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Sample records for alta tension incorporando

  1. The insulation condition diagnosis of high tension generator stators; Diagnostico del estado de aislamiento de estatores de generadores de alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Robles Pimentel, Edgar Guillermo; Rosales Sedano, Inocente [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    The high tension electrical generators are very high cost equipment, therefore they need to be very reliable. The generators preventive maintenance based in diagnosis techniques of the insulation condition might mean substantial savings for the user. In this article the most common techniques employed all over the world are presented, the greatest part of them already implemented in Mexico by the authors. The techniques and the equipment employed are analyzed and are exemplified with the results obtained in some field experiences. [Espanol] Los generadores electricos de alta tension son equipos de muy alto costo, por lo que necesitan ser muy confiables. El mantenimiento preventivo de los generadores basado en tecnicas de diagnostico del estado del aislamiento puede significar ahorros sustanciales al usuario. En este articulo se presentan las tecnicas mas comunes empleadas en el mundo, la mayor parte de ellas ya implantadas en Mexico por los autores. Se analizan las tecnicas y el equipo empleado, y se ejemplifica con resultados obtenidos de algunas de las experiencias en el campo.

  2. Adaptive coordination of protective relaying in Ehv transmission using artificial intelligence and parallel processing; Esquema adaptativo para la coordinacion de reles de proteccion en redes de transmission de alta tension incorporando tecnicas de inteligencia artificial y procesamiento en paralelo

    Energy Technology Data Exchange (ETDEWEB)

    Orduna, E.; Garces, F; Rivera, J.F. [Univ. Nacional de San Juan, San Juan (Argentina). Instituto de Energia Eletrica; Handschin, E. [Dortmund Univ. (Germany). Lehrstuhl fuer Elektrische Energieversorgung

    1994-12-31

    The protection systems of electric power systems have as function to detect failures as soon possible and isolate the failed component. Considering that the main protection system may fail, protection in the elements adjacent to the failed one must act as a spare, observing an actuation time delay to accomplish selectivity criteria. This work presents the system named CORPRO developed in order to enable the fast determination of adjustments of relays coordination in electric power transmission lines for real time adaptive protection system 9 refs., 8 figs., 4 tabs.

  3. Artificial intelligence tools to support the analysis of the high tension insulator flaming; Herramientas de inteligencia artificial de apoyo al analisis de flameos en aisladores de alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Ortiz, Guillermo; Mejia Lavalle, Manuel; Montoya Tena, Gerardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    Four artificial intelligence tools developed at the Instituto de Investigaciones Electricas (IIE) to support the analysis of high tension insulator flaming are described. The first tool builds up a decision tree departing from historical data, the other 3 tools operate departing from the decision tree previously created to generate production rules, function as an expert system and make tests with many already known cases. These tools could predict the impending occurrence of flaming with enough time allowance for the insulators to be cleaned, since the traditional practice is the periodical cleaning of the insulators and this is not always adequate since the cleaning teams are limited, and the action of the environment is not always constant and for that reason insulators that do not need it are cleaned and vice-versa [Espanol] Se describen 4 herramientas de inteligencia artificial desarrolladas en el Instituto de Investigaciones Electricas (IIE) para apoyar al analisis de flameos en aisladores de alta tension. La primera herramienta construye el arbol de decision a partir de datos historicos; las otras 3 herramientas operan a partir del arbol de decision previamente creado para generar reglas de produccion, funcionar a la manera de un sistema experto y hacer pruebas con muchos casos conocidos. Estas herramientas podrian predecir la ocurrencia inminente del flameo con tiempo suficiente para que los aisladores se limpien, ya que la forma tradicional es limpiar periodicamente los aisladores y esto a veces no es adecuado debido a que las cuadrillas de limpieza son limitadas, ademas de que la accion del medio ambiente no es constante y es por eso que a veces se limpian aisladores que no lo necesitan o viceversa

  4. Diagnosis system for nozzles in high voltage equipment; Sistema de diagnostico para boquillas en equipos de alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Nino, Jose; Escorsa Morales, Oscar [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Lopez Azamar, Ernesto [Comision Federal de Electricidad (Mexico)

    2000-07-01

    The nozzles used in high voltage electrical equipment, such as power transformers and circuit breakers, constitute the elements that present greater fault risk. On the other hand, the faults in the nozzles cause, in most of the cases catastrophic damages, that expose to risk the maintenance personnel of the plant and the peripheral equipment. With the purpose of contributing with on-line monitoring techniques that indicate the nozzles condition and allow to anticipate their possible fault, the Instituto de Investigaciones Electricas (IIE) performed for the laboratory of tests of equipment and materials (LAPEM) of Comision Federal de Electricidad (CFE), a project for the development of a system for the measurement of capacitive currents in these equipments. This system allows to determine the variation in capacitance and dielectric losses, and to determine the presence of internal partial discharges in nozzles of 115, 230 and 400 kV. With this information it is possible to determine the condition of the internal isolation of the nozzles and retire them from service before deterioration takes place that puts in danger the integrity of the equipment. The management of electrical equipment of the Instituto de Investigaciones Electricas developed for LAPEM a system that measures capacitive currents of power transformer nozzles. This system was designed with the purpose of installing it in a transformer of a 400 kV machine, in the fossil power station of Tula, Hidalgo, of the Comision Federal de Electricidad. [Spanish] Las boquillas empleadas en los equipos electricos de alta tension, como transformadores de potencia e interruptores, constituyen los elementos que presentan mayor riesgo de falla. Por otro lado, las fallas en las boquillas provocan en la mayoria de los casos danos catastroficos que ponen en riesgo al personal de mantenimiento de la planta y al equipo periferico. Con la finalidad de aportar tecnicas de monitoreo en linea que indiquen el estado de las

  5. Voltage pre-regulator without insulation with high efficiency; Pre-regulador de tension sin aislamiento con alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Ramos, Octaviano

    2003-04-15

    strokes it is illustrated that the results obtained in the proposed topology are satisfactory because it succeeds in maintaining a high efficiency and a high power factor. [Spanish] Actualmente existe una problematica por el uso inadecuado e ineficiente de la energia electrica en los sistemas de alimentacion, esta problematica se va complicando aun mas con el paso del tiempo, debido a la proliferacion de equipos electronicos que no incorporan alguna solucion para dicha problematica. Esto ha ocasionado una tendencia hacia el desarrollo de sistemas que procesen con mayor eficiencia ({eta}) la energia electrica. Ademas para hacer un buen uso de la energia, se les disena para que puedan corregir el factor de potencia (FP) y por lo tanto reducen la contaminacion de armonicos en la red; los cuales provocan fallas o destruccion en otros equipos electronicos. Adicionalmente se les puede disenar para obtener una buena respuesta dinamica, lo cual asegura que podran contrarrestar eficientemente cambios de carga. La caracteristica no lineal que esta presente en todas las fuentes de alimentacion, que basan su entrada en una etapa de rectificacion y filtrado, provocan un bajo factor de potencia (FP) y una alta distorsion armonica total (THD). El factor es contaminar la red electrica, lo cual puede provocar fallas o descomposturas de otros equipos. Desde hace aproximadamente 15 anos la preocupacion por resolver este problema de uso inadecuado de la energia ha tomado importancia, desarrollando convertidores que corrigen el FP (pre-regulador) y que tradicionalmente se conectan en cascada con la tipica etapa de conversion de corriente directa a corriente directa (CD-CD) usada para regular la tension; esta solucion tiene una baja eficiencia ({eta}) y alto costo, por el exceso de componentes conectados en cascada. Sin embargo la respuesta dinamica (RD) es adecuada ya que se cuenta con etapas separadas para la correccion del FP y la regulacion. A partir de una revision del estado del arte, en

  6. Patella Alta

    OpenAIRE

    Cakmak, Mehmet; Taser, Omer; Karamehmetoglu, Mahmut; Domanic, Unsal

    2004-01-01

    Patella alta is investigated with Insall-Salvati method in lateral X-rays obtained with the knee in 30 flexion in 26 cases with recurrent dislocation of the patella and in 16 cases diagnosed to have chondromalasia. Patella alta is identified in 12 cases with recurrent dislocation of patella and in 9 cases with chondromalasia. Patella alta, which is one of the significaint consative agents of patella femoral instrability, is reviewed under the literature data.

  7. Diagnosis on line and off line of induction motors of low, medium and high voltage; Diagnostico en linea y fuera de linea de motores de induccion de baja, mediana y alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Carvajal, Francisco Antonio; Ramirez, Jose Manuel; Arcos, Luis Fernando [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    The induction motors of low, medium and high voltage are the electrical equipment of greatest application in industry. The importance which they have in the different productive processes does necessary to assure its operative continuity. The anticipated detection of a possible cause of fault allows to plan, with maintenance aims, the programmed removal of the motor. In this article are presented the results of the activities nowadays performed by Management of Electrical Equipment of the Instituto de Investigaciones Electricas (IIE) for the development and application of online diagnosis techniques for induction motors up to 13.8 kV. [Spanish] Los motores de induccion de baja, mediana y alta tension son los equipos eletricos de mayor aplicacion en la industria. La importancia que tienen en los diferentes procesos productivos hace necesario asegurar su continuidad operativa. La deteccion anticipada de una posible causa de falla permite planear, con fines de mantenimiento, la remocion programada del motor. En este articulo se presentan los resultados de las actividades que realiza actualmente la Gerencia de equipos Electricos del Instituto de investigaciones Electricas (IIE) para el desarrollo y la aplicacion de tecnicas de diagnostico en linea para motores de induccion de hasta 13.8 kV.

  8. 75 FR 23263 - Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC...

    Science.gov (United States)

    2010-05-03

    ... Energy Regulatory Commission Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC; Alta Wind VI, LLC; Alta Wind VII, LLC; Alta Wind VIII, LLC; Alta Windpower... Federal Energy Regulatory Commission (Commission), 18 CFR 285.207 (2009), Alta Wind I, LLC, Alta Wind...

  9. 77 FR 29633 - Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC...

    Science.gov (United States)

    2012-05-18

    ..., Alta Wind XII, LLC, Alta Wind XIII, LLC, Alta Wind XIV, LLC, Alta Wind XV, LLC, Alta Windpower... Windpower Development, LLC, and TGP Development Company, LLC (collectively, Petitioners), jointly...

  10. Desarrollo a escala de laboratorio de un antiséptico y cicatrizante para uso veterinario incorporando ingredientes naturales

    OpenAIRE

    Fernández Sierra, Laura; Moreno Gómez, Natacha

    2009-01-01

    Con este proyecto se evalúa la posibilidad de desarrollar un antiséptico y cicatrizante para animales a escala de laboratorio, incorporando miel de abejas y Aloe vera como ingredientes activos del producto -- Los ensayos preliminares consistieron en la evaluación de las formulaciones por medio de pruebas de pre-estabilidad entre los diferentes componentes con el extracto etanólico de la miel a temperatura ambiente, y pruebas de estabilidad de cada tratamiento a 4ºC, 50ºC y temperatura ambient...

  11. Altas capacidades e interdisciplinariedad

    OpenAIRE

    Moreno-García, María José

    2013-01-01

    El presente trabajo fin de grado trata de abordar la importancia de dar una respuesta educativa acorde a las necesidades del alumnado de altas capacidades. Para ello, primeramente, se ha visto necesario definir el término de altas capacidades, analizar sus características, matizar la importancia de su detección temprana, desbancar falsos mitos y conocer la legislación vigente al respecto, para posteriormente elaborar una propuesta de intervención, que se ha llevado a cabo en el Colegio Nelva,...

  12. Surface Tension

    Science.gov (United States)

    Theissen, David B.; Man, Kin F.

    1996-01-01

    The effect of surface tension is observed inmany everyday situations. For example, a slowly leaking faucet drips because the force surface tension allows the water to cling to it until a sufficient mass of water is accumulated to break free.

  13. Estonia's Alta buys Lauma lingerie

    Index Scriptorium Estoniae

    2004-01-01

    Eesti investeeringute firma Alta Capital ostis 76,4 protsenti pesutootja Lauma aktsiatest. Tulevikus plaanitakse suunduda Ida- ja Lääne-Euroopa turgudele. Alta Capital omab 79 protsenti Klementi aktsiatest

  14. Uropatia Obstrutiva Alta

    OpenAIRE

    Campos Pinheiro, L; Matos Ferreira, A

    1999-01-01

    As lesões obstrutivas do aparelho urinário são muito frequentes. Apresenta-se uma revisão da etiologia e fisiopatologia da uropatia obstrutiva alta. Descreve-se pormenorizadamente a sua clínica e diagnóstico realçando-se os exames complementares mais adequados. Por fim apresentam-se as orientações terapêuticas e o prognóstico das diversas situações englobadas neste capítulo.

  15. de alta frecuencia

    Directory of Open Access Journals (Sweden)

    Juan Carlos Gáquez Abab

    2007-01-01

    Full Text Available Los mercados de consumo de alta frecuencia presentan rasgos particulares en cuanto a la diversidad de estrategias de precio, constantes promociones en precio, publicidad masiva o estrategias de marca que hacen que la identificación de segmentos sea especialmente interesante para la empresa. En el presente trabajo se lleva a cabo un análisis de segmentación sobre datos de panel que pretende identificar cuántos segmentos existen y describir cuál es su comportamiento en relación a variables como el precio o las promociones de ventas.

  16. Proyecto PRACTICE: Evaluación de alternativas de gestión frente a la desertificación incorporando la participación y experiencias locales

    NARCIS (Netherlands)

    Llovet López, J.; Alloza, J.A.; Bautista, S.; Guixot, L.; Mayor, A.G.; Murias, C.; Vilagrosa, A.; Rámon Vallejo, V.

    2013-01-01

    El proyecto PRACTICE (Prevention and Restoration Actions to Combat Desertification. An Integrated Assessment) del 7º programa marco de la Comisión Europea, ha desarrollado metodologías para la evaluación de alternativas de gestión destinadas a la lucha contra la desertificación, incorporando el cono

  17. Servidores web de altas prestaciones

    OpenAIRE

    Castillo Valdivieso, Pedro; Bernier Villamor, Jos?? Luis; Mora Garc??a, Antonio Miguel; Garc??a-S??nchez, Pablo; Garc??a Arenas, Mar??a Isabel

    2013-01-01

    Para crear un sitio web exitoso debemos ser cuidadosos con muchos detalles, ya que la arquitectura, la selecci??n del hardware, o la implementaci??n de las aplicaciones afectar??n al rendimiento del sistema completo. Es m??s, un sitio que no est?? preparado para dar servicio a un n??mero creciente de clientes o usuarios, a la larga puede llevar al fracaso a la empresa. En este trabajo, se presenta una visi??n general de la nueva asignatura Servidores Web de Altas Prestaciones, del nuevo plan...

  18. TransAlta: More than a utility

    International Nuclear Information System (INIS)

    TransAlta Utilities Corporation is Canada's largest privately owned utility and is also a major coal mining company. In 1989, TransAlta produced 20.9% of all coal mined in Canada. A brief history of TransAlta is presented along with TransAlta's present coal operations and plans for the next three years. An overview is presented of how TransAlta Fuel Supply is organized to utilize contracted mining operation, engineering and environmental services and in-house capabilities. Recent strategic initiatives to improve organizational efficiency and the mining operations are discussed. These range from developing a common departmental vision to modifying major mining equipment. TransAlta's proactive role in clean coal combustion such as low NOx-SOx burner, integrated combined cycle gasification, and other energy research projects is reviewed. A summary is provided of recent participation of TransAlta in environmental management initiatives. Recent successes of TransAlta's unregulated subsidiary in the development of cogeneration facilities and the future of this area of business are discussed. 8 refs., 4 figs

  19. Alta peab tasuma Kalevile mais / Kersti Saar

    Index Scriptorium Estoniae

    Saar, Kersti

    2008-01-01

    Indrek Rahumaa juhitav Alta Capital peab tasuma Oliver Kruudale Kalevi tütarfirmade eest 660 miljonit krooni hiljemalt 30. maiks. Vt. samas: Investorid teavad tehingu hinda ja lõplikku tähtaega. Diagramm: Kalevi turuväärtus jääb Alta müügihinnale alla

  20. Skin tension related to tension reduction sutures.

    Science.gov (United States)

    Hwang, Kun; Kim, Han Joon; Kim, Kyung Yong; Han, Seung Ho; Hwang, Se Jin

    2015-01-01

    The aim of this study was to compare the skin tension of several fascial/subcutaneous tensile reduction sutures. Six upper limbs and 8 lower limbs of 4 fresh cadavers were used. At the deltoid area (10 cm below the palpable acromion) and lateral thigh (midpoint from the palpable greater trochanter to the lateral border of the patella), and within a 3 × 6-cm fusiform area of skin, subcutaneous tissue defects were created. At the midpoint of the defect, a no. 5 silk suture was passed through the dermis at a 5-mm margin of the defect, and the defect was approximated. The initial tension to approximate the margins was measured using a tensiometer.The tension needed to approximate skin without any tension reduction suture (S) was 6.5 ± 4.6 N (Newton). The tensions needed to approximate superficial fascia (SF) and deep fascia (DF) were 7.8 ± 3.4 N and 10.3 ± 5.1 N, respectively. The tension needed to approximate the skin after approximating the SF was 4.1 ± 3.4 N. The tension needed to approximate the skin after approximating the DF was 4.9 ± 4.0 N. The tension reduction effect of approximating the SF was 38.8 ± 16.4% (2.4 ± 1.5 N, P = 0.000 [ANOVA, Scheffé]). The tension reduction effect of approximating the DF was 25.2% ± 21.9% (1.5 ± 1.4 N, P = 0.001 [ANOVA, Scheffé]). The reason for this is thought to be that the SF is located closely to the skin unlike the DF. The results of this study might be a basis for tension reduction sutures.

  1. Skin tension related to tension reduction sutures.

    Science.gov (United States)

    Hwang, Kun; Kim, Han Joon; Kim, Kyung Yong; Han, Seung Ho; Hwang, Se Jin

    2015-01-01

    The aim of this study was to compare the skin tension of several fascial/subcutaneous tensile reduction sutures. Six upper limbs and 8 lower limbs of 4 fresh cadavers were used. At the deltoid area (10 cm below the palpable acromion) and lateral thigh (midpoint from the palpable greater trochanter to the lateral border of the patella), and within a 3 × 6-cm fusiform area of skin, subcutaneous tissue defects were created. At the midpoint of the defect, a no. 5 silk suture was passed through the dermis at a 5-mm margin of the defect, and the defect was approximated. The initial tension to approximate the margins was measured using a tensiometer.The tension needed to approximate skin without any tension reduction suture (S) was 6.5 ± 4.6 N (Newton). The tensions needed to approximate superficial fascia (SF) and deep fascia (DF) were 7.8 ± 3.4 N and 10.3 ± 5.1 N, respectively. The tension needed to approximate the skin after approximating the SF was 4.1 ± 3.4 N. The tension needed to approximate the skin after approximating the DF was 4.9 ± 4.0 N. The tension reduction effect of approximating the SF was 38.8 ± 16.4% (2.4 ± 1.5 N, P = 0.000 [ANOVA, Scheffé]). The tension reduction effect of approximating the DF was 25.2% ± 21.9% (1.5 ± 1.4 N, P = 0.001 [ANOVA, Scheffé]). The reason for this is thought to be that the SF is located closely to the skin unlike the DF. The results of this study might be a basis for tension reduction sutures. PMID:25569413

  2. Demonstration of Surface Tension.

    Science.gov (United States)

    Rosenthal, Andrew J.

    2001-01-01

    Surface tension is a fundamental obstacle in the spontaneous formation of bubbles, droplets, and crystal nuclei in liquids. Describes a simple overhead projector demonstration that illustrates the power of surface tension that can prevent so many industrial processes. (ASK)

  3. A high sensibility technique to detect the incipient defects in high tension bushings; Una tecnica de alta sensibilidad para detectar defectos incipientes en boquillas de alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Robles Pimentel, Edgar; Mestizo Rivera, Antolin; Romero Camberos, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    In this article a testing technique to locate incipient faults in transformer bushings is reported, specifically the one related to the internal disconnection of the capacitive tap, which is exemplified with a device having a problem of this kind. [Espanol] En el presente articulo se reporta una tecnica de prueba para localizar fallas incipientes en las boquillas de los transformadores, especificamente la relacionada con la desconexion interna del tap capacitivo, lo cual se ejemplifica con un dispositivo que padece un problema de ese tipo.

  4. Carriles para alta velocidad. Comportamiento en fatiga

    Directory of Open Access Journals (Sweden)

    Duart, J. M.

    2005-02-01

    -aire inducido. Los ensayos de fatiga de los carriles soldados se llevan a cabo por flexión en cuatro puntos en concordancia con la norma europea. El método Locati, descrito en esta nota, está basado en la Ley de Miner de daño acumulado y en las curvas de Wohler del material ensayado. Permite calcular, con precisión suficiente, las tensiones límites de fatiga al 50%. Así, los valores obtenidos, en ensayos a dos millones de ciclos, para carriles sin soldar (Sf = 353 MPa, carriles soldados con precalentamiento de oxipropano (Sf = 225 MPa y carriles soldados con precalentamiento de propano-aire inducido (Sf = 210 MPa son muy similares y aceptables a los estipulados por los métodos de determinación del límite de fatiga según norma europea. Debido a la comodidad, rapidez y bajo coste del método Locati resulta, en nuestra opinión, muy adecuado para el control de calidad de los procesos de soldadura aluminotérmica en vigor, de carriles de alta resistencia.

  5. Tension chylothorax following pneumonectomy

    Directory of Open Access Journals (Sweden)

    Hemang Yadav

    2015-01-01

    Full Text Available Post-pneumonectomy chylothorax is an uncommon complication following surgery, with an estimated incidence of less than 0.7%. Post-pneumonectomy tension chylothorax, where rapid accumulation of chyle in the post-pneumonectomy space results in hemodynamic compromise, is exceedingly rare, with just 7 cases previously reported. All prior cases of tension chylothorax were managed operatively with decompressive chest tube placement followed by open thoracic duct repair. Our case is the first reported tension chylothorax to be managed conservatively by thoracostomy drainage coupled with a period of parenteral nutrition followed by a medium chain triglyceride-restricted diet.

  6. Tunneling with negative tension

    CERN Document Server

    Marvel, Kate

    2008-01-01

    We describe a new family of thin-wall instantons, with negative tension bubble walls, that mediate tunneling between Minkowski or de Sitter vacua. Some of these instantons can have exponentially enhanced tunneling rates, and would dominate the Euclidean path integral, representing a severe non-perturbative instability in any theory which supports them. We give two constructions of these instantons in theories which are perturbatively stable, but violate the null energy condition. One construction uses a scalar field theory with higher-derivative kinetic term, and is similar to the Coleman-de Luccia positive tension instanton. The other construction employs a negative-tension boundary arising from Z_2 orbifolding: it resembles a "bubble of nothing" which nucleates and grows, consuming the surrounding de Sitter or Minkowski spacetime. We explain how the spectral flow for fluctutations about the thin-wall tunneling solutions automatically protects causality, for both positive and negative tension instantons. We ...

  7. Alta Capital investeerib miljardeid kroone / Raigo Neudorf

    Index Scriptorium Estoniae

    Neudorf, Raigo

    2006-01-01

    Investeerimisfirma Alta Capital nõukogu esimees Indrek Rahumaa annab ülevaate sellest, kuidas ettevõte on lühikese ajaga suutnud omandada osaluse mitmetes ettevõtetes ning suunanud neisse investeeringuid 150 miljoni euro väärtuses. Vt. samas: Osalused; Omanikud

  8. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    la Cour, M; Kiilgaard, Jens Folke; Eysteinsson, T;

    2000-01-01

    To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide.......To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide....

  9. Estudio del comportamiento en flexocompresión de los hormigones de alta resistencia

    OpenAIRE

    Arenas de Pablo, Juan José; Gutiérrez Martín, Germán; Vicente Cabrera, Miguel Ángel; González Cabrera, Dorys Carmen

    2004-01-01

    RESUMEN. Este artículo describe la máquina de ensayo desarrollada en el Laboratorio de Estructuras de la Universidad de Cantabria para obtener experimentalmente la distribución de tensiones en hormigones de diferentes resistencias, desde hormigones convencionales hasta hormigones de alta resistencia. Utilizando la máquina de ensayo anteriormente mencionada han sido ensayadas 240 probetas bajo carga creciente y excéntrica hasta rotura. Las variables de ensayo han sido la forma de la probeta, e...

  10. Magnetic tension in cosmology

    CERN Document Server

    Tsagas, C G

    2001-01-01

    The vector nature of magnetic fields and the general relativistic geometrical interpretation of gravity lead to a unique coupling between magnetism and spacetime curvature, by effectively transferring the field properties into the spacetime itself. The key magnetic property appears to be the tension of the field lines. Combined with geometry, the magnetic tension triggers a range of rather unexpected effects with profound implications. The field suppresses or boosts density fluctuations depending on the strength of the curvature deformation. It can act as an effective cosmological constant or mimic a time-decaying quintessence. Moreover, even weak magnetic fields become key players when the curvature is strong. For instance, a seed field could halt the accelerated phase in certain inflationary models. The magnetic tension also damps gravity waves and shows an intriguing tendency to smooth out spatial curvature distortions. We describe the nature and the range of these effects and discuss their potential impli...

  11. Diffusione molecolare neLl' alta atmosfera

    Directory of Open Access Journals (Sweden)

    C. ARDUINI

    1963-06-01

    Full Text Available Le perturbazioni indotte nell'alta atmosfera dall'emissione,
    a mezzo di razzi sonda, di nubi di vapori estranei sono un utile
    mezzo per lo studio simultaneo di alcune caratteristiche fisiche e dinamiche
    degli alti strati.
    La presente relazione illustra in breve i principi di alcune tecniche
    per la misura del coefficiente di diffusione binaria tra l'aria e il vapore
    della nube artificiale.

  12. TransAlta 2003 annual report

    International Nuclear Information System (INIS)

    This annual report presents financial information from TransAlta Corp., along with a review of its operations throughout 2003 and a summary of the how the electric utility has performed in terms of power generation, independent power producers, transmission and energy marketing. TransAlta is one of the largest non-regulated power generation and wholesale marketing companies in Canada. It's assets include coal-fired, gas-fired, hydro and renewable generation facilities in Canada, the United States, Mexico and Australia. Reported earnings in 2003 were $1.26 per share compared to $1.17 in 2002. The strong first quarter was followed by harsh market conditions, low water levels which affected hydro production, and pricing restrictions in Ontario that reduced contribution from the Sarnia plant. This report outlines the utility's progress in increasing revenue and producing more power. In 2003, unplanned outages were reduced by 7 per cent and injury frequency rate was reduced by 27 per cent. The installation of 114 wind turbines in Fort Macleod, Alberta, increased TransAlta's renewable energy capacity to 3.7 per cent in 2003. The wind farm produces 75 MW of electricity, enough to power more than 32,500 homes annually. This report summarized the company's energy resource activities and presented an operations review as well as consolidated financial statements and common share information. This included the utility's assets, liabilities, revenues, expenses and cash flows. Revenue and expenditure statements were summarized by source. refs., tabs., figs

  13. Rein tension during canter

    NARCIS (Netherlands)

    Egenvall, Agneta; Eisersiö, Marie; Rhodin, Marie; van Weeren, P.R.; Roepstorff, Lars

    2015-01-01

    Riders generally use reins as a means for communication with the horse. At present, the signalling pattern is poorly understood. The aim of this study was to illustrate and analyse the rein tension patterns in a number of rider/horse combinations across a variety of exercises in the canter gait. Our

  14. The Tension Literature.

    Science.gov (United States)

    Frederick, A. B.

    This is a bibliography of literature on the subject of tension. Books, films, and periodicals with a bearing on stress, relaxation, anxiety, and/or methods of controlling stress are listed from the fields of physiology, psychology, and philosophy. New methods such as transcendental meditation and biofeedback are analyzed briefly and criteria are…

  15. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T;

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta...

  16. Social and environmental tensions

    DEFF Research Database (Denmark)

    Saito, Moeko; Rutt, Rebecca Leigh; Chhetri, Bir Bahadur Khanal

    2014-01-01

    to forests. Our case highlights the risk that the mere application of affirmative measures may give rise to difficult social and environmental tensions. Thus, this paper calls for such measures to effectively incorporate local perspectives in their designs and to be reflective, by allowing for regular...

  17. Surface tension of spherical drops from surface of tension

    International Nuclear Information System (INIS)

    The determination of surface tension of curved interfaces is a topic that raised many controversies during the last century. Explicit liquid-vapor interface modelling (ELVI) was unable up to now to reproduce interfacial behaviors in drops due to ambiguities in the mechanical definition of the surface tension. In this work, we propose a thermodynamic approach based on the location of surface of tension and its use in the Laplace equation to extract the surface tension of spherical interfaces from ELVI modelling

  18. Surface tension of spherical drops from surface of tension

    Energy Technology Data Exchange (ETDEWEB)

    Homman, A.-A.; Bourasseau, E. [CEA/DAM DIF, F-91297 Arpajon Cedex (France); Stoltz, G. [Université Paris-Est, CERMICS (ENPC), INRIA, F-77455 Marne-la-Vallée (France); Malfreyt, P. [Institut de Chimie de Clermont-Ferrand, Université Blaise Pascal, UMR CNRS 6296, ICCF, BP 10448, F-63000 Clermont-Ferrand (France); Strafella, L.; Ghoufi, A., E-mail: aziz.ghoufi@univ-rennes1.fr [Institut de Physique de Rennes, Université de Rennes 1 UMR 6251 CNRS, 263 avenue Général Leclerc, 35042 Rennes (France)

    2014-01-21

    The determination of surface tension of curved interfaces is a topic that raised many controversies during the last century. Explicit liquid-vapor interface modelling (ELVI) was unable up to now to reproduce interfacial behaviors in drops due to ambiguities in the mechanical definition of the surface tension. In this work, we propose a thermodynamic approach based on the location of surface of tension and its use in the Laplace equation to extract the surface tension of spherical interfaces from ELVI modelling.

  19. Surface Tension and Capillary Rise

    Science.gov (United States)

    Walton, Alan J.

    1972-01-01

    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  20. Aprendizaje cooperativo con alumnos de altas capacidades

    OpenAIRE

    Herrera Lara, Inmaculada

    2016-01-01

    El presente Trabajo Fin de Grado tiene como finalidad conocer e investigar la intervención educativa que se lleva a cabo con los alumnos de altas capacidades a través del aprendizaje cooperativo. Estos alumnos necesitan de la ayuda y colaboración de los otros para lograr verdaderos procesos de aprendizaje. Sin la colaboración de docentes, padres y demás organismos del centro educativo no sería posible ofrecer una respuesta válida y eficaz a las necesidades que presenta este colectivo. Tal com...

  1. Gramicidin channel kinetics under tension.

    OpenAIRE

    Goulian, M; Mesquita, O. N.; Fygenson, D K; Nielsen, C; Andersen, O S; Libchaber, A.

    1998-01-01

    We have measured the effect of tension on dimerization kinetics of the channel-forming peptide gramicidin A. By aspirating large unilamellar vesicles into a micropipette electrode, we are able to simultaneously monitor membrane tension and electrical activity. We find that the dimer formation rate increases by a factor of 5 as tension ranges from 0 to 4 dyn/cm. The dimer lifetime also increases with tension. This behavior is well described by a phenomenological model of membrane elasticity in...

  2. Surface tension and microgravity

    International Nuclear Information System (INIS)

    The behaviour of confined liquids on board an orbiting spacecraft is mainly driven by surface tension phenomena, which cause an apparently anomalous response of the liquid when compared with the behaviour that can be observed on an Earth laboratory provided that the amount of liquid is high enough. The reason is that in an orbiting spacecraft the different inertial forces acting on the bulk of the liquid are almost zero, causing thus capillary forces to be the dominant ones. Of course, since gravity forces are proportional to the liquid volume, whereas surface tension forces are proportional to the liquid surface, there are situations on Earth where capillarity can be the dominant effect, as it happens when very small volume liquid samples are considered. However, work with small size samples may require the use of sophisticated optical devices. Leaving aside the neutral buoyancy technique, a way of handling large liquid interfaces is by using drop towers, where the sample falls subjected to the action of Earth’s gravity. This approach is suitable when the characteristic time of the problem under consideration is much smaller than the drop time. In this work the transformation of an out-of-use chimney into a drop tower is presented. Because of the miniaturization, hardiness and low cost of current electronic devices, a drop tower can be used as an inexpensive tool for undergraduate students to experimentally analyse a large variety of surface tension driven phenomena. (paper)

  3. Longwall AFC chain tension measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lugg, P.; Guan, Z.; Pienaar, B.

    2009-10-01

    CRC Mining has developed a chain tension meter to measure the AFC chain tension during the operation. The device was certified Ex ia IP55 by SIMTARS for use in hazardous areas. In June 2007 this device was successfully trialled in an Australian longwall face. The trial was run monitoring AFC chain tensions over a few shifts. The dynamic behaviour and unequal sharing of load between the chains were recorded and found to be significant. During this trial the robustness of the tension meter electronics and protection housing was demonstrated, the measurement of AFC chain tensions on a working face can be achieved reliably. 2 refs., 14 figs.

  4. Rainbow surface tension analysis.

    Science.gov (United States)

    Adler, Charles L; Smith, Valen A; Haddad, Natalie M

    2008-03-31

    In this paper we outline a new all-optical non-contact technique for measurement of the surface tension of a Newtonian fluid. It is based on the accurate measurement of the spacing of the supernumerary fringes produced by the diffraction pattern of a laser beam transmitted through or reflected by a thin vertically-draining film of the liquid. We discuss the basic theory and application of this technique, and several issues which must be addressed before it can be used commercially. PMID:18542611

  5. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1992-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  6. World Wide Web Search Engines: AltaVista and Yahoo.

    Science.gov (United States)

    Machovec, George S., Ed.

    1996-01-01

    Examines the history, structure, and search capabilities of Internet search tools AltaVista and Yahoo. AltaVista provides relevance-ranked feedback on full-text searches. Yahoo indexes Web "citations" only but does organize information hierarchically into predefined categories. Yahoo has recently become a publicly held company and currently…

  7. Fragmentation in Biaxial Tension

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, G H; Archbold, G C; Hurricane, O A; Miller, P L

    2006-06-13

    We have carried out an experiment that places a ductile stainless steel in a state of biaxial tension at a high rate of strain. The loading of the ductile metal spherical cap is performed by the detonation of a high explosive layer with a conforming geometry to expand the metal radially outwards. Simulations of the loading and expansion of the metal predict strain rates that compare well with experimental observations. A high percentage of the HE loaded material was recovered through a soft capture process and characterization of the recovered fragments provided high quality data, including uniform strain prior to failure and fragment size. These data were used with a modified fragmentation model to determine a fragmentation energy.

  8. Research on Web Press Tension Control System

    OpenAIRE

    Chen Sheng Jiang; Zhang Chun Feng; Wang Zhong You; Li Qing Lin

    2016-01-01

    Tension control of press is a key and difficult point of the whole machine control. The stand or fall of tension is directly related to the quality of the products. According to the characteristics of the web press tension control, this paper expounds the main factors influencing tension and the purpose of tension control, researches on the tension control principle of web tape, analyzes control rule and control circuit of tension control system, illustrates the advantages of PID control law ...

  9. Nonequilibrium interfacial tension during relaxation.

    Science.gov (United States)

    Bier, Markus

    2015-10-01

    The concept of a nonequilibrium interfacial tension, defined via the work required to deform a system such that the interfacial area is changed while the volume is conserved, is investigated theoretically in the context of the relaxation of an initial perturbation of a colloidal fluid towards the equilibrium state. The corresponding general formalism is derived for systems with planar symmetry and applied to fluid models of colloidal suspensions and polymer solutions. It is shown that the nonequilibrium interfacial tension is not necessarily positive, that negative nonequilibrium interfacial tensions are consistent with strictly positive equilibrium interfacial tensions, and that the sign of the interfacial tension can influence the morphology of density perturbations during relaxation. PMID:26565189

  10. Research on Web Press Tension Control System

    Directory of Open Access Journals (Sweden)

    Chen Sheng Jiang

    2016-01-01

    Full Text Available Tension control of press is a key and difficult point of the whole machine control. The stand or fall of tension is directly related to the quality of the products. According to the characteristics of the web press tension control, this paper expounds the main factors influencing tension and the purpose of tension control, researches on the tension control principle of web tape, analyzes control rule and control circuit of tension control system, illustrates the advantages of PID control law adopted in the tension control system, and concludes the influencing factors of paper tape tension control system and the corresponding problems needed to solve in the control.

  11. Alta Capital venitab Kruudale tasumisega / Sten-Aleks Pihlak

    Index Scriptorium Estoniae

    Pihlak, Sten-Aleks

    2008-01-01

    Alta Capital Partnersid pole veel maksnud Oliver Kruudale 2007. aasta septembris müüdud Tere ja Kalevi eest. Vt. samas: Rahasaamise venimine on lükanud Kalevi viimastel kuudel laenurallile. Kommenteerib Aivar Häelm

  12. Handling device for stud tensioner

    International Nuclear Information System (INIS)

    The handling device for a stud tensioner machine used by example for fixing the reactor vessel head has an extension module, joining elements and means for displacement in vertical and horizontal axis

  13. Horizon Thermodynamics and Gravitational Tension

    CERN Document Server

    Widom, A; Srivastava, Y N

    2016-01-01

    We consider the thermodynamics of a horizon surface from the viewpoint of the vacuum tension $\\tau =(c^4/4G )$. Numerically, $\\tau \\approx 3.026\\times 10^{43}$ Newton. In order of magnitude, this is the tension that has been proposed for microscopic string models of gravity. However, after decades of hard work on string theory models of gravity, there is no firm scientific evidence that such models of gravity apply empirically. Our purpose is thereby to discuss the gravitational tension in terms of the conventional Einstein general theory of relativity that apparently does explain much and maybe all of presently known experimental gravity data. The central result is that matter on the horizon surface is bound by the entropy-area law by tension in the closely analogous sense that the Wilson action-area law also describes a surface confinement.

  14. O papel do professor junto ao aluno com Altas Habilidades

    Directory of Open Access Journals (Sweden)

    Andréia Jaqueline Devalle Rech

    2012-03-01

    Full Text Available .Quando se discute a Educação Especial é comum, num primeiro momento, lembrar do aluno que compõe o especial na Educação como aquele com deficiência mental, auditiva, visual ou física. No entanto, assim como essas crianças, também os alunos com altas habilidades necessitam de um atendimento especializado, pois ele também é um sujeito da Educação Especial. Nesse sentido, este artigo apresenta a definição de altas habilidades, baseada na teoria de um pesquisador norte-americano e, como foco principal algumas questões que envolvem o professor de forma mais direta com o aluno com altas habilidades em sala de aula. Entre elas estão: questões sobre a aprendizagem escolar desses alunos, bem como os fatores que fazem parte desse processo, estratégias de ensino e a importância da identificação dos alunos com altas habilidades.Palavras-chave: Educação Especial. Professor. Aluno com Altas Habilidades

  15. Tension leg platform project execution

    Institute of Scientific and Technical Information of China (English)

    Zhang Dagang; Wang Chunsheng; Zhang Tianyu

    2013-01-01

    The first floating platform concept design work for South China Sea is undergoing in DMAR' s office now.This tension leg platform has potential to become the first advanced floating production platform project.Project execution is always a challenge for floating system.This paper focuses on the critical elements of project execution for tension leg platform,and studies potential implications to future oil and gas exploration in South China Sea.There are many factors affecting successful execution of floating system project,including technical issues,engineering management,interface management,etc.There are also failure examples of project execution in the industry.The author has participated 28 large detailed projects and has gained extensive experience on floating projects,with ample hands-on project experiences.A detailed tension leg platform project study example and discussions in depth are presented for future project execution in China deepwater development.

  16. High intensity Discharge lighting; Alumbrado de alta intensidad de descarga

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza E, Ernesto J. [Manufacturera de Reactores, S. A., Mexico, D. F. (Mexico)

    1993-12-31

    This paper gets into contact with some fundamentals in the operation of high discharge intensity lamps. There are useful definitions, as well as the study of the operation of high pressure sodium lamps and of metallic additives operating at less than nominal power. [Espanol] Este trabajo pone al lector en contacto con algunos fundamentos de la operacion de las lamparas de alta intensidad de descarga (HID). Se encuentra con definiciones utiles, asi como el estudio de la operacion de las lamparas de sodio en alta presion y de aditivos metalicos operando a una potencia menor que la nominal.

  17. Cócs. Hallmark of the Terra Alta

    OpenAIRE

    Maria Del Loreto Meix

    2004-01-01

    This article looks at the traditional cake making in the Terra Alta (Catalonien) area linked to festivities, and in particular the pastries usually made. In this area the pastries are known as cócs, a word common to Terra Alta and the neighbouring districts of Ribera d'Ebre and the Priorat. Locally produced mistelle, sweet or rancid wine is served with the pastries. Nowadays, the bakeries and cake makers in the area's towns and villages also produce traditionally crafted products, tha...

  18. Enriquecimiento curricular para el alumnado con altas capacidades en primaria

    OpenAIRE

    Boldú Caballero, Tomás

    2013-01-01

    La finalidad de este documento es proporcionar al lector, primero, una rápida ojeada a la trayectoria histórica de la atención a las NEE (más concretamente de las altas capacidades); segundo, una conceptualización de las altas capacidades y sus necesidades educativas específicas tomando como punto de referencia algunos de lo más eminentes autores y corrientes psicopedagógicas actuales o del pasado reciente; y por último, facilitar ejemplos prácticos desde la perspectiva del doc...

  19. Apparatus for determining surface tension

    Science.gov (United States)

    Razouk, R. E.

    1978-01-01

    System for studying capillary action uses pressure transducer and chart recorder instead of manometer. Apparatus enables measurements to be made under controlled atmospheres. It also may be remotely operated. These features are particularly useful when dealing with noxious liquids and for study of surface tension under high-pressure conditions that require use of all-metal apparatus.

  20. Características del alumnado con altas capcidades

    OpenAIRE

    Grau Rubio, Claudia

    2012-01-01

    Se describen las características del alumnado con altas capacidades, la terminología más usual y la clasificación. Asimismo, se expone la teoría de la disincronía y los mitos relacionados con este alumnado.

  1. Investigación en materiales sometidos a altas presiones

    Directory of Open Access Journals (Sweden)

    Juan Carlos Fallas

    2010-10-01

    Full Text Available El estudio de materiales sometidos a altas presiones es un tema de profundo interés en el campo científico e ingenieril actual. Diferentes análisis experimentales permiten descubrir los efectos que esta condición genera en la estructura molecular de un determinado compuesto.La implementación de la celda de diamante para altas presiones ha revolucionado este tema en las últimas décadas, al ser una herramienta vital en el desarrollo de estas pruebas. Presiones superiores, inclusive a los 20 Gpa, pueden ser generadas con este artefacto.Adicionalmente, la posibilidad de caracterizar muestras bajo estos parámetros y la inclusión de otras variables, como altas temperaturas, ofrecen un ambiente propicio para la evaluación de materiales bajo condiciones extremas.Este artículo explica los fundamentos básicos de la ciencia de materiales a altas presiones. Aspectos relevantes acerca de la celda de diamante y de la ejecución de experimentos son tratados en diferentes apartados. Se quiere compartir los alcances que esta disciplina posee, así como diferentes resultados que se han logrado en varias aplicaciones.Investigaciones en materiales para el almacenamiento de hidrógeno y energía, así como la simulación de condiciones presentes a muy altas profundidades en la Tierra, son casos que se tomaron en cuenta para ejemplificar áreas donde existen aplicaciones sustanciales.

  2. Normal-tension glaucoma (Low-tension glaucoma)

    OpenAIRE

    Anderson Douglas

    2011-01-01

    Glaucoma is now considered an abnormal physiology in the optic nerve head that interacts with the level of intraocular pressure (IOP), with the degree and rate of damage depending on the IOP and presumably the degree of abnormal physiology. Diagnosis of normal-tension glaucoma (NTG), defined as glaucoma without a clearly abnormal IOP, depends on recognizing symptoms and signs associated with optic nerve vulnerability, in addition to absence of other explanations for disc abnormality and visua...

  3. Light Scattering by Surface Tension Waves.

    Science.gov (United States)

    Weisbuch, G.; Garbay, F.

    1979-01-01

    This simple and inexpensive experiment is an illustration of the physical concepts of interaction between light and surface tension waves, and provides a new method of measuring surface tension. (Author/GA)

  4. Fluoride glass: Crystallization, surface tension

    Science.gov (United States)

    Doremus, R. H.

    1988-01-01

    Fluoride glass was levitated acoustically in the ACES apparatus on STS-11, and the recovered sample had a different microstructure from samples cooled in a container. Further experiments on levitated samples of fluoride glass are proposed. These include nucleation, crystallization, melting observations, measurement of surface tension of molten glass, and observation of bubbles in the glass. Ground experiments are required on sample preparation, outgassing, and surface reactions. The results should help in the development and evaluation of containerless processing, especially of glass, in the development of a contaminent-free method of measuring surface tensions of melts, in extending knowledge of gas and bubble behavior in fluoride glasses, and in increasing insight into the processing and properties of fluoride glasses.

  5. Surface Tension Confines Cryogenic Liquid

    Science.gov (United States)

    Castles, Stephen H.; Schein, Michael E.

    1989-01-01

    New type of Dewar provides passive, constant-temperature cryogenic cooling for scientific instruments under normal-to low-gravity conditions. Known as Surface-Tension-Contained Liquid Cryogen Cooler (STCLCC), keeps liquid cryogen in known location inside the Dewar by trapping liquid inside spongelike material. Unique sponge material fills most of volume of inner tank. Sponge is all-silica, open-cell material similar to that used for Space Shuttle thermal-protection tiles.

  6. Robust Tensioned Kevlar Suspension Design

    Science.gov (United States)

    Young, Joseph B.; Naylor, Bret J.; Holmes, Warren A.

    2012-01-01

    One common but challenging problem in cryogenic engineering is to produce a mount that has excellent thermal isolation but is also rigid. Such mounts can be achieved by suspending the load from a network of fibers or strings held in tension. Kevlar fibers are often used for this purpose owing to their high strength and low thermal conductivity. A suite of compact design elements has been developed to improve the reliability of suspension systems made of Kevlar.

  7. Application of stud loading tension technology

    International Nuclear Information System (INIS)

    The author principally describes a new way to pretension studs of large diameters--stud loading tension technology, and discusses the rationale of the technology, the calculating method of tension amount, the step and the calibrating method to tension studs. The technology makes little damage on equipment, has seal assemblies uniformly forced and greatly increases the reliability of container seals

  8. Professional Identity Tensions of Beginning Teachers

    Science.gov (United States)

    Pillen, Marieke; Beijaard, Douwe; den Brok, Perry

    2013-01-01

    This study reports on interviews with 24 beginning teachers about tensions they experienced regarding their professional identity. The interviewees reported a total of 59 tensions of tension that fell into three themes: (1) the change in role from student to teacher; (2) conflicts between desired and actual support given to students; and (3)…

  9. Transcutaneous oxygen tension in imminent foot gangrene

    DEFF Research Database (Denmark)

    Tønnesen, K H

    1978-01-01

    with moderate obstruction, the oxygen tension reached zero at a toe systolic blood pressure of 5--10 mmHg (tilt toe up) and reached arterial oxygen tension at about 50 to 70 mmHg (tilt toe down). In legs withsevere arterial obstruction and ischaemic rest pain, oxygen tension rose from zero not before systolic...

  10. Alta Velocità e innovazioni tecnologiche e funzionali

    Directory of Open Access Journals (Sweden)

    Emilia Giovanna Trifiletti

    2008-05-01

    Full Text Available La realizzazione di linee e di stazioni dell’Alta Velocità, oltre ad influire sullo sviluppo urbanistico delle aree interessate, sta cambiando radicalmente le relazioni spazio-temporali fra i diversi centri urbani connessi dalla rete del trasporto su ferro. Da un lato sono mutate le funzioni assunte dai contenitori-stazione e dall’altro sta mutando la domanda di trasporto che promuove, per le tratte coperte dalle linee dell’Alta Velocità, il treno rispetto all’aereo e alla macchina. In Italia, sulla scia del modello francese, il Gruppo Ferrovie dello Stato RFI, al fine di rendere più confortevole ed efficiente il viaggio sui treni ad Alta Velocità, ha dotato i nuovi treni di numerose innovazioni tecnologiche. Per quanto riguarda l’utilizzo di nuove tecnologie lungo le linee dell’A.V., l’articolo individua la variazione delle abitudini degli utenti al mutare dell’offerta dei servizi predisposti dalle compagnie trasportistiche. La tecnologia utilizzata sui nuovi treni dell’Alta Velocità cambia dunque il concept del viaggio: il valore aggiunto della tecnologia Wi-Fi introdotta sui treni rende la scelta del trasporto su ferro più produttiva rispetto gli altri modi di trasporto quali la macchina o l’aereo. La finalità dell’articolo è da un lato individuare il ruolo urbano assunto delle stazioni dell’Alta Velocità e dall’altro evidenziare come al mutare dell’offerta di trasporto, in termini di servizi offerti ad alto contenuto tecnologico, muta contestualmente anche la domanda di trasporto sul territorio e come tutto questo incida dunque sul governo delle trasformazioni territoriali. Questo è il nuovo importante ruolo della pianificazione: alcune delle nostre più importanti città stanno radicalmente trasformandosi proprio inserendo nei loro cuori le stazioni dell’Alta Velocità come elementi-chiave di accessibilità, vitale per la competitività in tutti i settori economici. Allo stesso modo le stazioni

  11. Estabilidad y funcionalidad de sellantes dentales en altas temperaturas ambientales

    OpenAIRE

    Mishina, Anastasia; Mayelín Guerra, Rosa; Durán Ramos, Ivette; Juan D. Sabatier

    2000-01-01

    Los sellantes dentales son materiales que se emplean en estomatología para sellar las fosas y fisuras oclusales de los dientes y evitar la adherencia del estreptococus mutans agente que produce la caries dental. Estos materiales se suministran en dos partes que al mezclarse producen el endurecimiento de la resina. Sin embargo, estos productos presentan dificultades para su comercialización en los países tropicales, debido a que las altas temperaturas ambientales traen problemas en...

