Energy saving in agricultural pumping equipment; Ahorro de energia en equipos de bombeo agricola

Energy Technology Data Exchange (ETDEWEB)

Acosta Torres, R Aracely [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1994-12-31

This paper analyses the current state of the pumping equipment for agricultural irrigation in Mexico. Because of being of the vertical centrifugal turbine type pumps, the most commonly utilized for this service, the study has been focussed into this equipment, obtaining efficiency and consumption scenarios, as well as the potential energy saving existing in this sector. [Espanol] En el presente articulo se analiza el estado actual de los equipos de bombeo para riego agricola en Mexico, al ser las bombas centrifugas verticales tipo turbina, las mas comunmente utilizadas para este servicio, el estudio ha sido enfocado a estos equipos, obteniendose los escenarios de eficiencias y consumos, asi como, el potencial de ahorro energetico existente en este sector.

Energy saving in agricultural pumping equipment; Ahorro de energia en equipos de bombeo agricola

Energy Technology Data Exchange (ETDEWEB)

Acosta Torres, R. Aracely [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1993-12-31

This paper analyses the current state of the pumping equipment for agricultural irrigation in Mexico. Because of being of the vertical centrifugal turbine type pumps, the most commonly utilized for this service, the study has been focussed into this equipment, obtaining efficiency and consumption scenarios, as well as the potential energy saving existing in this sector. [Espanol] En el presente articulo se analiza el estado actual de los equipos de bombeo para riego agricola en Mexico, al ser las bombas centrifugas verticales tipo turbina, las mas comunmente utilizadas para este servicio, el estudio ha sido enfocado a estos equipos, obteniendose los escenarios de eficiencias y consumos, asi como, el potencial de ahorro energetico existente en este sector.

Análisis de ahorro energético en iluminación LED industrial: Un estudio de caso

Directory of Open Access Journals (Sweden)

Ana Serrano-Tierz

2015-01-01

Full Text Available El presente estudio muestra el ahorro económico y las ventajas medioambientales que supone la iluminación industrial con tecnología LED. Se ha planteado un estudio de caso en el que luminarias de halogenuros metálicos han sido sustituidas por luminarias LED. Para validar la sustitución de luminarias con halogenuros metálicos de 400W por LED de 200W, se han efectuado las simulaciones luminotécnicas y mediciones de campo mediante luxómetro. Los resultados obtenidos indican que ambas luminarias son equiparables obteniendo un importante ahorro energético cercano al 50%. Esta investigación demuestra que la tecnología LED ofrece soluciones de iluminación de alto rendimiento que optimizan el ahorro energético reduciendo a su vez costes de mantenimiento con un coste total de propiedad significativamente menor, incrementando la esperanza de vida útil de las luminarias. Desde el punto de vista medioambiental supone una importante reducción en emisiones de CO2 y eliminación de residuos tóxicos como el mercurio.

Estimated potential of energy saving and reduction of the demand commercial buildings illumination; Potencial estimado de ahorro de energia y reduccion de la demanda en iluminacion de edificios comerciales

Energy Technology Data Exchange (ETDEWEB)

Hernandez Gomez, Victor Hugo; Morillon Galvez, David [Posgrado en Energetica de la DEPFI-UNAM, Mexico, D. F. (Mexico)

1999-07-01

In this paper the estimated energy saving potential in illumination, the energy end use and the technology used in commercial buildings of different use is analyzed. Estimation that departs from information of the Fideicomiso para el Ahorro de Energia (FIDE) demonstrative cases, presents the energy saving and the demand reduction in a sample of 29 buildings, among which are shopping malls, hospitals, schools, hotels, restaurants and public buildings in which energy saving programs have been carried out, with measures such as the cleaning of the luminaries and its replacement for more efficient ones. The average saving obtained is of 21.81%, in the following areas: illumination, air conditioning and others. In addition, in a sample of 4 buildings, it was observed that before applying the energy saving programs, two of them did not fulfill with the norm NOM-007-1995 (electric power density in interior lighting systems W/m{sup 2}) and later did fulfill the values and criteria of the norm. [Spanish] En el presente trabajo se analiza el potencial estimado de ahorro de energia en iluminacion, el uso final de la energia y la tecnologia empleada en edificios comerciales de uso distinto. Estimacion que parte de la informacion de los casos demostrativos del Fideicomiso para el Ahorro de Energia (FIDE), se presenta el ahorro y reduccion de la demanda en una muestra de 29 edificios, entre los que se tienen centros comerciales, hospitales, escuelas, hoteles, restaurantes y edificios publicos en los cuales se ha llevado a cabo programas de ahorro de energia, con medidas como la limpieza de las luminarias y su remplazo por otros mas eficientes. El ahorro promedio obtenido es de 21.81%, en las siguientes areas: iluminacion, aire acondicionado y otros. Ademas, en una muestra de 4 edificios, se observo que antes de aplicar los programas de ahorro de energia, dos no cumplian con la norma NOM-007-ENER-1995 (densidad de potencia electrica en alumbrado interior W/m{sup 2}) y

Energy saving based on the reduction of losses in the transmission and distribution of the power generated incrementing the transmission capacities by means of the use of direct current; Ahorro de energia basado en la reduccion de perdidas en la transmision y redistribucion de la generacion al ampliar las capacidades de transmision por medio del empleo de la transmision en corriente directa

Energy Technology Data Exchange (ETDEWEB)

Meraz Ateca, E.; Alanis Rodriguez, J.P.; Salinas Barrera, H.; Arechiga Rodriguez, L.D.; Guerrero Garza, J.J. [Comision Federal de Electricidad (CFE) (Mexico)

1995-12-31

alternating current terminal is recovered from the power lines and there will not be generation restrictions because of the unavailability of alternating current power lines; the achieved reliability is not evaluated, but it will be another benefit. The other option proposed for the project of utilization of power lines with direct current, consists in modifying or using the tie that will be constructed for the Rio Escondido Thermal Electric Station to the Northern Zone and that will operate in parallel with the alternating current network. This project provides the benefits of saving losses of about 20 MW. It is also achieved the increase in effective transmission capacity towards the Northern Zone, due to the fact that it will be Also available a controlled power mean, which facilitates the dispatch functions and re-distribution of power flows in the alternating current network. This tie is proposed of 500 MW operating in bi-polar form at least of 400 KV and reaching up to the Chihuahua Zone, allowing besides the re-dispatching of units to the Northern Zone in counting with greater capacity of effective transmission. The saving in re-dispatching could be significative; additionally, this tie will free transmission capacity from the Coal Power Stations towards the Monterrey Zone. This paper does not get deeper into the advantages regarding the dynamic behavior of the electric system in operating these ties in direct current, but they are not less important, since they can contribute with great benefits to the system during disturbance or emergency conditions. [Espanol] El presenta trabajo propone el empleo de la tecnologia de transmision en corriente directa, que proporciona un ahorro de perdidas de orden del 50% al transmitir la misma cantidad de potencia que la linea energizada en corriente alterna, asi como el contar con una mayor capacidad de transmision, dado que la limitante en la linea trabajando en corriente directa esta dada por su capacidad termica. El aspecto del

Energy saving based on the reduction of losses in the transmission and distribution of the power generated incrementing the transmission capacities by means of the use of direct current; Ahorro de energia basado en la reduccion de perdidas en la transmision y redistribucion de la generacion al ampliar las capacidades de transmision por medio del empleo de la transmision en corriente directa

Energy Technology Data Exchange (ETDEWEB)

Meraz Ateca, E; Alanis Rodriguez, J P; Salinas Barrera, H; Arechiga Rodriguez, L D; Guerrero Garza, J J [Comision Federal de Electricidad (CFE) (Mexico)

1996-12-31

alternating current terminal is recovered from the power lines and there will not be generation restrictions because of the unavailability of alternating current power lines; the achieved reliability is not evaluated, but it will be another benefit. The other option proposed for the project of utilization of power lines with direct current, consists in modifying or using the tie that will be constructed for the Rio Escondido Thermal Electric Station to the Northern Zone and that will operate in parallel with the alternating current network. This project provides the benefits of saving losses of about 20 MW. It is also achieved the increase in effective transmission capacity towards the Northern Zone, due to the fact that it will be Also available a controlled power mean, which facilitates the dispatch functions and re-distribution of power flows in the alternating current network. This tie is proposed of 500 MW operating in bi-polar form at least of 400 KV and reaching up to the Chihuahua Zone, allowing besides the re-dispatching of units to the Northern Zone in counting with greater capacity of effective transmission. The saving in re-dispatching could be significative; additionally, this tie will free transmission capacity from the Coal Power Stations towards the Monterrey Zone. This paper does not get deeper into the advantages regarding the dynamic behavior of the electric system in operating these ties in direct current, but they are not less important, since they can contribute with great benefits to the system during disturbance or emergency conditions. [Espanol] El presenta trabajo propone el empleo de la tecnologia de transmision en corriente directa, que proporciona un ahorro de perdidas de orden del 50% al transmitir la misma cantidad de potencia que la linea energizada en corriente alterna, asi como el contar con una mayor capacidad de transmision, dado que la limitante en la linea trabajando en corriente directa esta dada por su capacidad termica. El aspecto del

Aplicación de la Contabilidad de Costos en las Cajas Rurales de Ahorro y Crédito en el Perú, Arequipa - 2013

OpenAIRE

Pacheco Zegarra, Edward Víctor

2017-01-01

El presente trabajo de investigación busca determinar el grado de aplicación de la contabilidad de costos en las Cajas Rurales de Ahorro y Crédito en el Perú. ENUNCIADO “APLICACIÓN DE LA CONTABILIDAD DE COSTOS EN LA CAJAS RURALES DE AHORRO Y CRÉDITO EN EL PERÚ, AREQUIPA – 2013” La variable a investigar fue la aplicación de la contabilidad de costos cuyos indicadores son las generalidades de la aplicación de la contabilidad de costos, objetivos de la contabilidad de costos...

