WorldWideScience

Sample records for vapor las turbinas

  1. Effect of the blades and seals system wear on steam turbine efficiency and power; Efecto del desgaste del sistema de alabes y sellos sobre la eficiencia y potencia de las turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The implementation of a method for steam turbine evaluation through the measured geometry in the flow channel and its operating conditions, is presented. This method, previously developed, allows the identification and quantification of the power and efficiency loss due to the wear of its elements (worn or bent blades, worn seals, deposits, etc.); the benefit that is obtained is a more precise knowledge on the turbine behavior and a basis is acquired to give priority to the maintenance work, from the stand point of energy utilization. In this paper, the power and efficiency loss of a 300 MW steam turbine is located and evaluated, a sensibility analysis is presented for the typical elements that cause the deterioration of the efficiency in this type of turbines. [Espanol] Se presenta la implementacion de un metodo de evaluacion de turbinas de vapor a partir de la geometria medida del canal de flujo y sus condiciones de operacion. Este metodo, previamente desarrollado, permite identificar y cuantificar las perdidas de potencia y eficiencia debido al desgaste de sus elementos (alabes desgastados o doblados, sellos desgastados, depositos, etcetera); el beneficio que se obtiene es un conocimiento mas preciso del comportamiento de la turbina y que se tiene una base para dar prioridad a los trabajos de mantenimiento desde el punto de vista de aprovechamiento de la energia. En este articulo se localizan y evaluan las perdidas de potencia y eficiencia de una turbina de vapor de 300 MW, ademas, se presenta un analisis de sensibilidad para los elementos tipicos que originan el deterioro de la eficiencia en este tipo de turbinas.

  2. Useful life extension of steam-turbine elements by means of welding processes; Extension de la vida util de los elementos de las turbinas de vapor mediante procesos de soldadura

    Energy Technology Data Exchange (ETDEWEB)

    Mazur Czerwiec, Zdzislaw; Cristalinas Navarro, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1994-03-01

    The elements of the flow system in the steam turbines are subjected to a natural or accelerated wear during their operation. The stationary and the rotating blades are parts of the turbine that present damages, faults or materials wear, after some service periods, that can be from mechanical or metallurgical origin and prevent its continuous operation. This is also revealed in the equipment availability, reliability and performance diminution. Several cases are presented of recovery, and useful life extension of worn stationary blades (nozzle blocks and diaphragms), and rotating blades by means of welding processes executed in several fossil fuel power plants of Comision Federal de Electricidad. For each specific case, wear type or damage, the special processes based in welding processes, were developed. The blade recovery process also includes: the stress relieving, machining, special coating, quality control and tool design. Once the recovery process is completed, the components were installed back in the turbines for their utilization. The application of the welding technologies developed for blade recovery, represents just a fraction of the cost of new blades, that results in an economic saving. [Espanol] Los elementos del sistema de flujo de las turbinas de vapor sufren un desgaste natural o acelerado durante su operacion. Los alabes fijos y moviles son las partes de la turbina que despues de ciertos periodos de servicio presentan danos, fallas o desgaste del material que pueden ser de origen mecanico o metalurgico y no permiten su operacion continua. Esto se refleja tambien en la disminucion de la disponibilidad, confiabilidad y rendimiento del equipo. Se presentan varios casos de recuperacion y prolongacion de la vida util de alabes fijos (bloques de toberas y diafragmas) y moviles danados y gastados a causa de procesos de soldadura que se llevaron a cabo en varias plantas termoelectricas de la Comision Federal de Electricidad. Para cada caso especifico

  3. Theorical and experimental study of the induced forces by the mixed, divergent, convergent and straight labyrinth of seal systems on the steam turbines, gas turbines and compressor rotors; Estudio teorico-experimental de las fuerzas inducidas por los sistemas de sellos de laberinto rectos, convergentes, divergentes y mixtos sobre los rotores de turbinas de vapor, turbinas de gas y compresores

    Energy Technology Data Exchange (ETDEWEB)

    Salazar San Andres, Octavio Ramon

    1991-12-31

    demuestran que el modelo es capaz de dar una vision cualitativa y cuantitativa de las fuerzas y los coeficientes de rigidez y amortiguamiento de los sellos de laberinto con las geometrias antes mencionadas, tanto para el rotor estatico como en operacion. Por otra parte se recomienda llevar a cabo mas experimentacion con equipo instalado en plantas termoelectricas y en especial en turbinas de vapor con capacidades iguales o superiores a los 300 MW, donde las altas presiones y los sellos localizados en la parte superior de los alabes, vuelven mas susceptibles a las maquinas para autoinducir vibraciones subsincronas.

  4. Condensers for measuring steam quality at the inlet of back-pressure units of the Los Azufres, Mich., geothermal field; Condensadores para medir la calidad del vapor a la entrada de las turbinas a contrapresion del campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval Medina, Fernando; Gonzalez Gonzalez, Rubi; Reyes Delgado, Lisette; Medina Martinez, Moises [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia de Los Azufres (Mexico)]. E-mail: fernando.sandoval@cfe.gob.mx

    2007-01-15

    Electrical conductivity is an indirect measurement of the quality of the steam supplied to power units. In the Los Azufres, Mich., geothermal field, the electrical conductivity once was measured in a discrete and periodic way by condensing steam samples through a water-cooled condenser. In an attempt to continuously measure conductivity, conductivity meters were installed where the units discharged, but the values proved unstable and unrepresentative. Thereafter, taking into account that steam quality should be measured at the steam delivery-reception point, equipment was designed and tested for continuously condensing steam. Finally it was possible to get an air-cooled condenser able to condense 500 milliliters per minute, enough to collect a representative flow of the steam and to measure its electrical conductivity. The equipment was installed in all seven back-pressure units operating in the field and to date has been operating in an optimal manner. [Spanish] La conductividad electrica es una medida indirecta de la calidad del vapor que se suministra a las unidades turbogeneradoras. En el campo geotermico de Los Azufres, Mich., la conductividad electrica se media en forma puntual y periodica, condensando muestras de vapor por medio de un serpentin enfriado con agua. Despues, ante la necesidad de medirla en forma continua, se instalaron conductivimetros en las descargas de las unidades, pero los valores resultaron muy inestables y poco representativos. Considerando, ademas, que la calidad del vapor debe medirse en el punto de entrega-recepcion, se disenaron y probaron equipos para condensar vapor de manera continua, lograndose construir un condensador enfriado por aire que logra condensar un flujo de 500 mililitros por minuto, cantidad suficiente para tener un flujo representativo del vapor que alimenta a las turbinas y medirle su conductividad electrica. Se instalaron estos equipos en las siete unidades turbogeneradoras a contrapresion que funcionan en el campo

  5. Determination of forces induced by steam flow in turbines; Determinacion de fuerzas inducidas por flujo de vapor en turbinas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Castrejon, Juan Carlos

    2008-09-15

    blades, has a harmonic pattern. The pressure field variation as time function is uniform: the peaks and valleys across the axial clearance are always in phase. However the instant picture of the pressure field it's different: the peaks and valleys are not in phase and the number of peaks and valley changed across the clearance. In the case of the forces acting on blades, a Fourier on the forces calculated was used to determine the coefficients and frequency of a Fourier equation which can be used to calculate the alternating stresses on the blade in order to predict the useful life blades. [Spanish] Las vibraciones inducidas por flujo de vapor en turbinas representan uno de los problemas que enfrenta la operacion de turbinas de vapor cuya capacidad rebasa los 300 MW. Ademas estas constituyen uno de los limites tecnologicos para el desarrollo de turbinas de vapor de mas de 1 GW. Este tipo de fenomeno tiene su origen en la interaccion del rotor con el fluido que se encuentra en sus proximidades. El flujo de vapor dentro de la turbina es complejo, ya que es turbulento e inestable. A medida que el flujo pasa una etapa de estator o de rotor, se generan secundarios, vortices en los filos de salida, estelas con caracteristicas de flujo diferentes al flujo principal en los pasajes. Estas variaciones en el flujo son las que inducen vibraciones forzadas en los alabes. Ademas existen varios factores que contribuyen a la aplicacion de vibraciones en alabes inducidas por flujo como son: inestabilidad del flujo de vapor en los claros de los sellos, secuencia de apertura de las valvulas, estelas de las toberas, obstrucciones en algunas de las toberas y diferente espaciamiento en las toberas. Las vibraciones por flujo pueden ser peligrosas si su frecuencia coincide con la frecuencia natural del sistema, provocando efectos mas nocivos que las vibraciones por desbalance o por desalineamiento, pues tienen amplitudes mas grandes y provocan esfuerzos alternantes en los componentes del

  6. The online diagnosis of steam turbines; El diagnostico en linea de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. Antonio; Rivera G, Juan J; Cristalinas N, Victor M; Marino L, Carlos A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    de mantenimiento requeridas para retornar la unidad a su mejor condicion de trabajo. En este articulo se describe la metodologia para la evaluacion termica en linea de las turbinas de vapor y de sus equipos auxiliares de transferencia de calor: condensador y calentadores de agua, y se presentan algunos de los resultados obtenidos.

  7. Automatic diagnosis of steam turbines in line; Diagnostico automatico de turbinas de vapor en linea

    Energy Technology Data Exchange (ETDEWEB)

    Pensado Vassallo, Enlai

    2008-05-15

    o confiabilidad. De esta manera, siendo la energia nuclear la unica alternativa viable para sustituir la quema de combustibles fosiles en plantas termoelectricas, con antecedentes como el accidente de Three Mile Island en 1979 o el desastre de Chernobil en 1986, han llevado a no despreciar los riesgos relacionados. Lo cual complica su manejo y en consecuencia ha limitado la proliferacion de mas centrales nucleares. Bajo esta realidad, la problematica se concentra en dos tares: aumentar el rendimiento de las plantas termoelectricas y reducir la emision de contaminantes, tanto gases como liquidos. Por todo esto, y en cumplimiento con los valores expresados en la mision y vision del Instituto de Investigaciones Electrica (IIE), se ha seleccionado desarrollar una herramienta de apoyo para el estudio del estado de equipos rotativos remotos. Para ello, tomando como base la experiencia del IIE en el diagnostico de turbinas de vapor, se ha desarrollado una plataforma capaz de determinar la presencia de fallas a traves del modelado de la turbina y sus elementos, se representa el comportamiento esperado y, mediante la transformacion de las senales recolectadas del sistema, se calcula el comportamiento real del equipo. Con ambos resultados se procede a aplicar una tecnica de diagnostico que permita detectar las desviaciones e inferir los desperfectos existentes. Buscando mejorar la certeza y calidad de los resultados del analisis, como complemento, se ejecuta revision de las reglas de diagnostico, con base en el registro historico de diagnosis realizada y empleando un algoritmo genetico para la inclusion de reglas nuevas, las cuales se evaluan como candidatas para la mejora del producto. Este documento representa los esfuerzos de mas de un ano en el area de diagnostico, en busca de la adecuada arquitectura para una infraestructura de diagnostico remoto que permita la deteccion de fallas en centrales con turbina de vapor. El principal reto de crear esta infraestructura es la

  8. Analysis and control of erosion by solid particles in the elements of the flow system of steam turbines; Analisis y control de erosion por particulas solidas en los elementos del sistema de flujo de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Mazur Czerwiec, Zdzislaw; Campos Amezcua, Alfonso; Campos Amezcua, Rafael [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2010-07-01

    The analysis of erosion by solid particles is presented of different elements of the flow channel of the steam turbines that operate in Mexico: nozzles, stop valves, blade bosses, labyrinth seals and rotor disc; using tools of of Computational Fluid Dynamics (CFD). In these main elements of turbines a strong problem of erosion was registered that threatens the reliable operation of the turbines, its availability and its optimal yield. With base on the results of the numerical analyses, the design modifications of the different elements were developed from the flow channel of the steam turbines, in order to reduce the erosion and thus diminishing the energy losses and increasing the steam turbine efficiency. This work presents the main benefits that the Thermoelectric Power Plants obtain with the reduction of the erosion by solid particles that affect the critical components of steam turbines: extension of the period between maintenance, replacement of components, reduction of operation and maintenance costs of the turbines, and extension of the useful life of the main components. [Spanish] Se presenta el analisis de erosion por particulas solidas de diferentes elementos del canal de flujo de las turbinas de vapor que operan en Mexico: toberas, valvula de paro, tetones de los alabes, sellos de laberinto y disco del rotor; utilizando herramientas de Dinamica de Fluidos Computacional (DFC). En estos elementos principales de turbinas se registro un fuerte problema de erosion que amenaza la operacion confiable de las turbinas, su disponibilidad y su rendimiento optimo. Con base en los resultados de los analisis numericos, se desarrollaron las modificaciones de diseno de los diferentes elementos del canal de flujo de las turbinas de vapor, con el proposito de reducir la erosion y asi, disminuir las perdidas de energia e incrementar el rendimiento de las turbinas de vapor. Este trabajo presenta los principales beneficios que obtienen las Centrales Termoelectricas con la

  9. Reparación por soldadura de rotores de turbinas de vapor y de gas fabricados con aceros al Cr-Mo-V

    Directory of Open Access Journals (Sweden)

    Mazur, Z.

    1999-04-01

    Full Text Available An analysis of typical steam turbine and gas turbine rotor failures is carried out. On the base of the rotors different failure causes and their mode of occurring, an evaluation of the weldability of the Cr-Mo-V steels and the classification of the common turbine rotors repair possibilities is presented. The developing of specific in-situ welding repair process of the damaged 20.65 MW gas turbine rotor is described. After repair, the rotor was put back into service.

    Se presenta un análisis de daños típicos en rotores de turbinas de vapor y de gas fabricados con aceros de baja aleación al Cr-Mo-V. Partiendo de las causas y modos de presentación de los fallos y el deterioro del material de los rotores durante la operación de la turbina, se lleva a cabo un análisis de la soldabilidad de los aceros al Cr-Mo-V y se presenta una clasificación de los posibles tipos de reparaciones de los rotores de turbinas. Con base en los daños presentados en el rotor de la turbina de gas de 20,65 MW, se presenta el desarrollo de la tecnología de reparación por soldadura llevada a cabo in situ. El rotor fue puesto nuevamente en servicio después del proceso de reparación.

  10. Useful life extension of steam turbine rotors; Alargamiento de la vida en rotores de turbina de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Arelle, Carlos [Turbomaquinas S. A. de C.V., La Piedad, Michoacan (Mexico)

    2007-11-15

    The continuous use of steam turbines, the chemistry of the steam itself and the variations of operation velocities, cause the gradual deterioration by erosion, oxidation and/or corrosion of the rotors and blades. When this happens most of the original manufacturers recommend to rectify the areas, diminishing the surfaces, or to compare with a new rotor. TURBOMAQUINARIAS S.A. de C.V. has developed the most reliable and safe methods to return the rotor to its original dimensions and in case of recurrent problems such as erosion, oxidation and/or wear, it offers the alternative of attaching coatings metallurgically compatible with which these problems are eliminated or diminished that might show up on the rotor surface as well as in the body of the discs or of the blades. These restoring methods are recommended by the international standards such as API 687. [Spanish] El uso continuo de las turbinas de vapor, la quimica del mismo vapor y la variacion de las velocidades de operacion, ocasionan el deterioro gradual por erosion, oxidacion y/o corrosion de los rotores y de los alabes. Al ocurrir esto la mayoria de los fabricantes originales recomiendan rectificar las areas, disminuyendo las superficies, o bien comparar un rotor nuevo. TURBOMAQUINARIAS S.A. de C.V. ha desarrollado los metodos mas confiables y seguros para devolver a su rotor las dimensiones originales y en caso de problemas recurrentes tales como erosion, oxidacion y/o desgaste, ofrece la alternativa de agregar recubrimientos metalurgicamente compatibles con los cuales se eliminan o se disminuyen estos problemas que pueden presentarse tanto en la superficie del rotor como del cuerpo de los discos o bien de los alabes. Estos metodos de restauracion son recomendados por las normas internacionales tales como la API 687.

  11. Evaluation of the useful life of steam turbine rotors; Evaluacion de vida util de rotores de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Carnero Parra, Antonio; Garcia Illescas, Rafael; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    This article presents the methodology applied by the Management of Turbomachinery of the Institute of Investigaciones Electricas (IIE), for the evaluation of the remaining useful life of steam turbine rotors in the phase of initiation of fissures. The evaluation of the remaining useful life of turbines, will reveal the real state of health of the rotor and will serve as a base for the future decision making that guarantees their structural integrity. [Spanish] El presentes articulo presenta la metodologia aplicada por la Gerencia de Turbomaquinaria del Instituto de Investigaciones Electricas (IIE), para la evaluacion de la vida util remanente de rotores de turbinas de vapor en la fase de iniciacion de fisuras. La evaluacion de la vida util de turbinas, revelar el estado real de salud del rotor y servira de base para la toma de decisiones futuras que garanticen su integridad estructural.

  12. El Impacto Acústico de las Turbinas Eólicas sobre las Personas y Colectivos: Métodos de Evaluación y Control

    OpenAIRE

    Aguilar García, María José

    2012-01-01

    En este trabajo se estudia el impacto acústico que las turbinas eólicas tienen sobre personas y colectivos. Para ello se analizan los efectos de las turbinas eólicas sobre las personas. En concreto qué características hacen especialmente molesto a este ruido y qué efectos provoca en la salud de las personas (desde las molestias comunes y trastornos del sueño hasta otros efectos consecuencia de los anteriores). Finalmente se aborda la percepción de los infrasonidos y sus efectos sobre seres...

  13. Thermodynamic performance of gas turbine; Comportamiento termodinamico de las turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Lugo Leyte, Raul [Universidad Autonoma Metropolitana-Iztapalapa, Mexico D.F. (Mexico); Velazquez Toledo, Miguel; Hernandez Fernandez, Angel [Escuela Superior de Ingenieria Mecananica y Electrica, Academia Mecanica, Instituto Politecnico Nacional, Mexico D.F. (Mexico); Torres Aldaco, Alejandro [Universidad Autonoma Metropolitana-Iztapalapa, Mexico D.F. (Mexico)

    2003-01-15

    This work presents a computer code developed to simulate thermodynamic performance of a gas turbine cycle. The predicted performance is determined by measurements, in terms of various thermodynamics performance parameters which are defined and discussed in this paper. These parameters include the output, efficiency, fuel flow rate and air flow rate in relation to variations in the ambient temperature, pressure ratio, turbine entry temperature, compressor isentropic efficiency and turbine isentropic efficiency. [Spanish] Se presenta el comportamiento termodinamico de las centrales termicas que operan con turbinas de gas al variar los siguientes parametros: condiciones ambientales, relacion de presiones, temperatura de los gases a la entrada de la turbina de gas y las eficiencias isentropicas de compresion y expansion. Los resultados obtenidos son la eficiencia termica, el trabajo motor generado, el exceso de aire y los flujos de combustible en funcion de los parametros citados anteriormente. El analisis parametrico se realizo con el simulador TURBOGAS disenado en el laboratorio de ingenieria termica e hidraulica aplicada de la seccion de estudios de posgrado e investigacion de la escuela superior de Ingenieria Mecanica y Electrica del Instituto Politecnico Nacional.

  14. Repair by weld of steam and gas turbine rotors made of Cr-Mo-V steel; Reparacion por soldadura de rotores de turbinas de vapor y de gas fabricados con aceros al Cr-Mo-V

    Energy Technology Data Exchange (ETDEWEB)

    Mazur C, Zdzislaw; Hernandez R, Alejando [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Orozco S, Julian; Banuelos P, Jose E. [Comision Federal de Electricidad (Mexico)

    2003-07-01

    In this article an analysis is presented of the typical damages in steam and gas turbine rotors made of Cr-Mo-V low alloy steels. An analysis of the weldability of the Cr-Mo-V steel is carried out and a classification of the possible types of repairs of the turbine rotors is presented, starting off from the causes and ways of presentation of the faults/deterioration of the rotor materials during the operation of the turbine. With base on the damages detected in the rotor of a gas turbine of 20.65 MW, the development of the repairing technology carried out by weld in site is presented. After the repair process, the rotor was put again in operation. [Spanish] En este articulo se presenta un analisis de los danos tipicos en rotores de turbinas de vapor y de gas fabricados con aceros de baja aleacion al Cr-Mo-V. Se lleva a cabo un analisis de la soldabilidad de los aceros al Cr-Mo-V y se presenta una clasificacion de los posibles tipos de reparaciones de los rotores de turbinas, partiendo de las causas y modos de presentacion de las fallas/deterioro del material de los rotores durante la operacion de la turbina. Con base en los danos detectados en el rotor de una turbina de gas de 20.65 MW, se presenta el desarrollo de la tecnologia de reparacion por soldadura llevada a cabo en sitio. Despues del proceso de reparacion, el rotor fue puesto nuevamente en servicio.

  15. Reliability of electric generation units by evaluating the loss of power and efficiency of turbines; Confiabilidad de las unidades de generacion electrica mediante la evaluacion de la perdida de potencia y eficiencia de las turbinas

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Solis, Jose Antonio; Cristalinas Navarro, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2012-07-01

    The aim of the specialized technical service to evaluate the loss of power and efficiency of an open steam turbine is to quantify these losses caused by the deterioration of internal seals, deterioration of the steam path geometry components (nozzles and blades) and increased roughness of the blades and nozzle surface due to erosion (steam, humidity and impacts) and, also, due to salts deposition. In the same way, to establish a set of recommendations, in order of importance by the attention of the Power Plant with the purpose of recovering the major quantity of power and efficiency lost by the steam turbine and assurance, by means of technical supervision of the activities set in the recommendations, and in accordance with CFE rules, international standards and the personal experience of the Instituto de Investogaciones Electricas (IIE), staff, an acceptable quality in rehabilitation of mechanical components such as the maintenance of the steam turbine itself. Using an application example, this paper describes, the methodology of execution of this kind of services. Also, the quality of the maintenance and the rehabilitation of the steam turbine components are quantified. [Spanish] El objetivo del servicio tecnico especializado para evaluar la perdida de potencia y eficiencia de una turbina de vapor abierta es cuantificar dichas perdidas a causa del deterioro de los sellos internos, del deterioro la geometria de referencia de los componentes del canal de vapor (alabes fijos y alabes moviles) y del aumento de la rugosidad de la superficie de los alabes a causa de la erosion (marcas de vapor, de humedad y de impactos) y de la deposicion de sales. Asimismo, establecer una serie de recomendaciones en orden prioritario para la atencion de la central, con el fin de recuperar la mayor parte de la potencia y eficiencia perdidas por la turbina y asegurando, mediante la supervision tecnica de las actividades resultantes de las recomendaciones y conforme a la normativa de la

  16. Robust velocity and load control of a steam turbine in a combined cycle thermoelectric power station; Control robusto de velocidad y carga de una turbina de vapor en una central termoelectrica de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Archundia, Enrique

    1998-12-31

    of the computation, the programming languages and the numerical methods allow to develop mathematical models that simulate in an approximate manner the processes to control, as it is the case of the combined cycle thermoelectric power station and in this way making the evaluation of algorithms of modern control possible. In chapter I a functional description of the steam turbine process is given. Since this belongs to a combined cycle thermoelectric power station, it is begun with the description of this power station, later to emphasize the subsystem of the steam turbine and emphasize each one of the elements that comprise this last one. [Espanol] Este trabajo de investigacion esta orientado a disenar, desarrollar y validar un algoritmo de control moderno, que permita la obtencion de mejores desempenos en el control de velocidad de una turbina de vapor perteneciente a una central termoelectrica de ciclo combinado, en todo el intervalo de operacion, asi como la obtencion de mejores desempenos en el control de la cantidad de megawatts generados por la misma cuando esta acoplada a un generador electrico, comparando el desempeno con el obtenido mediante el controlador convencional existente. Los cambios en la referencia de velocidad o carga, son a solicitud del operador y se dan siempre en forma de rampa, indicando la rapidez con la que se desea efectuar el cambio de valor en la referencia. Esta es la razon por la cual el objetivo principal del control a disenar es realizar un buen seguimiento a referencias del tipo rampa. En el subsistema de la turbina de vapor existente el inconveniente de que las valvulas que regulan el flujo de vapor hacia la turbina, presentan un acoplamiento con la valvula del bypass que permite derivar el flujo de vapor hacia el condensador principal sin tener que pasar por la turbina. Es por esto que se propone un control multivariable que contemple la interaccion que se presenta entre las valvulas antes mencionadas, partiendo de un diseno

  17. Análisis técnico-económico del cambio de turbinas de vapor por motores eléctricos en tandem de molinos del ingenio la troncal

    OpenAIRE

    Molina Idrovo, Luis Angel; Matute Fernandez, Jose Manuel; Cueva Urgilez, Alvaro Enrique

    2009-01-01

    El Ingenio La Troncal desde el año 2005 entrega sus excedentes de energía eléctrica al Mercado Eléctrico Mayorista, esto representa ingresos económicos para la empresa. Con el fin de incrementar dichos excedentes se debe hacer un cambio importante dentro de la planta; el área de molienda consta de 6 molinos y 3 picadoras de caña impulsadas por 9 turbinas de vapor y con el fin de utilizar el vapor en generación eléctrica se reemplazaran estas turbinas por motores eléctricos de a...

  18. Vibration analysis and online thermodynamic assessment of a turbo-blower turbine; Analisis de vibraciones y evaluacion termodinamica en linea de la turbina de un turbosoplador

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Q, Rodolfo; Marino L, Carlos; Ramirez S, Jose A.; Rivera G, Juan J. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    In this paper are presented the results of the analysis of dynamic and thermodynamic behavior analysis of a turbo-blower integrated by one 13,080 KW steam turbine and a blower with a flow of 131,520 ft{sup 3}/m, to determine the cause of the excessive wearing of the axial trust bearing of the steam turbine. The main cause of failure is the wearing and severe dirtiness of the turbine stages that contributes with an increment of the turbine axial load. The consequences of the turbine deterioration are: greater axial load due to the additional heating rotor (requires greater steam to generate the same power that in design conditions); turbine motive power reduction and the reduction of isentropic efficiency of the same, for similar average steam consumption between reference and test. Due to the former the turbine power represents a deviation of the 34.74% in Steam Specific Consumption (SSC). [Spanish] Se presenta los resultados del analisis del comportamiento dinamico y termodinamico de un turbosoplador integrado por una turbina de vapor de 13,080 KW y un soplador con un caudal de 131,520 pies{sup 3}/m, para determinar la causa del desgaste excesivo de la chumacera de empuje axial de la turbina de vapor. La causa principal de la falla es el desgaste y ensuciamiento severo de las etapas de la turbina que contribuye con un incremento de la carga axial de la turbina. Las consecuencias del deterioro de la turbina son: mayor carga axial debida al calentamiento adicional del rotor (requiere mayor vapor para generar la misma potencia que en condiciones de diseno); reduccion de la potencia motriz de la turbina y de la eficiencia isoentropica de las mismas, para un consumo de vapor promedio similar entre referencia y prueba. Debido a lo anterior la potencia de la turbina representa una desviacion del 34.74% en el Consumo Especifico de Vapor (CVE).

  19. Design and construction of a height caliper of labyrinths seals of high power steam turbines; Diseno y construccion de un calibrador de alturas para sellos laberintos de turbinas de vapor de alta potencia

    Energy Technology Data Exchange (ETDEWEB)

    Quinonez Osuna, Jose R. [Instituto Tecnologico de Mazatlan, Mazatlan, Sinaloa (Mexico); Mazur Czerwiec, Zdzislaw [instituto de Investigaciones Electicas, Cuernavaca, Morelos (Mexico); Valdez Valdez, Omar [Instituto Tecnologico de Mazatlan, Mazatlan, Sinaloa (Mexico)

    2007-11-15

    This article presents the development of a new instrument that allows calibrating with exactness the labyrinths seals height of the radial type, normally used in steam turbines and many other turbo-machines. The calibration process derived from the application of the designed instrument is distinguished from the existing one in the fact of considering a perpendicularity reference that allows high exactness in the measurement of height differences (0,008 mm), which is performed at the moment of adjusting the steam seals each time that its sheets are substituted for new ones. Such characteristic, allows therefore, higher efficiency conditions, stability and trustworthiness in the unit operation, once maintenance of this kind has been applied to it. The lack of monitoring and periodic maintenance of the gaps between seals and rotor constitutes the main cause of efficiency loss in power plant turbines installed in Mexico, generating wastes of up to 4% of its capacity, which represents 15 MW in high power units. [Spanish] El articulo representa el desarrollo de un nuevo instrumento que permite calibrar con exactitud las alturas de los sellos laberinticos de tipo radial, ordinariamente empleados en turbinas de vapor y en muchas otras turbo-maquinas. El proceso de calibracion derivado de la aplicacion del instrumento disenado se distingue del existente, en el hecho de considerar una referencia de perpendicularidad que permite alta precision en la medicion de diferencias de altura (0.008 mm.), lo cual es realizado en el momento de ajustar los sellos de vapor cada vez que sus laminas son sustituidas por nuevas. Dicha caracteristica, procura por ende condiciones mayores de eficiencia, estabilidad y confiabilidad en la operacion de la unidad, una vez que le ha sido brindado un mantenimiento de esta naturaleza. La falta de monitoreo y mantenimiento periodico de los claros entre sellos y rotor, constituye la principal causa de perdida de eficiencia en las turbinas de las

  20. Análisis de sensibilidad de las condiciones de frontera a la entrada del aspirador de la turbina 99

    Directory of Open Access Journals (Sweden)

    Sergio Galván

    2012-01-01

    Full Text Available Este trabajo se enfoca en establecer un estudio de la sensibilidad de los coeficientes que cuantifican el rendimiento del tubo de aspiración del Turbina 99 cuando las condiciones de frontera a la entrada son modificadas. Para esto, fue utilizado un método sistemático, objetivo y cualitativo llamad Diseño Factorial Fraccionado (Fractional Factorial Design que permite evaluar los efectos individuales y en conjunto de los parámetros del perfil de velocidades de entrada al aspirador sobre su rendimiento.Esta metodología fue aplicada a dos modelos numéricos que, resultado de un estudio de error de malla, se encuentran en los extremos de la curva asintótica de convergencia. Los resultados obtenidos con los modelos numéricos, después de modificar las condiciones de frontera, muestran que aunque exista una diferencia entre las cantidades que cuantifican el rendimiento del aspirador, estas presentan la misma tendencia y comportamiento. Además, el coeficiente de pérdida de energía mostró tener una mayor sensibilidad a los cambios de las condiciones de frontera, a diferencia del coeficiente de presión media comúnmenteutilizado como función objetivo en procesos de optimización.Así, un modelo numérico sometido a este estudio podría ser utilizado a un proceso que requiera una gran cantidad de simulaciones, como lo sería un proceso de optimización, sabiendo que dará resultados confiables y con un bajo costo computacional.

  1. Rehabilitation and extension of the useful operating life of a high pressure casing of the 75 MW steam turbine of the thermoelectric power plant President Juarez in Rosarito, B.C.; Rehabilitacion y extension de vida util de una carcasa de alta presion de la turbina de vapor de 75 MW de la central termoelectrica Presidente Juarez en Rosarito, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Mazur C, Zdzislaw; Hernandez R, Alejandro; Luna R, Alberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Fernandez, Rafael; Nieblas, Enrique [Comision Federal de Electricidad, Rosarito, Baja California (Mexico)

    2004-07-01

    The effective operation of the steam turbines is important to the world industries, but as all machinery, it is necessary to constantly examine and give maintenance to this equipment with the purpose of producing better results. Yet, many steam turbines arrive at an operation period of 30 or 40 years, over their original design capacity. A factor like this, only augments the probabilities of future problems with the casings, such as: thermal fatigue fissures, deformation of the horizontal union and erosion problems in the low pressure housings. The deformation of the casing can affect its capacity to maintain aligned the stationary parts of the turbine, as a consequence, damages can appear in the fixed and rotary components by interference or friction. Also, the water induction can deform the casing to such a degree that, the alignment of the stationary parts is altered until it causes contact and friction between stationary and rotary parts. However, depending on the type and degree of the casing deformation, different methods of rehabilitation can be applied. The core goal is to recover the planarity of the union of the flanges, re-machining the plane of the flange of the upper and lower casing or, alternatively, to carry out a scraping by hand. [Spanish] El funcionamiento eficaz de las turbinas de vapor es importante para las industrias del mundo, pero como toda maquinaria, es necesario examinar y dar mantenimiento constantemente a este equipo con la finalidad de producir mejores resultados. Con todo, muchas turbinas de vapor llegan a un periodo de operacion de 30 o 40 anos, por encima de su capacidad de diseno original. Un factor como este, solo eleva las probabilidades de futuros problemas con las carcasas, tales como: fisuras por fatiga termica, deformacion de la union horizontal y problemas de erosion en las carcasas de baja presion. La deformacion de la carcasa puede afectar su capacidad para mantener alineadas las partes estacionarias de la turbina, como

  2. Gas turbine application in power plants of Mexican refineries; Aplicacion de turbinas de gas en plantas de fuerza de refinerias mexicanas

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz Calderon, A. M.; Rodriguez Martinez, H.; Garcia Paredes, Job; Morales Guillen, Magdalena; Manzanares Papayanapolous, Emilio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: malcaraz@iie.org.mx; jhrm@iie.org.mx; jgarcia@iie.org.mx; mmmg@iie.org.mx; emp@iie.org.mx

    2010-11-15

    This article presents an overview of the application to have the gas turbine power generation systems, electric and steam for Mexican refineries. First there is a general description of the gas turbines and heat recovery (system components CHP) and CHP schemes are based on gas turbines capable of use in Mexican refineries. Subsequently referred to the characteristics of energy consumption (steam and electricity) from Mexican refineries and performs a technical analysis of CHP schemes based on gas turbines from the point of view of rates Q/W, power efficiencies and combined concluded that by their nature are very useful for refinery and gives some recommendations for improved implementation. [Spanish] En este articulo se presenta una vision general de la aplicacion que tienen las turbinas de gas en sistemas de generacion de energia electrica y vapor para refinerias mexicanas. Primeramente se da una descripcion general de las turbinas de gas y recuperadores de calor (componentes principales del sistema de cogeneracion) y se muestran los esquemas de cogeneracion basados en turbinas de gas susceptibles de utilizar en refinerias mexicanas. Posteriormente se mencionan las caracteristicas de consumos energeticos (vapor y energia electrica) de las refinerias mexicanas y se realiza un analisis tecnico de los esquemas de cogeneracion basado en turbinas de gas desde el punto de vista de tasas Q/W, eficiencias electricas y combinadas, concluyendose que por sus caracteristicas son muy utiles para refinerias y se dan algunas recomendaciones para su mejor aplicacion.

  3. Modelling and simulation of the steam line, the high and low pressure turbines and the pressure regulator for the SUN-RAH nucleo electric university simulator; Modelado y simulacion de la linea de vapor, las turbinas de alta y de baja presion y el regulador de presion para el simulador universitario de nucleo electricas SUN RAH

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, A. [DEPFI, Campus Morelos, en IMTA Jiutepec, Morelos, UNAM (Mexico)]. e-mail: andyskamx@yahoo.com.mx

    2003-07-01

    In the following article the development of a simulator that allows to represent the dynamics of the following systems: steam line, nozzle, vapor separator, reheater, high pressure turbine, low pressure turbine, power generator and the pressure regulator of a nucleo electric power station. We start from the supposition that this plant will be modeled from a nuclear reactor type BWR (Boiling Water Reactor), using models of reduced order that represent the more important dynamic variables of the physical processes that happen along the steam line until the one generator. To be able to carry out the simulation in real time the Mat lab mathematical modeling software is used, as well as the specific simulation tool Simulink. It is necessary to point out that the platform on which the one is executed the simulator is the Windows operating system, to allow the intuitive use that only this operating system offers. The above-mentioned obeys to that the objective of the simulator it is to help the user to understand some of the dynamic phenomena that are present in the systems of a nuclear plant, and to provide a tool of analysis and measurement of variables to predict the desirable behavior of the same ones. The model of a pressure controller for the steam lines, the high pressure turbine and the low pressure turbine is also presented that it will be the one in charge of regulating the demand of the system according to the characteristics and critic restrictions of safety and control, assigned according to those wanted parameters of performance of this system inside the nucleo electric plant. This simulator is totally well defined and it is part of the University student nucleo electric simulator with Boiling Water Reactor (SUN-RAH), an integral project and of greater capacity. (Author)

  4. Mantenimiento predictivo de turbinas de gas

    OpenAIRE

    Huertos Castellanos, Daniel

    2011-01-01

    Los motores de turbina de gas experimentan degradaciones con el tiempo que causan a sus usuarios gran preocupación sobre su fiabilidad y sus gastos de explotación. El diagnóstico del estado de una turbina de gas y la realización de pronósticos sobre su funcionamiento son tecnologías claves para poder pasar del uso de un tipo de mantenimiento previsto de forma fija a lo largo del tiempo (mantenimiento preventivo) a la utilización de un tipo de mantenimiento basado en las condiciones del funcio...

  5. Borosonic inspection and remaining useful operational life estimation of steam turbine rotors; Inspeccion borosonica y estimacion de vida remanente de rotores de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Carnero P, Jose A; Dorantes G, Oscar; Munoz Q, Rodolfo; Serrano R, Luis E. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    The turbo-generators used in the electric power generation frequently go through transitory operations (start ups, shut downs or power changes). Such actions cause that certain critical components of the turbines, such as rotors and casings, are put under cycles of repetitive stresses, which consume its useful life. The frequency whereupon these transitory thermal cycles happen result in the presence of high thermo-mechanical stresses that produce fatigue (damage) in the rotor material. With time, at the increase of the material fatigue, fissures form that can inclusively lead to severe, catastrophic faults. The borosonic inspection consists in introducing and positioning an automatic probe in the central drill of the rotor, this allows the non-destructive inspection with longitudinal ultrasonic beam, ultrasonic cross-sectional and ultrasonic superficial. This way, it is possible to detect and locate geometric discontinuities (superficial and volumetric), in at least 100 mm of depth from the drill surface in its entire periphery and throughout the rotor length. [Spanish] Los turbogeneradores empleados en la generacion de energia electrica con frecuencia realizan operaciones transitorias (arranques, paros o cambios de potencia). Acciones tales, provocan que ciertos componentes criticos de las turbinas, como los rotores y carcasas, sean sometidos a ciclos de esfuerzos repetitivos, lo que consume su vida util. La frecuencia con que ocurren estos ciclos termicos transitorios da como resultado la presencia de altos esfuerzos termomecanicos que producen una fatiga (dano) en el material del rotor. Con el tiempo, al incrementarse la fatiga del material, se forman fisuras que pueden conducir a fallas severas, catastroficas inclusive. La inspeccion borosonica consiste en introducir y posicionar una sonda automatica en el barreno central del rotor, ello permite la inspeccion no destructiva con haz ultrasonico longitudinal, haz ultrasonico transversal y haz ultrasonico

  6. Combined cycle simulator with gas turbine and steam turbine with one vaporization stage; Simulador de ciclo combinado con turbina de gas y de vapor con un nivel de vaporizacion

    Energy Technology Data Exchange (ETDEWEB)

    Del Valle Cardenas, B.; Lugo Leyte, R. [Universidad Autonoma Metropolitana, Depto de Ingenieria de Procesos e Hidraulica, Mexico, D. F. (Mexico); Toledo Velazquez, Miguel; Tolentino Eslava, G. [Seccion de Estudios de Posgrado e Investigacion, Laboratorio de Ingenieria Termica e Hidraulica Aplicada, ESIME-IPN-COFFA, Mexico, D. F. (Mexico)

    1998-12-31

    This paper shows the thermal analysis of a combined cycle with gas and steam turbines with one vaporization stage. The analysis is performed through a computer program, which allows the simulation of cycles with different operational conditions, obtaining this way a series of results that permits to know the way these cycles behave in effecting temperature and pressure changes; besides of being an excellent tool in thermodynamics for the user. The simulators were performed in Borland C++ and Builder C++ Versions 4.5 and 2.0 respectively, creating in this way a friendly ambient for the user. This tool offers the opportunity to all its users the ability to simulate combined cycles in a fast and easy way in order to obtain a wider understanding of its thermodynamic behavior. [Espanol] En el presente trabajo se muestra el analisis termico de un ciclo combinado con turbinas de gas y de vapor con un nivel de vaporizacion. El analisis se realiza a traves de un programa de computo, el cual permite simular los ciclos con diferentes condiciones de operacion, obteniendo con esto una serie de resultados que permiten conocer la forma en que trabajan estos ciclos al realizar cambios en temperaturas y presiones; ademas de que es una excelente herramienta para el usuario en termodinamica. Los simuladores fueron realizados en Borland C++ y Builder C++ Versiones 4.5 y 2.0 respectivamente, creandose asi un ambiente amigable para el usuario. Esta herramienta brinda la oportunidad a todos los usuarios de poder simular ciclos combinados de una manera rapida y sencilla con el fin de obtener una comprension mas amplia de su comportamiento termodinamico.

  7. Integration of a thermal stresses supervisory system and useful life of steam turbine rotors; Integracion de un sistema supervisorio de esfuerzos termicos y vida util de rotores de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Carnero, Antonio; Serrano, Luis E. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Nebradt, G. Jesus; Leyva, M. Luis [Comision Federal de Electricidad, Mexico, D.F. (Mexico)

    2007-11-15

    lado, la mayor eficiencia de centrales de ciclo combinado con respecto a centrales convencionales se refleja en un mayor costo de produccion de la energia electrica, lo que ha obligado a que unidades convencionales de generacion disenadas para operar con carga base, ahora sean utilizadas como unidades de carga variable para satisfacer la demanda durante las horas de mayor demanda. Lo anterior, repercute en una mayor frecuencia de operaciones de paros y arranques en calientes de turbinas, por lo que el dano por fatiga se incrementara al cambiar su regimen de operacion. En Mexico existen turbinas que llevan 15 o 20 anos en operacion y que no cuenta con un supervisor de esfuerzos termicos, por lo que al cambiar su operacion de carga base a carga variable es imprescindible instalar un supervisor de esfuerzos termicos del rotor, con el fin de limitar o reducir los esfuerzos termicos y con ello reducir el dano por fatiga para extender asi su vida util esencial. El articulo trata sobre la integracion de un sistema supervisor de esfuerzos termicos, que a partir de los parametros de operacion de la turbina, se determina el gradiente de temperaturas en la zona de sellos de laberinto entre el paso de control y el primer paso de la seccion del alta presion del rotor, se calculan los esfuerzos termicos y mecanicos y la fatiga, determinando el consumo de vida util por cada ciclo de operacion (paro y arranque).

  8. Diseño y construcción de un equipo de prueba y calibración, de tarjetas de control de turbinas de las unidades de generación de la Central Termoeléctrica "Santa Rosa", para la Empresa CELEC S.A. - Termopichincha

    OpenAIRE

    Proaño Cárdenas, Christian Iván; Sarango Sarango, Edwin Alexander; Chico Hidalgo, Patricio Iván; Burbano Villareal, Vladimir

    2012-01-01

    Actualmente, las calibraciones de las tarjetas que forman parte del sistema de control de turbina Speedtronic, en las unidades de generación de la Central Termoeléctrica Santa Rosa; se las realizan de forma complicada; debido a que, para llevar a cabo las mismas, los usuarios recurren a un equipo robusto que únicamente sirve de fuente de alimentación externa para las tarjetas; además, son necesarios documentos de procesos de mantenimiento anteriores y manuales de las máquina...

  9. Criteria for the provision and assembly of the rotor blades of a 300 MW low pressure steam turbine for electrical generation; Criterios para el suministro y ensambles de la alabes de rotor de turbina de vapor de 300 MW baja presion para generacion electrica

    Energy Technology Data Exchange (ETDEWEB)

    Bertin, Galo; Felix, Jorge A.; Quijano, Octavio [Especialistas en Turbopartes, S.A. de C.V., Queretaro, Queretaro (Mexico)

    2007-11-15

    This paper presents some of the main criteria to consider from the inspection, disassembling and assembly of blades with different root types of a turbine rotor of steam turbines for power generation, having as an aim to count on a reliable rotor, fulfilling with the equipment original design and norms and international standards. [Spanish] Este trabajo presenta algunos de los criterios principales a considerar desde la inspeccion, desmontaje y montaje de alabes de diferentes tipos de raiz de un rotor de turbinas de vapor de generacion electrica, teniendo como finalidad contar con un rotor confiable, cumpliendo con el diseno original del equipo y con normas y estandares internacionales.

  10. con turbinas de disco con paletas planas

    Directory of Open Access Journals (Sweden)

    D. García-Cortés

    2006-01-01

    Full Text Available Las turbinas de disco con paletas planas son los impelentes de flujo radial más ampliamente utilizados en la industria por constituir el impelente que forma parte de la configuración geométrica estándar para obtener este patrón de flujo en los tanques agitados. El estudio detallado de la hidrodinámica en este sistema de agitación es fundamental para continuar obteniendo conocimientos básicos imprescindibles para la síntesis y la modelación matemática de diferentes procesos complejos que se llevan a cabo en los tanques agitados, por ejemplo, la cristalización esférica. El propósito de este artículo es hacer una revisión de la información publicada sobre la hidrodinámica y la modelación matemática de la dinámica de fluidos en los tanques agitados con turbinas de disco con paletas planas y señalar los avances logrados en cada uno de los aspectos abordados y aquellos en los cuales es necesario seguir investigando.

  11. Análise termodinâmica de um ciclo de potência com célula a combustível sofc e turbina a vapor = Thermodynamic analysis of a power cycle such as SOFC fuel cell and steam turbine

    Directory of Open Access Journals (Sweden)

    Alexandre Sordi

    2006-01-01

    Full Text Available O objetivo deste artigo foi realizar a análise termodinâmica de um sistema híbrido, SOFC / ST (célula a combustível tipo SOFC e turbina a vapor ST. O combustível considerado para a análise foi o gás metano (biogás produzido por meio da digestão anaeróbica de resíduos orgânicos. A metodologia utilizada foi o balanço de energia dosistema SOFC / ST, considerando a reforma interna do metano na célula a combustível, de forma a obter a sua eficiência elétrica. O resultado foi comparado a um ciclo combinado convencional de turbina a gás e turbina a vapor (GT / ST para potências entre 10 MW e 30MW. A eficiência do sistema híbrido SOFC / ST variou de 61% a 66% em relação ao poder calorífico do metano; e a eficiência do ciclo combinado GT / ST variou de 41% a 55% para o mesmo intervalo de potência. Para geração distribuída a célula a combustível SOFC é atecnologia mais eficiente.The objective of this article was to analyze the thermodynamic of ahybrid system, SOFC / ST (SOFC fuel cell and ST steam turbine. The fuel for the analysis was the gas methane (biogas produced through the anaerobic digestion of the organic residues. The utilized methodology was the energy balance of the system SOFC / ST,considering the internal reforming of methane in the fuel cell, in a way to obtain its electric effectiveness. The result was compared to a conventional combined cycle of gas turbine and steam turbine (GT / ST for powers between 10 MW and 30 MW. The efficiency of the hybrid system SOFC / ST varied from 61 to 66% in relation to the lower heating value of methane; and the efficiency of the combined cycle GT / ST varied from 41 to 55% within the same power interval. For distributed generation, the SOFC fuel cell is the most efficienttechnology.

  12. Performance optimization methodology in a Francis turbine vacuum cleaner based on the modification of the boundary conditions; Metodologia de optimizacion del rendimiento en un aspirador de turbina Francis en base a la modificacion de las condiciones de frontera

    Energy Technology Data Exchange (ETDEWEB)

    Galvan Gonzalez, S.; Rubio Maya, C.; Mendoza Covarrubias, C. [Universidad Michoacana de San Nicolas Hidalgo, Morelia, Michoacan (Mexico)]. E-mail: srgalvan@umich.mx; crmaya@umich.mx; cmendoza@umich.mx; Pacheco Ibarra, J.; Martinez Patino, J. [Universidad de Guanajuato, Salamanca, Guanajuato (Mexico)

    2010-11-15

    This paper focus on establishing an optimization methodology for maximizing the draft tube performance as a function of the inlet velocity profile. The overall work is defined by four steps: the inlet velocity profile parametrization, the numerical optimization set-up, the numerical computational fluid dynamics (CFD) draft tube model and the objective function definition. However as the inlet velocity profile is a new challenge, each step of the parametrization must be properly validated. In the first step, a suitable parametrization with an appropriate number of variables is chosen to approximate an experimental draft tube inlet velocity profile. The second step considers the reduction of the actual numerical model to develop the CFD calculations. In the third step, the optimization algorithm set-up is specified. Finally, the objective function is evaluated. As each step is properly validated, it is considered this proved methodology will help to find an inlet velocity profile shape which will be able to suppress or mitigate the undesirable draft tube flow characteristics. [Spanish] Este documento se enfoca en establecer una metodologia de optimizacion para maximizar el rendimiento del tubo de aspiracion en funcion de las condiciones de frontera del aspirador. El metodo es definido en cuatro etapas: la parametrizacion del perfil de velocidades, la evaluacion del algoritmo de optimizacion, la valoracion de la funcion objetivo y la validacion del modelo numerico. La parametrizacion se realiza con un numero de variables apropiado para aproximar el perfil de velocidades experimental. El segundo paso considera establecer los parametros del algoritmo de optimizacion, la funcion objetivo es obtenida mediante un estudio de sensibilidad y el modelo numerico es validado y reducido en la cantidad de elementos para adecuarlo al proceso de optimizacion. Se considera que esta metodologia ayudara a encontrar un perfil de velocidad de entrada el cual reduzca las perdidas de

  13. Effect on the performance with the washing of the gas turbines Ruston TB5000 with a system of washing out of line in high contamination conditions; Efecto en el rendimiento con el lavado de las turbinas de gas Ruston TB5000 con un sistema de lavado fuera de linea en condiciones de alta contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Diaz, Carlos Rodolfo; Aboites Davila, Fernando [CIATEQ, A.C., Queretaro (Mexico); Rocha Orozco, Moises [PEMEX Refinacion, Mexico, D.F. (Mexico)

    2007-11-15

    This paper shows the effects on the gas turbine performance with a washing system out of line, based on liquid detergent and water for the case of 2 Ruston TB5000 gas turbines located in conditions of high contamination in the atmosphere such as ashes, high humidity and temperature. The investigation was realized making periodical measurements of the main parameters of the turbo-pump during 1 year of operation with load conditions without stopping of about 125 mbpd (million of barrels per day) of gas LP. This article suggests how the low performance of the turbines in a hostile atmosphere can be improved and which could be the limitations of the washing systems based on liquid detergents. The data of the washing sessions were collected during a year and studied under statistical methods creating performance curves and comparing them with curves of other machines being washed with other washing systems. [Spanish] Este trabajo muestra los efectos en el rendimiento de la turbina de gas con un sistema de lavado fuera de linea, basado en detergente liquido y agua para el caso de 2 turbinas de gas Ruston TB5000 localizados en condiciones de alta contaminacion en el ambiente como cenizas, alta humedad y temperatura. La investigacion fue realizada haciendo mediciones periodicas de los parametros principales de turbo bomba durante 1 ano de operacion con condiciones de carga sin parar de alrededor de 125 mbpd (millones de barriles por dia) de gas LP. Este articulo sugiere como se puede mejorar el bajo desempeno de las turbinas en un ambiente hostil y cuales podrian ser las limitaciones de los sistemas de lavado basados en detergentes liquidos. Los datos de las sesiones de lavado fueron recolectados durante un ano y estudiados bajo metodos estadisticos creando curvas de rendimiento y comparandolas con curvas de otras maquinas siendo lavadas con otros sistemas de lavado.

  14. Code for the steam tables for pure water in visual basic 6.0.; Un codigo para las tablas de vapor para agua pura en visual basic 6.0

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Mahendra P. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2002-07-01

    The thermodynamic data of the water are of extreme importance in all of the branches of science and technology; the facilitate the understanding of the natural Earth processes. Nevertheless, for the electrical industry the water plays a very important role during the generation of electrical energy process. Different heat sources such as coal, oil, natural gas, nuclear fuel or the geothermal heat boil the water that forms the steam used to move the turbines. Consequently, the steam tables (the thermodynamic water data) are vital to model thermal and mass transference and physical-chemical processes during the generation of electrical energy. [Spanish] Los datos termodinamicos del agua son de suma importancia en todas las ramas de la ciencia y tecnologia, ellos facilitan el entendimiento de los procesos naturales de la Tierra. Sin embargo, para la industria electrica el agua juega un papel muy importante durante el proceso de generacion de energia electrica. Diferentes fuentes de calor tales como carbon, aceite, gas natural, combustible nuclear o el calor geotermico calientan el agua que forma el vapor utilizado para mover las turbinas. Luego entonces, las tablas de vapor (los datos termodinamicos de agua) son vitales para modelar transferencia termica y de masa y procesos fisico-quimico durante la generacion energia electrica.

  15. Medidas para el incremento de la eficiencia energética en una turbina

    OpenAIRE

    Martínez Pérez, Francisco; Pérez Paz, Yoismel

    2009-01-01

    El presente trabajo realizado en una central termoeléctrica da a conocer un conjunto de recomendaciones, basadas en el análisis tribológico, para incrementar el diagnostico y mejorar la eficiencia a través del análisis del sistema de análisis del lubricante en una turbina generadora de electricidad. En el desarrollo del trabajo se llevaron a cabo herramientas importantes como el análisis de criticidad de la turbina, las recomendaciones para la toma de muestras de lubricantes, en estos...

  16. Cooling system at the compressors air inlet of the gas turbines from the Tula`s combined cycle central; Sistema de enfriamiento en la succion del compresor de las turbinas de gas de la central de ciclo combinado de Tula

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez F, Oscar [Comision Federal de Electricidad, Tula (Mexico); Romero Paredes, Hernando; Vargas, Martin; Gomez, Jose Francisco [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico)

    1996-12-31

    It has been formerly evaluated that it is possible to enhance notably the electric power generation in gas turbine power plants by cooling the air at the compressor inlet. It has been pointed out that provided a source of waste heat is available it can be very attractive the use of absorption refrigeration systems. In this paper the technical and the economical benefits of bringing the air inlet temperature down 8 Celsius degrees of the four gas turbines of the Combined Cycle Central of Tula, in the State of Hidalgo (combined cycle central-Tula) are evaluated. The results show that it is possible to achieve an efficiency enhancement of at least 1%, and that in very warm days up to 48 additional Megawatts can be generated, or about 10% of the installed capacity. The final economic result is very encouraging and an annual economical benefit in the order of 50 million pesos can be obtained and the refrigeration units can be amortized in approximately one year. [Espanol] Se ha evaluado anteriormente que es posible mejorar notablemente la capacidad de generacion electrica en plantas que utilizan turbinas de gas, mediante el enfriamiento del aire de succion del compresor. Se ha senalado que en la medida en que se encuentre disponible una fuente termica de desecho puede ser muy atractivo el uso de sistemas de refrigeracion por absorcion. En el presente trabajo se evaluan los beneficios tecnicos y economicos que puede tener el llevar el aire de succion hasta una temperatura de 8 grados Celsius, de las cuatro unidades de gas de la Central de Ciclo Combinado de Tula, Hidalgo (CCC-Tula). Los resultados muestran que es posible alcanzar un aumento en la eficiencia de al menos 1% y que se pueden generar, en dias muy calurosos, hasta 48 MW extras, equivalente al 10% de la capacidad instalada. El resultado economico final es muy alentador y puede llegar a tenerse un beneficio economico del orden de los 50 millones de pesos anuales y las unidades de refrigeracion podran pagarse en

  17. Estimation of consumption of the useful life in the nozzles of a gas turbine by the phenomenon of thermal fatigue; Estimacion de consumo de vida util en las toberas de una turbina de gas por el fenomeno de fatiga termica

    Energy Technology Data Exchange (ETDEWEB)

    Perez Hernandez, Efrain [Centro Nacional de Investigacion y Desarrollo Tecnologico (Cenidet), Cuernavaca, Morelos (Mexico); Mazur C, Zdzislaw; Garcia Illescas, R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    damage. [Spanish] La estimacion de vida util en los componentes calientes de las turbinas de gas como toberas y alabes es importante ya que sufren de cambios criticos de temperatura los cuales producen fatiga termomecanica durante los arranques, paros y cambios de fatiga para estimacion de vida util en las toberas de turbina de gas fabricados de aleacion base cobalto FSX-414 en las cuales se han desarrollado grietas durante la operacion. La inspeccion visual y metalografia de la tobera revelo muchas grietas por fatiga termomecanica en la superficie del alabe ademas de deterioracion de la aleacion. En los limites de grano se encontro una pelicula continua de carburos y tambien aumento de fraccion de carburos dentro de los granos. Esta densa y continua red de carburos reduce la ductilidad y aumenta la fragilidad, junto con la reduccion de energia de impacto (Charpy), facilita la iniciacion y propagacion de grietas. La iniciacion y propagacion de grieta en la aleacion fue debido a un mecanismo de fatiga termica y termofluencia que fue facilitado por fragilidad del material debido al deterioro previamente mencionado y a significativos niveles de esfuerzos termomecanicos. En el presente articulo se presentan los resultados de analisis de esfuerzos termicos a partir de los resultados de temperatura obtenidas de estudios previos de un analisis de transferencia de calor y flujo de fluidos mediante el programa Star-CD basado en volumen finito. Se muestra la metodologia empleada y las distribuciones de esfuerzos, los cuales se emplearon para el analisis de fatiga para la estimacion de vida util. Para eso se utilizo un modelo de elementos finitos en el programa NISA, asi como el programa de analisis de fatiga nCode. Para el conteo de ciclo de utilizo el metodo de Rainflow y se compararon los modelos de vida por fatiga de Manson-Coffin, Basquin, Morrow y Smih-Watson-Topper. La variacion de las propiedades mecanicas con la temperatura de la superaleacion empleada en esos componentes

  18. Classification of the operating conditions of a Kaplan turbine according to its impact in the structural integrity of the runner; Clasificacion de las condiciones de operacion de una turbina Kaplan de acuerdo a su impacto en la integridad estructural del rodete

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, Luis M.; Bautista, Eder A.; Espitia, J. Ernesto [Instituto Tecnologico de Pachuca, Pachuca, Hidalgo (Mexico); Mazur C, Zdzislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    Each one of the operating conditions of the turbine according to the impact they have in the structural integrity of the runner is evaluated. By means of CFD (Computational Fluid Dynamics) analysis the pressure that the working fluid exerts on the blade for the turbine operating conditions is obtained. The oscillating disturbances induced by the flow, the angular velocity of the runner and the cavitation effect have been considered. The value of maximum stress for each one of the operating conditions is related to its respective values of cavitation. With this information those operating conditions that induce the greater values of stress and represent greater wears away in the runner are determined. This way, it is possible to avoid the more severe operating conditions and if this is not possible, lineaments of redesign are established to obtain more favorable operating conditions for the runner. [Spanish] Se evaluan y clasifican cada una de las condiciones de operacion de la turbina de acuerdo al impacto que tienen en la integridad estructural del rodete. Mediante analisis de CFD (Computacional Fluid Dynamics) se obtiene la presion que el fluido de trabajo ejerce sobre el alabe para las condiciones de operacion de la turbina. Se han considerado las perturbaciones oscilatorias inducidas por el flujo, la velocidad angular del rodete y el efecto de la cavitacion. Se relacionan los valores de esfuerzo maximo para cada una de las condiciones de operacion con sus respectivos valores de cavitacion. Con esta informacion se determinan aquellas condiciones de operacion que inducen los mayores valores de esfuerzo y representan mayor desgaste en el rodete. De esta manera, es posible evitar las condiciones de operacion mas severas, y si esto no es posible, se establecen lineamientos de rediseno para obtener condiciones de operacion mas favorables para el rodete.