  12. Luces y sombras de la lectura en voz alta

    OpenAIRE

    Cassany, Daniel

    2007-01-01

    En el siguiente artículo aborda una práctica tan extendida en las aulas de todos los niveles educativos como es la lectura en voz alta. A partir de su experiencia personal y profesional, formula un análisis ameno, provocador y fundamentado, una constante en sus textos y conferencias, que suscitará en el lector docente nuevas perspectivas acerca de su trabajo.

  13. Cócs. Hallmark of the Terra Alta

    Directory of Open Access Journals (Sweden)

    Maria Del Loreto Meix

    2004-04-01

    Full Text Available This article looks at the traditional cake making in the Terra Alta (Catalonien area linked to festivities, and in particular the pastries usually made. In this area the pastries are known as cócs, a word common to Terra Alta and the neighbouring districts of Ribera d'Ebre and the Priorat. Locally produced mistelle, sweet or rancid wine is served with the pastries. Nowadays, the bakeries and cake makers in the area's towns and villages also produce traditionally crafted products, that used only to be homemade.The article, resulting from the final degree project produced by the author for her Humanities degree at the UOC, offers a privileged look at the richness of the Terra Alta in terms of its gastronomic history, customs and its high regard for its cakes. The author, who has previous experience in the field, places the specific aspects of Terra Alta cake making in the context of the Mediterranean cultures with common roots dating back to the ancient and medieval worlds and which still have an easily identifiable "family feel", whilst looking, from an ethnographic point of view, at what she calls the "world of wheat" in the area, (the dough for bread, the craft of the baker, the ovens and other tools, and the associated traditions, among other things. In short, she rescues a living part of the local day-to-day activities and places it under the microscope of food history, whilst providing information that may well be of interest for study from other points of view.

  14. Los colosos del campo: tractores de alta potencia

    OpenAIRE

    Moya Gonzalez, Adolfo; Diezma Iglesias, Belen

    2014-01-01

    Revisión y descripción de las principales características de los tractores de alta potencia en el sector agrícola español. La agricultura profesional es una empresa compleja y la inversión en formación de los agentes implicados en el sector (agricultores e ingenieros) es la llave para conseguir aprovechar toda la tecnología disponible y optimizar los recursos usados.

  15. Cuaderno de Prácticas: Altas Capacidades

    OpenAIRE

    García Fernández, José Manuel; Vicent Juan, Maria; Gonzálvez Macià, Carolina

    2016-01-01

    Este material, centrado en el estudio de las Altas Capacidades, pretende favorecer la adquisición de destrezas en el conocimiento e intervención en el ámbito de la educación especial para conocer de primera mano las diferentes formas que se tienen para actuar e intervenir ante niños con necesidades específicas de apoyo educativo.

  16. The Plastic Tension Field Method

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    This paper describes a calculation method for steel plate girders with transverse web stiffeners subjected to shear. It may be used for predicting the failure load or, as a design method, to determine the optimal amount of internal web stiffeners. The new method is called the plastic tension field...... method. The method is based on the theory of plasticity and is analogous to the so-called diagonal compression field method developed for reinforced concrete beams with transverse stirrups, which is adopted in the common European concrete code (Eurocode 2). Many other theories have been developed...

  17. Surface tension driven convection experiment

    Science.gov (United States)

    Ostrach, Simon; Kamotani, Yasuhiro

    1988-01-01

    Thermocapillary flow is driven by a thermally induced surface tension variation along a liquid free surface. In the Earth-gravity environment such flows are usually overshadowed by buoyancy driven flows, but at reduced gravity conditions their influence could be significant. A comprehensive theoretical and experimental research program was stated 12 years ago and is still being continued. Past work done at Case Western Reserve University as well as work done by others is reviewed. The justification for low-gravity experiments is presented.

  18. Axelrod's Model with Surface Tension

    CERN Document Server

    Pace, Bruno

    2012-01-01

    In this work we propose a subtle change in Axelrod's model for the dissemination of culture. The mechanism consists of excluding non-interacting neighbours from the set of neighbours out of which an agent is drawn for potential cultural interactions. Although the alteration proposed does not alter topologically the configuration space, it yields significant qualitative changes, specifically the emergence of surface tension, driving the system in some cases to metastable states. The transient behaviour is considerably richer, and cultural regions have become stable leading to the formation of different spatio-temporal structures. A new metastable "glassy" phase emerges between the globalised phase and the polarised, multicultural phase.

  19. Application of high pressure sodium lamps in facilities with variable voltage; Aplicacion de lamparas de sodio de alta presion en instalaciones con voltaje variable

    Energy Technology Data Exchange (ETDEWEB)

    Dorr, D and others [Fideicomiso para el Ahorro de la Energia Electrica (Mexico)

    2001-06-01

    This article presents the results of laboratory tests to determine the effects of the depressions, interruptions, and fluctuations of tension in the high-pressure sodium vapor (HPS) lamps and ballasts. The form in which these lamps react to the depressions and interruptions in the laboratory, is compared with a model of a real electrical ambient created from data obtained during three recent studies on quality of the electrical service in North America. This work shows how the immunity of this lamp to the tension variations depends significantly on its age and on the type of ballast. [Spanish] Este articulo presenta los resultados de pruebas de laboratorio para determinar los efectos de las depresiones, interrupciones, y fluctuaciones de tension en las lamparas de vapor de sodio a alta presion (HPS) y balastros. La forma en que estas lamparas reaccionan a las depresiones e interrupciones en el laboratorio, se compara con un modelo de un ambiente electrico real creado a partir de datos recabados durante tres estudios recientes sobre calidad del servicio electrico en Norteamerica. Este trabajo muestra como la inmunidad de esta lampara a las variaciones de tension depende significativamente de su edad y del tipo de balastro.

  20. [Tension headache--a review].

    Science.gov (United States)

    Pfaffenrath, V; Wermuth, A; Pöllmann, W

    1988-12-01

    Tension headache (TH) is an ill-defined headache syndrome, characterized by bilateral, daily headaches with fronto-occipital localisation. TH is often accompanied by a migraine and an abuse of analgesics and/or ergotamine. In the etiology of TH vascular, muscular and psychogenic factors are assumed. Floating transitions to common migraine are discussed. The increased muscle tension is not specific for TH, but more probably a consequence of TH. In addition a decrease of the pain threshold with a deficiency of the antinociceptive system is supposed. The efficacy of tricyclic antidepressives in TH is based on potentiation of serotonergic and noradrenergic mechanisms and - besides their analgetic potencies - upon an increase of the pain threshold. TH prophylaxis is indicated if patients suffer from TH more than ten times per month. Medication are tricyclic antidepressives of the amitriptyline-type. Prophylaxis of TH can only be successful if a simultaneous abuse of analgesics and/or ergotamine is discontinued. In addition, EMG-biofeedback, as well as relaxation - and vasoconstriction training might be helpful in specific cases. PMID:3069680

  1. Update on normal tension glaucoma

    Directory of Open Access Journals (Sweden)

    Jyotiranjan Mallick

    2016-01-01

    Full Text Available Normal tension glaucoma (NTG is labelled when typical glaucomatous disc changes, visual field defects and open anterior chamber angles are associated with intraocular pressure (IOP constantly below 21 mmHg. Chronic low vascular perfusion, Raynaud's phenomenon, migraine, nocturnal systemic hypotension and over-treated systemic hypertension are the main causes of normal tension glaucoma. Goldmann applanation tonometry, gonioscopy, slit lamp biomicroscopy, optical coherence tomography and visual field analysis are the main tools of investigation for the diagnosis of NTG. Management follows the same principles of treatment for other chronic glaucomas: To reduce IOP by a substantial amount, sufficient to prevent disabling visual loss. Treatment is generally aimed to lower IOP by 30% from pre-existing levels to 12-14 mmHg. Betaxolol, brimonidine, prostaglandin analogues, trabeculectomy (in refractory cases, systemic calcium channel blockers (such as nifedipine and 24-hour monitoring of blood pressure are considered in the management of NTG. The present review summarises risk factors, causes, pathogenesis, diagnosis and management of NTG.

  2. Etiological factors for muscle tension dysphonia

    OpenAIRE

    Kušar, Rozalija

    2012-01-01

    This thesis discusses muscle tension dysphonia and etiological factors for its emergence. Muscle tension dysphonia is a consequence of irregular formation of the sound and is connected to increased and unnecessary muscle tension and phonation, and is usually without any anatomical and peripheral neurological irregularities and also without any changes on the mucous membrane. In the theoretical part of this thesis voice disorders and various classifications of voice disorders that occur in the...

  3. Surface tension and dynamics of fingering patterns

    OpenAIRE

    Magdaleno, F. X.; Casademunt, J.

    1997-01-01

    We study the minimal class of exact solutions of the Saffman-Taylor problem with zero surface tension, which contains the physical fixed points of the regularized (non-zero surface tension) problem. New fixed points are found and the basin of attraction of the Saffman-Taylor finger is determined within that class. Specific features of the physics of finger competition are identified and quantitatively defined, which are absent in the zero surface tension case. This has dramatic consequences f...

  4. Surface tension profiles in vertical soap films

    OpenAIRE

    Adami, N.; Caps, H.

    2013-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed introducing deformable elastic objets in the films. The shape adopted by those objects set in the film can be related to the surface tension value at a given vertical position by numerical solving of adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position in the soap film can be reproduced by simple modeling taking into acco...

  5. Influence of surface tension to mass transfer

    International Nuclear Information System (INIS)

    Based on the principle of pressure gradient diffusion, the mechanism of the influence of surface tension on interphase mass transfer was brought forward, and a mathematical description of the influence was presented exploringly. Finally, relating to industrial applications, the influence of surface tension on oxygen deaerating in the atomizing section and in the bubble sections was introduced, and the influence of surface tension on atomizing absorption was pointed out as well

  6. Anisotropic surface tension of buckled fluid membrane

    OpenAIRE

    Noguchi, Hiroshi

    2011-01-01

    Solid sheets and fluid membranes exhibit buckling under lateral compression. Here, it is revealed that fluid membranes have anisotropic buckling surface tension contrary to solid sheets. Surprisingly, the surface tension perpendicular to the buckling direction shows stronger dependence than that parallel to it. Our theoretical predictions are supported by numerical simulations of a meshless membrane model. This anisotropic tension can be used to measure the membrane bending rigidity. It is al...

  7. Surface tension profiles in vertical soap films

    CERN Document Server

    Adami, N

    2013-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed introducing deformable elastic objets in the films. The shape adopted by those objects set in the film can be related to the surface tension value at a given vertical position by numerical solving of adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position in the soap film can be reproduced by simple modeling taking into account film thickness measurements.

  8. On Surface Tension for Compact Stars

    Indian Academy of Sciences (India)

    R. Sharma; S. D. Maharaj

    2007-06-01

    In an earlier analysis it was demonstrated that general relativity gives higher values of surface tension in strange stars with quark matter than neutron stars. We generate the modified Tolman–Oppenheimer–Volkoff equation to incorporate anisotropic matter and use this to show that pressure anisotropy provides for a wide range of behaviour in the surface tension than is the case with isotropic pressures. In particular, it is possible that anisotropy drastically decreases the value of the surface tension.

  9. TransForm: TransAlta 2000 annual report

    International Nuclear Information System (INIS)

    Financial information from TransAlta Corp. was presented along with a review of their operations throughout 2000 and a summary of the how the electric utility is doing in terms of power generation, independent power producers, transmission and energy marketing. The utility has changed from a regulated vertically integrated utility into one of Canada's largest non-regulated electric power generators. The utility sold its retail businesses in Alberta and New Zealand and now focuses on coal and hydro generation, gas generation, high-voltage transmission and energy marketing. The newly constructed Centralia, Washington generation facility was brought on line with 1,340 MW in May 2000, on time and on budget. This was the platform to diversify their generation into the United States. The utility reported a solid financial year with $177.9 million in earnings from continuing operations, an 83 per cent increase from 1999, driven mostly by the results of Centralia and power marketing and trading businesses. A financial loss was suffered when the Wabamum power plant in Alberta was shut down for several months to repair a boiler. The utility made excellent progress toward their goal of 15,000 megawatts by 2005 by starting with the construction of what will be one of Canada's largest cogeneration facilities at Sarnia, Ontario. TransAlta also commissioned a 360 MW cogeneration facility at Poplar Creek at Suncor's Fort McMurray oil sand facility. TransAlta also has an excellent track record in developing power generation projects internationally. refs., tabs., figs

  10. HILBERTIAN APPROACH FOR UNIVARIATE SPLINE WITH TENSION

    Institute of Scientific and Technical Information of China (English)

    A.Bouhamidi

    2001-01-01

    In this work,a new approach is proposed for constructing splines with tension.The basic idea is in the use of distributions theory,which allows us to define suitable Hilbert spaces in which the tension spline minimizes some energy functional.Classical orthogonal conditions and characterizations of the spline in terms of a fundamental solution of a differential operator are provided.An explicit representation of the tension spline is given.The tension spline can be computed by solving a linear system.Some numerical examples are given to illustrate this approach.

  11. Surface Tension Calculation of Undercooled Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (xNi=0.42) and Ni-Fe (xNi=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental data is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.

  12. Alta disponibilidad para componentes de fabricación

    OpenAIRE

    Maciá Pérez, Francisco; Marcos Jorquera, Diego; Gilart Iglesias, Virgilio

    2006-01-01

    A medida que las tecnologías de la información van calando en el tejido productivo industrial, tanto más compleja se vuelve su organización. Es imprescindible introducir sistemas de gestión proactivos y autogestionados que aseguren su funcionamiento continuado y, en consecuencia, la continuidad en el negocio. En este artículo se propone un sistema de regeneración de los elementos de producción industrial que traslada el concepto de alta disponibilidad a los niveles de fabricación de la organi...

  13. Perfil docente para alumnos/as con altas capacidades

    OpenAIRE

    María Leonor Conejeros-Solar; María Paz Gómez-Arizaga; Elizabeth Donoso-Osorio

    2013-01-01

    El presente artículo tiene por objeto determinar un perfil de competencias docentes construido desde la percepción de estudiantes con altas capacidades pertenecientes a un programa universitario para talentos académicos. Se utiliza una metodología cualitativa con una estrategia documental de carácter retrospectivo. Los resultados indican que los estudiantes realizan una evaluación profunda sobre la docencia, incluyendo elementos pedagógicos como flexibilidad, ritmo e integración teoría-prácti...

  14. Vulnerabilidad en la cuenca alta del rio Lerma

    OpenAIRE

    Cedeño Valdiviezo, Alberto; Torres Lima, Pablo

    2013-01-01

    La subcuenca Alta del Río Lerma en el Estado de México, importante abastecedor de agua para la Ciudad de México, ha estado expuesta a una fuerte contaminación en los últimos años, misma que ha tenido como consecuencia el Cambio Climático y los consecuentes problemas de salud pública que se están manifestando de diferentes maneras. No obstante, el Estado Mexicano insiste en seguir apoyando a empresas trasnacionales asociadas al cultivo de transgénicos, producción de plaguicidas, pesticidas y P...

  15. Matrices estructuradas y alta precisión relativa

    OpenAIRE

    Barreras Peral, Álvaro; Peña Ferrández, Juan Manuel

    2014-01-01

    Esta memoria se enmarca, dentro del Algebra Lineal Numérica, en el campo de estudio de métodos numéricos adaptados a clases de matrices con estructura especial, que es un campo que muestra una intensa y creciente actividad investigadora. Concretamente, considerará clases de matrices para las que se encontrarán métodos numéricos cuyo cálculo se podrá llevar a cabo con alta precisión relativa. Conseguir cálculos precisos es una propiedad muy deseable para cualquier método numérico. El ideal es ...

  16. Proyecto de Historia como respuesta educativa a las altas capacidades

    OpenAIRE

    Miguel Yoldi, Yohanna

    2014-01-01

    Este trabajo presenta una propuesta de intervención en el aula que responde a las necesidades educativas del alumnado con altas capacidades, desde una escuela inclusiva. Para realizarlo, nos hemos basado en dos autores: Roger J. Sternberg y Joseph S. Renzulli, que no sólo definen las características y necesidades educativas de este colectivo, sino que también proponen posibles respuestas que respondan a su forma de aprender. Desde el área de Ciencias Sociales, apostamos por el aprendizaje bas...

  17. Todos iguales, todos diferentes. Altas capacidades en el aula.

    OpenAIRE

    Soloaga Martín, Beatriz

    2012-01-01

    El presente trabajo se centra en el alumnado de altas capacidades y las posibilidades de atención en el marco del modelo de escuela inclusiva. Se comienza explicando las características de estos alumnos, los estereotipos que existen sobre ellos y las disincronías que es frecuente encontrar en su desarrollo. Se sigue la clasificación de varios autores para distinguir entre superdotación y talento viendo las diferencias significativas que existen entre ellos. De forma breve se ha...

  18. Tensions of Corporate Social Responsibility

    DEFF Research Database (Denmark)

    Strand, Robert

    I engaged with the top management team (TMT) and employees of American Cafes Corporation as an action/intervention researcher in the 20 months immediately following the TMT’s decision to formalize the company’s corporate social responsibility (CSR) activities. This led to the establishment...... of a “CSR bureaucracy” at American Cafes. I explore why the TMT decided to formalize its CSR activities and how the establishment of a CSR bureaucracy affected activities. I employ the Weberian distinction between formal and substantive rational to identify and describe tensions that become apparent when...... CSR agenda is considered, which brings with it a multiplicity of substantively rational ends for which the corporation could pursue. I show the CSR bureaucracy can create a space for reflection in which the multiplicity of substantively rational ends can be considered, negotiated, and selected...

  19. [Tension pneumomediastinum and tension pneumothorax following tracheal perforation during cardiopulmonary resuscitation].

    Science.gov (United States)

    Buschmann, C T; Tsokos, M; Kurz, S D; Kleber, C

    2015-07-01

    Tension pneumothorax can occur at any time during cardiopulmonary resuscitation (CPR) with external cardiac massage and invasive ventilation either from primary or iatrogenic rib fractures with concomitant pleural or parenchymal injury. Airway injury can also cause tension pneumothorax during CPR. This article presents the case of a 41-year-old woman who suffered cardiopulmonary arrest after undergoing elective mandibular surgery. During CPR the upper airway could not be secured by orotracheal intubation due to massive craniofacial soft tissue swelling. A surgical airway was established with obviously unrecognized iatrogenic tracheal perforation and subsequent development of tension pneumomediastinum and tension pneumothorax during ventilation. Neither the tension pneumomediastinum nor the tension pneumothorax were decompressed and accordingly resuscitation efforts remained unsuccessful. This case illustrates the need for a structured approach to resuscitate patients with ventilation problems regarding decompression of tension pneumomediastinum and/or tension pneumothorax during CPR. PMID:26036317

  20. [Tension pneumomediastinum and tension pneumothorax following tracheal perforation during cardiopulmonary resuscitation].

    Science.gov (United States)

    Buschmann, C T; Tsokos, M; Kurz, S D; Kleber, C

    2015-07-01

    Tension pneumothorax can occur at any time during cardiopulmonary resuscitation (CPR) with external cardiac massage and invasive ventilation either from primary or iatrogenic rib fractures with concomitant pleural or parenchymal injury. Airway injury can also cause tension pneumothorax during CPR. This article presents the case of a 41-year-old woman who suffered cardiopulmonary arrest after undergoing elective mandibular surgery. During CPR the upper airway could not be secured by orotracheal intubation due to massive craniofacial soft tissue swelling. A surgical airway was established with obviously unrecognized iatrogenic tracheal perforation and subsequent development of tension pneumomediastinum and tension pneumothorax during ventilation. Neither the tension pneumomediastinum nor the tension pneumothorax were decompressed and accordingly resuscitation efforts remained unsuccessful. This case illustrates the need for a structured approach to resuscitate patients with ventilation problems regarding decompression of tension pneumomediastinum and/or tension pneumothorax during CPR.

  1. Technology for Salt Production in the Mixteca Alta

    Directory of Open Access Journals (Sweden)

    Ricardo Antonio León Hernández

    2015-01-01

    Full Text Available Salt production in the Mixteca Alta is a traditional means of production from prehispanic period, which, despite the economic transformation processes in the colonial period, remained significant features of the traditional process, based on the documented similar models from other productive regions in Mexico. The salt in the novohispanic period was considered a major consumption economic asset due to its use in production processes for the production of new economic products that supported the economy of preindustrial societies (Terán, 2011, p. 71; Williams, 2008. Technology refers to the knowledges for solving human needs arising lifestyle of the cultural groups that develop them. The resources of the natural environment underpin the means of labor that man requires to perform its activities, including economic. The means of production and production processes are technological developments, which involve elements of tangible and intangible order. The study of work processes for salt extraction, are significantly related to the processes of technological evolution that man has developed for the use of natural resources. The economic activities of the primary sector are examples of how humans culturally and economically were inserted in the natural environment (Malpica, 2008, p. 59. This analysis presents a historiographical approach to the study of the processes and the technology required for the extraction of salt in the Mixteca Alta.

  2. Effect of Gravity on Surface Tension

    Science.gov (United States)

    Weislogel, M. M.; Azzam, M. O. J.; Mann, J. A.

    1998-01-01

    Spectroscopic measurements of liquid-vapor interfaces are made in +/- 1-g environments to note the effect of gravity on surface tension. A slight increase is detected at -1-g0, but is arguably within the uncertainty of the measurement technique. An increased dependence of surface tension on the orientation and magnitude of the gravitational vector is anticipated as the critical point is approached.

  3. Delayed tension pneumothorax complicating staphylococcal pneumonia.

    OpenAIRE

    Yates, S. P.; Morcos, S. K.

    1988-01-01

    A case is described in which a tension pneumothorax complicated staphylococcal pneumonia 11 months after its onset. The delayed and subacute/chronic nature of the tension pneumothorax is unusual. The case also highlights the difficult differential diagnosis between subpleural lung cysts and encysted pneumothorax.

  4. Tension and robustness in multitasking cellular networks.

    Directory of Open Access Journals (Sweden)

    Jeffrey V Wong

    Full Text Available Cellular networks multitask by exhibiting distinct, context-dependent dynamics. However, network states (parameters that generate a particular dynamic are often sub-optimal for others, defining a source of "tension" between them. Though multitasking is pervasive, it is not clear where tension arises, what consequences it has, and how it is resolved. We developed a generic computational framework to examine the source and consequences of tension between pairs of dynamics exhibited by the well-studied RB-E2F switch regulating cell cycle entry. We found that tension arose from task-dependent shifts in parameters associated with network modules. Although parameter sets common to distinct dynamics did exist, tension reduced both their accessibility and resilience to perturbation, indicating a trade-off between "one-size-fits-all" solutions and robustness. With high tension, robustness can be preserved by dynamic shifting of modules, enabling the network to toggle between tasks, and by increasing network complexity, in this case by gene duplication. We propose that tension is a general constraint on the architecture and operation of multitasking biological networks. To this end, our work provides a framework to quantify the extent of tension between any network dynamics and how it affects network robustness. Such analysis would suggest new ways to interfere with network elements to elucidate the design principles of cellular networks.

  5. Alta parasitemia pelo Trypanosoma cruzi em paciente com lupus eritematoso sistêmico

    OpenAIRE

    Santos-Neto Leopoldo Luiz dos; Polcheira Máira F.; Castro Cleudson; Lima Rodrigo Aires Corrêa; Simaan César Kozak; Corrêa-Lima Francisco Aires

    2003-01-01

    É descrito um caso de doença de Chagas com alta parasitemia pelo Trypanosoma cruzi em paciente com lupus eritematoso sistêmico. O xenodiagnóstico foi útil na identificação da parasitemia e o benznidazol foi capaz de reduzir a alta e incomum parasitemia. Em indivíduos com doenças auto-imunes e immunossuprimidos, o benznidazol pode ser uma alternativa no controle da alta parasitemia por Trypanosoma cruzi.

  6. Dialectical tensions in stroke survivor relationships.

    Science.gov (United States)

    Brann, Maria; Himes, Kimberly Leezer; Dillow, Megan R; Weber, Keith

    2010-06-01

    Stroke is an unpredictable and life-altering medical occurrence that causes immediate change in survivors' relationships. This study unearthed dialectical tensions expressed by spouses of stroke survivors and examined how those dialectical tensions compare to those experienced by stroke survivors themselves. Sixteen spouses of stroke survivors participated in interviews, and four tensions ultimately emerged: self-orientation-partner-orientation, realism-idealism, uncertainty-acceptance, and emotional release-emotional reservation. Three dialectical tensions (i.e., uncertainty-acceptance, realism-idealism, self-orientation-partner-orientation) were similar to those communicated by stroke survivors. Recognizing dialectical tensions experienced and shared can open communication lines and ultimately improve the health of individuals and their relationships. PMID:20512714

  7. FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

    Institute of Scientific and Technical Information of China (English)

    J.Z. Zhang; X.P. Zhang

    2007-01-01

    The development of computer controlled continuous rolling process calls for a mathematicalexpression that can express the inequality condition of "constant flow". Tension is the link of thecontinuous rolling process. From the condition of dynamic equilibrium, a differential equation oftension is given out. On the basis of the physical rules established from the industrial practice andexperimental studies, the law of volume constancy, the linear relation of forward slip and tension,the state equation of continuous rolling, the formula of dynamic tension, and the formula of statictension have been obtained. These formulae reflect the functional relations between tensions,thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuousrolling process is a gradually steady, controllable, and measurable dynamic system. An assumptionof predicting the thickness of a steel plate using these tension formulae is also put forward.

  8. Magnetic Tension of Sunspot Fine Structures

    CERN Document Server

    Venkatakrishnan, P

    2010-01-01

    The equilibrium structure of sunspots depends critically on its magnetic topology and is dominated by magnetic forces. Tension force is one component of the Lorentz force which balances the gradient of magnetic pressure in force-free configurations. We employ the tension term of the Lorentz force to clarify the structure of sunspot features like penumbral filaments, umbral light bridges and outer penumbral fine structures. We compute vertical component of tension term of Lorentz force over two active regions namely NOAA AR 10933 and NOAA AR 10930 observed on 05 January 2007 and 12 December 2006 respectively. The former is a simple while latter is a complex active region with highly sheared polarity inversion line (PIL). The vector magnetograms used are obtained from Hinode(SOT/SP). We find an inhomogeneous distribution of tension with both positive and negative signs in various features of the sunspots. The existence of positive tension at locations of lower field strength and higher inclination is compatible...

  9. Dynamical Modeling of Surface Tension

    Science.gov (United States)

    Brackbill, Jeremiah U.; Kothe, Douglas B.

    1996-01-01

    In a recent review it is said that free-surface flows 'represent some of the difficult remaining challenges in computational fluid dynamics'. There has been progress with the development of new approaches to treating interfaces, such as the level-set method and the improvement of older methods such as the VOF method. A common theme of many of the new developments has been the regularization of discontinuities at the interface. One example of this approach is the continuum surface force (CSF) formulation for surface tension, which replaces the surface stress given by Laplace's equation by an equivalent volume force. Here, we describe how CSF formulation might be made more useful. Specifically, we consider a derivation of the CSF equations from a minimization of surface energy as outlined by Jacqmin (1996). This reformulation suggests that if one eliminates the computation of curvature in terms of a unit normal vector, parasitic currents may be eliminated. For this reformulation to work, it is necessary that transition region thickness be controlled. Various means for this, in addition to the one discussed by Jacqmin (1996), are discussed.

  10. Hinting en pantallas de alta resolución

    OpenAIRE

    Rodriguez, D

    2012-01-01

    Las pantallas de alta resolución no son algo nuevo —hay prototipos documentados ya en los años ochenta— pero al parecer ha llegado el momento de implantar esta tecnología: en junio de 2010 Steve Jobs presentó el iPhone 4 con la pantalla Retina como principal novedad: una superfície de 3,5 pulgadas con una densidad de 336 píxeles por pulgada. El ojo humano es incapaz de distinguir los píxeles en una imagen de esa resolución, por lo que el equipo directivo de Apple decidió bautizarla como Retin...

  11. ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS

    Institute of Scientific and Technical Information of China (English)

    夏建中

    1997-01-01

    The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount △τ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount △τ13 where △τ13 is the product k and tensioned load p, i. e. △τ13= kp, where k is a function of two variables x and y. The distributive properties both △τ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.

  12. Surface tension profiles in vertical soap films

    Science.gov (United States)

    Adami, N.; Caps, H.

    2015-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

  13. The Equilibrium Spreading Tension of Pulmonary Surfactant.

    Science.gov (United States)

    Dagan, Maayan P; Hall, Stephen B

    2015-12-01

    Monomolecular films at an air/water interface coexist at the equilibrium spreading tension (γ(e)) with the bulk phase from which they form. For individual phospholipids, γ(e) is single-valued, and separates conditions at which hydrated vesicles adsorb from tensions at which overcompressed monolayers collapse. With pulmonary surfactant, isotherms show that monolayers compressed on the surface of bubbles coexist with the three-dimensional collapsed phase over a range of surface tensions. γ(e) therefore represents a range rather than a single value of surface tension. Between the upper and lower ends of this range, rates of collapse for spread and adsorbed films decrease substantially. Changes during adsorption across this narrow region of coexistence between the two- and three-dimensional structures at least partially explain how alveolar films of pulmonary surfactant become resistant to collapse. PMID:26583569

  14. Transcutaneous oxygen tension in imminent foot gangrene

    DEFF Research Database (Denmark)

    Tønnesen, K H

    1978-01-01

    Transcutaneous oxygen tension at 44 degree C and maximal isotope clearance (90m Tc-pretechnetate + histramine) just proximal to the 1st toe and systolic toe blood pressure (strain gauge) were studied on a tilt table in patients with various degrees of obstructive arteriosclerotic disease. In legs...... with moderate obstruction, the oxygen tension reached zero at a toe systolic blood pressure of 5--10 mmHg (tilt toe up) and reached arterial oxygen tension at about 50 to 70 mmHg (tilt toe down). In legs withsevere arterial obstruction and ischaemic rest pain, oxygen tension rose from zero not before systolic...... toe blood pressure reached 20--50 mmHg. Significant isotope clearance was seen at pressures below the limits just mentioned for both types of patients. This phenomenon here seen of a perfusion without oxygen supply is explained by a gas leak (rendered significant because of the slow flow rate) from...

  15. Notch effects in uniaxial tension specimens

    International Nuclear Information System (INIS)

    Results of a literature survey on the effect of notches on the time-dependent failure of uniaxial tension specimens at elevated temperatures are presented. Particular attention is paid to the failure of notched specimens containing weldments

  16. Modelling Tension Stiffening in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1997-01-01

    with deformations in reinforced concrete disks subjected to pure shear.A physical model for the shear stress-shear strain behaviour of disks, including tension stiffening, is proposed.In the disk model it is assumed that the tensile principal stress in the concrete decreases linearly from the initiation of cracking......Part I of the present thesis deals with crack formation in reinforced concrete and the phenomenon of tension stiffening in concrete tension rods reinforced with deformed bars.Two physical models are presented for uniaxial tension, and they are modified for application on beams subjected to pure...... flexure.In the first model, the yield zone model, it is assumed that the mean crack distance is a descending function of the reinforcement stress in a crack. Furthermore it is assumed that in certain zones between the cracks the concrete is carrying its full effective tensile strength, i.e. the concrete...

  17. On surface tension for compact stars

    OpenAIRE

    Sharma, R.; Maharaj, S. D.

    2007-01-01

    In an earlier treatment it was demonstrated that general relativity gives higher values of surface tension in strange stars with quark matter than neutron stars.We generate the modified Tolman-Oppenheimer-Volkoff equation to incorporate anisotropic matter and use this to show that pressure anisotropy provides for a wide range of behaviour in the surface tension than is the case with isotropic pressures. In particular it is possible that anisotropy drastically decreases the value of the surfac...

  18. Tension Hydrothorax Related to Disseminated Endometriosis

    Directory of Open Access Journals (Sweden)

    AnnaKate Deal, MD

    2016-01-01

    Full Text Available We present the case of a 34-year-old woman presenting to the emergency department (ED with dyspnea, cough, and fever. She was found to have a tension hydrothorax and was treated with ultrasound-guided thoracentesis in the ED. Subsequent inpatient evaluation showed the patient had disseminated endometriosis. Tension hydrothorax has not been previously described in the literature as a complication of this disease.

  19. Oxygen tension level and human viral infections

    Energy Technology Data Exchange (ETDEWEB)

    Morinet, Frédéric, E-mail: frederic.morinet@sls.aphp.fr [Centre des Innovations Thérapeutiques en Oncologie et Hématologie (CITOH), CHU Saint-Louis, Paris (France); Université Denis Diderot, Sorbonne Paris Cité Paris, Paris (France); Casetti, Luana [Institut Cochin INSERM U1016, Paris (France); François, Jean-Hugues; Capron, Claude [Institut Cochin INSERM U1016, Paris (France); Laboratoire d' Hématologie, Hôpital Ambroise Paré, Boulogne (France); Université de Versailles Saint-Quentin en Yvelynes, Versailles (France); Pillet, Sylvie [Laboratoire de Bactériologie-Virologie-Hygiène, CHU de Saint-Etienne, Saint-Etienne (France); Université de Lyon et Université de Saint-Etienne, Jean Monnet, GIMAP EA3064, F-42023 Saint-Etienne, Lyon (France)

    2013-09-15

    The role of oxygen tension level is a well-known phenomenon that has been studied in oncology and radiotherapy since about 60 years. Oxygen tension may inhibit or stimulate propagation of viruses in vitro as well as in vivo. In turn modulating oxygen metabolism may constitute a novel approach to treat viral infections as an adjuvant therapy. The major transcription factor which regulates oxygen tension level is hypoxia-inducible factor-1 alpha (HIF-1α). Down-regulating the expression of HIF-1α is a possible method in the treatment of chronic viral infection such as human immunodeficiency virus infection, chronic hepatitis B and C viral infections and Kaposi sarcoma in addition to classic chemotherapy. The aim of this review is to supply an updating concerning the influence of oxygen tension level in human viral infections and to evoke possible new therapeutic strategies regarding this environmental condition. - Highlights: • Oxygen tension level regulates viral replication in vitro and possibly in vivo. • Hypoxia-inducible factor 1 (HIF-1α) is the principal factor involved in Oxygen tension level. • HIF-1α upregulates gene expression for example of HIV, JC and Kaposi sarcoma viruses. • In addition to classical chemotherapy inhibition of HIF-1α may constitute a new track to treat human viral infections.

  20. Oxygen tension affects lubricin expression in chondrocytes.

    Science.gov (United States)

    Hatta, Taku; Kishimoto, Koshi N; Okuno, Hiroshi; Itoi, Eiji

    2014-10-01

    We assessed the effects of oxygen tension on lubricin expression in bovine chondrocytes and cartilage explants and a role for hypoxia-inducible transcription factor (HIF)-1α in regulating lubricin expression was investigated using a murine chondroprogenitor cell line, ATDC5, and bovine chondrocytes isolated from superficial and middle/deep zones of femoral cartilage. ATDC5 cells and bovine chondrocytes were cultured in micromass under different oxygen tensions (21%, 5%, and 1%). ATDC5 cells and middle/deep zone chondrocytes that initially had low lubricin expression levels were also cultured with or without transforming growth factor (TGF)-β1. Quantitative reverse transcription (RT)-PCR was used to determine lubricin and chondrogenic marker gene mRNA levels and immunohistochemistry was used to assess lubricin protein expression. Explant cartilage plugs cultured under different oxygen tensions were also subjected to immunohistological analysis for lubricin. HIF-1α gene silencing was achieved by electroporatic transfer into ATDC5 cells. A low oxygen tension reduced lubricin gene expression levels in bovine superficial chondrocytes, TGF-β1-treated middle/deep zone chondrocytes, and TGF-β1-treated ATDC5 cells. Lubricin expression in explant cartilage was also suppressed under hypoxia. HIF-1α gene silencing in ATDC5 cells attenuated the lubricin expression response to the oxygen tension. These results corroborate with previous studies that the oxygen tension regulates lubricin gene expression and suggest that HIF-1α plays an important role in this regulation. The normal distribution of lubricin in articular cartilage may be due to the hypoxic oxygen environment of cartilage as it is an avascular tissue. An oxygen tension gradient may be a key factor for engineering cartilage tissue with a layered morphology.

  1. Emergency percutaneous needle decompression for tension pneumoperitoneum

    Directory of Open Access Journals (Sweden)

    Körner Markus

    2011-05-01

    Full Text Available Abstract Background Tension pneumoperitoneum as a complication of iatrogenic bowel perforation during endoscopy is a dramatic condition in which intraperitoneal air under pressure causes hemodynamic and ventilatory compromise. Like tension pneumothorax, urgent intervention is required. Immediate surgical decompression though is not always possible due to the limitations of the preclinical management and sometimes to capacity constraints of medical staff and equipment in the clinic. Methods This is a retrospective analysis of cases of pneumoperitoneum and tension pneumoperitoneum due to iatrogenic bowel perforation. All patients admitted to our surgical department between January 2005 and October 2010 were included. Tension pneumoperitoneum was diagnosed in those patients presenting signs of hemodynamic and ventilatory compromise in addition to abdominal distension. Results Between January 2005 and October 2010 eleven patients with iatrogenic bowel perforation were admitted to our surgical department. The mean time between perforation and admission was 36 ± 14 hrs (range 30 min - 130 hrs, between ER admission and begin of the operation 3 hrs and 15 min ± 47 min (range 60 min - 9 hrs. Three out of eleven patients had clinical signs of tension pneumoperitoneum. In those patients emergency percutaneous needle decompression was performed with a 16G venous catheter. This improved significantly the patients' condition (stabilization of vital signs, reducing jugular vein congestion, bridging the time to the start of the operation. Conclusions Hemodynamical and respiratory compromise in addition to abdominal distension shortly after endoscopy are strongly suggestive of tension pneumoperitoneum due to iatrogenic bowel perforation. This is a rare but life threatening condition and it can be managed in a preclinical and clinical setting with emergency percutaneous needle decompression like tension pneumothorax. Emergency percutaneous decompression is no

  2. Oxygen tension affects lubricin expression in chondrocytes.

    Science.gov (United States)

    Hatta, Taku; Kishimoto, Koshi N; Okuno, Hiroshi; Itoi, Eiji

    2014-10-01

    We assessed the effects of oxygen tension on lubricin expression in bovine chondrocytes and cartilage explants and a role for hypoxia-inducible transcription factor (HIF)-1α in regulating lubricin expression was investigated using a murine chondroprogenitor cell line, ATDC5, and bovine chondrocytes isolated from superficial and middle/deep zones of femoral cartilage. ATDC5 cells and bovine chondrocytes were cultured in micromass under different oxygen tensions (21%, 5%, and 1%). ATDC5 cells and middle/deep zone chondrocytes that initially had low lubricin expression levels were also cultured with or without transforming growth factor (TGF)-β1. Quantitative reverse transcription (RT)-PCR was used to determine lubricin and chondrogenic marker gene mRNA levels and immunohistochemistry was used to assess lubricin protein expression. Explant cartilage plugs cultured under different oxygen tensions were also subjected to immunohistological analysis for lubricin. HIF-1α gene silencing was achieved by electroporatic transfer into ATDC5 cells. A low oxygen tension reduced lubricin gene expression levels in bovine superficial chondrocytes, TGF-β1-treated middle/deep zone chondrocytes, and TGF-β1-treated ATDC5 cells. Lubricin expression in explant cartilage was also suppressed under hypoxia. HIF-1α gene silencing in ATDC5 cells attenuated the lubricin expression response to the oxygen tension. These results corroborate with previous studies that the oxygen tension regulates lubricin gene expression and suggest that HIF-1α plays an important role in this regulation. The normal distribution of lubricin in articular cartilage may be due to the hypoxic oxygen environment of cartilage as it is an avascular tissue. An oxygen tension gradient may be a key factor for engineering cartilage tissue with a layered morphology. PMID:24712343

  3. TransAlta Corporation 1996 annual report : new directions, new opportunities

    International Nuclear Information System (INIS)

    TransAlta Corp. is an energy management company that operates through two subsidiaries: (1) TransAlta Utilities Corp. which owns and operates electricity generation, transmission and distribution assets in Alberta, and (2) TransAlta Energy Corp. which is in the business of electric and thermal energy supply, gas and electricity distribution, energy services and energy marketing in regions of Canada, New Zealand, Australia, Argentina and the United States. This report presents a summary of operations, and provides consolidated financial statements and common share information for 1996. During the year the corporation advanced three significant initiatives (1) operational effectiveness, as shown by impressive productivity increases, and major investments in three independent power projects, (2) improved strategic direction through a review of plans and options, resulting in a clearer, more focused vision of the future, and (3) realignment of the organizational structure by centralizing marketing and sales functions, and establishing a corporate business development group. Details of operational and financial results were provided for both subsidiaries, i. e. TransAlta Utilities and TransAlta Energy. Sales of electric energy for TransAlta Utilities amounted to 27.8 billion kWh; 4.6 billion kWh for TransAlta Energy. Return on equity was 11.4 per cent, down from 11.8 per cent in 1995. Net earnings per common share were $1.14 per share (including one-time items), the same as in 1995. tabs., figs

  4. Damage development in woven fabric composites during tension-tension fatigue

    DEFF Research Database (Denmark)

    Hansen, U.

    1999-01-01

    Impacted woven fabric composites were tested in tension-tension fatigue. In contrast to results from static testing, the effects of low energy impact damage in a fatigue environment were found to be the critical element leading to failure of the specimen. This difference emphasizes the need to id...

  5. INTERFACIAL DEBONDING OF COATED-FIBER-REINFORCED COMPOSITES UNDER TENSION-TENSION CYCLIC LOADING

    Institute of Scientific and Technical Information of China (English)

    Shi Zhifei; Zhou Limin

    2000-01-01

    A new degradation function of the friction coefficient is used. Based on the double shear-lag model and Paris formula, the interfacial damage of coated fiber-reinforced composites under tension-tension cyclic loading is studied. The effects of strength and thickness of the coating materials on the debond stress, debond rate as well as debond length are simulated.

  6. Altas Capacidades en Educación Infantil en Guipúzcoa

    OpenAIRE

    Omaetxebarria-Aldarono, Ainara

    2013-01-01

    El trabajo fin de grado que se presenta a continuación aporta información acerca de las altas capacidades en Educación Infantil y su relación con las inteligencias múltiples. Se propone una perspectiva de la realidad actual del tema en el contexto de la provincia de Guipúzcoa. Las altas capacidades se proponen aludiendo a varios aspectos, entre ellos, se define el término, se aportan características de los alumnos con altas capacidades, se señalan alternativas de intervención en las aulas y s...

  7. Altas capacidades intelectuales. Diagnóstico y seguimiento de una NEE.

    OpenAIRE

    Pérez-i-Martra, Pep

    2013-01-01

    Según la OMS, el 2,3% de la población mundial tiene altas capacidades intelectuales, es decir, en la vida académica de un profesor, éste tendría que descubrir una media de 40 alumnos con capacidades superiores a la media. Saber en qué consisten las altas capacidades y hacer un pre diagnóstico de las mismas será, en muchas ocasiones, trabajo del profesor de secundaria. Pero, ¿tiene éste conocimientos para percatarse de la presencia en clase de un alumno con altas capacidades? ¿Y una vez estudi...

  8. El alumnado con altas capacidades intelectuales: programas de intervención.

    OpenAIRE

    González Arranz, Raquel

    2015-01-01

    El presente Trabajo de Fin de Grado se centra en alumnos considerados de Educación Especial, concretamente en aquellos que poseen Altas Capacidades Intelectuales y las posibilidades de respuesta educativa que se les puede ofrecer dentro del modelo de aula ordinaria. En la primera parte, se afronta el estudio de alumnos con altas capacidades intelectuales en educación primaria. Los temas que se tratan son: conceptualización y definiciones, fundamentación teórica de alumnos con altas capaci...

  9. Sistemas de producción de fresa de altas densidades.

    OpenAIRE

    Ramírez Gómez, Humberto

    2011-01-01

    En México se produce fresa con alta tecnología pero existe escasa investigación sobre la productividad de la fresa en sistemas hidropónicos con altas densidades. El presente estudio se realizó con la finalidad de evaluar la fisiología, rendimiento, calidad y rentabilidad de la fresa de altas densidades en cuatro sistemas hidropónicos. Los tratamientos estudiados fueron: bolsas individuales (BI), vertical con tres tubos (V3T), vertical con cuatro tubos (V4T) y vertical con macetas hidropónicas...

  10. Carbon speciation and surface tension of fog

    Science.gov (United States)

    Capel, P.D.; Gunde, R.; Zurcher, F.; Giger, W.

    1990-01-01

    The speciation of carbon (dissolved/particulate, organic/inorganic) and surface tension of a number of radiation fogs from the urban area of Zurich, Switzerland, were measured. The carbon species were dominated by "dissolved" organic carbon (DOC; i.e., the fraction that passes through a filter), which was typically present at levels of 40-200 mg/L. Less than 10% of the DOC was identified as specific individual organic compounds. Particulate organic carbon (POC) accounted for 26-41% of the mass of the particles, but usually less than 10% of the total organic carbon mass. Inorganic carbon species were relatively minor. The surface tensions of all the measured samples were less than pure water and were correlated with their DOC concentrations. The combination of high DOC and POC and low surface tension suggests a mechanism for the concentration of hydrophobic organic contaminants in the fog droplet, which have been observed by numerous investigators. ?? 1990 American Chemical Society.

  11. Cosmological Spacetimes from Negative Tension Brane Backgrounds

    CERN Document Server

    Burgess, C P; Rey, S J; Tasinato, G

    2002-01-01

    We put forward a viable nonsingular cosmology emerging out of negative-tension branes. The cosmology is based on a general class of solutions in Einstein-dilaton-Maxwell theory, presented in {\\tt hep-th/0106120}. We argue that solutions with hyperbolic or planar symmetry describe gravitational interactions due to a pair of negative-tension $q$-branes. These spacetimes are static near each brane, but become time-dependent and expanding at late times -- in some cases asymptotically approaching flat space. We interpret this expansion as being the spacetime's response to the branes presence. The time-dependent regions provide explicit realizations of cosmological spacetimes having past horizons without naked past singularities, and the past horizons are reminiscent of the S-brane solutions. We prove that the singularities in the static regions are repulsive to timelike geodesics, extract a cosmological `bounce' interpretation, compute the explicit charge and tension of the branes, analyse the classical stability ...

  12. Team tension as a vital sign.

    Science.gov (United States)

    Nason, F

    1981-03-01

    Current efforts to provide comprehensive health care have accentuated the need for new models that integrate the biological, psychological, and social fields. One approach to meeting this need has been the development of health care teams. However, the multidisciplinary perspectives of such teams often result in tension and discord. While this tension may be partly attributable to institutional or professional biases or lack of adequate decision-making techniques, it may also be an essential diagnostic tool for exploring and integrating the paradoxes of the patient's homeostatic system. This approach captures and bridges some of the inadequacies of our prevailing knowledge base. The team's tension can be experienced as an essential empathic connectedness to the patient's life situation. Resolution of the team's internalized conflict becomes a paradigm for the patient's reintegration of his or her own paradoxical or contradictory needs. PMID:7215794

  13. Il programma italiano di ricerche nella alta atmosfera

    Directory of Open Access Journals (Sweden)

    l. BROGLIO

    1962-06-01

    Full Text Available La Commissione per le Ricerche Spaziali, nominata dal ConsiglioNazionale delle Ricerche diciotto mesi fa, ha intrapreso un programmadi studio dell'alta atmosfera a mezzo di razzi sonda. Questa ricerca,che nella attuale prima fase di lavoro e sviluppo deve essere consideratauna delle attività basilari della Commissione, aveva ed ha un duplicescopo: uno scopo diretto, immediato, che consiste nell'acquisizione didati scientifici, in maggior copia possibile, tali da ampliare ed approfondirele attuali conoscenze sulla struttura e sulla dinamica della altaatmosfera.Il secondo scopo è, se così si può dire, proiettato nel futuro. L'organizzazionepredisposta, sia in uomini che in attrezzature ed installazioni,per questa ricerca può considerarsi infatti come il nocciolo di unapiù ampia organizzazione che potrà operare negli anni successivi permaggiori e più impegnativi compiti.I fondi necessari per lo sviluppo del programma di ricerche nell'altaatmosfera sono stati forniti alla Commissione delle Ricerche Spazialiin base ad un accordo fra il C.N.R. e il Comitato Razzi e Missili delMinistero della Difesa, secondo il quale i due Enti si impegnavano acontribuire alle spese necessarie su base paritetica.II C.N.R. stipulò anche un accordo di natura scientifica con l'Entespaziale statunitense N.A.S.A., sia per ottenere dalla Commissione delleRicerche Spaziali un appoggio tecnico, sia per altre finalità di cui siparlerà più diffusamente in seguito.