Integral programs of energy conservation (exergy) in the petroleum industry; Programas integrales de ahorro de energia (exergia) en la industria petrolera

Energy Technology Data Exchange (ETDEWEB)

Rivero Rodriguez, R. [Instituto Mexicano del Petroleo (IMP), Mexico, D. F. (Mexico)

1995-12-31

This paper presents some of the fundamental issues related to energy conservation programs in general and to the petroleum industry in particular with the purpose of integrating them both, that is, considering not only the energy issues, but also the ecological and economical aspects. This is achieved by using the two fundamental laws of thermodynamics (the science that studies energy, its characteristics, and its transformations) through the use of the exergy concept, which is a measure of the energy quality and of its withdrawal with respect to the environment. The origins of the present-day technologies, regarding energy conservation, the short, medium and long term general strategies and the implementation stages of the integral programs of energy conservation are presented, and it concludes with a series of general policies aimed at making the energy conservation programs more congruent with the maintenance of a sustainable development. [Espanol] En este trabajo se presentan algunos aspectos fundamentales relacionados con los programas de ahorro de energia en general, y en la industria petrolera en particular, con objeto de lograr que los mismos sean integrales, es decir que consideren no solo los aspectos puramente energeticos, sino tambien los aspectos ecologicos y economicos. Esto se logra utilizando conjuntamente las dos leyes fundamentales de la termodinamica (la ciencia que estudia la energia, sus caracteristicas y sus transformaciones), mediante la utilizacion del concepto de exergia, que es una medida de la calidad de la energia y de su alejamiento con respecto al medio ambiente. Se presentan los origenes de las tendencias tecnologicas actuales en materia de ahorro de energia, las estrategias generales a corto, mediano y largo plazos y las etapas en la implementacion de programas integrales de ahorro de energia, para concluir con una serie de politicas generales tendientes a lograr que los programas de ahorro de energia sean congruentes con el

Integral programs of energy conservation (exergy) in the petroleum industry; Programas integrales de ahorro de energia (exergia) en la industria petrolera

Energy Technology Data Exchange (ETDEWEB)

Rivero Rodriguez, R [Instituto Mexicano del Petroleo (IMP), Mexico, D. F. (Mexico)

1996-12-31

This paper presents some of the fundamental issues related to energy conservation programs in general and to the petroleum industry in particular with the purpose of integrating them both, that is, considering not only the energy issues, but also the ecological and economical aspects. This is achieved by using the two fundamental laws of thermodynamics (the science that studies energy, its characteristics, and its transformations) through the use of the exergy concept, which is a measure of the energy quality and of its withdrawal with respect to the environment. The origins of the present-day technologies, regarding energy conservation, the short, medium and long term general strategies and the implementation stages of the integral programs of energy conservation are presented, and it concludes with a series of general policies aimed at making the energy conservation programs more congruent with the maintenance of a sustainable development. [Espanol] En este trabajo se presentan algunos aspectos fundamentales relacionados con los programas de ahorro de energia en general, y en la industria petrolera en particular, con objeto de lograr que los mismos sean integrales, es decir que consideren no solo los aspectos puramente energeticos, sino tambien los aspectos ecologicos y economicos. Esto se logra utilizando conjuntamente las dos leyes fundamentales de la termodinamica (la ciencia que estudia la energia, sus caracteristicas y sus transformaciones), mediante la utilizacion del concepto de exergia, que es una medida de la calidad de la energia y de su alejamiento con respecto al medio ambiente. Se presentan los origenes de las tendencias tecnologicas actuales en materia de ahorro de energia, las estrategias generales a corto, mediano y largo plazos y las etapas en la implementacion de programas integrales de ahorro de energia, para concluir con una serie de politicas generales tendientes a lograr que los programas de ahorro de energia sean congruentes con el

Scenarios simulation for the conservation and efficient use of energy, using passive control measures; Simulacion de escenarios de ahorro y uso eficiente de energia, utilizando medidas de control pasivo

Energy Technology Data Exchange (ETDEWEB)

Ramos, G.; Heard, Ch.; Sanchez Viveros, A. [Instituto de Investigaciones Electricas,Cuernavaca (Mexico)

1997-12-31

Every one involved with the conservation and efficient use of electric energy, has listened in reiterative occasions to the causes that changed the conventional mentality at the beginning of the seventies. Nevertheless, there are many persons that still ignore that by using the energy rationally, their costs are significantly reduced, their comfort is enhanced and the environmental problems are minimized. Specifically, in the domestic sector, from the figures reported by the Comision Federal de Electricidad (CFE) in 1996, the electric energy sold was 28,410 Gwh, that is, 23.4% of the total consumption (121,579 Gwh). Table 1 presents the average by tariff in the national domestic sector, which shows that 20% of the electricity consumed was required for environmental conditioning (air conditioning, evaporative coolers and electric fans). The above figures quantitatively show that there is a strong impact in the consumption of electric energy due to weather conditions. For this reason, currently the Comision Nacional de Ahorro de Energia (CONAE) and the Fideicomiso para el Ahorro de Energia (FIDE) are promoting standards and projects to propitiate the rationalization in the use of energy, besides of achieving the improvement of thermal comfort conditions. One more case would be the Fideicomiso para el Aislamiento Termico de la Vivienda en Mexicali (FIPATERM), which promotes the financing of saving measures and efficient energy use in cities with extreme climate. This paper describes the strategy that was followed by the Instituto de Investigaciones Electricas (IIE), for the development of the human and material infrastructure, that has allowed the sustainment of several projects in the saving and efficient use of energy in CFE, CONAE, FIDE, FIPATERM and the Lawrence Berkeley National Laboratory (LBNL), concretely in relationship with the thermal analysis of dwellings. [Espanol] Todos aquellos relacionados con el ahorro y el uso eficiente de la energia electrica, han

Scenarios simulation for the conservation and efficient use of energy, using passive control measures; Simulacion de escenarios de ahorro y uso eficiente de energia, utilizando medidas de control pasivo

Energy Technology Data Exchange (ETDEWEB)

Ramos, G; Heard, Ch; Sanchez Viveros, A [Instituto de Investigaciones Electricas,Cuernavaca (Mexico)

1998-12-31

Every one involved with the conservation and efficient use of electric energy, has listened in reiterative occasions to the causes that changed the conventional mentality at the beginning of the seventies. Nevertheless, there are many persons that still ignore that by using the energy rationally, their costs are significantly reduced, their comfort is enhanced and the environmental problems are minimized. Specifically, in the domestic sector, from the figures reported by the Comision Federal de Electricidad (CFE) in 1996, the electric energy sold was 28,410 Gwh, that is, 23.4% of the total consumption (121,579 Gwh). Table 1 presents the average by tariff in the national domestic sector, which shows that 20% of the electricity consumed was required for environmental conditioning (air conditioning, evaporative coolers and electric fans). The above figures quantitatively show that there is a strong impact in the consumption of electric energy due to weather conditions. For this reason, currently the Comision Nacional de Ahorro de Energia (CONAE) and the Fideicomiso para el Ahorro de Energia (FIDE) are promoting standards and projects to propitiate the rationalization in the use of energy, besides of achieving the improvement of thermal comfort conditions. One more case would be the Fideicomiso para el Aislamiento Termico de la Vivienda en Mexicali (FIPATERM), which promotes the financing of saving measures and efficient energy use in cities with extreme climate. This paper describes the strategy that was followed by the Instituto de Investigaciones Electricas (IIE), for the development of the human and material infrastructure, that has allowed the sustainment of several projects in the saving and efficient use of energy in CFE, CONAE, FIDE, FIPATERM and the Lawrence Berkeley National Laboratory (LBNL), concretely in relationship with the thermal analysis of dwellings. [Espanol] Todos aquellos relacionados con el ahorro y el uso eficiente de la energia electrica, han

Píldora de Crecimiento Económico: Modelos de crecimiento económico con tasas de ahorro constantes

OpenAIRE

López Díaz, Julio

2015-01-01

Claves para obtener, con carácter genérico, la ecuación fundamental de crecimiento en un modelo con tasa de ahorro constante. Departamento de Fundamentos del Análisis Económico e Historia e Instituciones Económicas

El efecto del alfabetismo financiero en el ahorro para el retiro en México.