  19. Detection of the high vibration origin in the body of an electrical generator driven by steam turbine applying diagnostic techniques; Deteccion del origen de alta vibracion en el cuerpo de un generador electrico accionado por turbinas de vapor aplicando tecnicas de diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Bravo, Fernando (Mexico)

    2007-11-15

    One of the problems that electric generators present is the high vibration due to causes that can go from simple mechanical unbalance, misalignment, mechanical relaxation, resonance or some other interaction that can influence in the system. In this document is presented the vibration analysis of an electric generator with a capacity of 350 MW, driven by a steam turbine composed of three stages (high pressure, intermediate pressure and low pressure) connected to the electric generator through a rigid connection. [Spanish] Uno de los problemas que se presentan en los generadores electricos es la alta vibracion debida a causas que pueden ir desde un simple desbalance mecanico, desalineamiento, aflojamiento mecanico, resonancia o alguna otra interaccion que pueda influir en el sistema. Se presenta en este documento el analisis de vibracion de un generador electrico con una capacidad de 350 MW, impulsado por una turbina de vapor compuesta de tres etapas (alta presion, presion intermedia y baja presion) acopladas al generador electrico a traves de un acoplamiento rigido.

  20. Study of the state of the art of the technologies for the extension of the useful life of the gas turbine buckets; Estudio del estado del arte de las tecnologias de extension de la vida util de los alabes de turbina de gas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Gutierrez, Ramiro Arturo

    1995-10-01

    In the present work a revision of the state of the art of the technologies involved in the extension of useful life of the buckets of a gas turbine is made. Among the subjects that are presented, stand out the following ones: materials for the manufacture of blades; processes of blade manufacturing; Wearing down of blades after a prolonged service; evaluation methods for blades; Limits of repair for blades rehabilitated by welding and strong welding; cleaning of blades; recovery heat treatments; Isostatic compression in hot; Welding of blades; electrical laser beam machining; coating for blades; shotpeening of the blades; balance of blades. In addition as a contribution of the present work, the development of a flow chart for the repair of buckets of gas turbines that exhibit the following typical wearing downs: corrosion, oxidation, erosion, frictions, impact and thermofluency. It is also included as a contribution, a proposal of rehabilitation for the extension of the useful life of the first stage blades of the 3 gas turbines Asea Brown Boveri (ABB) model 11 D-5 MCA, 61.2 MW that operate in the combined cycle thermoelectric power station El Sauz located in the state of Queretaro, Mexico. [Espanol] En el presente trabajo se realiza una revision del estado del arte de las tecnologias involucradas en la extension de vida util de los alabes de turbina de gas. Entre los temas que se presentan destacan los siguientes: materiales para la fabricacion de alabes; procesos de fabricacion de alabes; desgaste en alabes despues de un servicio prolongado; Metodos de evaluacion para alabes; limites de reparacion para alabes rehabilitados por soldadura y soldadura fuerte; limpieza de alabes; tratamientos termicos de recuperacion; Compresion isostatica en caliente; soldadura de alabes; maquinados electricos y con rayo laser; Recubrimientos para alabes; granallado de alabes; balance de alabes. Ademas se presenta como aportacion del presente trabajo, el desarrollo de un diagrama de

  1. Emulador de Lazo Abierto para Turbinas Eólicas de Paso Fijo Open Loop Emulator for Fixed Pitch Wind Turbines

    OpenAIRE

    Fernando Martínez; Santiago de Pablo; Luis C Herrero

    2011-01-01

    Se presenta un nuevo emulador para turbinas eólicas de paso fijo, que permite realizar pruebas de laboratorio de los sistemas de control de los generadores asociados a las turbinas eólicas. La novedad del emulador consiste en utilizar un esquema en lazo abierto. El emulador consiste en el acoplamiento en serie de los siguientes elementos: una fuente de tensión de CC, una resistencia de potencia y un motor de CC. La modificación de la tensión en CC tiene el mismo efecto que la variación de la ...

  2. Vapor recovery system in the gasolines commercialization; Sistema de recuperacion de vapores en la comercializacion de las gasolinas

    Energy Technology Data Exchange (ETDEWEB)

    Casas Barba, R.; Molina Gallegos, J.R. [Instituto Mexicano del Petroleo (IMP), Mexico, D. F. (Mexico)

    1995-12-31

    In the last years the studies performed with respect to the environmental pollution show that the ozone is one of the most problematic contaminants in the Metropolitan Zone of Mexico City (MZMC) and that the hydrocarbons are the main forerunners of it. The main source of hydrocarbon vapor emissions originates from the handling and distribution operations. In this paper a description is made of the involved stages in the commercialization of gasolines in the MZMC and a description is also made of the systems employed to control the emissions in the three stages of the fuels storage and distribution cycle and explains the degree the hydrocarbon emissions to the atmosphere will be reduced, once the recovery systems are installed in all of the involved stages. [Espanol] En los ultimos anos los estudios realizados con respecto a contaminacion ambiental reflejan que el ozono es uno de los contaminantes mas problematicos de la zona metropolitana de la ciudad de Mexico (ZMCM), y los hidrocarburos son los principales precursores de este. La principal fuente de emision de vapores de hidrocarburos proviene de las operaciones de manejo y distribucion de combustibles. En este articulo se hace una descripcion de las etapas involucradas en la comercializacion de las gasolinas en la ZMCM, se describen tambien los sistemas utilizados para controlar las emisiones en las tres etapas del ciclo de almacenamiento y distribucion de combustibles y se explica en que grado se reduciran las emisiones de hidrocarburos a la atmosfera, una vez que se instalen los sistemas de recuperacion en todas las etapas involucradas.

  3. Máquina turborrefrigeradora para el enfriamiento de una turbina de un turbofan de altas temperaturas

    OpenAIRE

    Huamán Pérez, Fernando; Huamán Pérez, Fernando

    1998-01-01

    El trabajo consiste en analizar el funcionamiento de tres configuraciones de los turbo refrigeradores, evaluar su algoritmo de cálculo, y mediante un programa obtener las curvas de variación, de la temperatura del aire de enfriamiento que ingresa a la turbina de alta. De las tres configuraciones analizadas, escoger una y obtener sus nuevos parámetros usando como datos iniciales los parámetros de un avión de última generación, también analizamos las curvas de temperatura, empuje, relación de c...

  4. Continuidad de suministro de turbinas eólicas de velocidad fija

    OpenAIRE

    Ríos Villacorta, Alberto; Arnaltes Gómez, Santiago; Rodríguez Amenedo, José Luis

    2009-01-01

    En este artículo se evalúa la capacidad de los aerogeneradores de velocidad fija de mantener la continuidad de suministro ante huecos de tensión bifásicos y trifásicos en función del disparo de las protecciones del aerogenerador asíncrono de velocidad fija y de las limitaciones de consumo de energía y potencia (activa y reactiva) durante la duración del hueco de tensión. El objetivo de estos estudios es comprobar la capacidad de las turbinas eólicas de velocidad fija en el cumplimiento de los...

  5. Analysis of the consumption of useful life by thermal fatigue in the gas turbine nozzles during the operation at continuous load and transients; Analisis de consumo de vida por fatiga termica en las toberas de turbina de gas durante operacion con carga continua y transitorios

    Energy Technology Data Exchange (ETDEWEB)

    Perez Hernandez, Efrain Betuel

    2007-08-15

    The gas turbines operate at extremely high temperatures, with high thermal and mechanical stresses, causing that the life of the involved components diminishes. In the present thesis the temperature distribution on the nozzle obtained in other investigation as a result of heat transfer and fluid flow analysis applying CDF code Star-CD was used. Next, the program NISA was used to perform the analysis of thermal stresses by means of finite element method. Finally, the results of stress analysis were introduced to the program nCode to accomplish the nozzle remaining useful life assessment due to thermal fatigue in critical location on the nozzle by means of the CLF module (Critical Location Fatigue). The full methodology used to determine the nozzle operational conditions, load history, material properties and the fatigue model used to determine the number of cycles to failure of the nozzle during constant load and transients operation is presented. [Spanish] Las turbinas de gas operan a temperaturas extremadamente altas, a elevados esfuerzos termicos y mecanicos, ocasionando que la vida de los componentes involucrados se reduzca. En la presente tesis se presentan los resultados realizados por otras investigaciones de temperaturas obtenidas a partir de un analisis de transferencia de calor y flujo de fluidos de la tobera mediante el programa Star-CD basado en volumenes finitos. Posteriormente, se utilizo el programa NISA para realizar el analisis de esfuerzos mediante elementos finitos. Finalmente, se llevaron los resultados al programa nCode para realizar la estimacion de vida util por fatiga termica en un punto critico de la tobera mediante el modulo CLF (Critical Location Fatigue). Se muestra la metodologia empleada para determinar las condiciones de operacion, historial de carga, propiedades del material y el modelo de dano por fatiga para determinar el numero de ciclo para falla de la tobera durante operacion con carga continua y transitorios.

  6. Estudio comparativo del comportamiento vibratorio de un conjunto de turbinas eólicas

    OpenAIRE

    Oriol Asensio, Daniel

    2011-01-01

    El proyecto “Estudio comparativo del comportamiento vibratorio de un conjunto de turbinas eólicas” pretende, en las hojas que siguen, determinar patrones de respuesta vibratoria en diferentes posiciones de la cadena de transmisión de potencia. El interés de dicho estudio reside en la mejora de los sistemas de mantenimiento predictivo basados en vibraciones. De esta forma se podrá aumentar la fiabilidad y eficiencia de estas máquinas generadoras de energía eléctrica a partir de ...

  7. The aggressiveness of the geothermal steam controlled; La agresividad del vapor geotermico controlada

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, Sergio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    The first two units of Cerro Prieto have generated electric energy since 1973; in 1988 completed 15 years of continuous operation, without corrosion problems in the turbines in spite of the utilization of geothermal steam. The experience and the good results obtained during the first years of operation of these two units of 37.5 MW each, were of great help for the Cerro Prieto extension, having as of this date an installed capacity of 620 MW. [Espanol] Las dos primeras unidades de Cerro Prieto han generado energia electrica desde 1973; cumplieron 15 anos de operacion continua en 1988, sin problemas de corrosion en las turbinas a pesar del uso de vapor geotermico. La experiencia y los buenos resultados obtenidos durante los primeros anos de operacion de estas dos unidades de 37.5 MW cada una fueron de gran apoyo para la aplicacion de Cerro Prieto, teniendose a la fecha 620 MW de capacidad instalada.

  8. Memoria de la reparación de los cojinetes de la turbina propulsora del b.a.e. Rafael morán valverde

    OpenAIRE

    Muñoz Martinez, Jorge; Wiesner Falconi, Ignacio

    2009-01-01

    MEMORIA DE LA REPARACIÓN En Septiembre de 1998 se recibieron en las oficinas de INTRAMET cojinetes de deslizamiento pertenecientes al B.A.E. Rafael Morán Valverde los mismos que son piezas de las turbinas del sistema de propulsión, cuyas características son las siguientes: º MARCA: J.S. WHITE English Electric Design º TIPO: MARK Y 136 de 8 Etapas. º POTENCIA: 15000 HP º VELOCIDAD MAXIMA: 5750 r.p.m. º VELOCIDAD CRITICA: 7320 r.p.m. En mayo de 1.998 los dos cojin...

  9. Analysis of the fault and malfunctioning of a 15 MW hydraulic turbine; Analisis de la falla y malfuncionamiento de una turbina hidraulica de 15 MW

    Energy Technology Data Exchange (ETDEWEB)

    Garcia I, Rafael; Perez R, Norberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-07-01

    An historical case of the rehabilitation process of three hydraulic turbines with capacity of 15 MW each is presented. These units are used for the electrical generation, mainly to supply part of the central zone of the Mexican Republic. The turbo-generator units had been practically destroyed by catastrophic floods and only part of the equipment was rescued and rehabilitated for its operation. One of the three turbines presented serious operational problems, preventing its reliable operation evidenced by the excessive mechanical vibrations and heating of the bearing zone. This article presents the diagnosis of the possible causes of fault and the remedial actions taken. Strong misalignment problems of the runner with respect to its bearings and to the scroll case of the turbine are observed. In addition, during the inspection of the turbine runner and of the bearings it is observed that important frictions have existed, which increased the vibrations. It is shown that these frictions are not the cause of the problem but only one manifestation of the same. Finally some conclusions of the problem and their solution are presented. [Spanish] Se presenta un caso historico del proceso de rehabilitacion de tres turbinas hidraulicas con capacidad de 15 MW cada una. Dichas unidades son empleadas en la generacion electrica, principalmente para abastecer parte de la zona centro de la Republica Mexicana. Las unidades turbogeneradores habian sido practicamente destruidas por inundaciones catastroficas y solo parte del equipo fue rescatado y rehabilitado para su operacion. Una de las tres turbinas presento graves problemas de funcionamiento, impidiendo su operacion confiable, lo cual se manifestaba mediante vibraciones mecanicas excesivas y calentamiento en zona de chumaceras. En este articulo se presenta el diagnostico de las posibles causas de falla y las acciones correctivas tomadas. Se observan problemas fuertes de desalineamiento del rotor respecto a sus chumaceras y al

  10. Analysis of the malfunctioning and failure of a 15 MW hydraulic turbine; Analisis de malfuncionamiento y de falla de una turbina hidraulica de 15 MW

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Illescas, R.; Perez Rodriguez, N. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    A case history is presented of the rehabilitation process of three hydraulic turbines with a capacity of 15 MW each one. Such units are used for electric power generation, mainly to supply part of the center zone of the Mexican Republic. The turbo-generator units had been practically destroyed by catastrophic floods and only part of the equipment was recovered and reconditioned for its operation. One of the three turbines presented serious functioning problems preventing its reliable operation that was evidenced by excessive mechanical vibrations and heating in the bearing zone. This paper presents the diagnosis of the possible causes of failure and the corrective measures taken. Serious rotor misalignment problems were observed respect to its bearings and the turbine scroll. Additionally, during the inspection of the turbine runner and of the bearing it was observed that important friction have existed, which incremented the vibrations. It is shown that such rubbings are not the cause of the problem but only a manifestation of the same. Finally some of the conclusions and their solution are presented. [Spanish] Se presenta un caso historico del proceso de rehabilitacion de tres turbinas hidraulicas con capacidad de 15 MW cada una. Dichas unidades son empleadas en la generacion electrica, principalmente para abastecer parte de la zona centro de la republica mexicana. Las unidades turbogeneradores habian sido practicamente destruidas por inundaciones catastroficas y solo parte del equipo fue rescatado y rehabilitado para su operacion. Una de las tres turbinas presento graves problemas de funcionamiento, impidiendo su operacion confiable, lo cual se manifestaba mediante vibraciones mecanicas excesivas y calentamiento en zona de chumaceras. En este articulo se presenta el diagnostico de las posibles causas de falla y las acciones correctivas tomandas. Se observan problemas fuertes de desalineamiento del rotor respecto a sus chumaceras y al caracol de la turbina

  11. Recubrimientos contra la corrosión a alta temperatura para componentes de turbinas de gas

    Directory of Open Access Journals (Sweden)

    Agüero, A.

    2007-10-01

    Full Text Available Hot section gas turbine components are made of superalloys, developed to withstand high temperatures in conditions in which mechanical stresses are high and that require high surface stability. However, during the 50s it became evident that compositions resulting in high mechanical strength for these materials were not compatible with those offering optimal protection from the working environments. The idea of employing protective coatings over materials with high mechanical strength resulted therefore from this situation. Presently, both aeronautic and power generation turbines operate at temperatures within the 900-1400 °C, thanks to these coatings, indispensable for their correct operation. In this work, the principal degradation mechanisms in these operating conditions and the different type of coatings presently employed by the industrial sector are described, beginning by the oldest Ni or Co aluminides, following with the addition of other metals such as Pt, Cr, etc. to the former coatings in order to increase their useful life, continuing with the overlay MCrAlY coatings and finishing with the thermal barrier coating systems. Moreover, the corresponding deposition techniques industrially employed to deposit these coatings are described, and finally, an insight of the latest research lines currently being developed is also included.

    Los componentes de las zonas calientes de las turbinas de gas están hechos de superaleaciones desarrolladas para soportar altas temperaturas, en condiciones en que las tensiones mecánicas son relativamente altas y en las que se requiere una alta estabilidad superficial. Sin embargo, durante la década de 1950-60, se hizo evidente que las composiciones que aumentaban la resistencia mecánica de estos materiales y aquellas que ofrecían una óptima protección contra ambientes agresivos no eran compatibles. Esto, condujo a la idea de emplear recubrimientos protectores sobre materiales con alta

  12. Metalurgia de alabes móviles con banda integrada de turbinas de gas y su influencia sobre el comportamiento de los alabes

    Directory of Open Access Journals (Sweden)

    Mazur, Z.

    1999-02-01

    Full Text Available The influence of the microstructure of the gas turbine blades with integral shroud on the blades performance is presented. The analysis of the solidification process of the gas turbine blades during conventionally casting process (equiaxed grains with all elements which has influence on the mode of its solidification and variation of the microstructure is carried out. Also, the evaluation of the failure of the gas turbine blade is presented. A detailed analysis of the blade tip shroud microstructure (presence of the equiaxed and columnar grains and its influence on the failure initiation and propagation is carried out. Finally, conclusions and some necessary improvements of the blades casting process to prevent blades failures are presented.

    Se presenta la influencia de la microestructura en el comportamiento de los alabes móviles con banda integrada de turbinas de gas bajo condiciones reales de trabajo. Para el proceso de vaciado convencional (granos equiaxiales de los alabes de turbinas de gas se lleva a cabo el análisis del proceso de solidificación presentando todos los elementos que influyen al modo de solidificación de un alabe y en la variación de la microestructura resultante. Se hace la evaluación de la falla de un alabe con la banda integrada de turbina de gas presentando el mecanismo de la falla y la influencia de la microestructura de la banda del alabe al inicio y propagación de la falla. Finalmente, se presentan las conclusiones determinando los elementos principales de la microestructura que influyen en el comportamiento de los alabes y las medidas preventivas para adecuar la microestructura a las condiciones de trabajo de los alabes.

  13. Fundaciones para turbinas eólicas costa afuera Foundations for offshore wind turbines

    Directory of Open Access Journals (Sweden)

    Felipe Alberto Villalobos Jara

    2009-01-01

    Full Text Available Este artículo describe el comienzo y la evolución de la hoy en día creciente mundialmente industria de la energía eólica costa afuera. Como un caso particular, se describe la actual política de energías renovables en el Reino Unido. Se explican las características de las cargas ambientales existentes costa afuera, tipos de suelos del fondo marino y las fundaciones que se utilizan comúnmente. El tipo de estructura y régimen de carga establecen nuevas condiciones desde el punto de vista de la Ingeniería Civil. Se presentan las cámaras a succión como una fundación alternativa para turbinas de viento costa afuera. Las cámaras a succión son actualmente una alternativa aceptada en vez de usar pilotes en aplicaciones para la industria del petróleo y el gas. Sin embargo, este no es el caso todavía en aplicaciones para aerogeneradores costa afuera.This paper describes the beginning and evolution of the now worldwide growing offshore wind energy industry. In particular, the current renewable energy policy in the UK is described. The characteristics of the environmental loads offshore, type of seabed soils and foundations commonly adopted are explained. The type of structure and loading regime establish new conditions from a Civil Engineering point of view. Suction caissons are introduced as an alternative foundation for offshore wind turbines. Suction caissons are currently an accepted alternative to pile foundations in applications for the oil and gas industry. However, this is not yet the case in applications for offshore wind turbines.

  14. Boiler model of a 300 Mw fossil fuel power plant for the turbine turning simulator; Modelo de caldera de una planta termoelectrica de 300 Mw para el simulador de rodado de turbina

    Energy Technology Data Exchange (ETDEWEB)

    Rossano Roman, Miguel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-07-01

    ). En este articulo se describen las ecuaciones del modelo para una caldera de una planta termica de 300 Mw, basadas en balances y relaciones fisicas. Se muestran las consideraciones y simplificaciones basicas. El modelo considera la combustion en el hogar, el domo, la tuberia de bajada, las bombas de recirculacion, las paredes de agua, el sobrecalentador y el recalentador. Los balances de materia y energia toman en cuenta la cantidad de calor sensible de todos los constituyentes involucrados asi como el calor de combustion. Se consideran zonas de transferencia de calor por conveccion o por un mecanismo combinado correctivo-radiante en el hogar de la caldera. La presion en el domo se modela con base en el balance de masa y energia, considerando todas las fuentes y sumideros existentes. La simulacion tambien refleja los transitorios de presion debidos a variaciones termicas, variaciones en la combustion y variaciones en la demanda de vapor. La transferencia de calor por conveccion se considera para todos los bancos de tubos a lo largo de la trayectoria de los gases hacia la chimenea. Se realizaron comparaciones con datos de diseno y operacion de la planta, usando una seleccion de estados transitorios para demostrar la fidelidad del modelo. Se enfoco esta seleccion de estados transitorios al arranque de la unidad, ya que en esta seccion de la operacion se lleva a cabo el rodado y calentamiento de la turbina.

  15. Criterios para la determinación del número de cucharas en una turbina Pelton

    Directory of Open Access Journals (Sweden)

    Octavio Jaramillo Valencia

    2011-02-01

    Full Text Available Los criterios descritos en el presente artículo se aplican en los programas de computador del proyecto de grado "Comportamiento Hidráulico de Cucharas Pelton", calificado con la distinción de meritorio, en el cual a partir de la altura neta, el caudal y la velocidad angular, se determina la geometria de las cucharas. Forma parte del programa de investigación que la Facultad de Ingeniería está llevando a cabo con el propósito de desarrollar turbinas Pelton de baja potencia con la financiación de Colciencias y bajo la dirección del Ingeniero Alvaro Rey Romero.

  16. ANÁLISE DOS PARÂMETROS DE FUNCIONAMENTO E SIMULAÇÃO COMPUTACIONAL EM UM PROTÓTIPO DE TURBINA OPERANDO A AR COMPRIMIDO

    Directory of Open Access Journals (Sweden)

    Wesley Saldanha Nogueira Oliveira

    2016-12-01

    Full Text Available RESUMO. Este trabalho apresenta os resultados iniciais da comparação de alguns parâmetros de funcionamento do protótipo de uma turbina de ação simples, operando com ar comprimido como fluido de trabalho, realizados na unidade do SENAI de Barra do Piraí/RJ. O protótipo foi desenvolvido integralmente no Centro Universitário Geraldo Di Biase - UGB - Campus de Barra do Piraí/RJ, que inicialmente teve como o fluido de trabalho o vapor d’água, que nos testes inicias se mostrou ineficiente. A simulação computacional do sistema foi feita através do software SolidWorks na Universidade Federal Fluminense - UFF - Campus de Volta Redonda/RJ, o que permitiu determinar a faixa de trabalho que apresentou maior eficiência nos resultados experimentais do sistema por meio da relação entre pressão de operação, velocidade angular transmitida pelo fluido ao eixo da turbina e a potência da mesma. Os valores nas simulações em velocidade tangencial na região rotacional apresentaram-se convergentes aos valores experimentais medidos no protótipo.

  17. Software ambient in the partial simulator of total scope of turbine turning; Ambiente de software del simulador parcial de alcance total de rodado de turbina

    Energy Technology Data Exchange (ETDEWEB)

    Daza Velazquez, Ismael; Hernandez Flores, Concepcion; Jimenez Fraustro, Luis Alejandro; Lopez Aguilera, Diana Monica; Nava Lara, Eric; Parra Gomez, Iliana; Santiago Villavicencio, Francisco Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-07-01

    The software tools developed for the partial simulator of total scope for switchboard operators training in turbine turning maneuvering are presented. These tools provide the execution ambient of the mathematical models that reproduce the behavior of the associated phenomena to the turbine operation, which in the same form control that this execution is made in real time by means of an algorithm specially developed for it. Also provides a series of functions that help the instructor to carry on a training session by means of a friendly interface man-machine and of easy use, as well as the option of carrying on self training session and the issuing of an evaluation final report. [Espanol] Se presentan las herramientas de software desarrolladas para el simulador parcial de alcance total para el adiestramiento de operadores tableristas en maniobras de rodado de turbina. Estas herramientas proporcionan el ambiente de ejecucion de los modelos matematicos que reproducen el comportamiento de los fenomenos asociados a la operacion de la turbina, las cuales, asimismo, controlan que dicha ejecucion se realice en tiempo real mediante un algoritmo desarrollado especialmente para ello. Tambien brindan una serie de funciones que auxilian al instructor a llevar una sesion de entrenamiento, mediante una interfaz hombre-maquina amigable y de facil uso, asi como la opcion para realizar una sesion de autoentrenamiento y la generacion de un reporte final de evaluacion.

  18. The decrease of the energy performance for the soiling of the air filters in gas turbines; Disminucion de la eficiencia energetica por ensuciamiento de filtros de aire en turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Ambriz, J. J.; Vargas, M.; Godinez, M.; Gomez, F.; Valdez, L.; Pantoja, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Mexico D. F. (Mexico)

    1995-12-31

    The object of this paper is to study the effect in the turbine output of a gas turbine of the conditions of the compressor air inlet in going through a series of filters. The algorithm for the calculation of the energy losses due to the variation of the pressure drop caused by the filters according to their cleanliness condition. In the first part the series of variables that affect the gas turbines performance are exemplified, afterwards the characteristics of the air flow into a turbine are presented as well as their effects on the system. Later on, the results obtained of the system simulation are presented and compared with a real case. From the results it can be determined, that depending on the system and on the environment conditions the efficiency drop might be up to 3%, in accordance with the filters cleanliness. The maintenance periods strongly depend on the air quality variations at the filter house inlet in the zone where the power plant is located. [Espanol] El presente trabajo tiene por objetivo estudiar el efecto en la potencia generada en una turbina de gas de las condiciones de entrada del aire al compresor de una turbina de gas al pasar por un conjunto de filtros. Se presenta el algoritmo para la determinacion de las perdidas energeticas debidas a la variacion de la caida de presion generada por los filtros de acuerdo con su estado de limpieza. En la primera parte se ejemplifica el conjunto de variables que influyen en la eficiencia de las turbinas de gas, posteriormente se mencionan las caracteristicas de flujo de aire hacia una turbina y se muestran los efectos sobre el sistema. A continuacion se presentan los resultados obtenidos de la simulacion del sistema y se comparan con un caso real. De los resultados se puede apreciar que, dependiendo del sistema y de las condiciones ambientales el decremento en la eficiencia puede ser hasta del 3% en funcion del nivel de limpieza de los filtros. Los periodos de mantenimiento dependen fuertemente de las

  19. Conditioned food aversion to control outbreaks of intoxication by Ipomoea carnea and Turbina cordata in goats

    Science.gov (United States)

    Conditioned food aversion is used to train livestock to avoid the ingestion of toxic plants. This technique was used to control Turbina cordata poisoning in goats in one farm, and to control Ipomoea carnea subsp. istulosa poisoning in another farm. The goats were penned at night and the next mornin...

  20. Turbina eolica para agricultura familiar do semiarido com inovac?es tecnologicas para baixas velocidades de vento

    National Research Council Canada - National Science Library

    Daniel Albiero; Sérgio Daher; Leonardo de Almeida Monteiro; Francisco José Firmino Canafístula

    2014-01-01

    ... eólico para pequenas propriedades do Estado do Ceará com inovações tecnológicas. Todos os sistemas foram concebidos e dimensionados em uma turbina inovadora e apropriada para as pequenas propriedades...

  1. Montagem e instrumentação de uma bancada para turbina hidráulica

    OpenAIRE

    Santander, Olga Lucia Sánchez

    2015-01-01

    A dissertação apresenta o desenvolvimento de uma bancada de ensaio de máquinas hidráulicas para avaliar diversos tipos e configurações de turbinas hidráulicas para dar apoio à formação profissional dos estudantes do curso de Engenharia de Energia. A primeira configuração que está sendo implementada é de uma turbina Indalma. A bancada é composta por uma bomba d'água com vazão regulável, circuito de entrada de água com altura da coluna d'água programável para quatro alturas preestabelecidas, ci...

  2. Diffuse control of gas turbines in power stations of combined cycle; Contral difuso de turbinas de gas en centrales de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez P, Marino; Garduno R, Raul; De Lara J, Salvadror; Castelo C, Luis [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    In this article the application of the technology of the fuzzy logic to the control of gas turbines is presented in order to evaluate it in one of the most difficult processes and with stricter control requirements that exist in the electrical generation industry. For being important for the generation electrical sector, given their use in Comision Federal de Electricidad (CFE), the first selected prototype was the gas turbines model W501 of Westinghouse, installed in the of combined cycle power stations of Dos Bocas, Veracruz, Gomez Palacio, Durango and Tula, Hidalgo, Mexico. The second selected prototype was the one of the turbo gas units type 5001 (that applies to the GE 5001 models and Westinghouse of series 191 and 251). Based on the analysis of the performance of the system of conventional control previously made, the controllers of speed and generation of electrical power were selected to be replaced by diffuse controllers. [Spanish] En este articulo se presenta la aplicacion de la tecnologia de la logica difusa al control de turbinas de gas con el proposito de evaluarla en uno de los procesos mas dificiles y con requerimientos mas estrictos de control que existen en la industria de generacion electrica. Por ser importantes para el sector electrico de generacion, dada su utilizacion en Comision Federal de Electricidad (CFE), el primer prototipo seleccionado fueron las turbinas de gas modelo W501 de Westinghouse, instaladas en la central de ciclo combinado de Dos Bocas, Veracruz, Gomez Palacio, Durango y Tula, Hidalgo, Mexico. El segundo prototipo seleccionado fue el de unidades turbogas tipo 5001 (que aplica a los modelos GE 5001 y Westinghouse de la serie 191 y 251). Basados en el analisis del desempeno del sistema de control convencional realizado previamente, los controladores de velocidad y de generacion de potencia electrica fueron seleccionados para ser sustituidos por controladores difusos.

  3. Rotor optimization of a Francis type hydraulic turbine through the computer flow analysis (CFD); Optimizacion del rodete de una turbina hidraulica tipo Francis a traves del analisis computacional del flujo (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Rosado Tamariz, Erick

    2007-06-15

    basicas para el analisis de flujo y el proceso de optimizacion en las turbinas, los cuales consisten en: modelado de flujo a traves de toda la turbina (conjunto), o bien el modelado de cada componente por separado, obteniendo resultados satisfactorios por ambas metodologias. En la mayoria de los casos implementando el metodo de volumen finito (MVF), con consideraciones de flujo no viscoso, con la implementacion de los modelos de dos ecuaciones para la solucion de las ecuaciones que rigen el flujo turbulento. Asi mismo, se utilizan tecnicas de optimizacion que se basan en la parametrizacion geometrica, el planteamiento de una funcion objetivo y en la disminucion del fenomeno de cavitacion. En el presente trabajo se presenta la optimizacion de un rodete de una turbina hidraulica tipo Francis modelo, considerando tres condiciones de carga (75%, 85% y 100%) a traves de la dinamica de fluidos computacionales (CFD) como parte de un analisis hidraulico para la modernizacion de una unidad de generacion de potencia. Se realiza la optimizacion del rodete de una turbina tipo Francis, mediante un analisis previo de CFD mediante el MVF, considerando los efectos viscosos del fluido y el modelo de turbulencia Sparlat-Allmaras; modelando el distribuidor y el rodete por separado. Posteriormente se realiza la generacion de un modelo parametrico del rodete y se configura la simulacion para la generacion de la base de datos. Finalmente se plantea una funcion objetivo para con ello obtener la geometria optima de los alabes del rodete. Los resultados se presentan en forma grafica donde se muestra la distribucion de presiones del rodete original y el rodete optimizado; de igual forma, se comparan las formas geometricas y los resultados globales de desempeno (potencia y rendimiento) de ambos rodetes.

  4. Estimación del Error en un Medidor de Turbina con Insuficientes Tramos Rectos Estimación del Error en un Medidor de Turbina con Insuficientes Tramos Rectos

    Directory of Open Access Journals (Sweden)

    Francisco Martínez González

    2012-02-01

    Full Text Available In agricultural pumping plants flowmeters are frequently installed with insufficient straight sections of pipe both upstream and downstream from the meter, in order to meet the established installation specifications. It has been found that flowmeter manufacturers do not know the error rate in flow measurements under these no optimal conditions. In 1998, Hanson found that a propeller flowmeter had an error of 3,5 % when it was installed in a position a distance of two pipe diameters downstream from an elbow. This project investigated the performance of a turbine flowmeter under no optimal upstream and downstream conditions (conditions not considered by Hanson. Experiments were carried out in the Hydraulic Laboratory of the University of Guanajuato. Measurements were made in different flowmeter positions considering different flow rates. Results from this project showed that the flowmeter does not have a large error, even if it is installed in an incorrect position. However, lowest error rate is obtained when it was installed in the position recommended by the manufacturer. En pozos agrícolas, frecuentemente se presenta el caso de trenes de descarga con insuficientes tramos rectos para cumplir las especificaciones de instalación de medidores de flujo. Los fabricantes no conocen la variación del error de medición en que se incurre si los medidores se colocan bajo condiciones de insuficientes tramos rectos. Hanson (1998 encontró que un medidor de propela presenta un error de 3,5 % si se coloca con dos diámetros aguas abajo de un codo de 90o. Para conocer el desempeño de un medidor de turbina con poco tramo recto, tanto aguas arriba como aguas abajo (condiciones no consideradas por Hanson se realizaron pruebas en el Laboratorio de Hidráulica de la Universidad de Guanajuato. Se compararon las lecturas del medidor contra las de un tanque volumétrico, colocando el medidor en diferentes posiciones y con varios gastos. Los resultados indican que

  5. Speed control and generation of electric power of a gas turbine by means of fuzzy-logic; Control de velocidad y de generacion de potencia electrica de una turbina de gas mediante logica difusa

    Energy Technology Data Exchange (ETDEWEB)

    Bahamaca Fernandez, Luis Jonathan

    2000-08-01

    ) en una estrategia de control automatico. Los controladores difusos fueron validados mediante el desarrollo de pruebas funcionales en una estructura de simulacion de un modelo matematico no lineal para turbina de gas, ambos en lenguaje de programacion C. Estas pruebas de simulacion realizadas para la evaluacion de una buena regulacion y seguimiento de la velocidad/carga dieron resultados satisfactorios, es decir, los controladores difusos minimizaron los efectos producidos por las perturbaciones programadas del sistema (originadas por las acciones del control) y presentaron un mejor seguimiento a la referencia. Por ello, el sistema de control difuso propuesto presenta un mejor desempeno en comparacion al sistema de control convencional.

  6. Stress analysis in the last stage blade of a geothermal turbine under different excitation conditions; Analisis de esfuerzos en el alabe de la ultima etapa de turbina geotermica bajo diferentes condiciones de excitacion

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Alcazar, Rony Ediberto

    2009-11-15

    The blades of the steam turbines operate below severe conditions of pressure, temperature and steam flow, and at high rotary speeds too. These excitements generate states of stress, which depending on its magnitude and time of application; they can threaten the structural reliability of these mechanical components. In this work a stress analysis is realized in a blade L-0 of a geothermal turbine of low pressure, by means of the finite element method, by the aim to determine the states of static stress caused by the combined action of the centrifugal force and pressure of system flow, and dynamic stresses caused by the harmonic fluctuation in the steam flow. The analysis is realized under two superficial conditions in the blade: without presence of superficial damage and with presence of erosion in the bottom part of the trailing edge. The combined action of these conditions of stress is evaluated by means of an analysis of fatigue. This allows knowing the influence of the stress calculated, on the useful life of the blade. [Spanish] Los alabes de turbinas de vapor operan bajo condiciones severas de presion, temperatura y flujo de vapor, asi como a altas velocidades rotativas. Estas excitaciones generan estados de esfuerzos, que dependiendo de su magnitud y tiempo de aplicacion, pueden amenazar la confiabilidad estructural de estos componentes mecanicos. En este trabajo se realiza un analisis de esfuerzos en un alabe L-0 de una turbina geotermica de baja presion, mediante el metodo de elemento finito, con el objetivo de determinar los estados de esfuerzos estaticos causados por la accion combinada de la carga por fuerza centrifuga y presion de flujo de vapor, y esfuerzos dinamicos causados por la fluctuacion armonica en el flujo de vapor. El analisis se realiza bajo dos condiciones superficiales en el alabe: sin presencia de dano superficial y con presencia de erosion en la parte inferior del borde de salida. La accion combinada de estos estados de esfuerzos se

  7. Numerical simulation by CFD of the behavior of the Inter stage 1 flow in stable state of a gas turbine Frame 7; Simulacion numerica por CFD del comportamiento del flujo en la inter etapa 1 en estado estable de una turbina de gas frame 7

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez R, Alejandro; Lopez H, Juan Arturo R; Mazur Czerwiec, Zdizslaw; Cordero G, Jesus [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2006-07-01

    This technical article presents an analysis including the three-dimensional modeling of the flow channel in the nozzle and the movable blade in order to discover the velocity distribution, temperatures and pressures of the main hot gas flow produced in the inter-stage 1. The aim is to establish key evaluation criteria leading to an opportune repair and therefore smaller operation expenses. Thus, the application of a commercial software of CFD is described to model the channel of the first stage in the gas turbine Frame 7, the geometric architecture is shown in the web of the gas turbine, as well as the border conditions used in the results assessment. [Spanish] Este articulo tecnico presenta un analisis que incluye la modelacion tridimensional del canal de flujo en la tobera y el alabe movil para conocer las distribuciones de las velocidades, temperaturas y presiones del flujo principal de gases calientes que se desarrollan en la inter-etapa 1. El fin es establecer criterios clave de evaluacion que conduzcan a una oportuna reparacion y por ende menores gastos de operacion. Asi, se describe la aplicacion de un software comercial de CFD para modelar el canal de flujo de la primera etapa de una turbina de gas Frame 7, se muestra la arquitectura geometrica y el mallado de la turbina de gas, asi como las condiciones de frontera usadas y la validacion de resultados.

  8. Digital implementation, simulation and tests in MATLAB of the models of Steam line, the turbines, the pressure regulator of a BWR type nucleo electric power plant; Implementacion digital, simulacion y pruebas en MATLAB de los modelos de la linea de vapor, las turbinas y el regulador de presion de una central Nucleoelectrica tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, A. [UNAM, Laboratorio de Analisis de Ingenieria de Reactores Nucleares, DEPFI, Campus Morelos, en IMTA Jiutepec, Morelos (Mexico)]. e-mail: andyskamx@yahoo.com.mx

    2004-07-01

    In this phase of the project they were carried out exhaustive tests to the models of the steam lines, turbines and pressure regulator of a BWR type nucleo electric central for to verify that their tendencies and behaviors are it more real possible. For it, it was necessary to also analyze the transfer functions of the different components along the steam line until the power generator. Such models define alone the dominant poles of the system, what is not limitation to reproduce a wide range of anticipated transitoriness of a power station operation. In the same manner, it was integrated and proved the integrated model form with the models of feeding water of the SUN-RAH, simulating the nuclear reactor starting from predetermined entrances of the prospective values of the vessel. Also it was coupled with the graphic interface developed with the libraries DirectX implementing a specific monitoring panel for this system. (Author)

  9. Calculation of the temperature distribution and thermal stresses in a gas turbine nozzle cooled by air film; Calculo de la distribucion de temperaturas y esfuerzos termicos en una tobera de turbina de gas enfriada por pelicula de aire

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez R, Alejandro; Garcia I, Rafael; Mazur C, Zdislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    The analysis begins with the generation of a computational geometric model of the gas turbine nozzle using reverse engineering techniques. For the obtaining of the original geometry of the blade, a measurement machine by coordinates and computerized numerical control was used. Next, the computational model is converted into a three-dimensional mesh. In advance, a study of boundary conditions was made of the nozzle material as well as of the turbine operating conditions during non-operating cycles, start-ups and shut-downs. On the other hand, with the boundary conditions imposed to the model, the distributions of the temperature and pressures on the aerofoil profile of the nozzle blade were calculated. These results had to be manipulated to be exported to a finite element software (ANSYS); at this point, another nozzle model was elaborated to be able to import the temperature distribution. With the temperatures correctly imported, the simulations for the calculation of the thermal stresses were made in the nozzle. [Spanish] El analisis inicia con la generacion de un modelo geometrico computacional de la tobera de la turbina de gas utilizando tecnicas de ingenieria inversa. Para la obtencion de la geometria original del alabe, se utilizo una maquina de medicion por coordenadas y control numerico computarizado. A continuacion, el modelo computacional es convertido en una malla tridimensional. Con antelacion, se realizo un estudio de las condiciones de frontera, tanto del material de la tobera como de las condiciones de operacion de la turbina, durante ciclos de paro, arranque y disparo. Por otra parte, con las condiciones de frontera impuestas al modelo, se calcularon las distribuciones de las temperaturas y presiones sobre el perfil aerodinamico de la paleta de la tobera. Estos resultados tuvieron que ser manipulados para ser exportados a un software de elemento finito (ANSYS); en este punto, se elaboro otro modelo de la tobera para poder importar la distribucion de

  10. Evaluación exergética de propuestas de disminución de consumo de vapor en usinas azucareras Exergetic evaluation of proposals for steam consumption reduction in sugar factories

    Directory of Open Access Journals (Sweden)

    Dora Paz

    2005-12-01

    Full Text Available Se realizó un modelado exergético, basado en la 2° ley de la Termodinámica, para la evaluación de las operaciones térmicas de Calentamiento-Evaporación-Cristalización (CEC en un ingenio de Tucumán. Una vez resueltos los balances de masa y energía de sistemas CEC, se determinaron los balances de exergía, evaluando las pérdidas de exergía y la eficiencia exergética. Se emplearon ecuaciones y gráficos existentes en la bibliografía para evaluar las propiedades termodinámicas de los flujos intervinientes. Se simularon y compararon con el caso base (zafra 2000, dos propuestas tendientes a disminuir las pérdidas de exergía, considerando: aumento de efectos de evaporación, mayor aprovechamiento de vapores vegetales, aumento en la concentración de melado, empleo de vapor vegetal para la cristalización y reemplazo de turbinas de vapor ineficientes por motores oleohidráulicos y eléctricos. Los resultados mostraron que las menores eficiencias exergéticas se producen en condensadores barométricos de cristalización y evaporación, y en cristalización. La reducción de irreversibilidades en las propuestas analizadas permitiría eliminar el combustible adicional necesario para operar calderas bagaceras antiguas.Exergetic modelling, based on exergetic analysis (2nd law of Thermodynamics, was applied in assessing Heating-Evaporation-Crystallization (H-E-C thermal operations in a cane sugar mill in Tucumán (Argentina. After solving mass and energy balances in H-E-C systems, exergy balance was determined. Exergy losses and exergetic efficiency were calculated. Equations and graphics found in bibliographic sources were used to calculate thermodynamic properties of intervening flows. Two alternatives for reducing exergy losses were simulated and compared with base case (2000 season. These alternatives aimed at the following goals: more evaporation effects, better use of juice vapours, increase in syrup concentration, and replacement of

  11. Changes in steam production due to the reservoir conditions in Cerro Prieto, Baja California; Cambios en la produccion de vapor debido a las condiciones del yacimiento en Cerro Prieto, Baja California

    Energy Technology Data Exchange (ETDEWEB)

    Morales Cardenas, Ramon; Rodriguez Rodriguez, Marco H. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)]. E-mail: marco.rodriguez01@gfe.gob.mx

    2011-07-15

    In more than 35 years of exploitation, thermodynamic conditions have changed in the Cerro Prieto geothermal reservoir. The effects are analyzed of the changes to the reservoir and their consequences to steam production in different field zones. For steam production, the most important features of reservoir fluids are enthalpies and pressures. The evolution of these features is presented in an enthalpy-pressure diagram. Here it can be seen that some reservoir zones have almost reached abandonment conditions. [Spanish] En mas de 35 anos de explotacion el yacimiento geotermico de Cerro Prieto ha experimentado cambios en sus condiciones termodinamicas. En este trabajo se analiza el efecto de esos cambios del yacimiento y su repercusion en la produccion de vapor para las diferentes zonas en las que se ha dividido el campo. Las propiedades mas importantes del fluido en el yacimiento para la produccion de vapor son su entalpia y su presion, por lo que se presenta la evolucion de esas propiedades en un diagrama de presion-entalpia, en el que se observa que hay zonas del yacimiento que estan proximas a alcanzar condiciones de abandono.

  12. Fatigue lifespan of a mobile blade gas turbine with ceramic coating; Vida util por fatiga de un alabe movil de turbina de gas con recubrimiento ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Illescas, Rafael; Z. Mazur Czerwiec, Zdzislaw; Islas Mungarro, Ricardo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rgi@iie.org.mx; mazur@iie.org.mx; rick_iie@terra.com.mx

    2010-11-15

    Fatigue analysis of a gas turbine moving blade made of IN738LC was carried out in order to evaluate useful life time. The life estimation was done from a previous 3D linear finite element analysis where thermal and mechanical stress calculation at high temperatures was done during steady and transient state i.e. normal start ups and shutdowns. Several load histories with different stresses and strains in the blade were used for different cooling conditions including a thermal barrier coating in comparison with to simple blade without such coating. The important effect of high temperatures on the blade material and stress calculations is shown. The analysis is focused on two different critical zones in the blade: the leading edge at the middle of the height and a cooling channel surface, where high stresses were found in numerical analysis as well as in reality. Finally, the benefit of the presence of a thermal barrier coating in the blade life is shown. [Spanish] Se realizo el analisis de fatiga de un alabe movil de turbina de gas fabricado de IN738LC a fin de evaluar su vida util. La estimacion de vida fue realizada a partir de simulaciones lineales de esfuerzos termomecanicos por elemento finito en 3D a altas temperaturas y durante el arranque y paro normal. Se utilizaron diversos historiales de carga, esfuerzos y deformaciones del alabe para diferentes configuraciones de enfriamiento incluyendo el recubrimiento ceramico tipo barrera termica en comparacion con los resultados sin incluir dicho recubrimiento. Se presenta el efecto importante de las temperaturas elevadas en las propiedades de fatiga del material del alabe y en sus esfuerzos. El analisis se centra en dos puntos de interes identificados como criticos: borde de entrada y un canal de enfriamiento, en donde esfuerzos elevados fueron encontrados tanto numericamente como en la realidad. Finalmente se muestra el beneficio del recubrimiento tipo barrera termica en la vida del alabe.

  13. Digitalización del sistema de control de nivel en calentadores y tanques de drenaje de una Central Nuclear

    OpenAIRE

    Acosta García, José Miguel

    2014-01-01

    Contexto Una central nuclear, al igual que cualquier otro tipo de central generadora de energía eléctrica, mediante turbinas de vapor, está basada en un proceso termodinámico. El rendimiento de las mismas es función del salto entálpico del vapor, para mejorarlo las centrales están constituidas por un ciclo compound formado por turbina de alta presión y turbinas de baja presión, y un ciclo regenerativo consistente en calentar el agua de alimentación antes de su introducción a los generad...

  14. Diseño del sistema de lubricación, sistema de inyección de combustible y de una tobera para una turbina de gas

    OpenAIRE

    Manzanares Escalada, Jorge

    2015-01-01

    Este proyecto se realizó en el Laboratorio de Termofluidos, perteneciente al Departamento de Ingeniería Civil Mecánica y nace para poder otorgar una mejor información a los alumnos sobre la turbina de tipo tubular. El proyecto tiene por objetivo diseñar varios componentes de una turbina de gas, la cual se constituye esencialmente, de una cámara de combustión y un turbocompresor. El objetivo es hacer girar el compresor mediante los gases de escape de la cámara de combustión de forma continu...

  15. Flow measurement in a 170-MW hydraulic turbine using the Gibson method; Medicion del flujo de una turbina hidraulica de 170 MW utilizando el metodo Gibson

    Energy Technology Data Exchange (ETDEWEB)

    Urquiza, Gustavo [Universidad Autonoma del Estado de Morelos (Mexico); Adamkowski, Adam [The Szewalski Institute of Fluid-Flow Machinery (Poland); Kubiak, Janusz; Sierra, Fernando [Universidad Autonoma del Estado de Morelos (Mexico); Janicki, Waldemar [The Szewalski Institute of Fluid-Flow Machinery (Poland); Fernandez, J. Manuel [Comision Federal de Electricidad (Mexico)

    2007-07-15

    -tiempo o de Gibson. Este metodo esta basado en el fenomeno del golpe de ariete y es aplicado al caso de una tuberia de presion de tuberia hidraulica. La version del metodo usado en el presente trabajo consiste en la medicion, durante el rechazo total de carga, del historial de tiempo y del cambio de presion en una seccion de la tuberia de presion y relaciona este cambio de presion con el nivel del embalse de la central hidroelectrica. El flujo volumetrico se determina mediante la integracion del incremento de la diferencia de presion medida con respecto al tiempo. La medicion del flujo fue posible gracias a la poca influencia de la entrada del flujo a la tuberia de presion, de 300 m longitud, evitando asi introducir un error considerable en la medicion. Se aplicaron y adoptaron para la medicion los criterios de la norma IEC-41-1991 y experiencias previas. Se utilizo un sistema de adquisicion de datos rapido y eficiente, el cual incluye una tarjeta de 16 bit. El flujo fue calculado usando un programa de computo desarrollado y probado en varios casos anteriores. Los resultados obtenidos con el metodo Gibson fueron utilizados para la calibracion de un sistema de medicion en linea basado en el metodo relativo de Winter-Kennedy. Este ultimo se usa comunmente para el monitoreo continuo del flujo de turbinas hidraulicas, siempre y cuando la calibracion en sitio haya sido realizada usando los resultados de las mediciones de un metodo absoluto. Una vez medido el flujo y la potencia de salida, se calculo la eficiencia para diferentes condiciones de operacion. Se discuten y presentan los resultados obtenidos en una curva, la cual muestra las mejores condiciones de operacion basadas en la mayor eficiencia. Los detalles de la instrumentacion, su instalacion y otros resultados obtenidos se discuten tambien en el presente articulo.

  16. Considerations over the effects caused by a heat recovery system for exhaust gases, adapted to gas turbines originally designed for the operation in a simple cycle; Consideraciones sobre los efectos causados por un sistema de recuperacion de calor de gases de escape, adaptado a turbinas de gas disenadas originalmente para operar bajo un ciclo simple

    Energy Technology Data Exchange (ETDEWEB)

    Cuesta Escobar, Cesar A. [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

    1994-12-31

    This article sets out the considerations on what a heat recovery system from exhaust gases, to already installed and in operation gas turbines, and that were not originally designed to operate with this system, can cause. The potential effects are set forth on the control systems, on the combustion chambers, and in the gas turbine blades, utilized for natural gas pumping or power generation in land installations or in offshore platforms in trying to adapt to them a regenerative cycle or a heating system. Observed effects, fundamentally in the flame stability loop, flow velocity, thermal intensity coefficient, air/fuel relationships and mass flow. Also are presented the consequences that primary production system would suffer, mainly due to the natural gas pumping reduction, the space availability, the fuel consumption, and the maximum amount of heat susceptible to be recovered, comparing the requirements of this in the system. [Espanol] En este articulo se plantean las consideraciones sobre lo que puede provocar un sistema de recuperacion de calor de gases de escape adaptado a turbinas de gas ya instaladas, operando y que no fueron disenadas originalmente para operar con este sistema. Se plantean los probables efectos en los sistemas de control, en las camaras de combustion y en los empaletados de las turbinas de gas usadas para bombeo de gas natural o generacion electrica en instalaciones de tierra o plataformas marinas, al tratar de adaptarseles un ciclo regenerativo o un sistema para calentamiento. Efectos observados, fundamentalmente, en el LOOP de estabilidad de flama, velocidad del flujo, coeficiente de intensidad termica, relaciones aire-combustible y flujo masico. Tambien se presentan las consecuencias que sufriria el sistema primario de produccion debido, principalmente, a la reduccion del bombeo de gas natural, a la disponibilidad de espacio, al consumo de combustible y a la cantidad maxima de calor susceptible de recuperarse, comparada con los

  17. Supervisory system for real time monitoring of transient thermal stresses in turbines rotors; Sistema supervisorio para el monitoreo en tiempo real de esfuerzos termicos transitorios en rotores de turbinas

    Energy Technology Data Exchange (ETDEWEB)

    Urquiza Beltran, Gustavo; Rios Miranda, Edmundo; Venegas Guzman, Ricardo; Alvarez Garcia, Gabriela [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    This article presents a supervisory system that, as its main functions, assists the operator on base of the thermal stresses, monitoring in real time the high pressure (HP) and intermediate pressure rotors (IP) of a steam turbine during the start, shut down and/or sudden load changes. The system is based on a thermal model uni-dimensional integrated to the SIMPER (Information System for the Predictive Maintenance of Rotating Equipment), tested in a 300 MW unit of Comision Federal de Electricidad (CFE). [Espanol] En este articulo se presenta un sistema supervisorio que, como funciones principales, asiste al operador con base en el monitoreo de esfuerzos termicos en tiempo real en los rotores de presion alta (PA) y presion intermedia (PI) de una turbina de vapor durante un arranque, paro y/o variaciones bruscas de carga. El sistema esta basado en un modelo termico unidimensional integrado al SIMPER (sistema informatico para el mantenimiento predictivo de equipo rotatorio), experimentado en una unidad de 300 MW de la Comision Federal de Electricidad (CFE).

  18. Analysis of conjugated heat transfer, in transient state of the first stage of a gas turbine; Analisis de transferencia de calor conjugada, en estado transitorio, de la primera etapa de una turbina de gas

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso; Mazur C, Zdzislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Gallegos Munoz, Armando [Facultad de Ingenieria Mecanica, Electrica y Electronica (FIMEE), Universidad de Guanajuato, Guanajuato (Mexico)

    2007-11-15

    This article presents an analysis of conjugated heat transfer in the first stage of movable blades during the starting of a gas turbine, covering a period of 1,012 seconds. The developed computer model is in 3D and uses as initial and border conditions typical starting curves for stack gases, the cooling air and the angular velocity of the blades. As a result of the numerical predictions, the temperature distributions in stack gases, the trowel of the blade and the cooling air are included, doing emphasis in the results obtained in the solid (body of the blade), since these are used for thermo-mechanical stress analysis and later estimation of the blade residual life. [Spanish] Este articulo presenta un analisis de transferencia de calor conjugada en la primera etapa de alabes moviles, durante el arranque de una turbina de gas, cubriendo un periodo de 1.012 segundos. El modelo computacional desarrollado es en tres dimensiones y utiliza como condiciones iniciales y de frontera curvas de arranque tipicas para los gases de combustion, el aire de enfriamiento y la velocidad angular de los alabes. Como resultado de las predicciones numericas, se incluyen las distribuciones de temperatura en los gases de combustion, la paleta del alabe y el aire de enfriamiento, haciendo enfasis en los resultados obtenidos en el solido (cuerpo del alabe), ya que estos se utilizan para analisis de esfuerzos termomecanicos y posterior estimacion de vida residual del alabe.