  14. Surface tension of micellar block copolymer films

    International Nuclear Information System (INIS)

    Surface tensions of micellar block copolymers of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) films are obtained by X-ray diffuse scattering. PS-b-PDMS films on Si substrates with the thicknesses from 36 to 588 nm were investigated at temperatures of 30 - 215 .deg. C. The surface tension reflects the concentration of PDMS micelles which are preferably located at the surface. The molar fraction of PDMS micelles near the surface is estimated by using angle-resolved X-ray photoelectron spectroscopy.

  15. A continuum method for modeling surface tension

    Science.gov (United States)

    Brackbill, J. U.; Kothe, D. B.; Zemach, C.

    1992-01-01

    In the novel method presented for modeling the effects of surface tension on fluid motion, the interfaces between fluids with different, color-represented properties are finite-thickness transition regions across which the color varies continuously. A force density proportional to the surface curvature of constant color is defined at each point in the transition region; this force-density is normalized in such a way that the conventional description of surface tension on an interface is recovered when the ratio of local transition-reion thickness to local curvature radius approaches zero. The properties of the method are illustrated by computational results for 2D flows.

  16. Surface tension of tin-lithium alloys

    International Nuclear Information System (INIS)

    Temperature and concentration dependences of surface tension of tin-lithium alloys in the range of temperatures 250-410 deg C and concentrations 6.3-15.0 at. % Li were measured by the big drop method. It was ascertained that lithium is a surfactant component of Sn-Li system. Positive sign of surface tension temperature coefficients suggests prevailing lithium desorption from the liquid alloy surface with temperature increase. Calculated value of maximum lithium adsorption in its alloys with tin, containing about 4 at. % Li, makes up 8.5 x 10-6 mol/m2

  17. Audiitor kaebas Alta Capitali arve pärast Läti kohtusse / Henrik Ilves

    Index Scriptorium Estoniae

    Ilves, Henrik

    2008-01-01

    Eesti Päevalehe andmetel kaebas rahvusvaheline audiitorfirma Ernst & Young Lätis kohtusse investeerimisfirma Alta Capital, kuna firma ei ole maksnud esitatud arvet. Nõude suuruseks on 4,69 miljonit krooni

  18. A progressive reduce tension method to fabricate Bradbury-Nielsen gates with uniform tension

    CERN Document Server

    Kai, Ni; Zhou, Yu

    2015-01-01

    Bradbury-Nielsen gates (BNG) which consist of two interleaved and electrically isolated sets of wires can be used to modulate the beams of charged particles, particularly ion beams in mass spectrometry and ion mobility spectrometry. The wires of BNG with uniform tension is critical to make sure the BNG work reliable and robust. In our previous work, we have analyzed the problem of wires tension non-uniform that exists in the traditional sequentially winding methods when the metal wire's elastic modulus is much larger than insulations substrate's and developed a template-based transfer method to solve this problem. In this study, we proposed a progressive reduce tension method which does not need template to fabricate BNG with uniform tension. First input the initial parameters to calculate the final progressive reduce tension sequence (FA(i)) through program; then sequentially adjust the weight set according to FA(i) to construct a BNG with uniform tension wires through a home-built device. Wires tension non-...

  19. Surface tension in Kac glass models

    International Nuclear Information System (INIS)

    In this paper we study a distance-dependent surface tension, defined as the free-energy cost for putting metastable states at a given distance. This will be done in the framework of a disordered microscopic model with Kac interactions that can be solved in the mean-field limit

  20. Surface Tension in Kac Glass Models

    OpenAIRE

    Zarinelli, Elia; Franz, Silvio

    2009-01-01

    In this paper we study a distance-dependent surface tension, defined as the free-energy cost to put metastable states at a given distance. This will be done in the framework of a disordered microscopic model with Kac interactions that can be solved in the mean-field limit.

  1. Surface tension of undercooled liquid cobalt

    International Nuclear Information System (INIS)

    This paper provides the results on experimentally measured and numerically predicted surface tensions of undercooled liquid cobalt. The experiments were performed by using the oscillation drop technique combined with electromagnetic levitation. The simulations are carried out with the Monte Carlo (MC) method, where the surface tension is predicted through calculations of the work of cohesion, and the interatomic interaction is described with an embedded-atom method. The maximum undercooling of the liquid cobalt is reached at 231 K (0.13Tm) in the experiment and 268 K (0.17Tm) in the simulation. The surface tension and its relationship with temperature obtained in the experiment and simulation are σexp=1.93-0.000 33 (T-Tm) N m-1 and σcal=2.26-0.000 32 (T-Tm) N m-1 respectively. The temperature dependence of the surface tension calculated from the MC simulation is in reasonable agreement with that measured in the experiment. (author)

  2. Measuring the surface tension of soap bubbles

    Science.gov (United States)

    Sorensen, Carl D.

    1992-01-01

    The objectives are for students to gain an understanding of surface tension, to see that pressure inside a small bubble is larger than that inside a large bubble. These concepts can be used to explain the behavior of liquid foams as well as precipitate coarsening and grain growth. Equipment, supplies, and procedures are explained.

  3. Dynamic Surface Tensions of Fluorous Surfactant Solutions

    Institute of Scientific and Technical Information of China (English)

    高艳安; 侯万国; 王仲妮; 李干佐; 韩布兴; 张高勇; 吕锋锋

    2005-01-01

    Dynamic surface properties of aqueous solutions of cationic fluorous surfactant CF3CF2CF20(CF(CF3)CF2O)2CF(CF3)CONH(CHE)3N+(C2H5)2CH3I- (abbrev. FC-4 ) were reported. The critical micelle concentration (cmc)(3.6×10-5 mol/L) and equilibdum surface tensions γeq were measured by Krtlss K12 tension apparatus. Dynamic surface tension γ(t) was measured in the range of 15 ms to 200 s using the MBP tensiometer. The surface excess Γ,as a function of concentration, was obtained from equilibrium tensiometry using the Gibbs equation. Data from these experiments were combined to analyze the γ(t) decays according to the asymptotic Ward and Tordai equation.The results show that at the initial adsorption stage, the dynamic surface tension data were all consistent with this diffusion-controlled mechanism, and at the end of the adsorption process, there were some evidences for an adsorption barrier, suggesting a mixed diffusion-controlled adsorption mechanism. Using measured quantities, the barrier strength was estimated as between 25 and 35 kJ/mol at 25℃. The surface pressure plays an important role in contributing to the barrier.

  4. Normal tension glaucoma and Alzheimer disease

    DEFF Research Database (Denmark)

    Bach-Holm, Daniella; Kessing, Svend Vedel; Mogensen, Ulla;

    2012-01-01

    PURPOSE: To investigate whether normal tension glaucoma (NTG) is associated with increased risk of developing dementia/Alzheimer disease (AD). METHODS: A total of 69 patients with NTG were identified in the case note files in the Glaucoma Clinic, University Hospital of Copenhagen (Rigshospitalet...

  5. Robust atomistic calculation of dislocation line tension

    Science.gov (United States)

    Szajewski, B. A.; Pavia, F.; Curtin, W. A.

    2015-12-01

    The line tension Γ of a dislocation is an important and fundamental property ubiquitous to continuum scale models of metal plasticity. However, the precise value of Γ in a given material has proven difficult to assess, with literature values encompassing a wide range. Here results from a multiscale simulation and robust analysis of the dislocation line tension, for dislocation bow-out between pinning points, are presented for two widely-used interatomic potentials for Al. A central part of the analysis involves an effective Peierls stress applicable to curved dislocation structures that markedly differs from that of perfectly straight dislocations but is required to describe the bow-out both in loading and unloading. The line tensions for the two interatomic potentials are similar and provide robust numerical values for Al. Most importantly, the atomic results show notable differences with singular anisotropic elastic dislocation theory in that (i) the coefficient of the \\text{ln}(L) scaling with dislocation length L differs and (ii) the ratio of screw to edge line tension is smaller than predicted by anisotropic elasticity. These differences are attributed to local dislocation core interactions that remain beyond the scope of elasticity theory. The many differing literature values for Γ are attributed to various approximations and inaccuracies in previous approaches. The results here indicate that continuum line dislocation models, based on elasticity theory and various core-cut-off assumptions, may be fundamentally unable to reproduce full atomistic results, thus hampering the detailed predictive ability of such continuum models.

  6. Inclusion and Participation: Working with the Tensions

    Directory of Open Access Journals (Sweden)

    Gideon Calder

    2011-12-01

    Full Text Available Democracy is crucially about inclusion: a theory of democracy must account for who is to be included in the democratic process, how, and on what terms. Inclusion, if conceived democratically, is fraught with tensions. This article identifies three such tensions, arising respectively in: (i the inauguration of the democratic public; (ii enabling equal participation; and (iii the relationship between instrumental and non-instrumental accounts of democracy’s value. In each case, I argue, rather than seeking somehow to dissolve or avoid such tensions, theories of democracy should allow us to live with their implications reflexively: to work with them. Such tensions are counter-democratic to the extent that they derail what Nancy Fraser calls “participatory parity,” under which citizens count as “full partners in social interaction.” But the extent to which they do this is not itself dependent on points of paradox in the very idea of inclusion. Such parity relies on complex factors, social and economic, which democratic institutions and procedures will not by themselves address. To achieve full democratic inclusion we must already have addressed such factors; no account of democracy itself, however finely-tuned, will do this.

  7. Tension Tests On Bored Piles In Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2006-01-01

    The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different...

  8. y alta de la subcuenca Cohatán, Chiapas

    Directory of Open Access Journals (Sweden)

    M. Grajales

    2008-01-01

    Full Text Available El estudio consistió en un diagnóstico biofísico (fisiográfico, hidrográfico, uso actual del suelo, cobertura vegetal y socioeconómico (infraestructura social y productiva con actividades en la subcuenca Cohatán, localizado en las estribaciones de la Sierra del Soconusco Chiapas, para saber la situación que guarda y generar acciones de rehabilitación, a mediano y largo plazo. Esta subcuenca se extiende desde 350 a los 4,080 msnm, con 42 comunidades, que abarcan los municipios de Tapachula, Motozintla y Cacahotán, Chiapas; tiene una densidad de 1.2 hab/ha, con suelo de origen volcánico formado del Cenozoico terciario de unidad acrisol húmico. El 80% de la superficie presenta clima tropical húmedo y subhúmedo, con relieve de ladera fuerte hasta de 60%, con una erosión hídrica severa de 250 t/ ha/año en 42% de la superficie; tiene 25% de selva, medias altas y perennifolias. La principal actividad económica es la explotación del cultivo de café, desde el área marginal 350 hasta 2,660 msnm. A lo largo del río Cohatán el tipo de desarrollo se sustenta en el uso intensivo de los recursos naturales, originan —a su vez— fuerte deterioro neceambiental, al cambio de vegetación de la selva original por introducción de especies de sombra del café con chalum (Inga spp; en este ecosistema se observa un deficiente uso de tecnología de producción que se refleja en el bajo rendimiento del café, de 8 quintales/ha. El nivel socioeconómico de desarrollo es bajo, con nivel de educación, salud, vivienda y servicios deficientes, así como falta de apoyo social, con carente gestión ambiental

  9. Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading during zebrafish epiboly

    OpenAIRE

    Campinho, Pedro; Behrndt, Martin; Ranft, Jonas; Risler, Thomas; Minc, Nicolas; Heisenberg, Carl-Philipp

    2015-01-01

    Epithelial spreading is a common and fundamental aspect of various developmental and disease-related processes such as epithelial closure and wound healing. A key challenge for epithelial tissues undergoing spreading is to increase their surface area without disrupting epithelial integrity. Here we show that orienting cell divisions by tension constitutes an efficient mechanism by which the enveloping cell layer (EVL) releases anisotropic tension while undergoing spreading during zebrafish ep...

  10. Parametric Instability Analysis of Deepwater Top-Tensioned Risers Considering Variable Tension Along the Length

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; TANG Yougang

    2015-01-01

    Parametric instability of a riser is caused by fluctuation of its tension in time due to the heave motion of floating plat-form. Many studies have tackled the problem of parametric instability of a riser with constant tension. However, tension in the riser actually varies linearly from the top to the bottom due to the effect of gravity. This paper presents the parametric instability analysis of deepwater top-tensioned risers (TTR) considering the linearly varying tension along the length. Firstly, the governing equation of transverse motion of TTR under parametric excitation is established. This equation is reduced to a system of ordinary differential equations by using the Galerkin method. Then the parametric instability of TTR for three calculation models are investigated by ap-plying the Floquet theory. The results show that the natural frequencies of TTR with variable tension are evidently reduced, the pa-rametric instability zones are significantly increased and the maximum allowable amplitude of platform heave is much smaller under the same damping; The nodes and antinodes of mode shape are no longer uniformly distributed along the axial direction and the am-plitude also changes with depth, which leads to coupling between the modes. The combination resonance phenomenon occurs as a result of mode coupling, which causes more serious damage.

  11. Surface and interfacial tension measurement, theory, and applications

    CERN Document Server

    Hartland, Stanley

    2004-01-01

    This edited volume offers complete coverage of the latest theoretical, experimental, and computer-based data as summarized by leading international researchers. It promotes full understanding of the physical phenomena and mechanisms at work in surface and interfacial tensions and gradients, their direct impact on interface shape and movement, and their significance to numerous applications. Assessing methods for the accurate measurement of surface tension, interfacial tension, and contact angles, Surface and Interfacial Tension presents modern simulations of complex interfacial motions, such a

  12. Separation anxiety: Stress, tension and cytokinesis

    International Nuclear Information System (INIS)

    Cytokinesis, the physical separation of a mother cell into two daughter cells, progresses through a series of well-defined changes in morphology. These changes involve distinct biochemical and mechanical processes. Here, we review the mechanical features of cells during cytokinesis, discussing both the material properties as well as sources of stresses, both active and passive, which lead to the observed changes in morphology. We also describe a mechanosensory feedback control system that regulates protein localization and shape progression during cytokinesis. -- Highlights: ► Cytokinesis progresses through three distinct mechanical phases. ► Cortical tension initially resists deformation of mother cell. ► Late in cytokinesis, cortical tension provides stress, enabling furrow ingression. ► A mechanosensory feedback control system regulates cytokinesis.

  13. Separation anxiety: Stress, tension and cytokinesis

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Krithika [Department of Electrical and Computer Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Iglesias, Pablo A., E-mail: pi@jhu.edu [Department of Electrical and Computer Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Robinson, Douglas N., E-mail: dnr@jhmi.edu [Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

    2012-07-15

    Cytokinesis, the physical separation of a mother cell into two daughter cells, progresses through a series of well-defined changes in morphology. These changes involve distinct biochemical and mechanical processes. Here, we review the mechanical features of cells during cytokinesis, discussing both the material properties as well as sources of stresses, both active and passive, which lead to the observed changes in morphology. We also describe a mechanosensory feedback control system that regulates protein localization and shape progression during cytokinesis. -- Highlights: Black-Right-Pointing-Pointer Cytokinesis progresses through three distinct mechanical phases. Black-Right-Pointing-Pointer Cortical tension initially resists deformation of mother cell. Black-Right-Pointing-Pointer Late in cytokinesis, cortical tension provides stress, enabling furrow ingression. Black-Right-Pointing-Pointer A mechanosensory feedback control system regulates cytokinesis.

  14. Surface Tension and Fingering of Miscible Interfaces

    Science.gov (United States)

    Abib, Mohammed; Liu, Jian-Bang; Ronney, Paul D.

    1999-01-01

    Experiments on miscible, buoyantly unstable reaction-diffusion fronts and non-reacting displacement fronts in Hele-Shaw cells show a fingering-type instability whose wavelengths (lambda*) are consistent with an interfacial tension (sigma) at the front caused by the change in chemical composition, even though the solutions are miscible in all proportions. In conjunction with the Saffman-Taylor model, the relation sigma = K/tau, where tau is the interface thickness and K approximately equal 4 +/- 2 x 10(exp -6) dyne, enables prediction of our measured values of lambda* as well as results from prior experiments on miscible interfaces. These results indicate that even for miscible fluids, surface tension is generally a more significant factor than diffusion in interfacial stability and flow characteristics.

  15. Thermal Analysis of Bending Under Tension Test

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Martins, Paulo A.F.; Bay, Niels

    2014-01-01

    during testing is similar to the one in the production tool. A universal sheet tribo-tester has been developed, which can run multiple tests automatically from coil. This allows emulating the temperature increase as in production. The present work performs finite element analysis of the evolution...... and distribution of temperature in the bending under tension test by making use of boundary conditions and calibration values directly measured from experiments. The overall methodology combines 2D and 3D models of the bending under tension test with steady state and transient thermal and thermo......-mechanical procedures. Results show that the proposed methodology applied to a single stroke can effectively and accurately predict the interface temperature in the test tool, thus avoiding the otherwise required thousands of thermo-mechanical FEM analyses of temperature development during testing before thermal steady...

  16. Scaling for interfacial tensions near critical endpoints.

    Science.gov (United States)

    Zinn, Shun-Yong; Fisher, Michael E

    2005-01-01

    Parametric scaling representations are obtained and studied for the asymptotic behavior of interfacial tensions in the full neighborhood of a fluid (or Ising-type) critical endpoint, i.e., as a function both of temperature and of density/order parameter or chemical potential/ordering field. Accurate nonclassical critical exponents and reliable estimates for the universal amplitude ratios are included naturally on the basis of the "extended de Gennes-Fisher" local-functional theory. Serious defects in previous scaling treatments are rectified and complete wetting behavior is represented; however, quantitatively small, but unphysical residual nonanalyticities on the wetting side of the critical isotherm are smoothed out "manually." Comparisons with the limited available observations are presented elsewhere but the theory invites new, searching experiments and simulations, e.g., for the vapor-liquid interfacial tension on the two sides of the critical endpoint isotherm for which an amplitude ratio -3.25+/-0.05 is predicted.

  17. Fatigue In Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Uhre; Hoffmeyer, Preben;

    2004-01-01

    Traditionally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...... mechanism and a mechanism connected to damage introduced in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens and on...... made on dowel type connections that have tension perpendicular to the grain as limiting strength parameter. It is concluded that no significant influence of duration of load is observed w hen the fatigue resistance of small specimens at 0.01 Hz and 0.1 Hz are compared. A weak but inconclusive time...

  18. Vortices and the SU(3) string tension

    OpenAIRE

    Kovács, T. G.; Tomboulis, E. T.

    1998-01-01

    We present simulation results comparing the SU(3) heavy quark potential extracted from the full Wilson loop expectation to that extracted from the expectation of the Wilson loop fluctuation solely by elements of Z(3). The two potentials are found to coincide. This agreement is stable under multiple smoothings of the configurations which remove short distance fluctuations, and thus reflects long-distance physics. It strongly indicates that the asymptotic string tension arises from thick center...

  19. Surface Tension Demonstration Aboard the ISS

    Science.gov (United States)

    2003-01-01

    Astronaut Donald R. Pettit, Expedition Six NASA ISS science officer, photographed this view of a surface tension demonstration using water that is held in place by a metal loop. The experiment took place in the Destiny laboratory on the International Space Station (ISS). The Expedition Six crew was delivered to the station via the Space Shuttle Orbiter Endeavor STS-113 mission which was launched on November 23, 2002.

  20. Surface tension confined liquid cryogen cooler

    Science.gov (United States)

    Castles, Stephen H. (Inventor); Schein, Michael E. (Inventor)

    1989-01-01

    A cryogenic cooler is provided for use in craft such as launch, orbital, and space vehicles subject to substantial vibration, changes in orientation, and weightlessness. The cooler contains a small pore, large free volume, low density material to restrain a cryogen through surface tension effects during launch and zero-g operations and maintains instrumentation within the temperature range of 10 to 140 K. The cooler operation is completely passive, with no inherent vibration or power requirements.

  1. Noncontact surface tension measurement by drop rotation

    OpenAIRE

    Rhim, Won-Kyu; Ishikawa, Takehiko

    2001-01-01

    Validity of the surface tension measurement technique that was proposed by Elleman et al. was experimentally verified. The technique was based on Brown and Scriven's work on the shape evolution of rotating drops. Molten tin and aluminum drops were levitated in high vacuum by the electrostatic levitator and rotated by applying a rotating magnetic field. This technique offers an alternative technique for those liquids where the drop oscillation technique cannot be used. As a demonstration, the ...

  2. Scaling for Interfacial Tensions near Critical Endpoints

    OpenAIRE

    Zinn, Shun-Yong; Fisher, Michael E.

    2004-01-01

    Parametric scaling representations are obtained and studied for the asymptotic behavior of interfacial tensions in the \\textit{full} neighborhood of a fluid (or Ising-type) critical endpoint, i.e., as a function \\textit{both} of temperature \\textit{and} of density/order parameter \\textit{or} chemical potential/ordering field. Accurate \\textit{nonclassical critical exponents} and reliable estimates for the \\textit{universal amplitude ratios} are included naturally on the basis of the ``extende...

  3. A microprocessor based portable bolt tension monitor

    Science.gov (United States)

    Perey, D. F.

    1991-01-01

    A bolt tension monitor (BTM) which uses ultrasonics and a pulsed phase locked loop circuit to measure load-induced acoustic phase shifts which are independent of friction is described. The BTM makes it possible to measure the load in a bolt that was tightened at some time in the past. This capability to recertify a load after-the-fact will help to insure the integrity of a bolted joint.

  4. 2-rational Cubic Spline Involving Tension Parameters

    Indian Academy of Sciences (India)

    M Shrivastava; J Joseph

    2000-08-01

    In the present paper, 1-piecewise rational cubic spline function involving tension parameters is considered which produces a monotonic interpolant to a given monotonic data set. It is observed that under certain conditions the interpolant preserves the convexity property of the data set. The existence and uniqueness of a 2-rational cubic spline interpolant are established. The error analysis of the spline interpolant is also given.

  5. Tensions of Teaching Media Literacy in Teacher Education

    Science.gov (United States)

    Ngomba-Westbrook, Nalova Elaine

    2013-01-01

    This study investigates the tensions a teacher educator faces in facilitating a media literacy teacher education course at the university level. Teaching tensions are conceptualized as a three-tier framework. At the first level, tensions may arise in the selection and application of pedagogies associated with critical and new/21st century…

  6. Acute Tension Pneumothorax Following Cardiac Herniation after Pneumonectomy

    OpenAIRE

    Daniel Steinmann; Eva Rohr; Andreas Kirschbaum

    2010-01-01

    A tension pneumothorax is one of the main causes of cardiac arrest in the initial postoperative period after thoracic surgery. Tension pneumothorax and cardiac herniation must be taken into account in hemodynamically unstable patients after pneumonectomy. We report an unusual case of successful treatment of acute tension pneumothorax following cardiac herniation and intrathoracic bleeding after pneumonectomy.

  7. Niche conservatism of Eulophia alta, a trans-Atlantic orchid species

    Directory of Open Access Journals (Sweden)

    Marta Kolanowska

    2014-03-01

    Full Text Available The genus Eulophia embraces over 230 species distributed through the tropical and subtropical Africa, Asia, Australia and the Americas. In Neotropics it is represented by a sole species – E. alta. The aim of the presented study was to evaluate the difference between ecological niches occupied by American and African populations of this species based on the ecological niche modeling. The similarity between the glacial and present niches occupied by E. alta was calculated and the factors limiting the species occurrence were identified. Areas of seasonal tropical forest, tropical savanna and woodland served as refugia for the studied species during last glacial maximum and they were more widespread in Neotropics than in Africa. No significant niche shift after last glacial maximum was observed. The distribution of E. alta in its whole range is restricted mainly by temperature seasonality. The differences in the niches occupied by African and Neotropical populations of E. alta suggest preglacial disjunction of the species range and independent adaptation of both groups. Despite the significant range disjunction of E. alta the species is characterized by relatively high degree of niche conservatism.

  8. Tension-induced binding of semiflexible biopolymers

    CERN Document Server

    Benetatos, Panayotis; Zippelius, Annette

    2014-01-01

    We investigate theoretically the effect of polymer tension on the collective behavior of reversibly binding cross-links. For this purpose, we employ a model of two weakly bending wormlike chains aligned in parallel by a tensile force, with a sequence of inter-chain binding sites regularly spaced along the contours. Reversible cross-links attach and detach at the sites with an affinity controlled by a chemical potential. In a mean-field approach, we calculate the free energy of the system and find the emergence of a free-energy barrier which controls the reversible (un)binding. The tension affects the conformational entropy of the chains which competes with the binding energy of the cross-links. This competition gives rise to a sudden increase in the fraction of bound sites as the tension increases. We show that this transition is related to the cross-over between weak and strong localization of a directed polymer in a pinning potential. The cross-over to the strongly bound state can be interpreted as a mechan...

  9. Nuclear myosin I regulates cell membrane tension

    Science.gov (United States)

    Venit, Tomáš; Kalendová, Alžběta; Petr, Martin; Dzijak, Rastislav; Pastorek, Lukáš; Rohožková, Jana; Malohlava, Jakub; Hozák, Pavel

    2016-01-01

    Plasma membrane tension is an important feature that determines the cell shape and influences processes such as cell motility, spreading, endocytosis and exocytosis. Unconventional class 1 myosins are potent regulators of plasma membrane tension because they physically link the plasma membrane with adjacent cytoskeleton. We identified nuclear myosin 1 (NM1) - a putative nuclear isoform of myosin 1c (Myo1c) - as a new player in the field. Although having specific nuclear functions, NM1 localizes predominantly to the plasma membrane. Deletion of NM1 causes more than a 50% increase in the elasticity of the plasma membrane around the actin cytoskeleton as measured by atomic force microscopy. This higher elasticity of NM1 knock-out cells leads to 25% higher resistance to short-term hypotonic environment and rapid cell swelling. In contrast, overexpression of NM1 in wild type cells leads to an additional 30% reduction of their survival. We have shown that NM1 has a direct functional role in the cytoplasm as a dynamic linker between the cell membrane and the underlying cytoskeleton, regulating the degree of effective plasma membrane tension. PMID:27480647

  10. A tension stress loading unit designed for characterizing indentation response of single crystal silicon under tension stress

    Science.gov (United States)

    Huang, Hu; Zhao, Hongwei; Shi, Chengli; Hu, Xiaoli; Cui, Tao; Tian, Ye

    2013-09-01

    In this paper, a tension stress loading unit is designed to provide tension stress for brittle materials by combining the piezo actuator and the flexible hinge. The structure of the tension stress loading unit is analyzed and discussed via the theoretical method and finite element simulations. Effects of holding time, the installed specimen and hysteresis of the piezo actuator on output performances of the tension stress loading unit are studied in detail. An experiment system is established by combing the indentation testing unit and the developed tension stress loading unit to characterize indentation response of single crystal silicon under tension stress. Experiment results indicate that tension stress leads to increasing of indentation displacement for the same inden-tation load of single crystal silicon. This paper provides a new tool for studying indentation response of brittle materials under tension stress.

  11. Curved and diffuse interface effects on the nuclear surface tension

    OpenAIRE

    Kolomietz, V. M.; Lukyanov, S. V.; Sanzhur, A. I.

    2011-01-01

    We redefine the surface tension coefficient for a nuclear Fermi-liquid drop with a finite diffuse layer. Following Gibbs-Tolman concept, we introduce the equimolar radius R_e of sharp surface droplet at which the surface tension is applied and the radius of tension surface R_s which provides the minimum of the surface tension coefficient \\sigma. This procedure allows us to derive both the surface tension and the corresponding curvature correction (Tolman length) correctly for the curved and d...

  12. Influence of surface tension on two fluids shearing instability

    CERN Document Server

    Banerjee, Rahul

    2015-01-01

    Using extended Layzer's potential flow model, we investigate the effects of surface tension on the growth of the bubble and spike in combined Rayleigh-Taylor and Kelvin-Helmholtz instability. The nonlinear asymptotic solutions are obtained analytically for the velocity and curvature of the bubble and spike tip. We find that the surface tension decreases the velocity but does not affect the curvature, provided surface tension is greater than a critical value. For a certain condition, we observe that surface tension stabilizes the motion. Any perturbation, whatever its magnitude, results stable with nonlinear oscillations. The nonlinear oscillations depend on surface tension and relative velocity shear of the two fluids.

  13. Toward a general psychological model of tension and suspense

    Directory of Open Access Journals (Sweden)

    Moritz eLehne

    2015-02-01

    Full Text Available Tension and suspense are powerful emotional experiences that occur in a wide variety of contexts (e.g., in music, film, literature, and everyday life. The omnipresence of tension experiences suggests that they build on very basic cognitive and affective mechanisms. However, the psychological underpinnings of tension experiences remain largely unexplained, and tension and suspense are rarely discussed from a general, domain-independent perspective. In this paper, we argue that tension experiences in different contexts (e.g., musical tension or suspense in a movie build on the same underlying psychological processes. We discuss key components of tension experiences and propose a domain-independent model of tension and suspense. According to this model, tension experiences originate from states of conflict, instability, dissonance, or uncertainty that trigger predictive processes directed at future events of emotional significance. We also discuss possible neural mechanisms underlying experiences of tension. The model provides a theoretical framework that can inform future empirical research on tension phenomena.

  14. Surface tension measurement from the indentation of clamped thin films.

    Science.gov (United States)

    Xu, Xuejuan; Jagota, Anand; Paretkar, Dadhichi; Hui, Chung-Yuen

    2016-06-21

    We developed an indentation technique to measure the surface tension of relatively stiff solids. In the proposed method, a suspended thin solid film is indented by a rigid sphere and its deflection is measured by optical interferometry. The film deflection is jointly resisted by surface tension, elasticity and residual stress. Using a version of nonlinear von Karman plate theory that includes surface tension, we are able to separate the contribution of elasticity to the total tension in the film. Surface tension is determined by extrapolating the sum of surface tension and residual stress to zero film thickness. We measured the surface tension of polydimethylsiloxane (PDMS) using this technique and obtained a value of 19.5 ± 3.6 mN m(-1), consistent with the surface energy of PDMS reported in the literature. PMID:27189735

  15. Consumo energético de sistemas de computación de altas prestaciones

    OpenAIRE

    Balladini, Javier; Morán, Marina; Rozas, Claudia; De Giusti, Armando Eduardo; Suppi, Remo; Rexachs del Rosario, Dolores; Luque, Emilio

    2015-01-01

    En la última década, el consumo energético ha dirigido el diseño de todos los sistemas de cómputo, desde dispositivos móviles a los cuales cada vez se le piden más prestaciones que deben ser soportadas por una pequeña batería, hasta los sistemas de Cómputo de Altas Prestaciones (HPC, de High Performance Computing), objeto de nuestro interés, los cuales consumen enormes cantidades de energía. Esta alta demanda energ ética tiene serias consecuencias financieras, medioambientales, y en muchos c...

  16. Neurociências, altas habilidades e implicações no currículo

    OpenAIRE

    Amauri Betini Bartoszeck

    2014-01-01

    http://dx.doi.org/10.5902/1984686X14284O presente estudo inicialmente define e descreve as sub-disciplinas que compõem as neurociências com potenciais aplicações educacionais para crianças e adultos  identificados com altas habilidades. Objetiva-se com uma breve introdução morfofuncional ao sistema nervoso que serve de pano de fundo para auxiliar o entendimento da ponte teórico-experimental da relação de neurociências e altas habilidades. São salientados aspectos da base evolucionista e bioló...

  17. Computación de altas prestaciones: problemáticas y aplicaciones

    OpenAIRE

    Balladini, Javier; Morán, Marina; Rozas, Claudia; Frati, Fernando Emmanuel; De Giusti, Armando Eduardo; Suppi, Remo; Rexachs del Rosario, Dolores; Luque, Emilio

    2016-01-01

    Nuestra investigación está centrada en dos lí- neas. Por un lado, el estudio del consumo energé- tico de los sistemas de Cómputo de Altas Prestaciones (HPC, de High Performance Computing) cuya alta demanda energética tiene serias consecuencias nancieras, medioambientales, y en muchos casos también sociales. El aumento de la e ciencia energética de los sistemas de HPC no solo proviene de las nuevas arquitecturas hardware, también está involucrado el software, quien debe gestionar y con gurar ...

  18. Estudo da miscibilidade das misturas de PHB e PLA, com um PHB de alta polidispersividade

    Directory of Open Access Journals (Sweden)

    Wagner Mauricio Pachekoski

    2015-02-01

    Full Text Available Neste trabalho, foi estudada a miscibilidade de misturas de um PHB constituído de frações de alta e baixa massa molar com um PLA de alta massa molar. Os materiais extrudados foram analisados pelas técnicas de calorimetria exploratória diferencial (DSC, espectroscopia dielétrica (DE e análises dinâmico-mecânicas (DMA. A partir dos resultados observou-se o distinto comportamento cristalino das frações de PHB, assim como a miscibilidade parcial do PLA com o PHB de baixa massa molar.

  19. Estudo da miscibilidade das misturas de PHB e PLA, com um PHB de alta polidispersividade

    OpenAIRE

    Wagner Mauricio Pachekoski; Carla Dalmolin; José Augusto Marcondes Agnelli

    2015-01-01

    Neste trabalho, foi estudada a miscibilidade de misturas de um PHB constituído de frações de alta e baixa massa molar com um PLA de alta massa molar. Os materiais extrudados foram analisados pelas técnicas de calorimetria exploratória diferencial (DSC), espectroscopia dielétrica (DE) e análises dinâmico-mecânicas (DMA). A partir dos resultados observou-se o distinto comportamento cristalino das frações de PHB, assim como a miscibilidade parcial do PLA com o PHB de baixa massa molar.

  20. 50 años de alta velocidad en Japón

    OpenAIRE

    Pigem Cameselle, Ramiro

    2008-01-01

    Al inaugurar los 515 kilómetros de línea de alta velocidad entre Tokio y Osaka en octubre de 1964, Japón alcanzó un logro todavía mayor que el de impulsar su propia economía. Abrió una era del transporte completamente nueva con un innovador sistema ferroviario. Con ello prestó un innegable servicio al mundo ferroviario, desencadenando un auge global de la alta velocidad e inyectando aire fresco a una industriar que estaba en claro declive. Casi 50 años más tarde, los 210 km/h inic...

  1. ALTAS CAPACIDADES: COMPARATIVA ENTRE EL MODELO ESPAÑOL Y BRITÁNICO

    OpenAIRE

    Rodríguez-Vázquez, María

    2012-01-01

    El presente trabajo de investigación exploratoria reflexiona sobre el concepto de alumno con altas capacidades y propone una comparación legislativa entre el modelo de atención a los alumnos con altas capacidades británico y español y cómo ese modelo afecta al sistema educativo general, ya que aunque tienen puntos en común entre ambos países, pero se trata dos formas de enfocar completamente distintas. Además también pretende recoger información sobre iniciativas y proyectos que reflejen l...

  2. Altas capacidades: Proyecto educativo para el aula de Educación Primaria

    OpenAIRE

    López-Presedo, Iria Flavia

    2015-01-01

    El presente TFG tiene como principal finalidad dar una respuesta educativa, eminentemente práctica, al alumnado de altas capacidades dentro del grupo-clase. En primer lugar, se han revisado las teorías de varios autores sobre las altas capacidades, los métodos de detección e intervención con este tipo de alumnado y, finalmente, se ha elaborado un proyecto en forma de programa de enriquecimiento curricular. Este proyecto se inscribe dentro de la Teoría de las inteligencias múltiples de Gard...

  3. Altas capacidades intelectuales : investigación y propuesta desde las inteligencias múltiples

    OpenAIRE

    Pulido Vinuesa, Salomé

    2015-01-01

    El presente trabajo trata sobre las altas capacidades, investigando sobre ello acerca de su historia y evolución, los diversos tipos existentes, sus características, su identificación, su evaluación, sus metodologías, entre otros. Además, se ha realizado un resumen de cómo es tratada esta necesidad educativa por las leyes, antiguas y en vigor. De igual modo, se trata la educación inclusiva, ya que es un tema que afecta a alumnos/as con altas capacidades. El programa de intervención en rel...

  4. Tension pneumoperitoneum complicated with tension pneumothorax in a patient with diaphragmatic eventration

    Science.gov (United States)

    Akoglu, Haldun; Coban, Erkan; Guneysel, Ozlem

    2012-01-01

    Tension pneumothorax complicating a pneumoperitoneum is a rare but known entity. However, all previously published articles report an air leak through defects in the diaphragm connecting the pneumoperitoneum and the pneumothorax. Here, the case of a 36-year-old man in whom the pneumoperitoneum acted like a tension pneumothorax because of a congenital eventration of the left diaphragm without penetration is presented. Emergency needle decompression of the abdomen was performed. A gastric ulcer that had passed through the diaphragm to the right lung was diagnosed intraoperatively. Unfortunately, the patient developed a ventricular fibrillation that remained resistant to all resuscitative efforts, and the patient died shortly afterwards. PMID:22604199

  5. How do mechanosensitive channels sense membrane tension?

    Science.gov (United States)

    Rasmussen, Tim

    2016-08-15

    Mechanosensitive (MS) channels provide protection against hypo-osmotic shock in bacteria whereas eukaryotic MS channels fulfil a multitude of important functions beside osmoregulation. Interactions with the membrane lipids are responsible for the sensing of mechanical force for most known MS channels. It emerged recently that not only prokaryotic, but also eukaryotic, MS channels are able to directly sense the tension in the membrane bilayer without any additional cofactor. If the membrane is solely viewed as a continuous medium with specific anisotropic physical properties, the sensitivity towards tension changes can be explained as result of the hydrophobic coupling between membrane and transmembrane (TM) regions of the channel. The increased cross-sectional area of the MS channel in the active conformation and elastic deformations of the membrane close to the channel have been described as important factors. However, recent studies suggest that molecular interactions of lipids with the channels could play an important role in mechanosensation. Pockets in between TM helices were identified in the MS channel of small conductance (MscS) and YnaI that are filled with lipids. Less lipids are present in the open state of MscS than the closed according to MD simulations. Thus it was suggested that exclusion of lipid fatty acyl chains from these pockets, as a consequence of increased tension, would trigger gating. Similarly, in the eukaryotic MS channel TRAAK it was found that a lipid chain blocks the conducting path in the closed state. The role of these specific lipid interactions in mechanosensation are highlighted in this review. PMID:27528747

  6. Surface tension of HFC refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Okada, M. [Tsukuba Coll. of Technology (Japan). Dept. of Mechanical Engineering; Shibata, T.; Sato, Y.; Higashi, Y. [Iwaki Meisei Univ. (Japan)

    1999-01-01

    The surface tension of refrigerant mixtures, i.e., R-410A (50 mass% R-32/50 mass% R-125), R-410B (45 mass% R-32/55 mass% R-125), R-407C (23 mass% R-32/25 mass% R-125/52 mass% R-134a), R-404A (44 mass% R-125/52 mass% R-143a/4 mass% R-134a), and R-507 (50 mass% R-125/50 mass% R-143a), has been measured and correlated in the present study. Although the first three mixtures are very important as promising replacements for R-22 in air-conditioners and heat-pumps and the last two are promising replacements for R-502, surface tension data for these mixtures were not previously available. The measurements were conducted under conditions of coexistence of the sample liquid and its saturated vapor in equilibrium. The differential capillary rise method (DCRM) was used, with two glass capillaries with inner radii of 0.3034 {+-} 0.0002 and 0.5717 {+-} 0.0002 mm. The temperature range covered was from 273 to 323 K, and the uncertainty of measurements for surface tensions and temperatures is estimated to be at most {+-} 0.2 mN {center_dot} m{sup {minus}1} and {+-} 20 mK, respectively. A mixing rule was selected for representing the temperature dependence of the resultant data. These data were successfully represented by a mixing rule using mass fraction based on the van der Waals correlation.

  7. Surface Tension Driven Convection Experiment Completed

    Science.gov (United States)

    Jacobson, Thomas P.; Sedlak, Deborah A.

    1997-01-01

    The Surface Tension Driven Convection Experiment (STDCE) was designed to study basic fluid mechanics and heat transfer on thermocapillary flows generated by temperature variations along the free surfaces of liquids in microgravity. STDCE first flew on the USML-1 mission in July 1992 and was rebuilt for the USML-2 mission that was launched in October 1995. This was a collaborative project with principal investigators from Case Western Reserve University (CWRU), Professors Simon Ostrach and Yasuhiro Kamotani, along with a team from the NASA Lewis Research Center composed of civil servants and contractors from Aerospace Design & Fabrication, Inc. (ADF), Analex, and NYMA, Inc.

  8. Normal-tension glaucoma: an update.

    Science.gov (United States)

    Esporcatte, Bruno Leonardo Barranco; Tavares, Ivan Maynart

    2016-01-01

    Normal-tension glaucoma (NTG) is a progressive optic neuropathy with intraocular pressure (IOP) within the statistically normal range (≤21 mmHg). The prevalence of NTG varies widely among different population studies, being the most prevalent open-angle glaucoma subtype in some reports. The etiology of NTG possibly is multifactorial and still not well defined. Alternative treatments have been proposed based on pathogenesis details. However, in clinical practice, adequate reduction of IOP remains the keystone of managing patients with NTG. We review the pathogenesis of NTG and the available therapies for this optic neuropathy. PMID:27626157

  9. Fatigue in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1999-01-01

    Traditinally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...... are made on dowel type connections that have tension perpendicular to the grain as limiting strength parameter. Is is concluded that no significant influence of duration of load is observed when the fatigue resistance of small specimens at 0.01 Hz and 0.1 Hz are compared. A weak but inconclusive time...

  10. OXYGEN TENSION REGULATES PREOSTEOCYTE MATURATION AND MINERALIZATION

    OpenAIRE

    Zahm, Adam; Bucaro, Michael; Srinivas, Vickram; Shapiro, Irving M.; Adams, Christopher S.

    2008-01-01

    The goal of this investigation was to test the hypothesis that low pO2 regulates bone cell mineralization. MLO-A5 and MLO-Y4 cells were cultured in monolayer and alginate scaffolds in hypoxia (2% O2) or normoxia (20% O2). Reduction of the O2 tension from 20% to 2% resulted in reduced mineralization and decreased alkaline phosphatase activity of MLO-A5 cells in both monolayer and three-dimensional cultures. Similar changes in osteogenic activity were seen when these preosteocyte-like cells wer...

  11. Interpreting expressive performance through listener judgments of musical tension

    Directory of Open Access Journals (Sweden)

    Morwaread Mary Farbood

    2013-12-01

    Full Text Available This study examines listener judgments of musical tension for a recording of a Schubert song and its harmonic reduction. Continuous tension ratings collected in an experiment and quantitative descriptions of the piece’s musical features, include dynamics, pitch height, harmony, onset frequency, and tempo, were analyzed from two different angles. In the first part of the analysis, the different processing timescales for disparate features contributing to tension were explored through the optimization of a predictive tension model. The results revealed the optimal time windows for harmony were considerably longer (~22 s than for any other feature (~1-4 s. In the second part of the analysis, tension ratings for the individual verses of the song and its harmonic reduction were examined and compared. The results showed that although the average tension ratings between verses were very similar, differences in how and when participants reported tension changes highlighted performance decisions made in the interpretation of the score, ambiguity in tension implications of the music, and the potential importance of contrast between verses and phrases. Analysis of the tension ratings for the harmonic reduction also provided a new perspective for better understanding how complex musical features inform listener tension judgments.

  12. Interpreting expressive performance through listener judgments of musical tension.

    Science.gov (United States)

    Farbood, Morwaread M; Upham, Finn

    2013-01-01

    This study examines listener judgments of musical tension for a recording of a Schubert song and its harmonic reduction. Continuous tension ratings collected in an experiment and quantitative descriptions of the piece's musical features, include dynamics, pitch height, harmony, onset frequency, and tempo, were analyzed from two different angles. In the first part of the analysis, the different processing timescales for disparate features contributing to tension were explored through the optimization of a predictive tension model. The results revealed the optimal time windows for harmony were considerably longer (~22 s) than for any other feature (~1-4 s). In the second part of the analysis, tension ratings for the individual verses of the song and its harmonic reduction were examined and compared. The results showed that although the average tension ratings between verses were very similar, differences in how and when participants reported tension changes highlighted performance decisions made in the interpretation of the score, ambiguity in tension implications of the music, and the potential importance of contrast between verses and phrases. Analysis of the tension ratings for the harmonic reduction also provided a new perspective for better understanding how complex musical features inform listener tension judgments. PMID:24416024

  13. Sistema de cómputo reconfigurable de alta performance (proyecto HPRC)

    OpenAIRE

    Kunysz, Eduardo; Rapallini, José Antonio; Osio, Jorge R.

    2015-01-01

    El objetivo de este trabajo es el estudio de las nuevas tendencias en cómputo paralelo con la finalidad de mejorar el rendimiento de cálculo. Cómo una alternativa interesante para optimizar la relación costo-prestaciones, se exploran tecnologías de computadoras de alta performance reconfigurable (HPCR).

  14. 77 FR 38823 - Notice of Availability of the Alta East Wind Project Draft Environmental Impact Statement...

    Science.gov (United States)

    2012-06-29

    ... Bureau of Land Management Notice of Availability of the Alta East Wind Project Draft Environmental Impact Statement/Environmental Impact Report and Proposed California Desert Conservation Area Plan Amendment, Kern... for future wind energy generation projects. The Draft EIS/EIR/PA evaluates the potential impacts...

  15. Grounding the past : the praxis of participatory archaeology in the Mixteca Alta, Oaxaca, Mexico

    NARCIS (Netherlands)

    Geurds, Alexander

    2007-01-01

    "Grounding the Past" addresses archaeological field praxis and its role in the political present of Santiago Tilantongo and Santiago Apoala, two communities in the Mixteca Alta region of Oaxaca, Mexico. Efforts to involve local stakeholder communities in archaeology have become an important issue wo

  16. La evaluación psicopedagógica del alumnado con altas capacidades

    OpenAIRE

    Grau Rubio, Claudia

    2012-01-01

    Se describen los instrumentos de evaluación psicopedagógica aplicables al alumnado con altas capacidades. Instrumentos referidos al alumno, al contexto escolar, a las variables socio-familiares y la determinación de las necesidades educativas especiales.

  17. 77 FR 23712 - Alta Wind VII, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Science.gov (United States)

    2012-04-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Alta Wind VII, LLC; Supplemental Notice That Initial Market-Based Rate...-referenced proceeding of Alta Wind VII, LLC's application for market-based rate authority, with...

  18. 77 FR 35669 - AltaGas Renewable Energy Colorado LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2012-06-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission AltaGas Renewable Energy Colorado LLC; Supplemental Notice That Initial... notice in the above-referenced proceeding of AltaGas Renewable Energy Colorado LLC application for...

  19. 76 FR 3881 - Application To Export Electric Energy; TransAlta Energy Marketing (U.S.) Inc.

    Science.gov (United States)

    2011-01-21

    ... Application To Export Electric Energy; TransAlta Energy Marketing (U.S.) Inc. AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of application. SUMMARY: TransAlta Energy Marketing (U... Office) 202-586-5260. SUPPLEMENTARY INFORMATION: Exports of electricity from the United States to...

  20. Tension-type headache: pain, fatigue, tension, and EMG responses to mental activation.

    Science.gov (United States)

    Bansevicius, D; Westgaard, R H; Sjaastad, O M

    1999-06-01

    Twenty patients with tension-type headache (14 chronic and 6 episodic) and 20 group-matched controls were selected for this study. They participated in a 1-hour, complex, two-choice, reaction-time test, as well as 5-minute pretest and 20-minute posttest periods. Subjects reported any pain in the forehead, temples, neck, and shoulders, as well as any feelings of fatigue and tension during the pretest, and every 10 minutes during the test and posttest by visual analog scales. Superficial electromyography was recorded simultaneously from positions representing the frontal and temporal muscles, neck (mostly splenius), and trapezius muscles. The location of pain corresponded to the position of the electrodes, but extended over a larger area. The test provoked pain in the forehead, neck, and shoulders of patients, i.e., pain scores from these regions increased significantly during the test. The pain scores continued to increase posttest. In patients, the EMG response of the trapezius (first 10 minutes of the test) was elevated relative to pretest. In controls, only the frontal muscles showed an EMG test response. Patients showed significantly higher EMG responses than controls in the neck (whole test period) and trapezius (first 10 minutes of the test period). There were significant differences in pain and fatigue scoring between patients and controls in all three periods and in tension scoring posttest. Fatigue correlated with pain, with increasing significance for all locations examined, while tension was mainly associated with the neck pain. The meaning of the variables "tension" and "fatigue" in headache, and their association with recorded muscle activity in various regions is discussed. The EMG response of the trapezius muscle to the test is discussed in comparison with similar responses observed in patients with other pain syndromes.

  1. Theoretical and experimental study on surface tension and dynamic surface tension of aqueous lithium bromide and water with additive

    Institute of Scientific and Technical Information of China (English)

    程文龙; 陈则韶; 秋泽淳; 胡芃; 柏木孝夫

    2003-01-01

    The surface tensions of water and aqueous lithium bromide (LiBr) with 2-ethyl-1-hexa- nol (2EH) and 1-octanol were measured using Wilhelmy plate method, and the oscillation of surface tension under the open condition for LiBr solution was observed. The dynamic surface tensions of water and LiBr solution in the presence of the 2EH and 1-octanol vapor were measured in this paper. The results showed that the additives vapor could obviously affect surface tension. For water, the dynamic surface tension was also affected by the mass of the tested liquid; however, for LiBr solution, the dynamic surface tension was not related to the mass of the tested solution. According to the experimental results, the hypothesis that surface tension varies linearly with the surface excess concentration is advanced, which could overcome the limit of Gibbs equation. The equations of surface absorption and desorption are modified, the units of the adsorption coefficient and desorption coefficient are unified; the effects of the liquid and vapor of additive on the surface tension are unified; the theoretical relations of the static surface tension and dynamic surface tension with the relative contents of the liquid and vapor of additive are obtained under the combined actions of them; the theoretical equations are validated by the experiments results.