OpenAIRE

F. Alejandro Villagómez; Alayn González

2014-01-01

En este trabajo analizamos si es posible incrementar el ahorro para el retiro por medio de alfabetismo financiero en México. Con información de la Encuesta Nacional de los Niveles de Vida de los Hogares 2005 (ENNVIH-2) construimos un índice de alfabetizo financiero siguiendo la metodología propuesta por Atkinson y Messy (2012) que considera tres factores: conocimiento, actitudes y comportamiento financiero. Nuestros resultados sugieren que el alfabetismo financiero tiene un impacto positivo e...

Propuesta de incorporación del Segmento Pymes en las operaciones de crédito de la Cooperativa de Ahorro y Crédito 29 de Octubre

OpenAIRE

Ríos Páliz, Cristina Araceli

2015-01-01

En el proyecto que se presenta a continuación permite aplicar una metodología de análisis que brinde a la Cooperativismo de Ahorro y Crédito “29 de Octubre”, incorporar operaciones de crédito del segmento Comercial Pymes a su cartera de crédito cumpliendo lo establecido por la Superintendencia de Bancos, normativa que será transitoria para la Superintendencia de Economía Popular y Solidaria hasta que defina sus políticas de control y seguimiento para las Cooperativas de Ahorro y Crédito por ...

Electric energy saving and its impact in the mining industry; El ahorro de energia electrica y su impacto en la industria minera

Energy Technology Data Exchange (ETDEWEB)

Urteaga Dufour, Jose Antonio [Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE), Mexico, D. F. (Mexico)

1994-12-31

In this paper are shown the most important results of the energy diagnosis performed in some representative industries of the mining industry, where opportunity areas were detected in electric energy saving, starting from those measures that do not require investment up to the ones that require medium investment, recoverable in less than two years terms as a maximum and with electric energy saving ranging from 10% to 25%. [Espanol] En este trabajo, se presentan los resultados mas importantes, obtenidos en el diagnostico energetico realizado en algunas empresas representativas de la rama de la mineria, en donde se detectaron areas de oportunidad de ahorro de energia electrica que van desde aquellas medidas que no requieren inversiones hasta las que requieren medianas inversiones, recuperables en menos de dos anos como maximo y con ahorros de energia que van desde un 10% hasta un 25%.

Electric energy saving and its impact in the mining industry; El ahorro de energia electrica y su impacto en la industria minera

Energy Technology Data Exchange (ETDEWEB)

Urteaga Dufour, Jose Antonio [Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE), Mexico, D. F. (Mexico)

1993-12-31

In this paper are shown the most important results of the energy diagnosis performed in some representative industries of the mining industry, where opportunity areas were detected in electric energy saving, starting from those measures that do not require investment up to the ones that require medium investment, recoverable in less than two years terms as a maximum and with electric energy saving ranging from 10% to 25%. [Espanol] En este trabajo, se presentan los resultados mas importantes, obtenidos en el diagnostico energetico realizado en algunas empresas representativas de la rama de la mineria, en donde se detectaron areas de oportunidad de ahorro de energia electrica que van desde aquellas medidas que no requieren inversiones hasta las que requieren medianas inversiones, recuperables en menos de dos anos como maximo y con ahorros de energia que van desde un 10% hasta un 25%.

Strategies for energy saving in warm climate dwellings; Estrategias de ahorro de energia para viviendas en clima calido

Energy Technology Data Exchange (ETDEWEB)

Pilatowsky, I [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico (Mexico); Ramos Niembro, Gaudencio [Comision Nacional para el Ahorro de Energia -CONAE (Mexico); Morillon, David [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico (Mexico); Oskam, A. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico (Mexico)

2008-04-15

The domestic sector consumes almost one quarter of the national electrical energy. In order to reduce in an important manner the power consumption in dwellings there is an integral alternative based on three elements: the bio-climatic design, the saving and efficient use of the energy in equipment and apparatuses, and the use of centralized air conditioning systems. Besides saving the electrical and thermal power consumption, with this scheme, comfort conditions are pretended to be reached in dwellings and, contributing at the same time, to the diminution of polluting emissions. [Spanish] El sector domestico consume casi una cuarta parte de la energia electrica nacional. Con objeto de reducir de manera importante el consumo de energia en las viviendas, se presenta una alternativa integral, basada en tres elementos: el diseno bioclimatico, el ahorro y uso eficiente de la energia en equipos y aparatos, y la utilizacion de sistemas de climatizacion centralizados. Ademas del ahorro en el consumo de energia electrica y termica, con este esquema se pretende alcanzar condiciones de confort en las viviendas y, al mismo tiempo, contribuir a la disminucion de emisiones contaminantes.

Las puzolanas y el ahorro energético en los materiales de construcción

Directory of Open Access Journals (Sweden)

Soria Santamaría, Francisco

1983-09-01

Full Text Available This discussion commences with some general comments on the energy crisis and its impact on the cement industry, with the corresponding coal reconversion problems. Three factors are highlighted where saving has been centered: technological process, raw materials and finished product, emphasizing the interest of latter which includes incorporating active additions in Portland cement. A quick review then follows about pozzolanas, their origin, definitions and classification. Their chemical composition is underlined, and the concept of pozzolanic activity is described. Later on, pozzolanic cements, their most significant properties and the advantages of using pozzolana are explained. After a lengthy description about possible applications of pozzolanas and pozzolanic cements, the conclusion reviews current trends in international standards for such cements and possible evolution in consumption of additions by the year 2000, with a view to saving more energy, without impairing the essential properties of the cement.

Comienza esta exposición con unas consideraciones generales sobre la crisis energética y su impacto en la industria cementera, con los correspondientes problemas de reconversión al carbón. Se mencionan los tres aspectos en que se ha centrado el ahorro energético: proceso tecnológico, materias primas y producto acabado, destacando el interés de este último que incluye la incorporación de adiciones activas al cemento portland. Se hace a continuación un rápido comentario sobre puzolanas, su origen, definiciones y clasificación. Se destaca la composición química de las mismas y se desarrolla el concepto de actividad puzolánica. Más tarde se hace una exposición sobre cementos puzolánicos, sus propiedades más destacadas y las ventajas que supone el empleo de la puzolana. Tras una exposición amplia de las posibles aplicaciones de las puzolanas y cementos puzolánicos, se concluye comentando las tendencias

Object Detection: Current and Future Directions

Directory of Open Access Journals (Sweden)

Rodrigo eVerschae

2015-11-01

Full Text Available Object detection is a key ability required by most computer and robot vision systems. The latest research on this area has been making great progress in many directions. In the current manuscript we give an overview of past research on object detection, outline the current main research directions, and discuss open problems and possible future directions.

Nissan Mexicana. First place in national prize of electrical energy saving 1998; Nissan Mexicana. Primer lugar en premio nacional de ahorro de energia electrica 1998

Energy Technology Data Exchange (ETDEWEB)

Gonzalez S, Enrique [Nissan Mexicana, S.A. de C.V., Planta Civac, Cuernavaca, Mor. (Mexico)

1999-07-01

For Plant CIVAC of Nissan Mexicana, the energy saving began in the year of 1990. From then, different programs have been developed using different strategies for energy saving until arriving at the Benchmarking with other Plants of Japan, which represents a new challenge, since it opened up an area of opportunity of saving in processes that generally were known in detail as far as to its main function (to make vehicles with quality, cost and opportunity of delivery), but the parameter of energy consumption of by unit and its benefits in relation to the cost was unknown. This was endorsed by the high Direction and began with the optimization of training for the operation of each equipment with the involvement of the user (Production), the engineering area (that establishes the process) and the maintenance area. We designed a general program where the basic activities were included, such as the general and special activities. Each one of them fulfilled its objective, but the special activities took us to the optimization of the processes, finding excess of energy in the design conditions. [Spanish] Para Planta CIVAC de Nissan Mexicana, el ahorro de energia se inicio en el ano de 1990. A partir de entonces se han desarrollado programas de ahorro de energia usando estrategias diferentes hasta llegar al Benchmarking con otras Plantas de Japon, el cual representa un reto nuevo, ya que puso al descubierto una area de oportunidad de ahorro en los procesos que por lo general se conocian a detalle en cuanto a la funcion principal (hacer vehiculos con calidad, costo y oportunidad de entrega), pero se desconocia el parametro de consumo de energia por unidad y sus beneficios en relacion con el costo. Esto fue avalado por la alta Direccion y se inicio con la capacitacion de la optimizacion de la operacion de cada equipo y se involucro al usuario (Produccion), al area de ingenieria (que establece el proceso) y al area de mantenimiento. Elaboramos un programa general donde se

A three-port direct current converter

DEFF Research Database (Denmark)

2016-01-01

circuit comprises a connection between the at least one input direct current source and the at least one storage battery, the primary side circuit configured for operating as a buck converter; a second magnetic component serially coupled to the first single magnetic component, wherein the first and second...... magnetic components are configured to perform a voltage step-up, wherein the secondary side circuit comprises a connection between the at least one storage battery and at least one load, the secondary side configured for operating as a tapped boost converter; wherein the three-port direct current converter......The three-port direct current converter comprising: at least one input direct current source; at least one storage battery; a primary side circuit; a secondary side circuit; a first single magnetic component shared by the primary side circuit and the secondary side circuit, wherein the primary side...