  19. Optimización del mantenimiento preventivo utilizando las técnicas de diagnóstico integral. Fundamento teóricopráctico; Optimization of the Preventive Maintenance Using the Technique of Integral Diagnosis. Base Theoretical-Practical

    Directory of Open Access Journals (Sweden)

    Pedro L Hernández Domínguez

    2011-02-01

    Full Text Available Se expone un método para la optimización del mantenimiento preventivo planificado (MPP a partir de laintroducción del mantenimiento basado en la condición (MBC en las turbinas y generadores de vapor de unacentral termoeléctrica cubana, utilizando las técnicas de diagnóstico integral. Se presenta el estado del arte deldesarrollo del mantenimiento y se caracteriza este en las centrales termoeléctricas cubanas; además, se realizaun estudio estadístico de las fallas y se presentan varios casos de estudio con la finalidad que el lector puedacomprender la necesidad de implantación de esta técnica, cuyos únicos costos son la organización de los datosde fallas y la colaboración del personal técnico ligado a las mismas. In this present paper the author exposed a method for the optimization of the planned preventive maintenance(PPM starting from the introduction of the condition based maintenance (CBM in the steam turbines and generatorsin a cuban thermoelectric power station, using the techniques of Integral Diagnosis. In the same one thestate of the art of the development of the maintenance is presented and the last one is characterized in the cubanthermoelectric power station, it is also carried out a statistical study of the failures and several cases of study arepresented with the purpose that the reader can understand the necessity of installation of this technique whoseonly costs belong the organization of the data of failures and the collaboration from the bound technical personnelto the same ones.

  20. Temperature control of a steam generator by means of an hybrid system PID-RLC; Control de las temperaturas de un generador de vapor mediante un sistema hibrido PID-RLC

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Gonzalez, Daniel; Garcia Mendoza, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    A description is made of the design and evaluation of an hybrid control system, formed by a quadratic gaussian linear regulator (QLR) and proportional integral derivative (PID) type regulators. This scheme is used to control the reheater and secondary superheater steam temperatures of a steam generator model with a maximum capacity of 2,150,000 pounds per hour. Once applied to the model of a 300 MW steam power plant, this system showed better results than the traditional schemes and inclusively better than some modern control schemes. This fact characterizes it as a high potential system to be applied to steam power plants. [Espanol] Se describe el diseno y la evaluacion de un sistema de control hibrido, formado por un regulador lineal cuadratico gaussiano (RLC) y reguladores tipo proporcional integral derivativo (PID). Este esquema se utiliza para controlar las temperaturas de vapor del recalentador y sobrecalentador secundario del modelo de un generador de vapor con capacidad maxima de 2,150,000 libras por hora. Una vez aplicado al modelo de una unidad termoelectrica de 300 MW, este sistema produjo mejores resultados que los esquemas tradicionales e incluso mejores que algunos esquemas de control moderno. Esto lo caracteriza como un sistema con un alto potencial para aplicarse a unidades termoelectricas.

  1. Vapor Detector

    Science.gov (United States)

    Waddell, H. M.; Garrard, G. C.; Houston, D. W.

    1982-01-01

    Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

  2. Ahorro de energía por limpieza de las superficies calefactoras en Generadores de Vapor de Centrales Termoeléctricas (CTE).

    OpenAIRE

    Julio Rigoberto González Torres; Roberto Vizcón Toledo

    2010-01-01

    En este trabajo –anterior a la modernización de la combustión con crudo nacional- se analiza desde el punto de vista técnico económico /6/ la variante de limpieza de caldera más favorable teniendo en cuenta la combustión de fuel oil con alto contenido de vanadio mezclado con crudo nacional, donde la oxidación del mismo trae corrosión en las superficies de transferencia de calor. Como objetivo principal se determinó el consum...

  3. Application of monitoring techniques of operational parameters for the implementation of preventive and predictive maintenance programs to gas turbines; Aplicacion de tecnicas de monitoreo de parametros operacionales para la implantacion de programas de mantenimiento predictivo y preventivo en turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Villareal, Julio Cesar

    1998-12-31

    components. These techniques are: hardness testing, liquid penetrant inspection, magnetic particle inspections and metallographic examination. Chapter five describes the boroscopy inspection and its applications for a rotor analysis and gas turbine blades. Chapter six shows the results obtained and give recommendations for the vibration analysis that were carried out at a gas turbine facility. [Espanol] Esta tesis se realiza con la finalidad de implantar un programa de mantenimiento preventivo y predictivo, mediante tecnicas de monitoreo de parametros que permita sistematizar, documentar y administrar las actividades del mantenimiento. La metodologia de mantenimiento aqui descrita, se aplica a las turbinas de gas de la Terminal Maritima Dos Bocas Tabasco, Mexico. El mantenimiento preventivo se basa en la revision periodica de los equipos, mediante listas de inspeccion, donde la idea es detectar problemas que provoquen posibles fallas y realizar la reparacion o ajusted necesarios para evitarlo. Sin embargo enfrenta a la posibilidad de que el equipo este en perfecto estado y al estar en revision, tenga retrasos y problemas de arranque posteriores. El mantenimiento predictivo se basa en tecnicas que permiten la deteccion e identificacion de fallas incipientes en los equipos. Las tecnicas recomendadas en esta tesis son: Analisis de vibraciones; Evaluacion no destructivas e Inspeccion boroscopica. La estructura de la tesis consta de los capitulos siguientes: El capitulo uno describe la importancia de los programas y estrategias del mantenimiento, sus ventajas y desventajas al aplicarlas en las plantas de proceso continuo. Se plantean los procedimientos para el diseno de un programa de mantenimiento. El capitulo dos presenta la manera de planear los recursos y materiales de mantenimiento, las tecnicas de inspecciones aplicados a la turbina de gas, y finalmente se disenan listas de verificacion de inspecciones como herramienta del mantenimiento preventivo. Los capitulos siguientes

  4. State of the art of technologies thermosolar to concentration; Estado del arte de las tecnologias termosolares a concentracion

    Energy Technology Data Exchange (ETDEWEB)

    Ramos Berume, Carlos; Huacuz Villamar, Jorge M; Medrano Vaca, M. Consolacion [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2000-07-01

    focal (tubo metalico receptor). Por el interior de este tubo circula un fluido de trabajo (aceite termico) a temperaturas de hasta 390 grados Celsius, el cual es enviado a intercambiadores de calor para producir vapor sobrecalentado para operar una turbina y generar la energia electrica y Plato Parabolico (PP), contiene una estructura formada por segmentos de espejos que conforman un paraboloide donde en su punto focal (receptor/maquina termica) incide en la radiacion reflejada y se produce energia electrica. En este documento se presenta el estado del arte de las Tecnologias Termosolares a Concentracion (YYC) que permiten identificar sus desarrollos y problematica actual. Ademas, se incluye una descripcion de las perspectivas de mercado, costos de las TTC y las perspectivas tecnologicas.

  5. Diseño y construcción de una turbina de gas para generación de baja potencia (TGBP con ciclo regenerativo a partir de un turbocargador

    Directory of Open Access Journals (Sweden)

    Cesar Eduardo Mondragón Cediel

    2010-01-01

    Full Text Available La ciudad de Cantagallo (Bolívar en Colombia requiere 21kW de energía eléctrica para suplir las necesidades de su población ya que no tiene acceso a la red de interconexión eléctrica como muchas otras ciudades del país. La aplicación de la generación distribuida a partir de turbinas de gas de baja potencia (TGBP para suplir estas necesidades es viable en Colombia, además las TGBP a partir de turbocargadores automotrices suplen completamente los requerimientos de la generación distribuida aislada y de soporte de la red de distribución en plantas, fábricas y edificios; por lo tanto se realiza el dise.o detallado y construcción de una TGBP que genera 30kW, cuyas características específicas y técnicas le permiten ser aplicable como sistema de Generación Distribuida en Colombia a partir de un turbocargador automotriz empleando el ciclo termodinámico regenerativo para disminuir  el consumo espec.fico de combustible (SFC y por lo tanto aumentar la eficiencia del ciclo, con sus respectivos sistemas de inyección de combustible, ignición, lubricación y de adquisición de datos. Se realiza una metodolog.a de dise.o de: TGBP con ciclo regenerativo, de c.maras de combusti.n tubulares y de intercambiadores de calor (recuperadores empleando fuentes bibliográficas especializadas en el desarrollo de motores a reacción a nivel mundial así como software FEA, CFD y tecnologías de fabricación asequibles y encontradas en Colombia.

  6. Atomic vapor density monitor

    Energy Technology Data Exchange (ETDEWEB)

    Sewall, N.; Harris, W.; Beeler, R.; Wooldridge, J.; Chen, H.L.

    1986-09-01

    This report presents information on the Atomic Vapor Density Monitor (AVDM) system that measures the density of a vapor by measuring the absorption of light from a swept-wavelength laser that passes through an atomic vapor stream.

  7. Petroleum Vapor Intrusion

    Science.gov (United States)

    One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

  8. Calibrated vapor generator source

    Science.gov (United States)

    Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.

    1995-09-26

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.

  9. Swainsonine-induced lysosomal storage disease in goats caused by the ingestion of Turbina cordata in Northeastern Brazil.

    Science.gov (United States)

    Dantas, A F M; Riet-Correa, F; Gardner, D R; Medeiros, R M T; Barros, S S; Anjos, B L; Lucena, R B

    2007-01-01

    A disease of the central nervous system in goats was observed in the municipalities of Juazeiro, Casa Nova and Curaça, state of Bahia, and Petrolina, state of Pernambuco, Northeastern Brazil. The disease was produced experimentally in two goats by the administration of dry Turbina cordata mixed with grain. Clinical signs were observed after the ingestion of 62 and 106 g/kg body weight in 28 and 54 days, respectively. The concentration of swainsonine in the plant varied from less than 0.001% to 0.14% (dry weight). Clinical signs of natural and experimental cases included difficulties in standing, ataxia, hypermetria, wide-based stance, intention tremors, spastic paresis mainly in the hind legs, nystagmus, abnormal postural reactions, head tilting, and falling. Diffuse vacuolation of neurons, epithelial cells of pancreas, thyroids, and renal tubules were observed on the histology. From the electron microscopy of Purkinje cells the vacuoles represented dilated lysosomes. These findings demonstrated that T. cordata causes an acquired glycoprotein lysosomal storage disease. The intoxication occurs at least in an area of 27,000 km2 causing severe losses in goats, and some farmers report the disease also in cattle.

  10. Diagnóstico e análise de avarias em geradores síncronos de imanes permanentes aplicados em turbinas eólicas

    OpenAIRE

    Santos, Bruno Miguel Gomes dos

    2012-01-01

    A presente dissertação versa sobre os modos de avarias mais comuns em geradores síncronos de ímanes permanentes (GSIP), aplicados em turbinas eólicas, suas causas e consequências. Por conseguinte, serão referidos os métodos de diagnóstico mais utilizados para a detecção dessas avarias, será também modelizado o GSIP no funcionamento normal e em modo de avaria e por fim será efectuada a validação experimental desse mesmo modelo.

  11. Gas turbine modular helium reactor in cogeneration; Turbina de gas reactor modular con helio en cogeneracion

    Energy Technology Data Exchange (ETDEWEB)

    Leon de los Santos, G. [UNAM, Facultad de Ingenieria, Division de Ingenieria Electrica, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Mexico, D. F. (Mexico)], e-mail: tesgleon@gmail.com

    2009-10-15

    This work carries out the thermal evaluation from the conversion of nuclear energy to electric power and process heat, through to implement an outline gas turbine modular helium reactor in cogeneration. Modeling and simulating with software Thermo flex of Thermo flow the performance parameters, based on a nuclear power plant constituted by an helium cooled reactor and helium gas turbine with three compression stages, two of inter cooling and one regeneration stage; more four heat recovery process, generating two pressure levels of overheat vapor, a pressure level of saturated vapor and one of hot water, with energetic characteristics to be able to give supply to a very wide gamma of industrial processes. Obtaining a relationship heat electricity of 0.52 and efficiency of net cogeneration of 54.28%, 70.2 MW net electric, 36.6 MW net thermal with 35% of condensed return to 30 C; for a supplied power by reactor of 196.7 MW; and with conditions in advanced gas turbine of 850 C and 7.06 Mpa, assembly in a shaft, inter cooling and heat recovery in cogeneration. (Author)

  12. Fault diagnosis in the steam turbo-generator of a Combined Cycle Power Plant; Diagnostico de fallas en el turbogenerador a vapor de una central de generacion de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Flores Abad, Angel

    2006-12-15

    sensores y actuadores. En la actualidad este tipo de centrales tiende a dominar el mercado de generacion electrica por medio de combustibles fosiles, debido a que son las mas eficientes, rentables, de operacion flexible y con menor impacto ambiental. En la CGCC, la turbina de vapor (TV) es una componente fundamental, ya que representa la ganancia del proceso en el sentido de que permite la generacion de energia electrica adicional al aprovechar los gases de escape de la turbina de gas. En caso de que la TV falle, la eficiencia global del proceso se reduce hasta en un 40%. Por lo anterior, en este trabajo se desarrollo un sistema de diagnostico de fallas basado en modelos, de acuerdo a la metodologia FDI (Fault Detection and Isolation) de la teoria de control, con capacidad para detectar y localizar fallas en los sensores y actuadores del turbogenerador a vapor de una CGCC. El enfoque que se utilizo emplea la redundancia analitica con el objetivo de optimizar la redundancia fisica, de manera que sea posible disminuir el costo y espacio extra que implica el utilizar dispositivos repetidos. El diseno del sistema se llevo a cabo usando el analisis estructural AE) que es una herramienta basada en la teoria de grafos y ciencias de la computacion. El AE permitio realizar: analisis de monitoreabilidad, detectabilidad y aislabilidad del proceso; y proporciono la secuencia de computo de las variables no monitoreadas (desconocidas) para obtener las relaciones de redundancia analitica. Para validar el sistema de diagnostico de fallas de la TV, se programaron los algoritmos de deteccion y localizacion de fallas en LabWindows, CVI y se integraron al simulador de la CGCC. Ademas para facilitar al usuario la visualizacion de la presencia de una falla se desarrollo una interfase grafica que indica el elemento con comportamientos anormales, ya sea sensor o actuador.

  13. ESTUDIO DE LAS CONDICIONES DE EXTRACCIÓN POR ARRASTRE CON VAPOR DEL ACEITE ESENCIAL DE LAUREL DE CERA (Morella pubescens STUDY OF EXTRACTION CONDITIONS OF "LAUREL DE CERA" (Morella pubescens ESSENTIAL OIL BY MEANS OF STEAM DISTILLATION

    Directory of Open Access Journals (Sweden)

    OSCAR ARANGO

    2009-12-01

    Full Text Available El laurel de cera (Morella pubescens es un árbol que por sus características resulta muy apropiado para el control de la erosión, y cuyos frutos son utilizados por comunidades campesinas del sur de Colombia para la obtención de una cera que se emplea en el proceso de elaboración de la panela. En esta investigación se estudió el proceso de extracción del aceite esencial de las hojas del laurel de cera mediante la técnica de arrastre con vapor, y su efecto sobre la composición de los metabolitos secundarios volátiles presentes en dicho aceite. Los factores estudiados en el proceso de extracción fueron el tamaño de partícula y el tiempo de extracción, y las variables de respuesta consideradas fueron el área total del cromatograma (cuentas como parámetro indicador de la concentración del aceite y el porcentaje relativo del componente mayoritario. Se determinó que tanto el tiempo como la interacción tiempo - tamaño de partícula tienen efectos significativos (valor de PBecause of its characteristics, the "Laurel de Cera" tree (Morella pubescens proves to be very appropriate for the erosion control. Its fruits are employed as a means to obtain wax that is used in the process of making Panela by rural communities settled in the southern region of Colombia. The extraction process of essential oil from "Laurel de Cera" tree leaves through steam distillation and its effects over the composition of volatile secondary metabolites present were considered for the research. Particle size and extraction time were the studied factors. The chromatogram total area (counts taken as the oil concentration indicator parameter and the relative percentage were the considered response variables. According to the previous information, it was possible to determine that the time as well as the interaction time - particle size have significant effects (P-value <0,05 over the essential oil's concentration. It was also possible to observe a meaningful

  14. 3D analysis of Navier-Stokes in steady state of the behavior of the flow in the Inter stage 1 of a gas turbine Frame 7; Analisis de navier-stokes tridimensional en estado estable del comportamiento del flujo en la inter etapa 1 de una turbina de gas frame 7

    Energy Technology Data Exchange (ETDEWEB)

    Henandez Rosete, Alejandro; Mazur C, Zdzislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    The results of the simulation by CFD (Computacional Fluid Dynamics) realized to the first stage of a gas turbine GE Frame 7 are presented. The analysis includes the 3D modeling of the flow channel in the nozzle and the movable blade to know the velocities distributions, temperatures and pressures of the main hot gas flow that are developed in the Inter stage. The results are influenced by the imposed border conditions in the properties of the main flow, the rotation of the movable blade, as well as the simulation of cooling air injection in the nozzle. The present study focuses in the validation of the model of the meshes of the ensemble nozzle-blade, for later realize an analysis of conjugated heat transfer in a model with ceramic lining type heat barrier (THB) in the movable blade. The analysis is realized in a CFD commercial code oriented to turbo-machinery using the equations of unstable flows 3D of Navier Stokes. [Spanish] Se presentan los resultados de la simulacion por CFD (Computacional Fluid Dynamics) realizada a la primera etapa de una turbina de gas GE Frame 7. El analisis incluye la modelacion tridimensional del canal de flujo en la tobera y el alabe movil para conocer las distribuciones de las velocidades, temperaturas y presiones del flujo principal de gases calientes que se desarrollan en la inter etapa. Los resultados son influenciados por las condiciones de frontera impuestos en las propiedades del flujo principal, la rotacion del alabe movil, asi como la simulacion de inyeccion de aire de enfriamiento en la tobera. El presente estudio se enfoca en la validacion del modelo de la malla del conjunto tobera-alabe, para posteriormente realizar un analisis de transferencia de calor conjugada en un modelo con recubrimiento ceramico tipo barrera termica (TBC) en el alabe movil. El analisis es realizado en un codigo de CFD comercial orientado a turbomaquinaria utilizando las ecuaciones de flujos inestables 3D de Navier Stokes.

  15. Vapor degreasing system

    Science.gov (United States)

    du Fresne, Eugene R. (Inventor)

    1984-01-01

    A vapor degreasing method and apparatus wherein a second cooling coil is used to prevent escape of solvent or solvent vapor from a degreaser. Gaseous refrigerant from the second coil can be released to the freeboard space above the solvent vapor zone to provide a barrier layer.

  16. Intelligent control system for the temperature regulation in a gas turbine of a combined cycle fossil fuel power plant; Sistema de control inteligente para regular la temperatura en la turbina de gas de una central termoelectrica de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Espindola Vasquez, Agustin

    2004-11-15

    logic theory and its performance was evaluated using a non- linear mathematical model that emulates the CTCC behavior. The fuzzy supervision system is integrated by three main modules: Supervision of blades temperature during the starting stage of the UTG; Supervision of blades temperature runback during the power generation stage of the UTG, and Control by Temperature during power generation stage of the UTG. The temperature fuzzy supervisor is implemented in a nonlinear mathematical model that simulates a CTCC. The obtained and analyzed results in the different sceneries of the simulation tests show that the temperature fuzzy supervision system displays a better performance than the obtained with the scheme of conventional supervision. [Spanish] En las Unidades Turbogas (UTG) de una Central Termoelectrica de Ciclo Combinado (CTCC), una de las variables criticas tanto desde el punto de vista operativo como desde el punto de vista de seguridad, es la temperatura de los alabes de la turbina. El mejor desempeno de la unidad turbogas desde el punto de vista de generacion electrica se obtiene cuando es posible lograr la mayor eficiencia termica. Desde el punto de vista de seguridad se busca mantener la temperatura de los alabes en el limite impuesto por el fabricante, garantizando con esto la integridad de las partes internas de la UTG al evitar que esfuerzos termicos considerables decrementen su vida util. Para mantener la temperatura de alabes dentro del limite establecido, el sistema de control de la UTG cuenta con un sistema de supervision de temperatura de alabes, que modifica la referencia de los controladores PI de velocidad o de potencia generada, mismos que regulan la valvula de flujo de combustible a la camara de combustion de la UTG. Este sistema de supervision esta basado en condiciones logicas para generar su salida. En las plantas de proceso cuya operacion es compleja y su comportamiento dinamico es no lineal, las estrategias de control de lazo simple no

  17. Custo de bombas centrífugas funcionando como turbinas em microcentrais hidrelétricas Cost of pumps as hydraulic turbines for micro-scale hydropower

    Directory of Open Access Journals (Sweden)

    Carlos R. Balarim

    2004-04-01

    Full Text Available A implantação de microcentrais hidrelétricas é uma das alternativas para suprir com energia comunidades pequenas e isoladas, situadas normalmente na área rural. O aproveitamento de potenciais hidráulicos de pequeno porte é uma alternativa cada vez mais viável devido não só à falta de recursos financeiros para os grandes empreendimentos, mas também pelo imenso potencial de geração em centrais de pequeno porte, que pouco tem sido aproveitado. O objetivo deste trabalho foi de apresentar uma metodologia simples de engenharia para estimar o custo das Bombas Funcionando como Turbinas (BFTs utilizadas em microcentrais hidrelétricas, que possam ser usadas em estudos preliminares de novos aproveitamentos hidrelétricos, sem uma investigação detalhada dos lugares onde se pretende implantar. Os custos foram obtidos consultando-se diretamente os fabricantes de equipamentos e o mercado da praça de Ponta Grossa - PR. Os resultados mostraram que, para as microcentrais hidrelétricas, sempre que os custos constituírem o aspecto dominante, e para potências até 50 kW, a opção por Bombas Funcionando como Turbinas (BFTs deve ser considerada em lugar das turbinas hidráulicas.The implantation of micro hydroelectric power stations is one of the alternatives to supply energy to small and isolated communities, normally located in rural areas. The use of small load hydraulic potential is an alternative more feasible nowadays, not only because it lacks financial resources for big undertakings, but also, due to the small hydro power station hydraulic generation potential, which just a very small part has been taken advantage of. The objective of this study was to show a simple engineering methodology in order to estimate the electro-mechanic (generating set equipment costs used in micro hydroelectric power plants, which can be applied on preliminary studies about new hydroelectric power stations to be built, without detailed investigation about the

  18. Desenvolvimento de uma turbina de fluxo reversível para uso em usina maremotriz com operação em duplo efeito.

    OpenAIRE

    BOTAN, Antonio Carlos Barkett

    2014-01-01

    Este trabalho apresenta uma proposta de um modelo de turbina de fluxo reversível para o aproveitamento da energia potencial das marés. Sua aplicação no uso de barragens vem a aproveitar a energia potencial oriunda do movimento das marés durante a passagem da água ao reservatório durante a preamar, e sua característica auto retificadora permite o movimento de rotação no mesmo sentido quando a água retorna do reservatório ao oceano, garantindo uma operação de duplo-efeito da usina. O conceito, ...

  19. Degradación de materiales cerámicos en atmósferas de combustión. Dos casos prácticos: quemadores y turbinas de gas

    Directory of Open Access Journals (Sweden)

    García, Eugenio

    2008-12-01

    Full Text Available The use of ceramic materials in energy applications with the aim of power saving through the use of high working temperatures is widely extended due to their better behaviour in those working conditions compared to than metallic materials. However, the combustion environments developed in specific applications can lead to the degradation of such materials. In this work, two ceramic materials employed in these applications are studied; a cordierite material, used as gas radiant burner for its possible application in domestic combustion boilers, and an Y2O3 stabilized ZrO2 coating, used as thermal barrier coating on metallic components of a gas turbine for power generation. The microstructure and phase evolution in both materials after ageing under working conditions allows identifying the main degradation mechanism responsible of the degradation.

    El buen comportamiento de los materiales cerámicos en ambientes corrosivos y a altas temperaturas los sitúa, preferentemente, en todos aquellos procesos industriales que buscan el ahorro energético, en particular los procesos de combustión de gases o de derivados del petróleo. Sin embargo, las atmósferas de combustión que se producen en ciertas aplicaciones producen la degradación de estos materiales. En este trabajo se estudian dos ejemplos de materiales cerámicos empleados en este tipo de aplicaciones; un material de cordierita, empleado como quemador de gas radiante para su posible aplicación en calderas de combustión domésticas y un recubrimiento de ZrO2 estabilizado con Y2O3, empleado como barrera térmica en componentes de una turbina de gas para la producción de energía eléctrica. El estudio de la microestructura, la composición química y de fases cristalinas de ambos materiales después de su degradación en uso permite determinar cuales son los mecanismos que han tenido lugar y qué elementos de la atm

  20. Flow prediction and heat transfer in a cooling square duch of a gas turbine blade using CFD; Predicciones de flujo y transferencia de calor en un conductor de alabe enfriado de turbina de gas utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Urquiza B, Gustavo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Sierra E, Fernando [Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico); Kubiak S, Janusz; Campos A, Rafael [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2003-10-15

    A numerical investigation has been conducted to study the turbulent flow and the heat transfer in a blade turbine coolant passage involving a 180 degrees turn. The study provides a comparison test for two turbulence models. The numerical solution was conducted employing two models for turbulence, the renormalization Group Theory (RNG) and the Reynolds Stress Model (RSM), using a refined grid to model with detail the recirculating flow. Computations are performed with a commercial finite volume code which solves three dimensional, incompressible, Navier-Stokes and Energy equations. At the passage turn, significant secondary flows are present, formed by a pair of symmetrical vortices. Results have been compared against published experimental data for Re = 53 000. Very good agreement is achieved for the prediction of the local static pressure distribution along the passage. A strong effect of rotation has been observed mainly in the flow field as described in detail in the paper. [Spanish] En este trabajo se presenta una investigacion numerica para estudiar el flujo turbulento y la transferencia de calor en un conducto de enfriamiento de un alabes de turbina de gas con giro de 180 grados. El estudio proporciona una comparacion de resultados para dos modelos de turbulencia. La solucion numerica emplea dos modelos de turbulencia: el modelo de esfuerzos de Reynolds (RSM) y el modelo de la teoria del grupo de renormalizacion (RNG), utilizando una malla refinada para modelar con detalle el flujo de recirculacion. Los calculos fueron realizados con un codigo comercial de volumenes finitos el cual resuelve las ecuaciones tridimensionales de Navier-Stoke y de energia para flujo incompresible. En la seccion de giro del conductor, aparecen flujos secundarios significativos, formados por un par de celulas simetricas. Los resultados han sido comparados contra datos experimentales de la literatura para Re = 53 000. se obtuvo un buen acuerdo para la prediccion de la distribucion de

  1. Physical model for vaporization

    OpenAIRE

    Garai, Jozsef

    2006-01-01

    Based on two assumptions, the surface layer is flexible, and the internal energy of the latent heat of vaporization is completely utilized by the atoms for overcoming on the surface resistance of the liquid, the enthalpy of vaporization was calculated for 45 elements. The theoretical values were tested against experiments with positive result.

  2. Vaporizers for medical marijuana.

    Science.gov (United States)

    Mirken, B

    1999-09-17

    A major concern about the medical use of marijuana is the harmful effects that come from smoking it. Vaporizers are designed to release the active ingredients in marijuana without burning it, and therefore do not release the harmful substances found in the marijuana smoke. The Institute of Medicine recommends against the long-term medical use of smoked marijuana because of carcinogens and other chemicals in the smoke. Several vaporizers are on the market, but they have not been tested in the laboratory yet. A review of two vaporizers is given. Contact information is provided.

  3. Nonlinear analysis of thermal stresses of a of first stage nozzle of a gas turbine at full load from the results of an analysis of conjugated heat transference; Analisis no lineal de esfuerzos termicos de una tobera de primera etapa de turbina de gas a plena carga a partir de resultados de un analisis de transferencia de calor conjugado

    Energy Technology Data Exchange (ETDEWEB)

    Perez Hernandez, Efrain [Centro Nacional de Investigacion y Desarrollo Tecnologico (Cenidet), Cuernavaca, Morelos (Mexico); Mazur C, Zdzislaw; Garcia Illescas, R; Hernandez Rossette, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    The gas turbines operate at extremely high temperatures, at high thermal and mechanical stresses, causing that the useful life of the involved components be reduced. In the present article the results realized by previous investigations of temperatures obtained from analysis of heat transfer and flow of fluids of the nozzle by means of the Star-CD program based on finite volumes is presented. Later, the NISA program of finite elements was used to realize the analysis of thermal stresses considering the material plasticity. The methodology employed to determine the material properties variable with the temperature of the super-alloy FSX-414 and the plasticity model used in the structural analysis in the finite element program. The result will be later used in the fatigue analysis for the useful life assessment. [Spanish] Las turbinas de gas operan a temperatura extremadamente altas, a elevados esfuerzos termicos y mecanicos, ocasionando que la vida de los componentes involucrados se reduzca. En el presente articulo se presentan los resultados realizados por previas investigaciones de temperaturas obtenidas a partir de analisis de transferencia de calor y flujo de fluidos de la tobera mediante el programa Star-CD basado en volumenes finitos. Posteriormente, se utilizo el programa NISA de elementos finitos para realizar el analisis de esfuerzos termicos considerando plasticidad del material. Se muestra la metodologia empleada para determinar las propiedades del material variables con la temperatura de la superaleacion FSX-414 y el modelo de plasticidad utilizado en el analisis estructural en el programa de elemento finito. Los resultados seran empleados posteriormente en el analisis de fatiga para la estimacion de vida util.

  4. Second Vapor-Level Sensor For Vapor Degreaser

    Science.gov (United States)

    Painter, Nance M.; Burley, Richard K.

    1990-01-01

    Second vapor-level sensor installed at lower level in vapor degreaser makes possible to maintain top of vapor at that lower level. Evaporation reduced during idle periods. Provides substantial benefit, without major capital cost of building new vapor degreaser with greater freeboard height.

  5. Vapor Control Layer Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-09-08

    This information sheet describes the level of vapor control required on the interior side of framed walls with typical fibrous cavity insulation (fibreglass, rockwool, or cellulose, based on DOE climate zone of construction.

  6. Gasoline Reid Vapor Pressure

    Science.gov (United States)

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  7. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  8. Fuel Vaporization Effects

    Science.gov (United States)

    Bosque, M. A.

    1983-01-01

    A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

  9. Activities for turbine maintenance: planning, implementation and evaluation of inspection results; Actividades para el mantenimiento de la turbina: planificacion, ejecucion y evaluacion de resultados de las inspecciones

    Energy Technology Data Exchange (ETDEWEB)

    Azcue, J.; Sanchez, M. A.; Alvaro, M.

    2014-04-01

    The article will cover the most significant aspects of how Tecnatom carry out the turbine maintenance work, both from the point of view of the inspection itself as the pre-and post tasks associated. Thus, the issues that will be part of the article are the Manual Inspection Service (MISI) and the inspection database, ISI WEB. These tools are essential for planning field work and serve as a guide to run later turbine inspections in different plants. Following this introduction the inspection teams and the techniques used by Tecnatom will be described. finally, the article will contain a small mention about management studies of life and integrity analysis of the turbine that can be performed, as well as involvement in its safe operation that is derived from them. Ultimately, the intention is to provide a comprehensive approach to the issue in question, the turbine maintenance work, so that the reader can get an ideal of the whole process. (Author)

  10. Vapor concentration monitor

    Science.gov (United States)

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  11. Passive Vaporizing Heat Sink

    Science.gov (United States)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

    2011-01-01

    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  12. Desenvolvimento de critérios para seleção de adesivos utilizados na fabricação de pás de turbinas eólicas

    OpenAIRE

    Ricci, Ricardo Pedroso [UNESP

    2012-01-01

    O processo de fabricação das pás de turbinas eólicas envolve a colagem de estruturas fabricadas em plásticos reforçados com fibra de vidro. Neste trabalho foram analisadas os três principais tipos de adesivos estruturais utilizados pelos fabricante de pás (epóxi, poliuretano e metil-metacrilato), com o objetivo de desenvolver critérios que auxiliem na seleção de adesivos e de tratamentos superficiais aplicados às estrutuaras a serem coladas. A caracterização dos adesivos envolveu dois tipos d...

  13. Optimización del sistema de control de las pequeñas centrales hidroeléctricas (primera parte: Factores que dificultan la regulación

    Directory of Open Access Journals (Sweden)

    Luis Jerónimo García Faure

    2011-02-01

    Full Text Available En ocasiones se aborda el problema de la regulación de la velocidad de las turbinas mediante el gasto deagua como un hecho especializado de determinada rama de la ingeniería, y se trata de aplicar a las microy minicentrales las mismas soluciones que para la regulación de otros procesos industriales en loscuales el comportamiento dinámico de los sistemas externos ejerce poca influencia sobre el sistema decontrol utilizado.  In some occasions the problem of the regulation of the speed of hydraulic turbines is approached bymeans of the flow of water as a specialized problem of certain branch of the engineering, and it is appliedto micro hydropower and mini hydropower the same solutions that are applied to the regulation of otherindustrial processes in which the dynamic behavior of the external systems exerts little influence on thecontrol system employed.

  14. Modelo matemático para el diseño aerodinámico de los álabes de una turbina eólica de eje horizontal (TEEH Mathematical Model for Blades Aerodynami c Design of a Horizontal Axis Wind Turbine (HAWT

    Directory of Open Access Journals (Sweden)

    Julio José–Chirinos García

    2016-02-01

    Full Text Available El objetivo de esta investigación es elaborar un modelo matemát ico para el diseño aerodinámico de las palas de una turbina eólica de eje horizontal en forma rápida y confiable qu e facilite a construcción y comportamiento bajo diferentes condiciones. Este resultado se obtuvo por el método inductivo y deductivo partiendo de las teorías aerodinámicas de Glauert y otros introduciéndole modificaciones. Igualmente el d esarrollo del modelo fue programado en una hoja de cálculo que permitió calcular el radio R del rotor, la distribu ción de la cuerda c(r y la variación del ángulo de torsión Ө(r de forma automática. El desarrollo del modelo está estructura do de acuerdo a las siguientes etapas: identificación y definición, conceptualización, formulación e implementación y finalmente la validación del modelo. La validación del modelo fue hecha comparando la geometría de la pala y la potenc ia generada por el rotor con una familia de palas de fabricantes europeos. The research purpose is elaborate a mathematical model fo r blade aerodynamic designing of horizontal axis wind turbine in fast and reliable way to facilitate the construc tion and performance evaluation under different operational conditions. To reach the theoretical and empirical approa ch it was used induction and deduction method starting from aerodynamic theories of Glauert and other researchers, in which necessary modifications were introduced. Also, the development of the model was programmed in aspreadsheet which allows to calc ula table de radio R, the distribution of chord c (r, and the variation of twist angle or pitch Ө (r in automatic way. The development of the model was structured according to the following stages: identification and definition, conceptualization, formulation andimplementation and finally the validation of the m odel. The model validation was made comparing the blade geometry and generated power by the rotor with a blade family of

  15. Modelo matemático para el diseño aerodinámico de los álabes de una turbina eólica de eje horizontal (TEEH; Mathematical Model for Blades Aerodynamic Design of a Horizontal Axis Wind Turbine (HAWT

    Directory of Open Access Journals (Sweden)

    Julio José Chirinos García

    2015-12-01

    Full Text Available El objetivo de esta investigación es elaborar un modelo matemático para el diseño aerodinámico de las palas de una turbina eólica de eje horizontal en forma rápida y confiable que facilite a construcción y comportamiento bajo diferentes condiciones. Este resultado se obtuvo por el método inductivo y deductivo partiendo de las teorías aerodinámicas de Glauert y otros introduciéndole modificaciones. Igualmente el desarrollo del modelo fue programado en una hoja de cálculo que permitió calcular el radio R del rotor, la distribución de la cuerda c(r y la variación del ángulo de torsiónӨ(r de forma automática. El desarrollo del modelo está estructurado de acuerdo a las siguientes etapas: identificación y definición, conceptualización, formulación e implementación y finalmente la validación del modelo. La validación del modelo fue hecha comparando la geometría de la pala y la potencia generada por el rotor con una familia de palas defabricantes europeos.The research purpose is elaborate a mathematical model for blade aerodynamic designing of horizontal axis wind turbine in fast and reliable way to facilitate the construction and performance evaluation under different operational conditions. To reach the theoretical and empirical approach it was used induction and deduction method starting from aerodynamic theories of Glauert and other researchers, in which necessary modifications were introduced. Also, the development of the model was programmed in aspreadsheet which allows to calcula table de radio R, the distribution of chord c (r, and the variation of twist angle or pitch Ө (r in automatic way. The development of the model was structured according to the following stages: identification and definition, conceptualization, formulationandimplementation and finally the validation of the model. The model validation was made comparing the blade geometry and generated power by the rotor with a blade family of European

  16. Water vaporization on Ceres

    Science.gov (United States)

    A'Hearn, Michael F.; Feldman, Paul D.

    1992-01-01

    A search is presently conducted for OH generated by the photodissociation of atmospheric water vapor in long-exposure IUE spectra of the region around Ceres. A statistically significant detection of OH is noted in an exposure off the northern limb of Ceres after perihelion. The amount of OH is consistent with a polar cap that might be replenished during winter by subsurface percolation, but which dissipates in summer.

  17. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  18. Role of co-vapors in vapor deposition polymerization.

    Science.gov (United States)

    Lee, Ji Eun; Lee, Younghee; Ahn, Ki-Jin; Huh, Jinyoung; Shim, Hyeon Woo; Sampath, Gayathri; Im, Won Bin; Huh, Yang-Il; Yoon, Hyeonseok

    2015-02-12

    Polypyrrole (PPy)/cellulose (PPCL) composite papers were fabricated by vapor phase polymerization. Importantly, the vapor-phase deposition of PPy onto cellulose was assisted by employing different co-vapors namely methanol, ethanol, benzene, water, toluene and hexane, in addition to pyrrole. The resulting PPCL papers possessed high mechanical flexibility, large surface-to-volume ratio, and good redox properties. Their main properties were highly influenced by the nature of the co-vaporized solvent. The morphology and oxidation level of deposited PPy were tuned by employing co-vapors during the polymerization, which in turn led to change in the electrochemical properties of the PPCL papers. When methanol and ethanol were used as co-vapors, the conductivities of PPCL papers were found to have improved five times, which was likely due to the enhanced orientation of PPy chain by the polar co-vapors with high dipole moment. The specific capacitance of PPCL papers obtained using benzene, toluene, water and hexane co-vapors was higher than those of the others, which is attributed to the enlarged effective surface area of the electrode material. The results indicate that the judicious choice and combination of co-vapors in vapor-deposition polymerization (VDP) offers the possibility of tuning the morphological, electrical, and electrochemical properties of deposited conducting polymers.

  19. Tomography analysis of flames: characterization of LPP gas turbines; Analise de chamas por tomografia: caracterizacao de turbinas a gas LPP

    Energy Technology Data Exchange (ETDEWEB)

    Costa, F.S.; Carvalho Junior, J.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Caldeira Pires, A.; Anacleto, P. [Instituto Superior Tecnico, Lisbon (Portugal)

    1998-07-01

    The general use of non intrusive techniques, and the particular use of optical measurements allow reactive flow analysis without any changes. The tomographic reconstruction of mono and multi chromatic flames can be used for a deep characterization of the reaction zone. This work analyses the the images obtained in the 431 and 514 mm wavelengths, for respectively the C 2 and C H radicals obtaining the three dimensional distribution of these scalar values in the flame region, in a LPP (lean pre-vaporized premixed combustion) type combustor, under atmospheric pressure operation. With and without swirl flows were considered for two oxidant/fuel O/C ratios. The relationship between C 2 and C H radicals luminous intensity was characterized aiming the local O/C fraction calculation using tomographic reconstruction of the obtained images. The analysis performed on a LPP combustor, with the model developed in the Instituto Superior Tecnico de Lisboa, allows a deep knowledge on the poor combustion conditions in aeronautic turbines, with emphasis on the mixture quality, aiming basically the N Ox emission reduction. (author)

  20. Vapor spill pipe monitor

    Science.gov (United States)

    Bianchini, G. M.; McRae, T. G.

    1983-06-01

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote IR gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote IR sensor which measures the gas composition.

  1. Impactos ambientales, sociales y económicos de las Pequeñas Centrales Hidroeléctricas (PCH) en Antioquia

    OpenAIRE

    Osorio Londoño, Iverson

    2017-01-01

    Después del racionamiento que sufrió Colombia entre 1992 y 1993, el Gobierno buscó impulsar la generación de energía a través de fuentes no convencionales que permitieran suministrar la energía suficiente que el país demanda, situación que impulso la utilización de las pequeñas centrales hidroeléctricas (en adelante PCH) -- Una PCH es una pequeña unidad generadora de energía que aprovecha el agua de un afluente a través de una caída o pendiente, buscando que el líquido abata una turbina para ...

  2. Student Exposure to Mercury Vapors.

    Science.gov (United States)

    Weber, Joyce

    1986-01-01

    Discusses the problem of mercury vapors caused by spills in high school and college laboratories. Describes a study which compared the mercury vapor levels of laboratories in both an older and a newer building. Concludes that the mercurial contamination of chemistry laboratories presents minimal risks to the students. (TW)

  3. Metal vaporization from weld pools

    Science.gov (United States)

    Block-Bolten, A.; Eagar, T. W.

    1984-09-01

    Experimental studies of alloy vaporization from aluminum and stainless steel weld pools have been made in order to test a vaporization model based on thermodynamic data and the kinetic theory of gases. It is shown that the model can correctly predict the dominant metal vapors that form but that the absolute rate of vaporization is not known due to insufficient knowledge of the surface temperature distribution and subsequent condensation of the vapor in the cooler regions of the metal. Values of the net evaporation rates for different alloys have been measured and are found to vary by two orders of magnitude. Estimated maximum weld pool temperatures based upon the model are in good agreement with previous experimental measurements of electron beam welds.

  4. Vaporization of perfluorocarbon droplets using optical irradiation

    National Research Council Canada - National Science Library

    Strohm, Eric; Rui, Min; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael

    2011-01-01

    .... Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization using a method we term optical droplet vaporization (ODV...

  5. A Citizen's Guide to Vapor Intrusion Mitigation

    Science.gov (United States)

    This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

  6. En defensa de la máquina de vapor

    OpenAIRE

    Pérez del Río, José

    1983-01-01

    Esta tesis tiene el doble objeto de explicar porqué las máquinas de vapor desaparecieron casi totalmente y de demostrar como y porqué hay que volver a ellas, principalmente quemando carbón, todo ello para inducir a su aplicación solamente en aquellas potencias que en Marina se consideran pequeñas, es decir, que no sobrepasen los cinco mil caballos.Con tal fin han de aplicarse como es obvio, los conocimientos actuales pero tomando cuidadosamente en cuenta las experiencias, positivas y negativa...

  7. Detecção de instabilidades termoacústicas em câmaras de combustão do Tipo RQL para aplicação em turbinas a gás

    OpenAIRE

    Dener Silva de Almeida

    2007-01-01

    O objetivo do seguinte trabalho é um novo modelo de câmara de combustão do tipo RQL ("Rich-Quench-Lean" na língua inglesa) para turbinas a gás. A combustão acontece em duas fases; a primeira com deficiência de oxidante ou rica em combustível, e a segunda é pobre em combustível. Esta estrutura de combustão permite a conciliação de baixas emissões de NOx e produtos de combustão de oxidação parcial, como monóxido de carbono, hidrocarbonetos não queimados e fuligem. A idéia dos combustores RQL tr...

  8. Diseño de una turbina Twin radial de impulso unidireccional para sistemas OWC de energía undimotriz

    OpenAIRE

    Rodríguez García, Laudino

    2014-01-01

    El artículo presenta el estudio del rendimiento energético de un sistema de aprovechamiento de la energía de las olas (undimotriz). El estudio comienza planteando un prototipo de equipo y se estudia su comportamiento bajo la acción de las olas de diferentes intensidades. Se obtienen las curvas de rendimiento que permiten hacer una comparación con las de otros dispositivos existentes. De los resultados obtenidos, se extraen las conclusiones y se analizan las opciones de mejora.

  9. Supercritical microgravity droplet vaporization

    Science.gov (United States)

    Hartfield, J.; Curtis, E.; Farrell, P.

    1990-01-01

    Supercritical droplet vaporization is an important issue in many combustion systems, such as liquid fueled rockets and compression-ignition (diesel) engines. In order to study the details of droplet behavior at these conditions, an experiment was designed to provide a gas phase environment which is above the critical pressure and critical temperature of a single liquid droplet. In general, the droplet begins as a cold droplet in the hot, high pressure environment. In order to eliminate disruptions to the droplet by convective motion in the gas, forced and natural convection gas motion are required to be small. Implementation of this requirement for forced convection is straightforward, while reduction of natural convection is achieved by reduction in the g-level for the experiment. The resulting experiment consists of a rig which can stably position a droplet without restraint in a high-pressure, high temperature gas field in microgravity. The microgravity field is currently achieved by dropping the device in the NASA Lewis 2.2 second drop tower. The performance of the experimental device and results to date are presented.

  10. Understanding Latent Heat of Vaporization.

    Science.gov (United States)

    Linz, Ed

    1995-01-01

    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  11. Microenvironmental exposure to mercury vapor

    Energy Technology Data Exchange (ETDEWEB)

    Stopford, W.; Bundy, S.D.; Goldwater, L.J.; Bittikofer, J.A.

    1978-05-01

    Work area and breathing zone samples were collected in a factory utilizing metallic mercury and analyzed for mercury vapor content. Breathing zone samples averaged several fold higher in concentration than concurrent area samples, reflecting a ''microenvironmental'' exposure to mercury vapor, presumably from contaminated clothing and hands. Blood and corrected total urine mercury values correlated well with the average microenvironmental exposure level for each worker. Measurements of unbound mercury in urine samples were sensitive at picking up minimal exposures. Excessive amounts of unbound mercury were not found in the urine, even with wide day-to-day swings in microenvironmental mercury vapor levels, suggesting that the human body can adapt to a chronic, moderate exposure to mercury vapor.

  12. El gran músculo mecánico: la máquina de vapor

    OpenAIRE

    Valencia Giraldo, Asdrúbal

    2001-01-01

    Se hace un estudio de los antecedentes, génesis, concepción y desarrollo de la máquina de vapor. Se analizan las consecuencias técnicas, tecnológicas, científicas, industriales, económicas y sociales de la utilización de la máquina de vapor, así como su influjo en la modelación del mundo moderno y las ideas de la civilización industrial.

  13. Conventional and intelligent generalized supervisory control for combined cycle generating power stations.; Control supervisiorio generalizado convencional e inteligente para centrales de generacion de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, Miguel A; Sanchez P, Marino [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Gonzalez Rubio S, Jose L [Cento Nacional de Investigacion y Desarrollo Tecnologico (Cenidet), Cuernavaca, Morelos (Mexico)

    2005-07-01

    Under the expectations of expansion of electric power generation in Mexico, this work exposes the development of a conventional and intelligent generalized supervisory control (CSG) for a combined cycle generation power plant. This one allows to obtain the optimal operation of the power plant through the automatic starting of the generating units and to obtain the maximum possible amount of electrical power in automatic and safe form. For the development of the CSG a control loop by temperature was implemented for the gas turbine system and a control loop by strangled pressure for the gas turbine and a control loop by strangled pressure for the steam turbine. The design of these supervisory systems was made with base in the critical limits on the involved variables of the process: blading average temperature, for the gas turbine (GT) and strangled pressure for the steam turbine (ST) [Spanish] Bajo estas expectativas de expansion de generacion de energia en Mexico, este trabajo expone el desarrollo de un control supervisorio generalizado (CSG) para una central generacion de ciclo combinado. Este permite lograr la operacion optima de la planta a traves del arranque automatico de las unidades generadoras y obtener la maxima cantidad posible de potencia electrica en forma automatica y segura. Para el desarrollo del CSG se implanto un lazo de control por temperatura para el sistema de turbina de gas y un lazo de control por presion estrangulada para la turbina de gas y un lazo de control por presion estrangulada para la turbina de vapor. El diseno de estos sistemas supervisorio se realizo con base en los limites criticos de las variables del proceso involucradas: temperatura promedio de empaletado para la turbina de gas (TG) y presion estrangulada para la turbina de vapor (TV)

  14. Las Sinapsis

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Duque Parra

    1997-12-01

    Full Text Available

    Introducción

    El estudio del sistema nervioso considera entre múltiples conexiones, aquéllas de carácter bioquímico que se median a través de sustancias elaboradas por las neuronas y que reciben la denominación de neurotransmisores’, dichas sustancias se vierten en las zonas de resquicio neuromuscular, neuroneuronal o neuroglandular, para modificar las condiciones de membrana y permitir la continuidad de los potenciales de acción (por creación de nuevos potenciales en las células subsiguientes, de la neurona hacia el órgano blanco.

    La integridad de los diversos elementos de la “zona de unión funcional” o sinapsis, asegura la adecuada comunicación entre el sistema nervioso y la mayoría de los elementos restantes del organismo humano.

    Las alteraciones de los elementos de las sinapsis, conllevan a la génesis de estados variables fisiológicos y patológicos somáticos, psicosomáticos o psíquicos, inconsecuentes con el estado de homeostasis.

    Las moléculas que se vierten en las hendiduras sinápticas, sirven, por tanto, de transductoras para efectos elementales (como los reflejos y en las estrategias complejas (como los de la actividad intelectual.

    Antecedentes

    Ya desde los tiempos de Galeno, se sabía que los nervios eran los responsables de la rápida comunicación entre el cuerpo y el cerebro; el estudio de las sinapsis nos remonta de manera indirecta a
    1791, fecha en la que Luigi Galvani, descubrió en sus experimentos con ancas de ranas, que entre los eventos eléctricos y los ocurridos en los nervios, existía una relación evidente (28,37,45’, los experimentos de Galvani se han refinado con el paso del tiempo, en nuestro siglo por ejemplo, el desarrollo del osciloscopio de rayos catódicos combinado con un amplificador potente, ha permitido medir las débiles y variables corrientes bioeléctricas de los

  15. Pequenas y microcentrales hidroelectricas: alternativa real de generacion electrica

    National Research Council Canada - National Science Library

    Sierra Vargas, Fabio Emiro; Sierra Alarcon, Adriana Fernanda; Guerrero Fajardo, Carlos Alberto

    2011-01-01

    ...), concentrando la descripcion en tres aspectos: las turbinas mas usadas, las caracteristicas de los generadores y una breve descripcion de la legislacion colombiana respecto a la pequena generacion...

  16. Hidro turbina u Venturijevoj cijevi

    OpenAIRE

    PUHARIĆ, Mirjana; KOZIĆ, Mirko; KUTIN, Marina; RISTIĆ, Slavica

    2009-01-01

    U radu su prikazani rezultati istraživanja hidroturbine u Venturijevoj cijevi za zadani broj okretaja i zadanom brzinom vode na ulazu u cijev. Rezultati su dobiveni komercijalnim softverom za numeričku dinamiku fluida. Ispitivanje je obuhvatilo usporedbu snage koju daju jedna i dvije suprotno smjerno rotirajuće hidroturbine u Venturijevoj cijevi. Numeričke simulacije za dvije turbine koje se okreću u suprotnim smjerovima s jednakim kutnim brzinama pokazale su da se javlja znatan pad snage ...

  17. Estimated vapor pressure for WTP process streams

    Energy Technology Data Exchange (ETDEWEB)

    Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-01-01

    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

  18. Water vapor adsorption on goethite.

    Science.gov (United States)

    Song, Xiaowei; Boily, Jean-François

    2013-07-02

    Goethite (α-FeOOH) is an important mineral contributing to processes of atmospheric and terrestrial importance. Their interactions with water vapor are particularly relevant in these contexts. In this work, molecular details of water vapor (0.0-19.0 Torr; 0-96% relative humidity at 25 °C) adsorption at surfaces of synthetic goethite nanoparticles reacted with and without HCl and NaCl were resolved using vibrational spectroscopy. This technique probed interactions between surface (hydr)oxo groups and liquid water-like films. Molecular dynamics showed that structures and orientations adopted by these waters are comparable to those adopted at the interface with liquid water. Particle surfaces reacted with HCl accumulated less water than acid-free surfaces due to disruptions in hydrogen bond networks by chemisorbed waters and chloride. Particles reacted with NaCl had lower loadings below ∼10 Torr water vapor but greater loadings above this value than salt-free surfaces. Water adsorption reactions were here affected by competitive hydration of coexisting salt-free surface regions, adsorbed chloride and sodium, as well as precipitated NaCl. Collectively, the findings presented in this study add further insight into the initial mechanisms of thin water film formation at goethite surfaces subjected to variations in water vapor pressure that are relevant to natural systems.

  19. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  20. Las Farmacodependencias

    OpenAIRE

    José Francisco Socarrás

    1994-01-01

    Ahora, cuando la Corte Constitucional ha despenalizado al farmacodependiente por el consumo de drogas, conviene informar sobre las consecuencias perjudiciales de estas. A quienes deseen un conocimiento detallado al respecto, les recomiendo documentarse en “Enciclopedia de Psiquiatría”, publicada por “El Ateneo” en Buenos Aires.

    El Capítulo respectivo es del doctor Daniel L. Murguia. El denominador corriente de su abuso es sencillamente la dependencia, nombre propues...

  1. 78 FR 42595 - Marine Vapor Control Systems

    Science.gov (United States)

    2013-07-16

    ... clarified the location of the gas injection and mixing arrangement relative to the vapor processing unit or... Parts 35 and 39 Marine Vapor Control Systems; Final Rule #0;#0;Federal Register / Vol. 78 , No. 136... Parts 154, 155, and 156 46 CFR Parts 35 and 39 RIN 1625-AB37 Marine Vapor Control Systems AGENCY: Coast...

  2. Alternative analysis to increase the power in combined-cycle power plants; Analisis de alternativas para el incremento de potencia en plantas termoelectricas de Ciclo Combinado

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco Cruz, Hector; Arriola Medellin, Alejandro M. [Gerencia de Procesos Termicos, Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: hpacheco@iie.org.mx; aarriola@iie.org.mx

    2010-11-15

    The electricity industry traditionally had two thermodynamic cycles for power generation: conventional steam turbine (Rankine cycle) used to supply a base load during the day, and gas turbines (Brayton cycle), for its speed response, normally used to cover peak loads. However, to provide variable peak loads, the gas turbine, as a volumetric machine is affected by the change in air density by changing the combustion temperature. This paper shows the scheme of integration of both systems, that it's known as combined cycle and the different options that would have these power plants, to maintain or increase their power in variable ambient conditions. It analyzes different options, such as: 1. Supplementary fire in the stove. 2. Air cooling intake in the gas turbine (evaporation system or mechanical system). 3. Steam injection in the combustion chamber. [Spanish] La industria electrica tradicionalmente a contado con dos ciclos termodinamicos para generacion electrica: las turbinas convencionales de vapor (ciclo de Rankine) se utilizan para suministrar una carga base durante el dia, y las turbinas de gas (ciclo de Brayton), por su rapidez de respuesta, se utilizan normalmente para cubrir las cargas pico. Sin embargo, para suministrar las cargas variables pico, la turbina a gas, por ser una maquina volumetrica, se ve afectada por el cambio de la densidad del aire de combustion al cambiar la temperatura ambiente. En este trabajo se muestra el esquema de integracion de ambos sistemas, en lo que se conoce como ciclo combinado y las diferentes opciones que tendrian estas plantas de generacion electrica para mantener o incrementar su potencia en condiciones ambiente variable. Para ello se analizan diferentes opciones, tales como: 1.- Combustion suplementaria en el recuperador de calor. 2.- Enfriamiento del aire de admision a la turbina de gas (mediante un sistema de evaporacion o mediante un sistema mecanico). 3.- Inyeccion de vapor a la camara de combustion. Palabras

  3. Las denominaciones de las ocupaciones

    Directory of Open Access Journals (Sweden)

    Jesus Emilio Castañeda

    1990-04-01

    Full Text Available RESUMEN El propósito de este artículo, es mostrar al lector la forma como en nuestro ámbito existen diversos factores que han permitido la proliferación de maneras de llamar las ocupaciones. Aspectos regionales, la tradición, clases de organización, situaciones románticas, adjetivización de los cargos, peyorización  son entre otras razones que han generado  la creación de serie de sinónimos, de las ocupaciones, objeto de estudio de la sociologia del trabajo y de la administración de los recursos humanos.