  2. Influence of surface tension on two fluids shearing instability

    OpenAIRE

    Banerjee, Rahul; Kanjilal, S.

    2014-01-01

    Using extended Layzer's potential flow model, we investigate the effects of surface tension on the growth of the bubble and spike in combined Rayleigh-Taylor and Kelvin-Helmholtz instability. The nonlinear asymptotic solutions are obtained analytically for the velocity and curvature of the bubble and spike tip. We find that the surface tension decreases the velocity but does not affect the curvature, provided surface tension is greater than a critical value. For a certain condition, we observ...

  3. The free boundary Euler equations with large surface tension

    OpenAIRE

    Disconzi, Marcelo M.; Ebin, David G.

    2015-01-01

    We study the free boundary Euler equations with surface tension in three spatial dimensions, showing that the equations are well-posed if the coefficient of surface tension is positive. Then we prove that under natural assumptions, the solutions of the free boundary motion converge to solutions of the Euler equations in a domain with fixed boundary when the coefficient of surface tension tends to infinity.

  4. Surface tension in the dilute Ising model. The Wulff construction

    OpenAIRE

    Wouts, Marc

    2008-01-01

    We study the surface tension and the phenomenon of phase coexistence for the Ising model on $\\mathbbm{Z}^d$ ($d \\geqslant 2$) with ferromagnetic but random couplings. We prove the convergence in probability (with respect to random couplings) of surface tension and analyze its large deviations : upper deviations occur at volume order while lower deviations occur at surface order. We study the asymptotics of surface tension at low temperatures and relate the quenched value $\\tau^q$ of surface t...

  5. The free boundary Euler equations with large surface tension

    Science.gov (United States)

    Disconzi, Marcelo M.; Ebin, David G.

    2016-07-01

    We study the free boundary Euler equations with surface tension in three spatial dimensions, showing that the equations are well-posed if the coefficient of surface tension is positive. Then we prove that under natural assumptions, the solutions of the free boundary motion converge to solutions of the Euler equations in a domain with fixed boundary when the coefficient of surface tension tends to infinity.

  6. Surface tension of Nanofluid-type fuels containing suspended nanomaterials

    OpenAIRE

    Tanvir, Saad; Qiao, Li

    2012-01-01

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with partic...

  7. Surface tension with Normal Curvature in Curved Space-Time

    OpenAIRE

    Kumar, Himanshu; Alam, Sharf; Ahmad, Suhail

    2012-01-01

    With an aim to include the contribution of surface tension in the action of the boundary, we define the tangential pressure in terms of surface tension and Normal curvature in a more naturally geometric way. First, we show that the negative tangential pressure is independent of the four-velocity of a very thin hyper-surface. Second, we relate the 3-pressure of a surface layer to the normal curvature and the surface tension. Third, we relate the surface tension to the energy of the surface lay...

  8. The law of corresponding states and surface tension of metals

    International Nuclear Information System (INIS)

    Full Text: Surface tension of liquid metals is one of fundamental and most important quantities in theory and practice of material processing and its temperature dependence leads to the well-known Marangoni convection. Although currently methods are sufficiently precise to measure the surface tension, there are uncertainties in experimental data and its temperature dependence mainly due to impurity, which even a trace of it strongly affects the results of measurements. The theoretical treatment from the first principles is unwieldy and not always permits one to calculate the surface tension with certainty. Another active research field deals with empirical correlation between the surface tension and bulk thermodynamic properties, which we interpret as a simple consequence of the law of corresponding states. In order to relate the surface tension and to bulk properties of liquid metals the reduced formula is derived by scaling with the melting point Tm (0) at p = 0 and atomic volume Ω02/3 at T = 0 K as macroscopic parameters for scaling ε and a characterizing the interatomic potential in metals. The reduced surface tension and the reduced surface entropy obtained in high temperature limit are discussed and compared with the experiment. The reduced temperature coefficient of the surface tension found is a universal constant for the metals of the same structure. It is shown that pressure dependence of the surface tension, so called baric coefficient of the surface tension, can be described by pressure dependence of scaling parameters Tm (p) and Ω0 (p). (author)

  9. Size Effect for Normal Strength Concrete in Uniaxial Tension

    Institute of Scientific and Technical Information of China (English)

    李庆斌; 尹玉先

    2004-01-01

    This paper presents a new size effect model for normal strength concrete subjected to uniaxial tension. The model is based on two extremes, sand cement paste in uniaxial tension and a sand-cement-paste/rock interface in uniaxial tension. Uniaxial tension tests with normal strength concrete measuring the tensile strength of normal strength concrete specimens with different geometrical shapes and different ratios of the aggregate size to the characteristic dimension of the concrete specimen show a significant size effect. The theoretical size effect law prediction agrees well with the experimental data.

  10. Exploratory experimental investigations on post-tensioned structural glass beams

    DEFF Research Database (Denmark)

    Louter, C.; Nielsen, Jens Henrik; Belis, J.

    2013-01-01

    This paper discusses two projects on post-tensioned glass beams, performed at EPFL and DTU, respectively. In these projects small scale glass beams (length of 1.5m and 1m) are post-tensioned by means of steel threaded rods tensioned at the beam ends. The purpose of post-tensioning glass beams is ...... and promising concept, which provides enhanced strength and ductile (post-breakage) performance. Since the current investigations are exploratory, the investigated concepts leave unsolved challenges for future research within this field....

  11. Steady periodic gravity waves with surface tension

    CERN Document Server

    Walsh, Samuel

    2009-01-01

    In this paper we consider two-dimensional, stratified, steady water waves propagating over an impermeable flat bed and with a free surface. The motion is assumed to be driven by capillarity (that is, surface tension) on the surface and a gravitational force acting on the body of the fluid. We prove the existence of global continua of classical solutions that are periodic and traveling. This is accomplished by first constructing a 1-parameter family of laminar flow solutions, $\\mathcal{T}$, then applying bifurcation theory methods to obtain local curves of small amplitude solutions branching from $\\mathcal{T}$ at an eigenvalue of the linearized problem. Each solution curve is then continued globally by means of a degree theoretic theorem in the spirit of Rabinowitz. Finally, we complement the degree theoretic picture by proving an alternate global bifurcation theorem via the analytic continuation method of Dancer.

  12. The Curriculum. Conceptual and Practical Tensions

    Directory of Open Access Journals (Sweden)

    Ángel Díaz Barriga

    2003-11-01

    Full Text Available The purpose of this essay is to analyze the formation of two currents in the field of curriculum. These currents, over the last century, were visualized in different ways: one which considers the educational project as linked to a system or an educational institution, a perspective expressed in the various proposals to develop study plans and programs; the other, which links it with concepts like everyday life, curriculum as educational practice and curricular reality, which vindicate what is happening in the educational environment, particularly in the classroom. This paper recognizes a meeting of both currents in the origins of the curriculum field in the early twentieth century; at the same time we analyze its evolution marked by mutual discrediting and ignorance that have generated tensions. It reflects on the need to identify the limitations of each current, but also to recognize their successes.

  13. Neurotrophic factors in tension-type headache

    Directory of Open Access Journals (Sweden)

    Renan B. Domingues

    2015-05-01

    Full Text Available Neurotrophic factors (NF are involved in pain regulation and a few studies have suggested that they may play a pathophysiological role in primary headaches. The aim of this study was to investigate NF levels in patients with tension type headache (TTH. We carried out a cross sectional study including 48 TTH patients and 48 age and gender matched controls. Beck Depression and Anxiety Inventories, and Headache Impact Test were recorded. Serum levels of NF were determined by ELISA. There were not significant differences between NF levels between TTH patients and controls. Patients with chronic and episodic TTH had not significant differences in NF levels. The presence of headache at the time of evaluation did not significantly alter the levels of NF. Depression and anxiety scores as well as headache impact did not correlate with NF levels. Our study suggest that the serum levels of NF are not altered in TTH.

  14. Evolving spacetimes with purely radial tension

    Directory of Open Access Journals (Sweden)

    B. Nasre Esfahani

    2000-12-01

    Full Text Available   In this study time-dependent and spherically symmetric solutions of the Einstein field equations in an anisotropic background with a purely radial tension are presented. There exist three classes of solutions,1 An open spacetime with a wormhole at its center. 2 A conical spacetime. 3 A closed spacetime. These inhomogeneous solutions are reduced to FRW spacetimes in matter-dominated era, asymptotically. Therefore, they can be used to describe local inhomogeneities that are not considered in the standard model. For the wormhole solution. it is explicity shown that the considered matter is non-exotic, that is, it does not violate the energy conditions. Also, static solutions are studied. There is only one static solution,a conical spacetime. In this case, the matter satisfies the energy condition critically.

  15. Shell tension forces propel Dictyostelium slugs forward

    International Nuclear Information System (INIS)

    The Dictyostelium slug is an excellent model system for studying collective movements, as it is comprised of about 105 cells all moving together in the same direction. It still remains unclear how this movement occurs and what the physical mechanisms behind it are. By applying our recently developed 3D traction force microscopy, we propose a simple explanation for slug propulsion. Most of the forces are exerted by the sheath surrounding the slug. This secreted shell is under a rather uniform tension (around 50 mN m−1) and will give rise to a tissue under pressure. Finally, we propose that this pressure will naturally push the slug tip forwards if a gradient of shell mechanical properties takes place in the very anterior part of the raised tip. (paper)

  16. Shell tension forces propel Dictyostelium slugs forward.

    Science.gov (United States)

    Rieu, Jean-Paul; Delanoë-Ayari, Hélène

    2012-12-01

    The Dictyostelium slug is an excellent model system for studying collective movements, as it is comprised of about 10(5) cells all moving together in the same direction. It still remains unclear how this movement occurs and what the physical mechanisms behind it are. By applying our recently developed 3D traction force microscopy, we propose a simple explanation for slug propulsion. Most of the forces are exerted by the sheath surrounding the slug. This secreted shell is under a rather uniform tension (around 50 mN m(-1)) and will give rise to a tissue under pressure. Finally, we propose that this pressure will naturally push the slug tip forwards if a gradient of shell mechanical properties takes place in the very anterior part of the raised tip.

  17. Biaxial tension on polymer in thermoforming range

    Directory of Open Access Journals (Sweden)

    Billon N.

    2010-06-01

    Full Text Available This paper presents an experimental characterization of mechanical properties of a polyethylene terephtalate (PET resin classically used in stretch blow moulding process. We have applied on such a material a well established experimental protocol at CEMEF, including new and relevant biaxial tensile tests. The experimental set-up relative to biaxial tension will be presented and described in a first part of the paper. Furthermore, we will focus on the experimental DMTA preliminary tests which are required to estimate the resin sensibility to temperature and strain rate in linear viscoelasticity domain. Finally, we will be interested in the material large strain behaviour: biaxial tensile results are presented and discussed. Finally, such an experimental approach should allow a relevant modelling of polymer physics and mechanics; this point will not be discussed here because of a lack of time.

  18. Biaxial tension on polymer in thermoforming range

    Science.gov (United States)

    Becker, S.; Combeaud, C.; Fournier, F.; Rodriguez, J.; Billon, N.

    2010-06-01

    This paper presents an experimental characterization of mechanical properties of a polyethylene terephtalate (PET) resin classically used in stretch blow moulding process. We have applied on such a material a well established experimental protocol at CEMEF, including new and relevant biaxial tensile tests. The experimental set-up relative to biaxial tension will be presented and described in a first part of the paper. Furthermore, we will focus on the experimental DMTA preliminary tests which are required to estimate the resin sensibility to temperature and strain rate in linear viscoelasticity domain. Finally, we will be interested in the material large strain behaviour: biaxial tensile results are presented and discussed. Finally, such an experimental approach should allow a relevant modelling of polymer physics and mechanics; this point will not be discussed here because of a lack of time.

  19. Modifying horizon thermodynamics by surface tensions

    CERN Document Server

    Chen, Deyou

    2016-01-01

    The modified first laws of thermodynamics at the black hole horizon and the cosmological horizon of the Schwarzschild de Sitter black hole and the apparent horizon of the Friedmann-Robertson-Walker cosmology are derived by the surface tensions, respectively. The corresponding Smarr relations are obeyed. For the black hole, the cosmological constant is first treated as a fixed constant, and then as a variable associated to the pressure. The law at the apparent horizon takes the same form as that at the cosmological horizon, but is different from that at the black hole horizon. The positive temperatures guarantee the appearance of the worked terms in the modified laws at the cosmological and apparent horizons. While they can disappear at the black hole horizon.

  20. Membrane tension regulates clathrin-coated pit dynamics

    Science.gov (United States)

    Liu, Allen

    2014-03-01

    Intracellular organization depends on close communication between the extracellular environment and a network of cytoskeleton filaments. The interactions between cytoskeletal filaments and the plasma membrane lead to changes in membrane tension that in turns help regulate biological processes. Endocytosis is thought to be stimulated by low membrane tension and the removal of membrane increases membrane tension. While it is appreciated that the opposing effects of exocytosis and endocytosis have on keeping plasma membrane tension to a set point, it is not clear how membrane tension affects the dynamics of clathrin-coated pits (CCPs), the individual functional units of clathrin-mediated endocytosis. Furthermore, although it was recently shown that actin dynamics counteracts membrane tension during CCP formation, it is not clear what roles plasma membrane tension plays during CCP initiation. Based on the notion that plasma membrane tension is increased when the membrane area increases during cell spreading, we designed micro-patterned surfaces of different sizes to control the cell spreading sizes. Total internal reflection fluorescence microscopy of living cells and high content image analysis were used to quantify the dynamics of CCPs. We found that there is an increased proportion of CCPs with short (<20s) lifetime for cells on larger patterns. Interestingly, cells on larger patterns have higher CCP initiation density, an effect unexpected based on the conventional view of decreasing endocytosis with increasing membrane tension. Furthermore, by analyzing the intensity profiles of CCPs that were longer-lived, we found CCP intensity decreases with increasing cell size, indicating that the CCPs are smaller with increasing membrane tension. Finally, disruption of actin dynamics significantly increased the number of short-lived CCPs, but also decreased CCP initiation rate. Together, our study reveals new mechanistic insights into how plasma membrane tension regulates

  1. Mechanical evaluation of anastomotic tension and patency in arteries.

    Science.gov (United States)

    Zhang, F; Lineaweaver, W C; Buntic, R; Walker, R

    1996-02-01

    This study quantified arterial anastomotic tension, evaluated subsequent patency rates, and examined the degree of tension reduction with vessel mobilization. The study was divided into two components. In part I, a mechanical analysis was undertaken to evaluate tension, based on the determination of the force required to deflect a cable (vessel) laterally, and its resulting lateral displacement. Six Sprague-Dawley rats with 12 femoral arteries were divided into two subgroups: 1) no mobilization; and 2) axial mobilization by ligation and transection of superficial epigastric and gracilis muscular branches. The tension of femoral arterial anastomoses was calculated in vessels with no segmental defect and with 1.5-, 3-, 4.5-, 6-, and 7.5-mm defects. In part II, patency was evaluated. Fifty-five rats with 110 femoral arteries were divided into two sub-groups as defined in part I: 1) no mobilization; and 2) axial mobilization by ligation and transection of superficial epigastric and gracilis muscular branches. Microvascular anastomoses were performed with no segmental defect and with 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, and 10-mm segmental vessel defects. Patency was evaluated 24 hr postoperatively. Part I of the study revealed that anastomotic tension gradually increased along with an increase in the length of the vessel defect, from 1.9 to 11.34 g in the no-mobilization group and from 1.97 to 8.44 g in the axial-mobilization group. Comparison of tension linear regression coefficient showed a significant difference between the two groups (p tension approximately 6 g) in the no-mobilization group and 6 mm in the axial-mobilization group (tension approximately 6.48 g). Microanastomotic tension was related to the size of the vessel defect, with increasing tension leading to thrombosis. Axial mobilization significantly reduced the tension in vessels with segmental defects and decreased thrombosis rates.

  2. Necessary Tension in Marine Risers (Continued Tension des colonnes montantes en mer (suite

    Directory of Open Access Journals (Sweden)

    Lubinski A.

    2006-11-01

    Full Text Available A simple, first approximation method for calculating the necessary tension in a marine riser, is presented. This article is a practical supplement ta the one published under the same title in the March-April 1977 issue of Revue de l'Institut Français du Pétrole. On présente dans cet article une méthode simple permettant de calculer en première approximation la tension d'une colonne montante en mer. Cet article est le complément pratique de celui publié sous le même titre dans le numéro mars-avril 1977 de la Revue de l'Institut Français du Pétrole.

  3. Negotiating Narrative Inquiries: Living in a Tension-Filled Midst

    Science.gov (United States)

    Clandinin, D. Jean; Murphy, M. Shaun; Huber, Janice; Orr, Anne Murray

    2010-01-01

    The authors explore the place of tension in understanding narrative inquiry as a relational research methodology. Drawing on a narrative inquiry into children's, teachers', and families' experiences in schools shaped by achievement testing practices that flow from accountability policies, the authors show how attending to tensions is central to…

  4. Classical solutions for Hele-Shaw models with surface tension

    OpenAIRE

    Escher, Joachim; Simonett, Gieri

    1997-01-01

    It is shown that surface tension effects on the free boundary are regularizing for Hele-Shaw models. This implies, in particular, existence and uniqueness of classical solutions for a large class of initial data. As a consequence, we give a rigorous proof of the fact that homogeneous Hele-Shaw flows with positive surface tension are volume preserving and area shrinking.

  5. Pendant-Drop Surface-Tension Measurement On Molten Metal

    Science.gov (United States)

    Man, Kin Fung; Thiessen, David

    1996-01-01

    Method of measuring surface tension of molten metal based on pendant-drop method implemented in quasi-containerless manner and augmented with digital processing of image data. Electrons bombard lower end of sample rod in vacuum, generating hanging drop of molten metal. Surface tension of drop computed from its shape. Technique minimizes effects of contamination.

  6. Thermodynamics of surface tension: application to electrolyte solution

    OpenAIRE

    Levin, Yan

    2001-01-01

    In this contribution to the special issue of the Journal of Statistical Physics dedicated to Michael Fisher on his 70'th birthday, I shall review two thermodynamically distinct routes for obtaining the interfacial tension of liquid-vapor interfaces in mixtures. A specific application to the calculation of the excess surface tension of aqueous electrolyte solutions will be presented.

  7. Surface tension and long range corrections of cylindrical interfaces

    International Nuclear Information System (INIS)

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials

  8. The Cartesian Diver, Surface Tension and the Cheerios Effect

    Science.gov (United States)

    Chen, Chi-Tung; Lee, Wen-Tang; Kao, Sung-Kai

    2014-01-01

    A Cartesian diver can be used to measure the surface tension of a liquid to a certain extent. The surface tension measurement is related to the two critical pressures at which the diver is about to sink and about to emerge. After sinking because of increasing pressure, the diver is repulsed to the centre of the vessel. After the pressure is…

  9. Bending Under Tension Test with Direct Friction Measurement

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Olsson, David Dam; Chodnikiewicz, K.;

    2006-01-01

    A special Bending-Under-Tension (BUT) transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all meas...... in drawing of stainless steel showing the influence of varying process conditions and the performance of different lubricants.......A special Bending-Under-Tension (BUT) transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all...... measured directly, thus enabling accurate measurement of friction and direct determination of lubricant film breakdown for varying normal pressure, sliding speed, tool radius and tool preheat temperature. The transducer is applied in an experimental investigation focusing on limits of lubrication...

  10. Dorzolamide increases retinal oxygen tension after branch retinal vein occlusion

    DEFF Research Database (Denmark)

    Noergaard, Michael Hove; Bach-Holm, Daniella; Scherfig, Erik;

    2008-01-01

    To study the effect of dorzolamide on the preretinal oxygen tension (RPO(2)) in retinal areas affected by experimental branch retinal vein occlusion (BRVO) in pigs.......To study the effect of dorzolamide on the preretinal oxygen tension (RPO(2)) in retinal areas affected by experimental branch retinal vein occlusion (BRVO) in pigs....

  11. Managing Tensions Between New and Existing Business Models

    DEFF Research Database (Denmark)

    Sund, Kristian J.; Bogers, Marcel; Villarroel, J. Andrei;

    2016-01-01

    The search for new business models forces established companies to experiment with organizational designs — and leads to tensions that should be anticipated and carefully managed.......The search for new business models forces established companies to experiment with organizational designs — and leads to tensions that should be anticipated and carefully managed....

  12. Note About Unstable D-Brane with Dynamical Tension

    CERN Document Server

    Kluson, J

    2016-01-01

    We propose an action for unstable Dp-brane with dynamical tension. We show that the equations of motion are equivalent to the equations of motion derived from DBI and WZ actions for non-BPS Dp-brane. We also find Hamiltonian formulation of this action and analyze properties of the solutions corresponding to the tachyon vacuum and zero tension solution.

  13. Rapid cable tension estimation using dynamic and mechanical properties

    Science.gov (United States)

    Martínez-Castro, Rosana E.; Jang, Shinae; Christenson, Richard E.

    2016-04-01

    Main tension elements are critical to the overall stability of cable-supported bridges. A dependable and rapid determination of cable tension is desired to assess the state of a cable-supported bridge and evaluate its operability. A portable smart sensor setup is presented to reduce post-processing time and deployment complexity while reliably determining cable tension using dynamic characteristics extracted from spectral analysis. A self-recording accelerometer is coupled with a single-board microcomputer that communicates wirelessly with a remote host computer. The portable smart sensing device is designed such that additional algorithms, sensors and controlling devices for various monitoring applications can be installed and operated for additional structural assessment. The tension-estimating algorithms are based on taut string theory and expand to consider bending stiffness. The successful combination of cable properties allows the use of a cable's dynamic behavior to determine tension force. The tension-estimating algorithms are experimentally validated on a through-arch steel bridge subject to ambient vibration induced by passing traffic. The tension estimation is determined in well agreement with previously determined tension values for the structure.

  14. Tensions in the Biology Laboratory: What Are They?

    Science.gov (United States)

    Tan, Aik-Ling

    2008-01-01

    The purpose of this paper is to identify tensions in teacher-student interaction in a high school biology laboratory. Using micro-analytic analysis of classroom talk, the interaction between the students and a teacher working in the biology laboratory session on "Reproduction in Plants" is studied. The two tensions highlighted here are tension…

  15. On innovation patterns and value-tensions in public services

    DEFF Research Database (Denmark)

    Fuglsang, Lars; Rønning, Rolf

    2015-01-01

    to the possibility of intertwined innovation patterns. Focusing public sector services, this paper agues that intertwined innovation patterns emerge within public services as a response to value-tensions. Values can be defined as measures for beneficial behaviour that guide innovation. Value-tensions in public...

  16. Surface tension and long range corrections of cylindrical interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bourasseau, E. [CEA/DAM DIF, F-91297 Arpajon Cedex (France); Malfreyt, P. [Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Ghoufi, A., E-mail: aziz.ghoufi@univ-rennes1.fr [Institut de Physique de Rennes, UMR 6251 CNRS, Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes (France)

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  17. Conducting Qualitative Data Analysis: Managing Dynamic Tensions within

    Science.gov (United States)

    Chenail, Ronald J.

    2012-01-01

    In the third of a series of "how-to" essays on conducting qualitative data analysis, Ron Chenail examines the dynamic tensions within the process of qualitative data analysis that qualitative researchers must manage in order to produce credible and creative results. These tensions include (a) the qualities of the data and the qualitative data…

  18. Managing Tensions Between New and Existing Business Models

    DEFF Research Database (Denmark)

    Sund, Kristian J.; Bogers, Marcel; Villarroel Fernandez, Juan Andrei;

    2016-01-01

    Exploring new business models may be a good way to stay competitive, but doing so can create tensions internally, in areas such as organizational structure and competition for resources. Companies exploring business model innovation may not recognize the inevitability of these tensions and thus b...

  19. Black string corrections in variable tension braneworld scenarios

    CERN Document Server

    da Rocha, Roldao

    2012-01-01

    Braneworld models with variable tension are investigated, and the corrections on the black string horizon along the extra dimension are provided. Such corrections are encrypted in additional terms involving the covariant derivatives of the variable tension on the brane, providing profound consequences concerning the black string horizon variation along the extra dimension, near the brane. The black string horizon behavior is shown to be drastically modified by the terms corrected by the brane variable tension. In particular, a model motivated by the phenomenological interesting case regarding Eotvos branes is investigated. It forthwith provides further physical features regarding variable tension braneworld scenarios, heretofore concealed in all previous analysis in the literature. All precedent analysis considered uniquely the expansion of the metric up to the second order along the extra dimension, what is able to evince solely the brane variable tension absolute value. Notwithstanding, the expansion terms ...

  20. Maximum sustainable xylem sap tensions in Rhododendron and other species.

    Science.gov (United States)

    Crombie, D S; Milburn, J A; Hipkins, M F

    1985-01-01

    The acoustic technique was used in conjunction with the pressure chamber to determine the tensions causing cavitation of xylem sap in leaves of five woody angiosperms (Acer pseudoplatanus L., Alnus glutinosa L. Gaertn., Eucalyptus globulus Labill., Fraxinus excelsior L. and Rhododendron ponticum L.) and three species of herbs (Lycopersicum esculentum Mill., Plantago major L. and Ricinus communis L.). The results showed leaves of most species to suffer considerably from cavitation at sap tensions of 1.6-3 MPa. Two of the herbs, Lycopersicum and Ricinus, cavitated extensively at sap tensions below 1 MPa. Additional evidence is presented that clicks, detected by acoustic amplification, are caused by cavitation of sap in the xylem conduits. A rapid method is suggested for the determination of sap tensions in cavitating leaves and which is suitable for surveys of the critical sap tension in a large number of species.

  1. Design of tension control system for fiber placement equipments

    Directory of Open Access Journals (Sweden)

    Hongjie CHANG

    2015-10-01

    Full Text Available Aiming at the tension control requirements of automatic fiber placement equipments and the problems of traditional tension control system, the hammer tension control system is designed. The hammer is used as a buffer unit in the system, and the tension can be indirectly controlled by the position of the hammer. The system adopts the motion controller as the core element of the system, the AC servo motor as the actuator and the laser position sensor as the detector. The fuzzy PID control algorithm is used for the position control of hammer, which can avoid tension fluctuation by full consideration of the acceleration of the hammer. Prototype experimental results show that this system can avoid the problems of disconnection and relaxation of fiber, meanwhile, the static difference ratio and fluctuation ratio can meet the requirements of engineering practice.

  2. Exploratory experimental investigations on post-tensioned structural glass beams

    Directory of Open Access Journals (Sweden)

    Christian Louter

    2015-05-01

    Full Text Available The mechanical response of post-tensioned glass beams is explored in this paper. This is done through bending experiments on post-tensioned glass beam specimens with either mechanically anchored or adhesively bonded steel tendons by which a beneficial pre-stress is inflicted on the glass beams. In addition, reference beams with identical geometry but without tendons are tested. From the results of the bending experiments it can be seen that the post-tensioned glass beams reach higher initial fracture loads than the reference glass beams. Furthermore, the post-tensioned glass beams develop a significant post-fracture reserve. From this it is concluded that post-tensioning a glass beam is a feasible concept, which provides increased initial fracture strength and enhanced post-fracture performance.

  3. Surface tension of molten tin investigated with sessile drop method

    Institute of Scientific and Technical Information of China (English)

    LI Jing; YUAN Zhang-fu; FAN Jian-feng; KE Jia-jun

    2005-01-01

    The surface tension of molten tin was determined by a set of self-developed digital equipment with sessile drop method at oxygen partial pressure of 1.0 × 10-6 MPa under different temperatures, and the dependence of surface tension of molten tin on temperature was also discussed. The emphasis was placed on the comparison of surface tension of the same molten tin sample measured by using different equipments with sessile drop method. Results of the comparison indicate that the measurement results with sessile drop method under the approximate experimental conditions are coincident, and the self-developed digital equipment for surface tension measurement has higher stability and accuracy. The relationships of surface tension of molten tin and its temperature coefficient with temperature and oxygen partial pressure were also elucidated from the thermodynamic equilibrium analysis.

  4. Flexor digitorum profundus tendon tension during finger manipulation.

    Science.gov (United States)

    Tanaka, Tatsuro; Amadio, Peter C; Zhao, Chunfeng; Zobitz, Mark E; An, Kai-Nan

    2005-01-01

    Abstract The purpose of this study was to measure the tension in the flexor digitorum profundus (FDP) tendon in zone II and the digit angle during joint manipulations that replicate rehabilitation protocols. Eight FDP tendons from eight human cadavers were used in this study. The dynamic tension in zone II of the tendon and metacarpophalangeal (MCP) joint angle were measured in various wrist and digit positions. Tension in the FDP tendon increased with MCP joint extension. There was no tension with the finger fully flexed and wrist extended (synergistic motion), but the tendon force reached 1.77 +/- 0.43 N with the MCP joint hyperextended 45 degrees with the distal interphalangeal and proximal interphalangeal joints flexed. The combination of wrist extension and MCP joint hyperextension with the distal interphalangeal and proximal interphalangeal joints fully flexed, what the authors term "modified synergistic motion," produced a modest tendon tension and may be a useful alternative configuration to normal synergistic motion in tendon rehabilitation.

  5. Procesos de automatización cognitiva en alumnado con altas capacidades intelectuales

    Directory of Open Access Journals (Sweden)

    Juan Montero-Linares

    2013-05-01

    Full Text Available Proponemos desde el enfoque del procesamiento de la información, el estudio de características cognitivas que faciliten la identificación de las altas capacidades. A tal fin, elaboramos una tarea de habilidad de segmentación silábica que, a partir del modelo propuesto por Baddeley sobre la memoria de trabajo y la distinción entre procesos automáticos y controlados, nos permitiese comprobar las diferencias en cuanto a la capacidad de automatización de la información y si los indicadores propuestos en la misma, tenían suficiente poder clasificatorio o predictivo en la identificación de la alta capacidad intelectual. Participaron 480 niños y niñas de primero a cuarto de Educación Primaria. Se clasificaron, en función de su CI, en dos grupos: alumnado de altas capacidades y alumnado de capacidades medias. Se les administró una batería de pruebas entre las que se encontraba el test de habilidad de segmentación silábica, lo que permitió realizar su estandarización. Los resultados mostraron que los alumnos con CI superior a 130 fueron capaces de automatizar la segmentación de forma más eficiente que los de inteligencia media. La medición de los procesos automáticos a través del test de habilidad de segmentación silábica, permitió diferenciar a los participantes de altas capacidades de los que no lo eran.

  6. Compressão medular alta por cisto neuroentérico: relato de caso

    Directory of Open Access Journals (Sweden)

    Geraldo Pianettt Filho

    1993-06-01

    Full Text Available É relatado o caso raro de uma criança com cisto neuroentérico comprimindo a medula cervical alta de C1 a C3. A paciente foi submetida a laminectomia osteoplástica com retirada total do tumor. São discutidos a sintomatologia, o tratamento e o resultado satisfatório obtido. É feita revisão da literatura pertinente.

  7. Vital Signs – Presión arterial alta (High Blood Pressure)

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    En los EE. UU. casi un tercio de la población adulta tiene presión arterial alta, el principal factor de riesgo de enfermedades cardiacas y accidentes cerebrovasculares, dos de las principales causas de muerte en el país.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  8. Inbreeding incidence on biological fitness in an isolated Mediterranean population: La Alta Alpujarra Oriental (Southeastern Spain)

    OpenAIRE

    Luna, Francisco; Valls, A.; Fernández Santander, Ana

    1998-01-01

    The incidence of parental inbreeding on biological fitness was analysed in a sample of the Alpujarrenian population. Fitness was estimated as the fertility and offspring viability from conception to reproductive age. The analysed sample represents about 45% of the population from the Alta Alpujarra Oriental in southeastern Spain, and includes 847 families and 2916 pregnancies. The results showed slightly higher reproduction in consanguineous marriages, but the differences observed were not st...

  9. Altas habilidades: uma questão escolar Giftedness: a shool matter

    Directory of Open Access Journals (Sweden)

    Célia Maria Paz Ferreira Barreto

    2011-12-01

    Full Text Available Esse estudo foi realizado em uma escola federal de ensino, localizada no Rio de Janeiro. Estabeleceu como objetivos gerais investigar as representações dos professores sobre as altas habilidades e a existência da indicação de alunos com esse perfil para atendimento. Utilizou duas amostras diferenciadas. A primeira, formada por 36 professores que atuavam do 1º ao 9º ano do ensino fundamental e do 1º ao 3º ano do ensino médio. A outra amostra foi constituída por quatro setores da escola responsáveis pelo registro histórico dos alunos. Utilizou-se a metodologia da análise de conteúdo no tratamento dos dados obtidos. Os resultados mostraram que os professores respondentes têm representações sobre altas habilidades e que não existem alunos com altas habilidades matriculados na instituição. Os resultados indicam urgência no implemento de ações inclusivas para as altas habilidades nessa escola, assim como a continuidade e aprofundamento nessa pesquisa.The study took place in a public federal school in Rio de Janeiro. The overall objectives were to investigate representations teachers have about giftedness and existing indications of such students that should be referred to specific learning and counseling programs. Two different groups were taken as samples. The first was made up of 36 elementary and high school teachers. The other consisted of four school sectors, charged with keeping students data records. The qualitative method of contents analysis was used. This study indicates its participants have representations about giftedness, although there were no gifted students enrolled in the institution where the study took place. The results also suggest that there is a pressing need to implement inclusive actions for gifted students at this school, as well as further developing the investigation at a deeper level.

  10. USO DA INTERNET: DIFERENÇAS ENTRE CLASSE MÉDIA E ALTA

    Directory of Open Access Journals (Sweden)

    Jorge Ferreira da Silva

    2013-12-01

    Full Text Available Este estudo busca propor e testar um modelo que explique o uso da internet pelos jovens e identificar possíveis diferenças neste uso entre jovens de classe média e alta. A motivação para a pesquisa partiu da observação dos novos hábitos de consumo originados do uso da internet por estes jovens, que consideram a tecnologia indispensável em suas vidas. Baseado na literatura, o modelo final envolveu os seguintes fatores: Barreiras Percebidas ao Acesso, Comunicação, Interatividade e Uso da Internet. As hipóteses de pesquisa foram testadas por meio de uma survey com 394 jovens, com a amostra sendo divida em dois grupos: jovens de classe média e jovens de classe alta. Os dados foram analisados por modelagem de equações estruturais multigrupo. Os resultados sugerem diferenças na utilização de internet entre jovens de classe média e alta, com somente a classe média sendo influenciada significativamente pela Interatividade e Comunicação percebidas.

  11. Characterization of optimal resting tension in human pulmonary arteries

    Science.gov (United States)

    Hussain, Azar; Bennett, Robert T; Chaudhry, Mubarak A; Qadri, Syed S; Cowen, Mike; Morice, Alyn H; Loubani, Mahmoud

    2016-01-01

    AIM To determine the optimum resting tension (ORT) for in vitro human pulmonary artery (PA) ring preparations. METHODS Pulmonary arteries were dissected from disease free sections of the resected lung in the operating theatre and tissue samples were directly sent to the laboratory in Krebs-Henseleit solution (Krebs). The pulmonary arteries were then cut into 2 mm long rings. PA rings were mounted in 25 mL organ baths or 8 mL myograph chambers containing Krebs compound (37 °C, bubbled with 21% O2: 5% CO2) to measure changes in isometric tension. The resting tension was set at 1-gram force (gf) with vessels being left static to equilibrate for duration of one hour. Baseline contractile reactions to 40 mmol/L KCl were obtained from a resting tension of 1 gf. Contractile reactions to 40 mmol/L KCl were then obtained from stepwise increases in resting tension (1.2, 1.4, 1.6, 1.8 and 2.0 gf). RESULTS Twenty PA rings of internal diameter between 2-4 mm were prepared from 4 patients. In human PA rings incrementing the tension during rest stance by 0.6 gf, up to 1.6 gf significantly augmented the 40 mmol/L KCl stimulated tension. Further enhancement of active tension by 0.4 gf, up to 2.0 gf mitigate the 40 mmol/L KCl stimulated reaction. Both Myograph and the organ bath demonstrated identical conclusions, supporting that the radial optimal resting tension for human PA ring was 1.61 g. CONCLUSION The radial optimal resting tension in our experiment is 1.61 gf (15.78 mN) for human PA rings. PMID:27721938

  12. BIOFEEDBACK TRAINING AND TENSION-TYPE HEADACHE.

    Science.gov (United States)

    Šecić, Ana; Cvjeticanin, Timon; Kes, Vanja Bašić

    2016-03-01

    Biofeedback is a training method, which connects physiological and psychological processes in a person for the purposes of improving his/her physical, emotional, mental and spiritual health. In biofeedback treatment, an active role of the patient is stressed for him/her to be able to actively control the physiological and emotional processes. The aim of biofeedback is to improve the conscious control of the individual's involuntary physiological activity. Research has shown that biofeedback, either applied alone or in combination with other behavioral therapies (techniques), is an effective treatment for various medical and psychological disorders, from headache and hypertension to temporomandibular and attention deficit disorders. More than 90% of adults experience headache once a year, which makes headache one of the most common symptoms and diagnoses in medicine. Tension-type headaches occur in at least 40% of the population and their impact on the health insurance costs and diminished productivity is significant. Studies have shown that clinical biofeedback training is effective in treating headaches. Moreover, the authors stress the need for additional research and further development of methodology for this kind of research.

  13. Surface Tension Driven Convection Experiment (STDCE)

    Science.gov (United States)

    Ostrach, S.; Kamotani, Y.

    1996-01-01

    This document reports the results obtained from the Surface Tension Driven Convection Experiment (STDCE) conducted aboard the USML-1 Spacelab in 1992. The experiments used 10 cSt silicone oil placed in an open circular container that was 10 cm wide and 5 cm deep. Thermocapillary flow was induced by using either a cylindrical heater placed along the container centerline or by a CO2 laser. The tests were conducted under various power settings, laser beam diameters, and free surface shapes. Thermistors located at various positions in the test section recorded the temperature of the fluid, heater, walls, and air. An infrared imager was used to measure the free surface temperature. The flow field was studied by flow visualization and the data was analyzed by a PTV technique. The results from the flow visualization and the temperature measurements are compared with the numerical analysis that was conducted in conjunction with the experiment. The compared results include the experimental and numerical velocity vector plots, the streamline plots, the fluid temperature, and the surface temperature distribution.

  14. Ice Accretion with Varying Surface Tension

    Science.gov (United States)

    Bilanin, Alan J.; Anderson, David N.

    1995-01-01

    During an icing encounter of an aircraft in flight, super-cooled water droplets impinging on an airfoil may splash before freezing. This paper reports tests performed to determine if this effect is significant and uses the results to develop an improved scaling method for use in icing test facilities. Simple laboratory tests showed that drops splash on impact at the Reynolds and Weber numbers typical of icing encounters. Further confirmation of droplet splash came from icing tests performed in the NaSA Lewis Icing Research Tunnel (IRT) with a surfactant added to the spray water to reduce the surface tension. The resulting ice shapes were significantly different from those formed when no surfactant was added to the water. These results suggested that the droplet Weber number must be kept constant to properly scale icing test conditions. Finally, the paper presents a Weber-number-based scaling method and reports results from scaling tests in the IRT in which model size was reduced up to a factor of 3. Scale and reference ice shapes are shown which confirm the effectiveness of this new scaling method.

  15. Tension free femoral hernia repair with plug

    Institute of Scientific and Technical Information of China (English)

    Milivoje Vukovi; Neboja Moljevi; Sinia Crnogorac

    2013-01-01

    Objective: To investigate the conventional technique involves treatment of femoral hernia an approximation inguinal ligament to pectineal ligament. In technique which uses mesh closure for femoral canal without tissue tension. Method: A prospective study from January 01. 2007-May 30. 2009. We analyzed 1 042 patients with inguinal hernia, of which there were 83 patients with 86 femoral hernia. Result: Femoral hernias were present in 7.96% of cases. Males were 13 (15.66%) and 70 women (84.34%). The gender distribution of men: women is 1:5.38. Urgent underwent 69 (83%), and the 14 election (17%) patients. Average age was 63 years, the youngest patient was a 24 and the oldest 86 years. Ratio of right: left hernias was 3.4:1. With bilateral femoral hernias was 3.61% of cases. In 7 patients (8.43%) underwent femoral hernia repair with 9 Prolene plug. Conclusions: The technique of closing the femoral canal with plug a simple. The plug is made from monofilament material and is easily formed. This technique allows the reduction of recurrence and can be used safely, quickly and easily in elective and emergency situations.

  16. Ethnography in community psychology: promises and tensions.

    Science.gov (United States)

    Case, Andrew D; Todd, Nathan R; Kral, Michael J

    2014-09-01

    Community psychology recognizes the need for research methods that illuminate context, culture, diversity, and process. One such method, ethnography, has crossed into multiple disciplines from anthropology, and indeed, community psychologists are becoming community ethnographers. Ethnographic work stands at the intersection of bridging universal questions with the particularities of people and groups bounded in time, geographic location, and social location. Ethnography is thus historical and deeply contextual, enabling a rich, in-depth understanding of communities that is aligned with the values and goals of community psychology. The purpose of this paper is to elucidate the potential of ethnography for community psychology and to encourage its use within the field as a method to capture culture and context, to document process, and to reveal how social change and action occur within and through communities. We discuss the method of ethnography, draw connections to community psychology values and goals, and identify tensions from our experiences doing ethnography. Overall, we assert that ethnography is a method that resonates with community psychology and present this paper as a resource for those interested in using this method in their research or community activism.

  17. Ocular Blood Flow and Normal Tension Glaucoma

    Directory of Open Access Journals (Sweden)

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  18. Anestesia espinal alta para mastoplastia reductora. Experiencia de tres años

    Directory of Open Access Journals (Sweden)

    Néstor Parets Correa

    2012-05-01

    Full Text Available Fundamento: la aplicación de anestesia neuroaxial espinal alta en las intervenciones quirúrgicas resulta un tema controversial. Objetivo: describir los resultados de la aplicación de anestesia neuroaxial espinal alta en intervenciones quirúrgicas para mastoplastia reductora. Métodos: estudio descriptivo realizado en el Hospital General Universitario Dr. Gustavo Aldereguía Lima, de Cienfuegos, desde junio de 2006 hasta junio de 2009, que incluyó 90 pacientes operadas, en las cuales se empleó anestesia neuroaxial espinal alta. Se analizaron las variables: edad, índice de masa corporal, saturación de HBO2, tensión arterial, frecuencia cardiaca, uso de analgesia preventiva, comportamiento de la  analgesia posoperatoria, estado de satisfacción, presencia de complicaciones, técnica quirúrgica, duración del acto quirúrgico y de la anestesia. Resultados: el 50 % tenía  entre 35 y 44 años; 46, 7 % estaban sobrepeso; el 80 % se operó de hipertrofia mamaria; en el 97, 8 % se utilizó la mastopalstia reductora; ninguna presentó cifras altas de tensión arterial antes ni después de la aplicación de la anestesia, el 41,1 % presentó cifras bajas de tensión arterial después de la anestesia; la frecuencia cardiaca estuvo baja en el 31, 1 % después de aplicada la anestesia y alta en el 4, 4 %. La analgesia posoperatoria fue buena en el 87, 8 % de las pacientes; no hubo compromiso ventilatorio en ningún caso y el 100 % mostró satisfacción con la técnica anestésica. Conclusiones: la aplicación de la técnica anestésica permite desarrollar exitosamente las intervenciones quirúrgicas con un mínimo de riesgos y complicaciones para las pacientes.

  19. Rural Electrification of Coban Municipality, Alta Verapaz Department (Guatemala) using Intigis Model; Electrificacion Rural en el Municipio de Coban, Departamento de Alta Verapaz (Guatemala) segun el Modelo Intigis

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez Bravo, J.; Pinedo Pascua, I.; Auger Campos, C.; Cedillo Heine, A.; Gil Garcia, M.

    2009-05-15

    The present project started as an educational exercise for the Renewable Energies and Environment Masters given by the Polytechnic University of Madrid (UPM). It has been developed in collaboration with the research centre CIEMAT, the NGO Energy without Borders (ESF) and the University UPM, with the purpose of analyzing in a real context the application of Geographic Information Systems in renewable energies regional integration. The final aim of our study is to provide the isolated communities, specifically 13 communities in Alta Verapaz (Department of Coban, Guatemala), with the necessary conditions of electrification. This improvement will make possible the sustainable development of the area. Through the analysis of the geographic, technical and economic information gathered, using the IntiGIS methodology we will identify which is the most suitable autonomous generating system to cover the basic needs of the rural population in these Guatemalan communities. (Author) 9 refs.

  20. Black string corrections in variable tension braneworld scenarios

    Science.gov (United States)

    Da Rocha, Roldão; Hoff da Silva, J. M.

    2012-02-01

    Braneworld models with variable tension are investigated, and the corrections on the black string horizon along the extra dimension are provided. Such corrections are encrypted in additional terms involving the covariant derivatives of the variable tension on the brane, providing profound consequences concerning the black string horizon variation along the extra dimension, near the brane. The black string horizon behavior is shown to be drastically modified by the terms corrected by the brane variable tension. In particular, a model motivated by the phenomenological interesting case regarding Eötvös branes is investigated. It forthwith provides further physical features regarding variable tension braneworld scenarios, heretofore concealed in all previous analysis in the literature. All precedent analysis considered uniquely the expansion of the metric up to the second order along the extra dimension, which is able to evince solely the brane variable tension absolute value. Notwithstanding, the expansion terms aftermath, further accomplished in this paper from the third order on, elicits the successive covariant derivatives of the brane variable tension, and their respective coupling with the extrinsic curvature, the Weyl tensor, and the Riemann and Ricci tensors, as well as the scalar curvature. Such additional terms are shown to provide sudden modifications in the black string horizon in a variable tension braneworld scenario.

  1. Automated wireless monitoring system for cable tension using smart sensors

    Science.gov (United States)

    Sim, Sung-Han; Li, Jian; Jo, Hongki; Park, Jongwoong; Cho, Soojin; Spencer, Billie F.; Yun, Chung-Bang

    2013-04-01

    Cables are critical load carrying members of cable-stayed bridges; monitoring tension forces of the cables provides valuable information for SHM of the cable-stayed bridges. Monitoring systems for the cable tension can be efficiently realized using wireless smart sensors in conjunction with vibration-based cable tension estimation approaches. This study develops an automated cable tension monitoring system using MEMSIC's Imote2 smart sensors. An embedded data processing strategy is implemented on the Imote2-based wireless sensor network to calculate cable tensions using a vibration-based method, significantly reducing the wireless data transmission and associated power consumption. The autonomous operation of the monitoring system is achieved by AutoMonitor, a high-level coordinator application provided by the Illinois SHM Project Services Toolsuite. The monitoring system also features power harvesting enabled by solar panels attached to each sensor node and AutoMonitor for charging control. The proposed wireless system has been deployed on the Jindo Bridge, a cable-stayed bridge located in South Korea. Tension forces are autonomously monitored for 12 cables in the east, land side of the bridge, proving the validity and potential of the presented tension monitoring system for real-world applications.

  2. Coarse-Grained Simulations of Membranes under Tension

    CERN Document Server

    Neder, Jörg; Nielaba, Peter; Schmid, Friederike

    2010-01-01

    We investigate the properties of membranes under tension by Monte-Carlo simulations of a generic coarse-grained model for lipid bilayers. We give a comprising overview of the behavior of several membrane characteristics, such as the area per lipid, the monolayer overlap, the nematic order, and pressure profiles. Both the low-temperature regime, where the membranes are in a gel phase, and the high-temperature regime, where they are in the fluid phase, are considered. In the gel state, the membrane is hardly influenced by tension. In the fluid state, high tensions lead to structural changes in the membrane, which result in different compressibility regimes. The ripple state, which is found at tension zero in the transition regime between the fluid and the gel phase, disappears under tension and gives way to an interdigitated phase. We also study the membrane fluctuations in the fluid phase. In the low tension regime the data can be fitted nicely to a suitably extended elastic theory. At higher tensions the elas...

  3. Bending Under Tension Test with Direct Friction Measurement

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Olsson, David Dam; Chodnikiewicz, K.;

    2004-01-01

    enabling accurate measurement of friction and direct determination of lubricant film breakdown for varying normal pressure, sliding speed, tool radius and tool preheat temperature. The transducer is applied in an experimental investigation focusing on limits of lubrication in drawing of stainless steel......A special BUT-transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all measured directly, thus...... showing the influence of varying process conditions and the performance of different lubricants....

  4. Screening bulk curvature in the presence of large brane tension

    CERN Document Server

    Agarwal, Nishant; Khoury, Justin; Trodden, Mark

    2011-01-01

    We study a flat brane solution in an effective 5D action for cascading gravity and propose a mechanism to screen extrinsic curvature in the presence of a large tension on the brane. The screening mechanism leaves the bulk Riemann-flat, thus making it simpler to generalize large extra dimension dark energy models to higher codimensions. By studying an action with cubic interactions for the brane-bending scalar mode, we find that the perturbed action suffers from ghostlike instabilities for positive tension, whereas it can be made ghost-free for sufficiently small negative tension.