Adjustable direct current and pulsed circuit fault current limiter

Science.gov (United States)

Boenig, Heinrich J.; Schillig, Josef B.

2003-09-23

A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

Utilization of the computational technic for the promotion and diffusion of the energy conservation practice; Utilizacion de tecnicas computacionales para promocionar y difundir el ahorro de energia

Energy Technology Data Exchange (ETDEWEB)

Kemper Valverde, N. [Laboratorio de Inteligencia Artificial, Instituto de Ingenieria, UNAM, Mexico D. F. (Mexico)

1995-12-31

In this paper are presented the developments obtained through the application of the new computational technologies in the diffusion and promotion tasks of energy efficient use and conservation. The most relevant aspects are described of three multimedia courses that were designed in order to increase the possibilities of offering personal training in efficient energy technic, as well as to have on hand totally open consulting and interactive tools. The courses that are described are: ``Design of Energy Conservation Programs for the Industry``, ``Energy Conservation in Combustion Equipment`` and ``Energy Cogeneration Technologies.`` On another subject, an analysis is also made of the possibilities for the development and application of expert systems that advise and give support to the work of technicians and engineers dedicated to energy conservation. The main characteristics of an expert system to give support to the energy analysis of lighting industrial systems, malls, buildings and hotels are also described. [Espanol] En este trabajo se presentan los desarrollos obtenidos por la aplicacion de las tareas de difusion y promocion del uso eficiente y ahorro de energia. Se describen los aspectos mas relevantes de tres cursos multimedia que fueron disenados con el objeto de incrementar las posibilidades de brindar capacitacion individualizada en tecnicas energeticas eficientes, asi como de contar con herramientas de consulta totalmente abiertas e interactivas. Los cursos que se describen son: ``Diseno de Programas de Ahorro de Energia en la Industria,`` ``Ahorro de Energia en Equipos de Combustion`` y ``Tecnologias de Cogeneracion de Energia.`` Por otro lado, tambien se hace un analisis de las posibilidades para el desarrollo y aplicacion de sistemas expertos que asesoren y apoyen el trabajo de tecnicos e ingenieros dedicados al ahorro de energia. Se describen las caracteristicas principales de un sistema experto disenado para brindar apoyo en analisis energeticos

Utilization of the computational technic for the promotion and diffusion of the energy conservation practice; Utilizacion de tecnicas computacionales para promocionar y difundir el ahorro de energia

Energy Technology Data Exchange (ETDEWEB)

Kemper Valverde, N [Laboratorio de Inteligencia Artificial, Instituto de Ingenieria, UNAM, Mexico D. F. (Mexico)

1996-12-31

In this paper are presented the developments obtained through the application of the new computational technologies in the diffusion and promotion tasks of energy efficient use and conservation. The most relevant aspects are described of three multimedia courses that were designed in order to increase the possibilities of offering personal training in efficient energy technic, as well as to have on hand totally open consulting and interactive tools. The courses that are described are: ``Design of Energy Conservation Programs for the Industry``, ``Energy Conservation in Combustion Equipment`` and ``Energy Cogeneration Technologies.`` On another subject, an analysis is also made of the possibilities for the development and application of expert systems that advise and give support to the work of technicians and engineers dedicated to energy conservation. The main characteristics of an expert system to give support to the energy analysis of lighting industrial systems, malls, buildings and hotels are also described. [Espanol] En este trabajo se presentan los desarrollos obtenidos por la aplicacion de las tareas de difusion y promocion del uso eficiente y ahorro de energia. Se describen los aspectos mas relevantes de tres cursos multimedia que fueron disenados con el objeto de incrementar las posibilidades de brindar capacitacion individualizada en tecnicas energeticas eficientes, asi como de contar con herramientas de consulta totalmente abiertas e interactivas. Los cursos que se describen son: ``Diseno de Programas de Ahorro de Energia en la Industria,`` ``Ahorro de Energia en Equipos de Combustion`` y ``Tecnologias de Cogeneracion de Energia.`` Por otro lado, tambien se hace un analisis de las posibilidades para el desarrollo y aplicacion de sistemas expertos que asesoren y apoyen el trabajo de tecnicos e ingenieros dedicados al ahorro de energia. Se describen las caracteristicas principales de un sistema experto disenado para brindar apoyo en analisis energeticos

Aplicación del impuesto a las transacciones financieras ITF y su incidencia en el servicio de ahorro del Banco de la Nación Región Puno 2004 - 2007.

OpenAIRE

Caceres Quispe, Hector Omar

2010-01-01

El presente trabajo de investigación titulado "APLICACIÓN DEL IMPUESTO A LAS TRANSACCIONES FINANCIERAS ITF Y SU INCIDENCIA EN EL SERVICIO DE AHORRO DEL BANCO DE LA NACIÓN REGION PUNO 2004-2007". Tiene como objetivo general determinar la incidencia del Impuesto a las Transacciones Financieras- ITF, en el servicio de ahorro del Banco de la Nación Región Puno. Los impuestos se obtienen de los ingresos generados en la economía, tanto por la interacción de las personas como por las empresas (en ac...

El ahorro fiscal de las cooperativas en el impuesto sobre Sociedades en España

OpenAIRE

Herrero Blasco, Aurelio

2015-01-01

[ES] El objeto de este artículo es medir el ahorro fiscal que procede del Impuesto sobre Sociedades de las cooperativas en España para el período 1999-2009. La metodología utilizada ha sido un estudio longitudinal en el cual se ha analizado la recaudación total en España por tipos impositivos. Se ha analizado el Impuesto sobre Sociedades en general y posteriormente el Tipo Impositivo Efectivo (TIE) de las Sociedades Cooperativas. Los resultados más importantes son la constatación de diferenc...

Cost-Benefit of the energy saving in the bioclimatic designs; Costo-Beneficio del ahorro de energia en los disenos bioclimaticos

Energy Technology Data Exchange (ETDEWEB)

Lopez P, J. Manuel A. [Doble Dos Soluciones de Negocios, S.A. de C.V., Mexico, D.F. (Mexico); Morillon G, David; Rodriguez V, Luis [Instituto de Ingenieria de la UNAM, Mexico, D.F. (Mexico)

1999-07-01

Tools and criteria for the Cost-Benefit analysis from the energy saving in bioclimatic designs (BD) are presented, for which, a reference project is established and the costs and benefits of energy saving in BD with base in that project are evaluated. A case study is presented taking as reference the traditional design of the air conditioning of a building and with this base the estimation of cost-benefit of the same building is made, but with passive systems. The tools used are those that allow to consider related resources such as time and money; in that sense, are used criteria such as: Present value (PV), Equivalent Annual Cost (EAC) and the Cost of the Conserved Energy (CCE). The costs related to the construction, maintenance and operation of the design are taken into account. The differences between the reference design and the BD, established from the application of these criteria, allow to evaluate the economic margin of the BD as far as operation and maintenance is concerned. Finally the CCE of the bioclimatic measures is evaluated as an initiative of energy saving and the present value is calculated of the energy saving in the entire useful life of a bioclimatic design. [Spanish] Se presentan herramientas y criterios para el analisis Costo-Beneficio del ahorro de energia en disenos bioclimaticos (DB), para lo cual, se establece un proyecto de referencia y se evaluan los costos y beneficios del ahorro de energia en DB con base en ese proyecto. Se presenta el estudio de un caso tomando como referencia el dise tradicional de la climatizacion de un edificio y con base en este, se realiza la estimacion de costos y beneficios del mismo edificio, pero con sistemas pasivos. Las herramientas usadas, son aquellas que permiten considerar recursos relacionados como son tiempo y dinero; en ese sentido, se usan criterios como: Valor Presente (VP), Costo Anual Equivalente (CAE) y el Costo de la Energia Conservada (CEC). Se toman en consideracion los costos relacionados

Determinantes del perfil de ahorro en Colombia : una estimación para hogares e individuos

OpenAIRE

Daza Báez, Nancy Aireth

2011-01-01

En este documento se presenta un análisis de los determinantes del perfil de ahorro para hogares e individuos con el objetivo de contrastar la Hipótesis de Ciclo de Vida, utilizando la metodología expuesta en Deaton y Paxson (2000a y 2000b) con datos de la Encuesta Nacional de Ingresos y Gastos (ENIG) para los periodos 1984-1985, 1994-1995 y 2006-2007. Se encontró que para el análisis por hogar no hay evidencia que determine el cumplimiento de la Hipótesis del Ciclo de Vida, mientras que para...