  4. Las emociones y las TIC

    OpenAIRE

    Enríquez, Silvia Cecilia

    2014-01-01

    Tal vez este pueda resultar un tema sorprendente y, sin embargo, hay abundante bibliografía al respecto. Es posible que no nos lo hayamos planteado nunca, pero nuestra reacción ante el empleo de las TIC es determinante a la hora de medir los resultados que logremos en el aprendizaje que debemos hacer para poder incorporarlas a nuestra tarea. Docentes en Línea

  5. Las obras de acondicionamiento del Salto del Mont-Cenis

    Directory of Open Access Journals (Sweden)

    Vié, Georges

    1969-06-01

    Full Text Available The new dam at Mont Cenis has increased to water volume in the reservoir from 32 to 320 million m3 and provides a potential energy of 650.000 million Mp x m. This article describes the work involved in the construction of this project. Among other features, the water has been led to the reservoir along a network of varying cross-section, and of 28 km total length. The pressure conduit has been designed for a flow rate of 51 m3/s, its diameter varying between 4 and 5 m. The new power stations at Villarodin are fed by a pipe 3.6 km in length and 3 m in diameter. This conduit runs along a trench and is isolated from the ground, because of the gypsum and anhydrites contained in the soil. Its weight is 10.000 Mp, which is a European record. The power station comprises to vertical Pelton turbines of 195 MVA each, and a yearly output of 485 kWh.La capacidad de la nueva presa del Mont-Cenis ha aumentado con estas obras desde 32 hasta 320 millones de m3, permitiendo el abastecimiento de una energía potencial de 650.000 millones de Mp x m. En el artículo se describen las obras y operaciones necesarias para ello; entre otras, que las aguas captadas han sido llevadas al embalse por una red de galerías de sección variable de 28 km de longitud; y que la conducción forzada, de 18 km de longitud, fue dimensionada para un caudal de 51 m3/s, con un diámetro comprendido entre 4 y 5 metros. Las nuevas centrales de Villarodin están alimentadas por una desviación de 3,6 km de longitud y 3 m de diámetro. Este conducto, colocado en un foso inclinado para aislarlo del ter reno, en esa zona de yesos y anhidritas, principalmente, tiene un peso de 10.000 Mp, lo que constituye un récord europeo. La Central comprende dos grupos verticales de turbinas Pelton de 195 MVA cada uno, con una productividad de 485 millones de kWh.

  6. Las Farmacodependencias

    Directory of Open Access Journals (Sweden)

    José Francisco Socarrás

    1994-09-01

    Full Text Available

    Ahora, cuando la Corte Constitucional ha despenalizado al farmacodependiente por el consumo de drogas, conviene informar sobre las consecuencias perjudiciales de estas. A quienes deseen un conocimiento detallado al respecto, les recomiendo documentarse en “Enciclopedia de Psiquiatría”, publicada por “El Ateneo” en Buenos Aires.

    El Capítulo respectivo es del doctor Daniel L. Murguia. El denominador corriente de su abuso es sencillamente la dependencia, nombre propuesto por la Organización Mundial de la Salud, definido como el “estado psíquico y a veces físico causado por la interacción entre un organismo vivo y un fármaco”. Su carácter esencial es el impulso psicofísico a consumir el producto en forma continua o periódica, con el fin de experimentar los efectos que acarrea y evitar los malestares de su privación. Todas las drogas del respectivo género, consumidas a dosis altas, tienen efectos psicotóxicos que alteran la conducta y en algunos casos conducen a la muerte.

    Los expertos de la Organización Mundial califican las mencionadas sustancias en seis grupos, a saber:

    1. Morfina y opiáceas, los cuales crean dependencia física y psicológica, con tolerancia precoz, necesidad de aumentar las dosis y síndrome de abstinencia bastante peligroso. Entre los derivados se cuentan los siguientes: Hidromorfina (Dilaudid; oximorfina (Nurmophan; heroína,
    éter diacético de la morfina (Diacetilmorfina; codeína (Metilmorfina; hidrocodeína (Hicadan’ oxicodeína (Perdocan. Los efectos de los opiáceo~ son los siguientes: analgesia, depresión respiratoria y espasmo gastrointestinal. Las dosis tóxicas pueden provocar convulsiones.

    2. Barbitúricos, alcohol y sedantes como el fenobarbital, que provocan así mismo dependencia física.

    3. Anfetaminas, en particular la Bencedrina inhalante, que acarrea dependencia psicológica.

    4. Cocaína, cuya dependencia psíquica es tal que muchos

  7. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  8. Recent advances in vapor intrusion site investigations.

    Science.gov (United States)

    McHugh, Thomas; Loll, Per; Eklund, Bart

    2017-12-15

    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Vaporization chambers and associated methods

    Science.gov (United States)

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  10. Chemical vapor deposition of sialon

    Science.gov (United States)

    Landingham, R.L.; Casey, A.W.

    A laminated composite and a method for forming the composite by chemical vapor deposition are described. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200/sup 0/C; and impinging a gas containing N/sub 2/, SiCl/sub 4/, and AlCl/sub 3/ on the surface.

  11. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-10-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln(R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  12. Vaporization Would Cool Primary Battery

    Science.gov (United States)

    Bhandari, Pradeep; Miyake, Robert N.

    1991-01-01

    Temperature of discharging high-power-density primary battery maintained below specified level by evaporation of suitable liquid from jacket surrounding battery, according to proposal. Pressure-relief valve regulates pressure and boiling temperature of liquid. Less material needed in cooling by vaporization than in cooling by melting. Technique used to cool batteries in situations in which engineering constraints on volume, mass, and location prevent attachment of cooling fins, heat pipes, or like.

  13. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-11-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  14. Análisis de la redundancia en la generación de vapor con parámetros inferiores en un monobloque de 64 MW // Analysis of redundancy in the steam generation with inferior parameters in an unit of 64 MW.

    Directory of Open Access Journals (Sweden)

    A. Paneque Matos

    2000-10-01

    Full Text Available La necesidad del país de mantener la generación eléctrica a fin de evitar los cortes de servicio planificados e imprevistos,debido a la difícil situación económica actual, obliga a buscar soluciones que al menos sirvan de paliativo temporal a estadesagradable situación. En una central termoeléctrica ubicada en el perímetro de la ciudad, se presentó la situación de queproducto de un accidente, un bloque quedó sin turbogenerador, estando su generador de vapor en magníficas condicionesde explotación; y que otro bloque presentaba muchas salidas forzosas fuera de servicio producto de una insuficientereparación de su generador de vapor. La carencia de fondos para acometer una efectiva reparación, hizo pensar en elanálisis de la posibilidad de utilizar la caldera de una unidad para alimentar el turbogenerador de la otra. En el presentetrabajo se muestran los cálculos correspondientes para determinar aproximadamente el comportamiento de la turbina en lasnuevas condiciones impuestas, se realizó un análisis de fiabilidad del sistema propuesto y se utilizó la simulación comoherramienta para modelar el proceso.Palabras claves: centrales termoeléctricas, fiabilidad, eficiencia, turbina de gas, caldera._______________________________________________________________________Abstract:The necessity of Cuba to maintain the electric generation in order to avoid the interruption of service in planned oraccidental way, due to the difficult current economic situation, forces to solutions that at least serve for temporary palliativeto this unpleasant situation. In a thermoelectric power station located in the perimeter of the city, a situation was presenteddue to an accident, a block with fail in the turbogenerator and the steam generator in good conditions of exploitation; andthat another block, the No.7, presented many mandatory out of service product of an insufficient repair of its generator.This situation lead to analyze the possibility of

  15. Estudio numérico y experimental de fenómenos hidrodinámicos que ocurren en bombas centrífugas como turbinas

    OpenAIRE

    Tobón Espinosa, Daniel Felipe

    2016-01-01

    La tendencia mundial de administrar y operar a distancia las centrales hidroeléctricas está obligando a los expertos a replantear los estrategias de monitoreo y diagnóstico de sus máquinas -- Esto ha conducido también, a reducir el personal experto que reside in-situ y que se encarga de operar y mantener los sistemas técnicos, y además de atender cualquier eventualidad que pueda ocurrir -- Por eso, desde hace ya varios años se han venido desarrollando sistemas expertos que puedan suplir las d...

  16. Thermo mechanical analysis and optimization in transient state of the first stage of blades in a gas turbine with internal cooling; Analisis y optimizacion termomecanica, en estado transitorio, de la primera etapa de alabes en una turbina de gas con enfriamiento interno

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso

    2007-04-15

    ). This interface allows integrating the computational models virtually, although they have different grids, and that the CFD model registers the data in center cells, whereas the FEA model registers them in the nodes. Pressure, temperature and velocity profiles were obtained for the fluid and, temperature and stress for the solid. The obtained results are compared with experimental data reported in literature obtaining acceptable results. With this work, information for complementary studies is generated, as failure analysis faults and blade life assessment. [Spanish] Este trabajo presenta una metodologia para el analisis termomecanico de un alabe de turbina de gas con enfriamiento interno, la cual permite eliminar simplificaciones tipicas en este tipo de estudios, tales como: analisis ensamblados de perfiles bidimensionales, que desprecia los efectos tridimensionales del flujo que rodea la punta del alabe entre otras zonas; uso de coeficientes de transferencia de calor semi-empiricos obtenidos de predicciones de flujo adiabatico, entre otros. Esta metodologia utiliza dinamica de fluidos computacional ((CFD) por sus siglas en ingles) para el analisis de flujo y transferencia de calor conjugado y, analisis por elementos finitos ((FEA) por sus siglas en ingles) para el analisis termoestructural, estas tecnicas de simulacion han llegado a ser herramientas estandar para cada uno de los analisis, pero su integracion virtual aun esta en proceso de desarrollo. El codigo de CFD utiliza las ecuaciones de conservacion, asi como ecuaciones constitutivas adicionales para los diversos fenomenos que se presentan, permitiendo utilizar funciones definidas por el usuario para utilizar condiciones de frontera dinamicas en el analisis transitorio y propiedades variables de los materiales, lo cual incrementa la presion de las predicciones. Para resolver las ecuaciones y encontrar una solucion aproximada, se utiliza el metodo de volumen finito. Por otro lado, el codigo de FEA utiliza las

  17. Overview of chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

    1993-06-01

    Chemical vapor infiltration (CVI) is developing into a commercially important method for the fabrication of continuous filament ceramic composites. Current efforts are focused on the development of an improved understanding of the various processes in CVI and its modeling. New approaches to CVI are being explored, including pressure pulse infiltration and microwave heating. Material development is also proceeding with emphasis on improving the oxidation resistance of the interfacial layer between the fiber and matrix. This paper briefly reviews these subjects, indicating the current state of the science and technology.

  18. A Lithium Vapor Box Divertor Similarity Experiment

    Science.gov (United States)

    Cohen, Robert A.; Emdee, Eric D.; Goldston, Robert J.; Jaworski, Michael A.; Schwartz, Jacob A.

    2017-10-01

    A lithium vapor box divertor offers an alternate means of managing the extreme power density of divertor plasmas by leveraging gaseous lithium to volumetrically extract power. The vapor box divertor is a baffled slot with liquid lithium coated walls held at temperatures which increase toward the divertor floor. The resulting vapor pressure differential drives gaseous lithium from hotter chambers into cooler ones, where the lithium condenses and returns. A similarity experiment was devised to investigate the advantages offered by a vapor box divertor design. We discuss the design, construction, and early findings of the vapor box divertor experiment including vapor can construction, power transfer calculations, joint integrity tests, and thermocouple data logging. Heat redistribution of an incident plasma-based heat flux from a typical linear plasma device is also presented. This work supported by DOE Contract No. DE-AC02-09CH11466 and The Princeton Environmental Institute.

  19. Droplet Vaporization in a Supercritical Microgravity Environment

    Science.gov (United States)

    Curtis, E. W.; Farrell, P. V.

    1987-01-01

    A model is presented which describes single liquid droplet vaporization at nearly critical liquid pressures and temperatures. A modified Redlich-Kwong equation of state is used to evaluate the fugacities and liquid and vapor mole fractions at the interface under the assumption of interface equilibrium. Results obtained for different droplet sizes and conditions indicate significant differences in behavior in comparison with low-pressure quasi-steady droplet vaporization.

  20. Vapor Pressure Data Analysis and Statistics

    Science.gov (United States)

    2016-12-01

    there were flaws in the original data prior to its publication. 3. FITTING METHODS Our process for correlating experimental vapor pressure ...2. Penski, E.C. Vapor Pressure Data Analysis Methodology, Statistics, and Applications; CRDEC-TR-386; U.S. Army Chemical Research, Development, and... Chemical Biological Center: Aberdeen Proving Ground, MD, 2006; UNCLASSIFIED Report (ADA447993). 11. Kemme, H.R.; Kreps, S.I. Vapor Pressure of

  1. Evaluation of a process for the removal of gases contained in geothermal steam through condensation and re-evaporation; Evaluacion de un proceso de remocion de gases contenidos en el vapor geotermico, por medio de la condensacion y de revaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Angulo C, Raul; Lam Rea, Luis; Garmino, Hector; Jimenez, Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    The Cerro Prieto I Geothermal Field, developed and operated by the Comision Federal de Electricidad (CFE), has currently an installed electric power generation capacity of 180 MW and is at a very advanced stage in the development of Cerro Prieto II and III, which will allow to raise the generation capacity to 620 MW. During the exploitation of a geothermal field, in producing steam with the purpose of generating electricity, brines and waste gases are obtained. The hydrogen sulfide exhaust to the environment implies pollution problems, for this reason processes have been developed for the oxidation of these gases downstream the turbogenerator either in the flow of separated gases in the steam condensation or in the condensate produced. The Instituto de Investigaciones Electricas (IIE) has collaborated with CFE in the evaluation of the environmental impact of this gas and in the development of the processes for its abatement. [Espanol] El campo geotermico de Cerro Prieto I, desarrollado y operado por la Comision Federal de Electricidad (CFE), actualmente tiene una capacidad instalada de generacion de energia electrica de 180 MW, y se encuentra en etapa muy avanzada, el desarrollo de Cerro Prieto II y III, lo que permitira incrementar la capacidad de generacion a 620 MW. Durante la explotacion de un campo geotermico, al producir vapor con el proposito de generar electricidad, se obtienen salmueras y gases de desecho. La descarga de acido sulfhidrico a la atmosfera implica problemas de contaminacion, por esta razon se han desarrollado procesos para la oxidacion de este gas aguas abajo de la turbina generadora, ya sea en la corriente de gases que se separan en la condensacion del vapor o en el condensado producido. El Instituto de Investigaciones Electricas (IIE) ha colaborado con la CFE en la evaluacion del impacto ambiental de este gas y en el desarrollo de sus procesos de abatimiento.

  2. Mars water vapor, near-surface

    Science.gov (United States)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.

    1982-01-01

    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  3. Recubrimientos protectores para componentes de turbinas de aviación y de generación de energía depositados por proyección por plasma

    Directory of Open Access Journals (Sweden)

    Agüero Bruna, A.

    2000-08-01

    Full Text Available Coatings produced by aluminium diffusion, called aluminide are employed to increase the oxidation and corrosion resistance, increasing the life of Ni and Co base superalloys components at temperatures comprised between 900 and 1050ºC. Consequently these coatings are frequently employed in aeronautic and power generation turbines as well as in the chemical industry. Aluminides are industrially produced by pack cementation or CVD and recently it has been demonstrated that its resistance significantly increases when Cr is added (chrome-aluminides. During this work, a feasibility study has been carried out in order to determine if plasma spray can be employed for depositing this type of coatings on turbine blades. Therefore, aluminium and aluminium/chromium layers were deposited on Ni base IN100 superalloy specimens that were subsequently subjected to a diffusion heat treatment under Ar flow. Characterisation and analysis of the coatings were carried out by metallography , SEM and EDS. Cyclic oxidation tests were carried out at 1050º C while molten sulphate hot corrosion was performed at 900º C. The results of this preliminary study are promising and indicate that plasma spray can be developed as an industrial process for production of aluminide and chrome-aluminide coatings.

    Los recubrimientos producidos por difusión de aluminio, llamados aluminuros, se emplean para aumentar la resistencia a la oxidación y a la corrosión, incrementando la vida de componentes fabricados con superaleaciones de níquel y cobalto a temperaturas comprendidas entre 900 y 1050º C. Por ello se emplean muy frecuentemente en turbinas aeronaúticas y de producción de energía y en la industria química. Los aluminuros se obtienen industrialmente mediante cementación o CVD y recientemente se ha demostrado que su resistencia aumenta significativamente cuando se añade cromo (cromoaluminuros. Durante el presente trabajo, se ha realizado un estudio de viabilidad

  4. Avaliação técnica de um aspersor canhão do tipo turbina Technical evaluation of a gun sprinkler of the turbine type

    Directory of Open Access Journals (Sweden)

    Júlio H. Fernandes César

    2004-08-01

    Full Text Available Objetivou-se com este trabalho avaliar o desempenho técnico do aspersor canhão do tipo turbina, modelo "Mercury", fabricado pela Società Hidromecânica Emiliana (SIME na Itália e importado pela indústria Metal Lavras Ltda. Para este estudo, foram testados três bocais ( 16, 20 e 22 mm, com pressões de serviço de 250, 300, 350, 400, 450 e 500 kPa, pelo método de ensaio radial, com a finalidade de verificar a influência dessas variáveis na uniformidade de distribuição, intensidade de aplicação, diâmetro médio das gotas, raio de alcance e uniformidade de rotação. Tabelas contendo os valores de intensidade média de precipitação, espaçamentos recomendados e coeficientes de uniformidade foram criadas, cobrindo uma deficiência demonstrada no catálogo do fabricante. Observou-se que o diâmetro médio das gotas aumentou à medida que se reduziu a pressão de serviço, e o comportamento do mesmo não se adapta ao modelo clássico de aumento gradual do diâmetro médio das gotas, pois foram constatados vários diâmetros de gotas ao longo do raio molhado. A equação potencial ajustou-se bem aos dados de vazão versus pressão, e o bocal 16 mm mostrou-se mais susceptível às variações de pressão de serviço. O perfil de distribuição demonstrado é do tipo "doughnut" e retangular. Os dados de uniformidade de rotação demonstraram a eficiência do sistema de rotação do tipo turbina. Pelas tabelas geradas, recomenda-se o uso delas em substituição ao catálogo do fabricante.This work intended to evaluate the technical performance of a gun sprinkler of the type turbine model "Mercury" manufactured by Società Hidromecânica Emiliana (SIME in Italy and imported by the Brazilian company Metal Lavras Ltda. The study was developed with three nozzles (16, 20 and 22 mm, with service pressures of 250, 300, 350, 400, 450 and 500 kPa by the radial method test, with the purpose of verifying the influence of these parameters on

  5. Estudio de factibilidad para la generación eléctrica alternativa utilizando turbinas de río en la Isla Santay

    OpenAIRE

    Tenén Juca, Wilmer Adrián; Trujillo Zamora, José Vicente

    2007-01-01

    Hoy en día se habla mucho de la contaminación ambiental y de los grandes problemas que esta ocasiona, problemas muy serios como el calentamiento global que afecta a todo el planeta y una de las causas principales de este problema, es la emisión de CO2 tanto por automóviles, fabricas como por parte de centrales térmicas de generación eléctrica, muy necesarias en nuestro medio para cumplir con la demanda diaria del país, sin olvidar la erosión del suelo y el daño de la fauna por parte de las ce...

  6. Las aguas termominerales de Tabio

    Directory of Open Access Journals (Sweden)

    Antonio María Barriga Villalba

    1933-01-01

    Full Text Available La pintoresca población de Tabio, situada en el vallecito que forman dos repliegues de la gran cordillera montañosa que rodea la sabana de Bogotá, es un pueblecito apacible, famoso desde tiempo inmemorial por las aguas termales que brotan en la falda de los cerros situados al occidente, a unos mil metros de la iglesia de la población, en terrenos de propiedad del doctor Pompilio Martínez. Fue fundada Tabio en el año 1761 (*. Se halla a 4°50'50" de latitud norte y 0° 04'00" de longitud del meridiano de Bogotá. Clima seco en la mayor parte del año, temperatura media 14°.5 C. Presión atmosférica 560 mm.; altura sobre el nivel del mar 2.650 metros; temperatura de. ebullición del agua 91°.62 C.; humedad en vapor de agua, por metro cúbico, en los días secos 127,5 gramos por metro cúbico; en los días húmedos, 251,8 gramos por metro cúbico. En el sitio de las fuentes la humedad relativa media es de 38.38 por 100 y la temperatura de la atmósfera varía de 10° C. hasta 23°C.; en los días de sol, hacia las doce del día, la temperatura de la atmósfera cerca de las fuentes es de 20°-22°C.

  7. Mesh sensitivity in the thermal analysis of a gas turbine a blade with internal cooling; Sensibilidad de malla en el analisis termico de un alabe de turbina de gas con enfriamiento interno

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro Ayala, Jorge Arturo; Gallegos Munoz, Armando [Facultad de Ingenieria Mecanica, Electrica y Electronica (FIMEE), Universidad de Guanajuato (Mexico); Campos Amezcua, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    This article presents the methodology to generate the mesh model of the computer model of a blade by means of commands in the software of CFD Fluent, mainly in the fluid zone, since a mesh sensitivity analysis becomes too expensive in terms of human and computer resources. When geometry is too irregular, modifications are required in the mesh to avoid problems such as the divergence, instability in the solution and the dependency on the results of temperature, pressure, velocity, etc. Such is the case of a blade with internal cooling of the first stage of a gas turbine. The results are included of the generated mesh as well as of the thermal analysis of the blade. Additionally the results of temperature, pressure and velocity of the combustion gases and of the cooling air are shown. [Spanish] Este articulo presenta la metodologia para generar el mallado del modelo computacional de un alabe por medio de comandos en el software de CFD Fluent, principalmente en la zona del fluido, ya que un analisis de sensibilidad de malla se vuelve demasiado costoso en terminos de recursos humanos y computacionales. Cuando la geometria es demasiado irregular, se requiere de modificaciones en la malla para evitar problemas como son la divergencia, inestabilidad en la solucion y la dependencia de los resultados de temperatura, presion, velocidad, etc. Tal es el caso de un alabe con enfriamiento interno de la primera etapa de una turbina de gas. Se incluyen los resultados tanto de la malla generada como del analisis termico del alabe. Adicionalmente se muestran los resultados de temperatura, presion y velocidad de los gases de la combustion y del aire de enfriamiento.

  8. Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

    Directory of Open Access Journals (Sweden)

    Dora M. Paolucci

    2011-03-01

    Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

  9. LNG fire and vapor control system technologies

    Energy Technology Data Exchange (ETDEWEB)

    Konzek, G.J.; Yasutake, K.M.; Franklin, A.L.

    1982-06-01

    This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and vapor control systems. In this report a brief summary of LNG physical properties is given. This is followed by a discussion of basic fire and vapor control design philosophy and detailed reviews of fire and vapor control practices. The operating characteristics and typical applications and application limitations of leak detectors, fire detectors, dikes, coatings, closed circuit television, communication systems, dry chemicals, water, high expansion foam, carbon dioxide and halogenated hydrocarbons are described. Summary descriptions of a representative LNG peakshaving facility and import terminal are included in this report together with typical fire and vapor control systems and their locations in these types of facilities. This state-of-the-art review identifies large differences in the application of fire and vapor control systems throughout the LNG industry.

  10. Mechanics of gas-vapor bubbles

    NARCIS (Netherlands)

    Hao, Yue; Zhang, Yuhang; Prosperetti, Andrea

    2017-01-01

    Most bubbles contain a mixture of vapor and incondensible gases. While the limit cases of pure vapor and pure gas bubbles are well studied, much less is known about the more realistic case of a mixture. The bubble contents continuously change due to the combined effects of evaporation and

  11. Condensation of vapor bubble in subcooled pool

    Science.gov (United States)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

    2017-02-01

    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  12. Vapor Pressures of Several Commercially Used Alkanolamines

    NARCIS (Netherlands)

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

  13. Soil vapor extraction with dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, N.R. [Univ. of Waterloo, Ontario (Canada)

    1996-08-01

    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  14. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  15. Logical model for the control of a BWR turbine;Modelo logico para el control de una turbina de un BWR

    Energy Technology Data Exchange (ETDEWEB)

    Vargas O, Y. [Universidad del Valle de Mexico, Campus Toluca, Av. Las Palmas No. 136, Col. San Jorge Pueblo Nuevo, 52140 Metepec, Estado de Mexico (Mexico); Amador G, R.; Ortiz V, J.; Castillo D, R., E-mail: yonaeton@hotmail.co [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2009-07-01

    In this work a design of a logical model is presented for the turbine control of a nuclear power plant with a BWR like energy source. The model is sought to implement later on inside the thermal hydraulics code of better estimate RELAP/SCDAPSIM. The logical model is developed for the control and protection of the turbine, and the consequent protection to the BWR, considering that the turbine control will be been able to use for one or several turbines in series. The quality of the present design of the logical model of the turbine control is that it considers the most important parameters in the operation of a turbine, besides that they have incorporated to the logical model the secondary parameters that will be activated originally as true when the turbine model is substituted by a detailed model. The development of the logical model of a turbine will be of utility in the short and medium term to carry out analysis on the turbine operation with different operation conditions, of vapor extraction, specific steps of the turbine to feed other equipment s, in addition to analyze the separate and the integrated effect. (Author)

  16. EFECTOS DE LOS GASES PRODUCTO DE LA COMBUSTIÓN EN LOS GENERADORES DE VAPOR

    Directory of Open Access Journals (Sweden)

    Manuel Plá Duporté

    2011-02-01

    Full Text Available En el trabajo se presentan recopilados, los efectos de ensuciamiento y corrosión que provocan en ungenerador de vapor acuotubular los gases productos de la combustión de combustibles líquidos,explicándose los mecanismos mediante los cuales ocurren tanto en las zonas de alta temperaturacomo en las de baja temperatura  This paper presents gathering of the dirty and corrosion effects of flue gas from liquid fuels, also it’sexplained the process by means of which happen in high and low temperature surfaces in steam watergenerator

  17. Synthesis of carbon nanomaterials by catalytic chemical vapor deposition: growth mechanisms on metal powders and foils

    OpenAIRE

    Romero Rodríguez, Pablo

    2017-01-01

    Actualmente, las excelentes propiedades proporcionadas a escala nanométrica por los nanomateriales de carbono, como nanotubos y grafeno, motivan la propuesta teórica de un gran número de aplicaciones. Estos nanomateriales se pueden producir por deposición química en fase vapor (CVD), que consiste en la descomposición térmica de hidrocarburos sobre catalizadores metálicos. La técnica de CVD permite, a través del control de las condiciones de síntesis y la composición y morfología del catalizad...

  18. Vaporization of perfluorocarbon droplets using optical irradiation.

    Science.gov (United States)

    Strohm, Eric; Rui, Min; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael

    2011-06-01

    Micron-sized liquid perfluorocarbon (PFC) droplets are currently being investigated as activatable agents for medical imaging and cancer therapy. After injection into the bloodstream, superheated PFC droplets can be vaporized to a gas phase for ultrasound imaging, or for cancer therapy via targeted drug delivery and vessel occlusion. Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization using a method we term optical droplet vaporization (ODV). In order to facilitate ODV of PFC droplets which have negligible absorption in the infrared spectrum, optical absorbing nanoparticles were incorporated into the droplet. In this study, micron-sized PFC droplets loaded with silica-coated lead sulfide (PbS) nanoparticles were evaluated using a 1064 nm laser and ultra-high frequency photoacoustic ultrasound (at 200 and 375 MHz). The photoacoustic response was proportional to nanoparticle loading and successful optical droplet vaporization of individual PFC droplets was confirmed using photoacoustic, acoustic, and optical measurements. A minimum laser fluence of 1.4 J/cm(2) was required to vaporize the droplets. The vaporization of PFC droplets via laser irradiation can lead to the activation of PFC agents in tissues previously not accessible using standard ultrasound-based techniques.

  19. Water Vapor Permeation in Plastics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-01-01

    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  20. Vapor Cavitation in Dynamically Loaded Journal Bearings

    Science.gov (United States)

    Jacobson, B. O.; Hamrock, B. J.

    1983-01-01

    High speed motion camera experiments were performed on dynamically loaded journal bearings. The length to diameter ratio of the bearing, the speed of the roller and the tube, the surface material of the roller, and the static and dynamic eccentricity of the bearing were varied. One hundred and thirty-four cases were filmed. The occurrence of vapor cavitation was clearly evident in the films and figures presented. Vapor cavitation was found to occur when the tensile stress applied to the oil exceeded the tensile strength of the oil or the binding of the oil to the surface. The physical situation in which vapor cavitation occurs is during the squeezing and sliding motion within a bearing. Besides being able to accurately capture the vapor cavitation on film, an analysis of the formation and collapse of the cavitation bubbles and characteristics of the bubble content are presented.

  1. External fuel vaporization study, phase 1

    Science.gov (United States)

    Szetela, E. J.; Chiappetta, L.

    1980-01-01

    A conceptual design study was conducted to devise and evaluate techniques for the external vaporization of fuel for use in an aircraft gas turbine with characteristics similar to the Energy Efficient Engine (E(3)). Three vaporizer concepts were selected and they were analyzed from the standpoint of fuel thermal stability, integration of the vaporizer system into the aircraft engine, engine and vaporizer dynamic response, startup and altitude restart, engine performance, control requirements, safety, and maintenance. One of the concepts was found to improve the performance of the baseline E(3) engine without seriously compromising engine startup and power change response. Increased maintenance is required because of the need for frequent pyrolytic cleaning of the surfaces in contact with hot fuel.

  2. Impact vaporization: Late time phenomena from experiments

    Science.gov (United States)

    Schultz, P. H.; Gault, D. E.

    1987-01-01

    While simple airflow produced by the outward movement of the ejecta curtain can be scaled to large dimensions, the interaction between an impact-vaporized component and the ejecta curtain is more complicated. The goal of these experiments was to examine such interaction in a real system involving crater growth, ejection of material, two phased mixtures of gas and dust, and strong pressure gradients. The results will be complemented by theoretical studies at laboratory scales in order to separate the various parameters for planetary scale processes. These experiments prompt, however, the following conclusions that may have relevance at broader scales. First, under near vacuum or low atmospheric pressures, an expanding vapor cloud scours the surrounding surface in advance of arriving ejecta. Second, the effect of early-time vaporization is relatively unimportant at late-times. Third, the overpressure created within the crater cavity by significant vaporization results in increased cratering efficiency and larger aspect ratios.

  3. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  4. Water Vapor Corrosion in EBC Constituent Materials

    Science.gov (United States)

    Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.

    2017-01-01

    Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.

  5. Static Water Vapor Feed Electrolyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  6. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products from the GOES-8 satellite spanning the 1987-1988 El Nino...

  7. Indoor Air Vapor Intrusion Mitigation Approaches

    Science.gov (United States)

    The National Risk Management Research Laboratory has developed a technology transfer document regarding management and treatment of vapor intrusion into building structures. This document describes the range of mitigation technologies available.

  8. Arctic Water Vapor Characteristics from Rawinsondes

    Data.gov (United States)

    National Aeronautics and Space Administration — A gridded climatological monthly-mean data base of Arctic water vapor characteristics has been assembled by combining fixed station data with data from soundings...

  9. Pressure fluctuations on the bed of surge tank at the H.P. Zimapan, Hgo., with different arrangements studied on hydraulic model, with the lowest operation conditions; Fluctuaciones de presion en la base del pozo de oscilacion del P.H. Zimapan Hgo., con diferentes arreglos estudiados en modelo hidraulico ante las condiciones minimas de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Marengo Mogollon, H. [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico (Mexico)]. E-mail: humberto.marengo@cfe.gob.mx; Ochoa Alvarez, F.J.; Cortes Cortes, C. [Comision Federal de Electricidad (Mexico)]. E-mail: federico.ochoa@cfe.gob.mx; carlos.cortes01@cfe.gob.mx

    2009-10-15

    In this paper, the pressure fluctuations of the surge tank in the Zimapan Hydroelectric Project are compared in a hydraulic model. The shaft is located lateral, over the conduction tunnel and in the simple form (permitting the tunnel entering the shaft); with and without orifice plates taking into account the demand and supply condition of energy with the minimum level of water of the conduction. It was determined the hydraulic efficiency and it was found that it was the best constructive option. [Spanish] En este articulo se comparan las fluctuaciones de presion en el pozo de oscilacion del P.H. Zimapan, Hgo., Mexico las cuales fueron estudiadas en modelo hidraulico al considerar dicho pozo ubicado en diferentes posiciones; lateralmente y sobre el eje de la conduccion; pozo simple y con tuberia de conexion; con y sin placa de orificio, para maniobras de rechazo y demanda de carga de las turbinas de generacion con el nivel del agua correspondiente al NAMINO. Se determino la eficiencia hidraulica comparandola con las otras opciones encontrandose que la mejor opcion para el funcionamiento hidraulico es el pozo lateral, que ademas permite optimizar el procedimiento constructivo.

  10. Vapor phase transformer drying – Part II

    OpenAIRE

    Steeves, Gregory R.

    2016-01-01

    Vapor phase drying is the most effective method for drying transformer insulation in a manufacturing setting. The process does not lend itself well to transformer drying in the field for a variety of reasons, including the difficulty of removing residual kerosene which can cause a potential change in transformer oil flash point. Several techniques are available for transformer insulation drying in both the field and in manufacturing. Vapor phase drying as part of transformer manufacturing is ...

  11. Vapor phase transformer drying – Part I

    OpenAIRE

    Steeves, Gregory R.

    2016-01-01

    Vapor phase drying is the most effective method for drying transformer insulation in a manufacturing setting. The process does not lend itself well to transformer drying in the field for a variety of reasons, including the difficulty of removing residual kerosene which can cause a potential change in transformer oil flash point. Several techniques are available for transformer insulation drying in both the field and in manufacturing. Vapor phase drying as part of transformer manufacturing is ...

  12. Volatiles and Exsolved Vapor in Volcanic Systems

    OpenAIRE

    Edmonds, Marie; Wallace, PJ

    2017-01-01

    The role of volatiles in magma dynamics and eruption style is fundamental. Magmatic volatiles partition between melt, crystal, and vapor phases and, in so doing, change magma properties. This has consequences for magma buoyancy and phase equilibria. An exsolved vapor phase, which may be distributed unevenly through reservoirs, contains sulfur and metals that are either transported into the atmosphere or into ore deposits. This article reviews the controls on volatile solubility and the method...

  13. Vapor-Induced Phase Transformations in Docetaxel

    OpenAIRE

    Tatini, Lakshmi Kumar; Krishna Reddy, K. V. S. R.; Someswara Rao, N.

    2012-01-01

    Vapor-induced transformations of docetaxel anhydrous (form DA) under ambient conditions have been studied using methanol, ethanol, and water as the solvent media. The online vapor-induced transformations were monitored by powder X-ray diffractometry. New solid forms (solvates/hydrates/anhydrous) of docetaxel anhydrous were obtained in stoichiometric ratios which were characterized completely using powder X-ray diffraction, differential scanning calorimeter, thermogravimetric analysis, and spe...

  14. Optical monitor for water vapor concentration

    Science.gov (United States)

    Kebabian, Paul

    1998-01-01

    A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

  15. Bioeffects due to acoustic droplet vaporization

    Science.gov (United States)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  16. Vapor phase lubrication of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hanyaloglu, B.F.; Graham, E.E.; Oreskovic, T.; Hajj, C.G. [Cleveland State Univ., OH (United States)

    1995-06-01

    In a previous study, it was found that when a nickel-based superalloy IN750 was heated to high temperatures, a passive layer of aluminum oxide formed on the surface, preventing vapor phase lubrication. In this study, two nickel-chrome-iron alloys and a nickel-copper alloy were studied for high temperature lubrication to see if these alloys, which contained small amounts of aluminum, would exhibit similar behavior. It was found that under static conditions, all three alloys formed a lubricious nodular coating when exposed to a vapor of aryl phosphate. Under dynamic sliding conditions at 500{degrees}C, these alloys were successfully lubricated with a coefficient of friction of 0.1 and no detectable wear. In order to explain these results, a direct correlation between successful vapor phase lubrication and the composition of the alloys containing aluminum has been proposed. If the ratio of copper/aluminum or iron/aluminum is greater that 100 vapor phase, lubrication will be successful. If the ratio is less than 10, a passive aluminum oxide layer will prevent vapor phase lubrication. By selecting alloys with a high iron or copper content, vapor phase lubrication can provide excellent lubrication at high temperatures. 14 refs., 11 figs., 1 tab.

  17. Methodology for energy diagnosis in distribution steam lines; Metodologia para diagnostico de energia en lineas de distribucion de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Almanza, M.; Ambriz, J. J.; Romero P, H. [Universidad Autonoma Metropolitana Iztapalapa, Mexico, D. F. (Mexico)

    1992-12-31

    This paper shows a methodology that results of great advantage in the development of the energy analysis of an industrial facility that utilizes steam as a mean of energy transport and where the steam operated equipment is physically located in a remote place, away from the generation site. Mention is made here of the equipment characteristics that can be used for such purpose, the most important parameters to identify in a rapid and efficient way the faults presented in the steam distribution system in the industrial plants and the formats that contribute to keep the corresponding records for efficiently maintain in operation the steam pipeline net in conjunction with the involved accessories. [Espanol] En el presenta trabajo se muestra una metodologia que resulta de gran utilidad en el desarrollo del analisis energetico de una planta industrial, en la cual se emplee el vapor como medio de transporte de la energia y en donde el equipo que utiliza el vapor se encuentre fisicamente en un lugar apartado de la zona de generacion. Aqui se mencionan las caracteristicas del equipo que se puede utilizar para dicho diagnostico, los parametros de mayor importancia para identificar en forma rapida y eficiente las fallas que se presentan en el sistema de distribucion de vapor en las plantas industriales y los formatos que contribuyen a llevar los registros correspondientes para mantener operando eficientemente la red de vapor, en conjunto con los accesorios que en ella se involucran.

  18. Metal vapor condensation under high pressure (mercury vapor to 500 psia). [Heat transfer coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, S.; Bonilla, C.F.

    1975-01-01

    Mercury vapor up to 500 psia was condensed outside a cylindrical tube in both horizontal and vertical positions. Results show consistently low heat transfer coefficients compared to Nusselt's theory. Two auxiliary mercury vapor condensers downstream of the boiler vent were used to control and safeguard the system. Constantan wires were spot welded on the surface inside the test condenser tube. The heat flux ranged from 20,000 to 45,000 Btu/h-ft/sup 2/ and the temperature differences between vapor and condensing wall from 6 to 50/sup 0/F. The condensation heat transfer coefficients, ranging from 850 to 3,500 Btu/h-/sup 0/F-ft/sup 2/, are only about 3 to 9 percent of those predicted by Nusselt's theory. Due to the positive pressure in the system for most test runs, the chance of any in-leakage of noncondensable gases into the boiler is extremely small. Since no substantial change of heat transfer rate resulted from wide variations in the heat load on the reflux condenser at some specific heat flux on the test condenser tube, the low heat transfer rate of mercury vapor condensation was not due to the presence of any non-condensable gas. The test data for high vapor pressure up to 500 psia reveal that the heat transfer coefficient is independent of the vapor pressure level. The condensation coefficients calculated based on kinetic theory are much smaller than unity and decreasewith vapor pressure. It is hypothesized that dimer content in the metal vapor phase might behave as non-condensable or semi-condensable gas and create a diffusional barrier at the vapor-liquid interface near the condensate film. This dimer vapor could be the main cause of interfacial resistance during metal vapor condensation process. 41 figures, 7 tables, 58 references. (DLC)

  19. Análisis de pequeña señal de sistemas de regulación de velocidad y turbinas hidroeléctricas de generadores sincrónicos utilizando el programa computacional DIgSILENT Power Factory

    OpenAIRE

    Cevallos Pasquel, Benigno Rafael

    2014-01-01

    El presente trabajo se enfoca en el análisis de pequeña señal de los sistemas de regulación de velocidad y turbinas hidráulicas y su influencia en el mejoramiento de la estabilidad de un sistema eléctrico de potencia. Se establece una metodología de sintonización de los reguladores de velocidad para centrales hidroeléctricas, ya sea para funcionamiento en modo aislado o en modo de operación integrada a un sistema de potencia. En el estudio de pequeña señal se modela un regulador de velocidad ...

  20. Las tics en las administraciones municipales

    OpenAIRE

    Ballesteros, Anais; Zapatería, Mónica L.

    2007-01-01

    El presente Informe da cuenta, sintéticamente, del uso y apropiación de las TICs en la Comuna de Ensenada como parte de las indagaciones generadas en el proyecto de Investigación: Usos sociopolíticos de las Tecnologías de Comunicación e Información (TICs) de la Sociedad de la Información (SI) aplicadas en los procesos políticos locales. Estudio de casos en la Región Capital: municipios de La Plata, Berisso y Ensenada, que se desarrolla en la Facultad de Periodismo y Comunicación Soc...

  1. Determination of Cannabinoid Vapor Pressures to Aid in Vapor Phase Detection of Intoxication.

    Science.gov (United States)

    Lovestead, Tara M; Bruno, Thomas J

    2017-09-01

    The quest for a reliable means to detect cannabis intoxication with a breathalyzer is ongoing. To design such a device, it is important to understand the fundamental thermodynamics of the compounds of interest. The vapor pressures of two important cannabinoids, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC), are presented, as well as the predicted normal boiling temperature (NBT) and the predicted critical constants (these predictions are dependent on the vapor pressure data). The critical constants are typically necessary to develop an equation of state (EOS). EOS-based models can provide estimations of thermophysical properties for compounds to aid in designing processes and devices. An ultra-sensitive, quantitative, trace dynamic headspace analysis sampling called porous layered open tubular-cryoadsorption (PLOT-cryo) was used to measure vapor pressures of these compounds. PLOT-cryo affords short experiment durations compared to more traditional techniques for vapor pressure determination (minutes versus days). Additionally, PLOT-cryo has the inherent ability to stabilize labile solutes because collection is done at reduced temperature. The measured vapor pressures are approximately 2 orders of magnitude lower than those measured for n-eicosane, which has a similar molecular mass. Thus, the difference in polarity of these molecules must be impacting the vapor pressure dramatically. The vapor pressure measurements are presented in the form of Clausius-Clapeyron (or van't Hoff) equation plots. The predicted vapor pressures that would be expected at near ambient conditions (25 °C) are also presented.

  2. Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

    Science.gov (United States)

    The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampl...

  3. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Abstract Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture distribution. The van Genuchten relations can be used for describing the soil moisture retention curve, and give results consistent with the results from a previous experimental study. Other modeling methods that account for soil moisture are evaluated. These modeling results are also compared with the measured subsurface concentration profiles in the U.S. EPA vapor intrusion database. PMID:24170970

  4. Vapor scavenging by atmospheric aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, E.

    1996-05-01

    Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

  5. A Review of Vapor Intrusion Models

    Science.gov (United States)

    Yao, Yijun; Suuberg, Eric M.

    2013-01-01

    A complete vapor intrusion (VI) model, describing vapor entry of volatile organic chemicals (VOCs) into buildings located on contaminated sites, generally consists of two main parts-one describing vapor transport in the soil and the other its entry into the building. Modeling the soil vapor transport part involves either analytically or numerically solving the equations of vapor advection and diffusion in the subsurface. Contaminant biodegradation must often also be included in this simulation, and can increase the difficulty of obtaining a solution, especially when explicitly considering coupled oxygen transport and consumption. The models of contaminant building entry pathway are often coupled to calculations of indoor air contaminant concentration, and both are influenced by building construction and operational features. The description of entry pathway involves consideration of building foundation characteristics, while calculation of indoor air contaminant levels requires characterization of building enclosed space and air exchange within this. This review summarizes existing VI models, and discusses the limits of current screening tools commonly used in this field. PMID:23360069

  6. Thermodynamics and Kinetics of Silicate Vaporization

    Science.gov (United States)

    Jacobson, Nathan S.; Costa, Gustavo C. C.

    2015-01-01

    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  7. Aceros sinterizados tratados al vapor para la fabricación de componentes de amortiguadores bitubo

    Directory of Open Access Journals (Sweden)

    Cambronero, L. E. G.

    2000-06-01

    Full Text Available In this work, properties of three sintered and steam treated alloyed irons were analysed. These materials were Fe+2Cu, Fe+0.6C+0.5Cu, and Fe+0.45P+2.5Cu, which were obtained by powder mixing. Once pressed and sintered, samples were steam treated (surface treatment which is characteristic of sintered irons. Density, hardness and tensile strength were obtained on sintered and steam treated samples, within their microstructure analysis. Also, a tribological study was carried out since some parts of shock absorbers are working under friction.

    En este trabajo se analizan las propiedades de tres hierros aleados sintetizados y tratados al vapor. Los materiales seleccionados son el Fe+2Cu, Fe+0.6C+0.5Cu, y Fe+0.45P+2.5Cu, obtenidos por mezcla elemental de polvos. Una vez compactados y sintetizados, se sometieron a un tratamiento de recubrimiento característico de los hierros, como es el tratamiento al vapor. En los materiales sintetizados y tratados al vapor, se determinaron su densidad, dureza y resistencia a tracción, junto con su análisis microestructural. Así mismo dado que algunos de los componentes de los amortiguadores bitubo están sometidos a esfuerzos de fricción, se analizaron el comportamiento tribologíco de los materiales obtenidos tanto en estado sintetizado como tratados al vapor.

  8. Vaporization of droplets in premixing chambers

    Science.gov (United States)

    Yule, A. J.; Chigier, N. A.

    1980-01-01

    Detailed measurements were made of the structures of turbulent fuel sprays vaporizing in heated airstreams. The measurements show the size dependent vaporization and dispersion of the droplets and the important influence of the large eddies in the turbulence. The measurements form a data base for the development of models of fuel spray vaporization. Two laser techniques were specially developed for the investigation. A laser tomography technique converts line-of-sight light scattering measurements into time averaged 'point' measurements of droplet size distribution and volume concentration. A laser anemometer particle sizing technique was further developed to permit accurate measurements of individual particle sizes and velocities, with backscatter collection of light. The experiments are combined with heat transfer models to analyze the performance of miniature thermocouples in liquid sprays.

  9. Tolman's length and limiting supersaturation of vapor

    Science.gov (United States)

    Alekseechkin, Nikolay V.

    2018-01-01

    The classical Kelvin formula for the equilibrium vapor pressure over a droplet of radius R is extended to small radii and vapor non-ideality, from where the limiting supersaturation condition is obtained by relating the point R = 0 to the value of limiting (spinodal) supersaturation of vapor. The analysis of different dependences of the Tolman length on radius, δ (R) , obeying this condition suggests that (i) the value of δ (0) is positive and the function δ (R) decreases with increasing radius; (ii) the curvature effect (the dependence of surface tension on radius) in the nucleation region is determined by the value of δ (0) . At the same time, this effect is weakly sensitive to the form of the function δ (R) and insensitive to its asymptotic value δ∞ .

  10. Dynamic water vapor and temperature calibration system.

    Science.gov (United States)

    Montague, F W; Primiano, F P; Saidel, G M

    1984-06-01

    The objective evaluation of thermal and humidification processes in the pulmonary system requires accurate dynamic measurements of temperature and water vapor concentration of a flowing gas mixture. The adequacy of instruments used for such measurements can only be determined by dynamic calibration techniques. We have developed a method of producing step changes in temperature and water vapor content of a gas mixture undergoing controlled steady flow. The system consists of two reservoirs and a slide valve that switches a test section between them. The inlet (usually a probe or catheter tip) of the device to be calibrated is positioned in the test section. The flow rate through the test section is minimally changed during the transition between gas from one reservoir to that of the other. The system has been used to analyze the response of a thermistor and a respiratory mass spectrometer to changes in gas temperature and water vapor.

  11. A microprocessor-controlled anaesthetic vaporizer.

    Science.gov (United States)

    Hahn, C E; Palayiwa, E; Sugg, B R; Lindsay-Scott, D

    1986-10-01

    A microprocessor-controlled anaesthetic vaporizer is described. Fresh gas is mixed in the correct proportions using two pulsed solenoid valves and a proportion of this passes through a third pulsed solenoid valve and is bubbled through liquid halothane. The temperature of the liquid agent is measured and the pulse frequency is modified to give the correct vapour concentration for the set flow rate and measured temperature. Initially, the vapour was produced by bubbling fresh gas through the agent in a conventional halothane bottle. However, because of the large liquid volume available, nitrous oxide was found to dissolve in large quantities in the halothane. A small volume vaporizer which was continually replenished from a reservoir was designed. Measurements of the vapour concentrations emerging from such a vaporizer were made and were found to agree with the set values +/- 0.1% v/v.

  12. An optical waveguide acid vapor sensor.

    Science.gov (United States)

    Ballantine, D S; Callahan, D; Maclay, G J; Stetter, J R

    1992-12-01

    An optical waveguide sensor for the detection of acid vapors is described. The chemically sensitive reagent coating consists of bromothymol blue indicator suspended in a Nafion polymer film. The sensor uses a 562 nm LED source and a phototransistor detector. Response to hydrochloric acid and hydrogen sulphide vapours is both rapid and reversible, with an estimated detection limit for hydrogen sulphide of less than 15 ppm. The sensors exhibits generalized response to protonic acid vapours, but does not produce an indicator response to carbon dioxide, even at large concentrations (1100 mg/l.) in the presence of water vapor. The sensor exhibits a systematic interference from water vapor which may be corrected by a different approach, either using a reference sensor (Nafion/no indicator) or by monitoring sensor response at two wavelengths.

  13. Refraction of microwave signals by water vapor

    Science.gov (United States)

    Goldfinger, A. D.

    1980-01-01

    Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

  14. Secondhand Exposure to Vapors From Electronic Cigarettes

    Science.gov (United States)

    Czogala, Jan; Fidelus, Bartlomiej; Zielinska-Danch, Wioleta; Travers, Mark J.; Sobczak, Andrzej

    2014-01-01

    Introduction: Electronic cigarettes (e-cigarettes) are designed to generate inhalable nicotine aerosol (vapor). When an e-cigarette user takes a puff, the nicotine solution is heated and the vapor is taken into lungs. Although no sidestream vapor is generated between puffs, some of the mainstream vapor is exhaled by e-cigarette user. The aim of this study was to evaluate the secondhand exposure to nicotine and other tobacco-related toxicants from e-cigarettes. Materials and Methods: We measured selected airborne markers of secondhand exposure: nicotine, aerosol particles (PM2.5), carbon monoxide, and volatile organic compounds (VOCs) in an exposure chamber. We generated e-cigarette vapor from 3 various brands of e-cigarette using a smoking machine and controlled exposure conditions. We also compared secondhand exposure with e-cigarette vapor and tobacco smoke generated by 5 dual users. Results: The study showed that e-cigarettes are a source of secondhand exposure to nicotine but not to combustion toxicants. The air concentrations of nicotine emitted by various brands of e-cigarettes ranged from 0.82 to 6.23 µg/m3. The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes (31.60±6.91 vs. 3.32±2.49 µg/m3, respectively; p = .0081). Conclusions: Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions. PMID:24336346

  15. Secondhand exposure to vapors from electronic cigarettes.

    Science.gov (United States)

    Czogala, Jan; Goniewicz, Maciej L; Fidelus, Bartlomiej; Zielinska-Danch, Wioleta; Travers, Mark J; Sobczak, Andrzej

    2014-06-01

    Electronic cigarettes (e-cigarettes) are designed to generate inhalable nicotine aerosol (vapor). When an e-cigarette user takes a puff, the nicotine solution is heated and the vapor is taken into lungs. Although no sidestream vapor is generated between puffs, some of the mainstream vapor is exhaled by e-cigarette user. The aim of this study was to evaluate the secondhand exposure to nicotine and other tobacco-related toxicants from e-cigarettes. We measured selected airborne markers of secondhand exposure: nicotine, aerosol particles (PM(2.5)), carbon monoxide, and volatile organic compounds (VOCs) in an exposure chamber. We generated e-cigarette vapor from 3 various brands of e-cigarette using a smoking machine and controlled exposure conditions. We also compared secondhand exposure with e-cigarette vapor and tobacco smoke generated by 5 dual users. The study showed that e-cigarettes are a source of secondhand exposure to nicotine but not to combustion toxicants. The air concentrations of nicotine emitted by various brands of e-cigarettes ranged from 0.82 to 6.23 µg/m(3). The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes (31.60±6.91 vs. 3.32±2.49 µg/m(3), respectively; p = .0081). Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions.

  16. Flammability characteristics of combustible gases and vapors

    Energy Technology Data Exchange (ETDEWEB)

    Zabetakis, M. G. [Bureau of Mines, Pittsburgh, PA (United States)

    1964-05-01

    This is a summary of the available limit of flammability, autoignition and burning-rate data for more than 200 combustible gases and vapors in air and other oxidants, as well as of empirical rules and graphs that can be used to predict similar data for thousands of other combustibles under a variety of environmental conditions. Spec$c data are presented on the paraffinic, unsaturated, aromatic, and alicyclic hydrocarbons, alcohols, ethers, aldehydes, ketones, and sulfur compounds, and an assortment of fuels, fuel blends, hydraulic fluids, engine oils, and miscellaneous combustible gases and vapors.

  17. Low temperature vapor phase digestion of graphite

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Robert A.

    2017-04-18

    A method for digestion and gasification of graphite for removal from an underlying surface is described. The method can be utilized to remove graphite remnants of a formation process from the formed metal piece in a cleaning process. The method can be particularly beneficial in cleaning castings formed with graphite molding materials. The method can utilize vaporous nitric acid (HNO.sub.3) or vaporous HNO.sub.3 with air/oxygen to digest the graphite at conditions that can avoid damage to the underlying surface.

  18. Drag Reduction by Leidenfrost Vapor Layers

    KAUST Repository

    Vakarelski, Ivan Uriev

    2011-05-23

    We demonstrate and quantify a highly effective drag reduction technique that exploits the Leidenfrost effect to create a continuous and robust lubricating vapor layer on the surface of a heated solid sphere moving in a liquid. Using high-speed video, we show that such vapor layers can reduce the hydrodynamic drag by over 85%. These results appear to approach the ultimate limit of drag reduction possible by different methods based on gas-layer lubrication and can stimulate the development of related energy saving technologies.

  19. The vertical distribution of Mars water vapor

    Science.gov (United States)

    Davies, D. W.

    1979-01-01

    Analysis of observations made from the Viking 1 Orbiter indicates that the water vapor over the Viking 1 landing site is uniformly mixed with the atmosphere and not concentrated near the surface. The analysis incorporates the effects of atmospheric scattering and explains why previous earth-based observations showed a strong diurnal variation in water content. It also explains the lack of an early morning fog and removes the necessity of daily exchange of large amounts of water between the surface and the atmosphere. A water vapor volume mixing ratio of 1.5 x 10 to the -4th is inferred for the Viking 1 site in late summer.

  20. Catalytic combustion with incompletely vaporized residual fuel

    Science.gov (United States)

    Rosfjord, T. J.

    1981-01-01

    Catalytic combustion of fuel lean mixtures of incompletely vaporized residual fuel and air was investigated. The 7.6 cm diameter, graded cell reactor was constructed from zirconia spinel substrate and catalyzed with a noble metal catalyst. Streams of luminous particles exited the rector as a result of fuel deposition and carbonization on the substrate. Similar results were obtained with blends of No. 6 and No. 2 oil. Blends of shale residual oil and No. 2 oil resulted in stable operation. In shale oil blends the combustor performance degraded with a reduced degree of fuel vaporization. In tests performed with No. 2 oil a similar effect was observed.