  5. Evenness Control of Rapier Loom Tension by Using Neural Network

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The neural network model (NNM) is used to control the evenness of rapier loom tension and to model the uncertain parameters of drafting process. This model can estimate recursively the tension and incorporate predictive control strategies. After controlling the effect testing, it can be seen that the behavior is excellent following different set point and variations, such as the diameter of the beam of weaver, air stream, density of warp and weft, type of textile, etc. An optimum steady state scheme has been fixed in keeping evenness of tension of loom. This method improves obviously the efficiency and quality of production.

  6. Molecular dynamics simulation of liquid-vapor surface tension

    Institute of Scientific and Technical Information of China (English)

    王德; ZENG; Danling; 等

    2002-01-01

    A molecular dynamics simulation model is established based on the well-known Lennard-Jones 12-6 potential function to determine the surface tension of a Lennard-Jones liquid-vapor interface.The simulation is carried out with argon as the working fluid of a given molecular number at different temperature and different truncated radius.It is found that the surface tension of a Lennard-Jones fluid is likely to be bigger for a bigger truncated radius,and tends to be constant after the truncated radius increased to a certain value.It is also found that the surface tension becomes smaller as the temperature increases.

  7. Climate-derived tensions in Arctic security.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Strickland, James Hassler

    2008-09-01

    Globally, there is no lack of security threats. Many of them demand priority engagement and there can never be adequate resources to address all threats. In this context, climate is just another aspect of global security and the Arctic just another region. In light of physical and budgetary constraints, new security needs must be integrated and prioritized with existing ones. This discussion approaches the security impacts of climate from that perspective, starting with the broad security picture and establishing how climate may affect it. This method provides a different view from one that starts with climate and projects it, in isolation, as the source of a hypothetical security burden. That said, the Arctic does appear to present high-priority security challenges. Uncertainty in the timing of an ice-free Arctic affects how quickly it will become a security priority. Uncertainty in the emergent extreme and variable weather conditions will determine the difficulty (cost) of maintaining adequate security (order) in the area. The resolution of sovereignty boundaries affects the ability to enforce security measures, and the U.S. will most probably need a military presence to back-up negotiated sovereignty agreements. Without additional global warming, technology already allows the Arctic to become a strategic link in the global supply chain, possibly with northern Russia as its main hub. Additionally, the multinational corporations reaping the economic bounty may affect security tensions more than nation-states themselves. Countries will depend ever more heavily on the global supply chains. China has particular needs to protect its trade flows. In matters of security, nation-state and multinational-corporate interests will become heavily intertwined.

  8. Skin pass mill tension leveling facility for stainless steel sheets; Stainless kobanyo sukinpasumiru tension leveling setsubi

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-20

    This facility was delivered to Acerinox S.A. (Spain) for surface property improvement, mechanical property improvement and shape correction of bright annealed materials in the end facility of No.3 BAL. Main specifications: (1) Material to be handled: stainless steel sheet (bright annealed cold-rolled steel sheet), (2) Sheet thickness and width: 0.15-2.0mm x 600-1,300mm, (3) Processing speed: 90m/min maximum, (4) Rolling mill: 4 Hi hydraulic depression system, (5) Tension leveler: 6 Hi wet system. Features: (1) Some degree of a flatness only by a skin pass mill through automatic flatness control by work roll bender, 4 Hi skin pass mill with a variable crown backup roll, and shape meter, (2) Stable dead flatness of 0.1% in elongation rate by adding a tension leveler, (3) High-quality bright annealing without any pressed flaw and roll mark by applying an advanced wiper to a skin pass mill, and applying switching control during traveling of welding points to wet leveling and skin pass leveler rolling. (translated by NEDO)

  9. Differences of optic disc appearance between normal tension and high tension glaucoma patients

    Directory of Open Access Journals (Sweden)

    Stojčić Milan

    2011-01-01

    Full Text Available Introduction. The term glaucoma is used to cover a wide range of diseases, whose main feature is optic neuropathy. According to the level of intraocular pressure (IOP, the open angle glaucoma is arbitrarily divided into high tension glaucoma (HTG and normal tension glaucoma (NTG. Objective. The aim of this study was to investigate the differences of optic disc cup appearance between patients with NTG and HTG. Methods. Prospective study included 30 patients (60 eyes with NTG and 30 patients (60 eyes with HTG. IOP was measured by Goldmann applanation tonometry. Examination of optic disc head was performed by indirect ophthalmoscopy with Volk 90 D superfield lens through a dilated pupil to observe qualitative and quantitative parameters. Visual fields were examined in all patients with the Octopus program G1, full threshold strategy (Octopus 500 EZ, Interzeag, Switzerland. Results. Vertical form of optic disc cup was present in 11 eyes with NTG (18.3% and three eyes with HTG (5% (p<0.05. A disc with localized tissue loss (polar notching on the inferior pole was observed in eight eyes with NTG (13.3% and in one eye with HTG (1.7% (p<0.01. Uniformly enlarged, round cup was more frequent in patients with HTG than NTG: 93.3% and 68.3% respectively (p<0.05. Conclusion. The perceived differences indicate a complex multifactorial nature of glaucoma disease and a possible existence of two pathophysiological ways of optic disc changes within the same basic disease.

  10. Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension stresses

    Institute of Scientific and Technical Information of China (English)

    Huailiang WANG; Yupu SONG

    2008-01-01

    In order to meet the requirement for nonlinear analysis and design of mass concrete structures, the deformation behavior and strength of three-graded con-crete specimens 250 mm × 250 mm × 400 mm with a maximum aggregate size of 80 mm and the corresponding wet-screened concrete specimens 150 mm × 150 mm × 300 mm with a maximum aggregate size of 40 mm were studied experimentally. Specimens subjected to biaxial com-pression-tension (C-T) and triaxial compression-compres-sion-tension (C-C-T) stress states. Test data indicate that both the deformation and strength of the mass concrete specimens are lower than those of the corresponding wet-screened concrete small specimens, but the initial tangent modulus of the stress-strain curve of the former is greater than that of the latter. Test results show that the wet-screened effect and size effect of the specimens under com-plex stress states are obvious such that these should be con-sidered in the design of mass concrete structures. In addition, respective failure criteria for mass concrete in prin-cipal stress space and octahedron stress space are proposed.

  11. Tension-tension fatigue behavior of the Space Shuttle strain-isolation-pad material

    Science.gov (United States)

    Phillips, E. P.

    1981-01-01

    The room temperature fatigue behavior of 0.41-cm (0.16-in) thick strain-isolation-pad (SIP) material was explored in a series of constant- and random-amplitude loading tests. The SIP material is used on the Space Shuttle to isolate the ceramic insulating tiles from the strains and deflections of the aluminum alloy airframe. In all tests, 12.7 by 12.7 cm (5.0 by 5.0 in) SIP specimens were subjected to tension-tension loading in the through-the-thickness direction at a frequency of 10 Hz. When subjected to cyclic loading, the SIP material exhibited a monotonic increase in thickness and a monotonic increase in tensile tangent moduli. The rate of thickness growth increased with increasing test stress level and decreased with increasing number cycles endured. Power law equations were found to provide a good representation of the thickness growth rate data. Tensile tangent moduli increased by as much as 80 percent during fatigue tests. Simple cumulative damage fatigue models predicted the mean thickness growth under random-amplitude loading with reasonable accuracy (factor of 2 on life).

  12. Surface tension of molecular liquids: Lattice gas approach

    CERN Document Server

    Maslechko, A; Kulinskii, V

    2016-01-01

    The approach of global isomorphism between the fluid and the Ising model is applied to obtain an expression for the surface tension of the Lennard-Jones fluid on the basis of the information about the Ising model. This is done in a broad interval of temperatures along the phase coexistence, and is valid both in 2D and 3D. The relation between the critical amplitudes of the surface tension of the fluid and the Ising model is derived in the vicinity of the critical point. The obtained theoretical estimates agree well with the literature results for the surface tension. The methodology is demonstrated for the 2D LJ fluid on the basis of the exact solution of the 2D Ising model and is tested for the 3D LJ fluid. As a result, an expression for the surface tension without any fitting parameter is derived.

  13. Tension density as counter force to the Lorentz force density

    Science.gov (United States)

    Nozaki, Hiroo; Senami, Masato; Ichikawa, Kazuhide; Tachibana, Akitomo

    2016-08-01

    It is confirmed numerically that the tension density defined in quantum field theory is the counter force to the Lorentz force density. We take benzenedithiol in a nonequilibrium steady state as an example for the numerical demonstration of the balance between these densities. While we use simply a nonequilibrium Green’s function method for a quantum conduction state instead of computations based on quantum field theory, the balance between the tension density and the Lorentz force density can be confirmed. The tension density is free from the relaxation time ansatz and defined as a local quantity. The tension density may give a novel viewpoint to the understanding of the physics of electrical conduction.

  14. Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

    Science.gov (United States)

    Gugliotti, Marcos; Baptisto, Mauricio S.; Politi, Mario J.

    2004-01-01

    Surface tensions gradients were generated in a thin liquid film because of the local increase in temperature, for demonstration purposes. This is performed using a simple experiment and allows different alternatives for heat generation to be used.

  15. Surface tension driven shaping of adhesive microfluidic channel walls

    DEFF Research Database (Denmark)

    Janting, Jakob; Storm, Elisabeth K.; Geschke, Oliver

    2005-01-01

    The feasibility of making microfluidic channels with different wall geometries using adjacent lines of dispensed adhesive between substrates has been studied. Important parameters for the geometry have been identified to be: surface tension (adhesive / substrates), adhesive viscosity / thixotropy...

  16. Linear dispersive decay estimates for vortex sheets with surface tension

    OpenAIRE

    Spirn, Daniel; Wright, J. Douglas

    2009-01-01

    We consider the amplitude decay for the linearized equations governing irrotational vortex sheets and water waves with surface tension. Using oscillatory integral estimates, we prove that the magnitude of the amplitude decays faster than $t^−1/3$

  17. Softening of edges of solids by surface tension

    International Nuclear Information System (INIS)

    Surface tension tends to minimize the area of interfaces between pieces of matter in different thermodynamic phases, be they in the solid or the liquid state. This can be relevant for the macroscopic shape of very soft solids and lead to a roughening of initially sharp edges. We calculate this effect for a Neo-Hookean elastic solid, with assumptions corresponding to actual experiments, namely the case where an initially sharp edge is rounded by the effect of surface tension felt when the fluid surrounding the soft solid (and so surface tension) is changed at the solid/liquid boundary. We consider two opposite limits where the analysis can be carried to the end, the one of a shallow angle and the one of a very sharp angle. Both cases yield a discontinuity of curvature in the state with surface tension although the initial state had a discontinuous slope. (paper)

  18. Stability in the Stefan problem with surface tension (I)

    OpenAIRE

    Hadzic, Mahir; Guo, Yan

    2008-01-01

    We develop a high-order energy method to prove asymptotic stability of flat steady surfaces for the Stefan problem with surface tension - also known as the Stefan problem with Gibbs-Thomson correction.

  19. Influence of Surface Tension on Nuclear Collective Properties

    CERN Document Server

    Goncharova, N G

    2016-01-01

    Rigidities of even-even nuclei were estimated and compared with nuclear charge radii. Correlation of maximal nuclear rigidities with minimal values of r0 parameters was revealed. Influence of effective surface tension on nuclear properties was discussed.

  20. Practitioners conducting educational design research: Tales of tension and triumph

    NARCIS (Netherlands)

    McKenney, Susan

    2014-01-01

    McKenney, S. (2013). Practitioners conducting educational design research: Tales of tension and triumph. Keynote address at the annual meeting of the European Association for Practitioner Research on Improving Learning. November 27-29, Biel/Bienne, Switzerland.

  1. Coulomb vs. physical string tension on the lattice

    CERN Document Server

    Burgio, G; Reinhardt, H; Vogt, H

    2015-01-01

    We investigate the precise relationship between the Coulomb and the physical (Wilson) string tension on the lattice, as the former is generally known to give an upper bound for the latter. We give evidence that the two string tensions are in a one to one correspondence at zero temperature, while they become unrelated at finite temperatures. More precisely, we show that the standard lattice calculations of the Coulomb gauge confinement scenario are always tied to the spatial string tension, which is known to survive the deconfinement phase transition and to cause screening effects in the quark-gluon plasma. Our analysis is based on the identification and elimination of center vortices which allows to control the physical string tension and study its effect on the Coulomb gauge observables. We also show how alternative definitions of the Coulomb potential may sense the deconfinement transition, although a true static Coulomb gauge order parameter for the phase transition is still elusive on the lattice.

  2. Stress distribution and fracture behavior of beryllium compact tension specimens

    International Nuclear Information System (INIS)

    Compact tension specimens of beryllium (Be) were designed to study fracture behavior and mechanical properties. The local stress distribution near a notch in a compact tension specimen was measured in situ by the combination of an X-ray stress analysis and a custom-designed load device. The fracture morphology was observed by scanning electron microscopy. The result showed that the local stresses near the notch tip are much higher than in other areas, and cracking occurs first in that area. The load-crack opening displacement curve of the Be compact tension specimen was obtained, and used to calculate the fracture toughness as 15.7 MPa√m. The compact tension specimen fracture surfaces were mainly characterized by cleavage fracture over three different areas. Cleavage micro-cracks along the basal slip plane were formed at the crack tip, and their growth was controlled by the primary stress after reaching a critical length

  3. Exploring cultural tensions in cross-cultural social work practice.

    Science.gov (United States)

    Yan, Miu Chung

    2008-10-01

    Discussion of cultural tension in the social work literature is piecemeal. As part of a grounded theory study, this article reports some major findings on cultural tensions experienced by 30 frontline social workers. Cultural tensions caused by cultural similarities and differences among social workers, clients, organizations, and society are multifaceted. Social workers, however, are always at the center of the tensions. Findings indicate that the social work profession may need to consider the neutrality claim of the profession, the different experience of ethnic minority social workers, and the need of critical reflexivity for reflective practitioners. Implications for social work practice, social work education for ethnic minority social workers, and social work research are discussed.

  4. Laparoscopic tension-free hernioplasty for lumbar hernia.

    Science.gov (United States)

    Maeda, K; Kanehira, E; Shinno, H; Yamamura, K

    2003-09-01

    Lumbar hernia, a defect of the posterior abdominal wall, is a very rare condition. The repair of a posterior abdominal wall hernia by simply closing the hernia port with sutures may not be adequate, especially when the herniation is due to a weakness in the abdominal wall. Recently, a simple, logical method of tension-free repair has become a popular means for the treatment of various abdominal wall hernias. Previous studies have advocated the use of tension-free repair for lumbar hernia; the technique uses a mesh replacement and requires an extensive incision. Herein we present a case of superior lumbar hernia. Our technique consisted of a laparoscopic tension-free hernioplasty with the application of a Prolene mesh. This technique, which provides an excellent operative view, is safe, feasible, and minimally invasive. We conclude that laparoscopic tension-free repair should be the preferred option for the treatment of lumbar hernia.

  5. Tensioned Rollable Ultra-light Solar array System (TRUSS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRUSS is a structurally efficient solar array concept that utilizes a TRAC rollable boom and tension-stiffened structure to exceed the program requirements for very...

  6. Second Inflection Point of the Surface Tension of Water

    Science.gov (United States)

    Kalova, Jana; Mares, Radim

    2012-06-01

    The theme of a second inflection point of the temperature dependence of the surface tension of water remains a subject of controversy. Using data above 273 K, it is difficult to get a proof of existence of the second inflection point, because of experimental uncertainties. Data for the surface tension of supercooled water and results of a molecular dynamics study were included into the exploration of existence of an inflection point. A new term was included into the IAPWS equation to describe the surface tension in the supercooled water region. The new equation describes the surface tension values of ordinary water between 228 K and 647 K and leads to the inflection point value at a temperature of about 1.5 °C.

  7. The effects of ambient impurities on the surface tension

    Directory of Open Access Journals (Sweden)

    Ponce-Torres A.

    2016-01-01

    Full Text Available A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a small glass cover. Ambient contamination produced a sharp decrease of the surface tension of ultra-pure water. The presence of an anionic surfactant in the free surface of an aqueous solution did not inhibit the action of impurities coming from the ambient. Impurities can influence the dynamical behavior of the free surface in flows dominated by the surface tension. Therefore, a careful control of that influence can be crucial in many applications of fluid mechanics.

  8. The effects of ambient impurities on the surface tension

    Science.gov (United States)

    Ponce-Torres, A.; Vega, E. J.

    2016-03-01

    A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a small glass cover. Ambient contamination produced a sharp decrease of the surface tension of ultra-pure water. The presence of an anionic surfactant in the free surface of an aqueous solution did not inhibit the action of impurities coming from the ambient. Impurities can influence the dynamical behavior of the free surface in flows dominated by the surface tension. Therefore, a careful control of that influence can be crucial in many applications of fluid mechanics.

  9. Seepage mitigation at TransAlta's Rundle intake No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Sobkowicz, J.; Cullum-Kenyon, S. [Thurber Engineering Ltd., Calgary, AB (Canada); Szojka, A. [TransAlta Utilities Corp., Calgary, AB (Canada)

    2006-07-01

    As part of its spray system of power generation, TransAlta operates the Rundle power canal, forebay and powerhouse located near Canmore, Alberta. Two penstocks run from the Rundle forebay to the powerhouse. Ongoing seepage problems around the intake to Unit No. 2 have been a problem for TransAlta, causing recurrent sinkholes, unpredictable variations in piezometric levels within the dam, and seepage flows at its toe. In order to assess the cause of the seepage and make a decision to proceed with mitigation, TransAlta conducted more frequent monitoring of these parameters, several surveys along the dam, and monitoring of pore water temperatures. The mitigation involved construction of a grout curtain under and adjacent to the intake and was performed from the ground surface as well as from within the penstock. This work required shutting down the penstock to Unit No. 2, lowering the water level in the forebay, and de-rating flow to Unit No. 1. This paper presented a brief history of the facility contributing to the cause of the seepage and the monitoring undertaken to assess its extent and seriousness. It also discussed the design and progress of the grouting program, including the response of the geotechnical instrumentation to the drilling and grouting process. Last, in order to evaluate the effectiveness of the remedial work, the post-grouting monitoring was examined. Comments were made on the usefulness of the various monitoring instruments and techniques used to determine dam performance prior to, during and after the grouting work. 1 ref., 9 figs.

  10. Plan de alta para personas con enfermedad pulmonar obstructiva crónica

    Directory of Open Access Journals (Sweden)

    Luz Marina Céspedes Salgado

    2006-01-01

    Full Text Available El plan de alta busca asegurar unos cuidados acordes con las necesidades y los requerimientos de la persona una vez egresa de la institución de salud, y debe constituirse en una guía básica en especial para la atención de aquéllos con patologías crónicas, como es la enfermedad pulmonar obstructiva crónica, que por su complejidad demanda múltiples cuidados para asegurar una intervención integral con miras al logro de una mejor adaptación, a identificar posibles complicaciones y a mejorar su calidad de vida. La experiencia de haber asumido el rol de hija y enfermera de un padre con enfermedad pulmonar obstructiva crónica (EPOC, y la alta incidencia de esta enfermedad, motivaron la elaboración de este plan de alta; fueron muchos los cuidados y muchas las necesidades y los cuestionamientos que se daban día a día, desde asegurar una adecuada comunicación hasta un conocimiento de los signos y síntomas de urgencia que indicaban una exacerbación, del uso adecuado de los medicamentos, de la importancia de la oxigenoterapia a largo plazo, de proporcionarle una dieta acorde con las recomendaciones y un ambiente favorable para sus condiciones de salud para, en últimas, alcanzar un entorno armónico, físico, familiar y espiritual.

  11. Cultivos de alta densidad celular por retención interna: aplicación a la fermentación continua de etanol High cell density cultures produced by internal retention: application in continuous ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Godoy Rubén Darío

    2004-12-01

    Full Text Available El etanol ha generado gran interés por su potencial como combustible alternativo. No obstante, para que este producto sea competitivo económicamente, es necesario desarrollar procesos de fermentación que incrementen la baja productividad volumétrica lograda en cultivos convencionales (por lote o continuo, por medio de técnicas que permitan altas concentraciones celulares y reduzcan la inhibición por producto. Uno de los métodos empleados frecuentemente involucra la recirculación celular; por ello, en este trabajo se desarrolló un reactor de membrana incorporando un módulo de filtración, con unidades tubulares de 5 u,m en acero inoxidable, dentro de un fermentador de tanque agitado de 3L, para investigar su aplicación en la producción continua de etanol. Los efectos de la concentración celular y la caída de presión transmembranal sobre el flux de permeado fueron evaluados para probar el desempeño del módulo de filtración. Previa selección de las condiciones de fermentación (30 °C, 1,25 -1,75 vvm, pH 4,5, el sistema con retención celular interna fue operado en el cultivo continuo de Saccharomyces cerevisiae a partir de sacarosa. La permeabilidad de las unidades filtrantes fue mantenida mediante la aplicación de pulsos de aire. Más del 97% de las células cultivadas fueron retenidas en el fermentador, alcanzándose una concentración celular de 51 g/L y una productividad promedio de etanol, en el cultivo con retención celular, de 8,51 g/L.h, la cual fue dos veces mayor a la que se obtiene en un cultivo continuo convencional. Palabras clave: reactor de membrana, Saccharomyces cerevisiae, fermentación alcohólica, recirculación celular.Ethanol has provoked great interest due to its potential as an alternative fuel. Nevertheless, fermentation processes must be developed by increasing the low volumetric productivity achieved in conventional cultures (batch or continuous to make this product become economically competitive

  12. Advanced multi-stud tensioners for Convoy plants

    International Nuclear Information System (INIS)

    The multiple stud tensioners for the reactor vessels of the new Emsland and Neckarwestheim 2 convoy plants in FR Germany are built to handle 52 reactor pressure vessel studs with an M210X8 thread. They are equipped with two stud turning robots and a total of four stud elongation measuring devices so as to reduce the time taken for multi-stud tensioner operations on the vessel. (author)

  13. Pulmonary Surfactant Surface Tension Influences Alveolar Capillary Shape and Oxygenation

    OpenAIRE

    Ikegami, Machiko; Weaver, Timothy E.; Grant, Shawn N.; Whitsett, Jeffrey A.

    2009-01-01

    Alveolar capillaries are located in close proximity to the alveolar epithelium and beneath the surfactant film. We hypothesized that the shape of alveolar capillaries and accompanying oxygenation are influenced by surfactant surface tension in the alveolus. To prove our hypothesis, surfactant surface tension was regulated by conditional expression of surfactant protein (SP)-B in Sftpb−/− mice, thereby inhibiting surface tension–lowering properties of surfactant in vivo within 24 hours after d...

  14. Method for Measuring Changes in Surface Tension on Agar

    OpenAIRE

    Weisberg, David S.; Dworkin, Martin

    1983-01-01

    The surface tension of agar surfaces was determined by measuring the contact angles formed by drops of various hydrophobic liquids on the surface and then calculating the composite surface free energy function by solving a series of simultaneous equations derived from these data. This method was used to measure the change in the surface tension of agar produced by the addition of various concentrations of albumin. The resulting curve was typical of the effect of increasing concentrations of s...

  15. Influence of plasma on surface tension of hydrocarbons

    International Nuclear Information System (INIS)

    The results of studying of plasma influence on the surface tension of liquid hydrocarbons and distilled water during experiments with corona discharge are presented. The charged particles influence on the surface tension of fluids with different electrical conductivity is demonstrated. Current-voltage characteristics of corona discharge are measured. It is shown that the flow of charged particles leads to fragmentation of liquids with low conductivity into small droplets. The effect of corona discharge on the stearin combustion rate is investigated

  16. Why is surface tension a force parallel to the interface?

    OpenAIRE

    Marchand, Antonin; Weijs, Joost H.; Snoeijer, Jacco H.; Andreotti, Bruno

    2011-01-01

    A paperclip can float on water. Drops of mercury refuse to spread on a surface. These capillary phenomena are macroscopic manifestations of molecular interactions, and can be explained in terms of surface tension. For students, the concept of surface tension is quite challenging since the microscopic intuition is often in conflict with the common macroscopic interpretations. In this paper we address a number of conceptual questions that are often encountered when teaching capillarity. By answ...

  17. Influence of external factors on surface tension of water

    International Nuclear Information System (INIS)

    The influence of various external factors such as magnetization, electric discharge, electromagnetic irradiation in cantimetric range, air and osone saturation, riching by the metal ions on the surface tension coefficient of water has been experimentally investigated. It has been established that these actions lead to decreasing surface tension coefficient of drinking water. The value of this decreasing considerably has depended on nature and degree of action

  18. Finite time singularities for water waves with surface tension

    OpenAIRE

    Castro, Angel; Córdoba, Diego; Fefferman, Charles; Gancedo, Francisco; Gómez-Serrano, Javier

    2012-01-01

    Here we consider the 2D free boundary incompressible Euler equation with surface tension. We prove that the surface tension does not prevent a finite time splash or splat singularity, i.e. that the curve touches itself either in a point or along an arc. To do so, the main ingredients of the proof are a transformation to desingularize the curve and a priori energy estimates.

  19. Water surface tension modulates the swarming mechanics of Bacillus subtilis

    OpenAIRE

    Ke, Wan-Ju; Hsueh, Yi-Huang; Cheng, Yu-Chieh; Wu, Chih-Ching; Liu, Shih-Tung

    2015-01-01

    Many Bacillus subtilis strains swarm, often forming colonies with tendrils on agar medium. It is known that B. subtilis swarming requires flagella and a biosurfactant, surfactin. In this study, we find that water surface tension plays a role in swarming dynamics. B. subtilis colonies were found to contain water, and when a low amount of surfactin is produced, the water surface tension of the colony restricts expansion, causing bacterial density to rise. The increased density induces a quorum ...

  20. Surface tension of liquid alumina from contactless techniques

    International Nuclear Information System (INIS)

    Full Text: We report new data on surface tension of liquid alumina from 2300 to 3200 K. Aerodynamic levitation of CO2 laser heated liquid drops allowed contactless measurement of vibration frequencies directly related to surface tension. Consistent data were obtained on drops of various weights ranging from 20 to 160 mg. It was also shown that oxydo-reducing character of the atmosphere does not modify sensible the results. (author)

  1. Zero surface tension limit of viscous surface waves

    OpenAIRE

    Tan, Zhong; Wang, Yanjin

    2012-01-01

    We consider the free boundary problem for a layer of viscous, incompressible fluid in a uniform gravitational field, lying above a rigid bottom and below the atmosphere. For the "semi-small" initial data, we prove the zero surface tension limit of the problem within a local time interval. The unique local strong solution with surface tension is constructed as the limit of a sequence of approximate solutions to a special parabolic regularization. For the small initial data, we prove the global...

  2. Flow-induced dynamic surface tension effects at nanoscale

    OpenAIRE

    Lukyanov, A. V.

    2010-01-01

    The aim of this study is to investigate flow-induced dynamic surface tension effects, similar to the well-known Marangoni phenomena, but solely generated by the nanoscale topography of the substrates. The flow-induced surface tension effects are examined on the basis of a sharp interface theory. It is demonstrated how nanoscale objects placed at the boundary of the flow domain result in the generation of substantial surface forces acting on the bulk flow.

  3. Simulation of two-phase flow with varying surface tension.

    OpenAIRE

    Lervåg, Karl Yngve

    2008-01-01

    This thesis is a study on the effects of varying surface tension along an interface separating two fluids. Varying surface tension leads to tangential forces along the interface. This is often called the Marangoni effect. These forces are discussed in detail, and two test cases are considered to analyse the Marangoni effect, and to verify the present implementation. The first test studies steady-state two-phase flow where the fluids are separated with plane interfaces and the flow is driv...

  4. On the Low Surface Tension of Lung Surfactant

    OpenAIRE

    Zhang, Hong; Wang, Yi E.; Fan, Qihui; Zuo, Yi Y.

    2011-01-01

    Natural lung surfactant contains less than 40% disaturated phospholipids, mainly dipalmitoylphosphatidylcholine (DPPC). The mechanism by which lung surfactant achieves very low near-zero surface tensions, well below its equilibrium value, is not fully understood. To date, the low surface tension of lung surfactant is usually explained by a squeeze-out model which predicts that upon film compression non-DPPC components are gradually excluded from the air–water interface into a surface-associat...

  5. Tension pneumothorax, is it a really life-threatening condition?

    OpenAIRE

    Yoon, Jeong Seob; Choi, Si Young; Suh, Jong Hui; Jeong, Jin Yong; Lee, Bae Young; Park, Yong Gue; Kim, Chi Kyung; Park, Chan Beom

    2013-01-01

    Background Tension pneumothorax is a life-threatening occurrence that is infrequently the consequence of spontaneous pneumothorax. The aim of this study was to identify the risk factors for the development of tension pneumothorax and its effect on clinical outcomes. Methods We reviewed patients who were admitted with spontaneous pneumothorax between August 1, 2003 and December 31, 2011. Electronic medical records and the radiological findings were reviewed with chest x-ray and high-resolution...

  6. Rising Russian-Western Tensions in the Global Security Context

    Institute of Scientific and Technical Information of China (English)

    Ji Zhiye

    2008-01-01

    Tensions between Russia and the West have grown increasingly apparent in recent years. This can be demonstrated in Moscow's ideological confrontations with the West, the intensifying rivalry over military strategic force, the fierce geopolitical confrontation, and grave contentions over energy resources between the two. The author concludes that in short, rising Russia-US tensions can hardly be remedied. It is a matter of political significance that merits careful consideration by the international community.

  7. Modeling and characterization of strengthened concrete tension members

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Stang, Henrik

    2011-01-01

    The structural potential for cracking of externally strengthened concrete tension members, can be predicted with three parameters, describing the structural cracking potential based on fracture mechanical properties of the of concrete and interface between concrete and strengthening medium....... With these parameters, it is possible to design reinforcement and obtain a required cracking behavior of a given structure. Design recommendations for single and multiple cracking of the tension specimen are given in terms of fracture mechanical parameters, and a structural stiffness parameter....

  8. Surface tension and related thermodynamic quantities of aqueous electrolyte solutions

    CERN Document Server

    Matubayasi, Norihiro

    2013-01-01

    Surface tension provides a thermodynamic avenue for analyzing systems in equilibrium and formulating phenomenological explanations for the behavior of constituent molecules in the surface region. While there are extensive experimental observations and established ideas regarding desorption of ions from the surfaces of aqueous salt solutions, a more successful discussion of the theory has recently emerged, which allows the quantitative calculation of the distribution of ions in the surface region. Surface Tension and Related Thermodynamic Quantities of Aqueous Electrolyte Solutions provides a d

  9. Human Uterine Wall Tension Trajectories and the Onset of Parturition

    OpenAIRE

    Peter Sokolowski; Francis Saison; Warwick Giles; Shaun McGrath; David Smith; Julia Smith; Roger Smith

    2010-01-01

    Uterine wall tension is thought to be an important determinant of the onset of labor in pregnant women. We characterize human uterine wall tension using ultrasound from the second trimester of pregnancy until parturition and compare preterm, term and twin pregnancies. A total of 320 pregnant women were followed from first antenatal visit to delivery during the period 2000-2004 at the John Hunter Hospital, NSW, Australia. The uterine wall thickness, length, anterior-posterior diameter and tran...

  10. Human uterine wall tension trajectories and the onset of parturition.

    Directory of Open Access Journals (Sweden)

    Peter Sokolowski

    Full Text Available Uterine wall tension is thought to be an important determinant of the onset of labor in pregnant women. We characterize human uterine wall tension using ultrasound from the second trimester of pregnancy until parturition and compare preterm, term and twin pregnancies. A total of 320 pregnant women were followed from first antenatal visit to delivery during the period 2000-2004 at the John Hunter Hospital, NSW, Australia. The uterine wall thickness, length, anterior-posterior diameter and transverse diameter were determined by serial ultrasounds. Subjects were divided into three groups: women with singleton pregnancies and spontaneous labor onset, either preterm or term and women with twin pregnancies. Intrauterine pressure results from the literature were combined with our data to form trajectories for uterine wall thickness, volume and tension for each woman using the prolate ellipsoid method and the groups were compared at 20, 25 and 30 weeks gestation. Uterine wall tension followed an exponential curve, with results increasing throughout pregnancy with the site of maximum tension on the anterior wall. For those delivering preterm, uterine wall thickness was increased P < 0.05 compared with term. For twin pregnancies intrauterine volume was increased compared to singletons (P < 0.001, but wall thickness was not. There was no evidence for increased tension in those delivering preterm or those with twin gestations. These data are not consistent with a role for high uterine wall tension as a causal factor in preterm spontaneous labor in singleton or twin gestations. It seems likely that hormonal differences in multiple gestations are responsible for increased rates of preterm birth in this group rather than increased tension.

  11. The effects of ambient impurities on the surface tension

    OpenAIRE

    Ponce-Torres A.; Vega E. J.

    2016-01-01

    A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a...

  12. Determinación de aminas aromaticas por cromatografia liquida de alta resolución.

    OpenAIRE

    Gutiérrez Bouzán, Mª Carmen; Crespi Rosell, Martin

    1989-01-01

    Este trabajo consiste en la puesta a punto del metodo analítico para la determinación por cromatografia liquida de alta resolución (HPLC) de las aminas aromáticas empleadas más frecuentemente en la fabricación de colorantes sulfurosos: m-tolilendiamina, p-fenilendiamina, o-toluidina, p-toluidina, anilina, p-aminofenol, difenilamina, y p-hidroxidifenilamina. La longitud de onda de detección es de 260 nm. El principal objetivo del presente estudio es la consecución de un método de análisis p...

  13. El entrenamiento interválico de alta intensidad para el rendimiento deportivo

    OpenAIRE

    Alvarez Fernández, Iker

    2014-01-01

    El entrenamiento interválico de alta intensidad (HIIT) ha sido una parte más de los programas de entrenamiento para mejorar el rendimiento deportivo, pero su efecto puntual en los entrenamientos de deportistas altamente entrenados no se conoce en su totalidad, a pesar de ser un elemento importante de la preparación deportiva. En esta revisión veremos cómo diversas investigaciones demuestran los diferentes efectos y adaptaciones que provoca el HIIT en estos deportistas con el fin de la mejora ...

  14. Efeito de alta pressão no processo de demolha de bacalhau

    OpenAIRE

    Salvador, Ângelo Miguel Correia

    2009-01-01

    Este trabalho experimental teve como objectivo recorrer à tecnologia de alta pressão hidrostática com o intuito de acelerar o processo de demolha de bacalhau, em termos de saída de sal e entrada de água. Inicialmente tentou-se desenvolver uma metodologia rápida para quantificação do NaCl mediante condutivimetria. Contudo, como se verificaram diferenças entre os resultados obtidos por este método e o método químico usado neste trabalho, a quantificação do sal por condutivimet...

  15. Neurodesarrollo en egresados de la terapia intensiva neonatal a los 6 meses del alta hospitalaria

    OpenAIRE

    Dayami Armas-Guerra; Tania Mejías-Martín; Ana Nastia Tamayo-Ortiz; María Caridad Jardines-Carballosa

    2012-01-01

    Se abordó estudio descriptivo longitudinal de 16 recién nacidos egresados del servicio de Neonatología del Hospital Pediátrico de Holguín, desde febrero a junio del 2009. Se les evaluó desde el punto de vista neurológico a los seis meses del alta hospitalaria. Un 25% presentaron anormalidad del examen neurológico. Las alteraciones leves y moderadas se comportaron igual. El sexo femenino fue el más afectado, la menor edad gestacional y el peso menor de 1500 gramos predispusieron a la aparición...

  16. Factores de riesgo, asociados a intento de suicidio, comparando factores de alta y baja letalidad

    OpenAIRE

    Garcia Rabago, Horacio; Sahagun Flores, Jose Ernesto; Ruiz Gomez, Alfonso; Sanchez Ureña, Gustavo Manuel; Tirado Vargas, Juan Carlos; Gonzalez Gamez, Jaime Guillermo

    2012-01-01

    Objetivo El propósito del estudio fue Identificar los factores de riesgo más frecuentes asociados a intento de suicidio para determinar si existen diferencias entre los factores de riesgo presentes en pacientes con tentativa de baja letalidad y los de alta letalidad. Método Se entrevistaron 106 pacientes de ambos sexos, con diagnóstico de intento de suicidio, hospitalizados en una unidad psiquiátrica, divididos en dos grupos: uno pacientes con tentativa suicida de baja letalidad y otro con te...

  17. Cultivo de cachama blanca en altas densidades y en dos sistemas cerrados

    OpenAIRE

    Germán Poleo; José Vicente Aranbarrio; Lismen Mendoza; Oneida Romero

    2011-01-01

    El objetivo de este trabajo fue evaluar la tolerancia de la cachama blanca, Piaractus brachypomus, a cultivos en altas densidades en sistemas cerrados. Novecientos alevines de 44,3±26 g de peso, se distribuyeron en seis tanques de concreto, con 4,8 m³ de agua. Tres tanques presentaron cero recambio de agua (SCR), y en otros tres, el agua se hizo circular a través de un bioclarificador (SRA). Ambos tratamientos presentaron fuerte aireación para mantener los sólidos en suspensión y suministrar ...

  18. Contribución al modelado unidimensional en motores de dos tiempos de altas prestaciones

    OpenAIRE

    JIMENEZ MACEDO, VICTOR DANIEL

    2013-01-01

    Un modelo de simulación presenta muchas ventajas en el campo del desarrollo de motores de combustión interna alternativos. Su utilidad es doble. Por un lado, para entender la naturaleza de los fenómenos físicos que suceden en el interior del motor, y por otro, con el fin de optimizar el diseño de los sistemas que integran el mismo. El principal objetivo de esta tesis es desarrollar un modelo de un motor de dos tiempos de 125 cc de altas prestaciones para caracterizar la fluidodinámica interna...

  19. Diseño de sistemas WIFI en trenes de alta velocidad

    OpenAIRE

    Alonso Barbero, Carlos

    2015-01-01

    En este Trabajo Fin de Grado se realiza el diseño de un sistema que proporcione acceso a internet a los usuarios en un tren de alta velocidad. Se busca conseguir un sistema inalámbrico (WIFI) que permita un gran número de conexiones simultáneas con un ancho de banda suficiente para todas ellas. En este proyecto se buscará una tecnología capaz de cumplir estos requisitos, realizando un estudio de las tecnologías disponibles actualmente (WiMAX, satélite, 3G/4G). Las diferentes tecnologías pr...

  20. La identificación de alumnos con altas habilidades: enfoques y dimensiones actuales

    OpenAIRE

    Rojo Martínez, Angela

    1996-01-01

    La tesis ha quedado estructurada en dos partes. En la primera, se desarrolla y fundamenta el marco teórico de este trabajo de investigación, desde el que se presentan los principales planteamientos conceptuales que han ayudado y están contribuyendo a definir la alta habilidad intelectual, haciendo especial hincapié en enfoques amplios y variados, que permitan que la identificación de esos sujetos se realice considerando junto a su potencial intelectual otras muchas y diferentes variables. Y l...

  1. CARCINOMA BRONQUÍOLO-ALVEOLAR: ASPECTOS NA TOMOGRAFIA COMPUTADORIZADA DE ALTA RESOLUÇÃO

    OpenAIRE

    Moreira Luiza Beatriz Melo; Marchiori Edson; Melo Alessandro Severo Alves de; Magnago Marcelo; Muniz Maria Angélica Soares; Irion Klaus

    2002-01-01

    O carcinoma bronquíolo-alveolar é um tipo de carcinoma broncogênico de crescimento insidioso, que surge nas paredes das vias aéreas distais e se dissemina utilizando o septo alveolar como um estroma, preservando a arquitetura pulmonar. Neste trabalho foram analisadas as tomografias computadorizadas de alta resolução de 17 pacientes com carcinoma bronquíolo-alveolar. Ao contrário do relatado na literatura, foram observados predomínio no sexo masculino (71%) e maior freqüência da associação das...

  2. Simulación de altas prestaciones para modelos orientados al individuo

    OpenAIRE

    Mostaccio, Diego Javier

    2007-01-01

    Existen diversos campos de la biología que necesitan realizar experimentos para estudiar el modelo de comportamiento de diferentes especies. En la presente tesis, se analizan las diferentes posibilidades de análisis en base a sistemas de simulación de altas prestaciones donde se ha desarrollado un laboratorio virtual que permite a los científicos experimentar con sus modelos y realizar pruebas mediante métodos de simulación distribuida. El modelo utilizado es un Modelo Orientado al Individuo ...

  3. ESTUDIO DE ALUMNOS DE EDUCACIÓN SECUNDARIA OBLIGATORIA CON ALTAS CAPACIDADES INTELECTUALES

    OpenAIRE

    Anda-Moreno, Verónica

    2012-01-01

    El presente Trabajo de Fin de Máster realizado para la obtención del título del Máster en Formación de Profesorado de Educación Secundaria Obligatoria, Bachillerato, Formación Profesional y Enseñanza de Idiomas, Especialidad en Física y Química, de la Universidad Internacional de La Rioja trata del estudio de Alumnos con Altas Capacidades Intelectuales de la Educación Secundaria Obligatoria del sistema educativo español. En el entorno escolar, siempre se han presentado casos de niños...

  4. Herramientas TIC para la intervención educativa en estudiantes con altas capacidades

    OpenAIRE

    Tárraga Mínguez, Raúl; Sanz-Cervera, Pilar; Pastor Cerezuela, Gemma; Fernández Andrés, María Inmaculada

    2014-01-01

    Los estudiantes con altas capacidades procesan la información de manera distinta, ya que estos poseen una elevada creatividad e implicación en la tarea. Este hecho implica la necesidad de llevar acabo una intervención educativa específica. Algunos modelos teóricos han demostrado la efectividad del uso de las TICs en la intervención de este tipo de alumnado, por lo que en el presente artículo se incluyen diferentes herramientas TIC que pueden ser de gran utilidad para los docentes. Entre estas...

  5. Altas capacidades. Propuesta de intervención para el aprendizaje de la historia

    OpenAIRE

    Gárriz Forné, Javier

    2013-01-01

    El presente estudio de carácter teórico, es una aproximación al conocimiento de las necesidades educativas del alumnado con altas capacidades intelectuales y pretende desarrollar una propuesta educativa que responda a esas necesidades, desde las ciencias sociales, concretamente desde la historia. Partiendo de la legislación vigente y teniendo en cuenta el planteamiento de algunos autores que abordan esta problemática, primero, comenzaré perfilando las características de este alumnado; pos...

  6. Alumnado con altas capacidades intelectuales: Programa de intervención

    OpenAIRE

    Arranz Melado, Luis Alfonso

    2015-01-01

    En el presente trabajo se hace un breve resumen conceptual de la literatura científica sobre las altas capacidades intelectuales. Se hace referencia a conceptos, teorías y modelos. Luego se analiza algunas de las características del alumnado con necesidades educativas especiales. Seguidamente, se hace referencia a los procedimientos y técnicas de evaluación de los estudiantes con necesidades educativas especiales. Se hace mención de las diferentes modalidades de respuesta educativa aplica...

  7. Procesos de automatización cognitiva en alumnado con altas capacidades intelectuales

    OpenAIRE

    Juan Montero-Linares; José I. Navarro-Guzmán; Manuel Aguilar-Villagrán

    2013-01-01

    Proponemos desde el enfoque del procesamiento de la información, el estudio de características cognitivas que faciliten la identificación de las altas capacidades. A tal fin, elaboramos una tarea de habilidad de segmentación silábica que, a partir del modelo propuesto por Baddeley sobre la memoria de trabajo y la distinción entre procesos automáticos y controlados, nos permitiese comprobar las diferencias en cuanto a la capacidad de automatización de la información y si los indicadores propue...

  8. Alumnos con altas capacidades intelectuales: Propuesta de Intervención

    OpenAIRE

    Cano-Aguirre, María Isabel

    2012-01-01

    En este trabajo se ha realizado una revisión bibliográfica acerca de las características de los alumnos de altas capacidades intelectuales, su funcionamiento cerebral y los proyectos que se aplican en la actualidad. En la segunda parte se ha realizado una investigación con un enfoque cualitativo en la cual se proporcionó un cuestionario a un grupo de profesionales que participan en proyectos dirigidos a este tipo de alumnado con el fin de detectar la situación actual en la que se encuentran. ...

  9. Género, adolescencia y altas capacidades : un acercamiento a la afectividad

    OpenAIRE

    González González, Leybiz

    2012-01-01

    El presente estudio fue realizado en un grupo de chicas y chicos adolescentes pertenecientes a la Asociación Onubense de Altas Capacidades ARETÉ. Sus propósitos consistieron en analizar el aspecto afectivo-relacional a través de una perspectiva de género, en la que fueron identificadas las vivencias y áreas de conflictos psicológicos, las preocupaciones, temores, satisfacciones e insatisfacciones presentes. Asimismo, se pretendió develar algunos elementos de la conformación de ...

  10. La evaluación psicopedagógica del alumnado con altas capacidades intelectuales

    OpenAIRE

    Moliner García, Odet; Comes Nolla, Gabriel; Luque, Antonio; Díaz Pareja, Elena María

    2008-01-01

    Tras un análisis de la normativa estatal y autonómica sobre la evaluación psicopedagógica del alumnado con altas capacidades intelectuales, se presentan los aspectos más relevantes que toda evaluación psicopedagógica debe contemplar para que resulte lo más eficaz posible, y permita ofrecer una respuesta educativa adecuada a dicho alumnado e identifique los recursos y apoyos que pueda precisar. Tales decisiones se concretan en el informe psicopedagógico y este artículo recoge...

  11. Alumnos con indicios de altas capacidades en Educación Infantil

    OpenAIRE

    López-Gómez, Sheila

    2012-01-01

    En las aulas se encuentran niños de altas capacidades que no han sido diagnosticados y por lo tanto no se está atendiendo a sus necesidades como se debiera. Mediante este trabajo de fin de grado se ha pretendido señalar las características principales que permiten al tutor del aula reconocer a estos alumnos y poderles derivar a los orientadores que señalarán las pautas necesarias para conseguir que el alumno se desarrolle en plenitud y se sienta integrado en el aula. Para ello se van a exp...

  12. Resultados del relevamiento de HI en el Cielo Austral: 3. Relevamiento de Nubes de Alta Velocidad

    Science.gov (United States)

    Morras, R.; Bajaja, E.; Arnal, E. M.; Pöppel, W. G. L.

    Los resultados del relevamiento de HI del Hemisferio Austral fueron reprocesados con el fin de incrementar su sensibilidad. Así, se utilizó esta nueva base de datos con el fin de obtener un nuevo relevamiento de Nubes de Alta Velocidad en el cielo austral. El ruido r.m.s. alcanzado es de 0.015-0.020 K, con una resolución espectral de 8 km/seg. El cubrimiento espacial del relevamiento mejora en un factor 16 al realizado por Bajaja et al (1985).

  13. Alta hospitalar do recém-nascido prematuro: experiência do pai

    OpenAIRE

    Bruna de Souza Lima Marski; Natália Custodio; Flávia Corrêa Porto de Abreu; Débora Falleiros de Melo; Monika Wernet

    2016-01-01

    RESUMO Objetivo: descrever a experiência do pai frente à alta do filho prematuro da Unidade de Terapia Intensiva Neonatal e apontar intervenções para a promoção dessa experiência. Método: pesquisa qualitativa com oito pais que adotou o Interacionismo Simbólico como referencial teórico e a pesquisa de narrativa temática como referencial metodológico. Resultados: a análise dos dados permitiu descrever a experiência do pai a partir de três unidades temáticas: 'limites para a paternidade', 'al...

  14. USO DE IMÁGENES SATELITALES DE ALTA RESOLUCIÓN PARA GENERAR CARTOGRAFÍA

    OpenAIRE

    Patricio Zavala; Carlos Zavala

    2002-01-01

    Se presenta la metodología aplicada en la ciudad de Arica, Norte de Chile, para generar cartografía de altura de construcciones, mediante el análisis digital de una imagen satelital de alta resolución. Para ello, nos basamos en el cálculo de la longitud de las sombras que se derivan de distintas edificaciones, y del azimut solar de una imagen IRS 1C, que fue remuestreada mediante convolución cúbica a 5 metros. Este trabajo está basado fundamentalmente en los logros alcanzados en el desarrollo...

  15. SAÓ, sistema de ayuda ortoépica para la lectura en voz alta del valenciano

    OpenAIRE

    Forcada, Mikel L.; Beltran i Calvo, Vicent; Segura i Llopes, Carles; Colomina i Castanyer, Jordi

    2003-01-01

    Este proyecto se propone elaborar un programa informático que ayudará a los locutores de radio y televisión y, en general, a cualquier persona, a leer el valenciano correctamente en voz alta. El sistema resultante, denominado SAÓ (sistema de ayuda ortoépica), anotará automáticamente el texto con marcas sencillas que indicarán la pronunciación correcta en algunos casos difíciles, usando un ordenador de sobremesa común. En particular, podrá ser usado para enseñar l...