Enhanced motor learning with bilateral transcranial direct current stimulation: Impact of polarity or current flow direction?

Science.gov (United States)

Naros, Georgios; Geyer, Marc; Koch, Susanne; Mayr, Lena; Ellinger, Tabea; Grimm, Florian; Gharabaghi, Alireza

2016-04-01

Bilateral transcranial direct current stimulation (TDCS) is superior to unilateral TDCS when targeting motor learning. This effect could be related to either the current flow direction or additive polarity-specific effects on each hemisphere. This sham-controlled randomized study included fifty right-handed healthy subjects in a parallel-group design who performed an exoskeleton-based motor task of the proximal left arm on three consecutive days. Prior to training, we applied either sham, right anodal (a-TDCS), left cathodal (c-TDCS), concurrent a-TDCS and c-TDCS with two independent current sources and return electrodes (double source (ds)-TDCS) or classical bilateral stimulation (bi-TDCS). Motor performance improved over time for both unilateral (a-TDCS, c-TDCS) and bilateral (bi-TDCS, ds-TDCS) TDCS montages. However, only the two bilateral paradigms led to an improvement of the final motor performance at the end of the training period as compared to the sham condition. There was no difference between the two bilateral stimulation conditions (bi-TDCS, ds-TDCS). Bilateral TDCS is more effective than unilateral stimulation due to its polarity-specific effects on each hemisphere rather than due to its current flow direction. This study is the first systematic evaluation of stimulation polarity and current flow direction of bi-hemispheric motor cortex TDCS on motor learning of proximal upper limb muscles. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Diseño de un sistema de gestión de seguridad de la información para Cooperativas de Ahorro y Crédito en base a la norma ISO 27001

OpenAIRE

Mantilla Guerra, Aníbal Rubén

2009-01-01

209 hojas : ilustraciones, 29 x 21 cm + CD-ROM 2254 En esta Tesis se diseñó un Sistema de Gestión de Seguridad de la Información para Cooperativas de Ahorro y Crédito, en base a la norma ISO 27001, la Ley de la Superintendencia de Bancos y Seguros, la Ley de Cooperativas de Ahorro y Crédito, considerando además, su evolución y problemática en el Sistema Financiero Nacional. De manera metodológica, científica y objetiva, se muestra como identificar, evaluar y gestionar el riesgo, en Coopera...

Creación de un marco de control para la administración del riesgo operativo relacionado con la tecnologias de la información como modelo para las cooperativas de ahorro y crédito del Ecuador

OpenAIRE

Brito Domínguez, Jimmy Arturo; Echeverria Briones, Pedro Fabricio

2009-01-01

Creación de un marco de control para la administración del riesgo operativo relacionado con la tecnologías de la informacion como modelo para las cooperativas de ahorro y credito del Ecuador Creación de un marco de control para la administración del riesgo operativo relacionado con la tecnologías de la informacion como modelo para las cooperativas de ahorro y credito del Ecuador

Social responsibility and social security: The foundation of caja de pensiones para la vejez y de ahorros

OpenAIRE

Argandoña, Antonio; Moreno, Carlos M.; Sola, Joan M.

2009-01-01

The concept of Corporate Social Responsibility (CSR) is not new. Over the course of time, many entrepreneurs have created and developed companies, with a strong sense of ethical and social responsibility. This paper presents an example of how CSR was conceived and put into practice when Caja de Pensiones para la Vejez y de Ahorros was created in Barcelona in 1905, following the life and ideas of its founder, Francesc Moragas, a lawyer with a deep commitment to social action and a successful c...

Determinantes del isomorfismo institucional de las sociedades cooperativas de ahorro y préstamos en México

OpenAIRE

Lara Gómez, Graciela; Pérez Sosa, Felipe A.

2015-01-01

El propósito del presente trabajo es establecer si las sociedades cooperativas de ahorro y préstamo se hacen isomorfas a la banca formal en México; debido a que tales entidades tradicionalmente han operado en un entorno de informalidad, pero últimamente han transitado hacia la formalización como consecuencia de las exigencias legales impuestas por entidades regulatorias. Para este fin, el presente estudio se llevó a cabo con una orientación metodológica mixta, en la que los resultados obtenid...

Saving of electrical energy in educative institutions; Ahorro de energia electrica en instituciones educativas

Energy Technology Data Exchange (ETDEWEB)

Castillo Medina, Gabino [Instituto Tecnologico y de Estudios Superiores de Monterrey Campus Estado de Mexico, (Mexico)

2003-07-01

The present work looks for integrating the actions of energy saving that can be applied in educative institutions, not concerning the level or size of the same ones. The actions go from questions of making aware the student population until those involved in the change in the operation, migration and implementation of technology. Without overlooking the formative aspect that the educative institutions have and the social commitment of these last ones. It is important that the saving measures have as mission to achieve a culture focussed to make efficient use of the resources, of energy as well as material. This culture must be born from the classrooms and must transform the way to be and act of the student community that will permeate itself with the society. Let us remember that actions are worth more than words, so the educative institutions must preach with the example. [Spanish] El presente trabajo busca integrar las acciones de ahorro de energia que pueden ser aplicadas en instituciones educativas, no importando el nivel o tamano de las mismas. Las acciones van desde cuestiones de concienciar a la poblacion estudiantil hasta las que involucran el cambio en la operacion, migracion e implementacion de tecnologia. Sin perder de vista el aspecto formativo que tienen las instituciones educativas y el compromiso social de estas ultimas. Es importante que las medidas de ahorro tengan como mision lograr una cultura enfocada a hacer uso eficiente de los recursos, tanto energeticos como materiales. Dicha cultura debe nacer desde las aulas y debe transformar la manera de ser y actuar, de la comunidad estudiantil que se permeara con la sociedad. Recordemos que las acciones valen mas que las palabras, asi que las instituciones educativas deben predicar con el ejemplo.

Introduction criteria and concepts on energy saving in the technical standards for electric installations; Introduccion de criterios y conceptos de ahorro de energia en las normas tecnicas para instalaciones electricas

Energy Technology Data Exchange (ETDEWEB)

Rincon Nader, Jorge A [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1993-12-31

The project Introduction Criteria and Concepts on Energy Saving in the Technical Standards for electric installations, is described, whose immediate objective is to recommend and in some cases regulate the use of energy saving equipment and devices and the adoption of attitudes and procedures that convey into saving, and the rational and efficient use of the electric energy. [Espanol] Se describe el proyecto Introduccion de Criterios y Conceptos de Ahorro de Energia en las Normas Tecnicas para instalaciones electricas, que tiene como objetivo inmediato recomendar, y en algunos casos reglamentar el uso de equipos y dispositivos ahorradores y la adopcion de actitudes y procedimientos que conduzcan a un ahorro y uso racional y eficiente de la energia electrica.

Introduction criteria and concepts on energy saving in the technical standards for electric installations; Introduccion de criterios y conceptos de ahorro de energia en las normas tecnicas para instalaciones electricas

Energy Technology Data Exchange (ETDEWEB)

Rincon Nader, Jorge A. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1992-12-31

The project Introduction Criteria and Concepts on Energy Saving in the Technical Standards for electric installations, is described, whose immediate objective is to recommend and in some cases regulate the use of energy saving equipment and devices and the adoption of attitudes and procedures that convey into saving, and the rational and efficient use of the electric energy. [Espanol] Se describe el proyecto Introduccion de Criterios y Conceptos de Ahorro de Energia en las Normas Tecnicas para instalaciones electricas, que tiene como objetivo inmediato recomendar, y en algunos casos reglamentar el uso de equipos y dispositivos ahorradores y la adopcion de actitudes y procedimientos que conduzcan a un ahorro y uso racional y eficiente de la energia electrica.