  1. Validation of the thermal balance of Laguna Verde turbine under conditions of extended power increase; Validacion del balance termico de turbina de Laguna Verde en condiciones de aumento de potencia extendido

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda G, M. A.; Cruz B, H. J.; Mercado V, J. J.; Cardenas J, J. B.; Garcia de la C, F. M., E-mail: miguel.castaneda01@cfe.gob.mx [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Carretera Cardel-Nautla Km 42.5, Alto Lucero, Veracruz (Mexico)

    2012-10-15

    The present work is a continuation of the task: Modeling of the vapor cycle of Laguna Verde with the PEPSE code to conditions of thermal power licensed at present (2027 MWt) in which the modeling of the vapor cycle of the nuclear power plant of Laguna Verde was realized with PEPSE code (Performance Evaluation of Power System Efficiencies). Once reached the conditions of nominal operation of extended power increase, operating both units to 2371 MWt; after the tests phase of starting-up and operation is necessary to carry out a verification of the proposed design of the vapor cycle for the new operation conditions. All this, having in consideration that the vapor cycle designer only knows the detail of the prospective performance of the main turbine, for all the other components (for example pumps, heat inter changers, valves, reactor, humidity separators and re-heaters, condensers, etc.) makes generic suppositions based on engineering judgment. This way carries out the calculations of thermal balance to determine the guaranteed gross power. The purpose of the present work is to comment the detail of the validation carried out of the specific thermal balance (thermal kit) of the nuclear power plant, making use of the design characteristics of the different components that conform the vapor cycle. (Author)

  2. Comparison of molecular models of carbon monoxide for calculation of vapor-liquid equilibrium

    Directory of Open Access Journals (Sweden)

    Bibian Alonso Hoyos-Madrigal

    2015-01-01

    Full Text Available Existen varios modelos moleculares para el monóxido de carbono desarrollados a partir de diferentes mediciones experimentales. El objetivo de este trabajo es comparar los resultados que varios de estos modelos producen en el cálculo del equilibrio líquido-vapor en busca de recomendar qué modelo debe ser usado de acuerdo la propiedad y la fase que se desea calcular. Los modelos seleccionados corresponden a cuatro modelos no polares, con uno o dos sitios Lennard-Jones, y cuatro modelos polares, con dipolos o cargas parciales para representar la polaridad del monóxido de carbono. Simulaciones Monte Carlo en la versión Gibbs canónica (NVT-GEMC se emplearon para determinar las densidades de las fases en equilibrio, la presión de vapor y la entalpia de vaporización entre 80 y 130 K con cada uno de los modelos seleccionados. Se encontró que los modelos más complejos SVH, ANC y PGB, son los que mejor describen la densidad del líquido saturado (alrededor de 7% de desviación promedio, pero estos modelos generan desviaciones mayores al 40% para las propiedades del vapor y al 20% para la entalpia de vaporización. Por otro lado, el modelo no- polar BLF generó las menores desviaciones para la presión de saturación y la densidad del vapor (6.8 y 21.5%, respectivamente. Este modelo, al igual que el modelo HCB, produce desviaciones aceptables para la densidad del líquido y la entalpia de vaporización (entre 10 y 12%. Los modelos no polares BLF y HCB, que no requieren el cálculo de las interacciones de largo alcance, se pueden considerar como los modelos moleculares que presentan un balance satisfactorio entre desviaciones en los resultados y complejidad de cálculo.

  3. 10 conference and Latin American turbomachinery exhibition; 10 congreso y exposicion latinoamericana de turbomaquinaria

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-15

    This conference was done to promote the exchange of experiences among specialists, users, manufactures and research institutions in the field of the turbomachinery. To spread the last researches and developments focus to the design and maintenance of steam, gas and hydraulic turbines, axial compressors and centrifugal pumps, fans, electric motors, auxiliary equipment and cogeneration. [Spanish] Este congreso se realizo con el fin de promover el intercambio de experiencias entre especialistas, usuarios, fabricantes e institutos de investigacion en el campo de la turbomaquinaria. Divulgar las ultimas investigaciones y desarrollos enfocados al diseno y mantenimiento de turbinas de vapor, de gas e hidraulicas, compresores axiales y centrifugos, bombas, ventiladores, motores electricos, equipos auxiliares y cogeneracion.

  4. Pérdidas de presión en tuberías de vapor

    OpenAIRE

    Luis Enrique Vega Peña; Luis Enrique Rodríguez González

    2007-01-01

    Se presenta una metodología de cálculo para la evaluación del comportamiento de las pérdidas de presión por fricción, caídas de presión en tuberías que transportan vapor como medio de calentamiento o generación de energía eléctrica. El método de cálculo descrito es el resultado de un cuidadoso estudio bibliográfico realizado a literaturas técnicas especializadas en el tema de transporte y utilización del vapor; logrando con esto una herramienta de cálculo ingenieril para especialistas en p...

  5. Carbón activado de semillas de tomate para adsorción de vapores de amoniaco, benceno y gasolina//Activated coal of tomato seeds for adsorption of vapors of ammonia, benzene and gasoline

    Directory of Open Access Journals (Sweden)

    Francisco Márquez-Montesino

    2013-05-01

    Full Text Available El objetivo fue comprobar las posibilidades de adsorción de amoniaco, benceno y gasolina en carbones activados, de semillas de tomate. Se realizó un análisis inmediato a la biomasa. Se concluyó que la adsorción de vapores de amoniaco, está relacionada con la adsorción física y con la presencia de gruposfuncionales de carácter ácido en la superficie activa de los carbones, que forman enlaces débiles con las moléculas de amoniaco. Se realizaron experimentos de adsorción de benceno y gasolina, que no tienen grupos funcionales como el amoniaco, siendo menos adsorbidos, confirmándose una adsorción preferentemente química. La temperatura de activación, la relación de impregnación (RI y laconcentración de la disolución ácida, no tuvieron una influencia significativa en la capacidad de adsorción de benceno, pero sí en la adsorción de amoniaco y vapores de gasolina, de gran aplicación para la eliminación de los vapores de escape en los motores de vehículos.Palabras claves: carbón, activación, adsorción, vapores, amoníaco._______________________________________________________________________________AbstractThe objective was to prove the adsorption possibilities of ammonia, benzene and vapors of gasoline in activated coals with phosphoric acid, of tomato seed. An immediate analysis to the biomass was carried out. It was concluded that the vapors adsorption of ammonia, is related with the physical adsorption andthe presence of functional groups of acid character in the active surface of the coal that form weak connections with the molecules of ammonia. Experiments of adsorption of benzene and gasoline were carried out, these substances haven't functional groups as the ammonia, so they were less adsorbed, and it was confirmed a chemical adsorption preferably. The activation temperature, the relationship of impregnation (RI and the concentration of the acid dissolution haven't a significant influence in the capacity of

  6. Las ondas en las universidades o las universidades en las ondas

    Directory of Open Access Journals (Sweden)

    Verónica Marín Díaz

    2014-01-01

    Full Text Available En las aulas y pasillos de las universidades vuelven a sonar las ondas hercianas que raen una variedad de programas a la anodina vida de la comunidad universitaria, inmersa en la implantación de títulos de Grado, nuevos programas de doctorado, legislación universitaria variable y un largo etcétera que afecta al devenir de la vida en el ámbito de la educación superior.

  7. Las incubadoras de las empresas de Quebec

    Directory of Open Access Journals (Sweden)

    Bernardo Parra Restrepo

    1993-01-01

    Full Text Available Este articulo contiene información de las incubadoras de empresas especialmente aquellas encontradas en Quebec. A través de los 80's, el concepto de incubadoras de empresas fue introducido en América por expertos en el desarrollo económico. Sus metas fueron el estudio de los efectos del desempleo resultante de la quiebra de plantas industriales o del uso del proceso de producción automático por parte de las grandes compañías. Además se esperaba crear empleo para los inmigrantes. El campo más prometedor de estas experiencias se encuentra en el desarrollo de alta tecnología industrial, especialmente en electrónica, microprocesadores y software para sistemas de computación. Esta área también cubre las industrias innovadoras.

  8. Las fronteras del istmo

    OpenAIRE

    Affre, Nathalie; Alvarenga, Patricia; Arriola, Aura Marina; Bastian, Jean-Pierre; Bovin, Philippe; Burne, Stella Maris Arnaiz; Carrillo, Ana Lorena; Casillas R, Rodolfo; Castillo, Manuel Ángel; Córdova, Juan Pohlenz; Cosío, María Eugenia Zavala de; Dachary, Alfredo César; Dauzier, Martine; Demyk, Noelle; Douzant-Rosenfeld, Denise

    2013-01-01

    Obra organizada en torno a seis ejes principales que estudian la importancia de comparar las fronteras y los tipos de gestión desde el punto de vista geopolítico, histórico y antropológico; las tramas de la organización del espacio actual; la influencia en la evolución de las sociedades debido a la violencia política y los conflictos armados; los movimientos migratorios internacionales; la integración política y económica y finalmente los lazos comunitarios y de las identidades relacionados c...

  9. External fuel vaporization study, phase 2

    Science.gov (United States)

    Szetela, E. J.; Chiappetta, L.

    1981-01-01

    An analytical study was conducted to evaluate the effect of variations in fuel properties on the design of an external fuel vaporizaton system. The fuel properties that were considered included thermal stability, critical temperature, enthalpy a critical conditions, volatility, and viscosity. The design parameters that were evaluated included vaporizer weight and the impact on engine requirement such as maintenance, transient response, performance, and altitude relight. The baseline fuel properties were those of Jet A. The variation in thermal stability was taken as the thermal stability variation for Experimental Referee Broad Specification (ERBS) fuel. The results of the analysis indicate that a change in thermal stability equivalent to that of ERBS would increase the vaporization system weight by 20 percent, decrease oprating time between cleaning by 40 percent and make altitude relight more difficult. An increase in fuel critical temperature of 39 K would require a 40 percent increase in vaporization system weight. The assumed increase in enthalpy and volatility would also increase vaporizer weight by 40 percent and make altitude relight extremely difficult. The variation in fuel viscosity would have a negligible effect on the design parameters.

  10. Vapor Bubbles in Flow and Acoustic Fields

    NARCIS (Netherlands)

    Prosperetti, Andrea; Hao, Yue; Sadhal, S.S

    2002-01-01

    A review of several aspects of the interaction of bubbles with acoustic and flow fields is presented. The focus of the paper is on bubbles in hot liquids, in which the bubble contains mostly vapor, with little or no permanent gas. The topics covered include the effect of translation on condensation

  11. Automated semiconductor vacuum chemical vapor deposition facility

    Science.gov (United States)

    1982-01-01

    A semiconductor vacuum chemical vapor deposition facility (totally automatic) was developed. Wafers arrived on an air track, automatically loaded into a furnace tube, processed, returned to the track, and sent on to the next operation. The entire process was controlled by a computer.

  12. Multilead, Vaporization-Cooled Soldering Heat Sink

    Science.gov (United States)

    Rice, John

    1995-01-01

    Vaporization-cooled heat sink proposed for use during soldering of multiple electrical leads of packaged electronic devices to circuit boards. Heat sink includes compliant wicks held in grooves on edges of metal fixture. Wicks saturated with water. Prevents excessive increases in temperature at entrances of leads into package.

  13. Vaporization of atherosclerotic plaques by spark erosion

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); C.E. Essed; J.C.H. Schuurbiers (Johan); N. Bom (Klaas); P.W.J.C. Serruys (Patrick); G.T. Meester (Geert)

    1985-01-01

    textabstractAn alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and

  14. New Medical Applications Of Metal Vapor Lasers

    Science.gov (United States)

    Anderson, Robert S.; McIntosh, Alexander I.

    1989-06-01

    The first medical application for metal vapor lasers has been granted marketing approval by the FDA. This represents a major milestone for this technology. Metalaser Technologies recently received this approval for its Vasculase unit in the treatment of vascular lesions such as port wine stains, facial telangiectasia and strawberry hemangiomas.

  15. Atomic lithium vapor laser isotope separation

    CERN Document Server

    Olivares, I E

    2002-01-01

    An atomic vapor laser isotope separation in lithium was performed using tunable diode lasers. The method permits also the separation of the isotopes between the sup 6 LiD sub 2 and the sup 7 LiD sub 1 lines using a self-made mass separator which includes a magnetic sector and an ion beam designed for lithium. (Author)

  16. Vaporization of synthetic fuels. Final report. [Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Sirignano, W.A.; Yao, S.C.; Tong, A.Y.; Talley, D.

    1983-01-01

    The problem of transient droplet vaporization in a hot convective environment is examined. The main objective of the present study is to develop an algorithm for the droplet vaporization which is simple enough to be feasibly incorporated into a complete spray combustion analysis and yet will also account for the important physics such as liquid-phase internal circulation, unsteady droplet heating and axisymmetric gas-phase convection. A simplified liquid-phase model has been obtained based on the assumption of the existence of a Hill's spherical vortex inside the droplet together with some approximations made in the governing diffusion equation. The use of the simplified model in a spray situation has also been examined. It has been found that droplet heating and vaporization are essentially unsteady and droplet temperature is nonuniform for a significant portion of its lifetime. It has also been found that the droplet vaporization characteristic can be quite sensitive to the particular liquid-phase and gas-phase models. The results of the various models are compared with the existing experimental data. Due to large scattering in the experimental measurements, particularly the droplet diameter, no definite conclusion can be drawn based on the experimental data. Finally, certain research problems which are related to the present study are suggested for future studies.

  17. Vapor Intrusion Characterization Report (Revision 1.0)

    Science.gov (United States)

    Vapor Intrusion Characterization Report (Revision 1) - February 5, 2015: This report, which was approved by the EPA on February 18, 2015, documents the results from implementation of the Final Vapor Intrusion Characterization Work Plan.

  18. Water vapor movement in freezing aggregate base materials.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

  19. Microwave Plasma Enhanced Chemical Vapor Deposition of Diamond in Vapor of Methanol-Based Liquid Solutions

    National Research Council Canada - National Science Library

    Tzeng, Yonhua

    2000-01-01

    .... An electrical discharge is generated by microwave power in a metal cavity in order to dissociate the vapor mixture from one of the liquid solutions, from which radicals such as OH, O, and H that etch...

  20. Vaporization of fault water during seismic slip

    Science.gov (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    2017-06-01

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  1. Vapor condensation behind the shock wave in vapor-liquid two-phase media

    Science.gov (United States)

    Syoji, Chiharu; Oshiro, Naoto

    Laser extinction, schlieren photography, and in situ pressure measurements are used to characterize vapor condensation behind a shock wave in a diaphragm shock tube with a low-pressure chamber filled with ethanol, water, or freon-11 vapor. The experimental setup is briefly described, and the results are presented graphically and discussed in detail. Condensation, lasting a few hundred microsec before reevaporation sets in, is found to decrease the intensity of the shock front and lower the pressure behind it.

  2. The Influence of Chemical Composition on LNG Pool Vaporization

    OpenAIRE

    Yu Zhidong

    2017-01-01

    A model is used to examine the influence of chemical composition on the vaporization rate of LNG during spreading. Calculations have been performed whereby the vaporization rate of the LNG mixtures has been compared to the vaporization of pure methane under the initial conditions. The detailed results indicate that the vaporization rate LNG mixture is different to that of pure methane. LNG as the liquid mixture gets rich in ethane and isobaric latent heat increases rapidly, leading to the rat...

  3. Convective vaporization of particles in an electromagnetic radiation field

    Science.gov (United States)

    Kuznetsov, P. V.; Kurochkin, V. I.

    1987-03-01

    The heating and vaporization of spherical particles in the case of the arbitrary relative concentration of vapor and gas are studied on the basis of the exact equations of multicomponent gas dynamics with allowance for the temperature dependence of the transport coefficients. The proposed method makes possible an easy computation of the vaporization rate and temperature in a wide range of particle sizes and radiation flux densities. The results obtained can be used to calculate laser-induced breakdown in metal vapors.

  4. Las ruinas y las sombras de Manderley

    Directory of Open Access Journals (Sweden)

    Donapetry Camacho, María

    2010-02-01

    Full Text Available The ruins and the shadows of Manderley explores possible reciprocal interpretative relations between Daphne du Maurier’s novel Rebecca and Alfred Hitchcock’s cinematic version. Some of the relevant aspects considered here are: the treatment of the Derridean “ruins of memory” within the novel and within Hitchcock himself, the differentiation and the confrontation of the protagonist as outsider vis á vis the world of Manderley’s insiders, the iconic and symbolic values of the literary text and its filmic visualization, and the ethical positions implied by the choice or rejection of certain narrative devices in both works.

    Las ruinas y las sombras de Manderley aborda posibles relaciones interpretativas recíprocas entre la novela de Daphne du Maurier Rebecca y la película homónima de Alfred Hitchcock. Algunos de los aspectos que se consideran relevantes en este estudio son: el tratamiento de las “ruinas de la memoria” derridianas dentro de la novela y del propio Hitchcock, la diferenciación y el enfrentamiento de la protagonista “externa” con el mundo de los “internos” de Manderley, los valores icónicos y simbólicos del texto literario y de la visualización fílmica, y las posiciones éticas que implican la elección o el rechazo de ciertos recursos narrativos en ambas obras.

  5. Las hierbas marinas.

    OpenAIRE

    Baisre, J. A.

    2007-01-01

    Principales tipos y características distintivas de las hierbas marinas: hierba de tortuga marina Thalassia testudinum, hierba de manatí Syringodium filiforme y la hierba de bajío Halodule wrigti. Las mismas sirven como alimento a muchas especies marinas.

  6. 21 CFR 888.4220 - Cement monomer vapor evacuator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement monomer vapor evacuator. 888.4220 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4220 Cement monomer vapor evacuator. (a) Identification. A cement monomer vapor evacuator is a device intended for use during surgery to contain or remove...

  7. 33 CFR 157.132 - Cargo tanks: Hydrocarbon vapor emissions.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Cargo tanks: Hydrocarbon vapor... § 157.132 Cargo tanks: Hydrocarbon vapor emissions. Each tank vessel having a COW system under § 157.10a... must have— (a) A means to discharge hydrocarbon vapors from each cargo tank that is ballasted to a...

  8. 40 CFR 52.787 - Gasoline transfer vapor control.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer vapor control. (a) Gasoline means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

  9. 40 CFR 52.255 - Gasoline transfer vapor control.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer vapor control. (a) “Gasoline” means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

  10. 33 CFR 154.810 - Vapor line connections.

    Science.gov (United States)

    2010-07-01

    ...) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.810 Vapor... the OCIMF International Safety Guide for Oil Tankers and Terminals (incorporated by reference; see § 154.106). (h) A vapor collection system fitted with an enriching system that operates at a positive...

  11. Packed-bed catalytic cracking of oak derived pyrolytic vapors

    Science.gov (United States)

    Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 deg C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 deg C in a 5 kg/hr bench-scale fast pyrolysis reactor system downstream the cyclone s...

  12. The one year outcome after KTP laser vaporization of the prostate according to the calculated vaporized volume.

    Science.gov (United States)

    Ku, Ja Hyeon; Cho, Jeong Yeon; Cho, Sung Yong; Kim, Soo Woong; Paick, Jae-Seung

    2009-12-01

    The aim of this study was to develop a new simple method for measuring the vaporized volume and to evaluate the outcome of high-power potassium-titanyl-phosphate (KTP) photoselective laser vaporization. A total of 65 patients, with a mean age of 67.7 yr (range 53 to 85), were included in the primary analysis. The vaporized volume was calculated as the pre-operative volume minus the immediate post-operative volume plus the volume of the defect. For all patients, the subjective and objective parameters improved significantly after surgery. Six and 12 months after surgery, the group with a smaller vaporized volume (vaporized volume (>or=15 g). There were no differences in the change of the maximum flow rate and post-void residual based on the vaporized volume. Our findings suggest that the subjective improvement, after a high-power KTP laser vaporization, may be dependent on the vaporized volume obtained after the procedure.

  13. Membrane-assisted vapor stripping: energy efficient hybrid distillation-vapor permeation process for alcohol-water separation

    Science.gov (United States)

    BACKGROUND: Energy efficient alternatives to distillation for alcohol recovery from dilute solution are needed to improve biofuel sustainability. A process integrating steam stripping with a vapor compression step and a vapor permeation membrane separation step is proposed. The...

  14. Chemical agent simulant release from clothing following vapor exposure.

    Science.gov (United States)

    Feldman, Robert J

    2010-02-01

    Most ambulatory victims of a terrorist chemical attack will have exposure to vapor only. The study objective was to measure the duration of chemical vapor release from various types of clothing. A chemical agent was simulated using methyl salicylate (MeS), which has similar physical properties to sulfur mustard and was the agent used in the U.S. Army's Man-In-Simulant Test (MIST). Vapor concentration was measured with a Smiths Detection Advanced Portable Detector (APD)-2000 unit. The clothing items were exposed to vapor for 1 hour in a sealed cabinet; vapor concentration was measured at the start and end of each exposure. Clothing was then removed and assessed every 5 minutes with the APD-2000, using a uniform sweep pattern, until readings remained 0. Concentration and duration of vapor release from clothing varied with clothing composition and construction. Lightweight cotton shirts and jeans had the least trapped vapor; down outerwear, the most. Vapor concentration near the clothing often increased for several minutes after the clothing was removed from the contaminated environment. Compression of thick outerwear released additional vapor. Mean times to reach 0 ranged from 7 minutes for jeans to 42 minutes for down jackets. This simulation model of chemical vapor release demonstrates persistent presence of simulant vapor over time. This implies that chemical vapor may be released from the victims' clothing after they are evacuated from the site of exposure, resulting in additional exposure of victims and emergency responders. Insulated outerwear can release additional vapor when handled. If a patient has just moved to a vapor screening point, immediate assessment before additional vapor can be released from the clothing can lead to a false-negative assessment of contamination.

  15. en las relaciones entrenadas

    Directory of Open Access Journals (Sweden)

    Camilo Hurtado P.

    2005-01-01

    Full Text Available El presente estudio exploró los efectos en la adquisición y transferencia de discriminaciones condicionales debidos a las diferentes combinaciones de relaciones entrenadas (identidad-diferencia-semejanza en una tarea de igualación a la muestra de segundo orden. De manera complementaria, fueron además dispuestas en la tarea las características que en estudios relacionados habían sido reportadas como facilitadoras de ejecuciones efectivas, a saber: el uso de instrucciones inespecíficas, arreglos de estímulo de tres formas y dos colores y el entrenamiento concurrente de las relaciones. Ocho sujetos fueron distribuidos en cuatro grupos que variaron en la combinación de relaciones a entrenar. Los resultados mostraron que gran parte de los sujetos cumplieron con el criterio de efectividad en entrenamiento y en transferencia extramodal y extrarrelacional, siendo la relación de identidad la relación en la cual se presentaron ejecuciones perfectas, al margen de si ésta había sido entrenada o no. Se discuten los resultados en términos de velocidad de ajuste a las relaciones y de las configuraciones de la tarea que facilitaron mejores desempeños. Se proponen, además, posibles investigaciones que superen las limitaciones metodológicas encontradas en este estudio y que exploren posibles interacciones de las variables manipuladas con otras variables de interés.

  16. Experimental study of external fuel vaporization

    Science.gov (United States)

    Szetela, E. J.; Tevelde, J. A.

    1982-01-01

    The fuel properties used in the design of a flash vaporization system for aircraft gas turbine engines were evaluated in experiments using a flowing system to determine critical temperature and pressure, boiling points, dew points, heat transfer coefficients, deposit formation rates, and deposit removal. Three fuels were included in the experiments: Jet-A, an experimental referree broad specification fuel, and a premium No. 2 diesel fuel. Engine conditions representing a NASA Energy Efficient Engine at sea-level take-off, cruise, and idle were simulated in the vaporization system and it was found that single phase flow was maintained in the heat exchanger and downstream of the throttle. Deposits encountered in the heat exchanger represented a thermal resistance as high as 1300 sq M K/watt and a deposit formation rate over 1000 gC/sq cm hr.

  17. Experimental vaporization of the Holbrook chondrite

    Science.gov (United States)

    Gooding, J. L.; Muenow, D. W.

    1977-01-01

    The vapor phase composition obtained by heating samples of the Holbrook L6 chondrite to 1300 C was determined quantitatively by Knudsen cell-quadrupole mass spectrometry. Maximum observed vapor pressures, produced at 1200 C, are reported for Na, K, Fe, and Ni, and the implications of the Na/K ratio are considered. The Fe and Ni data are discussed with attention to their migration in individual equilibrated chondrites. S2 (with minor SO2), H2O, and CO2 were also present in the high-temperature gas phase. Vesicles formed by the release of intrinsically derived volatiles are compared with vesicles in the Ibitira eucrite. Chondrite evolution is briefly discussed.

  18. Quenching Phase Separation by Vapor Deposition Polymerization

    Science.gov (United States)

    Tao, Ran; Anthamatten, Mitchell

    2015-03-01

    Initiated chemical vapor deposition (iCVD) is a solventless, free radical technique predominately used to deposit homogeneous films of linear and crosslinked polymers directly from gas phase feeds. We report a template-free method to fabricate continuous-phase porous polymer films by simultaneous phase separation during iCVD. Phase separation during film growth is achieved by condensing an inert porogen, along with initiator, monomer, and crosslinker. When the vapor mixture transports to the cooled substrate, phase separation occurs along with polymerization and crosslinking, which quench the state of phase separation. The kinetics of spontaneously phase separation can be qualitatively understood on the basis of Cahn-Hilliard theory. A series of films were grown by varying monomer and porogen's degree of saturation. Deposited films were studied by electron microscopy and spectroscopic techniques.

  19. The toxicity of inhaled methanol vapors.

    Science.gov (United States)

    Kavet, R; Nauss, K M

    1990-01-01

    Methanol could become a major automotive fuel in the U.S., and its use may result in increased exposure of the public to methanol vapor. Nearly all of the available information on methanol toxicity in humans relates to the consequences of acute, rather than chronic, exposures. Acute methanol toxicity evolves in a well-understood pattern and consists of an uncompensated metabolic acidosis with superimposed toxicity to the visual system. The toxic properties of methanol are rooted in the factors that govern both the conversion of methanol to formic acid and the subsequent metabolism of formate to carbon dioxide in the folate pathway. In short, the toxic syndrome sets in if formate generation continues at a rate that exceeds its rate of metabolism. Current evidence indicates that formate accumulation will not challenge the metabolic capacity of the folate pathway at the anticipated levels of exposure to automotive methanol vapor.

  20. Gradient Solvent Vapor Annealing of Thin Films

    Science.gov (United States)

    Albert, Julie; Bogart, Timothy; Lewis, Ronald; Epps, Thomas

    2011-03-01

    The development of block copolymer materials for emerging nanotechnologies requires an understanding of how surface energy/chemistry and annealing conditions affect thin film self-assembly. Specifically, in solvent vapor annealing (SVA), the use of solvent mixtures and the manipulation of solvent vapor concentration are promising approaches for obtaining a desired morphology or nanostructure orientation. We designed and fabricated solvent-resistant devices to produce discrete SVA gradients in composition and/or concentration to efficiently explore SVA parameter space. We annealed copolymer films containing poly(styrene), poly(isoprene), and/or poly(methyl methacrylate) blocks, monitored film thicknesses during annealing, and characterized film morphologies with atomic force microscopy. Morphological changes across the gradients such as the transformation from parallel cylinders to spheres with increasing solvent selectivity provided insight into thin film self-assembly, and the gradient device has enabled us to determine transition compositions and/or concentrations.

  1. Vapor-induced phase transformations in docetaxel.

    Science.gov (United States)

    Tatini, Lakshmi Kumar; Krishna Reddy, K V S R; Someswara Rao, N

    2012-06-01

    Vapor-induced transformations of docetaxel anhydrous (form D(A)) under ambient conditions have been studied using methanol, ethanol, and water as the solvent media. The online vapor-induced transformations were monitored by powder X-ray diffractometry. New solid forms (solvates/hydrates/anhydrous) of docetaxel anhydrous were obtained in stoichiometric ratios which were characterized completely using powder X-ray diffraction, differential scanning calorimeter, thermogravimetric analysis, and spectroscopic ((13)C solid-state nuclear magnetic spectroscopy, solution (1)H NMR, and Fourier transform infrared) techniques. The new forms namely methanol solvate (D(M)), ethanol solvate (D(E)), monohydrate (D(MH)), trihydrate (D(TH)), and anhydrous (D(AN-I) and D(AN-II)) were identified through structural analysis.

  2. Detailed Field Investigation of Vapor Intrusion Processes

    Science.gov (United States)

    2008-09-01

    will be conducted and respiratory protective equipment used as needed, as described below. • Eating, drinking, smoking, gum chewing and oral tobacco use...FINAL REPORT Detailed Field Investigation of Vapor Intrusion Processes ESTCP Project ER-0423 September 2008 Thomas E. McHugh, Ph ...Thomas E. McHugh, Ph D. Tim N. Nickels 5d. PROJECT NUMBER ER-0423 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND

  3. Making Ceramic Fibers By Chemical Vapor

    Science.gov (United States)

    Revankar, Vithal V. S.; Hlavacek, Vladimir

    1994-01-01

    Research and development of fabrication techniques for chemical vapor deposition (CVD) of ceramic fibers presented in two reports. Fibers of SiC, TiB2, TiC, B4C, and CrB2 intended for use as reinforcements in metal-matrix composite materials. CVD offers important advantages over other processes: fibers purer and stronger and processed at temperatures below melting points of constituent materials.

  4. Chemical vapor infiltration in single fiber bundles

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Barbero, R.S.; Currier, R.P.

    1990-01-01

    Chemical vapor infiltration (CVI) in single fiber bundles is studied under isothermal conditions. Understanding infiltration dynamics in single bundles is essential to process design and modeling efforts. Deposition of pyrolytic carbon in carbon-fiber bundles is chosen as the experimental system, with densification data obtained from thermogravimetric analysis. Data are then compared to predictions from a recently proposed CVI model for fiber bundle densification. 10 refs., 5 figs., 1 tab.

  5. Quality and Control of Water Vapor Winds

    Science.gov (United States)

    Jedlovec, Gary J.; Atkinson, Robert J.

    1996-01-01

    Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor

  6. Inhalation of Alcohol Vapor: Measurement and Implications.

    Science.gov (United States)

    MacLean, Robert Ross; Valentine, Gerald W; Jatlow, Peter I; Sofuoglu, Mehmet

    2017-02-01

    Decades of alcohol research have established the health risks and pharmacodynamic profile of oral alcohol consumption. Despite isolated periods of public health concern, comparatively less research has evaluated exposure to alcohol vapor. Inhaled alcohol initially bypasses first-pass metabolism and rapidly reaches the arterial circulation and the brain, suggesting that this route of administration may be associated with pharmacological effects that increase the risk of addiction. However, detailed reviews assessing the possible effects of inhaled alcohol in humans are lacking. A comprehensive, systematic literature review was conducted using Google Scholar and PubMed to examine manuscripts studying exposure to inhaled alcohol and measurement of biomarkers (biochemical or functional) associated with alcohol consumption in human participants. Twenty-one publications reported on alcohol inhalation. Fourteen studies examined inhalation of alcohol vapor associated with occupational exposure (e.g., hand sanitizer) in a variety of settings (e.g., naturalistic, laboratory). Six publications measured inhalation of alcohol in a controlled laboratory chamber, and 1 evaluated direct inhalation of an e-cigarette with ethanol-containing "e-liquid." Some studies have reported that inhalation of alcohol vapor results in measurable biomarkers of acute alcohol exposure, most notably ethyl glucuronide. Despite the lack of significantly elevated blood alcohol concentrations, the behavioral consequences and subjective effects associated with repeated use of devices capable of delivering alcohol vapor are yet to be determined. No studies have focused on vulnerable populations, such as adolescents or individuals with alcohol use disorder, who may be most at risk of problems associated with alcohol inhalation. Copyright © 2017 by the Research Society on Alcoholism.

  7. Vaporization of atherosclerotic plaques by spark erosion

    OpenAIRE

    Slager, Cornelis J.; Essed, Catharina E.; Schuurbiers, Johan C.H.; Bom, Nicolaas; Serruys, Patrick W.; Meester, Geert T.

    1985-01-01

    textabstractAn alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and documented histologically in vitro from 30 atherosclerotic segments of six human aortic autopsy specimens. Craters with a constant area and a depth that varied according to the duration of application ...

  8. Historia de las series

    OpenAIRE

    Cascajosa Virino, Concepción

    2017-01-01

    Reseña: Historia de las series de Toni de la Torre: la gran impostura Durante mucho tiempo los profesores de cine en España se han quejado (amargamente y en privado) de la recurrencia en la bibliografía de los trabajos de sus estudiantes de los libros de un autor conocido por la escasa calidad de sus textos, cuyos vistosos títulos garantizan que acaben en las estanterías de las bibliotecas universitarias. Es muy propio de la cultura española hacer duras aseveraciones en foros irrelevantes y, ...

  9. Las Leyes de Newton

    OpenAIRE

    González S., Fabio

    2015-01-01

    La labor de Newton en el campo de la física, una de las piedras angulares en que se fundamenta esta ciencia, se caracteriza por el hecho de que a partir de unos enunciados básicos explica los diversos fenómenos que estudia la mecánica. Entre las grandes contribuciones de Newton se pueden citar: el descubrimiento de la ley de la gravitación universal, el enunciado de las leyes del movimiento, el teorema del binomio, la formulación básica del cálculo diferencial e integral, así-como algunos tra...

  10. Las innovaciones en las telecomunicaciones y las nuevas identidades laborales

    Directory of Open Access Journals (Sweden)

    Natalia Aruguete

    2006-12-01

    Full Text Available Este trabajo se propone analizar las modificaciones en la política laboral en el sector de telecomunicaciones haciendo eje en la visión que los trabajadores tienen de ella. De esta manera se intenta contestar a la casi nula o distorsionada cobertura mediática que mereció la problemática de la gestión de la fuerza de trabajo durante el proceso de reestructuración que atravesó el sector. El estudio se basa en la información estadística y en entrevistas en profundidad realizadas a los trabajadores de las empresas de telefonía fija que operan en la Argentina. La vivencia que perdura en los trabajadores – despedidos o no – es que la privatización implicó desestabilizar y fragmentar un modo de vida estructurado a partir de la identidad y cultura laborales. Esa pérdida de sentido de una ética en la que el trabajo es sinónimo de realización personal fue vivida por los trabajadores como humillación y falta de respeto a sus trayectorias laborales y profesionales, una desvalorización de su saber, una falta de reconocimiento personal y social a su trabajo y una persistencia en la incertidumbre acerca del futuro.

  11. Water Vapor Effects on Silica-Forming Ceramics

    Science.gov (United States)

    Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)

    2000-01-01

    Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

  12. Nuclear vapor thermal reactor propulsion technology

    Energy Technology Data Exchange (ETDEWEB)

    Maya, I.; Diaz, N.J.; Dugan, E.T.; Watanabe, Y. (Innovative Nuclear Space Power and Propulsion Institute, University of Florida, Gainesville, Florida 32611 (United States)); McClanahan, J.A.; Wen-Hsiung Tu; Carman, R.L. (Rocketdyne Division/Rockwell International Corporation, P.O. Box 7922, Canoga Park, California 91309-7922 (United States))

    1993-01-20

    The conceptual design of a nuclear rocket based on the vapor core reactor is presented. The Nuclear Vapor Thermal Rocket (NVTR) offers the potential for a specific impulse of 1000 to 1200 s at thrust-to-weight ratios of 1 to 2. The design is based on NERVA geometry and systems with the solid fuel replaced by uranium tetrafluoride (UF[sub 4]) vapor. The closed-loop core does not rely on hydrodynamic confinement of the fuel. The hydrogen propellant is separated from the UF[sub 4] fuel gas by graphite structure. The hydrogen is maintained at high pressure ([similar to]100 atm), and exits the core at 3,100 K to 3,500 K. Zirconium carbide and hafnium carbide coatings are used to protect the hot graphite from the hydrogen. The core is surrounded by beryllium oxide reflector. The nuclear reactor core has been integrated into a 75 klb engine design using an expander cycle and dual turbopumps. The NVTR offers the potential for an incremental technology development pathway to high performance gas core reactors. Since the fuel is readily available, it also offers advantages in the initial cost of development, as it will not require major expenditures for fuel development.

  13. Steady State Vapor Bubble in Pool Boiling.

    Science.gov (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C

    2016-02-03

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  14. Released air during vapor and air cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Jablonská, Jana, E-mail: jana.jablonska@vsb.cz; Kozubková, Milada, E-mail: milada.kozubkova@vsb.cz [VŠB-Technical University of Ostrava, Faculty of Mechanical Engineering, Department of Hydromechanics and Hydraulic Equipment, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)

    2016-06-30

    Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ε model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

  15. Droplet vaporization in a supercritical microgravity environment

    Science.gov (United States)

    Curtis, E. W.; Farrell, P. V.

    A model has been developed for non-convective vaporization of liquid fuel droplets in an environment above the liquid critical pressure and near or above the liquid critical temperature. The model employs conservation of mass, energy and chemical species, along with transport properties which vary with temperature and species concentration. The liquid interface is assumed to be in thermodynamic equilibrium. The interface problem is solved using the Gibbs-Duhem relationship, and evaluating mixture fugacities using a modified Redlich-Kwong equation of state for the mixture. Due to the limited range of this equation, a curve-fit equation of state suitable for conditions far from the liquid critical point was applied. Results are presented for an n-octane liquid drop in nitrogen gas. For two gas conditions, several droplet sizes are modeled. Results include droplet size histories, surface temperature histories, and liquid and gas phase temperature profiles. The liquid vaporization rate is increased significantly for supercritical conditions compared to subcritical conditions. Using the specified equation of state for the ambient conditions tested, the droplet is completely vaporized before the liquid surface is heated to the liquid critical temperature.

  16. Marketing practices of vapor store owners.

    Science.gov (United States)

    Cheney, Marshall; Gowin, Mary; Wann, Taylor Franklin

    2015-06-01

    We examined the marketing strategies for local vapor stores in a large metropolitan area in Oklahoma. Vapor store owners or managers (n = 33) participated in individual interviews regarding marketing practices in 2014. We asked owners about their marketing strategies and the groups they targeted. We transcribed the interviews and analyzed them for themes. Store owners used a variety of marketing strategies to bring new customers to their stores and keep current customers coming back. These marketing strategies showed many parallels to tobacco industry strategies. Most owners engaged in some form of traditional marketing practices (e.g., print media), but only a few used radio or television advertising because of budget constraints. Owners used social media and other forms of electronic communication, pricing discounts and specials, and loyalty programs. Owners also had booths at local events, sponsored community events, and hosted them in their stores. Owners attempted to target different groups of users, such as college students and long-term smokers. Local vapor store marketing practices closely resemble current and former tobacco industry marketing strategies. Surveillance of marketing practices should include local and Web-based strategies.

  17. Marketing Practices of Vapor Store Owners

    Science.gov (United States)

    Gowin, Mary; Wann, Taylor Franklin

    2015-01-01

    Objectives. We examined the marketing strategies for local vapor stores in a large metropolitan area in Oklahoma. Methods. Vapor store owners or managers (n = 33) participated in individual interviews regarding marketing practices in 2014. We asked owners about their marketing strategies and the groups they targeted. We transcribed the interviews and analyzed them for themes. Results. Store owners used a variety of marketing strategies to bring new customers to their stores and keep current customers coming back. These marketing strategies showed many parallels to tobacco industry strategies. Most owners engaged in some form of traditional marketing practices (e.g., print media), but only a few used radio or television advertising because of budget constraints. Owners used social media and other forms of electronic communication, pricing discounts and specials, and loyalty programs. Owners also had booths at local events, sponsored community events, and hosted them in their stores. Owners attempted to target different groups of users, such as college students and long-term smokers. Conclusions. Local vapor store marketing practices closely resemble current and former tobacco industry marketing strategies. Surveillance of marketing practices should include local and Web-based strategies. PMID:25880960

  18. Characterization of a Compact Water Vapor Radiometer

    Science.gov (United States)

    Gill, Ajay; Selina, Rob

    2018-01-01

    We report on laboratory test results of the Compact Water Vapor Radiometer (CWVR) prototype for the Karl G. Jansky Very Large Array (VLA), a five-channel design centered around the 22 GHz water vapor line. Fluctuations in perceptible water vapor cause fluctuations in atmospheric brightness emission, which are assumed to be proportional to phase fluctuations of the astronomical signal seen by an antenna. The design is intended to support empirical radiometric phase corrections for each baseline in the array.The dynamic range, channel isolation, and gain stability of the device were characterized. The device has a useful dynamic range of order 18 dB after calibration, and the CWVR channel isolation requirement of 102.6 sec. With temperature corrections, the single channel and channel difference gain stability per channel is < 2 x 10-4 over τ = 2.5 - 103 sec, which meets the < 2 x 10-4 requirement. The observable gain stability is < 2.5 x 10-4 over τ = 2.5 - 103 sec, which meets the < 2.5 x 10-4 requirement.Overall, the test results indicate that the CWVR meets required specifications for dynamic range, channel isolation, and gain stability in order to proceed with testing on a pair of VLA antennas.

  19. Las fronteras de Israel

    Directory of Open Access Journals (Sweden)

    Arie M. Kacowicz

    2008-01-01

    Full Text Available En el presente artículo haré una breve reseña histórica de la evolución de las fronteras (inconclusas del Estado de Israel entre 1948 y 2007. En primer lugar, presento un modelo teórico sobre el desarrollo y la evolución de las fronteras, tanto por la vía pacífi ca como por la bélica. En segundo lugar, hago una reseña histórica de la evolución de las fronteras de Israel desde su independencia hasta el presente. El artículo también hace referencia detallada a los problemas pendientes con respecto a las negociaciones entre Israel y los palestinos.

  20. Las Serpientes en Colombia

    Directory of Open Access Journals (Sweden)

    Daniel H.

    1949-12-01

    Full Text Available El estudio de las serpientes en Colombia no deja de tener su particular interés; existe una inmensa variedad de especies que se escalonan desde los valles ardientes hasta alturas relativamente considerables; en estos últimos puntos disminuye notablemente la variedad de formas y de modo especial las especies provistas de veneno. Hacer una distinción entre las especies venenosas y las inofensivas, resulta un tanto difícil; en algunos textos se dan unas cuántas reglas, pero la mayor parte de ellas sólo tienen aplicación con especies exóticas ya que la mayor parte de esas distinciones se han tomado de obras que hacen referencia a la fauna europea.

  1. Las protociudades de Mesenia

    Directory of Open Access Journals (Sweden)

    Domingo PLÁCIDO SUÁREZ

    2010-02-01

    Full Text Available RESUMEN: En este artículo se estudian la formación inicial de las ciudades mesenias, las entidades sociales desarrolladas y el incipiente sinecismo, frustrado por la violenta invasión lacedemonia. Palabras clave: Protociudades, Mesenia, invasión espartana.ABSTRACT: A study is made of the initial formation of Messenian cities, the social entities developed and the incipient synechism, frustrated by the violent lacedaemonian invasion.

  2. Las vacas imitadores expertos

    OpenAIRE

    Chevalier, Pedro

    2009-01-01

    La mayoría de las especies del género Hypoplectrus presentan un comportamiento conocido como mimetismo agresivo. Este fenómeno consiste en la imitación de los patrones de coloración, por parte de las vacas, de peces que no son depredadores de crustáceos y pequeños peces. Al imitar el color de peces inofensivos pueden acercarse a sus presas sin que estas huyan.

  3. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

    2009-04-15

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  4. Analysis of the force exercised in pipes by accumulation of water in the head stock of turbine bypass; Analisis de la fuerza ejercida en tuberias por acumulamiento de agua en el cabezal de baipas de turbina

    Energy Technology Data Exchange (ETDEWEB)

    Cecenas F, M.; Ovando C, R.; Campos G, R. M., E-mail: mcf@iie.org.mx [Instituto de Investigaciones Electricas, Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico)

    2011-11-15

    The head stock and valves of turbine bypass allow canalize the main vapor coming from the reactor toward the condenser, without carrying out work in the turbo-generator. In this work is assumed that is accumulates condensed in the head stock during a time period in which the bypass system does not operate. For operation maneuvers, the opening of the bypass is demanded, for what the accumulated water is suddenly dragged by the vapor to high pressure coming from the reactor toward the condenser, which operates to inferior pressures to the atmospheric. The generated flow produces a mechanical effort in the lines and its supports. By means of the RELAP5 code the bypass system is modeled, the discharge transitory to the condenser is simulated and the speeds of the mixture water/vapor are calculated. Processing the exit of RELAP5 the mechanical effort that is subjected the pipe is calculated, and the study is complemented with a sensibility analysis to the quantity of stored water in the volume of the bypass head stock. (Author)

  5. Dynamic headspace generation and quantitation of triacetone triperoxide vapor.

    Science.gov (United States)

    Giordano, Braden C; Lubrano, Adam L; Field, Christopher R; Collins, Greg E

    2014-02-28

    Two methods for quantitation of triacetone triperoxide (TATP) vapor using a programmable temperature vaporization (PTV) inlet coupled to a gas chromatography/mass spectrometer (GC/MS) have been demonstrated. The dynamic headspace of bulk TATP was mixed with clean humid air to produce a TATP vapor stream. Sampling via a heated transfer line to a PTV inlet with a Tenax-TA™ filled liner allowed for direct injection of the vapor stream to a GC/MS for vapor quantitation. TATP was extracted from the vapor stream and subsequently desorbed from the PTV liner for splitless injection on the GC column. Calibration curves were prepared using solution standards with a standard split/splitless GC inlet for quantitation of the TATP vapor. Alternatively, vapor was sampled onto a Tenax-TA™ sample tube and placed into a thermal desorption system. In this instance, vapor was desorbed from the tube and subsequently trapped on a liquid nitrogen cooled PTV inlet. Calibration curves for this method were prepared from direct liquid injection of standards onto samples tube with the caveat that a vacuum is applied to the tube during deposition to ensure that the volatile TATP penetrates into the tube. Vapor concentration measurements, as determined by either GC/MS analysis or mass gravimetry of the bulk TATP, were statistically indistinguishable. Different approaches to broaden the TATP vapor dynamic range, including diluent air flow, sample chamber temperature, sample vial orifice size, and sample size are discussed. Vapor concentrations between 50 and 5400ngL(-1) are reported, with stable vapor generation observed for as long as 60 consecutive hours. Published by Elsevier B.V.

  6. Parmentier, las patatas y las ollas americanas

    Directory of Open Access Journals (Sweden)

    Clément, Jean-Pierre

    1995-12-01

    Full Text Available The discovery of new agricultural and alimentary possibilities was one of the most important motives of the numerous scientific expeditions sent to America during the XVIIIth Century. Some French scientists (naturalists, medical, botanical, etc., undertook, during the second half of the Enlightment Century, an active campaign in favor of the potato consumption. The most well-known was the pharmacist Parmentier that settled his propaganda upon political arguments (the potato gives of eating all the population, economical (it is an easy plant of cultivating and of good efficiency, and scientific (excellent nutritious qualities.

    El descubrimiento de nuevas posibilidades agroalimentarias fue uno de los más importantes motivos de las numerosas expediciones científicas enviadas a América durante el siglo XVIII. Algunos científicos galos (naturalistas, médicos, botánicos, etc., emprendieron, en la segunda mitad del siglo de las Luces, una activa campaña en favor del consumo de la patata por los hombres. El más conocido fue el farmacéutico Parmentier, que asentó su propaganda sobre argumentos políticos (la patata da de comer a toda la población, económicos (es una planta fácil de cultivar y de buen rendimiento, y científicos (excelentes cualidades nutritivas.

  7. Chemical vapor infiltration process modeling and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Matlin, W.M. [Tennessee Univ., Knoxville, TN (United States). Dept. of Materials Science and Engineering

    1995-12-31

    Chemical vapor infiltration is a unique method for preparing continuous fiber ceramic composites that spares the strong but relatively fragile fibers from damaging thermal, mechanical, and chemical degradation. The process is relatively complex and modeling requires detailed phenomenological knowledge of the chemical kinetics and mass and heat transport. An overview of some of the current understanding and modeling of CVI and examples of efforts to optimize the processes is given. Finally, recent efforts to scale-up the process to produce tubular forms are described.

  8. Permeability of MDT chambers to water vapor

    CERN Document Server

    Palestini, S

    2003-01-01

    Tests of MDT chambers performed at the GIF facility and in the H8 test-beam area have shown relative high levels of water vapor contamination in the gas-mixture at the detector output. This effects significantly the drift properties of the MDTs. This note shows that amount of water observed is compatible with approximate estimates based on the permeability of Noryl, used in the tube end-plugs, and of EPDM, used in the O-rings of the on-chamber gas distribution.

  9. Las colonias fronterizas

    Directory of Open Access Journals (Sweden)

    Jeffery Brannon

    1989-09-01

    Full Text Available Este artículo examina el rápido crecimiento de las comunidades irregulares que son habitadas por población de escasos recursos, predominantemente hispana, localizadas en áreas desincorporadas de lado norteamericano de la frontera México-Estados Unidos durante la década de los ochenta. Alrededor de 175 o 200 mil personas actualmente viven en estas llamadas "colonias", mismas que frecuentemente están aisladas de las áreas urbanas cercanas y sin disponer de acceso adecuado a los servicios públicos básicos tales como agua, drenaje y transporte público. La inmigración de mexicanos a los Estados Unidos y la escasez de viviendas a precios módicos están identificados como los factores principales en la creación de estas comunidades. El Paso, Texas es utilizado como caso para el estudio de la dinámica social, política y económica del crecimiento de las "colonias". En este artículo se llega a la conclusión de que serán necesarias inciativas innovadoras, principalmente locales, para minimizar las consecuencias potenciales negativas del desarrollo irregular de anillos de pobreza alrededor de las áreas urbanas ubicadas en el lado norteamericano de la frontera.

  10. Haciendo resonar las voces

    DEFF Research Database (Denmark)

    Tufte, Thomas; Corrigan, Arran; Ekstrøm, Ylva

    2011-01-01

    En su plan estratégico para 2007-2010, el Proyecto de Información para la Salud FEMINA (Tanzania) manifiesta su visión de “una sociedad empoderada que promueve valores democráticos, el pensamiento crítico y actitudes positivas en pos de estilos de vida saludables, la igualdad de género, una...... son vehículos clave de una más amplia estrategia de edu-entretenimiento. La pregunta que se aborda en este artículo es: ¿qué rol pueden jugar las cartas escritas por los y las jóvenes a los que apuntan las intervenciones del proyecto FEMINA en la evaluación y la documentación de los resultados de su...... trabajo? ¿En qué medida las cartas reflejan procesos de empoderamiento, voz y participación? O mejor dicho, ¿qué reflejan las cartas en términos del interés de la audiencia en el proyecto FEMINA, sus propósitos, objetivos y visión? El artículo se centra en los desafíos teórico-metodológicos planteados...

  11. Vaporization of a mixed precursors in chemical vapor deposition for YBCO films

    Science.gov (United States)

    Zhou, Gang; Meng, Guangyao; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1995-01-01

    Single phase YBa2Cu3O7-delta thin films with T(c) values around 90 K are readily obtained by using a single source chemical vapor deposition technique with a normal precursor mass transport. The quality of the films is controlled by adjusting the carrier gas flow rate and the precursor feed rate.

  12. Water recovery by catalytic treatment of urine vapor

    Science.gov (United States)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  13. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    OpenAIRE

    Jeong, Jae; Lee, Sung; Jeon, Je-Beom; Kim, Suk

    2015-01-01

    Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the va...

  14. Lunar absorption spectrophotometer for measuring atmospheric water vapor.

    Science.gov (United States)

    Querel, Richard R; Naylor, David A

    2011-02-01

    A novel instrument has been designed to measure the nighttime atmospheric water vapor column abundance by near-infrared absorption spectrophotometry of the Moon. The instrument provides a simple, effective, portable, and inexpensive means of rapidly measuring the water vapor content along the lunar line of sight. Moreover, the instrument is relatively insensitive to the atmospheric model used and, thus, serves to provide an independent calibration for other measures of precipitable water vapor from both ground- and space-based platforms.

  15. Las finanzas personales

    Directory of Open Access Journals (Sweden)

    Luis Olmedo Figueroa Delgado

    2013-08-01

    Full Text Available El éxito en la administración de las finanzas personales puede provenir de diversos estamentos, sin embargo, se estructura un elemento esencial que permite tomar decisiones consientes y más coherentes en el quehacer diario, el cual es el “presupuesto”, es por ello que en este articulo artículo se tomara esta herramienta financiera como elemento pivote que cumplirá dos fines principales: El resultado lógico y eficiente de una serie de actividades cotidianas que permite tomar decisiones en beneficio personal, en donde podremos entender el vocablo personal si se quiere familiar y el punto de partida para elaborar alguna estrategia que genere un rediseño los gastos o las inversiones actualmente realizadas y de esta manera encontrar un bienestar adicional en la administración de las finanzas personales.

  16. Internet de las cosas

    OpenAIRE

    Salazar Soler, Jorge; Silvestre Bergés, Santiago

    2016-01-01

    Este es un curso de introducción a la IoT (Internet de las cosas). En los capítulos primeros capítulos se introducen los conceptos básicos sobre la IoT. Seguidamente se presentan nociones básicas sobre el protocolo de internet IPv6 que es el más utilizado en el entorno de la IoT y se describen las principales aplicaciones, el estado actual del mercado y las tecnologías que permiten la existencia de la IoT. Finalmente se analizan los retos de futuro que se consideran más importa...

  17. The liquid to vapor phase transition in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

    2001-05-08

    For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

  18. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  19. [Laser vaporization of the prostate: all as it should be?].

    Science.gov (United States)

    Reich, O; Seitz, M

    2008-04-01

    Laser vaporization of the prostate currently occupies a prominent place among the surgical options for treatment of benign prostatic syndrome. Particularly the so-called GreenLight laser vaporization with the KTP (80 W) or LBO (120 W) laser has become remarkably widespread throughout the world. There are already 100 of these GreenLight laser systems in use in Germany alone. The introduction of a separate DRG for "laser vaporization" is expected to further increase the significance of this surgical technique. The aim of this study is to evaluate laser vaporization as a whole and to identify possible differences between the different lasers.

  20. Brujas: las mujeres escriben

    OpenAIRE

    1982-01-01

    Esta publicación es un espacio para darle voz a la mujer: una voz desde la narrativa en femenino a través de la literatura, el cuento o la poesía; a través del ensayo que reflexiona por sus derechos, por su participación en la política, por su ciudadanía. Una voz que cuestiona y rechaza las imposiciones del sistema patriarcal, los roles, el sexismo y las relaciones interpersonales basadas en la violencia y la subordinación. A través de los diferentes textos, sus autoras realizan una invitaci...

  1. Las Meninas transmedial

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    2001-01-01

    might consist in extending the range of the ‘sample’, both to take in specific media and to cross their borders – and in taking seriously such artistic practice as founds on reproduction technology, doing them justice in our investigations. Meanwhile, trans-media interpretations of works of art created...... as a consequence. The approach of the presented monograph differs, while tentatively adopting certain elements of these approaches, from using Las Meniñas as an example to describe a possible trans-media point of view (Las Meniñas becoming not just a res interpretanda, but a [trans-media] instance for comparison...

  2. Las buenas costumbres

    Directory of Open Access Journals (Sweden)

    Alberto Montezuma Hurtado

    1982-04-01

    Full Text Available Casos suelen suceder en que la información del lector brilla por su solidez y su abundancia, siendo entonces inválido el interés del escritor por presentarle problemas y situaciones para su conocimiento, reflexión y buen consejo. En el caso presente, me parece que huelga todo comentario y que pintar la realidad y exponer las preocupaciones que de ella se desprenden, no sería más que una impertinencia y no quiero incurrir en ella a sabiendas de que el lector no ignora que hace mucho tiempo acabaron en Colombia las buenas costumbres.

  3. Las competencias emocionales

    OpenAIRE

    Rafael Bisquerra Alzina; Núria Pérez Escoda

    2007-01-01

    El concepto de competencia está en revisión debido a su complejidad. Hay diversas categorías de competencias: técnicas, profesionales, participativas, personales, básicas, clave, genéricas, transferibles, emocionales, socio-emocionales, etc. En este trabajo se toman en consideración las competencias emocionales, entendidas como un subconjunto de las competencias personales. Se exponen los trabajos en torno a estas competencias y se aporta una conceptualización y una sistemática...

  4. Analizar las interacciones virtuales

    Directory of Open Access Journals (Sweden)

    Luis Gómez Encinas

    2003-11-01

    Full Text Available El propósito de este artículo es abordar una serie de cuestiones relacionadas con las interacciones virtuales. En concreto, nos centraremos en el IRC, los comúnmente llamados chats, para a partir de una crítica a ciertos posicionamientos analíticos, expresar la necesidad de indagar en esa faceta del ciberespacio desde el punto de vista de las relaciones sociales. Nuevas relaciones sociales, que acontecen en un espacio nuevo, y que por tanto se desarrollan bajo reglas y motivaciones que desbordan los viejos esquemas de observación.

  5. Los cuidados y las mujeres en las familias Los cuidados y las mujeres en las familias

    Directory of Open Access Journals (Sweden)

    María Teresa Martín Palomo

    2008-12-01

    Full Text Available This article proposes a reflection on a debate that is generating an important theorical and empirical production: the care. In the first place, the specificity of care is explored from a point of view that includes, besides the material aspects, affective and moral ones. It stands out the complexity of care at the different dimensions that operate in this concept. Second: care is changing in our society, starting from the massive and durable arrival of women to the labor market. In the families women are mainly responsible or caring for aged population, children and other fragile people. As to this moment care has not been reorganized among the genders, they have been the women of different generations who have articulated its solidarities with available state help or appealing to the market to cover the necessities of its relatives. Howevwe, the graving deficit in the provision of family care seems to approach a point of not sustainability in the near future. Propoal of “social care” offer institutional articulation between private solidarities and public duties in the allotment of family care so tha society in general can bear to the participation of women in the labour work. This implying the return of moral responsibility in the politics of care.Este artículo propone una reflexión sobre uno de los debates que está generando una importante producción teórica y empírica en los últimos años: los cuidados. Para ello, en primer lugar, se explora la especificidad de los cuidados ampliando el enfoque desde un punto de vista que incluya, además de los aspectos materiales, aspectos afectivos y morales. Se destaca la transversalidad y enorme complejidad de los cuidados por las diferentes dimensiones que operan en dicho concepto. En segundo lugar, se revisa como se están reestructurando los cuidados en nuestra sociedad a partir de las transformaciones que ha provocado la llegada masiva y duradera de mujeres al mercado laboral, a la par

  6. Las TIC como fuente de ventaja competitiva en las PYMES

    OpenAIRE

    Álvaro Fernando Moncada Niño; Martha Lucía Oviedo Franco

    2013-01-01

    Desde su aparición, las Tecnologías de la Información y las Comunicaciones (TIC) se han convertido en un recurso fundamental de las empresas para competir en la mayoría de las industrias, generalizando el planteamiento de que son fuente de ventaja competitiva. Pero realmente, ¿cuándo las TIC son fuente potencial de ventaja competitiva para las pymes? ¿Bajo qué condiciones se logra que contribuyan a generar valor y mejorar su posición competitiva? ¿Qué características deben cumplir para alcanz...