  16. Impacto de la regulación ambiental en las actividades de la alta gerencia corporativa

    OpenAIRE

    Rina Tigrera Carneiro

    2003-01-01

    El presente ensayo tiene por finalidad exponer algunas consideraciones y reflexiones acerca del impacto que ha generado la regulación ambiental en las actividades de la alta gerencia corporativa. Para tal fin, fue necesario realizar una revisión documental de las distintas bibliografías, documentos y escritos especializados en el área, tanto en el ámbito nacional como latinoamericano; la cual, permitió llegar a las siguientes conclusiones: la introducción de las distintas regulaciones de índo...

  17. Computación de altas prestaciones ecológica

    OpenAIRE

    González, Lucía; Uribe, Federico; Balladini, Javier; Sánchez, Laura

    2011-01-01

    La computación de altas prestaciones ha tenido, por décadas, el único objetivo de incrementar la velocidad de procesamiento de las aplicaciones computacionalmente complejas. Dado el tamaño actual de las supercomputadoras, el consumo energético de las mismas es tan elevado que producen un tremendo impacto económico. Además, la falta de explotaci ón de las energías renovables y limpias hacen que la producción energética afecte signi- cativamente en lo ecológico y social. Estos factores nos ...

  18. Caracterizando a los consumidores en los mercados de consumo de alta frecuencia

    OpenAIRE

    Juan Carlos Gáquez Abab; Manuel Sánchez Pérez

    2007-01-01

    Los mercados de consumo de alta frecuencia presentan rasgos particulares en cuanto a la diversidad de estrategias de precio, constantes promociones en precio, publicidad masiva o estrategias de marca que hacen que la identificación de segmentos sea especialmente interesante para la empresa. En el presente trabajo se lleva a cabo un análisis de segmentación sobre datos de panel que pretende identificar cuántos segmentos existen y describir cuál es su comportamiento en relación a...

  19. Patients with tension-type headaches feel stigmatized

    Directory of Open Access Journals (Sweden)

    Sanjay Prakash

    2016-01-01

    Full Text Available The author, a sufferer of tension-type headache (TTH, believes that the word "tension" in "tension-type headache" carries a social stigma and that patients do not accept a diagnosis of TTH readily. TTH is the most common primary headache disorder. The disability of TTH as a burden of society is greater than that of migraine. Absenteeism because of TTH is higher than that due to migraine. However, patients with TTH do not go for consultation. Even the prevalence of new daily persistent headache (NDPH is 12 times higher at the headache clinic than that of chronic TTH (CTTH. These points hint that TTH patients probably do not want to visit the clinic. The author believes that it could be because of the stigma attached to "tension." Herein, the author has noted the first responses given by 50 consecutive patients with TTH when they were told that they had been suffering from TTH. The first answer of 64% of patients with TTH was "I do not have any tension/stress ." This denial is similar to the denial declared by patients with depression. Depression and tension are similar in the sense that both are considered as a signs of personal weakness. Such a preconception in the society creates a stigma, and patients deny the diagnosis, conceal symptoms, and become reluctant to seek help and treatment.

  20. Patients with tension-type headaches feel stigmatized.

    Science.gov (United States)

    Prakash, Sanjay

    2016-01-01

    The author, a sufferer of tension-type headache (TTH), believes that the word "tension" in "tension-type headache" carries a social stigma and that patients do not accept a diagnosis of TTH readily. TTH is the most common primary headache disorder. The disability of TTH as a burden of society is greater than that of migraine. Absenteeism because of TTH is higher than that due to migraine. However, patients with TTH do not go for consultation. Even the prevalence of new daily persistent headache (NDPH) is 12 times higher at the headache clinic than that of chronic TTH (CTTH). These points hint that TTH patients probably do not want to visit the clinic. The author believes that it could be because of the stigma attached to "tension." Herein, the author has noted the first responses given by 50 consecutive patients with TTH when they were told that they had been suffering from TTH. The first answer of 64% of patients with TTH was "I do not have any tension/stress." This denial is similar to the denial declared by patients with depression. Depression and tension are similar in the sense that both are considered as a signs of personal weakness. Such a preconception in the society creates a stigma, and patients deny the diagnosis, conceal symptoms, and become reluctant to seek help and treatment.

  1. Estimating intercellular surface tension by laser-induced cell fusion

    International Nuclear Information System (INIS)

    Intercellular surface tension is a key variable in understanding cellular mechanics. However, conventional methods are not well suited for measuring the absolute magnitude of intercellular surface tension because these methods require determination of the effective viscosity of the whole cell, a quantity that is difficult to measure. In this study, we present a novel method for estimating the intercellular surface tension at single-cell resolution. This method exploits the cytoplasmic flow that accompanies laser-induced cell fusion when the pressure difference between cells is large. Because the cytoplasmic viscosity can be measured using well-established technology, this method can be used to estimate the absolute magnitudes of tension. We applied this method to two-cell-stage embryos of the nematode Caenorhabditis elegans and estimated the intercellular surface tension to be in the 30–90 µN m−1 range. Our estimate was in close agreement with cell–medium surface tensions measured at single-cell resolution. (communication)

  2. Tension-Enhanced Hydrogen Evolution Reaction on Vanadium Disulfide Monolayer.

    Science.gov (United States)

    Pan, Hui

    2016-12-01

    Water electrolysis is an efficient way for hydrogen production. Finding efficient, cheap, and eco-friendly electrocatalysts is essential to the development of this technology. In the work, we present a first-principles study on the effects of tension on the hydrogen evolution reaction of a novel electrocatalyst, vanadium disulfide (VS2) monolayer. Two electrocatalytic processes, individual and collective processes, are investigated. We show that the catalytic ability of VS2 monolayer at higher hydrogen coverage can be efficiently improved by escalating tension. We find that the individual process is easier to occur in a wide range of hydrogen coverage and the collective process is possible at a certain hydrogen coverage under the same tension. The best hydrogen evolution reaction with near-zero Gibbs free energy can be achieved by tuning tension. We further show that the change of catalytic activity with tension and hydrogen coverage is induced by the change of free carrier density around the Fermi level, that is, higher carrier density, better catalytic performance. It is expected that tension can be a simple way to improve the catalytic activity, leading to the design of novel electrocatalysts for efficient hydrogen production from water electrolysis. PMID:26924817

  3. Autocuidado do cuidador familiar de adultos ou idosos dependentes após a alta hospitalar

    Directory of Open Access Journals (Sweden)

    Sibely Rabaça Dias da Costa

    2014-12-01

    Full Text Available Este artigo apresenta uma compreensão sobre o autocuidado do cuidador familiar segundo a teoria de Dorothea Orem. Resulta de uma pesquisa qualitativa com aporte da Teoria Fundamentada nos Dados, utilizando-se das técnicas de visita domiciliar, registro de notas de campo e entrevista semiestruturada com 11 cuidadores, após a internação de familiar em um Hospital Universitário de Minas Gerais. Foram obtidas quatro categorias, destacando uma categoria central, em torno da qual se analisaram as facilidades, dificuldades e estratégias para o autocuidado do cuidador. Entre as dificuldades, foram evidenciadas: tempo insuficiente para os cuidados com a saúde e, entre as facilidades, o apoio de outros familiares. As principais estratégias foram: apoio na fé; revezamento nos cuidados e recursos na comunidade. Concluiu-se que orientações no momento da alta e o acompanhamento de enfermagem após a alta contribuem para o autocuidado do cuidador, atuando sobre suas dificuldades e estimulando suas potencialidades.

  4. Circolazione troposferica e stratosferica media mensile e stagionale per l'analisi co .... ente della circolazione dell' alta stratosfera

    Directory of Open Access Journals (Sweden)

    M. MONTALTO

    1962-06-01

    Full Text Available La scarsità di dati a livelli superiori a 100 mb rende finora praticamenteimpossibile l'analisi sinottica della circolazione nell'alta stratosfera,a meno di sostituire i dati mancanti con altri estrapolati. Lo studio preliminaredelle circolazioni mensili e stagionali nella troposfera, nella bassa emedia stratosfera e nell'alta stratosfera ha rivelato che esse sono in certomodo interdipendenti. Ciò è posto qualitativamente in evidenza, ad esempio,dalla corrispondenza dei cunei e delle saceature delle configurazionibariclie dell'alta stratosfera con le aree oceaniche e continentali dell'EmisferoNord. Considerandole correnti a getto come sintesi delle grandi perturbazionidell'alta troposfera atte ad influire sulla struttura e circolazionedell'alta stratosfera, le conclusioni precedenti mi hanno indotto a programmareuna classificazione della struttura e della circolazione osservate, suciascuna delle stazioni aerologiche Mediterranee, in relazione alla loro posizionerispetto alle correnti a getto, onde reperire sperimentalmente le formuleche consentano una logica estrapolazione delle osservazioni correnti ai livellidesiderati.

  5. The critical tension in the Cascading DGP model

    International Nuclear Information System (INIS)

    We study the behaviour of weak gravitational fields in the 6D Cascading DGP model using a bulk-based approach. To deal with the ambiguity in the thin limit of branes of codimension higher than one, we consider a specific regularization of the internal structure of the branes where the 5D brane can be considered thin with respect to the 4D one. We consider the solutions corresponding to pure tension sources on the 4D brane, and study perturbations at first order around these background solutions. We adopt a 4D scalar-vector-tensor decomposition, and focus on the scalar sector of perturbations. We show that, in a suitable 4D limit, the trace part of the 4D metric perturbations obeys a decoupled equation which suggests that it is a ghost for background tensions smaller than a critical tension, while it is a healthy field otherwise. We give a geometrical interpretation of the existence of the critical tension and of the reason why the relevant field is a ghost or not depending on the background tension. We however find a value of the critical tension which is different from the one already found in the literature. Differently from the results in the literature, our analysis implies that, choosing the background tension suitably, we can construct ghost-free models for any value of the free parameters of the theory. We suggest that the difference lies in the procedure used to evaluate the pillbox integration across the codimension-2 brane. We confirm the validity of our analysis by performing numerically the integration in a particular case where the solution inside the thick cod-2 brane is known exactly. We stress that the singular structure of the perturbation fields in the nested branes set-ups is very subtle, and that great care has to be taken when deriving the codimension-2 junction conditions

  6. Well-posedness of the water-wave problem with surface tension

    OpenAIRE

    Ming, Mei; Zhang, Zhifei

    2008-01-01

    In this paper, we prove the local well-posedness of the water wave problem with surface tension in the case of finite depth by working in the Eulerian setting. For the flat bottom, as surface tension tends to zero, the solution of the water wave problem with surface tension converges to the solution of the water wave problem without surface tension.

  7. Tensions in Beginning Teachers' Professional Identity Development, Accompanying Feelings and Coping Strategies

    Science.gov (United States)

    Pillen, Marieke; Beijaard, Douwe; Brok, Perry den

    2013-01-01

    This study examined tensions encountered by 182 beginning teachers during their professional identity development, the feelings that accompanied these tensions and the ways they tried to cope with these. Professional identity tensions stem from an unbalanced personal and professional side of (becoming) a teacher. Tensions that are often mentioned…

  8. Uso de hormigones con fibras de ultra-alta resistencia para el desarrollo de conexiones entre elementos prefabricados

    Directory of Open Access Journals (Sweden)

    Morán, F.

    2010-12-01

    Full Text Available The performance suitability of precast concrete structures is determined by the design and construction of connections between elements. In spite of its simplicity, the use of bond connections through bar reinforcement splices is limited by issues related to long splice lengths required and reinforcement congestion. Reinforcement splices embedded in Ultra High Performance Fibre Reinforced Concrete (UHPFRC were tested in beam specimens, as part of an on-going investigation to develop a novel typology of beam-column connection between precast elements using UHPFRC. Elements made up of two precast elements joined through reinforcement splices in a central region poured with UHPFRC, and without using closed stirrups or vertical ties were tested in beam tests. The experimental results for splice lengths between 10 db and 20 db exhibited an adequate performance to connections undergoing load and unload cycles, being this an unfavourable condition for bond capacity, and using short covers and transversal spacing between splices, under 0.7 db. It is therefore clear that the higher tensile capacity and ductility of UHPFRC have a positive effect on confinement, bond conditions and force transference as well as a stiffness effect.

    El adecuado comportamiento de estructuras prefabricadas de hormigón se encuentra condicionado por el diseño y ejecución de las conexiones entre sus elementos. El uso de conexiones rígidas basadas en la adherencia mediante el solape de armaduras se ve en muchos casos limitado, a pesar de su simplicidad, por problemas derivados de las considerables longitudes de solape requeridas y la congestión en el refuerzo. En el desarrollo de este estudio, enmarcado dentro del trabajo de investigación para la puesta a punto de una conexión para pórticos prefabricados con el uso de hormigones de altas especificaciones reforzados con fibras (Ultra High Performance Fibre Reinforced Concrete-[UHPFRC], se evaluó experimentalmente

  9. Effects of eugenol on resting tension of rat atria.

    Science.gov (United States)

    Olivoto, R R; Damiani, C E N; Kassouf Silva, I; Lofrano-Alves, M S; Oliveira, M A; Fogaça, R T H

    2014-04-01

    In cardiac and skeletal muscle, eugenol (μM range) blocks excitation-contraction coupling. In skeletal muscle, however, larger doses of eugenol (mM range) induce calcium release from the sarcoplasmic reticulum. The effects of eugenol are therefore dependent on its concentration. In this study, we evaluated the effects of eugenol on the contractility of isolated, quiescent atrial trabeculae from male Wistar rats (250-300 g; n=131) and measured atrial ATP content. Eugenol (1, 3, 5, 7, and 10 mM) increased resting tension in a dose-dependent manner. Ryanodine [100 µM; a specific ryanodine receptor (RyR) blocker] and procaine (30 mM; a nonspecific RyR blocker) did not block the increased resting tension induced by eugenol regardless of whether extracellular calcium was present. The myosin-specific inhibitor 2,3-butanedione monoxime (BDM), however, reversed the increase in resting tension induced by eugenol. In Triton-skinned atrial trabeculae, in which all membranes were solubilized, eugenol did not change resting tension, maximum force produced, or the force vs pCa relationship (pCa=-log [Ca2+]). Given that eugenol reduced ATP concentration, the increase in resting tension observed in this study may have resulted from cooperative activation of cardiac thin filaments by strongly attached cross-bridges (rigor state).

  10. Rupture of a biomembrane under dynamic surface tension

    Science.gov (United States)

    Bicout, D. J.; Kats, E.

    2012-03-01

    How long will a fluid membrane vesicle stressed with a steady ramp of micropipette last before rupture? Or conversely, how high should the surface tension be to rupture such a membrane? To answer these challenging questions we developed a theoretical framework that allows for the description and reproduction of dynamic tension spectroscopy (DTS) observations. The kinetics of the membrane rupture under ramps of surface tension is described as a succession of an initial pore formation followed by the Brownian process of the pore radius crossing the time-dependent energy barrier. We present the formalism and a derive (formal) analytical expression of the survival probability describing the fate of the membrane under DTS conditions. Using numerical simulations for the membrane prepared in an initial state with a given distribution of times for pore nucleation, we study the membrane lifetime (or inverse of rupture rate) and distribution of membrane surface tension at rupture as a function of membrane characteristics like pore nucleation rate, the energy barrier to failure, and tension loading rate. It is found that simulations reproduce the main features of DTS experiments, particularly the pore nucleation and pore-size diffusion-controlled limits of membrane rupture dynamics. This approach can be adapted and applied to processes of permeation and pore opening in membranes (electroporation, membrane disruption by antimicrobial peptides, vesicle fusion).

  11. Dynamic surface tension of natural surfactant extract under superimposed oscillations.

    Science.gov (United States)

    Reddy, Prasika I; Al-Jumaily, Ahmed M; Bold, Geoff T

    2011-01-01

    Surfactant dysfunction plays a major role in respiratory distress syndrome (RDS). This research seeks to determine whether the use of natural surfactant, Curosurf™ (Cheisi Farmaceutici, Parma, Italy), accompanied with pressure oscillations at the level of the alveoli can reduce the surface tension in the lung, thereby making it easier for infants with RDS to maintain the required level of functional residual capacity (FRC) without collapse. To simulate the alveolar environment, dynamic surface tension measurements were performed on a modified pulsating bubble surfactometer (PBS) type device and showed that introducing superimposed oscillations about the tidal volume excursion between 10 and 70 Hz in a surfactant bubble lowers interfacial surface tension below values observed using tidal volume excursion alone. The specific mechanisms responsible for this improvement are yet to be established; however it is believed that one mechanism may be the rapid transient changes in the interfacial area increase the number of interfacial binding sites for surfactant molecules, increasing adsorption and diffusion to the interface, thereby decreasing interfacial surface tension. Existing mathematical models in the literature reproduce trends noticed in experiments in the range of breathing frequencies only. Thus, a modification is introduced to an existing model to both incorporate superimposed pressure oscillations and demonstrate that these may improve the dynamic surface tension in the alveoli. PMID:20883997

  12. Measurement of dynamic surface tension by mechanically vibrated sessile droplets.

    Science.gov (United States)

    Iwata, Shuichi; Yamauchi, Satoko; Yoshitake, Yumiko; Nagumo, Ryo; Mori, Hideki; Kajiya, Tadashi

    2016-04-01

    We developed a novel method for measuring the dynamic surface tension of liquids using mechanically vibrated sessile droplets. Under continuous mechanical vibration, the shape of the deformed droplet was fitted by numerical analysis, taking into account the force balance at the drop surface and the momentum equation. The surface tension was determined by optimizing four parameters: the surface tension, the droplet's height, the radius of the droplet-substrate contact area, and the horizontal symmetrical position of the droplet. The accuracy and repeatability of the proposed method were confirmed using drops of distilled water as well as viscous aqueous glycerol solutions. The vibration frequency had no influence on surface tension in the case of pure liquids. However, for water-soluble surfactant solutions, the dynamic surface tension gradually increased with vibration frequency, which was particularly notable for low surfactant concentrations slightly below the critical micelle concentration. This frequency dependence resulted from the competition of two mechanisms at the drop surface: local surface deformation and surfactant transport towards the newly generated surface. PMID:27131706

  13. Exploratory experimental investigations on post-tensioned structural glass beams

    Directory of Open Access Journals (Sweden)

    Christian Louter

    2014-06-01

    Full Text Available Corresponding author: Dr. ir. Christian Louter, Steel Structures Laboratory (ICOM, School of Architecture, Civil and Environmental Engineering (ENAC, École Polytechnique Fédérale de Lausanne (EPFL, GC B3 505, Station 18, Lausanne CH-1015, Switzerland. Tel.: +41 21 6932427; Fax: +41 21 6932868; E-mail: christian.louter@epfl.ch The mechanical response of post-tensioned glass beams is explored in this paper. This is done through bending experiments on post-tensioned glass beam specimens with either mechanically anchored or adhesively bonded steel tendons by which a beneficial pre-stress is inflicted on the glass beams. In addition, reference beams with identical geometry but without tendons are tested. From the results of the bending experiments it can be seen that the post-tensioned glass beams reach higher initial fracture loads than the reference glass beams. Furthermore, the post-tensioned glass beams develop a significant post-fracture reserve. From this it is concluded that post-tensioning a glass beam is a feasible concept, which provides increased initial fracture strength and enhanced post-fracture performance.

  14. The critical tension in the Cascading DGP model

    CERN Document Server

    Sbisà, Fulvio

    2014-01-01

    We study the behaviour of weak gravitational fields in the 6D Cascading DGP model using a bulk-based approach. To deal with the ambiguity in the thin limit of branes of codimension higher than one, we consider a specific regularization of the internal structure of the branes where the 5D brane can be considered thin with respect to the 4D one. We consider the solutions corresponding to pure tension sources on the 4D brane, and study perturbations at first order around these background solutions. We adopt a 4D scalar-vector-tensor decomposition, and focus on the scalar sector of perturbations. We show that, in a suitable 4D limit, the trace part of the 4D metric perturbations obeys a decoupled equation which suggests that it is a ghost for background tensions smaller than a critical tension, while it is a healthy field otherwise. We give a geometrical interpretation of the existence of the critical tension and of the reason why the relevant field is a ghost or not depending on the background tension. We howeve...

  15. Posttraumatic delayed tension pneumocephalus: Rare case with review of literature

    Science.gov (United States)

    Kankane, Vivek Kumar; Jaiswal, Gaurav; Gupta, Tarun Kumar

    2016-01-01

    Pneumocephalus is commonly seen after head and facial trauma, ear infections, and tumors of the skull base or neurosurgical interventions. In tension pneumocephalus, the continuous accumulation of intracranial air is thought to be caused by a “ball valve” mechanism. In turn, this may lead to a mass effect on the brain, with subsequent neurological deterioration and signs of herniation. Tension pneumocephalus is considered a life-threatening, neurosurgical emergency burr-hole evacuation was performed and he experienced a full recovery. However, more invasive surgery was needed to resolve the condition. Delayed tension pneumocephalus is extremely rare and considered a neurosurgical emergency. Pneumocephalus is a complication of head injury in 3.9–9.7% of the cases. The accumulation of intracranial air can be acute (trauma and underwent urgent surgical intervention. Burr-hole placement in the right frontal region, evacuation of tension pneumocephalus. Tension pneumocephalus is a life-threatening neurosurgical emergency case, which needs to undergo immediate surgical intervention.

  16. Surface tension of highly magnetized degenerate quark matter

    CERN Document Server

    Lugones, G

    2016-01-01

    We study the surface tension of highly magnetized three flavor quark matter within the formalism of multiple reflection expansion (MRE). Quark matter is described as a mixture of free Fermi gases composed by quarks $u$, $d$, $s$ and electrons, in chemical equilibrium under weak interactions. Due to the presence of strong magnetic fields the particles' transverse motion is quantized into Landau levels, and the surface tension has a different value in the parallel and transverse directions with respect to the magnetic field. We calculate the transverse and longitudinal surface tension for different values of the magnetic field and for quark matter drops with different sizes, from a few fm to the bulk limit. For baryon number densities between $2-10$ times the nuclear saturation density, the surface tension falls in the range $2 - 20$ MeV /fm$^{2}$. The largest contribution comes from strange quarks which have a surface tension an order of magnitude larger than the one for $u$ or $d$ quarks and more than two ord...

  17. Regulating mechanical tension at compartment boundaries in Drosophila.

    Science.gov (United States)

    Michel, Marcus; Dahmann, Christian

    2016-10-01

    During animal development, cells with similar function and fate often stay together and sort out from cells with different fates. In Drosophila wing imaginal discs, cells of anterior and posterior fates are separated by a straight compartment boundary. Separation of anterior and posterior cells requires the homeodomain-containing protein Engrailed, which is expressed in posterior cells. Engrailed induces the expression of the short-range signaling molecule Hedgehog in posterior cells and confines Hedgehog signal transduction to anterior cells. Transduction of the Hedgehog signal in anterior cells is required for the separation of anterior and posterior cells. Previous work showed that this separation of cells involves a local increase in mechanical tension at cell junctions along the compartment boundary. However, how mechanical tension was locally increased along the compartment boundary remained unknown. A recent paper now shows that the difference in Hedgehog signal transduction between anterior and posterior cells is necessary and sufficient to increase mechanical tension. The local increase in mechanical tension biases junctional rearrangements during cell intercalations to maintain the straight shape of the compartment boundary. These data highlight how developmental signals can generate patterns of mechanical tension important for tissue organization.

  18. Luxómetro medidor de enfoque para señal alta de lámpara de ferrocarril

    OpenAIRE

    Rodríguez García, Carlos

    2007-01-01

    Ante la complejidad para la correcta instalación y verificación de las Señales Altas de Lámpara para Ferrocarril. Nace un proyecto cuyo objetivo es medir la Iluminancia de los focos de las Señales Altas y calcular el enfoque correcto de la señal. Para ello se estudio el mejor sistema para determinar la verificación de un foco de Señal Alta. Se ha logrado diseñar y construir un Luxómetro capaz de medir el enfoque de la señal. Para llevar a cabo este fin, se ha diseña...

  19. Mejoramiento genético para tolerancia a altas temperaturas y resistencia a mosaico dorado en frijol común

    Directory of Open Access Journals (Sweden)

    Juan Carlos Rosas

    2000-01-01

    Full Text Available Mejoramiento genético para tolerancia a altas temperaturas y resistencia a mosaico dorado en frijol común. Entre 1994-95 se identificaron fuentes de frijol tolerantes a altas temperaturas mediante la evaluación de germoplasma y líneas mejoradas en Choluteca y Nacaome (≤ 50 msnm, en la región Sur de Honduras. La tolerancia al calor de los mejores genotipos fue confirmada en Geneva, Nueva York, EE.UU., bajo condiciones de invernadero con temperatura controlada (35/27 oC día/noche. Posteriormente, se realizaron cruzamientos para desarrollar líneas de grano rojo-pequeño tolerantes al calor y resistentes al VMDF y a otros factores limitantes. Las poblaciones segregantes F2-F5 fueron evaluadas por caracteres múltiples incluyendo VMDF, bacteriosis, baja fertilidad, roya, valor agronómico y valor comercial del grano. En 1998, 217 líneas F6 y F7 fueron evaluadas en el distrito de riego Lempa-Acahuapa (20 msnm, región Pacífica de El Salvador, por tolerancia a altas temperaturas y al VMDF. Estas mismas líneas se evaluaron en la localidad de Liberia, en la región Noroeste de Costa Rica, por tolerancia a altas temperaturas; y en El Zamorano, Honduras por resistencia a bacteriosis, mancha angular y roya. Se logró identificar un grupo de líneas que superaron a los testigos comerciales bajo condiciones de altas temperaturas en El Salvador y Costa Rica. Algunas de las líneas seleccionadas presentaron alta resistencia al VMDF en El Salvador, resistencia moderada a mustia en Costa Rica, y excelente comportamiento agronómico y valor comercial del grano

  20. The effects of land use change on mercury distribution in soils of Alta Floresta, Southern Amazon

    International Nuclear Information System (INIS)

    This study presents the spatial distribution, degree of contamination and storage capacity of Hg in surface forest and pasture soils from Alta Floresta, Southern Amazon, a significant gold mining site from 1980 to 1996. During that period, average annual gold production was about 6.5 tons, with an estimated Hg annual emission to the environment of about 8.8 tons, 60-80% of it being emitted to the atmosphere. Mercury sources to the region are mining sites and gold-dealer shops at the city of Alta Floresta, where gold is smelted and commercialized. Mercury concentrations in forest soils (15-248 ng g-1, average=61.9 ng g-1) were 1.5-3.0 times higher than in pasture soils (10-74 ng g-1, average=33.8 ng g-1), suggesting strong re-mobilization after deforestation. Highest Hg concentrations were found within a distance of 20-30 km from mining sites in both soil types. The influence of the refining operations within the city of Alta Floresta, however, was less clear. Somewhat higher concentrations were observed only within a 5 km radius from the city center where gold-dealer shops are located. Wind direction controls the spatial distribution of Hg. Background concentrations (15-50 ng g-1) were generally found at the outer perimeter of the sampling grid, about 40 km from sources. This suggests that Hg released from mining and refining activities undergoes rapid deposition. Estimated cumulative Hg burdens for the first 10 cm of soil averaged 8.3 mg m-2 and 4.9 mg m-2, for forest and pasture soils respectively and compare well with ultisols and hydromorphic oxisols, but were lower than those found in yellow-red and yellow latosols and podsols from other Amazonian areas. Our results show that changing land use in the Amazon is a strong re-mobilizing agent of Hg deposited on soils from the atmosphere. - Land use change is a strong re-mobilizing agent of Hg distribution in Amazon soils

  1. Tensiones residuales en uniones soldadas por FSW en aluminio 7075-T651 Residual stresses in 7075-T651 FSW joint

    Directory of Open Access Journals (Sweden)

    Leonardo N. Tufaro

    2012-12-01

    Full Text Available Las tensiones residuales pueden ser un aspecto de relevancia en la integridad estructural de componentes en servicio, pudiendo presentar una importante influencia sobre la vida a la fatiga, entre otros mecanismos de falla. El proceso de soldadura por fricción-agitación (FSW ha revolucionado en los últimos años el campo de la tecnología de la soldadura. Su mayor aplicación se ha dado en las aleaciones de aluminio, aunque hoy en día se utiliza para prácticamente todos los materiales. Una de las ventajas enunciadas de este proceso es el menor nivel de tensiones residuales resultantes, debido a que se produce en estado sólido por lo que los gradientes térmicos durante la soldadura son menores. Entre las aleaciones de aluminio de uso estructural, las aleaciones termoenvejecibles de la serie 7XXX se utilizan habitualmente en la industria aeronáutica y aeroespacial debido a su alta resistencia mecánica. El objetivo del presente trabajo es analizar el efecto de la velocidad de avance en FSW sobre las tensiones residuales en juntas de aluminio AA7075-T651, mediante la técnica de seccionamiento. Se soldaron probetas de dicha aleación de 150x150x4mm mediante FSW, variando la velocidad de avance entre 51 y 206 mm.min-1. Durante la soldadura se adquirieron los ciclos térmicos. Posteriormente se midieron las tensiones residuales longitudinales a distintas distancias del cordón de soldadura, en cada caso. A partir de los ciclos térmicos adquiridos se obtuvieron los gradientes térmicos en la zona de medición. Las tensiones residuales máximas se encontraron entre 52 y 78 MPa, correspondiente entre 10 y 15 % del límite de fluencia del material. Las mismas aumentaron con la velocidad de avance, consistentemente con un aumento en el gradiente térmico observado. Dichos valores de tensiones residuales son menores que los obtenidos para la soldadura de estos materiales mediante procesos del tipo GMAW.Residual stresses could be a relevant issue in

  2. Emigración, transformaciones sociales y cambios culinarios en la Mixteca Alta (Oaxaca, Mexico Emigracão, mudancas sociais e culinarias na Mixteca Alta (Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Esther Katz

    2009-12-01

    Full Text Available Como en otras regiones de México, los campesinos de la Mixteca Alta (Estado de Oaxaca, han dejado de depender de la agricultura ya que reciben remesas de sus parientes emigrados en los Estados Unidos. El fenómeno de la migración, presente en esta región desde hace varias décadas, ha aumentado exponencialmente en los últimos diez años. La mayoría de los adultos jóvenes dejan sus hogares, los cuales están ahora compuestos de madres e hijos o abuelos y nietos. Con el dinero de las remesas el equipo de las cocinas se ha modernizado y se han incorporado cambios técnicos en las preparaciones culinarias; se come más carne y alimentos procesados y menos verduras silvestres. Al mismo tiempo, varios programas de desarrollo impulsados por el gobierno están provocando cambios profundos sobre la economía familiar, la organización social y el papel de las mujeres. Ahora, el statuseconómico de las familias ya no depende de la extensión de sus tierras, sino del número de sus miembros trabajando en “el Norte”. No obstante, el rico patrimonio culinario de esta población sigue vivo, particularmente para las comidas festivas.Como em outras regiões do México, os indígenas da Mixteca Alta (Estado de Oaxaca quase já não vivem da agricultura, mas das remessas dos seus parentes emigrados que moram nos Estados Unidos. O fenômeno da migração, presente nessa regi­ão há varias décadas, aumentou muito nos últimos dez anos, uma vez que a maioria dos adultos jovens emigra, ficando em geral mãe e filhos ou os avôs e os netos na região natal. Com o dinheiro das remessas, essas famílias conseguem trocar os equipamentos de cozinha, modernizando-a, o que implica em mudanças técnicas nas preparações culinárias. Por outro lado, com essa melhora também se come mais carne e alimentos industrializados e menos produtos da terra. Ao mesmo tempo, vários programas de desenvolvimento incentivados pelo governo estão provocando mudan

  3. Diseño y estudio de viabilidad de una planta depuradora mediante lagunas de alta carga

    OpenAIRE

    Fructuoso Martín, Marc

    2015-01-01

    Diseño y es tudio de viabilidad de planta depuradora Marc Fructuoso Martín mediante lagunas de alta carga Curso 2014 - 2015 1 Resumen La s lagunas de alta carga (HRAP) son una versión mejorada del sistema de depuración de aguas con lagunaje tradicional. A caballo entre las propiedades de las lagunas tradicionales y las estaciones depuradoras de agua residual (EDARs) convencionales, las HRAP ofrecen una depuración igual de eficiente que tratamien...

  4. Malária pulmonar: aspectos na tomografia computadorizada de alta resolução - relato de caso

    Directory of Open Access Journals (Sweden)

    Rodrigues Rosana

    2004-01-01

    Full Text Available Neste trabalho é relatado o caso de paciente do sexo masculino, de 38 anos de idade, que desenvolveu quadro de malária com comprometimento pulmonar. A tomografia computadorizada de alta resolução evidenciou espessamento de septos interlobulares e de bainhas peribroncovasculares, com áreas esparsas de atenuação em vidro fosco e de consolidações, além de derrame pleural bilateral, aspectos compatíveis com edema pulmonar. O paciente recebeu tratamento específico, evoluindo bem e tendo alta 11 dias após a internação.

  5. Malária pulmonar: aspectos na tomografia computadorizada de alta resolução - relato de caso

    OpenAIRE

    Rodrigues Rosana; Marchiori Edson; Souza Daniel Andrade Tinoco de

    2004-01-01

    Neste trabalho é relatado o caso de paciente do sexo masculino, de 38 anos de idade, que desenvolveu quadro de malária com comprometimento pulmonar. A tomografia computadorizada de alta resolução evidenciou espessamento de septos interlobulares e de bainhas peribroncovasculares, com áreas esparsas de atenuação em vidro fosco e de consolidações, além de derrame pleural bilateral, aspectos compatíveis com edema pulmonar. O paciente recebeu tratamento específico, evoluindo bem e tendo alta 11 di...

  6. First record of Hesperolabops nigriceps Reuter (Hemiptera: Miridae) on Opuntia ficus-indica in Milpa Alta, Mexico City.

    Science.gov (United States)

    Palomares-Pérez, Martín; Rodríguez-Leyva, Esteban; Brailovsky, Harry; Ramírez-Alarcón, Samuel

    2010-01-01

    In recent years a species of Hesperolabops has become a problem as a pest of nopalitos, Opuntia ficus-indica, in Milpa Alta, in the south of Mexico City, which is the most important production region of this vegetable in the country. A survey of Hesperolabops in Milpa Alta has resulted in the first report of Hesperolabops nigriceps Reuter. This occurrence should be monitored and considered in future studies in order to avoid misidentification of Hesperolabops spp. Kirkaldy native populations there, and to avoid the confusion of the damage that may be caused on O. ficus-indica.

  7. Manifestações e prevalência de bullyng entre alunos com altas habilidades/superdotação

    OpenAIRE

    Marcília de Morais Dalosto; Eunice Maria Lima Soriano de Alencar

    2013-01-01

    Este estudo teve como objetivo investigar o envolvimento de alunos com altas habilidades/superdotação com a prática de bullying, tendo como base os papéis assumidos por eles na condição de vítima, agressor e/ou testemunha. Participaram da pesquisa 118 alunos oriundos de escolas públicas (107) e escolas particulares (11) que frequentavam um programa para estudantes com altas habilidades/superdotação, oferecido pela Secretaria de Estado de Educação do Distrito Federal. Para a coleta de dados, f...

  8. Digestibilidad de garbanzo, maíz alta calidad proteica y frijol quebrado en tilapia Oreochromis niloticus

    OpenAIRE

    Montoya Mejía, Magnolia

    2014-01-01

    El garbanzo, maíz de alta calidad proteica y frijol quebrado, son cereales y leguminosas de gran producción en la región de Sinaloa, al momento de la cosecha algunos granos se quiebran y estos son considerados como granos de segunda, estos pueden ser utilizados como ingredientes en la formulación de alimentos balanceados para la acuicultura. El objetivo del presente trabajo fue determinar la digestibilidad de garbanzo, maíz de alta calidad proteica y frijol quebrado in vivo en ...

  9. Diseño de un programa de intervención con alumnos de altas capacidades: Optimismo

    OpenAIRE

    Martínez San José, Bárbara

    2015-01-01

    Este documento presenta un proyecto de intervención para favorecer el optimismo en alumnos con altas capacidades en edades comprendidas entre 12 y 16 años. En un primer momento se han expuesto los objetivos a conseguir con este trabajo. Seguidamente, se han definido con los conceptos de altas capacidades y de optimismo y sentido positivo. Así mismo, se ha explicado en qué contexto y que objetivos tendrá el programa de intervención de optimismo en sí, y se ha desarrollado con diversas activida...

  10. Perfil y necesidades de alumnos universitarios con altas capacidades en la Universidad de Málaga. Datos iniciales

    OpenAIRE

    Fernández Molina, Milagros

    2016-01-01

    La investigación sobre la presencia en las Universidad de alumnos con altas capacidades intelectuales es muy escasa, constituyendo un tema de estudio de importante proyección. Apenas hay publicaciones o informes sobre el acceso a los estudios superiores del alumnado con alta capacidad, el perfil personal e intelectual que presenta, las necesidades que tiene durante su trayectoria universitaria, la tasa de abandonos o de éxito en los estudios universitarios que elige, etc. En este trabajo se p...

  11. Transducer for Tension Force Measuring of Strip Materials

    Directory of Open Access Journals (Sweden)

    Emad S. Addasi

    2005-01-01

    Full Text Available In winding-up motor drive systems, such as that used in textile industry, it is very important to get a constant tension force for the winding strip material (thread and to reduce its oscillations. This study recommends a transducer with a special design to be used in the mentioned motor drive systems. By using a piston damper, spring, levers, slider and other simple components the suggested sensor (transducer can be used to control the motor speed for getting the required thread tension force. Also the suggested transducer avoids the disadvantage of other used conventional transducer: the parasitic (detrimental oscillations of the thread tension force, which affect the quality of the produced strip material.

  12. Molecular simulation of the surface tension of real fluids

    CERN Document Server

    Werth, Stephan; Hasse, Hans

    2016-01-01

    Molecular models of real fluids are validated by comparing the vapor-liquid surface tension from molecular dynamics (MD) simulation to correlations of experimental data. The considered molecular models consist of up to 28 interaction sites, including Lennard-Jones sites, point charges, dipoles and quadrupoles. They represent 38 real fluids, such as ethylene oxide, sulfur dioxide, phosgene, benzene, ammonia, formaldehyde, methanol and water, and were adjusted to reproduce the saturated liquid density, vapor pressure and enthalpy of vaporization. The models were not adjusted to interfacial properties, however, so that the present MD simulations are a test of model predictions. It is found that all of the considered models overestimate the surface tension. In most cases, however, the relative deviation between the simulation results and correlations to experimental data is smaller than 20 %. This observation corroborates the outcome of our previous studies on the surface tension of 2CLJQ and 2CLJD fluids where a...

  13. Uniaxial tension and tensile creep behaviors of EPS

    Institute of Scientific and Technical Information of China (English)

    康颖安; 李显方; 谭加才

    2008-01-01

    The mechanical behavior of EPS(Expanded polystyrene) with three densities at room temperature and under tension loading was studied.The results show that EPS material is characterized by brittle behavior in the tension tests,and tensile properties of EPS increase with the increase of density.Volume fraction has no a significant effect on the modulus of these foams.The tensile creep strain increases with stress for EPS with same density,indicating that the creep behavior is of the stress dependency.And the creep behavior of EPS exhibits density dependency,which the creep strain decreases with densities for a fixed stress value.Moreover the creep behavior under the constant tension load is well in coincidence with the three-parameter solid model.

  14. Uniaxial Tension Test of Slender Reinforced Early Age Concrete Members

    Directory of Open Access Journals (Sweden)

    Wenbo Zhang

    2011-08-01

    Full Text Available The present study aims to obtain the tensile properties of early age concrete based on a uniaxial tension test employing RC slender members. First, the paper shows that concrete strain is equal to the strain of rebar at the mid-span of the RC member. The tensile Young’s modulus and the strain capacity of early age concrete are estimated using strain measurements. The experiment indicated that the tensile Young’s modulus at an early age is higher than the compressive modulus. This observation was similar to one found in a previous investigation which used a direct tension test of early age concrete. Moreover, the paper describes how an empirical equation for mature concrete can be applied to the relation between uniaxial tensile strength and splitting tensile strength even in early age concrete. Based on a uniaxial tension test, the paper proposes an empirical equation for the relationship between standard bond stresses and relative slip.

  15. Dissipative Particle Dynamics of tension-induced membrane fusion

    DEFF Research Database (Denmark)

    Shillcock, Julian C.

    2009-01-01

    Recent studies of tension-induced membrane fusion using dissipative particle dynamics (DPD) simulations are briefly reviewed. The stochastic nature of the fusion process makes it necessary to simulate a large number of fusion attempts in order to obtain reliable fusion statistics and to extract...... meaningful values for the fusion probability and the average fusion times. All successful fusion events follow the same pathway. In this fusion pathway, configurations of individual lipids play an important role. Fusion starts with individual lipids assuming a splayed tail configuration with one tail......, three sub-processes have been identified in the fusion pathway. Their energy barriers are estimated to lie in the range 8-15kBT. The fusion probability is found to possess a maximum at intermediate tension values. As one decreases the tension, the fusion probability seems to vanish before...

  16. Membrane tension and peripheral protein density mediate membrane shape transitions

    Science.gov (United States)

    Shi, Zheng; Baumgart, Tobias

    2015-01-01

    Endocytosis is a ubiquitous eukaryotic membrane budding, vesiculation and internalization process fulfilling numerous roles including compensation of membrane area increase after bursts of exocytosis. The mechanism of the coupling between these two processes to enable homeostasis is not well understood. Recently, an ultrafast endocytosis (UFE) pathway was revealed with a speed significantly exceeding classical clathrin-mediated endocytosis (CME). Membrane tension reduction is a potential mechanism by which endocytosis can be rapidly activated at remote sites. Here, we provide experimental evidence for a mechanism whereby membrane tension reduction initiates membrane budding and tubulation mediated by endocytic proteins, such as endophilin A1. We find that shape instabilities occur at well-defined membrane tensions and surface densities of endophilin. From our data, we obtain a membrane shape stability diagram that shows remarkable consistency with a quantitative model. This model applies to all laterally diffusive curvature-coupling proteins and therefore a wide range of endocytic proteins.

  17. The critical tension in the 6D Cascading DGP model

    CERN Document Server

    Sbisa', Fulvio

    2014-01-01

    We investigate the presence of ghosts in the Cascading DGP model. We start by discussing the problem of the cosmological late time acceleration, and we introduce the modified gravity approach. We then focus on brane induced gravity models and in particular on the Cascading DGP model. We consider a specific realization of the latter model, and we study first order perturbations around pure tension solutions. In the scalar sector of a 4D scalar-vector-tensor decomposition, the dynamics on the 4D brane can be described by a master equation where a critical tension emerges in a suitable 4D limit. We give a geometrical interpretation of this critical tension, and explain its relevance for the presence of ghosts in the theory. We comment on the difference between our result and the one present in the literature, and stress its importance regarding the phenomenological viability of the model. We finally provide a numerical check which confirms the validity of our analysis.

  18. Phase behavior and interfacial tension studies of surfactant systems

    Energy Technology Data Exchange (ETDEWEB)

    Franses, E.I.

    1979-01-01

    Parallel studies of isomerically pure sodium P(1-heptylnonyl) benzene sulfoante, Texas No. 1, its mixture with sodium dodecyl sulfate (SDS), and the petroleum sulfonate TRS 10-80 were made. Phase behavior in water, in decane, and in water-decane mixtures was studied by spectroturbidimetry, polarizing light microscopy, ultracentrifugation, ultrafiltration, densitometry, conductimetry, low-frequency, 0.2 to 20 kHz, dielectric relaxation, isopiestic vapor pressure, and nuclear magnetic resonance spectroscopy. It was deduced that ultralow tensions (less than 0.01 dyn/cm) arise from the dispersed microcrystallites which form a third, usually liquid crystalline, phase at the decane-brine interfacial region. It appears that neither molecular adsorption from solution for micelles have anything to do with ultralow tensions, which appear to be sensitive to the third phase microstructure. The implications of these results for the mechanism of ultralow tensions in surfactant flooding processes for enhanced petroleum recovery are discussed.

  19. Energy conversion by surface-tension driven charge separation

    CERN Document Server

    Pini, Cesare; Dietzel, Mathias

    2016-01-01

    In this work, the shear-induced electrokinetic streaming potential present in free-surface electrolytic flows subjected to a gradient in surface tension is assessed. Firstly, for a Couette flow with fully resolved electric double layer (EDL), the streaming potential per surface stress as a function of the Debye parameter and surface potential is analyzed. By contrast to the Smoluchowski limit in pressure-driven channel flow, the shear-induced streaming potential vanishes for increasing Debye parameter (infinitely thin EDL), unless the free surface contains (induced) surface charge or the flow at the charged, solid wall is permitted to slip. Secondly, a technical realization of surface-tension induced streaming is proposed, with surface stress acting on the free (slipping) surfaces of a micro-structured, superhydrophobic wall. The streaming potential is analyzed with respect to the slip parameter and surface charge. Finally, the surface tension is assumed to vary with temperature (thermocapillarity) or with su...

  20. Birth and growth of cavitation bubbles within water under tension

    CERN Document Server

    Vincent, Olivier; Quinto-Su, Pedro A; Ohl, Claus-Dieter

    2011-01-01

    Water under tension, such as the water rising in tree vessels, is in a metastable state. Water cavitates spontaneously when the tension is high enough, as observed at equilibrium in the water filled holes of a drying hydrogel, called artifical trees. Here, in order to understand the dynamics of cavitation in tensed water, we directly trigger cavitation events, taking advantage of the disturbance generated by a focused laser pulse. We find that the inception of a bubble progresses in two stages. The first stage is ultra-fast, lasting less than microseconds, during which a bubble with a finite volume suddenly appears. This event relaxes the water tension, that we can therefore estimate. A second, slower stage follows when water diffuses into the surrounding medium.

  1. Modelling of tension stiffening for normal and high strength concrete

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1998-01-01

    Accurate calculations of the stiffness of concrete members are rare. Only in the uncracked state and the fully cracked state, where the reinforcement is near yielding, the stiffness calculations are relatively easy. The difficulties are due to the fact that concrete between cracks may give...... a substantial contribution to the stiffness, a phenomenon which is generally referred to as tension stiffening. The present paper describes a new theory of tension stiffening. It is based on a simple physical model for pure tension, which works with three different stages of crack generation. In a simplified...... form the model is extended to apply to biaxial stress fields as well. To determine the biaxial stress field, the theorem of minimum complementary elastic energy is used. The theory has been compared with tests on rods, disks, and beams of both normal and high strength concrete, and very good results...

  2. Contact Angles and Surface Tension of Germanium-Silicon Melts

    Science.gov (United States)

    Croell, A.; Kaiser, N.; Cobb, S.; Szofran, F. R.; Volz, M.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Precise knowledge of material parameters is more and more important for improving crystal growth processes. Two important parameters are the contact (wetting) angle and the surface tension, determining meniscus shapes and surface-tension driven flows in a variety of methods (Czochralski, EFG, floating-zone, detached Bridgman growth). The sessile drop technique allows the measurement of both parameters simultaneously and has been used to measure the contact angles and the surface tension of Ge(1-x)Si(x) (0 less than or equal to x less than or equal to 1.3) alloys on various substrate materials. Fused quartz, Sapphire, glassy carbon, graphite, SiC, carbon-based aerogel, pyrolytic boron nitride (pBN), AIN, Si3N4, and polycrystalline CVD diamond were used as substrate materials. In addition, the effect of different cleaning procedures and surface treatments on the wetting behavior were investigated. Measurements were performed both under dynamic vacuum and gas atmospheres (argon or forming gas), with temperatures up to 1100 C. In some experiments, the sample was processed for longer times, up to a week, to investigate any changes of the contact angle and/or surface tension due to slow reactions with the substrate. For pure Ge, stable contact angles were found for carbon-based substrates and for pBN, for Ge(1-x)Si(x) only for pBN. The highest wetting angles were found for pBN substrates with angles around 170deg. For the surface tension of Ge, the most reliable values resulted in gamma(T) = (591- 0.077 (T-T(sub m)) 10(exp -3)N/m. The temperature dependence of the surface tension showed similar values for Ge(1-x)Si(x), around -0.08 x 10(exp -3)N/m K, and a compositional dependence of 2.2 x 10(exp -3)N/m at%Si.

  3. Calcitonin Gene-Related Peptide in Tension-Type Headache

    Directory of Open Access Journals (Sweden)

    M. Ashina

    2002-01-01

    Full Text Available In the last 10 years there has been increasing interest in the role of calcitonin gene-related peptide (CGRP in primary headaches. Tension-type headache is one of the most common and important types of primary headaches, and ongoing nociception from myofascial tissues may play an important role in the pathophysiology of this disorder. CGRP sensory fibers are preferentially located in the walls of arteries, and nerve fibers containing CGRP accompany small blood vessels in human cranial muscles. It is well established that nociception may lead to release of CGRP from sensory nerve endings and from central terminals of sensory afferents into the spinal cord. It has also been shown that density of CGRP fibers around arteries is increased in persistently inflamed muscle. These findings indicate that ongoing activity in sensory neurons in the cranial muscles may be reflected in changes of plasma levels of neuropeptides in patients with chronic tension-type headache. To explore the possible role of CGRP in tension-type headache, plasma levels of CGRP were measured in patients with chronic tension-type headache. This study showed that plasma levels of CGRP are normal in patients and unrelated to headache state. However, the findings of normal plasma levels of CGRP do not exclude the possibility that abnormalities of this neuropeptide at the neuronal or peripheral (pericranial muscles levels play a role in the pathophysiology of tension-type headache. Investigation of CGRP in other compartments with new sensitive methods of analysis is necessary to clarify its role in tension-type headache.