Energy saving in the management of the BIMBO group distribution fleet; Ahorro de energia en la operacion de la flotilla de distribucion del grupo BIMBO

Energy Technology Data Exchange (ETDEWEB)

Mexico, BIMBO

2005-07-01

In this work BIMBO demonstrates that in order to save energy it is necessary to invest in equipment, parts, research and people. This is why they got involved in the task of developing the projects of fuel cells participating with universities, associations, Secretaria de Energia, Comision Nacional de Ahorro de Energia (National Commission for Energy Saving) (CONAE) and the National Council for Science and Tecnologia (CONACYT), through financial supports with projects of mechanisms of clean development (Kyoto Protocol). For doing it they had to prove different types of fuels: biodiesel, hydrogen, alcohol and hybrids; for them to determine the most profitable and practical thus reducing the energy consumption. With the saving of fuels and lubricants in our vehicles, a greater yield in the company is obtained. [Spanish] En este trabajo BIMBO demuestra que para ahorrar energia hay que invertir en equipo, partes, investigacion y gente. Es por eso que se dieron a la tarea de desarrollar los proyectos de celdas de combustible, participando con universidades, asociaciones, la Secretaria de Energia, la Comision Nacional para el Ahorro de Energia (CONAE) y el Consejo Nacional para la Ciencia y Tecnologia (CONACYT), a traves de apoyos financieros con proyectos de mecanismos de desarrollo limpio (protocolo de Kyoto). Para ello tuvieron que probar diferentes tipos de combustibles: biodiesel, hidrogeno, alcohol e hibridos, para determinar los mas rentables y practicos y asi reducir el consumo de energia; con el ahorro de combustibles y lubricantes en nuestros vehiculos, logrando una mayor rentabilidad en la empresa.

Compact fluorescent lamps, innovation for electricity saving; Lamparas fluorescentes compactas, innovacion para el ahorro de electricidad

Energy Technology Data Exchange (ETDEWEB)

Rivera, Fernando [Fideicomiso para el Ahorro de Energia Electrica (Mexico); Camacho P, Wendolin E; Villalobos Alarcon, German [Phillips Lighting Mexico (Mexico)

2007-01-15

An extremely important resource is electricity because it has provided illumination for homes, buildings and cities in the absence of natural light. Therefore, the human being is considering to save this valuable resource by using sophisticated light bulbs. At the end of the 70's the compact fluorescent lamps appeared. In this article we can disclose the advantages and disadvantages of this technology, and how some years later of its invention, those lamps satisfied the client expectations, due to its cost, electricity saving, longer lifetime, use possibilities, and technological improvements. We can also know how Federal Electricity Commission (CFE) and The Trust Fund for Electric Energy Savings (FIDE) supported a project to favor these lamps to be in the Mexican market. [Spanish] La electricidad es un recurso de suma importancia porque ha contribuido a la iluminacion de casas, edificios y ciudades, ante la ausencia de luz natural, es por ello que se ha buscado ahorrar este recurso tan preciado con el uso de lamparas sofisticadas. Una tecnologia que aparecio a finales de los anos 70 fueron las lamparas fluorescentes compactas. En este articulo encontramos sus ventajas y desventajas, y como despues de algunos anos de su creacion comenzaron a llenar las expectativas del cliente gracias a su costo, ahorro de electricidad, mayor tiempo de vida, posibilidades de aplicacion y mejoras tecnologicas. Asi mismo podemos conocer, el proyecto que se hizo para que esta tecnologia entrara al mercado mexicano, con el apoyo de la Comision Federal de Electricidad (CFE) y del Fideicomiso para el Ahorro de Energia Electrica (FIDE).

Electric power saving potential due to domestic refrigerators replacement; Potencial de ahorro de energia electrica por el reemplazo de refrigeradores domesticos

Energy Technology Data Exchange (ETDEWEB)

Peralta Solorio, Jose Luis [Fideicomiso para el Ahorro de Energia Electrica (Mexico)]. E-mail: jose.peralta@cfe.gob.mx

2006-04-15

In Mexico the second most used electrical appliance is: refrigerator. Owing to its use, it would be a promising option for electric power saving. In Guadalajara, Reynosa and Tampico it was performed a study with the aim of launching a project to replace the old refrigerators with new ones which are more effective and less expensive. Since the refrigerators cost and the electrical invoicing saving, the electric appliance change is profitable. To expect with this replacement more than eight million of refrigerators manufactured before 1997 will be changed. [Spanish] El refrigerador es el segundo electrodomestico mas utilizado a nivel nacional, esto permite que debido a su uso sea una opcion prometedora para el ahorro de energia electrica. Se hizo un estudio en Guadalajara, Reynosa y Tampico con el fin de lanzar un proyecto para sustituir los refrigeradores viejos por unos nuevos que sean mas eficaces y menos costosos. Por el costo de los refrigeradores y el ahorro en la facturacion electrica, el cambio de electrodomestico es rentable, de esta manera se espera que los mas de ocho millones de refrigeradores fabricados antes de 1997 que existen en el pais sean cambiados.

El ahorro de los hogares colombianos: un analisis a partir de las encuestas de ingresos y gastos

OpenAIRE

Castañeda Cordy, Alberto

2003-01-01

En Colombia el seguimiento a la evolución del ahorro privado y de las variables que lo determinan se ha realizado a partir de la información agregada de las cuentas nacionales. No existe aproximación alguna a partir de datos individuales que consideren el influjo de las características socioeconómicas de las familias sobre esa variable. Esto obedece, en gran parte, a la ausencia de datos de encuestas que sigan la evolución de los ingresos y los consumos de los hogares.Mientras la información ...

Ahorro de consumo de agua, aplicando técnicas de riego en jardines de la UNAC

OpenAIRE

Sánchez Hernández, Jaime Eloy

2013-01-01

La implementación del Proyecto "AHORRO DE CONSUMO DE AGUA, APLICANDO TECNICAS DE RIEGO EN JARDINES DE LA UNAC, con un sistema tecnificado de riego, específicamente por aspersión, se lograría ahorrar agua aproximadamente en un 50%. Además de personal de jardinería provista de mangueras (sistema de inundación) se dedicarían a otras labores que mejoren los jardines de la UNAC. Como corolario se tiene que no solo se ahorraría agua (pago de consumo a la empresa SEDAPAL), sino que al personal se...

Incidencia del modelo de otorgamiento de cartera en la gestión del riesgo de crédito de la cooperativa de ahorro y crédito Bola Amarilla de la ciudad de Ibarra

OpenAIRE

Ayala Pupiales, Sandra Maribel

2017-01-01

Evaluar la incidencia del modelo de otorgamiento de cartera en la gestión del riesgo de crédito de la cooperativa de ahorro y crédito Bola Amarilla de la ciudad de Ibarra. El presente trabajo proporciona estrategias, políticas y procedimientos con el fin de dar cumplimiento a las resoluciones emitidas por el órgano de supervisión y control para las cooperativas de ahorro y crédito Superintendencia de Economía Popular y Solidaria del Ecuador y la Junta Política de Regulación Financiera y Mo...

Energy saving in Bellota Mexico S.A. de C.V.; Ahorro de energia en Bellota Mexico S.A de C.V.

Energy Technology Data Exchange (ETDEWEB)

Salazar Lopez, Jose Albeiro [Bellota Mexico S.A. de C.V. (Mexico)

2003-07-01

The present article intends to make a general description of the different activities that were developed in Bellota Mexico S.A. de C.V. during year 2001 and which lead to obtaining the national prize of energy saving granted by the Comision Federal de Electricidad (CFE) and the Fideicomiso para el Ahorro de Energia Electrica (FIDE). In the executed actions stands out an entirely coordinated program that includes: lighting systems, motors, refrigeration systems, transformers, special projects (settling tanks), capacitors, compressed air pipeline, induction furnaces, machinery in general, maximum demand control, preventive maintenance, measuring systems, operational and organizational systems. In all these subjects a fast description is made of the performed actions and the obtained results. It is mentioned in addition the importance of making a power diagnosis and the use of historical data for the planning of the strategies to follow. Also reference is made of the use of appropriate technology that considers the use of high-energy efficiency equipment, such as motors, lamps, compressors, etc. Finally an evaluation is made of the obtained results where the improvement of the electrical parameters stands out such as: reduction of the power index in 35.06%, reduction of the maximum demand in 11.94%, increase of the power factor from 93.53% in 98.21%. The obtained results demonstrate that investing in energy saving it is a good business. [Spanish] El presente trabajo tiene por objeto hacer una descripcion general de las diferentes actividades que se desarrollaron en Bellota Mexico S.A. de C.V. durante el ano 2001 y que condujeron a la obtencion del premio nacional de ahorro de energia otorgado por la Comision Federal de Electricidad (CFE) y el Fideicomiso para el Ahorro de Energia Electrica (FIDE). En las acciones ejecutadas se destaca todo un programa coordinado que abarca: sistemas de iluminacion, motores, sistemas de refrigeracion, transformadores, proyectos

Stability analysis of direct current control in current source rectifier

DEFF Research Database (Denmark)

Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...

EOP Current Magnitude and Direction

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These data contain shipboard current magnitudes and directions collected in the Pacific, both pelagic and near shore environments. Data is collected using an RD...