  7. Las guerras de Marruecos

    OpenAIRE

    Ramos Oliver, Francisco

    2013-01-01

    En la Historia Militar de España ocupan un lugar importante las campañas mantenidas por sus ejércitos en el territorio de Marruecos, con notables repercusiones en la política interna de nuestra Patria y cuyas consecuencias llegan hasta nuestros día

  8. Sala de las tortugas

    OpenAIRE

    Jiménez Fuentes, Emiliano

    2008-01-01

    [ES] La Sala de las Tortugas, situada actualmente en la Facultad de Ciencias, celebró en 2008 su XX Aniversario, lo que ha servido para motivar con nuevo impulso su quehacer educativo. [EN] The Turtle Room, currently located in the Faculty of Sciences, celebrated its twentieth anniversary in 2008, which has served to motivate new impetus to its educational work.

  9. de las mujeres

    Directory of Open Access Journals (Sweden)

    Elena Margarita Cacheux Pulido

    2003-01-01

    Full Text Available El feminismo chicano tiene múltiples venas que nutrieron el pensamiento ideológico, político y estratégico durante todo el siglo pasado. Una de ellas se forma por los encuentros locales, nacionales e internacionales que sirvieron de plataforma para comunicar, entre mujeres, las propias necesidades para el desarrollo y la liberación de la injusticia, intolerancia y desdén. Las mujeres han luchado por medio de sindicatos y movimientos sociales para plantear justas demandas, entre otras, educación, igual salario por igual trabajo, bienestar, permiso de maternidad, cuidado infantil, autodeterminación, información sexual, igualdad en la participación política y liderazgo. Con el avance teórico en las cuestiones de raza, clase, minorías étnicas y feminismo lésbico, se desarrolló la identidad de la nueva chicana a la luz de la emancipación de las mujeres.

  10. Las competencias emocionales

    Directory of Open Access Journals (Sweden)

    Rafael Bisquerra Alzina

    2007-01-01

    Full Text Available El concepto de competencia está en revisión debido a su complejidad. Hay diversas categorías de competencias: técnicas, profesionales, participativas, personales, básicas, clave, genéricas, transferibles, emocionales, socio-emocionales, etc. En este trabajo se toman en consideración las competencias emocionales, entendidas como un subconjunto de las competencias personales. Se exponen los trabajos en torno a estas competencias y se aporta una conceptualización y una sistemática estructurada en cinco grandes bloques: conciencia emocional, regulación emocional, autonomía emocional, competencia social, habilidades de vida y bienestar. Se hace referencia a las aplicaciones de las competencias emocionales en la empresa, la salud y la educación. De cara a la clarificación de conceptos, se establece la distinción entre inteligencia emocional, competencia emocional y educación emocional.

  11. Droplet Vaporization In A Levitating Acoustic Field

    Science.gov (United States)

    Ruff, G. A.; Liu, S.; Ciobanescu, I.

    2003-01-01

    Combustion experiments using arrays of droplets seek to provide a link between single droplet combustion phenomena and the behavior of complex spray combustion systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together before the combustion event. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. To eliminate the effect of the fiber, several researchers have conducted microgravity experiments using unsupported droplets. Jackson and Avedisian investigated single, unsupported drops while Nomura et al. studied droplet clouds formed by a condensation technique. The overall objective of this research is to extend the study of unsupported drops by investigating the combustion of well-characterized drop clusters in a microgravity environment. Direct experimental observations and measurements of the combustion of droplet clusters would provide unique experimental data for the verification and improvement of spray combustion models. In this work, the formation of drop clusters is precisely controlled using an acoustic levitation system so that dilute, as well as dense clusters can be created and stabilized before combustion in microgravity is begun. While the low-gravity test facility is being completed, tests have been conducted in 1-g to characterize the effect of the acoustic field on the vaporization of single and multiple droplets. This is important because in the combustion experiment, the droplets will be formed and

  12. Condensation of acetol and acetic acid vapor with sprayed liquid

    Science.gov (United States)

    A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid (AA) from flasks on a hot plate. The liquid in the flasks was infused with heated nitrogen. The vapor/nitrogen stream was superheated in a tube oven and condensed by contact with a cloud of ...

  13. Operating a radio-frequency plasma source on water vapor.

    Science.gov (United States)

    Nguyen, Sonca V T; Foster, John E; Gallimore, Alec D

    2009-08-01

    A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires n(i) approximately = n(e), where n(i) is the positive ion density. But in the electronegative water plasma, quasineutrality requires n(i+) = n(i-) + n(e). The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

  14. Bionanomaterials and Bioinspired Nanostructures for Selective Vapor Sensing

    Science.gov (United States)

    2013-04-03

    Shvartsman, B. Dkhil, and A.L. Kholkin 423 Nanowire Heterostructures ...inorganic nanowires , semiconducting conjugated polymer nanotubes, and metal nanoparticles. Vapor sensing with bioinspired nanostructures also brings...Sorption of vapors in insulating regions, electron tunneling between metal cores, charge hopping along the atoms of ligand shell 22, 23 Carbon nanotubes

  15. Vapor Pressure of Bis-(2-chloroethyl)ethylamine (HN1)

    Science.gov (United States)

    2013-10-01

    The spectra that were obtained to compute the vapor-phase absorptivity coefficient showed traces of water vapor that purged during the first day of... barometer . Bath temperature, gas flow rate, and ambient pressure were recorded at 4 s intervals using a National Instruments (Austin, TX) LabVIEW

  16. Isobaric vapor-liquid equilibria of water + ethanol + hexyl acetate

    Energy Technology Data Exchange (ETDEWEB)

    Arce, A.; Soto, A. [Univ. of Santiago de Compostela (Spain). Chemical Engineering Dept.; Orge, B.; Tojo, J. [Univ. of Vigo (Spain). Chemical Engineering Dept.

    1995-09-01

    The authors determined the isobaric vapor-liquid equilibrium data for the ternary system water + ethanol + hexyl acetate at 101.325 kPa using a distillation apparatus recycling both liquid and vapor phases. The results were compared with those predicted using group contribution methods. The UNIFAC method gave the best predictions.

  17. Water vapor and Gas Transport through Polymeric Membranes

    NARCIS (Netherlands)

    Metz, S.J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

  18. Acute toxicity of the vapors of some methylated hydrazine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, K.H.; Clem, J.H.; Wheelwright, H.J.; Rhinehart, W.E.; Mayes, N.

    1955-01-01

    Methylhydrazine, asym-dimethylhydrazine, and sym-dimethylhydrazine vapors are similar to hydrazine in that they are respiratory irritants an;d convulsants on acute exposure. In addition to causing respiratory distress and convulsions, methylhydrazine vapor was found to produce hemolysis and elevated temperatures in exposed dogs. Methylhydrazine was the most toxic of the vapors tested, and hydrazine the least toxic. The higher volatility of asym-dimethylhydrazine indicates that the hazard of this vapor is similar to methylhydrazine. However, the hemolytic properties of methylhydrazine indicate that this vapor has a greater sublethal hazard. Preliminary data on sym-dimethylhydrazine suggest that this vapor has a toxicity and vapor hazard that is less than methylhydrazine and asym-dimethylhydrazine but greater than hydrazine. The odors of hydrazine, methylhydrazine, and asym-dimethylhydrazine were usually described by human subjects as ammoniacal, fishy, or amine-like. The odor of these vapors appears to offer adequate warning of acute exposure to dangerous aspirations. 16 references, 2 figures, 7 tables.

  19. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  20. Spectroscopic observation of copper vapor laser

    Science.gov (United States)

    Ueguri, Shigeo; Hara, Kazuhiko; Iwata, Akihiko; Ueda, Yoshihiro; Tabata, Norikazu

    Time-resolved spectrograms of a Cu-vapor laser plasma were obtained. The discharge was generated in Ne or He buffer gas within an Al2O3 ceramic tube. The electrodes were Mo tubes. The observations were made over the wavelength range from 200 to 650 nm. The spectra from the discharge plasma were mainly composed of Cu I and Ne I or He I. Molecular lines, Na D lines, and H Balmer lines were also observed. From the Inglis-Teller formula applied to the observed H Balmer lines, the average electron density was estimated at about 10 to the 14th/cu cm. The time-resolved spectrograms were obtained with a spectrometer and a boxcar averager during several tens of microsecs after the initiation of pulse discharge.

  1. Chemical vapor deposition of group IIIB metals

    Science.gov (United States)

    Erbil, A.

    1989-11-21

    Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula given in the patent where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula 1 is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula 1 and a heat decomposable tellurium compound under nonoxidizing conditions.

  2. Toxicology of petroleum naphtha distillate vapors.

    Science.gov (United States)

    Wilson, F W

    1976-12-01

    A unique opportunity was presented to observe the potentially toxic effects of an acute exposure to the vapors of petroleum naphtha distillate on a relatively large number of individuals. The immediate manifestation in all was dyspnea. The action on motor vehicle combustion suggested that some of this could have been due to oxygen deprivation; however, all individuals were dyspneic for several minutes after exposure. A few were cyanotic for several minutes after exposure. All were excited. Tremulousness and mild nausea followed the initial symptoms but were of brief duration. One individual manifested numerous premature ventricular contractions. Since his exposure was brief and since none of the others showed similar findings, it is unlikely that the exposure was causal. The central nervous system depression described in acute exposure cases of the intact (not distillate) petroleum naphtha fumes was not observed in any of this series. There were no delayed manifestations or complications.

  3. Water vapor sorption hysteresis of ceramic bricks

    Science.gov (United States)

    Koronthalyova, Olga

    2016-07-01

    A quantification of the hysteretic effects and their thorough analysis was carried out for three types of ceramic bricks. Water vapor adsorption/desorption isotherms were measured by the standard desiccator method. The desorption measurements were carried out from capillary moisture content as well as from equilibrium moisture content corresponding to the relative humidity of 98 %. For all three tested types of bricks the hysteretic effects were present but their significance differed depending on the particular type of brick. Significant differences were noticed also in desorption curves determined from capillary moisture content and from equilibrium moisture content corresponding to the relative humidity of 98 %. Based on the measured data a possible correlation between pore structure parameters and noticed hysteretic effects as well as relevance of the open pore model are discussed. The obtained adsorption/desorption curves were approximated by an analytical relation.

  4. Esquema de análisis para el cálculo del equilibrio líquido vapor de sistemas binarios asimétricos que contienen dióxido de carbono a altas presiones = Schematic analysis for the calculation of vapor liquid equilibrium for asymmetric binary systems containing carbon dioxide at high pressures

    OpenAIRE

    Trejos Montoya, Victor Manuel

    2010-01-01

    El presente trabajo establece el desarrollo de un esquema de análisis del equilibrio líquido vapor de sistemas binarios asimétricos que contienen dióxido de carbono a altas presiones. Dicho esquema integra el ajuste de parámetros del equilibrio líquido vapor, análisis de funciones objetivo, reglas de mezclado EOS-Gex y consistencia termodinámica de este tipo de mezclas con el fin de mejorar las etapas de diseño y la puesta en marcha de equipos que operan con fluidos supercríticos / Abstrac...

  5. Scavenging dissolved oxygen via acoustic droplet vaporization.

    Science.gov (United States)

    Radhakrishnan, Kirthi; Holland, Christy K; Haworth, Kevin J

    2016-07-01

    Acoustic droplet vaporization (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that vaporization of a liquid droplet results in a gas microbubble with a diameter 5-6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional pressures lower than and greater than the ADV pressure amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial pressures of gases at equilibrium, was developed. At insonation pressures exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation pressures, dropping as low as 25% of air saturation within 20s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration gradients can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Chemical vapor deposition coating for micromachines

    Energy Technology Data Exchange (ETDEWEB)

    MANI,SEETHAMBAL S.; FLEMING,JAMES G.; SNIEGOWSKI,JEFFRY J.; DE BOER,MAARTEN P.; IRWIN,LAWRENCE W.; WALRAVEN,JEREMY A.; TANNER,DANELLE M.; DUGGER,MICHAEL T.

    2000-04-21

    Two major problems associated with Si-based MEMS devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, the authors will present a process used to selectively coat MEMS devices with tungsten using a CVD (Chemical Vapor Deposition) process. The selective W deposition process results in a very conformal coating and can potentially solve both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through silicon reduction of WF{sub 6}, which results in a self-limiting reaction. The selective deposition of W only on polysilicon surfaces prevents electrical shorts. Further, the self-limiting nature of this selective W deposition process ensures the consistency necessary for process control. Selective tungsten is deposited after the removal of the sacrificial oxides to minimize process integration problems. This tungsten coating adheres well and is hard and conducting, requirements for device performance. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release stuck parts that are contacted over small areas such as dimples. Results from tungsten deposition on MEMS structures with dimples will be presented. The effect of wet and vapor phase cleanings prior to the deposition will be discussed along with other process details. The W coating improved wear by orders of magnitude compared to uncoated parts. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable.

  7. Thermodynamic Analysis of Combined Vapor Compression and Vapor Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)

    AAMIR SHAIKH

    2017-07-01

    Full Text Available Two of the popular refrigeration cycles, VC (Vapor Compression, and VA (Vapor Absorption are used extensively for refrigeration purposes. In this paper, a system is proposed that works using both cycles powered by an IC (Internal Combustion engine, where mechanical energy is used to run the VC cycle while exhaust gasses are used to operate the VA cycle. The VC cycle works on R12 refrigerant while LiBr-H2O combination is selected for operation of VA cycle. Firstly, the refrigeration system is modeled, followed by a parametric study to investigate the impacts of various operating parameters on the system performance. The results exhibit that for maximum chilling and overall performance, the condenser and evaporator pressures in the VC cycle are obtained as 710 and 340 kPa, respectively, whereas generator and absorber temperatures in VA cycle are 85 and 20oC, respectively

  8. Hybrid Vapor Compression Adsorption System: Thermal Storage Using Hybrid Vapor Compression Adsorption System

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-04

    HEATS Project: UTRC is developing a new climate-control system for EVs that uses a hybrid vapor compression adsorption system with thermal energy storage. The targeted, closed system will use energy during the battery-charging step to recharge the thermal storage, and it will use minimal power to provide cooling or heating to the cabin during a drive cycle. The team will use a unique approach of absorbing a refrigerant on a metal salt, which will create a lightweight, high-energy-density refrigerant. This unique working pair can operate indefinitely as a traditional vapor compression heat pump using electrical energy, if desired. The project will deliver a hot-and-cold battery that provides comfort to the passengers using minimal power, substantially extending the driving range of EVs.

  9. Numerical simulation of superheated vapor bubble rising in stagnant liquid

    Science.gov (United States)

    Samkhaniani, N.; Ansari, M. R.

    2017-09-01

    In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

  10. Pretreated Butterfly Wings for Tuning the Selective Vapor Sensing

    Directory of Open Access Journals (Sweden)

    Gábor Piszter

    2016-09-01

    Full Text Available Photonic nanoarchitectures occurring in the scales of Blue butterflies are responsible for their vivid blue wing coloration. These nanoarchitectures are quasi-ordered nanocomposites which are constituted from a chitin matrix with embedded air holes. Therefore, they can act as chemically selective sensors due to their color changes when mixing volatile vapors in the surrounding atmosphere which condensate into the nanoarchitecture through capillary condensation. Using a home-built vapor-mixing setup, the spectral changes caused by the different air + vapor mixtures were efficiently characterized. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by atomic layer deposition and by ethanol pretreatment can significantly alter the optical response and chemical selectivity, which points the way to the efficient production of sensor arrays based on the knowledge obtained through the investigation of modified butterfly wings.

  11. Historia de las Universidades.

    Directory of Open Access Journals (Sweden)

    Jaime Escobar Triana

    1999-04-01

    ínicos”

    La civilización medieval produjo los arquetipos y el impulso dinámico para las fuerzas principales del mundo moderno. Representa el período de gestación de la cultura moderna. La ciencia occidental se desarrolló en las redes de la erudición medieval que en el siglo XII eran las escuelas catedralicias. La catedral de Chartres, simboliza, históricamente los comienzos de nuestra era científica y tecnológica.

    En la escuela de Chartres se establecieron las bases filosóficas para el surgimiento de la ciencia medieval y la moderna. El estudio de la naturaleza se constituyó en disciplina por derecho propio. En Chartres, durante el siglo XII, el estudio de la ciencia obtuvo por primera vez una prioridad definitiva sobre la enseñanza de las artes liberales y los maestros lucharon por la instauración de osadas reformas en la educación superior general centrando el programa de estudios de ciencias naturales en el cuadrivio: aritmética, música (como matemáticas geometría y astronomía y no en las humanidades tradicionales del trivio: gramática, retórica y lógica.

    La escuela de Chartres desafiaba así a los 7 siglos de enseñanzas cristianas a cerca del lugar de la naturaleza en el esquema divino, contra todas las resistencias de las grandes escuelas catedralicias de Orleans, Saint Victor en París y Laon. El ser humano y el mundo eran una unidad en el pensamiento de Chartres; trivio y cuadrivio eran parte de un universo único. Pedro Abelardo En sus escritos (siglo XII se hallan las raíces históricas de la técnica, del método con el que las grandes escuelas universitarias del S XIII construyeron, organizaron y expresaron sus doctrinas, las síntesis teológicas más complejas y más completas de la edad media. Abelardo en la Escuela de Santa Genoveva en París y Cátedra de Notre-Dame, Busca huir de los condicionamientos de las estructuras culturales cerradas e inmóviles y de las rígidas concepciones tradicionales para abrirse a una vía de investigaci

  12. High School Students’ Use of Electronic Cigarettes to Vaporize Cannabis

    Science.gov (United States)

    Kong, Grace; Camenga, Deepa R.; Cavallo, Dana A.; Krishnan-Sarin, Suchitra

    2015-01-01

    BACKGROUND AND OBJECTIVES: Electronic cigarette (e-cigarette) use is increasing rapidly among high school (HS) students. Of concern, e-cigarettes can be used to vaporize cannabis, although use rates among adolescents are unknown. We evaluated lifetime rates of using e-cigarettes to vaporize cannabis among all lifetime e-cigarette users (27.9%), all lifetime cannabis users (29.2%), and lifetime users of both e-cigarettes and cannabis (18.8%); common means of vaporizing cannabis including hash oil, wax infused with Δ-9-tetrahydrocannabinol (THC), and dried cannabis; and demographic predictors of using e-cigarettes to vaporize cannabis. METHODS: In the spring of 2014, 3847 Connecticut HS students completed an anonymous survey assessing e-cigarette and cannabis use. RESULTS: Vaporizing cannabis using e-cigarettes was common among lifetime e-cigarette users, lifetime cannabis users, and lifetime dual users (e-cigarette 18.0%, cannabis 18.4%, dual users 26.5%). Students reported using e-cigarettes to vaporize hash oil (e-cigarette 15.4%, cannabis 15.5%, dual users 22.9%) and wax infused with THC (e-cigarette 10.0%, cannabis 10.2%, dual users 14.8%) and using portable electronic vaporizers to vaporize dried cannabis leaves (e-cigarette 19.6%, lifetime cannabis 23.1%, lifetime dual users 29.1%). Binary logistic regression indicated that male students (odds ratio [OR] = 2.05), younger students (OR = 0.64), lifetime e-cigarette users (OR = 5.27), and lifetime cannabis users (OR = 40.89) were most likely to vaporize cannabis using e-cigarettes. Rates also differed by HS attended. CONCLUSIONS: Rates of vaporizing cannabis using e-cigarettes were high. These findings raise concerns about the lack of e-cigarette regulations and the potential use of e-cigarettes for purposes other than vaping nicotine. PMID:26347431

  13. High School Students' Use of Electronic Cigarettes to Vaporize Cannabis.

    Science.gov (United States)

    Morean, Meghan E; Kong, Grace; Camenga, Deepa R; Cavallo, Dana A; Krishnan-Sarin, Suchitra

    2015-10-01

    Electronic cigarette (e-cigarette) use is increasing rapidly among high school (HS) students. Of concern, e-cigarettes can be used to vaporize cannabis, although use rates among adolescents are unknown. We evaluated lifetime rates of using e-cigarettes to vaporize cannabis among all lifetime e-cigarette users (27.9%), all lifetime cannabis users (29.2%), and lifetime users of both e-cigarettes and cannabis (18.8%); common means of vaporizing cannabis including hash oil, wax infused with Δ-9-tetrahydrocannabinol (THC), and dried cannabis; and demographic predictors of using e-cigarettes to vaporize cannabis. In the spring of 2014, 3847 Connecticut HS students completed an anonymous survey assessing e-cigarette and cannabis use. Vaporizing cannabis using e-cigarettes was common among lifetime e-cigarette users, lifetime cannabis users, and lifetime dual users (e-cigarette 18.0%, cannabis 18.4%, dual users 26.5%). Students reported using e-cigarettes to vaporize hash oil (e-cigarette 15.4%, cannabis 15.5%, dual users 22.9%) and wax infused with THC (e-cigarette 10.0%, cannabis 10.2%, dual users 14.8%) and using portable electronic vaporizers to vaporize dried cannabis leaves (e-cigarette 19.6%, lifetime cannabis 23.1%, lifetime dual users 29.1%). Binary logistic regression indicated that male students (odds ratio [OR] = 2.05), younger students (OR = 0.64), lifetime e-cigarette users (OR = 5.27), and lifetime cannabis users (OR = 40.89) were most likely to vaporize cannabis using e-cigarettes. Rates also differed by HS attended. Rates of vaporizing cannabis using e-cigarettes were high. These findings raise concerns about the lack of e-cigarette regulations and the potential use of e-cigarettes for purposes other than vaping nicotine. Copyright © 2015 by the American Academy of Pediatrics.

  14. Historia de las Hormonas

    Directory of Open Access Journals (Sweden)

    Alfredo Jácome-Roca

    2009-01-01

    Full Text Available

    El historiador Garrison afirma en su libro Introducción a la Historia de la Medicina que… “la nueva ciencia de la endocrinología, aunque arraigada en el pasado prehistórico, es virtualmente una creación del siglo XX…”

    Eso es precisamente lo que se quiere mostrar en este libro: las raíces hundidas en el pasado y los sorprendentes hallazgos de la modernidad de la centuria precedente, con algunos hechos importantes acaecidos en el siglo XIX.

    Los primeros datos conocidos comenzaron por las observaciones sobre animales y humanos castrados, sobre gigantes y enanos, diabéticos, cotudos y cretinos, y luego sobre las descripciones incipientes de los órganos endocrinos más grandes como el cuerpo tiroides, las cápsulas suprarrenales, testículos, ovarios y la glándula pituitaria. Personajes que podrían perfectamente provenir del país de Lilliput o de un circo del vecindario, tal era su extraña apariencia.

    Una eventual relación entre los casos clínicos mencionados y las glándulas se ignoraba casi totalmente, casi porque sí se sabía lo que ocurría a un animal o a un hombre castrado, antes y después de la pubertad. Por eso nos detendremos en algunas anécdotas (imposible la historia completa de los eunucos (y por espacio de dos siglos, particularmente en Italia, de los hombres-soprano denominados los castrati.

    Persistía la incógnita sobre la función de ciertos órganos o tejidos –llamados por siglos glándulas sin conducto (incluídos órganos hematopoyéticos como el timo, el bazo o los ganglios linfáticos: una pituitaria productora de moco, que drenaba en las fosas nasales el moco excesivo que se producía en los catarros; o una tiroides que lubricaba la laringe, unas cápsulas suprarrenales que sostenían los riñones, unos ovarios que eran testículos femeninos, o unos testículos que –esos sí- regaban semilla en el útero de las mujeres. Y tambi

  15. Las organizaciones complejas

    Directory of Open Access Journals (Sweden)

    Julio Mario Rodríguez Devis

    2002-05-01

    Full Text Available El aproximarse a las organizaciones con la visión de la complejidad permite observar sus múltiples interrelaciones, la relación orden-desorden-relaciones-retroacciones que se desarrollan en su interior, la íntima influencia bi-direccional entre el entorno y la organización, la emergencia y la autoorganizacion, la importancia de la información-ruido; en fin, observar a la organización como un sistema dinámico, no lineal, abierto y complejo. En este artículo se presentan los fundamentos de la complejidad en las organizaciones, y se describen los principales elementos que la constituyen.

  16. Las declinaciones del aura

    Directory of Open Access Journals (Sweden)

    Cecilia Bettoni

    2016-11-01

    Full Text Available Habitualmente, asociamos el concepto benjaminiano de aura a una cualidad de la obra de arte que desfallece con el creciente desarrollo de las técnicas mecánicas de reproducción. Sin embargo, el mismo Benjamin señala que este desfallecimiento es un proceso sintomático, cuyo significado desborda el dominio puramente artístico. En este contexto, el presente artículo indaga este desborde a partir de la elasticidad que la noción de aura alcanza en la obra de Walter Benjamin, con el objeto de demostrar que este concepto no constituye un elemento privativo de las obras de arte, sino que se refiere más bien a cierta modulación de la experiencia histórica y estética

  17. Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

    Science.gov (United States)

    The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step,...

  18. Humanismo en las universidades

    Directory of Open Access Journals (Sweden)

    Carlos Arturo Caparroso

    1963-08-01

    Full Text Available Algunas universidades del país, con encomiable acierto, han establecido, en los programas de sus ciclos de enseñanza profesional, el estudio de asignaturas de cultura general. Y para prestigiarlas, las han rotulado con una denominación ciertamente esclarecida y grata, término de rancia prosapia, de insigne lastre histórico: humanidades.

  19. Derrida en las pampas

    Directory of Open Access Journals (Sweden)

    Analía Gerbaudo

    2011-07-01

    Full Text Available http://dx.doi.org/10.5007/1984-784X.2011v11n16p16 En el año 2003 Mariano Ben Plotkin publica Freud en las pampas. Orígenes y desarrollo de una cultura psicoanalítica en la Argentina (1910-1983: un estudio minucioso de la recepción y difusión del psicoanálisis que recupero tanto en sus aspectos metodológicos como en sus conjeturas sobre la relación que los intelectuales argentinos suelen entablar con el pensamiento europeo (tesis que se refuerzan si se las lee en conjunción con las desarrolladas respecto de lo que ha acontecido en el campo de los estudios literarios en nuestro país entre la segunda mitad del siglo XX hasta la fecha –cf. Gerbaudo, 2006a, 2007a, 2007b-. Plotkin pone la descripción de la masiva difusión del psicoanálisis en Argentina en el corte temporal seleccionado al servicio del estudio de los factores culturales, sociales y políticos que hicieron lugar a esa acogida.

  20. LAS ENFERMEDADES RARAS

    Directory of Open Access Journals (Sweden)

    Fanny Cortés M. Dra.

    2015-07-01

    Full Text Available A partir de la década de los 80, las enfermedades raras han ido adquiriendo un lugar prioritario en los programas de salud y en la opinión pública. Se definen como aquellas que tienen una prevalencia menor a 1:2.000 individuos. En general son enfermedades crónicas, invalidantes y en más de un 80% de origen genético. Se estima que existen entre 7.000 y 8.000 enfermedades raras y que afectan al 6-8% de la población. Dada la baja prevalencia específica de cada afección, hay muy poco conocimiento de parte de la comunidad médica en relación a su diagnóstico y manejo. En este artículo se discute la importancia del diagnóstico de precisión, para su adecuado manejo y asesoramiento genético, también se muestra la importancia del trabajo en redes en las enfermedades de baja prevalencia y se destaca el rol fundamental de las agrupaciones de padres y familiares en promover políticas de salud para los afectados.

  1. Las Violencias contra las Mujeres en una Sociedad en Guerra

    OpenAIRE

    Sánchez Gómez, Olga Amparo

    2008-01-01

    Las violencias contra las mujeres exceden los acontecimientos violentos, y abarcan su producción y reproducción como fenómeno social y discursivo. Los hechos violentos y los discursos sobre la violencia aparecen entrelazados, especialmente si se piensa en papel que juega la cultura patriarcal en el desarrollo, perpetuación y validación de las violencias contra las mujeres. “A las mujeres nos violan, nos asaltan y nos golpean, nos ultrajan, nos humillan, nos deshumanizan, nos manosean, nos ase...

  2. Las Brigadas Internacionales

    Directory of Open Access Journals (Sweden)

    Manuel REQUENA GALLEGO

    2015-03-01

    Full Text Available La presencia en España de unos 35.000 voluntarios, reclutados por la Tercera Internacional, consiguió que ciudadanos de más de 53 países cooperaran con el Ejército Popular de la República durante la Guerra Civil. La historia de las Brigadas ha generado desde 1996 a esta fecha una literatura en rápido crecimiento. Las Brigadas Internacionales se han estudiado desde muchas perspectivas. Este artículo aborda el amplio panorama de libros desglosándolos en seis áreas. Hemos referenciado 168 títulos publicados entre 2006 y 2013 y los hemos analizado estadísticamente desde el punto de vista de su idioma, lugar de aparición, año y temática principal. En lo que se refiere al idioma un 73% se escribieron en español, un 10% en inglés, un 5% en catalán, un 4% en italiano, un 4% en francés y un 4% en otras lenguas. Un 82% aproximadamente se publicaron en España y solo 18% en el extranjero. Por fechas, en el año 2009 tuvo lugar el volumen de producción más amplio. Por temas, el porcentaje más elevado lo componen las biografías y memorias. Le siguen el lugar de origen de cada Brigada, aspectos militares generales y las batallas más importantes. A los 75 años casi del final de la Guerra Civil el fenómeno de las Brigadas Internacionales y su significado está más presente que nunca. No solo se ha escrito un considerable número de libros sino que también se han organizado actividades tales como proyecciones de películas y exposiciones para rendir homenaje a los voluntarios extranjeros que vinieron a España a luchar contra Franco.

  3. Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 2. Experimental Validation with Simple Mixtures and Actual Fermentation Broth

    Science.gov (United States)

    BACKGROUND: In Part1 of this work, a process integrating vapor stripping, vapor compression, and a vapor permeation membrane separation step, Membrane Assisted Vapor Stripping (MAVS), was predicted to produce energy savings compared to traditional distillation systems for separat...

  4. Estudio de controlabilidad de un proceso de reformado de etanol con vapor para la producción de hidrógeno

    OpenAIRE

    García, Vanesa M.; Serra, Maria; Llorca, Jordi

    2010-01-01

    En este trabajo hemos modelado un sistema de reformado de etanol con vapor y purificación de monóxido de carbono (CO). Dicho sistema está destinado a alimentar una pila de combustible tipo PEM. A partir del modelo hemos realizado un estudio de sensibilidad y controlabilidad enfatizando la influencia de la temperatura en las variables de salida de interés. Los resultados del estudio de controlabilidad se utilizan para la selección de las estructuras de control más convenientes. ...

  5. Non-equilibrium phenomena near vapor-liquid interfaces

    CERN Document Server

    Kryukov, Alexei; Puzina, Yulia

    2013-01-01

    This book presents information on the development of a non-equilibrium approach to the study of heat and mass transfer problems using vapor-liquid interfaces, and demonstrates its application to a broad range of problems. In the process, the following peculiarities become apparent: 1. At vapor condensation on the interface from gas-vapor mixture, non-condensable components can lock up the interface surface and condensation stops completely. 2. At the evolution of vapor film on the heater in superfluid helium (He-II), the boiling mass flux density from the vapor-liquid interface is effectively zero at the macroscopic scale. 3. In problems concerning the motion of He-II bridges inside capillaries filled by vapor, in the presence of axial heat flux the He-II bridge cannot move from the heater as would a traditional liquid, but in the opposite direction instead. Thus the heater attracts the superfluid helium bridge. 4. The shape of liquid-vapor interface at film boiling on the axis-symmetric heaters immersed in l...

  6. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    Science.gov (United States)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

  7. Bionanomaterials and Bioinspired Nanostructures for Selective Vapor Sensing

    Science.gov (United States)

    Potyrailo, Radislav; Naik, Rajesh R.

    2013-07-01

    At present, monitoring of air at the workplace, in urban environments, and on battlefields; exhaled air from medical patients; air in packaged food containers; and so forth can be accomplished with different types of analytical instruments. Vapor sensors have their niche in these measurements when an unobtrusive, low-power, and cost-sensitive technical solution is required. Unfortunately, existing vapor sensors often degrade their vapor-quantitation accuracy in the presence of high levels of interferences and cannot quantitate several components in complex gas mixtures. Thus, new sensing approaches with improved sensor selectivity are required. This technological task can be accomplished by the careful design of sensing materials with new performance properties and by coupling these materials with the suitable physical transducers. This review is focused on the assessment of the capabilities of bionanomaterials and bioinspired nanostructures for selective vapor sensing. We demonstrate that these sensing materials can operate with diverse transducers based on electrical, mechanical, and optical readout principles and can provide vapor-response selectivity previously unattainable by using other sensing materials. This ability for selective vapor sensing provides opportunities to significantly impact the major directions in development and application scenarios of vapor sensors.

  8. New Regenerative Cycle for Vapor Compression Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Bergander

    2005-08-29

    The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and

  9. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  10. Measurement of alkali vapors in PFBC exhaust. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.

    1994-01-01

    Under the auspices of the US Department of Energy through Morgantown Energy Technology Center, laboratory-scale studies were conducted to develop a regenerable activated-bauxite adsorbent (RABA) for use in an in situ regenerable activated-bauxite sorber alkali monitor (RABSAM). The RABSAM is a sampling probe that does not require a high-temperature/high-pressure sampling line for reliable measurement of alkali vapor in the exhaust of pressurized fluidized-bed combustor (PFBC). The RABA can be generated from the commercial grade activated bauxite by deactivating (or reacting) clay impurities in activated bauxite with NaCl or LiCl vapor. Under the atmospheric deactivation process, however, only a partial deactivation of clay impurities is achieved, probably due to limited access of NaCl or LiCl vapor into micropores of activated bauxite. Because LiCl vapor chemically reacts with alumina substrate of activated bauxite, resulting in pore enlargement, loss of pore surface area, and a decrease in the subsequent NaCl-vapor sorption capacity of the RABA, NaCl is a more suitable deactivation agent than LiCl vapor. In a simulated PFBC exhaust environment, the RABA behaves similarly to fresh activated bauxite in capturing NaCl vapor from the simulated PFBC exhaust. Based on results of this work, we recommend generating chemically and thermally stable RABA by deactivating clay impurities of commercial grade activated bauxite with NaCl or KCl vapor under simulated PFBC exhaust environment, that is, high-temperature, high-pressure, and high concentrations of NaCl or KCl vapor in simulated PFBC exhaust compositions.

  11. Demand management in steam generation?; Administracion de la demanda en la generacion de vapor?

    Energy Technology Data Exchange (ETDEWEB)

    Plauchu L., A.; Plauchu A., J. A. [Ingenieros consultores (Mexico)

    1997-12-31

    Energy management has acquired capital importance in all the branches of the industrial activity and services either private o public and it has been, from years behind, more familiar the technology for the demand control in the electric power distribution systems, with excellent results in the energy conservation and economy. The rate of consumption for the different forms of energy shows the prevalence of the thermal energy in a variety of end uses. Not much or almost nothing has been said of the term Demand Management or Control in Steam Generation although 12% of the total energy supply is used for this purpose. Steam demand management and control can avoid unnecessary investments that bring along the increment of operational and maintenance problems and it is for sure that it will always give raise to a more rational and economical utilization of the real capacity of steam generation. A real case is commented. [Espanol] La administracion de la energia ha cobrado importancia capital en todos los giros de actividad industrial y de servicios, privados y publicos y es de varios anos atras cada vez mas familiar la tecnologia en el control de demanda en los sistemas de distribucion de energia electrica, con magnificos resultados en el ahorro, energetico y economico. La relacion de consumos para las diferentes formas de energia muestra el predominio de la energia termica en una variedad de usos finales. Poco o nada oimos del termino Administracion o Control de Demanda en la Generacion de Vapor aun cuando el 12% de la oferta total de energia tiene como destino esta aplicacion. La administracion y control de la demanda de vapor puede evitar inversiones innecesarias e incremento de problemas de operacion y mantenimiento y con seguridad reportaran siempre una utilizacion mas racional y economica de la capacidad real de generacion de vapor, se comenta un caso real.

  12. CONCENTRAÇÃO DE VAPOR D'ÁGUA NA ATMOSFERA DE ÁREAS URBANAS, SÃO PAULO/BRASIL

    Directory of Open Access Journals (Sweden)

    Denis Dorighello Tomás

    2012-01-01

    Full Text Available En este trabajo se hace un estudio del contenido de vapor de agua en la atmósfera en áreas urbanas y las implicaciones de estas para con este elemento constituyente de la atmósfera, teniendo como área de estudio la área urbanizada de São Paulo. El vapor de agua es lo principal elemento natural existente en la atmósfera responsable por el llamado efecto invernadero, devido su capacidad de almacenar calor. Los estudios sobre el aumento de temperatura global están centrados en los llamados gases de emisión antropogénicas termoactivos en las áreas urbanizadas. Fueran utilizados datos de registros de humedad específica, en razón de ser la manera mas correcta de registro del verdadero contenido de humedad existente en la atmósfera. La investigación identificó tendencia de aumento del contenido de vapor de agua en la atmósfera de la área urbana, siendo su evolución influyenciada por la manifestación de la brisa marítima, evaporación de agua de los embalses y por la urbanización. Todavía no deja de estar subordinado a las condiciones mesoclimáticas que vigoran en la región.

  13. Las marcas propias en Colombia

    Directory of Open Access Journals (Sweden)

    Carlos Felipe Payán Rodríguez

    2013-11-01

    Full Text Available El artículo analiza la situación actual de las marcas propias en Colombia, teniendo en cuenta su creciente auge al interior de las grandes superficies. Mediante este tipo de marcas el mismo distribuidor vende productos y servicios con su nombre o recurriendo a una marca de su propiedad, compitiendo con las marcas ya posicionadas en el mercado de los fabricantes. El texto se articula, primero, en una contextualización con base en doctrina comparada respecto de las marcas propias. Luego, se aplican las reglas de dichos conceptos doctrinales a la situación actual colombiana. Por último, se plantean dos problemas jurídicos respecto de las marcas propias, uno, analizado desde la propiedad industrial, y el otro, desde las reglas del Estatuto del Consumidor.

  14. Vaporization Studies of Olivine via Knudsen Effusion Mass Spectrometry

    Science.gov (United States)

    Costa, G. C. C.; Jacobson, N. S.

    2014-01-01

    Olivine is the major mineral in the Earth's upper mantle occurring predominantly in igneous rocks and has been identified in meteorites, asteroids, the Moon and Mars. Among many other important applications in planetary and materials sciences, the thermodynamic properties of vapor species from olivine are crucial as input parameters in computational modelling of the atmospheres of hot, rocky exoplanets (lava planets). There are several weight loss studies of olivine vaporization in the literature and one Knudsen Effusion Mass Spectrometry (KEMS) study. In this study, we examine a forsterite-rich olivine (93% forsterite and 7% fayalite, Fo93Fa7) with KEMS to further understand its vaporization and thermodynamic properties.

  15. Vaporization in Comets; outbursts from Comet Schwassmann-Wachmann 1

    Science.gov (United States)

    Cowan, J. J.; Ahearn, M. F.

    1982-01-01

    Revised estimates are presented which show that the total mass and kinetic energy in a typical Comet P/Schassmann-Wachmann 1 outburst are lower than previously estimated, and that this mass is comparable to the mass of gas vaporized, as inferred from recent observations of CO(+) in this comet. The storage of energy suggested by many authors is therefore not neccessary. A simple equilibrium vaporization of CO2 or CO which is suddenly exposed, on a nucleus that is otherwise primarily composed of H2O, is proposed. Under these conditions, calculations of the variation of vaporization with rotational phase indicate that the mechanism can quantitatively produce outbursts of the size observed.

  16. LOX vaporization in high-pressure, hydrogen-rich gas

    Science.gov (United States)

    Litchford, Ron J.; Jeng, San-Mou

    1990-01-01

    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  17. Mars: Water Vapor Observations from the Viking Orbiters

    Science.gov (United States)

    Farmer, C. B.; Davies, D. W.; Holland, A. L.; Laporte, D. D.; Doms, P. E.

    1977-01-01

    The global distribution of the water vapor has been mapped at low resolution throughout the period from the northern summer solstice to the following equinox. During this seasonal period the water vapor underwent a gradual redistribution, the latitude of maximum column abundance moving from the northern polar area to the equatorial latitudes. The total global vapor content remained approximately constant at the equivalent of about 1.3 cu km of ice. The various data obtained indicate that the residual polar caps are composed of water ice.

  18. Las narcodemocracias andinas

    Directory of Open Access Journals (Sweden)

    Olivier DABÈNE

    2009-11-01

    Full Text Available RESUMEN: Los países de América Latina están afectados en diferentes aspectos por el tráfico de drogas. En especial, en los países andinos, esta actividad ha condicionado de manera decisiva el tipo de régimen democrático iniciado en algún caso en la década de 1980, como Perú o Bolivia, o el régimen colombiano. El autor califica a estos regímenes como narcodemocracias por los efectos del tráfico de drogas no sólo en el orden social y económico, que analiza de forma profunda, sino por la politización del narcotráfico. Las respuestas de las democracias han sido bien distintas en los tres casos analizados, afectando, sin embargo, en todos ellos, a la gobernabilidad de las mismas y a su legitimidad.ABSTRACT: Latin American countries are affected by narcotrafico in different aspects. Particularly, in Andean countries, this activity has deeply conditioned the type of democratic regime installed in some cases in the eighties, as Perou and Bolivia, or the colombian regimen. The author characterizes these regimes as narcodemocracias by effects of narcotrafico in them, not only in social and economic arenas, but also by the politization of narcotrafico. Responses of democracies have been very different in these cases analyzed in the article. Nevertheless, in all of them, governability and legitmity of democracy are affected.

  19. Bongos, champanes y vapores en la navegación fluvial colombiana del siglo XIX

    Directory of Open Access Journals (Sweden)

    Eduardo Posada Carbó

    1989-10-01

    Full Text Available A bordo blanco,  le gritó el patrón del champán a José Joaquín Borda, mientras éste observaba la ancha canoa que lo conduciría a la bodega de Conejo, aquella estación obligada de los vapores que subían por el Magdalena y que, debido a los rápidos del río, no podrían seguir hasta Honda. El viaje de Borda en la Joven Tulia -como se llamaba la embarcación atestada de pacas de tabaco-, en medio de las mercancías y la tradicional algarabía de los bogas, duró seis horas.

  20. Las locas ilusiones

    OpenAIRE

    Mendívil,Julio

    2006-01-01

    Evidentemente vivimos descubriendo la pólvora, pues migración ha habido siempre. No sólo en los renglones míticos del éxodo bíblico ni en la triste ruta errabunda del pithecanthropus, también los desplazamientos de los visigodos por tierras sureñas o los asaltos de los hunos al este de Europa fueron migraciones. Puestos a ver las cosas, el mismo poblamiento del continente americano no fue sino el resultado de consecutivas hordas migratorias asiáticas llegadas al Nuevo Mundo por el estrecho de...

  1. Las escuelas no brillan

    Directory of Open Access Journals (Sweden)

    Rubén Astudillo

    2015-01-01

    Full Text Available El ejercicio de la comunicación se ha convertido en una de las profesiones más necesarias y, a la vez, más peligrosas. El ciudadano quiere estar al tanto de lo que sucede en su entorno. El mensaje del comunicador debe responder a la realidad plena de los acontecimientos. La distorsión puede resultar en situaciones conflictivas, en verdaderos desastres sociales. Esto demanda una personalidad multifacética en el comunicador que no puede ser sino el producto de una formación integral.

  2. Las comunicaciones tributarias

    OpenAIRE

    Martínez Muñoz, Yolanda

    2004-01-01

    La Ley General Tributaria no distingue entre la declaración y la comunicación tributaria, definiendo la primera en su artículo 119 de una forma muy amplia. En este trabajo se realiza un análisis de los distintos supuestos de comunicaciones tributarias regulados en nuestro ordenamiento tributario para concretar, mediante la utilización de un método inductivo, la delimitación conceptual y el régimen jurídico de las comunicaciones tributarias.

  3. Las finanzas personales

    OpenAIRE

    Luis Olmedo Figueroa Delgado

    2013-01-01

    El éxito en la administración de las finanzas personales puede provenir de diversos estamentos, sin embargo, se estructura un elemento esencial que permite tomar decisiones consientes y más coherentes en el quehacer diario, el cual es el “presupuesto”, es por ello que en este articulo artículo se tomara esta herramienta financiera como elemento pivote que cumplirá dos fines principales: El resultado lógico y eficiente de una serie de actividades cotidianas que permite tomar decisiones en bene...

  4. Virtual test bench as a complement to study thermal area: application in vapor compression systems

    Directory of Open Access Journals (Sweden)

    Juan Manuel Belman-Flores

    2015-01-01

    Full Text Available Este artículo describe un simulador educativo desarrollado en el software Engineering Equation Solver para representar el comportamiento de un sistema de compresión de vapor. La aplicación está enfocada con propósitos educativos, particularmente para que estudiantes de ingeniería adquieran habilidades en el manejo de instalaciones de refrigeración. Mediante el uso de este simulador, los estudiantes tendrán la capacidad de analizar fácilmente la infl uencia que tienen parámetros medidos experimentalmente (como la velocidad de rotación del compresor, el fl ujo volumétrico y la temperatura de fl uidos secundarios sobre la efi ciencia energética del sistema y sus componentes principales. El banco virtual consta de una pantalla principal que muestra un esquema general del sistema de compresión de vapor con parámetros de entrada y de salida. Desde la pantalla principal, el desempeño de los componentes principales puede ser analizado. Finalmente, este banco de pruebas virtual ha sido probado por estudiantes de ingeniería, concluyendo que el simulador es una herramienta de apoyo que permite mejorar el aprendizaje de las diferentes áreas del conocimiento.

  5. Vapor-fed microfluidic hydrogen generator.

    Science.gov (United States)

    Modestino, M A; Dumortier, M; Hosseini Hashemi, S M; Haussener, S; Moser, C; Psaltis, D

    2015-05-21

    Water-splitting devices that operate with humid air feeds are an attractive alternative for hydrogen production as the required water input can be obtained directly from ambient air. This article presents a novel proof-of-concept microfluidic platform that makes use of polymeric ion conductor (Nafion®) thin films to absorb water from air and performs the electrochemical water-splitting process. Modelling and experimental tools are used to demonstrate that these microstructured devices can achieve the delicate balance between water, gas, and ionic transport processes required for vapor-fed devices to operate continuously and at steady state, at current densities above 3 mA cm(-2). The results presented here show that factors such as the thickness of the Nafion films covering the electrodes, convection of air streams, and water content of the ionomer can significantly affect the device performance. The insights presented in this work provide important guidelines for the material requirements and device designs that can be used to create practical electrochemical hydrogen generators that work directly under ambient air.

  6. Update on Greenlight laser vaporization (PVP) 2014.

    Science.gov (United States)

    Rieken, Malte; Bachmann, Alexander

    2015-04-01

    To asses the (1) outcomes and (2) intraoperative, perioperative, and long-term complications of photoselective vaporization of the prostate (PVP) with Greenlight laser. A systematic review of outcomes and complications of PVP was conducted. The article selection process was performed according to PRISMA guidelines and included publications published between 2009 and 2014. All generations of PVP (80, 120, 180 W) lead to a significant improvement of micturition symptoms (IPSS, QoL) and voiding parameters (Q max, PVR volume) during follow-up. Data on sexual function are heterogeneous and suggest a trend toward decline in erectile function in men with sustained preoperative erection. The rate of intraoperative complications is low. Data on peri- and postoperative complications show a large variation that mainly can be attributed to heterogeneity in documentation. PVP leads to a statistically significant and clinically relevant improvement of voiding parameters and micturition symptoms in patients with prostates technique is characterized by a high degree of intra- and perioperative safety. Long-term evidence on functional outcomes and complications beyond 3 years from RCTs is currently missing for all generations of the Greenlight laser.

  7. Emission factors for trichloroethylene vapor degreasers.

    Science.gov (United States)

    Wadden, R A; Scheff, P A; Franke, J E

    1989-09-01

    Emission factors were developed for two production trichloroethylene (TCE) vapor degreasers: an open-top (0.76 m x 1.16 m x 1.8 m) and a conveyor-fed enclosed design. Both were fitted with functioning local exhaust hoods. Emissions were determined from field data by using a Fick's law diffusion approach and the observed variation in time of the TCE concentration gradient within 4 m of each device. The average emission factor for the open-top degreaser was 2.6 g TCE/min [2.9 g TCE/(m2.min)] which corresponds to 9.5% of the total degreaser emissions escaping into the workplace. The average emission factor for the enclosed degreaser was 0.67 g TCE/min, a release of 3% of the total emissions into the work area. These values are considered to be representative of the average lower limit of emissions during production from TCE degreasers of like designs with similar local exhaust controls (which were typical but did not meet American Conference of Governmental Industrial Hygienists' [ACGIH] airflow rate criteria).

  8. Characterization of Metalorganic Chemical Vapor Deposition

    Science.gov (United States)

    Jesser, W. A.

    1998-01-01

    A series of experimental and numerical investigations to develop a more complete understanding of the reactive fluid dynamics of chemical vapor deposition were conducted. In the experimental phases of the effort, a horizontal CVD reactor configuration was used for the growth of InP at UVA and for laser velocimetry measurements of the flow fields in the reactor at LaRC. This horizontal reactor configuration was developed for the growth of III-V semiconductors and has been used by our research group in the past to study the deposition of both GaAs and InP. While the ultimate resolution of many of the heat and mass transport issues will require access to a reduced-gravity environment, the series of groundbased research makes direct contributions to this area while attempting to answer the design questions for future experiments of how low must gravity be reduced and for how long must this gravity level be maintained to make the necessary measurements. It is hoped that the terrestrial experiments will be useful for the design of future microgravity experiments which likely will be designed to employ a core set of measurements for applications in the microgravity environment such as HOLOC, the Fluid Physics/Dynamics Facility, or the Schlieren photography, the Laser Imaging Velocimetry and the Laser Doppler Velocimetry instruments under development for the Advanced Fluids Experiment Module.

  9. Acoustic Droplet Vaporization in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Chung-Yin Lin

    2013-01-01

    Full Text Available This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.

  10. (Mol. Stuntz por arrastre de vapor

    Directory of Open Access Journals (Sweden)

    Ximena Araneda

    2014-01-01

    Full Text Available El objetivo del presente estudio fue elaborar y evaluar jugo de maqui (Aristotelia chilensis(Mol. Stuntz, paraser considerado potencialmente como una bebida funcional de origen natural, sin aditivos químicos y mínimoprocesamiento, mediante la técnica de arrastre por vapor de tipo artesanal. Se utilizó fruto recolectado deforma manual en la Región de La Araucanía (Chile. Se elaboraron dos jugos concentrados, con azúcar y sinazúcar. Se realizaron análisis tales como: contenido de sólidos solubles, pH, acidez, contenido de humedad,materia seca (MS, cenizas totales, azúcares totales (AT, proteína cruda (PC, polifenoles totales (PFT ycarbohidratos totales (CHT, destacando el contenido de polifenoles para el jugo sin azúcar con 993,2 mg 100mL-1EAG y para el jugo con azúcar con 829,208 mg 100 mL-1EAG. Por lo tanto, la técnica permite extraerjugo de maqui con un mínimo procesamiento, presentando éste una alta concentración de polifenoles.

  11. Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Kmetz, M.A.

    1992-01-01

    Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

  12. Las carreras del futuro

    Directory of Open Access Journals (Sweden)

    Luis Piscoya Hermoza

    2011-07-01

    Full Text Available La primera década del siglo XXI ha estado signada por un énfasis en los estudiosde prospectiva, los mismos que, a partir de procesos de complejizacióny articulación de la sociedad planetaria como son la digitalización, el progresivodeterioro del medio ambiente, la necesidad del cambio de la matriz energéticay la globalización del mercado, han ensayado hipótesis para identificar lastendencias que se fortalecerán y profundizarán durante las próximas décadas.Desde el punto de vista metodológico, existen muchas maneras de clasificarlaspara conceptualizarlas y entenderlas mejor. Sin embargo, considerando lanaturaleza de esta edición nos proponemos enfocar directamente aquellas queestán estrechamente ligadas a la formación universitaria.Naturalmente, no pensamos que estamos ante tendencias inevitables en lamedida que epistemológicamente la creencia en leyes históricas deterministases insostenible y la práctica social nos muestra que la construcción del futuroes nuestra responsabilidad y siempre rebasa las mejores previsiones.

  13. Las crisis familiares

    Directory of Open Access Journals (Sweden)

    Idarmis González Benítez

    2000-06-01

    Full Text Available Con este trabajo nos propusimos actualizar el tema de las crisis familiares. Se pone de manifiesto que tanto los eventos propios del desarrollo, como los accidentales, dan lugar a la aparición de crisis en la familia. Queda esclarecido, que no necesariamente han de tener implicaciones negativas para la familia. Se hace énfasis en la valoración del evento por la familia y su significación. Se destaca el papel de los recursos familiares como protectores y moduladores de las crisis. Por último se señalan algunos pasos a seguir en la intervención familiarWith this paper we intend to update the topic of the family crises. It is shown that the own events of development as well as the accidental ones bring about the appearance of crises in the family. It is made clear that they not always have negative implications for the family. Emphasis is made on the assessment of the event for the family and its significance. The role played by the family resources as protective and modulators of the crisis is stressed. Finally, some of the steps to be taken in family intervention are mentioned

  14. Effect of Precipitable Water Vapor Amount on Radiative Cooling Performance

    Science.gov (United States)

    Hu, Mingke; Zhao, Bin; Ao, Xianze; Pei, Gang

    2017-05-01

    A radiative cooler based on aluminum-evaporated polyvinyl-fluoride surface was employed to investigate the effect of precipitable water vapor amount on its radiative cooling performance. A mathematic model of steady heat transfer that considers the spectral radiant distribution of the sky, the transparent cover and the collecting surface was established. The results indicate that the amount of precipitable water vapor shows a remarkable and negative effect on radiative cooling performance of the radiative cooler. Both the temperature difference between the cooler and surroundings and the net radiative cooling power decrease as the precipitable water vapor amount increases. The net radiative cooling power drops by about 41.0% as the the precipitable water vapor amount changes from 1.0 cm to 7.0 cm. Besides, the radiative cooler shows better cooling performance in winter than in summer. The net radiative cooling power in summer of Hefei is about 82.2% of that in winter.

  15. Vaporization of comet nuclei - Light curves and life times

    Science.gov (United States)

    Cowan, J. J.; Ahearn, M. F.

    1979-01-01

    The effects of vaporization from the nucleus of a comet are examined and it is shown that a latitude dependence of vaporization can explain the asymmetries in cometary light curves. An attempt is made to explain the observed variation in molecular production rates with heliocentric distance when employing CO2 and clathrate hydrate ice as cometary nuclei substances. The energy balance equation and the vapor pressure equations of water and CO2 are used in calculating the vaporization from a surface. Calculations were carried out from both dry-ice and water-ice nuclei, using a variety of different effective visual albedos, but primarily for a thermal infrared of 0 (emission). Attention is given to cometary lifetimes and light curves and it was determined that the asymmetry in light curves occurs (occasionally) as a 'seasonal' effect due to a variation in the angle between the comet's rotation axis and the sun-comet line.

  16. Vapor Compressor Driven Hybrid Two-Phase Loop Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I project successfully demonstrated the feasibility of the vapor compression hybrid two-phase loop (VCHTPL). The test results showed the high...

  17. Vapor Compressor Driven Hybrid Two-Phase Loop Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will demonstrate a vapor compressor driven hybrid two-phase loop technology. The hybrid two-phase loop...