  4. Tensions between State and Market in Chile: Educational Policy and Culture

    Directory of Open Access Journals (Sweden)

    Ann Matear

    2007-10-01

    Full Text Available Since 1990, education has been the focus of policy  initiatives relating to national development, and  public investment has increased. However, highquality education remains an elusive aspiration for  the majority of children, and the educational ‘good’  which is distributed is far from standard in Chile.  The achievement gap between income groups and  between the different school types is widening and  confidence in the public education system is falling. This article analyses the tensions inherent in  implementing policies that aim to promote equity  within a market-oriented education system, supported by a legislative framework that constrains  policy changes that might depart from a neoliberal  model. It examines how the provision and financing of education have become increasingly privatized; how student enrolment has shifted dramatically from state to privately-run schools; and how  parental choice in education is contributing to the  growing stratification of the education system by  social class. Resumen: Tensiones entre el estado y el Mercado en Chile: políticas educativas y culturaDesde 1990, la educación ha sido el foco de las  iniciativas de la política referente al desarrollo  nacional y la inversión pública ha aumentado. Sin  embargo, una educación de alta calidad sigue  siendo una aspiración evasiva para la mayoría de  niños y el ‘bien educativo’ que se distribuye está  lejos de ser estandarizado en Chile. La brecha del  logro entre los grupos socioeconómicos y entre los  diversos tipos de escuela se está ensanchando y la  confianza en el sistema educativo público está  bajando. Este artículo analiza las tensiones inherentes a la hora de implementar políticas que  apunten a promover la equidad dentro de un sistema educativo orientado hacia el libre mercado,  apoyado por un marco legislativo que restringe los  cambios de política que pudieran salirse del modelo neoliberal

  5. Why is surface tension a force parallel to the interface?

    CERN Document Server

    Marchand, Antonin; Snoeijer, Jacco H; Andreotti, Bruno

    2012-01-01

    A paperclip can float on water. Drops of mercury refuse to spread on a surface. These capillary phenomena are macroscopic manifestations of molecular interactions, and can be explained in terms of surface tension. For students, the concept of surface tension is quite challenging since the microscopic intuition is often in conflict with the common macroscopic interpretations. In this paper we address a number of conceptual questions that are often encountered when teaching capillarity. By answering these questions we provide a perspective that reconciles the macroscopic viewpoints, from thermodynamics or fluid mechanics, and the microscopic perspective from statistical physics.

  6. Line-Tension Controlled Mechanism for Influenza Fusion

    OpenAIRE

    Herre Jelger Risselada; Giovanni Marelli; Marc Fuhrmans; Smirnova, Yuliya G.; Helmut Grubmüller; Siewert Jan Marrink; Marcus Müller

    2012-01-01

    Our molecular simulations reveal that wild-type influenza fusion peptides are able to stabilize a highly fusogenic pre-fusion structure, i.e. a peptide bundle formed by four or more trans-membrane arranged fusion peptides. We rationalize that the lipid rim around such bundle has a non-vanishing rim energy (line-tension), which is essential to (i) stabilize the initial contact point between the fusing bilayers, i.e. the stalk, and (ii) drive its subsequent evolution. Such line-tension controll...

  7. Physics, cosmology and astronomy, 1300 - 1700: tension and accommodation.

    Science.gov (United States)

    Unguru, S.

    The present volume has its origins in a spring 1984 international workshop, held in Tel-Aviv, Israel. It deals with the interrelationships between physics, cosmology and astronomy between 1300 and 1700, with the tensions between the subjects and with the resolution of that tension in the new science which came to supplant medieval philosophy. It also covers the ancient background and includes chapters on Islamic and Jewish contributions, as well as on optics, science and religion, natural philosophy and mathematics, and science and political power.

  8. Surface tension in plasmas related to double layer formation

    International Nuclear Information System (INIS)

    Self-organized space charge configurations bordered by electric double layers appear in plasma as the result of the transition into a state characterized by local minimum of the free energy. Considering the self-assemblage process of such a complex well-confined space-charge configuration in plasma, known by the name of ball of fire, as a nucleation process, it becomes possible to define an equivalent surface tension for the double layer that covers the core of the ball of fire and to make some predictions for its surface tension coefficient and capacitance. (author)

  9. Softening of edges of solids by surface tension.

    OpenAIRE

    Mora, Serge; Pomeau, Yves

    2015-01-01

    Surface tension tends to minimize the area of interfaces between pieces of matter in different thermodynamic phases, be they in the solid or the liquid state. This can be relevant for the macroscopic shape of very soft solids, and lead to a roughening of initially sharp edges. We calculate this effect for a neo-Hookean elastic solid, with assumptions corresponding to actual experiments, namely the case where an initially sharp edge is rounded by the effect of surface tension felt when the flu...

  10. Linearized gravity in flat braneworlds with anisotropic brane tension

    CERN Document Server

    Ito, M

    2002-01-01

    We study the four-dimensional gravitational fluctuation on anisotropic brane tension embedded in braneworlds with vanishing bulk cosmological constant. In this setup, warp factors have two types (A and B) and we point out that the two types correspond to positive and negative tension brane, respectively. We show that volcano potential in the model of type A has singularity and the usual Newton's law is reproduced by the existence of normalizable zero mode. While, in the case of type B, the effective Planck scale is infinite so that there is no normalizable zero mode.

  11. Flat 3-Brane with Tension in Cascading Gravity

    CERN Document Server

    de Rham, Claudia; Tolley, Andrew J

    2009-01-01

    In the Cascading Gravity brane-world scenario, our 3-brane lies within a succession of lower-codimension branes, each with their own induced gravity term, embedded into each other in a higher-dimensional space-time. In the 6+1-dimensional version of this scenario, we show that a 3-brane with tension remains flat, at least for sufficiently small tension that the weak-field approximation is valid. The bulk solution is nowhere singular and remains in the perturbative regime everywhere.

  12. Surface tension of liquid metals and alloys--recent developments.

    Science.gov (United States)

    Egry, I; Ricci, E; Novakovic, R; Ozawa, S

    2010-09-15

    Surface tension measurements are a central task in the study of surfaces and interfaces. For liquid metals, they are complicated by the high temperatures and the consequently high reactivity characterising these melts. In particular, oxidation of the liquid surface in combination with evaporation phenomena requires a stringent control of the experimental conditions, and an appropriate theoretical treatment. Recently, much progress has been made on both sides. In addition to improving the conventional sessile drop technique, new containerless methods have been developed for surface tension measurements. This paper reviews the experimental progress made in the last few years, and the theoretical framework required for modelling and understanding the relevant physico-chemical surface phenomena.

  13. String and Brane Tensions as Dynamical Degrees of Freedom

    CERN Document Server

    Guendelman, E I; Nissimov, Emil R; Pacheva, S; Guendelman, Eduardo; Kaganovich, Alexander; Nissimov, Emil; Pacheva, Svetlana

    2002-01-01

    We discuss a new class of string and p-brane models where the string/brane tension appears as an additional dynamical degree of freedom instead of being introduced by hand as an ad hoc dimensionfull scale. The latter property turns out to have a significant impact on the string/brane dynamics. The dynamical tension obeys Maxwell (or Yang-Mills) equations of motion (in the string case) or their rank p gauge theory analogues (in the p-brane case), which in particular triggers a simple classical mechanism of (``color'') charge confinement.

  14. Surface tension in microsystems engineering below the capillary length

    CERN Document Server

    Lambert, Pierre

    2013-01-01

    This book describes how surface tension effects can be used by engineers to provide mechanical functions in miniaturized products (<1 mm). Even if precursors of this field such as Jurin or Laplace already date back to the 18th century, describing surface tension effects from a mechanical perspective is very recent.The originality of this book is to consider the effects of capillary bridges on solids, including forces and torques exerted both statically and dynamically by the liquid along the 6 degrees-of-freedom.It provides a comprehensive approach to various applications, such as capillary ad

  15. Spacetime structure of 5D hypercylindrical vacuum solutions with tension

    CERN Document Server

    Cho, Inyong; Kim, Sang Pyo; Lee, Chul H

    2007-01-01

    We investigate geometrical properties of 5D cylindrical vacuum solutions with a transverse spherical symmetry. The metric is uniform along the fifth direction and characterized by tension and mass densities. The solutions are classified by the tension-to-mass ratio. One particular example is the well-known Schwarzschild black string which has a curvature singularity enclosed by a horizon. We focus mainly on geometry of other solutions which possess a naked singularity. The light signal emitted by an object approaching the singularity reaches a distant observer with finite time, but is infinitely red-shifted.

  16. Nonlocal Theory to Analyse Nanotube Structures under Tension

    Directory of Open Access Journals (Sweden)

    Hamidreza Yazdani Sarvestani

    2015-01-01

    Full Text Available Because nanocomposites have found augmented use in many industries, the analytical solutions are required to be developed. This paper presents the development of a new analytical method for studying nanotube structures under tension using layer-wise and Eringen theories. Two opposite ends of tubes are subjected to normal forces. Nonlocal governing differential equations are derived and presented. The theoretical developments determine the effect of the geometric and nonlocal constitutive relations for single-walled nanotubes (SWNTs, double-walled nanotubes (DWNTs, and multiwalled nanotubes (MWNTs under tension loading. It is observed that all displacement components increase with the increase in the nonlocal parameter.

  17. Flat 3-brane with Tension in Cascading Gravity

    International Nuclear Information System (INIS)

    In the cascading gravity brane-world scenario, our 3-brane lies within a succession of lower-codimension branes, each with their own induced gravity term, embedded into each other in a higher-dimensional space-time. In the (6+1)-dimensional version of this scenario, we show that a 3-brane with tension remains flat, at least for sufficiently small tension that the weak-field approximation is valid. The bulk solution is singular nowhere and remains in the perturbative regime everywhere.

  18. Is nonstandard interaction a solution to the three neutrino tensions?

    CERN Document Server

    Fukasawa, Shinya; Yasuda, Osamu

    2016-01-01

    In this work we present a scenario in which a nonstandard interaction in neutrino propagation can explain the three major tensions in the neutrino oscillation data at present. These tensions are: (i) a non-zero best-fit value of the non-standard oscillation parameters in the the global analysis of the solar and KamLAND data which rules out the standard oscillation scenario at $90\\%$ C.L, (ii) the measurement of the non-maximal value of $\\theta_{23}$ by NO$\

  19. Phenylephrine Decreases Vascular Tension in Goat Arteries in Specific Circumstances.

    Directory of Open Access Journals (Sweden)

    Renu R Raj

    Full Text Available Phenylephrine (PE causes vasoconstriction through alpha adrenergic receptors. PE-induced vasodilatation has also been reported earlier in pre-constricted vessels. Here we demonstrate in spiral strips of goat arteries that addition of PE can decrease tone even from base-line levels (i.e. not pre-constricted and show that this process requires nitric oxide (NO and alpha adrenergic stimulation, but is cGMP-independent. Under control conditions, PE caused vasoconstriction, but under conditions where NO levels are higher, as with L-Arginine or sodium nitroprusside, PE decreased vessel tension. L-Arginine/PE combination was not able to decrease tension when alpha adrenoceptors were blocked with Phentolamine or endothelial nitric oxide synthase (eNOS was blocked with Nω-Nitro-L-arginine (L-NNA. Propranolol, a beta blocker, was unable to prevent the reduction in tension by the L-Arginine/PE combination. Adrenaline and noradrenaline (and not isoproterenol also reduced vessel tension in the presence of L-Arginine. Even when NO levels were not enhanced, relieving NO from having to stimulate the enzyme soluble guanylyl cyclase (sGC (either by using sGC blockers, namely ODQ or methylene blue, or by enhancing cGMP levels (with sildenafil which by negative feedback probably inhibits sGC led to PE-induced reduction of vascular tension. PMA-phorbol myristate acetate-an agonist which stimulates Protein Kinase C was able to prevent the ability of PE to reduce vascular tension in a high NO environment. Our conclusion is that PE reduces vascular tension through alpha adrenoceptors if there is excess NO availability to activate a putative pathway. Though the reduction of vessel tone by PE is dependent on NO, it is independent of cGMP. Prior treatment with PMA or PE itself can prevent further PE-induced reduction of tension in a high NO environment. The results here suggest, counter-intuitively, that alpha blockers may be of help in the treatment of septic shock

  20. The Yarn Curve and Tension in Rotor Spinning

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effective way of finding the yarn curve shape and tension of OE(open end) yarn inside the rotor is carried out and treated by dividing the yarn curve into two parts, from which the trajectory of the yarn sliding on the navel surface is also obtained. It is pointed out that the yarn curve shape and tension will both fluctuate with the trajectory's revolving cycle inside the rotor. However, the fluctuation is not too great, so the motion can still be regarded as approximately steady for dynamic analysis.

  1. A expansão da consciência e a alta frequência cerebral

    OpenAIRE

    Moura, Gilda

    2002-01-01

    O estudo clínico e eletroencefalográfico das pessoas que vivem experiências excepcionais, quer relacionado a fenômenos de cura, paranormalidade, ingestão de psicoativos ou a fenômenos associados aos OVNIS, nos levou a encontrar uma onda Beta de 40 Hz, como o elo de ligação entre todos os fenômenos. Além dessa constatação verificou-se nas pessoas pertencentes ao grupo com experiência com o fenômeno OVNI, uma onda Beta de fequência ainda mais alta ou Gama, localizada nos frontais e associada a ...

  2. La arquitectura de los despoblados moriscos en los valles de la Marina Alta.

    OpenAIRE

    SOLER ESTRELA, ALBA

    2009-01-01

    La tesis realiza el estudio arquitectónico de los núcleos de población de origen islámico y mudéjar, que quedaron abandonados tras la expulsión de los moriscos, en el ámbito geográfico de los Valles de la Marina Alta (Alicante). El método desarrollado se inscribe en la línea de los estudios e investigaciones relacionadas con el conocimiento para la conservación del patrimonio arquitectónico. A partir de una lectura arquitectónica basada en la observación directa de las edificaciones se realiz...

  3. Estudio de la fiabilidad mediante ensayos acelerados de diodos ultravioletas de alta potencia

    OpenAIRE

    Segura Antúnez, César

    2014-01-01

    Durante los últimos años la utilización de los LEDs (Light Emitting Diodes) ha aumentado de forma muy importante siendo hoy en día una alternativa real a los sistemas de iluminación tradicionales. La iluminación basada en LEDs se está utilizando ampliamente en automoción, arquitectura, aplicaciones domésticas y señalización debido a su alta fiabilidad, pequeño tamaño y bajo consumo. La evaluación de la fiabilidad de los LEDs es un tema clave previo a la comercialización o a la puesta en...

  4. Tránsito de la onda de choque en canales de alta pendiente

    OpenAIRE

    MONTOYA V., JUAN DAVID; TORO B., MAURICIO; CARVAJAL S., LUIS FERNANDO; VÉLEZ U., JAIME IGNACIO

    2009-01-01

    El presente trabajo investiga la aplicación del tránsito de la onda cinemática con ajuste de la onda de choque en el caso del tránsito hidráulico (unidimensional) en canales de alta pendiente; se considera éste como un primer acercamiento al tema del tránsito de ondas o hidrógrafas de rápido crecimiento, asociadas al rompimiento de presas o a eventos hidrológicos extremos. Bajo esta premisa se pretende implementar una teoría hidráulica que aproxime una solución numérica al tránsito de flujo...

  5. Transito de la onda de choque en canales de alta pendiente

    OpenAIRE

    Montoya Velilla, Juan David; Toro Botero, Francisco Mauricio; Carvajal Serna, Luis Fernando; Vélez Upegui, Jaime Ignacio

    2006-01-01

    El presente trabajo investiga la aplicación del tránsito de la onda cinemática con ajuste de la onda de choque en el caso del tránsito hidráulico (unidimensional) en canales de alta pendiente; se considera éste como un primer acercamiento al tema del tránsito de ondas o hidrógrafas de rápido crecimiento, asociadas al rompimiento de presas o a eventos hidrológicos extremos. Bajo esta premisa se pretende implementar una teoría hidráulica que aproxime una solución numérica al tránsito de flujo n...

  6. Firing with compressed air at very high pressure; Disparo con aire comprimido a muy alta presion

    Energy Technology Data Exchange (ETDEWEB)

    Saez Garcia, E.; Margareto Garcia, J.L.; Millan Echevarria, J.L.; Embil Martinez, E. [Escuela Tecnia Superior de Ingenieros Mineros, Oviedo (Spain)

    1994-05-01

    This article recounts the experiments executed in Hunosa`s Montsacro pit on the application of the DAMAP (Disparo can aire comprimido a muy alta presion - Firing with compressed air at very high pressure) process to the horizontal, sloping and caving seams or horizontal sublevels mining method usually used by Hunosa for thick and vertical seams. The project met the approval of Ocicarbon who participated with finance. Mescek Coal Mines also participated with their knowledge of DAMAP from mining in Hungary and provided the necessary equipment, technical assistance and training for Hunosa personnel. The project lasted for 14 months, comprising three phases: receipt, assembling of the equipment, and two months of system testing; 10 months of experiments to discern the possibilities offered by DAMAP technology in horizontal sublevels; and compilation of a report recounting the experience and results of the project. 3 figs., 1 tab.

  7. Organic agriculture in the municipality of Alta Floresta-MT: case study on family based properties

    Directory of Open Access Journals (Sweden)

    Inês Caroline de Lima Proença

    2016-08-01

    Full Text Available Family farming has distinct characteristics in their organization and reproduction, such as the use of labor, family labor, the smallest territorial dimension of the plant and crop diversity. Organic agriculture has great potential for family farms, establishing more harmonious relationships between natural ecosystems and agricultural activities. In this context, this paper aims to study five units of organic farming family based in the municipality of Alta Floresta, state of Mato Grosso, making the general characterization of it and trying to identify the reality and the difficulties faced by these farmers. Data were made from semi-structured interviews and observation. It was found that the lack of technical assistance, the lack of access to rural credit facilities and lack of family labor are limiting factors that directly interfere with the management of agroecosystems. Furthermore, the great diversity of species managed is a key success factor in seeking and maintaining the stability of agroecosystems.

  8. Amplificador de potencia de alta eficiencia en la banda de 2.6 GHz

    OpenAIRE

    Mendiguchia Gutiérrez, Hugo

    2015-01-01

    La evolución hacia formatos de modulación digital con altas tasas de transmisión de datos por unidad de ancho de banda, típica de las nuevas generaciones de sistemas de comunicaciones inalámbricas (el caso de 4G), impone fuertes requisitos de linealidad en el diseño de los esquemas de transmisión. La manipulación sin distorsión de señales con una envolvente muy variable y valores para su relación potencia pico a potencia promedio (PAPR de sus siglas en inglés) tan altos como 10 dB, impone ade...

  9. Photoelectrochemical evidence of nitrogen incorporation during anodizing sputtering--deposited Al-Ta alloys.

    Science.gov (United States)

    Zaffora, A; Santamaria, M; Di Franco, F; Habazaki, H; Di Quarto, F

    2016-01-01

    Anodic films were grown to 20 V on sputtering-deposited Al-Ta alloys in ammonium biborate and borate buffer solutions. According to glow discharge optical emission spectroscopy, anodizing in ammonium containing solution leads to the formation of N containing anodic layers. Impedance measurements did not evidence significant differences between the dielectric properties of the anodic films as a function of the anodizing electrolyte. Photoelectrochemical investigation allowed evidencing that N incorporation induces a red-shift in the light absorption threshold of the films due to the formation of allowed localized states inside their mobility gap. The estimated Fowler threshold for the internal photoemission processes of electrons resulted to be independent of the anodizing electrolyte confirming that N incorporation does not appreciably affect the density of states distribution close to the conduction band mobility edge. The transport of photogenerated carriers has been rationalized according to the Pai-Enck model of geminate recombination.

  10. [The prevention of caries in Alta Val di Cecina--Volterra: a longitudinal study].

    Science.gov (United States)

    Benetti, G L; Dini, M; Rossetti, L

    1993-01-01

    The authors present the results of three years' activity relating to "caries' prevention" in comparison with data concerning the research of previous five years. The average and standard deviations of DMFT values with regard to the permanent teeth and dmft concerning the deciduous ones, obtained from the dental visit of 222 children attending the 1st and the 3rd class of the primary school and 1st class of the secondary school, has demonstrated a statistically significant reduction of caries, compared with data concerning 749 pupils of the same standards in the period from 1984 to 1988. This fact confirms that the programme defined by U.S.L. n. 15 "Alta Val di Cecina", including sanitary education for children of primary school with their parents and teachers, besides dental examinations to the filter classes, is a valid instrument to obtain the reduction of carious' pathology in evolutive age. PMID:8265461

  11. Viceregal furniture from Oaxaca carried out in zumaque. The marquetry of Villa Alta

    Directory of Open Access Journals (Sweden)

    Corrales, Juan Manuel

    2011-06-01

    Full Text Available During the Viceregal period, the Mexican region of Oaxaca was a major furniture production center. Among the diverse Oaxacan works those executed in a technique specific to the mountain region commonly known as zumaque stand out. These pieces made in the Villa Alta de San Ildefonso during the 17th to 19th centuries are limited to certain types of civil furniture: writing desks, papeleras, little desks and chests for female use, coffers, little chests and boxes. This article offers the most recent and complete research on the subject and deals with the problematic terminology, the origins of this production center, the diverse construction and decorative techniques utilized and the analytic study of the wood and fillers employed.La región mexicana de Oaxaca, durante el periodo virreinal, fue un gran centro productor de muebles. De entre los diversos trabajos oaxaqueños destacan los realizados con una técnica particular de la zona serrana denominada, comúnmente, zumaque. Estas producciones realizadas en la Villa Alta de San Ildefonso, entre los siglos XVII al XIX, se limitan exclusivamente a ciertas tipologías de muebles civiles; escritorios, papeleras, escritorillos o arquillas de estrado, arcas, arquetas y cajas. Este artículo presenta la investigación más reciente y completa sobre el tema adentrándose en la problemática terminológica, los orígenes del centro productor, las diversas técnicas constructivas y decorativas empleadas así como el estudio analítico de sus maderas y la pasta de relleno.

  12. Etnoarcheologia dei paesaggi alpini di alta quota nelle Alpi occidentali: un bilancio preliminare

    Directory of Open Access Journals (Sweden)

    Francesco Carrer

    2015-12-01

    Full Text Available Lo studio dell’interazione tra gruppi umani e ambiente montano è centrale nell’attuale ricerca archeologica. L’etnoarcheologia contribuisce analizzando questa interazione nei contesti moderni e contemporanei, con lo scopo di creare modelli analogici per interpretare il passato e di comprendere più a fondo le strategie umane storiche e attuali. Il progetto EthWAL (Etnoarcheologia dei paesaggi alpini di alta quota nelle Alpi occidentali, nato nel 2013, si pone come punto di riferimento per lo studio delle attività umane nelle alte quote alpine in epoca moderna e contemporanea. È un progetto multidisciplinare (unisce i metodi archeologici a quelli etnografici e storiografici, alle analisi spaziali e alle analisi dei suoli e multiscalare (dalla piccola alla grande scala. Particolare attenzione è data alle capanne pastorali tradizionali. I risultati di questo progetto saranno utili all’archeologia e permetteranno la valorizzazione delle caratteristiche culturali dei paesaggi di alta montagna. The study of the interaction between human groups and mountain environment is crucial for archaeological research. Ethnoarchaeology contributes the analysis of this interaction in modern and contemporary contexts, aimed at creating analogical models for interpreting the past and understanding human strategies in historical and modern periods. The EthWAL project (Ethnoarchaeology of Western Alpine upland Landscapes, started in 2013, and aims to be a reference for the study of human activities in the alpine uplands during the modern and contemporary age. This is a multidisciplinary (associating archaeological methods to ethnography, historiography, spatial analysis and soil analysis and multiscalar project (small to large scale. Specific attention is given to traditional pastoral huts. The results of this project will be useful for archaeology and contribute to the management of cultural heritage in high altitude landscapes.

  13. Impacto de la regulación ambiental en las actividades de la alta gerencia corporativa

    Directory of Open Access Journals (Sweden)

    Rina Tigrera Carneiro

    2003-09-01

    Full Text Available El presente ensayo tiene por finalidad exponer algunas consideraciones y reflexiones acerca del impacto que ha generado la regulación ambiental en las actividades de la alta gerencia corporativa. Para tal fin, fue necesario realizar una revisión documental de las distintas bibliografías, documentos y escritos especializados en el área, tanto en el ámbito nacional como latinoamericano; la cual, permitió llegar a las siguientes conclusiones: la introducción de las distintas regulaciones de índole ambiental y la variable ambiente han causado en el ámbito corporativo y en su alta dirección cambios significativos en la forma de hacer negocios. Dichos cambios, requieren actividades gerenciales desarrolladas con tecnologías verdes que sean capaces de prevenir problemas ambientales a través de estrategias de producción, operabilidad y funcionamiento menos lesivas, lo cual supone por un lado, un sustancial desembolso, que tal vez, muchas organizaciones no estén en capacidad de sufragar; y por otra, una forma de alcanzar ventaja competitiva que influirían decisivamente en la imagen corporativa, en la calidad del producto, su costo, comercialización y exportación. De igual manera, la inserción de la dimensión ambiente, debe implicar para la gerencia un nuevo estado de conciencia que sea la guía que geste transformaciones profundas en patrones de conductas, valores, aptitudes y afectos que propicien un rol ecológico ambientalista en lo interno y externo de la empresa y por ende en la comunidad global.

  14. Cultivo de cachama blanca en altas densidades y en dos sistemas cerrados

    Directory of Open Access Journals (Sweden)

    Germán Poleo

    2011-04-01

    Full Text Available El objetivo de este trabajo fue evaluar la tolerancia de la cachama blanca, Piaractus brachypomus, a cultivos en altas densidades en sistemas cerrados. Novecientos alevines de 44,3±26 g de peso, se distribuyeron en seis tanques de concreto, con 4,8 m³ de agua. Tres tanques presentaron cero recambio de agua (SCR, y en otros tres, el agua se hizo circular a través de un bioclarificador (SRA. Ambos tratamientos presentaron fuerte aireación para mantener los sólidos en suspensión y suministrar aire. Los peces se alimentaron a saciedad con pienso comercial por 192 días. Los parámetros de calidad de agua como: oxígeno disuelto, amonio total, nitritos, nitratos, alcalinidad, dureza, temperatura y pH, se midieron semanalmente. Los peces en el SCR crecieron a una tasa de 2,34±0,05 g por día, y tuvieron conversión alimenticia de 1,5±0,06, densidad final de 12,96±0,53 kg m-3, y peso final de 449,5±99 g. En el SRA, los peces crecieron 2,33±0,03 g por día, con conversión alimenticia de 1,6±0,07, densidad final de 12,13±1,12 kg m-3, y peso final de 446,5±10 g. La cachama blanca puede ser cultivada en sistemas cerrados con cero recambio de agua en altas densidades.

  15. Surface tension of calcium hydroxide associated with different substances Tensão superficial do hidróxido de cálcio associado a diferentes substâncias

    Directory of Open Access Journals (Sweden)

    Carlos Estrela

    2005-06-01

    Full Text Available The purpose of this study was to evaluate the surface tension of calcium hydroxide (CH associated with different substances (deionized distilled water, camphorated paramonochlorophenol, 2% chlorhexidine digluconate, Otosporin, 3% sodium lauryl ether sulphate; Furacin, PMC Furacin using tensiometer. The action of the substances studied on the dentinal structure enhances the property of surface tension. This method consists in the application of force to separate a platinum ring immersed in the substances. Thus, torsion was applied to the screw until the platinum ring separated during substances testing. Considering the methodology applied, the following can be concluded: distilled water alone or associated with CH presented a high surface tension (70.00 and 68.40 dynes/cm; calcium hydroxide in association with anionic detergent showed low surface tension (31.60 dynes/cm; camphorated paramonochlorophenol plus CH presented low surface tension (37.50 dynes/cm; 2% chlorhexidine associated with calcium hydroxide showed high surface tension values (58.00 dynes/cm; Otosporin plus calcium hydroxide showed low surface tension (35.40 dynes/cm; paramonochlorophenol Furacin mixed with calcium hydroxide presented surface tension equal to 45.50 dynes/cm; sodium hypochlorite presented high surface tension (75.00 dynes/cm. Antimicrobial agents more indicated in endodontics, i.e. CH, chlorhexidine and hypochlorite, presented the highest surface tension.Estudou-se a tensão superficial do hidróxido de cálcio associado a diferentes substâncias (água destilada deionizada, paramonoclorofenol canforado, digluconato de clorexidina 2%, Otosporin, sulfato éter lauril sódio 3%, furacin, PMC furacin usando tensiômetro. O modelo experimental consistiu na aplicação de uma força para separar um anel de platina imerso na superfície das substâncias, exercido por um tensiômetro. Considerando a metodologia aplicada, pode-se concluir: a água destilada isolada ou

  16. Caracterización de la integridad de las superficies maquinadas a altas velocidades en el acero 40XHMA//Characterization of surface integrity of machined surfaces at high cutting speed in 40XHMA steel

    Directory of Open Access Journals (Sweden)

    Mario Jacas-Cabrera

    2013-05-01

    Full Text Available Este trabajo tiene como objetivo el estudio de la integridad superficial de la superficie maquinada a altas velocidades de corte en el acero 40XHMA. Los experimentos fueron realizados en un proceso de torneado utilizando regímenes de corte correspondientes a un proceso de acabado. Una vez maquinadaslas probetas, se le realizaron ensayos de rugosidad superficial, tensiones residuales, microdureza Vickers y análisis de la deformación superficial. Como resultado se demostró que la variación de valores de la velocidad de corte no tuvo un efecto significativo en los valores de rugosidad superficial, observándoseuna ligera tendencia a la disminución de la misma, a medida que la velocidad de corte aumenta. En las muestras analizadas no se observaron zonas de deformación plástica superficial, pero sin embargo, se observó un incremento de la microdureza Vickers en la superficie maquinada, así como una disminuciónde las tensiones residuales al aumentar las velocidades de corte.Palabras claves: integridad superficial, maquinado a altas velocidades de corte, acero 40XHMA, acero 4340._______________________________________________________________________________AbstractThis work aims at the study of surface integrity on machined surfaces at high cutting speeds of the 40XHMA steel. The experiments were performed in a turning process with cutting schemes corresponding to polishing: Once machined, the specimens were subjected to different types of analysis: surface roughness, residual stresses, micro Vickers hardness and analysis of surface deformation .As a result it was shown that the variation of cutting speed had no significant effect on surface roughness values, showing a slight tendency to decrease it. In the tested samples zones of surface plastic-deformation were not observed. Nonetheless the micro Vickers hardness showed an increment in the machined surface anda decrease in residual stress with increasing cutting speeds was observed as well

  17. Decision 2010-021 : TransAlta Wind Ardenville wind plant and substation : application no. 1604970, proceeding ID 260

    International Nuclear Information System (INIS)

    TransAlta Wind, a wholly owned subsidiary of TransAlta Corporation, filed an application in April 2009 to construct and operate the Ardenville wind farm and substation in Alberta. The wind farm consists of 23 wind turbines, each rated at 3 MW, for a total installed capacity of 69 MW. The wind farm would be connected to the Alberta Interconnected Electric System at the substation. TransAlta anticipates that a new 138-kV transmission line will be required and has contacted the transmission facilities for the future applications. The Alberta Utilities Commission issued a notice to all interested parties and landholders within 2 km of the proposed wind farm. Two residents raised concerns regarding the use of fossil fuels and alternative fuels, ecological impacts and aesthetic impacts of wind farms and land values. Upon review of information, the Commission was satisfied that approval of the application was in the public interest and that the wind farm complies with all regulatory requirements, including sound levels. Pursuant to sections 11, 14 and 15 of the Hydro and Electric Energy Act, the Commission approved the application and granted approval to TransAlta Wind to construct and operate the Ardenville wind power plant and substation.

  18. Cytological mechanisms of interspecific incrossability and hybrid sterility between Oryza sativa L. and O.alta Swallen

    Institute of Scientific and Technical Information of China (English)

    FU XueLin; LU YongGen; LIU XiangDong; Li JinQuan; Feng JiuHuan

    2007-01-01

    Oryza sativa and O. alta belong to AA and CCDD genomes in Oryza, respectively. Interspecific reproductive isolation limits the transfer of favorable genes from O. alta into O. sativa. The cytological mechanisms of interspecific incrossability and hybrid sterility between O. sativa and O. alta were studied systematically in this paper. We indentified two cytological causes of interspecific incrossability. First, we observed embryo sac incompatibility that caused fertilization barriers of variable severity such as non-fertilization, fertilization stagnation and egg cell single-fertilization. Second, we observed hybrid inviability, the major cause for incrossability, apparent from hybrid embryo developmental stagnation and embryo abortion. Hybrid sterility included both embryo sac sterility and pollen sterility.The hybrid embryo sac was completely sterile and exhibited mainly embryo sac degeneration. Hybrid pollen was also sterile and mainly typical abortive. Hybrid sterility was mainly caused by severely abnormal meioses of megasporocytes and pollen mother cells; it is the most important abnormality, being chromosome sterility. Several methods are suggested to overcome the interspecific reproductive isolation between O. sativa and O. alta.

  19. Seguimiento de pacientes dados de alta de un hospital de día para adolescentes.Estudio descriptivo.

    Directory of Open Access Journals (Sweden)

    Rubén D Gualtero

    2007-01-01

    Full Text Available Estudio descriptivo del Hospital de Día para Adolescentes de Gavà (Barcelona a partir de una encuesta ad hoc que se administró al ingreso, al alta y, posteriormente, a los seis meses y al año.

  20. [Asthenic disorders and cognitive dysfunction in patients with tension headache].

    Science.gov (United States)

    Chutko, L S; Surushkina, S Iu; Rozhkova, A V; Iakovenko, E A; Bykova, Iu L; Nikishina, I S

    2013-01-01

    The article is devoted to the study of cognitive dysfunction in patients suffering from tension headaches. Patients had attention and memory dysfunction, higher levels of anxiety, asthenia and subclinical symptoms of depression. The high efficacy of cerebrolysin in the restoration of cognitive dysfunction confirmed by the data of clinical, psychological and neuropsychological studies was shown. PMID:23739500

  1. Collapse of Corroded Pipelines under Combined Tension and External Pressure.

    Directory of Open Access Journals (Sweden)

    Hao Ye

    Full Text Available In this work, collapse of corroded pipeline under combined external pressure and tension is investigated through numerical method. Axially uniform corrosion with symmetric imperfections is firstly considered. After verifying with existing experimental results, the finite element model is used to study the effect of tension on collapse pressure. An extensive parametric study is carried out using Python script and FORTRAN subroutine to investigate the influence of geometric parameters on the collapse behavior under combined loads. The results are used to develop an empirical equation for estimating the collapse pressure under tension. In addition, the effects of loading path, initial imperfection length, yielding anisotropy and corrosion defect length on the collapse behavior are also investigated. It is found that tension has a significant influence on collapse pressure of corroded pipelines. Loading path and anisotropic yielding are also important factors affecting the collapse behavior. For pipelines with relatively long corrosion defect, axially uniform corrosion models could be used to estimate the collapse pressure.

  2. Tension-induced vesicle fusion: pathways and pore dynamics

    DEFF Research Database (Denmark)

    Shillcock, Julian C.

    2008-01-01

    fusion time on membrane tension implies that the fusion process is completed by overcoming two energy barriers with scales of 13kBT and 11kBT. The fusion pore radius as a function of time has also been extracted from the simulations, and provides a quantitative measure of the fusion dynamics which...

  3. Aerodynamic Profiles of Women with Muscle Tension Dysphonia/Aphonia

    Science.gov (United States)

    Gillespie, Amanda I.; Gartner-Schmidt, Jackie; Rubinstein, Elaine N.; Abbott, Katherine Verdolini

    2013-01-01

    Purpose: In this study, the authors aimed to (a) determine whether phonatory airflows and estimated subglottal pressures (est-P[subscript sub]) for women with primary muscle tension dysphonia/aphonia (MTD/A) differ from those for healthy speakers; (b) identify different aerodynamic profile patterns within the MTD/A subject group; and (c) determine…

  4. Instructional Design and Professional Informal Learning: Practices, Tensions, and Ironies

    Science.gov (United States)

    Yanchar, Stephen C.; Hawkley, Melissa N.

    2015-01-01

    This qualitative study explored the nature of informal learning in professional instructional designers' everyday work activities. Based on intensive interviews with six full-time practitioners, and using a hermeneutic form of data analysis, this study produced seven themes concerning the practices, tensions, and ironies associated with this…

  5. Contracting for Independent Evaluation: Approaches to an Inherent Tension

    Science.gov (United States)

    Klerman, Jacob Alex

    2010-01-01

    There has recently been discussion of whether independent contract evaluation is possible. This article acknowledges the inherent tension in contract evaluation and in response suggests a range of constructive approaches to improving the independence of contract evaluation. In particular, a clear separation between the official evaluation report…

  6. Multiscale surface roughening of commercial purity titanium during uniaxial tension

    International Nuclear Information System (INIS)

    The mechanisms of the surface roughening of the titanium specimens during uniaxial tension were demonstrated. By means of optical profilometry and electron backscattered diffraction it was shown that the formation of surface roughening is a multilevel process. The correlation between the density of slip in some grains, and grain rotation, and their displacement towards the free surface was investigated

  7. Tension induced phase transitions in biomimetic fluid membranes

    Science.gov (United States)

    Shapiro, Marc; Vlahovska, Petia

    2012-11-01

    Membranes in eukaryotic cells are mixtures of hundreds of lipid species. The lipid diversity enables membranes to phase separate and form domains, called rafts, which play a critical role in cell functions such as signaling and trafficking. The phase transitions underlying raft formation have been extensively studied as a function of temperature and composition. However, the third dimension of the phase diagram, i.e., the tension (2D pressure), is still unexplored because membrane tension is difficult to control and quantify. To overcome this challenge, we develop two approaches, capillary micromechanics and electrodeformation, in which the tension is regulated by the area dilation accompanying deformation of a vesicle (a closed membrane). The first technique consists of forcing an initially quasi-spherical vesicle through a tapered glass microcapillary, while the second method utilizes uniform electric fields to deform the vesicle into an ellipsoid. Domains are visualized using a fluorescent dye, which preferentially partitions in one of the phases. The experimental results suggest that the miscibility temperature (at which domains form in an initially homogeneous membrane) increases with applied tension. Domain motions and coarsening are also investigated.

  8. Surface energy and surface tension of liquid metal nanodrops

    OpenAIRE

    Shebzukhov A.A.; Shebzukhova M.A.

    2011-01-01

    A unitary approach has been proposed for the calculation of surface energy and surface tension of nanoparticle being in equilibrium with its saturated vapor on both flat and curved surfaces at given temperature. The final equations involve parameters dependent on the type of premelting structure: bcc, fcc or hcp.

  9. Drops, Sieves, and Paintbrushes: Teaching About Surface Tension

    Science.gov (United States)

    Barnes, George B.

    1978-01-01

    Surface tension, a characteristic of liquids, is discussed in this article. Several activities appropriate to the elementary grades are described and explained. Each activity uses common materials to explore this tendancy of water to act as if it were surrounded by a membrane. (MA)

  10. A Modified Jaeger's Method for Measuring Surface Tension.

    Science.gov (United States)

    Ntibi, J. Effiom-Edem

    1991-01-01

    A static method of measuring the surface tension of a liquid is presented. Jaeger's method is modified by replacing the pressure source with a variable pressure head. By using this method, stationary air bubbles are obtained thus resulting in controllable external parameters. (Author/KR)

  11. A density gradient theory based method for surface tension calculations

    DEFF Research Database (Denmark)

    Liang, Xiaodong; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2016-01-01

    The density gradient theory has been becoming a widely used framework for calculating surface tension, within which the same equation of state is used for the interface and bulk phases, because it is a theoretically sound, consistent and computationally affordable approach. Based on the observati...

  12. Dropwise Condensation of Low Surface Tension Fluids on Omniphobic Surfaces

    Science.gov (United States)

    Rykaczewski, Konrad; Paxson, Adam T.; Staymates, Matthew; Walker, Marlon L.; Sun, Xiaoda; Anand, Sushant; Srinivasan, Siddarth; McKinley, Gareth H.; Chinn, Jeff; Scott, John Henry J.; Varanasi, Kripa K.

    2014-03-01

    Compared to the significant body of work devoted to surface engineering for promoting dropwise condensation heat transfer of steam, much less attention has been dedicated to fluids with lower interfacial tension. A vast array of low-surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants are used in a number of industrial applications, and the development of passive means for increasing their condensation heat transfer coefficients has potential for significant efficiency enhancements. Here we investigate condensation behavior of a variety of liquids with surface tensions in the range of 12 to 28 mN/m on three types of omniphobic surfaces: smooth oleophobic, re-entrant superomniphobic, and lubricant-impregnated surfaces. We demonstrate that although smooth oleophobic and lubricant-impregnated surfaces can promote dropwise condensation of the majority of these fluids, re-entrant omniphobic surfaces became flooded and reverted to filmwise condensation. We also demonstrate that on the lubricant-impregnated surfaces, the choice of lubricant and underlying surface texture play a crucial role in stabilizing the lubricant and reducing pinning of the condensate. With properly engineered surfaces to promote dropwise condensation of low-surface tension fluids, we demonstrate a four to eight-fold improvement in the heat transfer coefficient.

  13. Tension pneumothorax during flexible bronchoscopy in a nonintubated infant.

    Science.gov (United States)

    Chan, Ian A; Gamble, Jonathan J

    2016-04-01

    We describe the case of a tension pneumothorax occurring during flexible bronchoscopy in a nonintubated infant. The pneumothorax likely occurred secondary to wall source oxygen insufflation via the bronchoscope without sufficient gas egress. The use of wall source oxygen via the bronchoscope working channel is inherently dangerous and should be avoided. PMID:26740408

  14. Surface tension driven shaping of adhesive microfluidic channel walls

    DEFF Research Database (Denmark)

    Janting, Jakob; Storm, Elisabeth K.; Geschke, Oliver

    2005-01-01

    The feasibility of making microfluidic channels with different wall geometries using adjacent lines of dispensed adhesive between substrates has been studied. Important parameters for the geometry have been identified to be: surface tension (adhesive / substrates), adhesive viscosity / thixotropy....... The studied adhesives are DYMAX 9-20318-F, 3070, 9001 version 3.5, and Sylgard 184 PDMS....

  15. Multiscale surface roughening of commercial purity titanium during uniaxial tension

    Energy Technology Data Exchange (ETDEWEB)

    Panin, Alexey, E-mail: pav@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Kazachenok, Marina, E-mail: kms@ispms.tsc.ru; Kozelskaya, Anna, E-mail: annakozelskaya@gmail.com; Sinyakova, Elena, E-mail: mea@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Lider, Andrey, E-mail: lider@tpu.ru; Sklyarova, Elena, E-mail: skea@tpu.ru [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    The mechanisms of the surface roughening of the titanium specimens during uniaxial tension were demonstrated. By means of optical profilometry and electron backscattered diffraction it was shown that the formation of surface roughening is a multilevel process. The correlation between the density of slip in some grains, and grain rotation, and their displacement towards the free surface was investigated.

  16. Failed needle decompression of bilateral spontaneous tension pneumothorax.

    Science.gov (United States)

    Bach, P T; Sølling, C

    2015-07-01

    This case report presents a young male admitted with primary bilateral spontaneous tension pneumothorax and severe respiratory distress. This is an extremely rare condition. The patient was on the verge of hypoxic cardiac arrest and the attempted needle thoracocentesis was unsuccessful. Needle thoracocentesis in the midclavicular line of the second intercostal space is widely used and recommended as first-line treatment of tension pneumothorax. Reviewing the literature, the procedure is not based on solid evidence. It has high failure rates and potentially serious complications. Alternatives to this approach are perhaps more appropriate. Correctly done, needle thoracocentesis has its place in the presence of a diagnosed or suspected tension pneumothorax when no other options are available. If needle thoracocentesis is chosen, then insertion in the mid-anterior axillary line of the 3rd-5th intercostal space is an appropriate alternative site. Otherwise, lateral thoracostomy, with or without chest tube insertion, is a safe procedure with a high success rate. It should be considered as the first-line treatment of tension pneumothorax, particularly in the unstable patient.

  17. A numerical investigation of the continuous bending under tension test

    NARCIS (Netherlands)

    Hadoush, A.; Boogaard, van den A.H.; Emmens, W.C.

    2011-01-01

    In this paper the continuous bending under tension test is analyzed by numerical simulation. The ability of achieving high strains by combined stretching and bending is considered. This deformation mode has similarities with the deformation that takes place in incremental sheet forming (ISF) and may

  18. Interfacial tension measurements using MRI drop shape analysis.

    Science.gov (United States)

    Hussain, R; Vogt, S J; Honari, A; Hollingsworth, K G; Sederman, A J; Mitchell, J; Johns, M L

    2014-02-18

    Accurate interfacial tension data for fluid systems such as hydrocarbons and water is essential to many applications such as reservoir oil and gas recovery predictions. Conventional interfacial tension measurement techniques typically use optical images to analyze droplet shapes but require that the continuous-phase fluid be optically transparent and that the fluids are not refractive index matched. Magnetic resonance images obtain contrast between fluids using other mechanisms such as magnetic relaxation weighting, so systems that are impossible to measure with optical methods may be analyzed. In this article, we present high-field (9.4 T) MRI images of various droplets analyzed with axisymmetric drop shape analysis. The resultant interfacial tension data show good agreement with literature data. The method is subsequently demonstrated using both opaque continuous phases and refractive-index-matched fluids. We conclude with a brief consideration of the potential to extrapolate the methodology to lower magnetic fields (0.3 T), featuring more accessible hardware; although droplet imaging is possible, resolution and stability do not currently permit accurate interfacial tension measurements. PMID:24471906

  19. Skills Recognition and Validation--Complexity and Tensions

    Science.gov (United States)

    Cavaco, Carmen

    2009-01-01

    This article seeks to identify and examine the reasons for the complexity and tensions underlying the skills recognition, accreditation and certification scheme (SRAC) that has been in place in Portugal since 2001. Empirical data were collected through semi-directive interviews with staff in three Centros Novas Oportunidades [CNOs] [New…

  20. Determination of membrane tension during balloon distension of intestine.

    Science.gov (United States)

    Gregersen, H; Kassab, G S; Fung, Y C

    2004-09-01

    During the last decades, it has become increasingly common to make balloons distension in visceral organs in vivo. In particular this is true for studies of gastrointestinal motor function and biomechanics. Balloon distension is often used for assessment of small intestinal compliance and tension based on Laplace's law for cylindrical pressure pipes. This commonly used law is valid only when the balloon-distended intestine is cylindrical. Experimentally, it is seen that the diameter of the balloon-distended intestine is not a constant, but variable in the axial direction. Hence, it is necessary to improve Laplace's law for intestinal investigation. In this paper we develop the framework for determination of the tension distribution in circumferential and longitudinal direction during balloon distension. When the radii of curvature are measured from a photograph of the intestinal profile, then the membrane stress resultants can be computed everywhere in the intestine in contact with the balloon from the equations of equilibrium. The experimental data were obtained from small intestinal segments from five pigs and three guinea pigs. Papaverine was injected before the animals were sacrificed to relax the intestinal smooth muscle. The segments were immersed in a bath with calcium-free Krebs solution with dextran and EGTA. A balloon was distended in the lumen with pressures up to 15 cmH2O in the pigs and 10 cmH2O in the guinea pigs and radii were measured along the z-axis. The tension in circumferential direction had its maximum approximately 25% away from the middle of the balloon. The circumferential tension was 2-3 times higher than the longitudinal tension. In conclusion when we know the shape of the intestine, we can compute the circumferential and longitudinal components of tension. The large variation in tensions along the z axis must be considered when performing balloon distension studies in the gastrointestinal tract for studying physiological and

  1. Tensiones de una triple vocación urbana: San Bernardo en su proceso de absorción por Santiago de Chile / Tensions of a triple urban vocation: San Bernardo and its absorption process from Santiago de Chile

    OpenAIRE

    Daniela Boccardo Apablaza

    2012-01-01

    ResumenEl fenómeno expansivo de una metrópoli muchas veces va incorporando a su tejido urbano centralidades preexistentes. Entender los efectos de la absorción metropolitana sobre la centralidad menor, es el objetivo de esta investigación sobre San Bernardo y Santiago de Chile. San Bernardo en su proceso de absorción se ha visto enfrentado a nuevas demandas, que lo tensionan a desempeñarse como periferia o subcentro de Santiago, mientras debe seguir respondiendo como centro y capital de una p...