El Ahorro de los hogares colombianos: un análisis a partir de las encuestas de ingresos y gastos

OpenAIRE

Castañeda Cordy, Alberto

2004-01-01

Consultable des del TDX Títol obtingut de la portada digitalitzada En Colombia el seguimiento a la evolución del ahorro privado y de las variables que lo determinan se ha realizado a partir de la información agregada de las cuentas nacionales. No existe aproximación alguna a partir de datos individuales que consideren el influjo de las características socioeconómicas de las familias sobre esa variable. Esto obedece, en gran parte, a la ausencia de datos de encuestas que sigan la evoluci...

Análisis de la eficiencia en las cooperativas de ahorro y crédito en Colombia, mediante la utilización de la técnica de Análisis de Datos Envolvente DEA, periodo 2008-2011

OpenAIRE

Moreno Sierra, Vivian Carolina; Rey Huertas, Luis Eduardo

2015-01-01

La presente estudio pretende analizar la eficiencia en las cooperativas de ahorro y crédito en Colombia, mediante la utilización de la técnica de análisis de datos envolvente (DEA); el trabajo investigativo es importante analizar al subsector cooperativo de ahorro y crédito para el periodo 2008-2011 debido a que este subsector es el más dinámico del sector cooperativo. La identificación de las cooperativas eficientes requiere de la aplicación de una técnica no paramétrica mediante el análisis...

Experiences of energy saving and co-generation projects; Experiencias de proyectos de ahorro de energia y cogeneracion

Energy Technology Data Exchange (ETDEWEB)

Alvarez Barajas, Alberto [Heat and Power Systems, S.A. de C.V., Mexico D.F. (Mexico)

2005-07-01

In this document are presented the successful projects of energy saving and co-generation that Heat and Power Systems, S.A. de C.V. has made in diverse industries. The investment recovery periods have been smaller to 18 months. The projects have been made for different companies within Mexican Republic. [Spanish] Se presentan los casos exitosos de proyectos de ahorro de energia y cogeneracion que Heat and Power Systems, S.A. de C.V. ha realizado en diversas industrias cuyo periodo de recuperacion de la inversion han sido menores a 18 meses. Los proyectos han sido realizados para distintas empresas dentro de la Republica Mexicana.

Carbon Bonds and the saving of energy; Bonos de carbono y el ahorro de energia

Energy Technology Data Exchange (ETDEWEB)

Alvarez Ramirez, Alejandro [NovaEnergia (Mexico)

2005-07-01

This document deals with the development of the carbon bond project, the energy saving and the entry into force of the Kyoto Protocol at a world-wide level. In this project Mexico opts for a development model in which the economic growth brakes ties with the discharge of greenhouse effect gases and in which the progress does not mean more damages to our planet. [Spanish] Este documento trata sobre el desarrollo del proyecto de bonos de carbono, ahorro de energia y la entrada en vigor del Protocolo de Kyoto a nivel mundial, en el cual Mexico opta por un modelo de desarrollo en el que el crecimiento economico esta desvinculado de la emision de gases de efecto invernadero y en donde el progreso no signifique mas danos a nuestro planeta.

Energy conservation in ice manufacturing; Ahorro de energia en la fabricacion de hielo

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

This paper shows the results of the energy diagnosis study for ice manufacturing industries. The identified opportunities for conservation and efficient use of energy have allowed the reduction of the electric bill, modernizing at the same time, its installations and addressing inherent aspects of the use of energy producing items; in which the estimated investments are recovered in its major part in a period of a year, the goodness of the investments propitiate the growth and competitiveness required in these days. [Espanol] En este documento se exponen los resultados del estudio del diagnostico energetico para industrias productoras de hielo. Las oportunidades de ahorro y uso eficiente de energia identificadas, han permitido reducir la facturacion energetica, a la par de modernizar sus instalaciones y atender aspectos inherentes al uso de energeticos; en lo cual las inversiones estimadas se recuperan en su mayoria en un ano, las bondades de las inversiones propician un crecimiento y competitividad requerida en estos dias.

Cálculo del ahorro de energía por menor fricción

Directory of Open Access Journals (Sweden)

Pedro Albarracín Aguillón

2004-01-01

Full Text Available En este artículo se expone como disminuir costos de operación (menor consumo de energía, costos de mantenimiento y pérdidas de producción de equipos, mediante el control de los diferentes fenómenos de la fricción en mecanismos lubricados. Para hacer esto posible es necesario conocer las condiciones criticas de trabajo de los mismos, a que tipo de lubricación corresponden, y que clase lubricante requiere, para así calcular los valores de los coeficientes de fricción de los lubricantes que se están empleando y compararlos con los de otros lubricantes que pueden dar lugar a ahorros de energía y mantenimiento. Además se presentan algunos ejemplos tomados de casos reales, que confirman que con una buena implementación de un programa de tribologia se obtienen resultados satisfactorios desde el punto de vista económico.

Energy conservation in ice manufacturing; Ahorro de energia en la fabricacion de hielo

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-12-31

This paper shows the results of the energy diagnosis study for ice manufacturing industries. The identified opportunities for conservation and efficient use of energy have allowed the reduction of the electric bill, modernizing at the same time, its installations and addressing inherent aspects of the use of energy producing items; in which the estimated investments are recovered in its major part in a period of a year, the goodness of the investments propitiate the growth and competitiveness required in these days. [Espanol] En este documento se exponen los resultados del estudio del diagnostico energetico para industrias productoras de hielo. Las oportunidades de ahorro y uso eficiente de energia identificadas, han permitido reducir la facturacion energetica, a la par de modernizar sus instalaciones y atender aspectos inherentes al uso de energeticos; en lo cual las inversiones estimadas se recuperan en su mayoria en un ano, las bondades de las inversiones propician un crecimiento y competitividad requerida en estos dias.

Direct current power delivery system and method

Science.gov (United States)

Zhang, Di; Garces, Luis Jose; Dai, Jian; Lai, Rixin

2016-09-06

A power transmission system includes a first unit for carrying out the steps of receiving high voltage direct current (HVDC) power from an HVDC power line, generating an alternating current (AC) component indicative of a status of the first unit, and adding the AC component to the HVDC power line. Further, the power transmission system includes a second unit for carrying out the steps of generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit, detecting a presence or an absence of the added AC component in the HVDC power line, and determining the status of the first unit based on the added AC component.

El back office de capital humano y su impacto en la optimización de procesos y generación de ahorros en costos de servicios en Arca Continental, sucursal Salta, durante el segundo semestre del año 2016

OpenAIRE

Giménez Perri, Solana

2017-01-01

248 p. il. El tema de la presente investigación fue el back office de capital humano y su impacto en la optimización de procesos y generación de ahorros en costos de servicios en Arca Continental, sucursal Salta, durante el segundo semestre del año 2016. Se trata de un estudio de tipo descriptivo que buscó establecer asociaciones entre tres dimensiones de análisis: back office de capital humano, optimización de procesos y generación de ahorros. En el trabajo de campo se entrevistó a inf...

Los determinantes a largo plazo y su contribución a la tasa de ahorro de los hogares españoles en el período 1985-2016 || Long-term determinants and its contribution to Spanish household saving rate during the period 1985-2016

Directory of Open Access Journals (Sweden)

de Andrés Mosquera, Andrés

2017-12-01

Full Text Available El trabajo estudia el comportamiento de la tasa de ahorro de los hogares en el período de 1985 a 2016. Se examinan las variables que la literatura considera que determinan la tasa de ahorro a largo plazo: renta, riqueza, desempleo, crédito y endeudamiento, ahorro público, estructura de la población, prestaciones sociales, tipos de interés y precios. Tras revisar la cointegración de las variables elegidas, proponemos cuatro especificaciones de la tasa de ahorro en función de sus determinantes a largo plazo: la renta permanente, la riqueza, el desempleo, el crédito, la tasa de dependencia y las prestaciones sociales. En el marco del modelo de corrección de error, contrastamos complementariamente la cointegración de las variables que confirman la validez del modelo. Los resultados muestran la especial relevancia a largo plazo de la tasa de dependencia que, como variable demográfica estructural, permite prever en cierta medida la evolución de la tasa de ahorro. Las prestaciones sociales, que muestran la importancia a largo plazo del sistema de prestaciones público, junto con el crédito y el desempleo, determinan la tasa de ahorro a largo plazo en consonancia con la fase del ciclo económico. La renta laboral-permanente incide sobre la tasa de ahorro especialmente en los cambios profundos de ciclo. La repercusión a largo plazo de la riqueza es de menor magnitud. || The paper studies the behavior of the household saving rate during the period from 1985 to 2016. We examine the variables considered by the literature to determine the long-term saving rate: Income, wealth, unemployment, credit and indebtedness, public savings, population structure, social benefits, interest rates and prices. In the framework of the error correction model, we contrast the cointegration of the variables by means of four specifications for the saving rate according to its long-term determinants: Permanent income, wealth, unemployment, credit, dependency rate