  18. Experimental Measurements of Diffusivity of Vapors through Porous Substrates

    Science.gov (United States)

    Li, Hongyang; Rincon, Carlos; Bowden, Elizabeth; Zand, Ali; Sikorski, Yuri; Sanders, Matthew; Navaz, Homayun

    2007-05-01

    The release of numerous toxic chemicals, such as hydrocarbons, pesticides, chemical warfare agents, etc.; into soil, subsurface, concrete, brick and asphalt poses a great threat to the biosphere environment. The quantification and extent of spread of these chemicals has primary importance for carrying out the remediation work. There are several well known spread mechanisms which govern the mass transport in porous media. They include various regimes of liquid and vapor transport/diffusion. Modeling the transport of vapors in porous substrates requires the knowledge of the diffusivity of each particular vapor in each substrate. We present a simple, effective and inexpensive experimental method and apparatus for measurement of vapor diffusivity in porous media. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.OSS07.P1.24

  19. Graphene-oxide-coated interferometric optical microfiber ethanol vapor sensor.

    Science.gov (United States)

    Zhang, Jingle; Fu, Haiwei; Ding, Jijun; Zhang, Min; Zhu, Yi

    2017-11-01

    A graphene-oxide-coated interferometric microfiber-sensor-based polarization-maintaining optical fiber is proposed for highly sensitive detecting for ethanol vapor concentration at room temperature in this paper. The strong sensing capability of the sensor to detect the concentration of ethanol vapor is demonstrated, taking advantage of the evanescent field enhancement and gas absorption of a graphene-oxide-coated microfiber. The transmission spectrum of the sensor varies with concentrations of ethanol vapor, and the redshift of the transmission spectrum has been analyzed for the concentration range from 0 to 80 ppm with sensitivity as high as 0.138 nm/ppm. The coated graphene oxide layer induces the evanescent field enhancement and gas selective adsorption, which improves sensitivity and selectivity of the microfiber gas sensor for ethanol vapor detection.

  20. EPA Method 245.2: Mercury (Automated Cold Vapor Technique)

    Science.gov (United States)

    Method 245.2 describes procedures for preparation and analysis of drinking water samples for analysis of mercury using acid digestion and cold vapor atomic absorption. Samples are prepared using an acid digestion technique.

  1. Cesium vapor thermionic converter anomalies arising from negative ion emission

    Science.gov (United States)

    Rasor, Ned S.

    2016-08-01

    Compelling experimental evidence is given that a longstanding limit encountered on cesium vapor thermionic energy converter performance improvement and other anomalies arise from thermionic emission of cesium negative ions. It is shown that the energy that characterizes thermionic emission of cesium negative ions is 1.38 eV and, understandably, is not the electron affinity 0.47 eV determined for the photodetachment threshold of the cesium negative ion. The experimental evidence includes measurements of collector work functions and volt-ampere characteristics in quasi-vacuum cesium vapor thermionic diodes, along with reinterpretation of the classic Taylor-Langmuir S-curve data on electron emission in cesium vapor. The quantitative effects of negative ion emission on performance in the ignited, unignited, and quasi-vacuum modes of cesium vapor thermionic converter operation are estimated.

  2. Continuous flow, explosives vapor generator and sensor chamber

    Science.gov (United States)

    Collins, Greg E.; Giordano, Braden C.; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D.; Tucker, John E.; Malito, Michael; Eversole, Jay D.; Rose-Pehrsson, Susan

    2014-05-01

    A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

  3. Solvent vapor annealing of an insoluble molecular semiconductor

    KAUST Repository

    Amassian, Aram

    2010-01-01

    Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

  4. Investigation of odd-order nonlinear susceptibilities in atomic vapors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yaqi [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049 (China); Shaanxi Key Laboratory of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China); Teaching and Research Section of Maths and Physics, Guangzhou Commanding Academy of Chinese People’s Armed Police Force, Guangzhou, 510440 (China); Wu, Zhenkun; Si, Jinhai; Yan, Lihe; Zhang, Yiqi; Yuan, Chenzhi; Sun, Jia [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049 (China); Shaanxi Key Laboratory of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Yanpeng, E-mail: ypzhang@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049 (China); Shaanxi Key Laboratory of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)

    2013-06-15

    We theoretically deduce the macroscopic symmetry constraints for arbitrary odd-order nonlinear susceptibilities in homogeneous media including atomic vapors for the first time. After theoretically calculating the expressions using a semiclassical method, we demonstrate that the expressions for third- and fifth-order nonlinear susceptibilities for undressed and dressed four- and six-wave mixing (FWM and SWM) in atomic vapors satisfy the macroscopic symmetry constraints. We experimentally demonstrate consistence between the macroscopic symmetry constraints and the semiclassical expressions for atomic vapors by observing polarization control of FWM and SWM processes. The experimental results are in reasonable agreement with our theoretical calculations. -- Highlights: •The macroscopic symmetry constraints are deduced for homogeneous media including atomic vapors. •We demonstrate that odd-order nonlinear susceptibilities satisfy the constraints. •We experimentally demonstrate the deduction in part.

  5. Catalytic combustion of heavy partially-vaporized fuels

    Science.gov (United States)

    Rosfjord, T. J.

    1980-01-01

    An experimental program to demonstrate efficient catalytic combustion of fuel-lean and fuel-rich mixtures of residual fuel and air, and to assess the influence of incomplete fuel vaporization on the performance of a catalytic reactor is being conducted. A 7.5-cm diameter catalytic reactor was designed and will be tested over a matrix of conditions representative of a gas turbine combustor inlet. For each of three test phases, two series of tests with a uniform but poorly vaporized (less than 50 percent) mixture of No. 6 fuel oil and air will be performed. In the first series, the non-vaporized fuel will be contained in a spray of droplets with a Sauter Mean Diameter (SMD) less than 30 microns. In the second series, the non-vaporized fuel will be characterized by a spray SMD approximately equal to 100 microns. The designs of the fuel injection system and the catalytic reactor are described in this paper.

  6. 33 CFR 154.826 - Vapor compressors and blowers.

    Science.gov (United States)

    2010-07-01

    ... be fitted with: (1) A detonation arrester; (2) A flame arrester; or (3) An explosion suppression...) Excessive shaft bearing temperature. (d) If a centrifugal compressor, fan, or lobe blower handles vapor in...

  7. Regulación de la temperatura del vapor sobrecalentado en un generador de vapor BKZ-340-140-29M de 100 MW mediante un control PID 2-GdL y filtraje de la medida

    Directory of Open Access Journals (Sweden)

    Tania García Martínez

    2012-12-01

    Full Text Available En este artículo se presenta una mejora del lazo de regulación de la temperatura del vapor sobrecalentado en un generador de vapor BKZ-340-140-29M de 100 MW. El estudio se realiza en la Central Termoeléctrica Máximo Gómez. La propuesta consiste en un controlador PID con una estructura de dos grados de libertad y filtraje de la medida. El diseño, que incluye un criterio de robustez, tiene como objetivo fundamental la atenuación de las perturbaciones de carga producidas por la variación del flujo de vapor. El ruido de medida se resuelve filtrando la salida con un filtro de segundo orden. La ponderación del punto de consigna se utiliza para mejorar los cambios en la referencia. La propuesta se compara con el desempeño del controlador implementado actualmente en el lazo. Los resultados confirman los beneficios del diseño, garantizando así una mejor eficiencia del lazo.

  8. Transformaciones previsibles de las violencias que padecen las mujeres

    OpenAIRE

    Martín Serrano, Manuel

    2008-01-01

    Manuel Martín Serrano ha investigado desde los inicios de la Democracia en España las violencias estructurales, entre ellas las que afectan a las mujeres. Su conferencia en el Congreso Internacional "Mundos de Mujeres" (Madrid, 2008) está reeditada en este artículo. Realiza un diagnóstico diferente de las modalidades de violencia, sus orígenes, efectos y previsibles transformaciones, basado en análisis sociohistóricos, que difiere en mucho de los tradicionales. Expone el autor que coexisten p...

  9. Degree of Vaporization in Bipolar and Monopolar Resection

    OpenAIRE

    Fagerstrom, Tim; Nyman, Claes R.; Hahn, Robert G.

    2012-01-01

    Purpose: To compare the in vitro degree of vaporization in bipolar and monopolar resection. less thanbrgreater than less thanbrgreater thanMaterials and Methods: Using either a bipolar system or a monopolar system, samples of chicken muscle and lamb kidney were resected in an isolated basin and then desiccated in an incubator. The percentual degree of vaporization for each sample was obtained as a difference between the total fresh weight of the sample and the calculated fresh weights of the ...

  10. CRISM Observations of Water Vapor and Carbon Monoxide

    Science.gov (United States)

    Smith, Michael D.; Wolff, Michael J.; Clancy, R. Todd

    2008-01-01

    Near-infrared spectra returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM, [1]) on-board the Mars Reconnaissance Orbiter (MRO) contain the clear spectral signature of several atmospheric gases including carbon dioxide (CO2), water vapor (H2O), and carbon monoxide (CO). Here we describe the seasonal and spatial mapping of water vapor and carbon dioxide for one full Martian year using CRISM spectra.

  11. Regolith water vapor sources on Mars: A historical bibliography

    Science.gov (United States)

    Clifford, Stephen M.; Huguenin, R. L.

    1988-01-01

    The regolith as a potential source and sink of atmospheric water is examined bibliographically. The controversy surrounding Solis Lacus, a region on Mars first identified by R. Huguenin as a possible regolith source of atmospheric water vapor, is reviewed. The publications listed describe the initial debate over the existence of a regolith source of atmospheric water vapor in Solis Lacus. The debate over Solis Lacus has motivated a rigorous examination of several important data sets, and helped define the limits of their interpretation.

  12. Aluminum coating by fluidized bed chemical vapor deposition on austenitic stainless steels AISI 304 and AISI 316

    Directory of Open Access Journals (Sweden)

    Jose Luddey Marulanda-Arevalo

    2015-01-01

    Full Text Available Los revestimientos de aluminio f ueron depositados sobre aceros inoxidables AISI 304 y AISI 316 en el rango de temperatura de 5 60 a 600 °C por deposición química de vapor en lecho fluidizado(CVD – FBR. Se utilizó un lecho que consistía en 10 % de aluminio en polvo y 90 % de lecho inerte (alúmina, el cual fue fluidizado con Ar y como ga ses activadores se utilizó una mezcla de ácido clorhídrico con hidrógeno (HCl/H 2 . En el recubrimiento si n tratamiento térmico están las siguiente s especies: Al 13 Fe 4 , Fe 2 Al 5 , FeAl 2 y Al 5 FeNi, las cuales están presentes para ambos aceros. Además, el tratamiento térmico provoca la difusa de alu minio hacia el sustrato y la difusa de hierro del sustrato haci a la superficie del recubrimiento, haciendo la trans formación de los compuestos ant eriores a FeAl, Fe 2 Al 5 , FeAl 2 , Al 0.99 Fe 0.99 Ni 0.02 , AlNi y el Fe 2 AlCr. Se realizó la simulación termodinámica con el s oftware Thermo Calc para obt ener información de la posible composición y la cantidad de mat erial depositado, para condiciones seleccionadas. Las muestras recubi ertas y sin recubrir, se expus ieron a 750 ºC en una atmósfera d onde el vapor agua se transporta a las muestras usando un flujo de N 2 de 40 ml/min, más 100 % vapor de agua (H 2 O. Los dos sustratos sin revestir se comportaron de manera diferente, ya que el acero AISI 304 soportó bien el a taque y ganó poco peso (0.49 mg/cm 2 , en comparación con el acero AISI 316 que perdió mucho peso (25.4 mg/cm 2 . Los aceros recubiertos ganaron poco de peso durante las mil horas de exposición (0.26 mg/cm 2 y soportaron muy bien el ataque corrosivo en c omparación con sustratos sin r ecubrimiento.

  13. Dynamic friction characterization in a turbine rotor and metallographic analysis of the friction element; Caracterizacion dinamica del rozamiento en rotor de turbina y analisis metalografico del elemento de rozamiento

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Solis, Jose Antonio; Cristalinas Navarro, Victor Manuel; Mojica Calderon, Cecilio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    As a part of the diagnosis of the root cause of the blades fault of the of the L-1 wheel of a of low pressure rotor of 300 MW, in one of the Power stations of Electrical Generation, a design was made and an experimental rubbing test of friction in the same rotor was performed but in the adjacent wheel of movable blades L-2. The objectives of the experimental rubbing test were to determine the dynamic characteristics of the rubbing to corroborate what was observed in the diagrams of spectra registered by the power station during the operation of the Unit, to determine the maximum bending stress of the used element to provide rubbing to the wheel of blades L-2 and to infer in a qualitative way the magnitude of the necessary friction force to generate the dynamic characteristics of the rubbing and finally to determine the micro-structural changes that underwent the element employed to apply rubbing. [Spanish] Como parte del diagnostico de la causa raiz de la falla de los alabes de la rueda L-1 de un rotor de baja presion de 300 MW, en una de las Centrales de Generacion Electrica, se diseno y efectuo una prueba experimental de rozamiento en el mismo rotor pero en la rueda adyacente de alabes moviles L-2. Los objetivos de la prueba experimental de rozamiento fueron determinar las caracteristicas dinamicas del rozamiento para corroborar lo observado en los diagramas de espectros registrados por la Central durante la operacion de la Unidad, determinar el esfuerzo maximo a la flexion del elemento utilizado para suministrar rozamiento a la rueda de alabes L-2 e inferir de manera cualitativa la magnitud de la fuerza de rozamiento necesaria para generar las caracteristicas dinamicas del razonamiento y por ultimo determinar los cambios microestructurales que experimento el elemento utilizado para aplicar rozamiento.

  14. Dynamic characterization of the friction in turbine rotor and metallographic analysis of the friction element; Caracterizacion dinamica del rozamiento en rotor de turbina y analisis metalografico del elemento de rozamiento

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Solis, Jose Antonio; Cristalinas Navarro, Victor Manuel; Mojica Calderon, Cecilio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2010-07-01

    As a part of the diagnosis of the root cause of the fault of the blades of the L-1 wheel of a of low pressure rotor of 200 MW, in one of the power stations of electrical generation, an experimental test of friction in the same rotor was designed and carried out, but in the adjacent wheel of movable blades L-2. The objectives of the friction experimental test were to determine the dynamic characteristics of the friction, to corroborate what it was observed in the spectra diagrams registered by the power station during the operation of the unit, to determine the maximum bending stress of the used element to provide friction to the wheel of L-2 blades and to infer, in a qualitative way, the magnitude of the force of friction necessary to generate the dynamic characteristics of the friction and finally to determine the micro-structural changes that underwent the used element to apply friction. [Spanish] Como parte del diagnostico de la causa raiz de la falla de los alabes de la rueda L-1 de un rotor de baja presion de 200 MW, en una de las centrales de generacion electrica, se diseno y efectuo una prueba experimental de rozamiento en el mismo rotor, pero en la rueda adyacente de alabes moviles L-2. Los objetivos de la prueba experimental de rozamiento fueron determinar las caracteristicas dinamicas del razonamiento, para corroborar lo observado en los diagramas de espectros registrados por la central durante la operacion de la unidad, determinar el esfuerzo maximo a la flexion del elemento utilizado para suministrar rozamiento a la rueda de alabes L-2 e inferir, de manera cualitativa, la magnitud de la fuerza de rozamiento necesaria para generar las caracteristicas dinamicas del rozamiento y por ultimo determinar los cambios microestructurales que experimento el elemento utilizado para aplicar rozamiento.

  15. An evaluation of vapor extraction of vadose zone contamination

    Energy Technology Data Exchange (ETDEWEB)

    Crotwell, A.T.; Waehner, M.J.; MacInnis, J.M.; Travis, C.C. (Oak Ridge National Lab., TN (United States)); Lyon, B.F. (Oak Ridge Associated Universities, Inc., TN (United States))

    1992-05-01

    An in-depth analysis of vapor extraction for remediation of soils contaminated with volatile organic compounds (VOCS) was conducted at 13 sites. The effectiveness of vapor extraction systems (VES) was evaluated on the basis of soil concentrations of VOCs and soil-gas concentrations of VOC's. The range of effectiveness was found to be 64%--99% effective in removing organic contaminants from soil. At nine of the 13 sites studied in this report, vapor extraction was found to be effective in reducing VOC cooncentrations by at least 90%. At the remaining four sites studied, vapor extraction was found to reduce VOC concentrations by less than 90%. Vapor extraction is ongoing at two of these sites. At a third, the ineffectiveness of the vapor extraction is attributed to the presence of hot spots'' of contamination. At the fourth site, where performance was found to be relatively poor, the presence of geological tar deposits at the site is thought to be a major factor in the ineffectiveness.

  16. Logarithmic radiative effect of water vapor and spectral kernels

    Science.gov (United States)

    Bani Shahabadi, Maziar; Huang, Yi

    2014-05-01

    Radiative kernels have become a useful tool in climate analysis. A set of spectral kernels is calculated using a moderate resolution atmospheric transmission code MODTRAN and implemented in diagnosing spectrally decomposed global outgoing longwave radiation (OLR) changes. It is found that the effect of water vapor on the OLR is in proportion to the logarithm of its concentration. Spectral analysis discloses that this logarithmic dependency mainly results from water vapor absorption bands (0-560 cm-1 and 1250-1850 cm-1), while in the window region (800-1250 cm-1), the effect scales more linearly to its concentration. The logarithmic and linear effects in the respective spectral regions are validated by the calculations of a benchmark line-by-line radiative transfer model LBLRTM. The analysis based on LBLRTM-calculated second-order kernels shows that the nonlinear (logarithmic) effect results from the damping of the OLR sensitivity to layer-wise water vapor perturbation by both intra- and inter-layer effects. Given that different scaling approaches suit different spectral regions, it is advisable to apply the kernels in a hybrid manner in diagnosing the water vapor radiative effect. Applying logarithmic scaling in the water vapor absorption bands where absorption is strong and linear scaling in the window region where absorption is weak can generally constrain the error to within 10% of the overall OLR change for up to eightfold water vapor perturbations.

  17. Decreased respiratory symptoms in cannabis users who vaporize

    Directory of Open Access Journals (Sweden)

    Barnwell Sara

    2007-04-01

    Full Text Available Abstract Cannabis smoking can create respiratory problems. Vaporizers heat cannabis to release active cannabinoids, but remain cool enough to avoid the smoke and toxins associated with combustion. Vaporized cannabis should create fewer respiratory symptoms than smoked cannabis. We examined self-reported respiratory symptoms in participants who ranged in cigarette and cannabis use. Data from a large Internet sample revealed that the use of a vaporizer predicted fewer respiratory symptoms even when age, sex, cigarette smoking, and amount of cannabis used were taken into account. Age, sex, cigarettes, and amount of cannabis also had significant effects. The number of cigarettes smoked and amount of cannabis used interacted to create worse respiratory problems. A significant interaction revealed that the impact of a vaporizer was larger as the amount of cannabis used increased. These data suggest that the safety of cannabis can increase with the use of a vaporizer. Regular users of joints, blunts, pipes, and water pipes might decrease respiratory symptoms by switching to a vaporizer

  18. Bronchoscopic thermal vapor ablation in a canine model of emphysema

    Directory of Open Access Journals (Sweden)

    Tuck SA

    2012-01-01

    Full Text Available Stephanie A Tuck1, Vanessa Lopes-Berkas2, Sheree Beam3, Joseph C Anderson11Uptake Medical Corp, Seattle, WA, 2American Preclinical Services, Coon Rapids, MN, 3Preclinical Pathology Consulting Services, Ham Lake, MN, USAAbstract: Clinical studies indicate the potential of bronchoscopic thermal vapor ablation to result in clinically relevant improvements in severe chronic obstructive pulmonary disease patients with upper lobe-predominant emphysema. However, the mechanisms by which vapor ablation results in lung volume reduction are not fully known. This study determined the 3-month safety and efficacy of vapor ablation in a canine model of emphysema and described the histopathological changes in the lung. The cranial lobes of papain-exposed dogs were treated with a vapor dose of ten calories per gram of lung tissue (n = 8 or were sham treated (n = 3. Safety was monitored peri- and postoperatively for 3 months. Animals were then sacrificed, estimates of lung volume reduction performed, and the lungs processed for histology. Vapor ablation was associated with an average of 20% volume reduction of the treated lobes and an absence of serious adverse events. The amount of lobar volume reduction was correlated with the amount of fibrosis and atelectasis in the treated lobe. Bronchoscopic thermal vapor ablation at a dose of 10 cal/g results in lobar volume reduction associated with remodeling of the targeted tissue characterized by mature collagen formation in the absence of major adverse events.Keywords: animal models, chronic obstructive pulmonary disease, bronchoscopy, lung volume reduction

  19. Bronchoscopic thermal vapor ablation in a canine model of emphysema.

    Science.gov (United States)

    Tuck, Stephanie A; Lopes-Berkas, Vanessa; Beam, Sheree; Anderson, Joseph C

    2012-01-01

    Clinical studies indicate the potential of bronchoscopic thermal vapor ablation to result in clinically relevant improvements in severe chronic obstructive pulmonary disease patients with upper lobe-predominant emphysema. However, the mechanisms by which vapor ablation results in lung volume reduction are not fully known. This study determined the 3-month safety and efficacy of vapor ablation in a canine model of emphysema and described the histopathological changes in the lung. The cranial lobes of papain-exposed dogs were treated with a vapor dose of ten calories per gram of lung tissue (n = 8) or were sham treated (n = 3). Safety was monitored peri- and postoperatively for 3 months. Animals were then sacrificed, estimates of lung volume reduction performed, and the lungs processed for histology. Vapor ablation was associated with an average of 20% volume reduction of the treated lobes and an absence of serious adverse events. The amount of lobar volume reduction was correlated with the amount of fibrosis and atelectasis in the treated lobe. Bronchoscopic thermal vapor ablation at a dose of 10 cal/g results in lobar volume reduction associated with remodeling of the targeted tissue characterized by mature collagen formation in the absence of major adverse events.

  20. Urban emissions of water vapor in winter

    Science.gov (United States)

    Salmon, Olivia E.; Shepson, Paul B.; Ren, Xinrong; Marquardt Collow, Allison B.; Miller, Mark A.; Carlton, Annmarie G.; Cambaliza, Maria O. L.; Heimburger, Alexie; Morgan, Kristan L.; Fuentes, Jose D.; Stirm, Brian H.; Grundman, Robert; Dickerson, Russell R.

    2017-09-01

    Elevated water vapor (H2Ov) mole fractions were occasionally observed downwind of Indianapolis, IN, and the Washington, D.C.-Baltimore, MD, area during airborne mass balance experiments conducted during winter months between 2012 and 2015. On days when an urban H2Ov excess signal was observed, H2Ov emission estimates range between 1.6 × 104 and 1.7 × 105 kg s-1 and account for up to 8.4% of the total (background + urban excess) advected flow of atmospheric boundary layer H2Ov from the urban study sites. Estimates of H2Ov emissions from combustion sources and electricity generation facility cooling towers are 1-2 orders of magnitude smaller than the urban H2Ov emission rates estimated from observations. Instances of urban H2Ov enhancement could be a result of differences in snowmelt and evaporation rates within the urban area, due in part to larger wintertime anthropogenic heat flux and land cover differences, relative to surrounding rural areas. More study is needed to understand why the urban H2Ov excess signal is observed on some days, and not others. Radiative transfer modeling indicates that the observed urban enhancements in H2Ov and other greenhouse gas mole fractions contribute only 0.1°C d-1 to the urban heat island at the surface. This integrated warming through the boundary layer is offset by longwave cooling by H2Ov at the top of the boundary layer. While the radiative impacts of urban H2Ov emissions do not meaningfully influence urban heat island intensity, urban H2Ov emissions may have the potential to alter downwind aerosol and cloud properties.

  1. Water vapor sorption properties of cellulose nanocrystals and nanofibers using dynamic vapor sorption apparatus.

    Science.gov (United States)

    Guo, Xin; Wu, Yiqiang; Xie, Xinfeng

    2017-10-27

    Hygroscopic behavior is an inherent characteristic of nanocellulose which strongly affects its applications. In this study, the water vapor sorption behavior of four nanocellulose samples, such as cellulose nanocrystals and nanofibers with cellulose I and II structures (cellulose nanocrystals (CNC) I, CNC II, cellulose nanofibers (CNF) I, and CNF II) were studied by dynamic vapor sorption. The highly reproducible data including the running time, real-time sample mass, target relative humidity (RH), actual RH, and isotherm temperature were recorded during the sorption process. In analyzing these data, significant differences in the total running time, equilibrium moisture content, sorption hysteresis and sorption kinetics between these four nanocellulose samples were confirmed. It was important to note that CNC I, CNC II, CNF I, and CNF II had equilibrium moisture contents of 21.4, 28.6, 33.2, and 38.9%, respectively, at a RH of 95%. Then, the sorption kinetics behavior was accurately described by using the parallel exponential kinetics (PEK) model. Furthermore, the Kelvin-Voigt model was introduced to interpret the PEK behavior and calculate the modulus of these four nanocellulose samples.

  2. Preservar las empresas de familia

    Directory of Open Access Journals (Sweden)

    José Vargas Caicedo

    2005-12-01

    Full Text Available El ciclo de vida de las empresas de familia es usualmente corto por muchas razones. Entre las más frecuentes podemos considerar la marcada ignorancia acerca de los mecanismos adecuados para la solución de los conflictos, y este es el más común de los temas. La lucha por el poder, por la propiedad y la competencia en el cuidado de las realizaciones personales genera fricciones frecuentes entre los miembros de una familia. Las actitudes y las respuestas de tipo emocional que por lo general se dan en la solución de problemas en esta clase de organizaciones muchas veces deriva en la polarización y ruptura definitiva de las relaciones.

  3. MEDICIÓN DEL EQUILIBRIO LIQUIDO-VAPOR DEL SISTEMA METANOL-ACETATO DE METILO A 580 mmHg

    Directory of Open Access Journals (Sweden)

    Carlos Ariel Cardona

    2008-03-01

    Full Text Available En este trabajo se midió experimentalmente el equilibrio líquido-vapor para el sistema binario metanol–acetato de Metilo a 580 mmHg. Las mediciones experimentales fueron realizadas utilizando un equipo con recirculación tipo Cottrell. Los datos obtenidos fueron comparados con los resultados adquiridos de la simulación del equilibrio líquido-vapor del sistema bajo estudio. En la simulación se empleó el modelo de actividad NRTL para representar la no idealidad de la fase líquida (con parámetros encontrados en la literatura, y la ecuación de estado de Hayden O´Connel para la no idealidad de la fase vapor. De igual manera, se correlacionaron los datos para encontrar nuevos parámetros del modelo de actividad en NRTL. Además, a partir de datos experimentales medidos a 760 mmHg encontrados en la literatura para el sistema estudiado, se verificó la Ley de Vresky, la cual permite, sin necesidad de cálculos rigurosos, predecir la dirección de desplazamiento de un azeótropo binario cunado se varía la presión del sistema.

  4. Tank 241-TY-104 headspace gas and vapor characterization results for samples collected in April 1995

    Energy Technology Data Exchange (ETDEWEB)

    Huckaby, J.L. [Pacific Northwest Lab., Richland, WA (United States); Bratzel, D.R. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-09-01

    Significant changes have been made to all of the original vapor characterization reports. This report documents specific headspace gas and vapor characterization results for all vapor sampling events to date. In addition, changes have been made to the original vapor reports to qualify the data based on quality assurance issues associated with the performing laboratories.

  5. In-Situ Water Vapor Probe for a Robot Arm-Mounted, Compact Water Vapor Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to test a prototype water vapor sampling end-effector in the laboratory and in the field thatwill eventually be integrated with a small, infrared...

  6. Ambiente psicologico en las organizaciones

    Directory of Open Access Journals (Sweden)

    Damarcy Cortés Baracaldo

    2002-01-01

    Full Text Available El talento humano en las organizaciones se ha convertido en las ultimas decadas en un recurso que se administra de acuerdo al estilo de liderazgo del jefe, lo que implica una marcada relación hacia la tarea, hacia las relaciones con el personal o una combinación de estas dos, que desencadenan en un ambiente psicológico exclusive en cada organización.

  7. Las identidades del dinero

    Directory of Open Access Journals (Sweden)

    CELSO SÁNCHEZ CAPDEQUÍ

    2005-01-01

    Full Text Available A lo largo del trabajo se ha pretendido desvelar los momentos sociales y simbólicos que constituyen la extensa biografía del dinero. En ausencia de una racionalidad económica diferenciada, el dinero nace, de forma no deliberada, en el templo bajo la atmósfera sacrificial, comparece en la modernidad como medio técnico que representa la esperanza del individuo propietario en la bonhomía del mercado como elemento pacificador de las costumbres sociales, y arriba a nuestra posmodernidad como fin en sí mismo que, convertido en bit desmaterializado, aspira a no dejar de circular por el nuevo espacio virtual.

  8. Las Gramináceas

    Directory of Open Access Journals (Sweden)

    Robledo Emilio

    1939-08-01

    Full Text Available Las gramináceas son plantas conocidas desde la antigüedad más remota. Tan importantes son las gramináceas desde el punto de vista bromatológico, que los hombres pueden ser clasificados en comedores de trigo, de arroz, de maíz, de mijo, de sorgo, de tocusso, de tef, etc. El área de distribución de las gramíneas es inmensa: se las encuentra desde las orillas del mar y en las aguas dulces, hasta las nieves perpetuas; sólo en las aguas saladas desconocidas. En punto de tamaño, las hay desde unos centímetros hasta nuestra guadua gigantesca, de treinta y más metros de altura. Dicha distribución se halla en relación con el clima, pero también es influida por los hábitos de los pueblos, por la civilización, por el comercio o por otras circunstancias.

  9. La universidad en las empresas

    Directory of Open Access Journals (Sweden)

    Irene Pineda Ferrnan

    2002-12-01

    Full Text Available Los cambios operados en la sociedad, las relaciones entre las empresas y los conocimientos, no siempre se traducen en un enriquecimiento de vínculos entre organizaciones productivas y universidades. En este artículo se aborda la educación en un sentido amplio, las diferentes formas de educación que se forja al interior de las empresas, así como el contexto cultural de la empresa y su vinculación con la educación.

  10. Las TIC como fuente de ventaja competitiva en las PYMES

    Directory of Open Access Journals (Sweden)

    Álvaro Fernando Moncada Niño

    2013-07-01

    Full Text Available Desde su aparición, las Tecnologías de la Información y las Comunicaciones (TIC se han convertido en un recurso fundamental de las empresas para competir en la mayoría de las industrias, generalizando el planteamiento de que son fuente de ventaja competitiva. Pero realmente, ¿cuándo las TIC son fuente potencial de ventaja competitiva para las pymes? ¿Bajo qué condiciones se logra que contribuyan a generar valor y mejorar su posición competitiva? ¿Qué características deben cumplir para alcanzar y sustentar la Ventaja Competitiva? Este documento basado en la Teoría de los Recursos y Capacidades (TRC responde estas preguntas y presenta al análisis de recurso Valioso, Raro, Inimitable y Organización (VRIO como herramienta para la determinación del potencial y valor que las TIC pueden alcanzar en las pymes y cómo pueden contribuir a que la empresa alcance ventajas competitivas sostenibles, en complemento de sus recursos y capacidades organizacionales.

  11. Las TIC como fuente de ventaja competitiva en las PYMES

    Directory of Open Access Journals (Sweden)

    Álvaro Fernando Moncada Niño

    2013-06-01

    Full Text Available Desde su aparición, las Tecnologías de la Información y las Comunicaciones (TIC se han convertido en un recurso fundamental de las empresas para competir en la mayoría de las industrias, generalizando el planteamiento de que son fuente de ventaja competitiva. Pero realmente, ¿cuándo las TIC son fuente potencial de ventaja competitiva para las pymes? ¿Bajo qué condiciones se logra que contribuyan a generar valor y mejorar su posición competitiva? ¿Qué características deben cumplir para alcanzar y sustentar la Ventaja Competitiva? Este documento basado en la Teoría de los Recursos y Capacidades (TRC responde estas preguntas y presenta al análisis de recurso Valioso, Raro, Inimitable y Organización (VRIO como herramienta para la determinación del potencial y valor que las TIC pueden alcanzar en las pymes y cómo pueden contribuir a que la empresa alcance ventajas competitivas sostenibles, en complemento de sus recursos y capacidades organizacionales.

  12. Development and implementation of an interface control-process and of additional models in the simulator of combined cycle units; Desarrollo e implantacion de una interfaz control-proceso y de modelos adicionales en el simulador de unidades de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Martinez R, Rogelio E; Ramirez G, Miguel; Melgar G, Jose L; Codero C, Juan C; Romero J, Guillermo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    In this article are described the design and implementation of an interface control-process and the formulation of the process models for the simulation of the vibration amplitudes of the steam and gas turbines and of the monitoring system of gas discharges, which comprise a simulator of total reach of combined cycle units. These three systems had to be developed and implemented in the simulator of combined cycle units, that the Instituto de Investigaciones Electricas (IIE) developed for the Comision Federal de Electricidad (CFE), with the purpose of solving different problematic caused by the use of a platform of commercial software for the construction of simulators. The problematic presented by the platform of software is briefly described, as well as the solutions contributed with respect to the interconnection of signals control-process, and to the lack of models of the mechanical part of the steam and gas turbines, and of the monitoring system of polluting emissions. [Spanish] En este articulo se describen el diseno e implantacion de una interfaz control-proceso y la formulacion de los modelos de proceso para la simulacion de las amplitudes de vibracion de las turbinas de gas y de vapor y del sistema de monitoreo de emisiones de gases, los cuales forman parte de un simulador de alcance total de unidades de ciclo combinado. Estos tres sistemas tuvieron que ser desarrollados e implementados en el simulador de unidades de ciclo combinado, que el Instituto de Investigaciones electricas (IIE) desarrollo para la Comision Federal de Electricidad (CFE), con el fin de resolver diferentes problematicas ocasionadas por la utilizacion de una plataforma de software comercial para la construccion de simuladores. Se describen brevemente las problematicas presentadas por la plataforma de software, asi como las soluciones aportadas en lo relativo a la interconexion de senales control-proceso, y a la falta de modelos de la parte mecanica de las turbinas de gas y de vapor, y

  13. Mechanical properties of chemical vapor deposited diamond

    Science.gov (United States)

    Kant, Avinash

    The hardness, elastic modulus, subcritical crack growth and fracture toughness of chemical vapor deposited (CVD) polycrystalline diamond films have been investigated on thick (˜100 to 300 mum) free-standing films with regard to the composition, microstructure, failure mechanisms and measurement techniques. The rationale for this study was the uncertainty in measuring these properties in previous research and the variability in the composition and microstructure of the material, which may affect these properties. Two predominant micro-hardness measurement techniques, namely Vickers and Knoop indentation, were employed. Existing Young's modulus measurement techniques such as dynamic resonance and nano-indentation were reviewed for modulus measurement on these films. The validity of indentation fracture toughness measurement for CVD diamond films using micro-hardness indentation has been established based on comparison with the conventional method of tensile testing of pre-notched compact-tension samples. The fracture toughness, Ksbc, of diamond was measured using indentation methods and for the first time by the tensile testing of pre-notched fracture-mechanics type compact-tension samples. Measured Ksbc values were found to be between 5 and 7 MPa-msp{1/2} by either method. Studies on subcritical crack growth (i.e., at stress intensities less than Ksbc) indicated that CVD diamond is essentially immune to stress-corrosion cracking under sustained loads in room air, water and acid environments. Extensive studies of the microstructure and mechanisms of failure were conducted. A commonly known toughening mechanism for ceramics by weakening the grain boundary in order to promote intergranular failure and grain bridging, has been implemented to improve the toughness of CVD diamond films. Several films with nominally the same thickness but small differences in their non-diamond content were studied and a significant variation in the toughness measurements was observed

  14. Vapor pressure and intramolecular hydrogen bonding in fluorotelomer alcohols.

    Science.gov (United States)

    Krusic, Paul J; Marchione, Alexander A; Davidson, Fredric; Kaiser, Mary A; Kao, Chien-Ping C; Richardson, Raymond E; Botelho, Miguel; Waterland, Robert L; Buck, Robert C

    2005-07-21

    Vapor pressure and aqueous solubility are important parameters used to estimate the potential for transport of chemical substances in the atmosphere. For fluorotelomer alcohols (FTOHs), currently under scrutiny by environmental scientists as potential precursors of persistent perfluorocarboxylates (PFCAs), vapor pressure is the more significant property since these compounds are only very sparingly soluble in water. We have measured the vapor pressures of a homologous series of fluorotelomer alcohols, F(CF2CF2)nCH2CH2OH (n = 2-5), in the temperature range 21-250 degrees C by three independent methods: (a) a method suitable for very low vapor pressures at ambient temperatures (gas-saturation method), (b) an improved boiling point method at controlled pressures (Scott method), and (c) a novel method, requiring milligram quantities of substance, based on gas-phase NMR, a technique largely unfamiliar to chemists and holding promise for studies of relevance to environmental chemistry. The concordant values obtained indicate that recently published vapor pressure data overestimate the vapor pressure at ambient temperature, and therefore the volatility, of this series of fluorinated compounds. It was suggested that substantial intramolecular -O-H...F- hydrogen bonding between the hydroxylic proton and the two fluorines next to the ethanol moiety was responsible for their putative high volatility. Therefore, we have used gas-phase NMR, gas-phase FTIR, 2D NMR heteronuclear Overhauser effect measurements, and high-level ab initio computations to investigate the intramolecular hydrogen bonding in fluorotelomer alcohols. Our studies unequivocally show that hydrogen bonding of this type is not significant and cannot contribute to and cause unusual volatility. The substantially lower vapor pressure at ambient temperatures than previously reported resulting from our work is important in developing a valid understanding of the environmental transport behavior of this class of

  15. Las cocinas del infierno. La visualidad de las mujeres en las calderas de Pedro Botero

    OpenAIRE

    Zuriaga Senent, Vicente Francesc

    2013-01-01

    Casi todas las religiones nos hablan del infierno como lugar en el que las almas son torturadas eternamente. El judaísmo lo llama Gehena, la mitología clásica Tártaro y Hades, las religiones paganas Inframundo, y la tradición cristiana castellana Las calderas de Pedro Botero. Los profetas del Antiguo Testamento narran con claridad los tormentos del infierno y Dante en La Divina Comedia nos lo relata con una visión particular. La literatura y el arte nos ofrecen abundancia de imáge...

  16. Analysis and solution of algebraic-differential equations of the steam generation processes; Analisis y resolucion de ecuaciones algebraico-diferenciales de los procesos de generacion de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Herrera, Juan Anibal

    1996-10-01

    steady and dynamic state in orden to: a) Observe the behavior of the variables during the coupling of two or more equipment. b) Observe the characteristics what present the numerical integration method to solve the equipment`s network and analyze the obtained numerical results. In this work the individual mathematical models were analyzed and adapted to operate the equipment with different operating conditions, changes in their geometry and different connections with others equipment. Later an equipment`s network was built to represent the cycle boiler-superheater and a numerical method was chosen to solve the equipment`s network in steady and dynamic state. [Espanol] Este trabajo presenta la construccion, analisis y solucion de una red de equipos en regimen estable y dinamico, a partir de: a) Los modelos matematicos de equipos individuales y de sus especificaciones geometricas. b) Las interconexiones topologicas entre los equipos. c) La seleccion de un metodo numerico para resolver simultaneamente los modelos matematicos. Los modelos matematicos seleccionados representan el ciclo caldera-sobrecalentador. Estos modelos fueron tomados del simulador modular MICROTERM-300, el cual contiene los modelos simplificados de los procesos (agua de alimentacion, caldera, turbinas, etc.) de la planta termoelectrica Francisco Perez Rios de Tula Hidalgo, Mexico. Este trabajo fue desarrollado conforme a las siguientes etapas: 1.- Se selecciono un metodo de integracion numerico para resolver simultaneamente las ecuaciones algebraicas y diferenciales de los equipos que conforman el ciclo caldera-sobrecalentador. 2.- Se adaptaron los modelos matematicos en su forma individual para permitir que los equipos puedan ser dimensionables (que permitan cambios en sus geometrias), flexibles (que puedan operar a diferentes condiciones de operacion) y configurables (que permitan diferentes formas de conexion). Ademas, que tengan una representacion de las ecuaciones que permitan analizarlas y una

  17. CÁLCULO DE LOS ÍNDICES DE CONSUMO DE VAPOR EN LA PLANTA DE LLENADO, LIOFILIZACIÓN Y ENVASE Y OTROS SERVICIOS DEL CENTRO NACIONAL DE BIOPREPARADOS

    Directory of Open Access Journals (Sweden)

    Marta Domingo Montané

    2011-02-01

    Full Text Available El progresivo encarecimiento de los productos y servicios energéticos se ha convertido en una preocupaciónprioritaria para toda industria, es por ello que en esta política nacional de ahorro y conservaciónde portadores energéticos se realiza este trabajo en la Planta de Llenado, Liofilización y Envasey en las áreas de Lavandería y Cocina- Comedor, pertenecientes al Centro Nacional deBiopreparados, con el objetivo de determinar los índices de consumo de vapor en los procesosproductivos. Se realizaron varias corridas con el fin de obtener los consumos de vapor directamentede la práctica o de cálculos, a partir de balances de energía y correlaciones de transferencia de calor.Se calcula también el consumo de vapor dado por las pérdidas al medio ambiente en las tuberías quelo transportan a los puntos de consumo. Se obtuvieron los índices de consumo en cada área de vapor,de combustible y económicos correspondientes. Se recomienda al Centro utilizar los índices deconsumo calculados para la comprobación de la eficiencia energética de las áreas estudiadas.  The progressive rise in the price of the products and energy services have become a high-priorityconcern for all industry, it is for it that in this national politics of saving and energy portersconservation is carried out this work, in the Plant of having Filled, Liofilization and packing;and in the areas of Laundry and Kitchen - dining room, belonging to the Centro Nacional deBiopreparados with the objective of determining the indexes of consumption of vapor in theproductive processes. They were carried out several experiments, with the purpose of obtainingthe consumptions of vapor directly of the practice or of calculations, starting from energy balancesand correlations of heat transfer . The consumption of vapor given by the losses to theenvironment in the pipes, that transports it to the consumption points is also calculated. Theconsumption indexes were obtained in each

  18. La convergencia de las telecomunicaciones

    OpenAIRE

    Galarza, D.

    2000-01-01

    Presenta la evolución de la electrónica y como esta ha influenciado en el desarrollo de las telecomunicaciones, en la creación de redes fijas y móviles. Además visualiza el futuro convergente de las telecomunicaciones.

  19. Las aventuras con el autoscopio

    Directory of Open Access Journals (Sweden)

    Víctor Florencio Ramírez Hernández

    2006-01-01

    Full Text Available El trabajo se inspira en el famoso personaje Harry Potter para hacer un análisis entre la filosofía y las neurociencias, específicamente sobre las condiciones funcionales que hacen posible filosofar.

  20. Seguridad de las aplicaciones web

    OpenAIRE

    Luján Mora, Sergio

    2016-01-01

    Conferencia "Seguridad de las aplicaciones web" impartida en las III Jornadas Informáticas - UTE 2016 en la Facultad de Ciencias de la Ingeniería e Industrias de la Universidad Tecnológica Equinoccial (Quito, Ecuador) el 5 de julio de 2016.

  1. Applying the Water Vapor Radiometer to Verify the Precipitable Water Vapor Measured by GPS

    Directory of Open Access Journals (Sweden)

    Ta-Kang Yeh

    2014-01-01

    Full Text Available Taiwan is located at the land-sea interface in a subtropical region. Because the climate is warm and moist year round, there is a large and highly variable amount of water vapor in the atmosphere. In this study, we calculated the Zenith Wet Delay (ZWD of the troposphere using the ground-based Global Positioning System (GPS. The ZWD measured by two Water Vapor Radiometers (WVRs was then used to verify the ZWD that had been calculated using GPS. We also analyzed the correlation between the ZWD and the precipitation data of these two types of station. Moreover, we used the observational data from 14 GPS and rainfall stations to evaluate three cases. The offset between the GPS-ZWD and the WVR-ZWD ranged from 1.31 to 2.57 cm. The correlation coefficient ranged from 0.89 to 0.93. The results calculated from GPS and those measured using the WVR were very similar. Moreover, when there was no rain, light rain, moderate rain, or heavy rain, the flatland station ZWD was 0.31, 0.36, 0.38, or 0.40 m, respectively. The mountain station ZWD exhibited the same trend. Therefore, these results have demonstrated that the potential and strength of precipitation in a region can be estimated according to its ZWD values. Now that the precision of GPS-ZWD has been confirmed, this method can eventually be expanded to the more than 400 GPS stations in Taiwan and its surrounding islands. The near real-time ZWD data with improved spatial and temporal resolution can be provided to the city and countryside weather-forecasting system that is currently under development. Such an exchange would fundamentally improve the resources used to generate weather forecasts.

  2. Revestimientos corrosibles de las obras

    Directory of Open Access Journals (Sweden)

    Jiménez Montoya, P.

    1958-02-01

    Full Text Available Not availableEstudio y descripción de los distintos tipos de revestimiento que requieren las obras industriales para protegerlas contra las acciones químicas desarrolladas por las substancias puestas en contacto con ellas. El amplio estado evolutivo actual de los procedimientos industriales exige, como es natural, que las construcciones modernas se proyecten con un conocimiento claro, no ya de su estabilidad estructural, sino de la de sus propios materiales, que, por fenómenos corrosivos, pueden causar la ruina de la construcción. En este trabajo se dan los procedimientos de revestir, las características más importantes de estas protecciones y materiales empleados y, finalmente, su comportamiento en contacto con los agentes agresivos normalmente manipulados en la industria.

  3. Las fortificaciones monfortinas

    Directory of Open Access Journals (Sweden)

    Iglesias Almeida, Ernesto

    2001-12-01

    Full Text Available The Monforte de Lemos fortification constitutes the best united defensive of the XIV-XV century to exist be in Galicia. Still conserve the principal door of accès besides the homage tower of his castle. All to be it preserve and restore because it is the essence and origin of the own name of the today city. It is accompany of a short glyptographic, heraldry and the old count palace study.

    Las fortificaciones de Monforte de Lemos constituyen el mejor conjunto defensivo de los siglos XIV-XV existentes en Galicia. Todavía se conservan sus principales puertas de acceso además de la torre del homenaje de su castillo. Todo ello digno de ser conservado y restaurado por ser la esencia y origen del propio nombre de la hoy ciudad. Se acompaña de un breve estudio gliptográfico, heráldico y del antiguo palacio condal.

  4. ¿GENERAN VALOR LAS FUSIONES A LAS EMPRESAS COLOMBIANAS?

    Directory of Open Access Journals (Sweden)

    Gloria Martínez

    2003-01-01

    Full Text Available El presente artículo pretende demostrar si las fusiones generan o no valor a las empresas colombianas. En la primera parte se presentan cifras que muestran cómo esta estrategia empresarial ha tomado fuerza en nuestro país en los últimos años. Para comprender de manera más sencilla se presentan las herramientas utilizadas en el desarrollo del estudio, las cuales constituyen el marco teórico de la investigación; posteriormente se explica con detalle la metodología utilizada y finalmente se presentan las conclusiones obtenidas para los años 1997-1999, que son una buena aproximación para determinar cuáles son las consecuencias que este fenómeno trae para las empresas colombianas en cuanto a generación de valor, ya que el estudio pretende aislar los factores socioeconómicos que podrían limitar el alcance del estudio a un período determinado.

  5. Vaporization and combustion of fuel droplets at supercritical conditions

    Science.gov (United States)

    Yang, Vigor

    1991-01-01

    Vaporization and combustion liquid-fuel droplets in both sub- and super-critical environments have been examined. The formulation is based on the complete conservation equations for both gas and liquid phases, and accommodates finite-rate chemical kinetics and a full treatment of liquid-vapor phase equilibrium at the droplet surface. The governing equations and the associated interface boundary conditions are solved numerically using a fully coupled, implicit scheme with the dual time-stepping integration technique. The model is capable of treating the entire droplet history, including the transition from the subcritical to the supercritical state. As a specific example, the combustion of n-pentane fuel droplets in air is studied for pressures of 5-140 atm. In addition, the dynamic responses of droplet vaporization and combustion to ambient-pressure oscillations are investigated. Results indicate that the droplet gasification and burning mechanisms depend greatly on the ambient pressure. In particular, a rapid enlargement of the vaporization and combustion responses occurs when the droplet surface reaches its critical point, mainly due to the strong variations of latent heat of vaporization and thermophysical properties at the critical state.

  6. Vapor etching of nuclear tracks in dielectric materials

    Science.gov (United States)

    Musket, Ronald G.; Porter, John D.; Yoshiyama, James M.; Contolini, Robert J.

    2000-01-01

    A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.

  7. A new generalized correlation for accurate vapor pressure

    Directory of Open Access Journals (Sweden)

    Luis Fernando Cardona Palacio

    2016-08-01

    Full Text Available In this work, a new generalized correlation for pure substances is proposed for the estimation of vapor pressure, applicable in wide temperature range. Was used equilibrium liquid-vapor data with 28 refrigerants and minimizing the sum of the squares of the relative deviation in liquid-vapour pressure were determined the parameters and constants characteristics of the new equation and generalized for any pure substance using the acentric factor. Vapor pressure predictions were made for 45 pure substances who they didn´t not participate in the minimization, generated percent relative average deviation of 1.6073%. The results were compared with others equations for calculating the vapor pressure and  the  comparison  indicates  that  the  proposed  method provide  more  accurate  results  than  other  methods  used  in  this  work. Finally, the calculations of enthalpies of vaporization were done with deviations of 0.880% and the Waring criterion was applied to check the constants presed in this paper

  8. Degree of vaporization in bipolar and monopolar resection.

    Science.gov (United States)

    Fagerström, Tim; Nyman, Claes R; Hahn, Robert G

    2012-11-01

    To compare the in vitro degree of vaporization in bipolar and monopolar resection. Using either a bipolar system or a monopolar system, samples of chicken muscle and lamb kidney were resected in an isolated basin and then desiccated in an incubator. The percentual degree of vaporization for each sample was obtained as a difference between the total fresh weight of the sample and the calculated fresh weights of the resected tissue and remains. Reference samples showed that the water content was 73% in muscle and 77% in kidney. More muscle (mean 52%) than kidney (32%; Pvaporized. The fraction of vaporized tissue was significantly higher in the bipolar technique. In muscle, the differences between monopolar and bipolar were 17% (Pvaporization when using the bipolar resection showed that the choice of loop (Pvaporization. This study indicated that vaporization removes 50% more tissue than the weight of the resected tissue during conventional tissue resection. Bipolar standard loop resection resulted in a significantly higher degree of vaporization in both muscle and kidney than did monopolar technique. Bipolar resection worked satisfactorily in Ringer's acetate.

  9. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  10. Stable isotope ratios of rain and vapor in 1995 hurricanes

    Science.gov (United States)

    Lawrence, James Robert; Gedzelman, Stanley David; Zhang, Xiaoping; Arnold, Robert

    1998-05-01

    Isotope ratios of rain and vapor samples collected at the surface from four tropical cyclones during the active 1995 Atlantic hurricane season were determined. A two-dimensional bulk microphysics isotope model was applied to steady symmetric tropical cyclones to explain the observed low mean values and inward decrease of isotope ratios of the rain and vapor. The low mean value is caused by the tropical cyclone's relatively large size, longevity, and deep clouds. The inward decrease is due to diffusive isotope exchange between falling rain and converging vapor in the atmospheric boundary layer. Dean, a minimal tropical storm, produced relatively high isotope ratios because of its small size and youth. Rains from the extreme outer edge of Felix, a category 3 hurricane, exhibited high isotope ratios similar to normal summer rain. Isotope ratios of rains and vapors from Hurricane Luis in Puerto Rico decreased as the storm approached. Isotope ratios of rain exhibited an abrupt jump from low values in the eastern half of Puerto Rico to high values farther west which is linked to the storm's rainbands. Isotope ratios of Hurricane Opal's rains reflected the storm's asymmetric structure, with lowest values west of the point of landfall. Record low isotope ratios from a squall line that struck eastern Texas two days before landfall are linked to low-level outflow from Opal and demonstrate that hurricanes can vent enormous quantities of vapor to the surroundings.

  11. Navier slip model of drag reduction by Leidenfrost vapor layers

    KAUST Repository

    Berry, Joseph D.

    2017-10-17

    Recent experiments found that a hot solid sphere that is able to sustain a stable Leidenfrost vapor layer in a liquid exhibits significant drag reduction during free fall. The variation of the drag coefficient with Reynolds number deviates substantially from the characteristic drag crisis behavior at high Reynolds numbers. Measurements based on liquids of different viscosities show that the onset of the drag crisis depends on the viscosity ratio of the vapor to the liquid. Here we attempt to characterize the complexity of the Leidenfrost vapor layer with respect to its variable thickness and possible vapor circulation within, in terms of the Navier slip model that is defined by a slip length. Such a model can facilitate tangential flow and thereby alter the behavior of the boundary layer. Direct numerical and large eddy simulations of flow past a sphere at moderate to high Reynolds numbers (102≤Re≤4×104) are employed to quantify comparisons with experimental results, including the drag coefficient and the form of the downstream wake on the sphere. This provides a simple one parameter characterization of the drag reduction phenomenon due to a stable vapor layer that envelops a solid body.

  12. Dynamic response of vaporizing droplet to pressure oscillation

    Science.gov (United States)

    Yuan, Lei; Shen, Chibing; Zhang, Xinqiao

    2017-02-01

    Combustion instability is a major challenge in the development of the liquid propellant engines, and droplet vaporization is viewed as a potential mechanism for driving instabilities. Based on the previous work, an unsteady droplet heating and vaporization model was developed. The model and numerical method are validated by experimental data available in literature, and then the oscillatory vaporization of n-Heptane droplet exposed to unsteady harmonic nitrogen atmosphere was numerically investigated over a wide range of amplitudes and frequencies. Also, temperature variations inside the droplet were demonstrated under oscillation environments. It was found that the thermal wave is attenuated with significantly reduced wave intensities as it penetrates deep into droplet from the ambient gas. Droplet surface temperature exhibits smaller fluctuation than that of the ambient gas, and it exhibits a time lag with regard to the pressure variation. Furthermore, the mechanism leading to phase lag of vaporization rate with respect to pressure oscillation was unraveled. Results show that this phase lag varies during the droplet lifetime and it is strongly influenced by oscillation frequency, indicating droplet vaporization is only capable of driving combustion instability in some certain frequency domains. Instead, the amplitude of the oscillation does not have very significant effects. It is noteworthy that thermal inertia of the droplet also plays a considerable role in determining the phase lag.

  13. Thermogravimetric study of vapor pressure of TATP synthesized without recrystallization.

    Science.gov (United States)

    Mbah, Jonathan; Knott, Debra; Steward, Scott

    2014-11-01

    This study aims at characterizing the vapor pressure signatures generated by triacetone triperoxide (TATP) that was synthesized without recrystallization by thermogravimmetric analysis (TGA) for exploitation by standoff detection technologies of explosive devices. The thermal behavior of the nonrecrystallized sample was compared with reported values. Any phase change, melting point and decomposition identification were studied by differential scanning calorimeter. Vapor pressures were estimated by the Langmuir method of evaporation from an open surface in a vacuum. Vapor pressures of TATP at different temperatures were calculated using the linear logarithmic relationship obtained from benzoic acid reference standard. Sublimation of TATP was found to follow apparent zero-order kinetics and sublimes at steady rates at 298 K and above. While the enthalpy of sublimation found, 71.7 kJ mol(-1), is in agreement with reported values the vapor pressures deviated significantly. The differences in the vapor pressures behavior are attributable to the synthesis pathway chosen in this study. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. PREVENTION AND CONTROL OF DIMETHYLAMINE VAPORS EMISSION: HERBICIDE PRODUCTION PLANT

    Directory of Open Access Journals (Sweden)

    Zorana Arsenijević

    2008-11-01

    Full Text Available The widely used herbicide, dimethylamine salt of 2,4-dichlorophenoxy acetic acid (2,4-D-DMA, is usually prepared by mixing a dimethylamine (DMA aqueous solution with a solid 2,4-dichlorophenoxy acetic acid (2,4-D. The vapors of the both, reactants and products, are potentially hazardous for the environment. The contribution of DMA vapors in overall pollution from this process is most significant, concerning vapor pressures data of these pollutants. Therefore, the control of the air pollution in the manufacture and handling of methylamines is very important. Within this paper, the optimal air pollution control system in preparation of 2,4-D-DMA was developed for the pesticides manufacturing industry. This study employed the simple pollution prevention concept to reduce the emission of DMA vapors at the source. The investigations were performed on the pilot plant scale. To reduce the emission of DMA vapors, the effluent gases from the herbicide preparation zone were passed through the packed bed scrubber (water - scrubbing medium, and the catalytic reactor in sequence. The end result is a substantially improved air quality in the working area, as well as in the urbanized areas located near the chemical plant.

  15. Navier slip model of drag reduction by Leidenfrost vapor layers

    Science.gov (United States)

    Berry, Joseph D.; Vakarelski, Ivan U.; Chan, Derek Y. C.; Thoroddsen, Sigurdur T.

    2017-10-01

    Recent experiments found that a hot solid sphere that is able to sustain a stable Leidenfrost vapor layer in a liquid exhibits significant drag reduction during free fall. The variation of the drag coefficient with Reynolds number deviates substantially from the characteristic drag crisis behavior at high Reynolds numbers. Measurements based on liquids of different viscosities show that the onset of the drag crisis depends on the viscosity ratio of the vapor to the liquid. Here we attempt to characterize the complexity of the Leidenfrost vapor layer with respect to its variable thickness and possible vapor circulation within, in terms of the Navier slip model that is defined by a slip length. Such a model can facilitate tangential flow and thereby alter the behavior of the boundary layer. Direct numerical and large eddy simulations of flow past a sphere at moderate to high Reynolds numbers (1 02≤Re≤4 ×1 04) are employed to quantify comparisons with experimental results, including the drag coefficient and the form of the downstream wake on the sphere. This provides a simple one parameter characterization of the drag reduction phenomenon due to a stable vapor layer that envelops a solid body.