  2. Rheological Parameters as Affected by Water Tension in Subtropical Soils

    Directory of Open Access Journals (Sweden)

    Patricia Pértile

    2016-01-01

    Full Text Available ABSTRACT Rheological parameters have been used to study the interaction between particles and the structural strength of soils subjected to mechanical stresses, in which soil composition and water content most strongly affect soil resistance to deformation. Our objective was to evaluate the effect of water tension on rheological parameters of soils with different mineralogical, physical, and chemical composition. Surface and subsurface horizons of four Oxisols, two Ultisols, one Alfisol, and one Vertisol were physically and chemically characterized; their rheological parameters were obtained from amplitude sweep tests under oscillatory shear on disturbed soil samples that were saturated and subjected to water tension of 1, 3, 6, and 10 kPa. In these samples, the rheological parameters linear viscoelastic deformation limit (γL, maximum shear stress (τmax, and integral z were determined. By simple regression analysis of the rheological parameters as a function of soil water tension, we observed increased mechanical strength with increasing water tension up to at least 6 kPa, primarily due to increased capillary forces in the soil. However, increased elasticity assessed by γL was not as expressive as the increase in structural rigidity assessed by τmax and integral z. Elastic deformation of the soil (γL increases with the increase in the number of bonds among particles, which depend on the clay, total carbon, expansive clay mineral, and cation contents; however, maximum shear resistance (τmax and structural stiffness (integral z mainly increase with clay, kaolinite, and oxide content by increasing the strength of interparticle bonds. A decrease in mechanical strength occurs for water tension of 10 kPa (the lowest water content evaluated in sandy horizons or in horizons with a high proportion of resistant microaggregates (pseudosand, when associated with low bulk density, due to fewer points of contact between soil particles and therefore

  3. Survismeter, 3-in-1 Instrument for simultaneous measurements of surface tension, inter facial tension (IFT) and viscosity

    International Nuclear Information System (INIS)

    The article presents Inter Facial Tension (1FT) (lemda ift, N m/sub -1/) of benzene-water; surface tensions Limda, N m/sub -1/) and viscosities (neta, N s m/sub -2/) of ethanol, glycerol, ethyl acetate, n-hexane, diethyl ether, chloroform, benzene, carbon tetrachloride (CCI/sub 4/), formic acid, measured with Survismeter with +- 1.1x10/sub -5/ N m/sub -5/, N m/sub -1/, +-1.3x10/sub -5/ N mol and +-1.1x10/sub -6/N s m/sub -2/ accuracies respectively. Also the surface tension and viscosities of carboxymethylcellulose (CMC), dodecyfbenzenesulfonicacid (DB SA) and tetramethylammoniumhydroxide (TMAH) in aqueous media have been measured with survismeter at 298.15 K. IFT of water and benzene interface was determined with survlsmeter. The survismeter saves respurces, user's efforts and infrastructure more than 80% as compared to usual methods and prevents 80% disposal of materials to environment. It very accurately measures surface tension and IFT of volatile and poisonous liquids at any desired temperatures as liquids are jacked (jacketed) in closed glass made bulbs. (author)

  4. Survismeter, 3-in-1 Instrument for Simultaneous Measurements of Surface Tension, Inter Facial Tension (IFT and Viscosity

    Directory of Open Access Journals (Sweden)

    Man Singh

    2007-12-01

    Full Text Available The article presents Inter Facial Tension (IFT (ift, N m-1 of benzene-water; surface tensions (, N m-1 and viscosities (, N s m-2 of ethanol, glycerol, ethyl acetate, n-hexane, diethyl ether, chloroform, benzene, carbon tetrachloride [CCl4], formic acid, measured with Survismeter with ± 1.1x10-5 N m-1, ± 1.3x10-5 N m-1 and ± 1.1x10-6 N s m-2 accuracies respectively. Also the surface tension and viscosities of carboxymethylcellulose (CMC, dodecylbenzenesulfonicacid (DBSA and tetramethylammoniumhydroxide (TMAH in aqueous media have been measured with survismeter at 298.15 K. IFT of water and benzene interface was determined with survismeter. The survismeter saves resources, user’s efforts and infrastructure more than 80 % as compared to usual methods and prevents 80% disposal of materials to environment. It very accurately measures surface tension and IFT of volatile and poisonous liquids at any desired temperatures as liquids are jacked (jacketed in closed glass made bulbs.

  5. Conceptos del maquinado con altas velocidades de corte aplicado en moldes y matrices.

    Directory of Open Access Journals (Sweden)

    F. Martínez Aneiro

    2007-01-01

    Full Text Available La demanda de componentes mecánicos de alta calidad y gran exactitud para sistemas de elevada precisión esta aumentando considerablemente en los últimos años a nivel mundial. Este hecho ha provocado el desarrollo de nuevas tecnologías aplicadas a los procesos de corte.El desarrollo integral de las máquinas herramientas (controles, husillos de alta velocidad de las herramientas de corte (nuevos materiales para los substratos y capas y de la tecnología de maquinado posibilitó la aplicación del corte a altas velocidades (High speed Cutting HSC. El aumento de las velocidades de corte es una de las formas de incrementar la eficiencia de los procesos productivos a través de la reducción de los tiempos de fabricación. La disminución en varias veces de los tiempos de fabricación, se logra no solo por los tiempos de maquinado sino también por la sustitución o reducción de otros procesos de elaboración que forman parte de la cadena productiva, que en ocasiones son relativamente lentos como son la electroerosión, el acabado manual en la producción de moldes y troqueles así como los cambios de operaciones de la pieza bruta. Por ser un proceso relativamente nuevo, apenas desde los años 90 es que se implementa la introducción del HSC y muchas cuestiones tecnológicas aun están sin respuesta. Por otro lado las características ya conocidas de esta nueva tecnología indican una buena perspectiva de aplicación en los más diversos segmentos de la industria.The demand of mechanical components of high quality and great accuracy for systems of high precision, increasing considerably in the last years at world level. This fact has caused the development of new applied technologies to the cutting processes. The integral development of machine tools (you control, high-speed spindle of the cutting tools (new materials for the substrata and layers and of the technology of having schemed facilitated the application of the cut with high speeds

  6. Data-based hybrid tension estimation and fault diagnosis of cold rolling continuous annealing processes.

    Science.gov (United States)

    Liu, Qiang; Chai, Tianyou; Wang, Hong; Qin, Si-Zhao Joe

    2011-12-01

    The continuous annealing process line (CAPL) of cold rolling is an important unit to improve the mechanical properties of steel strips in steel making. In continuous annealing processes, strip tension is an important factor, which indicates whether the line operates steadily. Abnormal tension profile distribution along the production line can lead to strip break and roll slippage. Therefore, it is essential to estimate the whole tension profile in order to prevent the occurrence of faults. However, in real annealing processes, only a limited number of strip tension sensors are installed along the machine direction. Since the effects of strip temperature, gas flow, bearing friction, strip inertia, and roll eccentricity can lead to nonlinear tension dynamics, it is difficult to apply the first-principles induced model to estimate the tension profile distribution. In this paper, a novel data-based hybrid tension estimation and fault diagnosis method is proposed to estimate the unmeasured tension between two neighboring rolls. The main model is established by an observer-based method using a limited number of measured tensions, speeds, and currents of each roll, where the tension error compensation model is designed by applying neural networks principal component regression. The corresponding tension fault diagnosis method is designed using the estimated tensions. Finally, the proposed tension estimation and fault diagnosis method was applied to a real CAPL in a steel-making company, demonstrating the effectiveness of the proposed method.

  7. Behavior of high efficiency electric motors; Comportamiento de motores electricos de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Bonett, Austin H. [IEEE, (United States)

    2001-09-01

    The energy efficiency is one of the main parameters in the design of the industrial motors of general purpose; nevertheless, it is avoided that it is at the cost of the reliability or to the global performance of the motor. Exist user groups of this equipment that consider that, in the search of a greater efficiency, the useful life period is diminished and the characteristics of operation of the motor are affected. During the past last years, the author has studied the aspects of quality and reliability, as well as the operative advantages of the high efficiency motors and written down the increasing interest for these aspects. Also he has detected that a great number of users has realized that, additionally to the obvious energy saving, the efficient motor offers a greater reliability and a longer useful life in most of the industrial applications. The objective of this article is to present the differences in the quality levels, reliability and operation parameters of high efficiency squirrel cage type electrical motors with those of the motors of standard manufacture. [Spanish] La eficiencia energetica es uno de los principales parametros en el diseno de los motores industriales de proposito general; sin embargo, se evita que sea a costa de la confiabilidad o del desempeno global del motor. Existen grupos de usuarios de estos equipos que consideran que, en la busqueda de una mayor eficiencia, se disminuye el periodo de vida util y se afectan las caracteristicas de operacion del motor. Durante los ultimos anos, el autor ha estudiado los aspectos de calidad y confiabilidad, asi como las ventajas operativas de los motores de alta eficiencia y anotado el incremento del interes por estos aspectos. Tambien ha detectado que un gran numero de usuarios se ha dado cuenta que, adicionalmente a los obvios ahorros de energia, el motor eficiente ofrece una mayor confiabilidad y una vida util mas larga en la mayoria de las aplicaciones industriales. El objetivo de este

  8. Altas Habilidades/Superdotação e a psicopedagogia modular: avaliando potencialidades

    Directory of Open Access Journals (Sweden)

    Elizabeth Carvalho da Veiga

    2014-09-01

    Full Text Available http://dx.doi.org/10.5902/1984686X14283A psicopedagogia modular é uma proposta que apresenta um modelo de avaliação  dinâmica, um processo interativo, flexível e individualizado, buscando compreender a funcionalidade dos sistemas inteligentes. A presente investigação foi realizada com crianças que buscaram avaliação psicopedagógica no Núcleo de Pratica em Psicologia da PUCPR  e teve por objetivos apontar a funcionalidade dos sistemas inteligentes, reconhecendo a existência ou não , de altas habilidades e identificar a predominância  entre os sistemas analítico , prático ou criativo , utilizados pela clientela  em questão. A metodologia de avaliação  contou com os seguintes instrumentos : entrevista evolutiva modular; questionário para os pais; brasão familiar; E.M.C.A ; WISC III;  provas multimodais e provas cognitivas modulares. Este processo levou aproximadamente 25 encontros de  cinquenta minutos .Participaram da pesquisa 28 alunos de 8 a 17 anos  de diferentes escolas de Curitiba-Pr/ Brasil. Por meio dos dados obtidos, ainda que apurados a partir de uma amostra pequena, pode-se concluir que a proposta da Psicopedagogia Modular  com seu  modelo dinâmico de avaliação, favoreceu a identificação das altas habilidades/superdotação, na sua especificidade, ou seja ,  considerando  a multiplicidade dos sistemas inteligentes  e as habilidades envolvidas nos processos mentais que sustentam  as inteligências analítica, prática e criativa. A visão modular no processo de identificação traz uma identidade ao superdotado, tirando-o  da concepção generalista.

  9. Por que Melipona scutellaris (Hymenoptera, Apidae forrageia sob alta umidade relativa do ar?

    Directory of Open Access Journals (Sweden)

    Marília D. e Silva

    2011-06-01

    Full Text Available Há evidências de que a temperatura do ar e a umidade relativa afetam a atividade de voo de espécies de abelhas sociais Meliponini. Em particular, as espécies grandes do gênero Melipona Illiger, 1806 responderiam de maneira mais estreita à variação na umidade relativa. Neste estudo defende-se o argumento de que a umidade relativa seja uma variável de confusão. Nesta linha de argumentação, também foi analisado o papel da coleta de pólen sobre o ritmo diário de forrageio. A robusta Melipona scutellaris (Latreille, 1811 foi usada como modelo e a atividade diária de voo e de forrageio de pólen foi medida em 12 colônias (4 colônias/hábitat, em três tipos de hábitats, que variam principalmente quanto à pluviosidade, na área de distribuição natural desta espécie (Floresta Pluvial, Floresta Sazonal e Transição Floresta Tropical-Cerrados. A maioria da atividade de voo acontece durante a manhã. A atividade de forrageio das colônias foi mais elevada nas primeiras horas do alvorecer, quando a umidade relativa também era alta, frequentemente associada a picos de coleta de pólen. A atividade de voo decresceu abruptamente durante as temperaturas altas ao redor do meio dia. A relação da atividade de voo com a umidade relativa foi altamente significativa e linear, contrastando com a relação significativa e unimodal com a temperatura. Na relação com o forrageio de M. scutellaris, a umidade relativa se configura como uma variável contingente, em hábitats tropicais úmidos, considerando os padrões diários de variação do microclima e de forrageio de pólen. Este último padrão também sustenta a hipótese de partição temporal de fontes florais de pólen.

  10. Neurociências, altas habilidades e implicações no currículo

    Directory of Open Access Journals (Sweden)

    Amauri Betini Bartoszeck

    2014-09-01

    Full Text Available http://dx.doi.org/10.5902/1984686X14284O presente estudo inicialmente define e descreve as sub-disciplinas que compõem as neurociências com potenciais aplicações educacionais para crianças e adultos  identificados com altas habilidades. Objetiva-se com uma breve introdução morfofuncional ao sistema nervoso que serve de pano de fundo para auxiliar o entendimento da ponte teórico-experimental da relação de neurociências e altas habilidades. São salientados aspectos da base evolucionista e biológica, que conjectura-se possam estar estruturados nos circuitos neuronais, subjacentes aos padrões de realce da sensibilidade auditiva e eficiência da memória. Discute-se como se dá a codificação da informação, formas de detectar associações e analogias, exemplificando-se regiões cerebrais envolvidas no pensamento matemático. São analisadas modificações estruturais e a dinâmica da plasticidade sináptica subjacentes à “talentosidade” e como a base genética interage com as experiências do ambiente. São também discutidos métodos usuais na identificação de crianças e adolescentes com indicação de superdotação. Avaliam-se comparativamente características de crianças “prodígios” e “savants”. São listadas perguntas motivadoras e instigantes para o aprofundamento de pesquisas em neurociências que possam consolidar o conhecimento de como áreas do cérebro processam a informação  de modo vantajoso no raciocínio e aprendizagem, com implicações para educadores. Conclui-se com sugestões de métodos alternativos de ensino, enfatizando-se exemplos de aplicações práticas na área de ciências biológicas.

  11. Anterior cruciate ligament graft tensioning. Is the maximal sustained one-handed pull technique reproducible?

    Directory of Open Access Journals (Sweden)

    Hirpara Kieran M

    2011-07-01

    Full Text Available Abstract Background Tensioning of anterior cruciate ligament (ACL reconstruction grafts affects the clinical outcome of the procedure. As yet, no consensus has been reached regarding the optimum initial tension in an ACL graft. Most surgeons rely on the maximal sustained one-handed pull technique for graft tension. We aim to determine if this technique is reproducible from patient to patient. Findings We created a device to simulate ACL reconstruction surgery using Ilizarov components and porcine flexor tendons. Six experienced ACL reconstruction surgeons volunteered to tension porcine grafts using the device to see if they could produce a consistent tension. None of the surgeons involved were able to accurately reproduce graft tension over a series of repeat trials. Conclusions We conclude that the maximal sustained one-handed pull technique of ACL graft tensioning is not reproducible from trial to trial. We also conclude that the initial tension placed on an ACL graft varies from surgeon to surgeon.

  12. Rein tension acceptance in young horses in a voluntary test situation

    DEFF Research Database (Denmark)

    Christensen, Janne Winther; zharkikh, T.L.; Antoine, A.;

    2011-01-01

    ) to obtain a food reward in a voluntary test situation. On each test day, each horse was exposed to 2 control sessions (loose reins), an intermediate and a short rein session (1 min/session). Rein tension, heart rate and behaviour were recorded. Results: The horses applied significantly more tension...... on the first day (mean rein tension: 10.2 N), compared to the second and third test day (Day 2: 6.0 and Day 3: 5.7 N). The horses showed significantly more conflict behaviour in the short rein treatment. There was no treatment effect on heart rate. Conclusions and potential relevance: The horses applied...... the highest rein tension on the first day, and apparently learned to avoid the tension, rather than habituate to it. Rein tension correlated with expression of conflict behaviour, indicating that the horses found the tension aversive. Further studies should focus on the correlation between rein tension...

  13. Anterior cruciate ligament graft tensioning. Is the maximal sustained one-handed pull technique reproducible?

    LENUS (Irish Health Repository)

    O'Neill, Barry J

    2011-07-20

    Abstract Background Tensioning of anterior cruciate ligament (ACL) reconstruction grafts affects the clinical outcome of the procedure. As yet, no consensus has been reached regarding the optimum initial tension in an ACL graft. Most surgeons rely on the maximal sustained one-handed pull technique for graft tension. We aim to determine if this technique is reproducible from patient to patient. Findings We created a device to simulate ACL reconstruction surgery using Ilizarov components and porcine flexor tendons. Six experienced ACL reconstruction surgeons volunteered to tension porcine grafts using the device to see if they could produce a consistent tension. None of the surgeons involved were able to accurately reproduce graft tension over a series of repeat trials. Conclusions We conclude that the maximal sustained one-handed pull technique of ACL graft tensioning is not reproducible from trial to trial. We also conclude that the initial tension placed on an ACL graft varies from surgeon to surgeon.

  14. Post-tensioned concrete floor slab design of a shopping centre

    Institute of Scientific and Technical Information of China (English)

    刘洋; 于霞

    2011-01-01

    Post-tensioned Concrete slab can provide large clear span, and also has better performance in crack control and deflection. The topic below introduced the design process of the post-tensioned floor slab of a shopping centre.

  15. Twin stability in highly nanotwinned Cu under compression, torsion and tension

    DEFF Research Database (Denmark)

    Hodge, A.M.; Furnish, T.A.; Shute, C.J.;

    2012-01-01

    Twin stability under four distinct mechanical loading states has been investigated for highly nanotwinned Cu containing parallel nanotwins 40 nm thick. Observed deformation-induced microstructural changes under tension, compression, tension–tension fatigue and torsion are qualitatively compared...

  16. CONDITION MONITORING AND FAULT DIAGNOSIS FOR TENSION UNBALANCE OF ROPES IN MULTI-ROPE FRICTION WINDER

    Institute of Scientific and Technical Information of China (English)

    杨兆建; 王勤贤; 任芳

    1997-01-01

    This paper analyzes the reasons of the tension unbalance of the ropes in multi-rope friction winder, introduces the method of an on-line monitoring rope tensions with a testing device developed by authors, and proposes the criteria of the fault diagnosis and the method of adjustment for the tension unbalance of the ropes, which is important to the theoretical study on the tension unbalance of the ropes and the maintenance of multi-rope winder.

  17. Influence of liquid surface tension (surfactants) on bubble formation at rigid and flexible orifices

    OpenAIRE

    Loubiere, Karine; Hebrard, Gilles

    2004-01-01

    The influence of liquid surface tension on the bubble formation from both rigid and flexible orifice has been investigated. The liquid phases under test are aqueous solutions with butanol or surfactants (cationic, non-ionic and anionic); static and dynamic measurements of liquid surface tension have been performed to characterise them. This study shows that the effect of surface tension on the bubbles generated cannot be analysed only in terms of the static surface tension, but...

  18. Three-Dimensional Smoothed Particle Hydrodynamics Simulation for Liquid Droplet with Surface Tension

    OpenAIRE

    Terissa, Hanifa; Barecasco, Agra; Naa, Christian Fredy

    2013-01-01

    We provide a basic method of Smoothed Particle Hydrodynamics (SPH) to simulate liquid droplet with surface tension in three dimensions. Liquid droplet is a simple case for surface tension modeling. Surface tension works only on fluid surface. In SPH method, we simply apply the surface tension on the boundary particles of liquid. The particle on the 3D boundary was detected dynamically using Free-Surface Detection algorithm. The normal vector and curvature of the boundary surface were calculat...

  19. Thermodynamic Modeling of Surface Tension of Aqueous Electrolyte Solution by Competitive Adsorption Model

    OpenAIRE

    Mohamad Javad Kamali; Zakarya Kamali; Gholamhossein Vatankhah

    2015-01-01

    Thermodynamic modeling of surface tension of different electrolyte systems in presence of gas phase is studied. Using the solid-liquid equilibrium, Langmuir gas-solid adsorption, and ENRTL activity coefficient model, the surface tension of electrolyte solutions is calculated. The new model has two adjustable parameters which could be determined by fitting the experimental surface tension of binary aqueous electrolyte solution in single temperature. Then the values of surface tension for other...

  20. Surface tension examination of various liquid oral, nasal, and ophthalmic dosage forms

    OpenAIRE

    Han, Kimberly; Woghiren, Osakpolor E.; Priefer, Ronny

    2016-01-01

    Surface tension at the surface-to-air interface is a physico-chemical property of liquid pharmaceutical formulations that are often overlooked. To determine if a trend between surface tension and route of administration exists, a suite of oral, nasal, and ophthalmic drug formulations were analyzed. The surface tension at the surface-to-air interface of the oral formulations studied were in or above the range of the surface tension of gastric, duodenum, and jejunum fluids. The range of surface...

  1. Variations of the perception of mood and tension of music excerpts depending on the visual context

    OpenAIRE

    Payri, Blas

    2009-01-01

    We study the influence that image features may have on music tension and liveliness perception. 72 music excerpts from different genres and periods were selected, and 72 still shots were taken from different animation features little known to the subjects. 62 subjects rated the isolated images for tension and liveliness, 37 subjects rated the isolated music excerpts for tension and liveliness, and 153 subjects rated the music excerpts combined with the images for music tension and liveliness,...

  2. Flexor Digitorum Profundus Tendon Tension during Finger Manipulation: A Study in Human Cadaver Hands

    OpenAIRE

    Tanaka, Tatsuro; Amadio, Peter C.; Zhao, Chunfeng; Zobitz, Mark E.; An, Kai-Nan

    2005-01-01

    The purpose of this study was to measure the tension in the flexor digitorum profundus (FDP) tendon in zone II and the digit angle during joint manipulations that replicate rehabilitation protocols. Eight FDP tendons from eight human cadavers were used in this study. The dynamic tension in zone II of the tendon and metacarpophalangeal (MCP) joint angle were measured in various wrist and digit positions. Tension in the FDP tendon increased with MCP joint extension. There was no tension with th...

  3. Small mammals from the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala

    Science.gov (United States)

    Matson, Jason O.; Ordóñez-Garza, Nicté; Woodman, Neal; Bulmer, Walter; Eckerlin, Ralph P.; Hanson, J. Delton

    2014-01-01

    We surveyed the small mammals of remnant mixed hardwood-coniferous cloud forest at elevations ranging from 2,100–2,300 m in the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala. Removal-trapping using a combination of live traps, snap traps, and pitfall traps for 6 days in January 2007 resulted in 175 captures of 15 species of marsupials, shrews, and rodents. This diversity of small mammals is the highest that we have recorded from a single locality of the 10 visited during eight field seasons in the highlands of Guatemala. Based on captures, the most abundant species in the community of small mammals is Peromyscus grandis (n = 50), followed by Handleyomys rhabdops (n = 27), Heteromys desmarestianus(n = 18), Reithrodontomys mexicanus (n = 17), Handleyomys saturatior (n = 16), Sorex veraepacis (n = 15), and Scotinomys teguina (n = 13). The remaining eight species were represented by one to five individuals.

  4. Una Mirada Probabilística al Concreto de Alta Resistencia

    Directory of Open Access Journals (Sweden)

    Zaira A. Cerón S.

    2015-07-01

    Full Text Available Este artículo presenta el análisis probabilístico realizado a dos diseños de mezcla para concreto de alta resistencia como primer paso para obtener un modelo estadístico que logre expresar los resultados de una forma más útil y permita determinar la resistencia y la calidad potencial del concreto. El análisis de resultados del ensayo de resistencia a compresión del concreto se llevó a cabo mediante el uso de un software estadístico llamado SPSS, que a partir de las diferentes variables estadísticas permitió indagar si la distribución de frecuencias, correspondía a la distribución normal que sigue el concreto convencional. Los resultados obtenidos muestran la distribución o la tendencia de resistencia de cada uno de los diseños. El análisis cuantitativo evidencia que la variación de resistencia del concreto refleja con rigor la importancia que tiene conocer las propiedades de la mezcla de concreto y el proceso en los métodos de ensayo.

  5. Neurodesarrollo en egresados de la terapia intensiva neonatal a los 6 meses del alta hospitalaria

    Directory of Open Access Journals (Sweden)

    Dayami Armas-Guerra

    2012-01-01

    Full Text Available Se abordó estudio descriptivo longitudinal de 16 recién nacidos egresados del servicio de Neonatología del Hospital Pediátrico de Holguín, desde febrero a junio del 2009. Se les evaluó desde el punto de vista neurológico a los seis meses del alta hospitalaria. Un 25% presentaron anormalidad del examen neurológico. Las alteraciones leves y moderadas se comportaron igual. El sexo femenino fue el más afectado, la menor edad gestacional y el peso menor de 1500 gramos predispusieron a la aparición de secuelas. La ventilación mecánica, la encefalopatía hipóxico isquémica, intervenciones quirúrgicas complejas, el daño cerebral detectado por ultrasonografía transfontanelar, la edad gestacional por debajo de 34 semanas y la hipoglicemia están vinculados a la anormalidad neurológica de forma significativa.

  6. El sistema penitenciario y carcelario en Colombia: El concepto de alta seguridad en la justicia especializada

    Directory of Open Access Journals (Sweden)

    María Stella Baracaldo Méndez

    2014-03-01

    Full Text Available Colombia heredó de las guerras civiles del siglo XIX una cultura de conflicto político, que tras un descanso, reapareció en la década de los cuarenta con la confrontación de los partidos tradicionales (liberal y conservador y desde los años cincuenta con la aparición gradual de grupos de guerrilla, autodefensas, narcotraficantes, delincuencia común y organizada, entre otros, dando paso a un nuevo y complejo conflicto. Desde 1978 ha predominado la medida del Estado de Conmoción Interior para manejar la seguridad interna sin el reconocimiento del conflicto armado. La reforma constitucional de 1991 introdujo un nuevo sistema de justicia que, por mes, genera un promedio de 1500 reclusos, cantidad que actualmente desbordan la capacidad de las cárceles, administradas bajo el sistema progresivo de mínima, media y alta seguridad. Hoy, con la declaración del conflicto por el presidente Santos y una justicia transicional para el proceso de paz, está en curso la reforma del Código Penitenciario y Carcelario y fue decretada la emergencia carcelaria ante un nivel de hacinamiento del 52% y graves violaciones de derechos humanos de la población reclusa.DOI: http://dx.doi.org/10.5377/rpsp.v3i1.1330

  7. Roma-Napoli ad Alta Velocità. Occasione per un riequilibrio modale

    Directory of Open Access Journals (Sweden)

    Daniela Cerrone

    2008-06-01

    Full Text Available Sulle tratte nazionali, sempre più evidenti risultano i limiti del trasporto aereo sul quale, in modo determinante, incidono i tempi per raggiungere gli aeroporti, per le operazioni di chek-in e di imbarco. D’altra parte, sembra oramai esaurita la capacità del territorio di sostenere, soprattutto in prossimità delle grandi città e lungo le direttrici principali, ancora un aumento del traffico automobilistico. In tale scenario, la messa in esercizio in Italia delle prime tratte ferroviarie ad Alta Velocità prefigurarono un sempre maggiore utilizzo di tali vettori a fronte di una sostanziale diminuzione del ricorso al trasporto aereo e soprattutto privato su gomma. L’articolo propone una comparazione, in termini di costi, tempi di percorrenza, confort di viaggio, delle diverse modalità di trasporto a cui è possibile fare ricorso sulla tratta Roma-Napoli ed è finalizzato ad evidenziare gli elementi che incidono sul riequilibrio modale tra i collegamenti esistenti tra i due sistemi urbani.

  8. Simple technique for evacuation of traumatic subcutaneous haematomas under tension

    Directory of Open Access Journals (Sweden)

    Hatley Edward

    2005-12-01

    Full Text Available Abstract Background Traumatic subcutaneous haematomas are common cases in the accident and emergency department. Occasionally, urgent evacuation is required to prevent skin necrosis. Methods We present a simple and safe technique, based on a principle similar to liposuction to evacuate traumatic subcutaneous haematomas under tension. Instruments readily available in the accident and emergency department are used without the need of general anaesthesia. Results The technique was performed in six cases without complication such as infection or re-collection of the haematoma under tension. We present two typical scenarios where urgent evacuation was indicated and the technique performed. Conclusion The technique is useful as an urgent and safe procedure in the accident and emergency department setting.

  9. Gravitational Tension, Spacetime Pressure and Black Hole Volume

    CERN Document Server

    Armas, Jay; Sanchioni, Marco

    2015-01-01

    We study the first law of black hole thermodynamics in the presence of surrounding gravitational fields and argue that variations of these fields are naturally incorporated in the first law by defining gravitational tension or gravitational binding energy. We demonstrate that this notion can also be applied in Anti-de Sitter spacetime, in which the surrounding gravitational field is sourced by a cosmological fluid, therefore showing that spacetime volume and gravitational tension encode the same physics as spacetime pressure and black hole volume. We furthermore show that it is possible to introduce a definition of spacetime pressure and black hole volume for any spacetime with characteristic length scales which does not necessarily require a cosmological constant sourcing Einstein equations. However, we show that black hole volume is non-universal in the flat spacetime limit, questioning its significance. We illustrate these ideas by studying the resulting black hole volume of Kaluza-Klein black holes and of...

  10. Iatrogenic tension pneumothorax in children: two case reports

    Directory of Open Access Journals (Sweden)

    Mayordomo-Colunga Juan

    2009-06-01

    Full Text Available Abstract Introduction Two cases of iatrogenic tension pneumothorax in children are reported. Case presentations Case 1: A 2-year-old boy with suspected brain death after suffering multiple trauma suddenly developed intense cyanosis, extreme bradycardia and generalized subcutaneous emphysema during apnea testing. He received advanced cardiopulmonary resuscitation and urgent bilateral needle thoracostomy. Case 2: A diagnostic-therapeutic flexible bronchoscopy was conducted on a 17-month-old girl, under sedation-analgesia with midazolam and ketamine. She very suddenly developed bradycardia, generalized cyanosis and cervical, thoracic and abdominal subcutaneous emphysema. Urgent needle decompression of both hemithoraces was performed. Conclusion In techniques where gas is introduced into a child's airway, it is vital to ensure its way out to avoid iatrogenic tension pneumothorax. Moreover, the equipment to perform an urgent needle thoracostomy should be readily available.

  11. Decaying Asymmetric Dark Matter Relaxes the AMS-Fermi Tension

    CERN Document Server

    Feng, Lei

    2013-01-01

    The first result of AMS-02 confirms the positron fraction excess observed by PAMELA, but in the dark matter (DM) interpretation, its softer spectrum brings a tension between AMS-02 and Fermi-LAT, which reported an excess of the electron plus positron flux. In this work we point out that the asymmetric cosmic ray from asymmetric dark matter (ADM) decay relaxes the tension, and find that at the two-body decay level a bosonic ADM around 2.4 TeV and decaying to\\mu^-\\tau^+ can significantly improve the fits. Based on the R-parity-violating supersymmetry with operators LLE^c, we propose a minimal model to realize that ADM scenario: Introducing a pair of singlets (X,\\bar X) and coupling them to the visible sector via LH_uX, we then obtain a leptonic decaying ADM with TeV-scale mass.

  12. Surface pore tension and adsorption characteristics of polluted sediment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Most natural sediment particles have numerous pores and a complex surface texture which facilitates their adsorption of contaminants. Particle surface structure,therefore,is an important instrumental factor in the transport of contaminants,especially in water environments. This paper reports on the results of adsorption-desorption experiments to analyze polluted sediment surface pore tension characteristics performed on samples from the bottom of Guanting Reservoir. In our analysis,the Frenkel-Halsey-Hill(FHH) equation is applied to calculate the fractal dimensions of particles to quantify the surface roughness and pore tension characteristics. The results show that the surface fractal dimensions of sediment particle surfaces normally measure from 2.6 to 2.85. The volume of pores smaller than 10 nm changes significantly after being contaminated with pollutants and the fractal dimension decreases because the pores adsorb the contaminants.

  13. Treating tension-type headache -- an expert opinion

    DEFF Research Database (Denmark)

    Bendtsen, Lars; Jensen, Rigmor

    2011-01-01

    INTRODUCTION: Tension-type headache (TTH) is a highly prevalent disorder with enormous costs for the individual and the society. AREAS COVERED: Nonpharmacological and pharmacological treatments are reviewed. Electromyographic (EMG) biofeedback has a documented effect in TTH, while cognitive-behavioral...... therapy and relaxation training are most likely to be effective. Physical therapy and acupuncture may be valuable options for patients with frequent TTH. Simple analgesics and nonsteroidal anti-inflammatory drugs are recommended for treatment of episodic TTH. Combination analgesics containing caffeine...

  14. Surface tension-like forces determine bacterial shapes: Streptococcus faecium.

    Science.gov (United States)

    Koch, A L; Higgins, M L; Doyle, R J

    1981-03-01

    The same tendency that causes soap bubbles to achieve a minimum surface area for the volume enclosed seems to account for many of the features of growth and division of bacteria, including both bacilli and cocci. It is only necessary to assume that growth takes place in zones and that only in these zones does the tension caused by hydrostatic pressure create the strain that forces the cell to increase the wall area. The stress developed by osmotic pressure creates strains that significantly lower the free energy of bond splitting by hydrolysis or transfer. We believe this is sufficient to make growing wall have some of the properties ordinarily associated with surface tension. The feature common to all bacterial cell wall growth is that peptidoglycan is inserted under strain-free conditions. Only after the covalent links have been formed are the intervening stressed peptide bonds cleaved so that the new unit supports the stress due to hydrostatic pressure. The present paper analyses the growth of Streptococcus faecium in these terms. This is a particularly simple case and detailed data concerning morphology are available. The best fit to the data is achieved by assuming that growth takes place in a narrow region near the splitting septum and that the septal material is already under tension as it is externalized and is twice as thick as the external wall throughout the development of the nascent poles. Constancy of the ratio of hydrostatic pressure to the effective surface tension, P/T, is also consistent with electron microscopic observations. PMID:7320694

  15. Tension-loaded bolted connections in steel structures

    OpenAIRE

    Skavhaug, Elin Stensrud; Østhus, Svanhild Irene

    2015-01-01

    The purpose of this thesis is to study the behaviour of bolted steel connections subjected to tension. Quasi-static conditions have been considered. By performing laboratory tests on single bolts and simple T-stub connections the failure modes of the bolts have been examined. Finite element models are created and validated to represent the behaviour observed in the laboratory. Different grip length configurations have been tested for a single bolt and nut assembly subjected to pure tensio...

  16. Globalization, financial capitalism, and corporate social responsibility: Structural tensions

    OpenAIRE

    David Barbosa Ramírez; Christian Medina López; Myriam Vargas López

    2014-01-01

    Globalization and financial capitalism keep a synergy in a global context whose problems such as environmental degradation, social inequity, economic crises and corruption are intensified. Corporate Social Responsibility emerges as a mechanism that seeks to mitigate some of these problems, although its effectiveness and impact today are challenged. The system which globalization, financial capitalism and social responsibility are a part of, is currently facing a number of structural tensions ...

  17. The coopetition paradox and tension in coopetition at multiple levels

    OpenAIRE

    Raza-Ullah, Tatbeeq; Bengtsson, Maria; Kock, Sören

    2014-01-01

    This article explores the nature of the paradox inherent in coopetition; that is, the simultaneous pursuit of cooperation and competition between firms, and emanating tensions that develop at individual, organizational, and inter-organizational levels. We dissect the anatomy of the coopetition paradox to discover how it materializes by creating an external boundary (i.e., via unifying forces) and internal boundaries (i.e., via divergent forces). After explaining the coopetition paradox, we di...

  18. The influence of surface tension gradients on drop coalescence

    OpenAIRE

    Blanchette, François; Messio, Laura; Bush, John W.M.

    2009-01-01

    We present the results of a combined experimental and numerical investigation of the coalescence of a drop with a liquid reservoir of a miscible but distinct fluid. Particular attention is given to elucidating the influence on the coalescence process of a surface tension difference between drop and reservoir. Drops are gently deposited on the surface of the reservoir, and so coalesce with negligible initial vertical velocity. Depending on the drop size and reservoir composition, partial or to...

  19. Study Of Bubble-Count Measurement Of Surface Tension

    Science.gov (United States)

    Nishioka, Gary M.; Berg, James I.

    1993-01-01

    Report presents study of bubble-count method of measurement of surface or interfacial tension of liquids. In method, gas or liquid pumped at known rate along capillary tube. One end of tube open and immersed in liquid that wets tube. Pumped gas or liquid forms bubbles, detaching themselves from immersed open end of tube, and one measures average period, Pi, for formation and detachment of bubbles.

  20. Impact dynamics of surfactant laden drops: dynamic surface tension effects

    OpenAIRE

    Aytouna, M.; Bartolo, D.; Wegdam, G.; Bonn, D.; Rafaï, S.

    2010-01-01

    We study the impact and subsequent retraction of aqueous surfactant-laden drops upon high-speed impact on hydrophobic surfaces. Without surfactants, a rapid expansion of the drop due to the fluid inertia is followed by a rapid retraction, due to the wetting incompatibility. With surfactants, the retraction can be partly or completely inhibited. We provide quantitative measurements showing that both the expansion and the retraction dynamics depend not only on the equilibrium surface tension (S...

  1. Budded membrane microdomains as regulators for cellular tension

    OpenAIRE

    Sens, Pierre; Turner, Matthew S.

    2005-01-01

    We propose a mechanism for mechanical regulation at the membrane of living cells, based on the exchange of membrane area between the cell membrane and a membrane reservoir. The reservoir is composed of invaginated membrane microdomains which are liable to flatten upon increase of membrane strain, effectively controlling membrane tension. We show that the domain shape transition is first order, allowing for coexistence between flat and invaginated domains. During coexistence, the membrane tens...

  2. Nonlocal Theory to Analyse Nanotube Structures under Tension

    OpenAIRE

    Hamidreza Yazdani Sarvestani; Ali Naghashpour

    2015-01-01

    Because nanocomposites have found augmented use in many industries, the analytical solutions are required to be developed. This paper presents the development of a new analytical method for studying nanotube structures under tension using layer-wise and Eringen theories. Two opposite ends of tubes are subjected to normal forces. Nonlocal governing differential equations are derived and presented. The theoretical developments determine the effect of the geometric and nonlocal constitutive rela...

  3. Contributions to the theory of incomplete tension bay

    Science.gov (United States)

    Schapitz, E

    1937-01-01

    The present report offers an approximate theory for the stress and deformation condition after buckling of the skin in reinforced panels and shells loaded in simple shear and compression and under combined stresses. The theory presents a unified scheme for stresses of these types. It is based upon the concept of a nonuniform stress distribution in the metal panel and its marked power of resistance against compressive stresses ("incomplete" tension bay).

  4. Tensions in setting health care priorities for South Africa's children.

    OpenAIRE

    Landman, W A; Henley, L D

    1998-01-01

    The new South African constitution commits the government to guarantee "basic health services" for every child under 18. Primary health care for pregnant women and children under six and elements of essential primary health care have received priority. At present, there is little analysis of the moral considerations involved in making choices about more advanced or costly health care which may, arguably, also be "basic". This paper illustrates some of the tensions in setting priorities for a ...

  5. Measurement of the angle of superficial tension by images

    Science.gov (United States)

    Yanez M., Javier; Alonso R., Sergio

    2006-02-01

    When a liquid is deposited on a surface, this one form a certain angle with respect to the surface, where depending on its value, it will conclude that so hard it is his adhesion with the surface. By means of the analysis of images we looked for to measure this angle of superficial tension. In order to make this measurement, we propose a technique by means of projective transformations and one method of regression to estimation parameters to conic fitting.

  6. Interfacial tension change due to asphaltene flocculation in recombined oils

    Energy Technology Data Exchange (ETDEWEB)

    Carrier, H.; Pauly, J.; Daridon, J.L. [Univ. de Pau, Pau Cedex (France). Laboratoire des Fluides Complexes; Mejia, A. [Univ. de Pau, Pau Cedex (France). Laboratoire des Fluides Complexes; Univ. Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of). Facultad de Ciencias; Castillo, J. [Univ. Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of). Facultad de Ciencias

    2008-07-01

    Asphaltenes found in reservoirs fluids may dissolve as colloidal aggregates in crude oils. The aggregates might destabilize as a result of changes in both temperature and pressure, resulting in flocculation of asphaltenes. The insolubility of asphaltenes can cause major problems at different stages of oil production, such as deposition and flow blockage. In order to evaluate the risk of asphaltene formation and to design techniques to prevent asphaltene deposits, it is necessary to measure and predict the conditions of flocculation throughout the pressures encountered from reservoir to surface conditions. To date, most asphaltene stability studies have been conducted at atmospheric pressure for dead oils by adding precipitating solvents. However the relationship of these stability tests with asphaltene flocculation due to the decompression of live oil in reservoir or production conditions is not fully established. Accurate measurements on both atmospheric and field conditions are needed. In order to address this problem, a high-pressure device using refractive index measurements and a filtration technique was designed to measure onset of asphaltene flocculation in live oils. The capacity of the device was also extended to investigate the evolution of the interfacial tension between crude oil and gases or immiscible liquids such as water, at pressures up to 70 MPa. Interfacial tension was measured by axisymmetric drop shape analysis of a pendant oil drop. The study found that a relationship exists between the discontinuity in the trend of the superficial tension as a function of the pressure and the threshold of asphaltenes aggregation due to decompression. The study provided evidence of the effect of asphaltenes flocculation on the interfacial tension. 2 refs.

  7. Surface tension: Floater clustering in a standing wave

    Science.gov (United States)

    Falkovich, G.; Weinberg, A.; Denissenko, P.; Lukaschuk, S.

    2005-06-01

    How do waves affect the distribution of small particles that float on water? Here we show that drifting small particles concentrate in either the nodes or antinodes of a standing wave, depending on whether they are hydrophilic or hydrophobic, as a result of a surface-tension effect that violates Archimedes' law of buoyancy. This clustering on waves may find practical application in particle separation and provides insight into the patchy distribution on water of, for example, plastic litter or oil slicks.

  8. Dissipative Particle Dynamics of Tension-induced Membrane Fusion

    OpenAIRE

    Grafmueller, Andrea; Lipowsky, Reinhard; Shillcock, Julian C.

    2009-01-01

    Abstract Recent studies of tension-induced membrane fusion using dissipative particle dynamics (DPD) simulations are briefly reviewed. The stochastic nature of the fusion process makes it necessary to simulate a large number of fusion attempts in order to obtain reliable fusion statistics and to extract meaningful values for the fusion probability and the average fusion times. All successful fusion events follow the same pathway. In this fusion pathway, configurations of individual...

  9. Dependence of film tension on the thickness of smectic films.

    Science.gov (United States)

    Jaquet, R; Schneider, F

    2003-02-01

    The film tension tau of free standing S(A) films has been measured for films with thicknesses between 2 and 150 layers. There is a clear increase of tau with the thickness for very thin films and a nonlinear slower increase for high thickness. The nonlinearity depends on the amount of liquid crystal accessible to the meniscus of the film during the drawing process. Several models are discussed that describe these effects. PMID:12636700

  10. 33 CFR 147.809 - Mars Tension Leg Platform safety zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Mars Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.809 Mars Tension Leg Platform safety zone. (a) Description. The Mars Tension Leg Platform (Mars TLP) is located at position...

  11. 33 CFR 147.811 - Ram-Powell Tension Leg Platform safety zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ram-Powell Tension Leg Platform... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.811 Ram-Powell Tension Leg Platform safety zone. (a) Description. The Ram-Powell Tension Leg Platform (Ram-Powell TLP) is located...

  12. RESEARCH OF INFLUENCE OF FRONT TENSION AT ROLLING OF PERIODIC PROFILE IN NON-DRIVE ROLLERS

    Directory of Open Access Journals (Sweden)

    L. A. Isayevich

    2012-01-01

    Full Text Available Influence of a forward tension is theoretically investigated at a rolling of the periodic profiles used as elastic elements of spring suspension brackets. The power balance of rolling process with a tension is analyzed. Dependences for definition of a critical corner and size of its increment are received at a rolling with a forward tension.

  13. Quasinormal modes of a black hole localized on a codimension-two brane of finite tension

    International Nuclear Information System (INIS)

    We calculate the quasinormal modes of black holes localized on a 3-brane of finite tension embedded in six-dimensional flat spacetime. Using the WKB approximation, we obtain the frequencies of scalar and gravitational perturbations both analytically and numerically for arbitrary brane tension. We thus extend earlier analytical results which were derived for a brane of small tension

  14. Tensions in implementing the “energy-conservation/carbon-reduction” policy in Taiwanese culture

    International Nuclear Information System (INIS)

    The aim of this study is to investigate the Taiwanese public's perceptions of tensions between the implementation of an energy policy and the practice of traditional culture. The energy policy calls for public actions to conserve energy and reduce carbon emissions. The research participants are 94 people, selected by balancing sexes, ages, and residential areas, from a wide range of vocations. The research data were collected by semi-structured interview with the participants individually. Interview questions were designed to elicit the participants' constructs, beliefs, behaviours, and tensions in relation to energy policy and traditional culture. Data analysis was performed based on a qualitative methodology by the procedure of open coding, theme finding, constant comparison, and theory generation. The analysis identifies four tensions: (1) tensions in knowledge bases between energy conservation and carbon reduction, (2) tensions in lifestyles between having and being, (3) tensions in social systems between authority and conformity, and (4) tensions in creation boundaries between technology and nature. The themes underlying the four tensions are uncertainty, pleasure, power, and control, respectively. Solutions to the four tensions may include practical knowledge, pragmatic idealism, hierarchical collaboration, and sustainable innovation. - Highlights: ► Tensions occur between energy policy and traditional culture. ► Tensions occur in knowledge, life, society, and creation in Taiwan. ► The themes of the four tensions are uncertainty, pleasure, power, and control

  15. 33 CFR 147.817 - Sir Douglas Morpeth Tension Leg Platform safety zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Sir Douglas Morpeth Tension Leg... HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.817 Sir Douglas Morpeth Tension Leg Platform safety zone. (a) Description. The Sir Douglas Morpeth Tension Leg Platform...

  16. The idea of animal welfare - developments and tensions

    DEFF Research Database (Denmark)

    Sandøe, Peter; Jensen, Karsten Klint

    2013-01-01

    This paper focuses on developments and tensions within the idea of animal welfare. There is divergence among those who believe in the idea of animal welfare. First, we discuss what it takes for farm animal welfare to be good enough. How far should society go beyond the starting point of the Bramb....... Finally, the role of economic considerations is considered, given that animal production takes place in a global market with free trade between countries with various standards of animal welfare.......This paper focuses on developments and tensions within the idea of animal welfare. There is divergence among those who believe in the idea of animal welfare. First, we discuss what it takes for farm animal welfare to be good enough. How far should society go beyond the starting point...... of the Brambell Committee, which was to prevent avoidable suffering? Secondly, we turn to the tricky question of how welfare should be distributed between animals. Here, a tension within the concept of animal welfare, between a focus on the indivudual animal and on the herd, flock or shoal, is pointed out...

  17. Precipitating and relieving factors of migraine versus tension type headache

    Directory of Open Access Journals (Sweden)

    Haque Badrul

    2012-08-01

    Full Text Available Abstract Background To determine the differences of precipitating and relieving factors between migraine and tension type headache. Methods This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. Results In this study, the female patients predominated (67%. Most of the patients were within 21–30 years age group (58.6%. About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH patients. But significant difference was demonstrated for fatigue (p  Conclusion The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs.

  18. Large deflection analysis of a tension-foil bearing

    Science.gov (United States)

    Elrod, David A.

    1996-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are as follows: rolling or sliding contact within the bearing has life-limiting consequences; and REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's. CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contacts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exist for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. Recently, a new tension-foil bearing configuration has been proposed for turbomachinery applications.

  19. Surface tension-affected laminar film condensation problems

    International Nuclear Information System (INIS)

    Following Nusselt there were few developments in the theory of laminar film condensation until the advent of digital computers in the 1950s. Approximations used by Nusselt, namely neglect of inertia, convection and surface shear stress (for the free convection case) were then found to give very accurate results for the normal practical range of vapour-to-surface temperature difference. Subsequent developments treated the gas phase and dealt with superheated vapour, condensation in the presence of a non-condensing gas and condensation of mixtures. The temperature discontinuity at the vapour-liquid interface has been studied experimentally and theoretically since the 19th century and more recently in the 1960s by experiments using liquid metals. In the present paper the focus is on the condensate film and, in particular, the role played by surface tension which is important for condensation on finned surfaces and in microchannels, owing to abrupt changes in curvature of the condensing surface. The way in surface tension affects condensation heat transfer and difficulties which arise are first illustrated by reference to condensation on a smooth horizontal tube, where the effect of surface tension on heat transfer is minimal. Practically more relevant cases of condensation in microchannels and on finned surfaces and are then discussed and recent results presented

  20. Surface tension dominates insect flight on fluid interfaces.

    Science.gov (United States)

    Mukundarajan, Haripriya; Bardon, Thibaut C; Kim, Dong Hyun; Prakash, Manu

    2016-03-01

    Flight on the 2D air-water interface, with body weight supported by surface tension, is a unique locomotion strategy well adapted for the environmental niche on the surface of water. Although previously described in aquatic insects like stoneflies, the biomechanics of interfacial flight has never been analysed. Here, we report interfacial flight as an adapted behaviour in waterlily beetles (Galerucella nymphaeae) which are also dexterous airborne fliers. We present the first quantitative biomechanical model of interfacial flight in insects, uncovering an intricate interplay of capillary, aerodynamic and neuromuscular forces. We show that waterlily beetles use their tarsal claws to attach themselves to the interface, via a fluid contact line pinned at the claw. We investigate the kinematics of interfacial flight trajectories using high-speed imaging and construct a mathematical model describing the flight dynamics. Our results show that non-linear surface tension forces make interfacial flight energetically expensive compared with airborne flight at the relatively high speeds characteristic of waterlily beetles, and cause chaotic dynamics to arise naturally in these regimes. We identify the crucial roles of capillary-gravity wave drag and oscillatory surface tension forces which dominate interfacial flight, showing that the air-water interface presents a radically modified force landscape for flapping wing flight compared with air.