studies heterogeneity didn"t allow to make methanalysis. Conclusions Implementation of a surveillance protocol in all process with handling catheters seems to be the best strategy on preventing BRCI in newborns

Experimental frequency-dependent rotordynamic coefficients for a load-on-pad, high-speed, flexible-pivot tilting-pad bearing

This thesis provides experimental frequency dependent stiffness and damping coefficient results for a high-speed, lightly loaded, flexible-pivot tilting-pad bearing, with a load-on-pad configuration. Test conditions include four shaft speeds (6000, 9000, 13000 and 16000 rpm), and bearing unit loads from 172 kPa to 690 kPa. The results show that the bearing stiffness is a quadratic function of the frequency of vibration; hence their frequency dependency can be modeled by added-mass terms. The additional degrees of freedom introduced by the pads and the influence of the inertial forces generated in the fluid film account for this frequency dependency. The conventional frequency-dependent stiffness and damping model for tilting-pad bearings is extended with an added-mass matrix to account for the frequency dependency. This approach allows the description of the bearing dynamic characteristics with frequency-independent stiffness, damping and added-mass matrices. Experimental results are compared with predictions from the Reynolds equation and from a bulk-flow Navier-Stokes model. Both models produce good predictions of the stiffness and damping coefficients. However, results show that the bulk-flow model is more adequate for predicting the direct added-mass terms because it accounts for the fluid inertial forces. A bulk-flow solution of the Navier-Stokes equations that includes the effects of fluid inertia should be used to calculate the rotordynamic coefficients of a flexible-pivot tilting-bearing. Static performance measurement results are also detailed. Results include pad metal temperatures, eccentricity-ratios and attitude-angle as a function of bearing load, and estimated power losses

APLICACIÓN DE CÓMPUTO MÓVILY PERVASIVO PARA EL MONITOREO NO INVASIVO DE LA DIABETES EN TIEMPO REAL

Given the alarming increase of people with diabetes in the world, they are looking for different alternatives, using as many available technological resources and thus have an efficient monitoring of this noncommunicable disease (NCD). This paper presents a viable alternative, to have an efficient and non-invasive monitoring, using free software and hardware, such as, Android and Arduino. As well as various non-invasive, such as GSR (Galvanic Skin Response), to measure glucose levels, accelerometers to determine the location of the person body, PulseOximeters, to determine each patient's pulse and GPS sensors, is a Global Positioning System, it helps to have the geographic position of the person. Each of these sensors interact with the system in general, with the purpose of create a pervasive environment, where the user can have a monitoring and control of diabetes and pulse additionally its position and geographical location