  16. Characterization of the Dynamics of Vapor Bubble Collapse

    Science.gov (United States)

    Bardia, Raunak; Trujillo, Mario

    2017-11-01

    A numerical/theoretical analysis is presented to characterize the dynamics of a spherical vapor bubble, collapsing at different degrees of severity, controlled and quantified by the nondimensional number, B (introduced by Florschuetz and Chao, 1965). The numerical framework is exercised and validated over the three regimes of bubble collapse, namely, thermal, intermediate, and inertial collapse in increasing order of B. The conventional Rayleigh-Plesset perspective used to discriminate between different regimes, is extended to include the bubble energy balance and jump conditions. It is discovered that the time history of vapor velocity more clearly illustrates the distinctions between the three regimes. For thermal collapse, vapor velocity suffers an initial transient and then equilibrates to nearly zero. At intermediate rates of collapse, the time scales of the process are such that an imbalance occurs between the condensation rate and interface regression rate, which results in a significant magnitude of vapor velocity. At even larger rates of collapse, the time scales become exceedingly small such that the thermal boundary layer is sufficiently thin to provide the necessary heat conduction to balance the large condensation rate, resulting in negligible vapor velocity. National Science Foundation.

  17. Vaporization behavior of non-stoichiometric refractory carbide materials and direct observations of the vapor phase using laser diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.P.; Wantuck, P.J.; Rehse, S.J.; Wallace, T.C. Sr.

    1993-09-01

    Transition metal and actinide carbides, such as ZrC or NbC and UC or ThC, exhibit a wide range of stoichiometry, and therefore vaporize incongruently. At long times, steady state vaporization can be achieved where relative concentrations of atomic species on solid surface equals that in the gas phase. The surface composition under these steady state conditions is termed the congruently vaporizing composition, (CVC). Modeling the vaporization or corrosion behavior of this dynamic process is complex and requires an understanding of how the surface composition changes with time and a knowledge of CVC, which is both temperature and atmosphere dependent. This paper describes vaporization and corrosion behavior of non-stoichiometric refractory carbide materials and, as an example, describes a thermokinetic model that characterizes the vaporization behavior of the complex carbide U{sub x}Zr{sub 1-x}C{sub y} in hydrogen at 2500 to 3200 K. This model demonstrates that steady state corrosion of U{sub x}Zr{sub l-x}C{sub y} is rate limited by gaseous transport of Zr where partial pressure of Zr is determined by CVC. This paper also briefly describes efforts to image and characterize the vapor phase above the surface of ZrC in static and flowing gas environments using planar laser induced fluorescence. We have developed the method for monitoring and controlling the corrosion behavior of nuclear fuels in nuclear thermal rockets. However, the techniques described can be used, to image boundary layers, and could be used verifying corrosion models.

  18. Los valores y las TICS en las instituciones educativas

    OpenAIRE

    Pariente Fragoso, José Luis

    2007-01-01

    La irrupción creciente y acelerada de las tecnologías de la información y las comunicaciones (TICs) en los ámbitos educativos de todos los niveles en el mundo actual, demandan un estudio responsable y acucioso de los efectos que tienen y pueden tener a futuro en la formación de los educandos. Su utilización, con un elevado sentido ético, es una importante tarea que deben enfrentar los responsables de las instituciones educativas, por lo que es imperioso promover modelos de gest...

  19. Los valores y las TICs en las instituciones educativas

    OpenAIRE

    J. L. Pariente Fragoso

    2006-01-01

    La irrupción creciente y acelerada de las tecnologías de la información y las comunicaciones (TICs) en los ámbitos educativos de todos los niveles en el mundo actual, demandan un estudio responsable y acucioso de los efectos que tienen y pueden tener a futuro en la formación de los educandos. Su utilización, con un elevado sentido ético, es una importante tarea que deben enfrentar los responsables de las instituciones educativas, por lo que es imperioso promover modelos de gest...

  20. Las radios universitarias argentinas en las redes sociales

    OpenAIRE

    Milito, Carlos; Casajús, Lucía; Negrin Ferrari, Sonia

    2014-01-01

    El artículo presenta los avances de la investigación que llevamos adelante desde el Taller de Producción Radiofónica I de la Facultad de Periodismo y Comunicación Social de la UNLP. El trabajo se centra en el análisis de las radios universitarias argentinas, nucleadas en la Asociación de Radios Universitarias Argentinas (ARUNA), a fin de conocer cuál es el desarrollo que las mismas están teniendo en la utilización de las redes sociales de la web 2.0. Programa de Incentivos a Docentes Inves...

  1. Technical and environmental aspects of combined cycle power stations with integrated gasification (CCGI); Aspectos tecnicos y medioambientales de las centrales de ciclo combinado con gasificacion integrada (CCGI)

    Energy Technology Data Exchange (ETDEWEB)

    Beltran Mora, Hector Alejandro; Urias Romero, Francisco [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2004-06-15

    liquido a estado gaseoso mediante una oxidacion parcial y el gas obtenido de este proceso se llama gas de sintesis (syngas, por sus siglas en ingles) que es utilizado en Centrales de Ciclo Combinado como sustituto del gas natural. Se muestran tambien los demas componentes de este tipo de centrales como la unidad separadora de aire y se detallan algunas de las modificaciones que se deben de hacer para adaptar una turbina de gas para que utilice syngas y las consideraciones de su integracion con la unidad separadora de aire para optimizar la operacion de la planta. Se muestra una comparacion de valores de eficiencia de las centrales CCGI con las carboeletricas convencionales y con las centrales de ciclo combinado que utilizan gas natural. Finalmente se analizan las emisiones de contaminates de SO{sub 2}, NO{sub x} y CO{sub 2}. Se estudia la posibilidad de utilizar combustibles como coque de petroleo y residuos de vacio que se producen en la refineria de Cadereyta para la posible construccion de una central CCGI en Mexico.

  2. Direct generation of steam and electricity in a open cycle Rankine; Generacion directa de vapor y electricidad en un ciclo Rankine abierto

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Alvaro; Almanza, Rafael; Flores, Vicente [UNAM, Mexico, D.F. (Mexico)

    2000-07-01

    In this work the results of the experimental tests about steam and electricity generation are presented. This work carried out in the solar thermal power plant of the Institute of Engineering with direct steam generation in parabolic through. The global efficiency of the system is studied as for the conversion solar-electricity. The efficiency is determined and it describes the obtaining process of the main plant components, like they are, the solar steam generator, the steam motor and the electric generator. [Spanish] En este trabajo se presentan los resultados de las pruebas experimentales de la generacion de vapor y electricidad realizadas en la planta solar del Instituto de Ingenieria con generacion directa de vapor en concentradores de canal parabolico. Se estudia la eficiencia global del sistema en cuanto a la conversion de energia solar-electricidad. Se determina la eficiencia y describe el proceso de obtencion de la misma y de los principales componentes de la planta como son, el generador de vapor solar, el motor de pistones de vapor y el alternador electrico.

  3. Las aristas del racismo

    Directory of Open Access Journals (Sweden)

    Fredy Rivera Vélez

    2000-01-01

    Full Text Available En el presente trabajo se estudia un ámbito que normalmente se esquiva y se enmascara: Las prácticas racistas. Esta evasión del tema se da en diferentes planos discursivos, y es una práctica, cada vez más frecuente en América Latina, pues aquí se hace de la integración étnica uno de los ejes centrales de la construcción de sus relaciones identitarias y políticas. Se propone, entonces, este trabajo develar la naturaleza y el movimiento de prácticas racistas presentes no sólo discursivamente, en la práctica política, en la práctica laboral, sino que también están presente en nuestra vida cotidiana, bajo nuevas formas y contenidos que se distancian del racismo tradicional e incorpora una nueva gramática racista, una suerte de racismo moderno, no basado en el fenotipo o características físicas como elemento central, sino en un racismo basado en la diferencia cultural, lo cual plantea un plano más excluyente, pues en este planteamiento el “objeto de racismo” no es un objeto de racismo limitado, como en el racismo tradicional, en el cual siempre es utilizado por quien practica el racismo; en el racismo contemporáneo se pretende una ruptura completa y una exclusión total del otro.

  4. New applications of copper vapor lasers in micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.J.; Martinez, M.W.; Warner, B.E.; Dragon, E.P.; Huete, G.; Solarski, M.E.

    1994-11-09

    We have developed a copper vapor laser based micromachinig system using advanced beam quality control and precision wavefront tilting technologies. Precision microdrilling has been demonstrated through percussion drilling and trepanning using this system. With a 30-W copper vapor from running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratio up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250-W copper vapor laser have also been demonstrated with good result. Materialographic sections of machined parts show little (submicron scale) recast layer and heat affected zone.

  5. Rapid and fully automated Measurement of Water Vapor Sorption Isotherms

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Møldrup, Per

    2014-01-01

    Eminent environmental challenges such as remediation of contaminated sites, the establishment and maintenance of nuclear waste repositories, or the design of surface landfill covers all require accurate quantification of the soil water characteristic at low water contents. Furthermore, several...... and pesticide volatilization, toxic organic vapor sorption kinetics, and soil water repellency are illustrated. Several methods to quantify hysteresis effects and to derive soil clay content and specific surface area from VSA-measured isotherms are presented. Besides above mentioned applications, potential...... essential but difficult-to-measure soil properties such as clay content and specific surface area are intimately related to water vapor sorption. Until recently, it was a major challenge to accurately measure detailed water vapor sorption isotherms within an acceptable time frame. This priority...

  6. On the vapor-liquid equilibrium in hydroprocessing reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; Munteanu, M.; Farooqi, H. [National Centre for Upgrading Technology, Devon, AB (Canada)

    2009-07-01

    When petroleum distillates undergo hydrotreating and hydrocracking, the feedstock and hydrogen pass through trickle-bed catalytic reactors at high temperatures and pressures with large hydrogen flow. As such, the oil is partially vaporized and the hydrogen is partially dissolved in liquid to form a vapor-liquid equilibrium (VLE) system with both vapor and liquid phases containing oil and hydrogen. This may result in considerable changes in flow rates, physical properties and chemical compositions of both phases. Flow dynamics, mass transfer, heat transfer and reaction kinetics may also be modified. Experimental observations of VLE behaviours in distillates with different feedstocks under a range of operating conditions were presented. In addition, VLE was predicted along with its effects on distillates in pilot and commercial scale plants. tabs., figs.

  7. Frequency domain fluorimetry using a mercury vapor lamp

    Science.gov (United States)

    Bohn, Matthew J.; Lundin, Michael A.; Marciniak, Michael A.

    2009-04-01

    Frequency Domain (FD) fluorimetry, capitalizes on the frequency response function of a fluorophore and offers independence from light scatter and excitation/emission intensity variations in order to extract the sample's fluorescent lifetime. Mercury vapor lamps, a common source of industrial facility lighting, emit radiation that overlaps the UV/blue absorption spectrum of many fluorophores and may be used as an efficient and portable excitation source. The AC power modulation of mercury vapor lamps modulates the lamp's intensity at 120 Hz (in the United States) and higher harmonics. The fluorescent lifetimes for 3 different materials (willemite, uranium doped glass and U3O8) are measured with conventional techniques and compared with the FD technique using the power harmonics from a mercury vapor lamp. The mercury lamp measurements agree to within 25% of the conventional methods.

  8. Simulation of melting and vaporization of metals at hypervelocity impact

    Energy Technology Data Exchange (ETDEWEB)

    Povarnitsyn, M E; Khishchenko, K V; Levashov, P R [Joint Institute for High Temperature, Russian Academy of Sciences, 13/19 Izhorskaya, Moscow 125412 (Russian Federation)], E-mail: povar@ihed.ras.ru

    2008-02-15

    Simulations of experiments on shock-induced melting, fragmentation and vaporization in aluminum and zinc targets are presented. A titanium impactor moves at a velocity of 10.4 km/s and causes melting of these materials in a shock wave. Under rarefaction thermodynamic path crosses the liquid-vapor coexistence boundary and enters into metastable liquid region. Liquid in a metastable state may undergo either liquid-vapor phase separation or mechanical fragmentation. Homogeneous nucleation theory and mechanical fragmentation criterion of Grady are taken into account to control the kinetics of these processes in our model. The first effect dominates in the vicinity of the critical point, the second one - at lower temperatures. Analysis of phase transitions and kinetics of phase separation is performed using thermodynamically complete equation of state with allowance for stable and metastable regions for all materials under consideration.

  9. Using vapor phase tomography to measure the spatial distribution of vapor concentrations and flux for vadose-zone VOC sources.

    Science.gov (United States)

    Mainhagu, J; Morrison, C; Brusseau, M L

    2015-01-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Indirect heating of natural gas using vapor chambers; Aquecimento indireto de gas natural com uso de camaras de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Milanez, Fernando H.; Mantellil, Marcia H.B.; Borges, Thomaz P.F. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica; Landa, Henrique G. de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2005-07-01

    Operation safety and reliability are major guidelines in the design of city-gate units. Conventional natural gas heaters operate by a indirect mechanism, where liquid water is used to transfer heat by natural convection between the combustion chamber and the natural gas coil. In this work, the concept of vapor chamber is evaluated as an indirect gas heater. In a vapor chamber, liquid water is in contact with the heat source, and vaporizes. The vapor condenses in contact with the heat sink. A reduced scale model was built and tested in order to compare these two heating concepts where the combustion chamber was replaced by electrical cartridge heaters. This engineering model can operate either as a conventional heater or as a vapor chamber. The comparison between the concepts was done by inducing a controlled power to the cartridges and by measuring the resulting temperature distributions. In the novel design, the heat exchanger efficiency increases, and the thermal inertia decreases, compared to the conventional system. The new sealed concept of the chamber prevents water evaporation losses. (author)

  11. Dejar las lagrimas e ir hacia las acciones

    DEFF Research Database (Denmark)

    Jeppesen, Anne Marie Ejdesgaard

    2015-01-01

    Este artículo enfoca en la frontera entre México y los Estados Unidos, las condiciones especiales de la sociedad fronteriza, las economías interconectadas y la violencia, en especial la violencia ejercida contra mujeres y los feminicidios. El artículo discute diferentes perspectivas y maneras de ...... comprender la violencia enfocando en una ciudad concreta, Ciudad Juárez. El material usado es mexicano pero también se incluyen otros estudios. El concepto de Judith Butler, ‘vidas precarias’ es utilizada para discutir la violencia......Este artículo enfoca en la frontera entre México y los Estados Unidos, las condiciones especiales de la sociedad fronteriza, las economías interconectadas y la violencia, en especial la violencia ejercida contra mujeres y los feminicidios. El artículo discute diferentes perspectivas y maneras de...

  12. Disinfection and dewatering of wastewater solids by interstitial vapor generation.

    Science.gov (United States)

    Kramer, Timothy A; Hill, T Keith; Beckley, John

    2004-01-01

    Disinfection of wastewater solids (waste activated solids [WAS]) by interstitial vapor generation was investigated. In addition to the magnitude of disinfection, the amount of water removed and cost relative to traditional residuals disinfection processes was also examined. The process of interstitial vapor generation occurs as a result of the rapid heating of liquid in the interstices of the solid-liquid array. Intense heating causes boiling of the slurry liquid, resulting in an expanding vapor front that simultaneously dewaters the wastewater solids and contributes to the destruction of viable pathogenic microorganisms. Objectives of the study were threefold: (1) to validate disinfection of WAS using the interstitial vapor technique; (2) establish the degree of possible drying of the residuals using the techniques; and (3) establish the key operating variables for the process. Results showed a significant reduction in the most probable number of total coliforms and Escherichia coli (E. coli). Specifically, greater than four-log unit reductions were produced for both total coliform and E. coli bacteria. In addition to quantifying the reduction in bacteria, the percent solids were increased from an initial amount of 7.6% (mass basis) to a final solids content greater than 90% using optimal processing conditions. Cost comparisons were also conducted and shown to be quite favorable when compared with traditional disinfection methods such as lime addition. Because of the high level of E. coli reduction achieved, the process of interstitial vapor generation is shown to be capable of converting a class B biosolids into a class A pathogen reduced product. For example, an initial most probable number (MPN) of 1.2 x 10(6) E. coli bacteria were reduced to 19 at the extreme conditions of the process, well below the requirement of an MPN of 1000 for fecal coliform bacteria. Given its ability to disinfect and dewater wastewater solids, the interstitial vapor generation process

  13. Removal of gasoline vapors from air streams by biofiltration

    Energy Technology Data Exchange (ETDEWEB)

    Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

    1993-03-01

    Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40[degrees]C temperature range with removal being completely inhibited at 54[degrees]C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

  14. Removal of gasoline vapors from air streams by biofiltration

    Energy Technology Data Exchange (ETDEWEB)

    Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

    1993-03-01

    Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40{degrees}C temperature range with removal being completely inhibited at 54{degrees}C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

  15. Latent fingermark development using low-vacuum vaporization of ninhydrin.

    Science.gov (United States)

    Chen, Chun-Chieh; Yang, Chao-Kai; Liao, Jeh-Shane; Wang, Sheng-Meng

    2015-12-01

    The vacuum technique is a method of vaporizing a solid material to its gas phase, helping deposit reagents gently on target surfaces to develop latent fingermarks. However, this application is rarely reported in the literature. In this study, a homemade fume hood with a built-in vacuum control system and programmable heating system designed by the Taiwan Criminal Investigation Bureau is introduced. Factors that affect the instrument's performance in developing fingermarks are discussed, including the quantity of chemicals for vaporization, heating program arrangement, and paper of different materials. The results show that fingermarks are effectively developed by vaporizing solid ninhydrin. This would be an alternative application in selecting a solvent-free method for protecting the environment and reducing health hazards in the lab. In terms of the heating program, the result indicates that under a low-vacuum condition (50 mTorr), 80-90 °C is a suitable temperature range for ninhydrin vaporization, allowing ninhydrin to be vaporized without bumping and waste. In terms of the performance on different material papers, this instrument demonstrates its capacity by developing latent fingermarks on thermal paper without discoloration or damaging the original writing, and the same results are also observed on Taiwan and United States banknotes. However, a coherent result could be hardly obtained using the same vaporization setting because different banknotes have their own surface features and water absorption ability or other unique factors may influence the effect of ninhydrin deposition. This study provides a reliable application for developing latent fingermarks without using solvents, and it is also expected to contribute to environmental protection along with the trend of green chemistry technology. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Carbonyl Compounds Produced by Vaporizing Cannabis Oil Thinning Agents.

    Science.gov (United States)

    Troutt, William D; DiDonato, Matthew D

    2017-11-01

    Cannabis use has increased in the United States, particularly the use of vaporized cannabis oil, which is often mixed with thinning agents for use in vaporizing devices. E-cigarette research shows that heated thinning agents produce potentially harmful carbonyls; however, similar studies have not been conducted (1) with agents that are commonly used in the cannabis industry and (2) at temperatures that are appropriate for cannabis oil vaporization. The goal of this study was to determine whether thinning agents used in the cannabis industry produce potentially harmful carbonyls when heated to a temperature that is appropriate for cannabis oil vaporization. Four thinning agents (propylene glycol [PG], vegetable glycerin [VG], polyethylene glycol 400 [PEG 400], and medium chain triglycerides [MCT]) were heated to 230°C and the resulting vapors were tested for acetaldehyde, acrolein, and formaldehyde. Each agent was tested three times. Testing was conducted in a smoking laboratory. Carbonyl levels were measured in micrograms per puff block. Analyses showed that PEG 400 produced significantly higher levels of acetaldehyde and formaldehyde than PG, MCT, and VG. Formaldehyde production was also significantly greater in PG compared with MCT and VG. Acrolein production did not differ significantly across the agents. PG and PEG 400 produced high levels of acetaldehyde and formaldehyde when heated to 230°C. Formaldehyde production from PEG 400 isolate was particularly high, with one inhalation accounting for 1.12% of the daily exposure limit, nearly the same exposure as smoking one cigarette. Because PG and PEG 400 are often mixed with cannabis oil, individuals who vaporize cannabis oil products may risk exposure to harmful formaldehyde levels. Although more research is needed, consumers and policy makers should consider these potential health effects before use and when drafting cannabis-related legislation.

  17. Microstructure of vapor deposited coatings on curved substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G., E-mail: haydn@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., P.O. Box 400745, Charlottesville, Virginia 22904 (United States)

    2015-09-15

    Thermal barrier coating systems consisting of a metallic bond coat and ceramic over layer are widely used to extend the life of gas turbine engine components. They are applied using either high-vacuum physical vapor deposition techniques in which vapor atoms rarely experience scattering collisions during propagation to a substrate, or by gas jet assisted (low-vacuum) vapor deposition techniques that utilize scattering from streamlines to enable non-line-of-sight deposition. Both approaches require substrate motion to coat a substrate of complex shape. Here, direct simulation Monte Carlo and kinetic Monte Carlo simulation methods are combined to simulate the deposition of a nickel coating over the concave and convex surfaces of a model airfoil, and the simulation results are compared with those from experimental depositions. The simulation method successfully predicted variations in coating thickness, columnar growth angle, and porosity during both stationary and substrate rotated deposition. It was then used to investigate a wide range of vapor deposition conditions spanning high-vacuum physical vapor deposition to low-vacuum gas jet assisted vapor deposition. The average coating thickness was found to increase initially with gas pressure reaching a maximum at a chamber pressure of 8–10 Pa, but the best coating thickness uniformity was achieved under high vacuum deposition conditions. However, high vacuum conditions increased the variation in the coatings pore volume fraction over the surface of the airfoil. The simulation approach was combined with an optimization algorithm and used to investigate novel deposition concepts to tailor the local coating thickness.

  18. Las multitudes y las revoluciones de nuestro tiempo

    Directory of Open Access Journals (Sweden)

    John Harold Biervliet

    2015-08-01

    Full Text Available Este artículo examina el motivo de las multitudes y las revoluciones de nuestro tiempo. Primeramente, se discuten las diferencias entre los conceptos de multitud y masa. Así, podemos considerar las revoluciones como acontecimientos de cambios sociales, económicos y políticos, provenientes de las clases baja y media de la sociedad. El meollo de este artículo refiere a la dignidad humana articulada a la contracción de los Estados de bienestar. Los ciudadanos están reflejando un desencanto hacia la clase política y una frustración con respecto al empeoramiento de las condiciones económicas y sociales. Podemos observar los casos de indignados en Grecia, España y Portugal pero también en los países árabes. De esta misma manera, las revoluciones de las multitudes siguen avanzando por medio de las demostraciones públicas y protestas sobre los espacios geográficos. Finalmente, las dinámicas de cambio a través de las revoluciones árabes son una cuestión compleja debido al círculo vicioso entre la tendencia autoritaria y la islámica. This article examines the reason of multitudes and revolutions in our time. First of all, it discusses the difference between the concept of multitude and mass. Consequently, revolutions can be considered as social, economic, and political events of changes, which come from the low and middle classes of the society. This article refers to the human dignity articulated with the contraction of Welfare states. Citizens are reflecting disenchantment towards the political class and frustration regarding the deterioration of social and economic conditions. We can observe angry people in Greece, Spain, and Portugal but also in Arabian countries. In this same way, revolutions of multitudes continue by means of public demonstrations and protests on geographical spaces. Finally, the dynamics of change through Arabian Revolutions are a complex matter due to the vicious circle between the authoritarian or Islamic

  19. Utilizacion de las TIC y su impacto en la competitividad de las empresas latinoamericanas

    National Research Council Canada - National Science Library

    Scheel Mayenberger, Carlos; Rivera Gonzalez, Angel Eustorgio

    2009-01-01

    .... Para que las TIC sean un habilitador diferenciador de las organizaciones, es necesario concentrar su utilizacion en las competencias claves de negocio de las empresas y articularlas en conjunto...

  20. Aircraft measurements of CO{sub 2}, O{sub 3}, water vapor, aerosol fluxes and, turbulence over Lake Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Alkezweeny, A. J. [Geophysical Institute, University of Alaska, Fairbanks (United States)

    1996-04-01

    Using an instrumented aircraft we made a constant altitude flight over lake Michigan near the Chicago Shoreline and about 50 km downwind of it. The flight was made on June 18, 1992 between about 1:30 and 3:30 pm. The wind was southwesterly averaged about 12 m s{sup -}1. Employing the eddy correlation method we calculated the fluxes of CO{sub 2}, O{sub 3}, water vapor and aerosols in the diameter range of 0.1 to 3.0 {mu}m. The fluxes near the shoreline were found to be significantly higher than those in the middle of the lake. The fluxes near the shoreline for O{sub 3} and aerosols were directed toward the surface and corresponding to transfer (deposition) velocities of 0.15 cm s{sup -}1 and 0.86 cm s{sup -}1, respectively. For CO{sub 2}, and water vapor, the fluxes were directed upward and corresponding to transfer velocities of 0.04 cm s{sup -}1 and 0.54 cm s{sup -}1, respectively. At mid-lake the fluxes of O{sub 3} and water vapor were directed upward and corresponding to transfer velocity of 0.045 cm s{sup -}1 and 0.003 cm s{sup -}1. For CO{sub 2} and aerosols the fluxes were directed downward and corresponding to transfer (deposition) velocities of 0.006 cm s{sup -}1 and 0.226 cm s{sup -}1. [Spanish] Con un a vion dotado de instrumentos hicimos un vuelo a altura constante sobre el lago Michigan cerca de la linea de costa y 50 km, aproximadamente, viento abajo de ella. El vuelo fue hecho en junio 18 de 1992 entre las 1:30 y las 3:30 p.m. El viento era del suroeste 12 ms{sup -}1 en promedio. Empleando el metodo de correlacion torbellinaria calculamos los fluidos de CO{sub 2} y O{sub 3}, vapor de agua y aerosoles en una gama de diametros de 0.1 a 3.0 {mu}m. Se encontro que los flujos cerca de la costa eran significativamente mas altos que en medio del lago. Los flujos del O{sub 3} y aerosoles cerca de la costa estaban dirigidos hacia la superficie y correspondian a las velocidades de transporte (depositacion) de 0.15 cm s{sup -}1 y 0.45 cm s{sup -}1

  1. Efectividad en las redes empresariales

    OpenAIRE

    Álvarez Rey, Natalia; Correal López, Ana María; García Algarra, Laura Ximena

    2014-01-01

    Este estudio tiene como objetivo identificar cuáles son las variables que repercuten en la efectividad de las redes empresariales. Esto, con base en la búsqueda de literatura existente de la efectividad en equipos, en organizaciones y en las redes interorganizacionales, así como el análisis de modelos y estudios empíricos que permitieron el análisis. De acuerdo con la búsqueda, se encontró que variables como la estructura de la red, la estabilidad del sistema, el compromiso de los empleados e...

  2. LAS COMPETENCIAS PROFESIONALES DEL INVESTIGADOR

    OpenAIRE

    FERNÁNDEZ, FABIOLA MARÍA VALIENTE

    2011-01-01

    Este trabajo aborda el tema competencias profesionales del investigador, tutor de tesis. El principal objetivo de esta Monografía consiste en determinar las competencias profesionales que debe poseer el investigador como tutor de tesis. Al respecto se aborda el problema de las competencias profesionales del tutor de tesis. Se analiza su perfil profesional, sus condiciones y cualidades personales, como así también, las funciones específicas que desempeña en la práctica de su rol. El estudio co...

  3. Unificar las ciencias del deporte

    Directory of Open Access Journals (Sweden)

    Natàlia Balagué Serre

    2013-12-01

    Full Text Available El deporte no es solo un fenómeno social de nuestro mundo, sino que también es un campo privilegiado para el estudio del comportamiento social y humano. Durante las últimas décadas, se ha producido un enorme crecimiento y especialización de las ciencias del deporte y el lema del 18º Congreso del European College of Sport Sciences (ECSS “Unificar las ciencias del deporte” representa desafiar este proceso de fragmentación. El lema conlleva un cambio de la especialización a la integración, de una concepción de los sistemas vivos basada en la teoría de la información y la ingeniería a una de base biológica, de la investigación multidisciplinaria a la transdisciplinaria. Pero aparece una pregunta: ¿es posible integrar las áreas fragmentadas y facilitar la transferencia de los principios explicativos teóricos, técnicas y perspectivas metodológicas entre disciplinas? En el marco de las contribuciones hechas en el congreso, este artículo tiene como objetivo introducir enfoques científicos ya extendidos en los ámbitos de la física, la química, la biología (incluyendo las ómicas y las ciencias sociales, y que centradas en las interacciones dinámicas complejas de los componentes sistémicos (proteínas, células, organismos, grupos, sociedades, revelan principios explicativos generales que contribuyen a la unificación del conocimiento. Intentamos animar a las personas interesadas en las ciencias del deporte a percibir nuevas formas de investigación y a complementar, sin sustituirlos, los enfoques dominantes, con la esperanza de que ir de las partes al todo y del todo a las partes ayudará a los científicos a reconocer los caminos más adecuados.

  4. Superheating effects in line broadening of dense alkali vapors

    Science.gov (United States)

    Pichler, G.; Makdisi, Y.; Kokaj, J.; Mathew, J.; Rakić, M.; Beuc, R.

    2017-02-01

    We used the superheating of the dense alkali vapor in order to separate atomic from the molecular photoionization spectrum. Homonuclear and heteronuclear alkali molecules are essentially two electron systems and therefore simultaneous excitation of two atoms above the ionization limit will form autoionizing potential curves which will bring about new bands in the photoionization spectrum. We present a satisfactory comparison between experimental and theoretical emission coefficient function of diffuse bands (cesium dimer excimer) at temperatures up to 1000 °C, where the metal vapor was heavily superheated. New results for Rb2 photoionization process reveal similar structured photoionization continuum but with reduced number of photoionization bands.

  5. A rubidium vapor source for a plasma source for AWAKE

    Science.gov (United States)

    Plyushchev, G.; Kersevan, R.; Petrenko, A.; Muggli, P.

    2018-01-01

    We present the scheme for a rubidium vapor source that is used as a plasma source in the AWAKE plasma wakefield acceleration experiment. The plasma wakefield acceleration process requires a number of stringent parameters for the plasma: electron density adjustable in the (1–10)  ×  10 14 cm‑3 range, 0.25% relative density uniformity, sharp (the beginning the plasma column. We show with analytical and direct simulation Monte Carlo results that the rubidium density in the proposed source should meet these requirements. Laser ionization then transfers the above neutral vapor parameters to the plasma.

  6. Method And Apparatus For Atomizing And Vaporizing Liquid

    KAUST Repository

    Lal, Amit

    2014-09-18

    A method and apparatus for atomizing and vaporizing liquid is described. An apparatus having an ejector configured to eject one or more droplets of liquid may be inserted into a reservoir containing liquid. The ejector may have a vibrating device that vibrates the ejector and causes liquid to move from the reservoir up through the ejector and out through an orifice located on the top of the ejector. The one or more droplets of liquid ejected from the ejector may be heated and vaporized into the air.

  7. Dimensionamiento de los circuitos de vapor de un buque tanque.

    OpenAIRE

    Pintilie, Cosmin

    2015-01-01

    El presente proyecto tiene como objetivo general el estudio del sistema de vapor de un buque desde el generador de vapor, pasando por el sistema de distribución hasta llegar a los consumidores. Entre los enfoques del proyecto, se buscarán los factores que provocan pérdidas en un sistema de calentamiento y se propondrán soluciones para evitar o disminuir tales pérdidas. Como objetivo principal, se determinará qué sistema generador debe llevar el buque en cuestión, y el modo de distribución del...

  8. Energy balance in laser-irradiated vaporizing droplets.

    Science.gov (United States)

    Zardecki, A; Armstrong, R L

    1988-09-01

    The interactions of vaporizing aerosols with a high energy laser beam are analyzed in the diffusive vaporization regime. This is the regime in which diffusive mass transport and conductive energy transport dominate the aerosol-beam interactions. A numerical analysis of the coupled aerosol-beam equations allows us to compute the energy conversion of the incident laser pulse. The plots showing the functional form of the pulse shape and the fractional energy conversion are given to illustrate the interactions for a wide range of pulse energies. A new term describing the droplet radius shrinking in time, similar in form to that recently analyzed by Davies and Brock, is included.

  9. Fluid metals the liquid-vapor transition of metals

    CERN Document Server

    Hensel, Friedrich

    2014-01-01

    This is a long-needed general introduction to the physics and chemistry of the liquid-vapor phase transition of metals. Physicists and physical chemists have made great strides understanding the basic principles involved, and engineers have discovered a wide variety of new uses for fluid metals. Yet there has been no book that brings together the latest ideas and findings in the field or that bridges the conceptual gap between the condensed-matter physics relevant to a dense metallic liquid and the molecular chemistry relevant to a dilute atomic vapor. Friedrich Hensel and William Warren seek

  10. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

    Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan

    volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar...... are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  11. How do organic vapors contribute to new-particle formation?

    CERN Document Server

    Donahue, Neil M; Chuang, Wayne; Riipinen, Ilona; Riccobono, Francesco; Schobesberger, Siegfried; Dommen, Josef; Baltensperger, Urs; Kulmala, Markku; Worsnop, Douglas R; Vehkamaki, Hanna

    2013-01-01

    Highly oxidised organic vapors can effectively stabilize sulphuric acid in heteronuclear clusters and drive new-particle formation. We present quantum chemical calculations of cluster stability, showing that multifunctional species can stabilize sulphuric acid and also present additional polar functional groups for subsequent cluster growth. We also model the multi-generation oxidation of vapors associated with secondary organic aerosol formation using a two-dimensional volatility basis set. The steady-state saturation ratios and absolute concentrations of extremely low volatility products are sufficient to drive new-particle formation with sulphuric acid at atmospherically relevant rates.

  12. CONDENSATION OF WATER VAPOR IN A VERTICAL TUBE CONDENSER

    Directory of Open Access Journals (Sweden)

    Jan Havlík

    2015-10-01

    Full Text Available This paper presents an analysis of heat transfer in the process of condensation of water vapor in a vertical shell-and-tube condenser. We analyze the use of the Nusselt model for calculating the condensation heat transfer coefficient (HTC inside a vertical tube and the Kern, Bell-Delaware and Stream-flow analysis methods for calculating the shell-side HTC from tubes to cooling water. These methods are experimentally verified for a specific condenser of waste process vapor containing air. The operating conditions of the condenser may be different from the assumptions adopted in the basic Nusselt theory. Modifications to the Nusselt condensation model are theoretically analyzed.

  13. Daytime Raman lidar for water vapor and ozone concentration measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Hyeon; Cha, Hyung Ki; Lee, Jong Min [Laboratory for QuantumOptics, Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of); Veselovskii, I. [Physcis Instrumentation Center of General Physcis Institute, Moscow (Russian Federation)

    1996-11-15

    A Raman lidar system based on a quadrupled Nd : Yagi laser monitors the Raman signals from N{sub 2}, O{sub 2} and H{sub 2}O molecules. To suppress the elastic backscatter, a specially designed liquid absorption edge filter is used. The water vapor concentration is calculated from the radio of water and nitrogen Raman signals. Ozone concentration is evaluated from nitrogen and oxygen Raman returns by applying Dial technique. The obtained ozone profiles can be used for water vapor data correction.

  14. The Commercial Vapor Diffusion Apparatus (CVDA) STS-95

    Science.gov (United States)

    2004-01-01

    The Commercial Vapor Diffusion Apparatus will be used to perform 128 individual crystal growth investigations for commercial and science research. These experiments will grow crystals of several different proteins, including HIV-1 Protease Inhibitor, Glycogen Phosphorylase A, and NAD Synthetase. The Commercial Vapor Diffusion Apparatus supports multiple commercial investigations within a controlled environment. The goal of the Commercial Protein Crystal Growth payload on STS-95 is to grow large, high-quality crystals of several different proteins of interest to industry, and to continue to refine the technology and procedures used in microgravity for this important commercial research.

  15. Chemical Vapor Deposition of Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Haven, Victor E.

    1999-01-01

    Ceramic thermal barrier coatings extend the operating temperature range of actively cooled gas turbine components, therefore increasing thermal efficiency. Performance and lifetime of existing ceram ic coatings are limited by spallation during heating and cooling cycles. Spallation of the ceramic is a function of its microstructure, which is determined by the deposition method. This research is investigating metalorganic chemical vapor deposition (MOCVD) of yttria stabilized zirconia to improve performance and reduce costs relative to electron beam physical vapor deposition. Coatings are deposited in an induction-heated, low-pressure reactor at 10 microns per hour. The coating's composition, structure, and response to the turbine environment will be characterized.

  16. La intangibilidad de las acciones privadas de las personas

    Directory of Open Access Journals (Sweden)

    Mauricio Maldonado Muñoz

    2014-03-01

    Full Text Available En este artículo pretendemos acercarnos a una garantía que —siguiendo cierta doctrina— hemos llamado: intangibilidad de las acciones privadas de las personas. Desde una visión que busca ser omnicomprensiva, se analizan las fuentes de las que mana la privacidad y, posteriormente, su contenido y alcances. Sobre todo, se analiza el problema de los límites de la injerencia y regulación estatal, partiendo de una posición que niega las visiones comunitaristas. En general, se trata de conceptualizar a la garantía planteada desde el punto de vista de la libertad, el derecho y las virtudes humanas, los derechos de terceros y la moral pública; concretando su vinculación con otros derechos relacionados con la privacidad. La idea central del presente trabajo consiste en demostrar la transversalidad de la garantía señalada, implicando —en ese proceso— cuestiones trascendentes para la filosofía del derecho, la teoría del derecho y, por supuesto, para el estudio del derecho de los derechos humanos. 

  17. Estudio de corrosión bajo tensión en los aceros inoxidables 17-4PH y 17-7PH en presencia de NaCl y NaOH (20 % a 90 °C

    Directory of Open Access Journals (Sweden)

    Gaona-Tiburcio, Citlalli

    2000-04-01

    Full Text Available One of the problems that affects to the electric industry is the not programmed stoppages in the power plants, due to the failure of any main component: boiler, turbine and generator. In the turbine, the combined action of a corrosive agent (humid polluted vapor and a mechanical effort generally will result in Stress Corrosion Cracking (SCC. In this work the SCC susceptibility of the precipitation hardening stainless steels 17-4PH and 17- 7PH, thoroughly used in steam turbine blades of power stations is analyzed. The specimens were tested in the presence of NaCl and NaOH (20 % to 90 °C and different pH. The CERT test (Constant Extension Rate Test was used, at 10-6 s-1 supplementing it with electrochemical noise; the aim was to identify the conditions of maximum susceptibility and the performance of the studied materials. The fractographic analysis revealed ductile and brittle fracture. Intergranular crackings, characteristic of the anodic dissolution mechanism of the material was observed. Nevertheless, the main mechanism responsible the failure was hydrogen embrittlement.

    Uno de los problemas que afecta a la industria eléctrica es el de los paros no programados en las plantas generadoras de electricidad, debidos al fallo de algún componente principal: caldera, turbina y generador. En la turbina, la acción combinada de un agente corrosivo (vapor húmedo contaminado y un esfuerzo mecánico, generalmente provocará corrosión bajo tensión (CBT. En este trabajo se analiza la susceptibilidad a la CBT de los aceros inoxidables, endurecibles por precipitación, 17-4PH y 17-7PH, ampliamente usados en alabes de turbina de vapor de centrales termoeléctricas. Las muestras se ensayaron en presencia de NaCl y NaOH (20 % a 90 °C, y distintos valores de pH. Se empleó el ensayo CERT (Constant Extensión Rate Test, a velocidades de 10-6 s-1, complementándolo con ruido electroquímico, buscando

  18. Treatment of vulvar intraepithelial neoplasia with CO(2) laser vaporization and excision surgery.

    Science.gov (United States)

    Leufflen, Léa; Baermann, Pauline; Rauch, Philippe; Routiot, Thierry; Bezdetnava, Lina; Guillemin, Francois; Desandes, Emmanuel; Marchal, Frederic

    2013-10-01

    To evaluate the recurrence rate after a single treatment of vulvar intraepithelial neoplasia (VIN) with CO(2) laser vaporization. Fifty women with usual-type or differentiated VIN (grades 2 and 3) treated with CO(2) laser vaporization or surgery excision (cold knife or CO(2) laser) were retrospectively evaluated. Of the 50 patients, 41 (82.0%) had usual-type VIN and 9 (18.0%) had differentiated VIN. Moreover, 24 (48.0%) were treated with surgery excision and 26 (52.0%) underwent CO(2) laser vaporization. Laser-treated patients were significantly younger (p vaporization groups (p vaporization treatment (p vaporization requires regular, close, and extended monitoring.

  19. Heat and mass transfer and friction resistance of forced superheated vapor flow in tubes

    Energy Technology Data Exchange (ETDEWEB)

    Grebennikov, V.N.

    This paper describes a procedure used for calculating the heat/mass transfer and friction resistance of a forced superheated vapor flow in tubes of separators-vapor superheaters and direct-flow vapor generators under equilibrium conditions and also under conditions where the flow is in a thermodynamic nonequilibrium state. Using the Reynolds analogy-based concept, an analysis of the process is carried out. Recommendations for calculating the heat/mass transfer and the hydraulic characteristics of vapor- superheating sections in separators-vapor superheaters and direct-flow vapor generators are made.

  20. Las cinco grandes dimensiones de la personalidad

    Directory of Open Access Journals (Sweden)

    Jan ter Laak

    1996-12-01

    Full Text Available Este artículo revisa las distintas posiciones teóricas sobre las cinco grandes dimensiones de la personalidad, mostrando las semejanzas y diferencias entre las posturas teóricas. Esta contribución presenta lo siguiente: (a la génesis del contenido y la estructura de las cinco dimensiones; (b la fortaleza de las cinco dimensiones; (e la relación de las cinco grandes dimensiones con otros constructos de personalidad; (d discute el valor predictivo de las puntuaciones del perfil de las cinco dimensiones para criterios pertinentes; (e analiza el estatus teórico de las cinco dimensiones; (f discute críticas históricas sobre las cinco grandes dimensiones y se formulan respuestas a estas críticas; (g hace conjeturas para el futuro de las cinco grandes dimensiones; y (h concluye con algunas conclusiones y comentarios.

  1. Determination of some refractory elements and Pb by fluorination assisted electrothermal vaporization inductively coupled plasma mass spectrometry with platform and wall vaporization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuefei; Hu Bin, E-mail: binhu@whu.edu.cn

    2011-02-15

    Platform and wall vaporization for electrothermal vaporization (ETV)-inductively coupled plasma mass spectrometry (ICP-MS) determination of some refractory elements (Ti, V, Cr, Mo, La and Zr) and Pb were comparatively studied with the use of poly (tetrafluoroethylene) (PTFE) as fluorinating reagent. The factors affecting the vaporization behaviors of the target analytes in the platform and tube wall vaporization including vaporization temperature and time, pyrolytic temperature and time were studied in detail, and the flow rates of carrier gas/auxiliary carrier gas, were carefully optimized. Under the optimal conditions, the signal profiles, signal intensity, interferences of coexisting ions and analytical reproducibility for wall and platform vaporization ETV-ICP-MS were compared. It was found that both wall and platform vaporization could give very similar detection limits, but the platform vaporization provided higher signal intensity and better precision for some refractory elements and Pb than the wall vaporization. Especially for La, the signal intensity obtained by platform vaporization was 3 times higher than that obtained by wall vaporization. For platform vaporization ETV-ICP-MS, the limits of detection (LODs) of 0.001 {mu}g L{sup -1} (La) {approx} 0.09 {mu}g L{sup -1} (Ti) with the relative standard deviations (RSDs) of 1.5% (Pb) {approx} 15.5% (Zr) were obtained. While for wall vaporization ETV-ICP-MS, LODs of 0.005 {mu}g L{sup -1} (La) {approx} 0.4 {mu}g L{sup -1} (Pb) with RSDs of 3.2% (Mo) {approx} 12.8% (Zr) were obtained. Both platform and tube wall vaporization techniques have been used for slurry sampling fluorination assisted ETV-ICP-MS direct determination of Ti, V, Cr, Mo, La, Zr and Pb in certified reference materials of NIES No. 8 vehicle exhaust particulates and GBW07401 soil, and the analytical results obtained are in good agreement with the certified values.

  2. Las Vegas Floodplain Management Study

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The City of Las Vegas and the Tierra y Montes Soil and Water Conservation District requested the Natural Resources Conservation Service (NRCS) to conduct a study of...

  3. Los cambios en las organizaciones

    National Research Council Canada - National Science Library

    Téllez, Marien González

    2011-01-01

    El mundo que nos rodea está sometido a constantes cambios, las organizaciones son parte de ellos y blanco de todos los sucesos del mundo circundante, como parte del sistema abierto en constante interrelación que componen...

  4. Uso de la generación de vapores en la determinación de metales traza por técnicas atómicas

    OpenAIRE

    Villanueva Alonso, Julia

    2012-01-01

    La generación de vapor es una técnica de introducción de muestra que ha sido empleada para incrementar la sensibilidad en la determinación de los elementos que forman hidruros usando diferentes técnicas espectroscópicas como AAS. (Espectroscopía de Absorción Atómica), AFS (Espectroscopía de Fluorescencia Atómica) o ICPOES (Espectroscopía de Emisión Óptica con fuente de Plasma de Acoplamiento Inductivo). En las últimas décadas la aplicación de la generación de vapor se ha amp...

  5. Descolonizando las noticias. Un acercamiento a las narrativas de la violencia contra las mujeres

    Directory of Open Access Journals (Sweden)

    Yanet Martínez

    2016-09-01

    Full Text Available El objetivo fundamental de este artículo es compartir una reflexión teórica y metodológica acerca de las narrativas mediáticas de la violencia contra las mujeres desde una perspectiva feminista descolonial. Este documento es el resultado del diálogo entre el trabajo empírico en el análisis de noticias y las corrientes teóricas que articulan feminismo y comunicación.

  6. Prediction of vapor pressure and heats of vaporization of edible oil/fat compounds by group contribution

    DEFF Research Database (Denmark)

    Ceriani, Roberta; Gani, Rafiqul; Liu, Y.A.

    2013-01-01

    In the present work, a group contribution method is proposed for the estimation of vapor pressures and heats of vaporization of organic liquids found in edible fat/oil and biofuel industries as a function of temperature. The regression of group contribution parameters was based on an extensive...... databank (2036 values) composed by fatty compounds, i.e., fatty acids, methyl-, ethyl-, propyl- and butyl- esters, fatty alcohols, tri-, di- and monoacylglycerols and hydrocarbons. This new methodology gives improved predictions when compared to a prior group contribution equation (Ceriani and Meirelles...

  7. Graphene by one-step chemical vapor deposition from ferrocene vapors: Properties and electrochemical evaluation

    Science.gov (United States)

    Pilatos, George; Perdikaki, Anna V.; Sapalidis, Andreas; Pappas, George S.; Giannakopoulou, Tatiana; Tsoutsou, Dimitra; Xenogiannopoulou, Evangelia; Boukos, Nikos; Dimoulas, Athanasios; Trapalis, Christos; Kanellopoulos, Nick K.; Karanikolos, Georgios N.

    2016-02-01

    Growth of few-layer graphene using ferrocene as precursor by chemical vapor deposition is reported. The growth did not involve any additional carbon or catalyst source or external hydrocarbon gases. Parametric investigation was performed using different conditions, namely, varying growth temperature from 600 to1000 °C, and growth duration from 5 min to 3 h, as well as using fast quenching or gradual cooling after the thermal treatment, in order to examine the effect on the quality of the produced graphene. The growth took place on silicon wafers and resulted, under optimal conditions, in formation of graphene with 2-3 layers and high graphitic quality, as evidenced by Raman spectroscopy, with characteristic full width at half maximum of the 2D band of 49.46 cm-1, and I2D/IG and ID/IG intensity ratios of 1.15 and 0.26, respectively. Atomic force microscopy and X-ray photoelectron spectroscopy were employed to further evaluate graphene characteristics and enlighten growth mechanism. Electrochemical evaluation of the developed material was performed using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge measurements.

  8. Lapping of chemical vapor deposited diamond films using copper vapor laser

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.J.; Baik, Y.J. [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    1999-04-01

    Laser lapping of diamond films is performed with focused beam of copper vapor laser. Both spherical and rod-shape laser beam are used. Diamond surface is scanned at various scan speeds(0.125, 0.5, 0.75 mm/sec) and beam shifts(5, 10, 20, 40, 100 {mu}m). At 0.125 mm/sec, 10 {mu}m scan condition, the level difference of diamond surface of about 700 {mu}m over 20 mm is reduced to 200 {mu}m. In addition, surface roughness is also improved from 3.53 {mu}m to 2.47 {mu}m at 5 {mu}m beam shift. But, at higher beam shift than 10{mu}m, laser scan makes the surface rougher, which is considered to be due to the non uniform spatial distribution of laser energy. It is concluded that homogenized laser beam with high average power is needed for large area laser lapping of diamond films at appreciable rates. 12 refs., 9 figs.

  9. Growth of Carbon Nanostructure Materials Using Laser Vaporization

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehozeky, S.

    2000-01-01

    Since the potential applications of carbon nanotubes (CNT) was discovered in many fields, such as non-structure electronics, lightweight composite structure, and drug delivery, CNT has been grown by many techniques in which high yield single wall CNT has been produced by physical processes including arc vaporization and laser vaporization. In this presentation, the growth mechanism of the carbon nanostructure materials by laser vaporization is to be discussed. Carbon nanoparticles and nanotubes have been synthesized using pulsed laser vaporization on Si substrates in various temperatures and pressures. Two kinds of targets were used to grow the nanostructure materials. One was a pure graphite target and the other one contained Ni and Co catalysts. The growth temperatures were 600-1000 C and the pressures varied from several torr to 500 torr. Carbon nanoparticles were observed when a graphite target was used, although catalysts were deposited on substrates before growing carbon films. When the target contains catalysts, carbon nanotubes (CNT) are obtained. The CNT were characterized by scanning electron microscopy, x-ray diffraction, optical absorption and transmission, and Raman spectroscopy. The temperature-and pressure-dependencies of carbon nanotubes' growth rate and size were investigated.

  10. A Pattern-based Approach Against Architectural Knowledge Vaporization

    NARCIS (Netherlands)

    Heesch, Uwe van; Avgeriou, Paris

    2009-01-01

    Architectural documentation is often considered as a tedious and resource intensive task, that is usually skipped or performed inadequately. As a result the rationale of the architect’s decisions gets lost. This problem is known as architectural knowledge vaporization. We propose a documentation

  11. Operability test report for the in SITU vapor sampling

    Energy Technology Data Exchange (ETDEWEB)

    Corbett, J.E., Westinghouse Hanford

    1996-05-31

    This report documents the successful completion of testing for the In Situ Vapor Sampling (ISVS) system. The report includes the test procedure (WHC-SD-WM-OTP-196, Rev OA), data sheets, exception resolutions, and a test report summary. This report conforms to the guidelines established in WHC-IP-1026, `Engineering Practice Guidelines,` Appendix L, `Operability Test Procedures and Reports.`

  12. 46 CFR 154.438 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... Independent Tank Type A § 154.438 Design vapor pressure. (a) If the surface of an independent tank type A are mostly flat surfaces,the Po must not exceed 69 kPa gauge (10 psig). (b) If the surfaces of an independent tank type A are formed by bodies of revolution, the design calculation of the Po must be specially...

  13. Vapor phase growth of functional pentacene films at atmospheric pressure

    NARCIS (Netherlands)

    Rolin, C.; Vasseur, K.; Niesen, B.; Willegems, M.; Müller, R.; Steudel, S.; Genoe, J.; Heremans, P.

    2012-01-01

    Compared to traditional vacuum evaporation techniques for small organic molecules, organic vapor phase deposition (OVPD) possesses a extra processing parameter: the pressure of process gas Pch. Here, the influence of large Pch variations (from 0.1 mbar to atmospheric pressure) on pentacene thin film

  14. Mull it over: cannabis vaporizers and harm reduction.

    Science.gov (United States)

    Gartner, Coral E

    2015-11-01

    Legalization of cannabis is likely to lead to greater use. Balanced regulation of potentially less harmful modes of administration, such as vaporizers, is needed. Further research is warranted not only on the direct health effects of vaping cannabis, but also on its potential to decrease co-administration of tobacco with cannabis.

  15. Water vapor pressure versus environmental lapse rate near the tropopause

    Science.gov (United States)

    Ferreira, Antonio; Castanheira, Jose; Gimeno, Luis

    2010-05-01

    The relationship between water vapor pressure and temperature lapse rate in the vicinity of the tropopause was investigated using in situ observations. The water vapor partial pressures and the lapse rates within a vertical distance of ±1.5 km around the first thermal tropopause were calculated from the vertical soundings conducted by the NOAA/CMDL at several locations in the last few decades (GMD Data Archive). A positive non-linear relationship between the two quantities was found to hold across the studied tropopause region at mid-latitudes and polar latitudes. A similar analysis was performed on the 300 and 250 hPa pressure levels (which often intercept the tropopause region), by collecting temperature and humidity observations within 1979-2008 from the Integrated Global Radiosonde Archive (IGRA). A relationship having almost the same shape was detected for statically stable lapse rates at all latitude zones. Given the relevance of water vapor in the radiative transfer in the upper troposphere, the results are an indication of a local influence of water vapor on the thermal structure of the transition layer between the troposphere and stratosphere

  16. Visualization of Atmospheric Water Vapor Data for SAGE

    Science.gov (United States)

    Kung, Mou-Liang; Chu, W. P. (Technical Monitor)

    2000-01-01

    The goal of this project was to develop visualization tools to study the water vapor dynamics using the Stratospheric Aerosol and Gas Experiment 11 (SAGE 11) water vapor data. During the past years, we completed the development of a visualization tool called EZSAGE, and various Gridded Water Vapor plots, tools deployed on the web to provide users with new insight into the water vapor dynamics. Results and experiences from this project, including papers, tutorials and reviews were published on the main Web page. Additional publishing effort has been initiated to package EZSAGE software for CD production and distribution. There have been some major personnel changes since Fall, 1998. Dr. Mou-Liang Kung, a Professor of Computer Science assumed the PI position vacated by Dr. Waldo Rodriguez who was on leave. However, former PI, Dr. Rodriguez continued to serve as a research adviser to this project to assure smooth transition and project completion. Typically in each semester, five student research assistants were hired and trained. Weekly group meetings were held to discuss problems, progress, new research direction, and activity planning. Other small group meetings were also held regularly for different objectives of this project. All student research assistants were required to submit reports for conference submission.

  17. Chemical vapor deposition of fluorine-doped zinc oxide

    Science.gov (United States)

    Gordon, Roy G.; Kramer, Keith; Liang, Haifan

    2000-06-06

    Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

  18. Selective laser vaporization of polypropylene sutures and mesh

    Science.gov (United States)

    Burks, David; Rosenbury, Sarah B.; Kennelly, Michael J.; Fried, Nathaniel M.

    2012-02-01

    Complications from polypropylene mesh after surgery for female stress urinary incontinence (SUI) may require tedious surgical revision and removal of mesh materials with risk of damage to healthy adjacent tissue. This study explores selective laser vaporization of polypropylene suture/mesh materials commonly used in SUI. A compact, 7 Watt, 647-nm, red diode laser was operated with a radiant exposure of 81 J/cm2, pulse duration of 100 ms, and 1.0-mm-diameter laser spot. The 647-nm wavelength was selected because its absorption by water, hemoglobin, and other major tissue chromophores is low, while polypropylene absorption is high. Laser vaporization of ~200-μm-diameter polypropylene suture/mesh strands, in contact with fresh urinary tissue samples, ex vivo, was performed. Non-contact temperature mapping of the suture/mesh samples with a thermal camera was also conducted. Photoselective vaporization of polypropylene suture and mesh using a single laser pulse was achieved with peak temperatures of 180 and 232 °C, respectively. In control (safety) studies, direct laser irradiation of tissue alone resulted in only a 1 °C temperature increase. Selective laser vaporization of polypropylene suture/mesh materials is feasible without significant thermal damage to tissue. This technique may be useful for SUI procedures requiring surgical revision.

  19. Chemical Vapor Deposition of Aluminum Oxide Thin Films

    Science.gov (United States)

    Vohs, Jason K.; Bentz, Amy; Eleamos, Krystal; Poole, John; Fahlman, Bradley D.

    2010-01-01

    Chemical vapor deposition (CVD) is a process routinely used to produce thin films of materials via decomposition of volatile precursor molecules. Unfortunately, the equipment required for a conventional CVD experiment is not practical or affordable for many undergraduate chemistry laboratories, especially at smaller institutions. In an effort to…

  20. Analyzing microporosity with vapor thermogravimetry and gas pycnometry

    NARCIS (Netherlands)

    Dral, A. Petra; ten Elshof, Johan E.

    2018-01-01

    The complementary use of thermogravimetry and pycnometry is demonstrated to expand the toolbox for experimental micropore analysis <1 nm. Thermogravimetry is employed to assess the uptake of water, methanol, ethanol, 1-propanol and cyclohexane vapors in microporous structures at room temperature and