Transcranial cerebellar direct current stimulation and transcutaneous spinal cord direct current stimulation as innovative tools for neuroscientists

Science.gov (United States)

Priori, Alberto; Ciocca, Matteo; Parazzini, Marta; Vergari, Maurizio; Ferrucci, Roberta

2014-01-01

Two neuromodulatory techniques based on applying direct current (DC) non-invasively through the skin, transcranial cerebellar direct current stimulation (tDCS) and transcutaneous spinal DCS, can induce prolonged functional changes consistent with a direct influence on the human cerebellum and spinal cord. In this article we review the major experimental works on cerebellar tDCS and on spinal tDCS, and their preliminary clinical applications. Cerebellar tDCS modulates cerebellar motor cortical inhibition, gait adaptation, motor behaviour, and cognition (learning, language, memory, attention). Spinal tDCS influences the ascending and descending spinal pathways, and spinal reflex excitability. In the anaesthetised mouse, DC stimulation applied under the skin along the entire spinal cord may affect GABAergic and glutamatergic systems. Preliminary clinical studies in patients with cerebellar disorders, and in animals and patients with spinal cord injuries, have reported beneficial effects. Overall the available data show that cerebellar tDCS and spinal tDCS are two novel approaches for inducing prolonged functional changes and neuroplasticity in the human cerebellum and spinal cord, and both are new tools for experimental and clinical neuroscientists. PMID:24907311

Daylight-saving time: Consumption and demand saving and pollutants emission reduction; El cambio de horario de verano: Ahorros en consumo y demanda, y reduccion de contaminantes

Energy Technology Data Exchange (ETDEWEB)

Ramos, Gaudencio; Diaz, Rodrigo; Fiscal, Raul; Alquicira, Claudia; Martinez, Serafin; Maqueda, Martin [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

This paper presents some of the saving obtained in demand and in fuels with the daylight-saving time, as well as the main aspects considered to make an evaluation of it. [Espanol] Se presentan los ahorros obtenidos en consumo, demanda y combustibles con el cambio de horario de verano, asi como los principales aspectos considerados para efectuar la evaluacion de los mismos.

Daylight-saving time: Consumption and demand saving and pollutants emission reduction; El cambio de horario de verano: Ahorros en consumo y demanda, y reduccion de contaminantes

Energy Technology Data Exchange (ETDEWEB)

Ramos, Gaudencio; Diaz, Rodrigo; Fiscal, Raul; Alquicira, Claudia; Martinez, Serafin; Maqueda, Martin [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

This paper presents some of the saving obtained in demand and in fuels with the daylight-saving time, as well as the main aspects considered to make an evaluation of it. [Espanol] Se presentan los ahorros obtenidos en consumo, demanda y combustibles con el cambio de horario de verano, asi como los principales aspectos considerados para efectuar la evaluacion de los mismos.

The methodology for the evaluation of the energy saving by the daylight saving time in Mexico; Metodologia para la evaluacion del ahorro de energia debido al cambio de horario durante la epoca del verano

Energy Technology Data Exchange (ETDEWEB)

Ramos Niembro, Gaudencio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1996-12-31

A description is made of the methodology for the evaluation of energy saving by the daylight saving time in Mexico. A mathematical model was developed that would allow the quantitative evaluation of the energy saving by the daylight saving time, through measurements of the consumption of different users from the domestic commercial and industrial sector, considering the various variables that impact the consumption [Espanol] Se describe la metodologia para la evalucion del ahorro de energia por el cambio de horario de verano en Mexico. Se desarrollo un modelo matematico que permitiera evaluar cuantitativamente el ahorro de energia debido al cambio de horario durante la epoca de verano, atraves de mediciones de consumos de los diferentes usuarios de los sectores domestico, comercial e industrial, considerando las diversas variables que impactan en el consumo

The methodology for the evaluation of the energy saving by the daylight saving time in Mexico; Metodologia para la evaluacion del ahorro de energia debido al cambio de horario durante la epoca del verano

Energy Technology Data Exchange (ETDEWEB)

Ramos Niembro, Gaudencio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

A description is made of the methodology for the evaluation of energy saving by the daylight saving time in Mexico. A mathematical model was developed that would allow the quantitative evaluation of the energy saving by the daylight saving time, through measurements of the consumption of different users from the domestic commercial and industrial sector, considering the various variables that impact the consumption [Espanol] Se describe la metodologia para la evalucion del ahorro de energia por el cambio de horario de verano en Mexico. Se desarrollo un modelo matematico que permitiera evaluar cuantitativamente el ahorro de energia debido al cambio de horario durante la epoca de verano, atraves de mediciones de consumos de los diferentes usuarios de los sectores domestico, comercial e industrial, considerando las diversas variables que impactan en el consumo

Diagnóstico al sistema de control interno del área contable Cooperativa Nacional Educativa de Ahorro y Crédito "COONFIE"

OpenAIRE

Quesada Sánchez, Iván Darío; Calderón Gómez, Ramsés Camilo; Saavedra Pinzón, Miguel Antonio

2013-01-01

Presenta el resultado del estudio de evaluación sobre la aplicación y el desarrollo del sistema de control interno, en el área Contable de la Cooperativa Nacional Educativa de Ahorro y Crédito “COONFIE”. Así mismo se busca medir la utilización que ha hecho dicha entidad de la metodología empleada para inspección y vigilancia, el cual ha proporcionado herramientas y acciones complementarias en las entidades aportando desarrollo y crecimiento

Is transcranial direct current stimulation a potential method for improving response inhibition?

Science.gov (United States)

Kwon, Yong Hyun; Kwon, Jung Won

2013-04-15

Inhibitory control of movement in motor learning requires the ability to suppress an inappropriate action, a skill needed to stop a planned or ongoing motor response in response to changes in a variety of environments. This study used a stop-signal task to determine whether transcranial direct-current stimulation over the pre-supplementary motor area alters the reaction time in motor inhibition. Forty healthy subjects were recruited for this study and were randomly assigned to either the transcranial direct-current stimulation condition or a sham-transcranial direct-current stimulation condition. All subjects consecutively performed the stop-signal task before, during, and after the delivery of anodal transcranial direct-current stimulation over the pre-supplementary motor area (pre-transcranial direct-current stimulation phase, transcranial direct-current stimulation phase, and post-transcranial direct-current stimulation phase). Compared to the sham condition, there were significant reductions in the stop-signal processing times during and after transcranial direct-current stimulation, and change times were significantly greater in the transcranial direct-current stimulation condition. There was no significant change in go processing-times during or after transcranial direct-current stimulation in either condition. Anodal transcranial direct-current stimulation was feasibly coupled to an interactive improvement in inhibitory control. This coupling led to a decrease in the stop-signal process time required for the appropriate responses between motor execution and inhibition. However, there was no transcranial direct-current stimulation effect on the no-signal reaction time during the stop-signal task. Transcranial direct-current stimulation can adjust certain behaviors, and it could be a useful clinical intervention for patients who have difficulties with response inhibition.

Transcranial Direct Current Stimulation in Epilepsy.

Science.gov (United States)

San-Juan, Daniel; Morales-Quezada, León; Orozco Garduño, Adolfo Josué; Alonso-Vanegas, Mario; González-Aragón, Maricarmen Fernández; Espinoza López, Dulce Anabel; Vázquez Gregorio, Rafael; Anschel, David J; Fregni, Felipe

2015-01-01

Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation therapy in epilepsy with conflicting results in terms of efficacy and safety. Review the literature about the efficacy and safety of tDCS in epilepsy in humans and animals. We searched studies in PubMed, MedLine, Scopus, Web of Science and Google Scholar (January 1969 to October 2013) using the keywords 'transcranial direct current stimulation' or 'tDCS' or 'brain polarization' or 'galvanic stimulation' and 'epilepsy' in animals and humans. Original articles that reported tDCS safety and efficacy in epileptic animals or humans were included. Four review authors independently selected the studies, extracted data and assessed the methodological quality of the studies using the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions, PRISMA guidelines and Jadad Scale. A meta-analysis was not possible due to methodological, clinical and statistical heterogeneity of included studies. We analyzed 9 articles with different methodologies (3 animals/6 humans) with a total of 174 stimulated individuals; 109 animals and 65 humans. In vivo and in vitro animal studies showed that direct current stimulation can successfully induce suppression of epileptiform activity without neurological injury and 4/6 (67%) clinical studies showed an effective decrease in epileptic seizures and 5/6 (83%) reduction of inter-ictal epileptiform activity. All patients tolerated tDCS well. tDCS trials have demonstrated preliminary safety and efficacy in animals and patients with epilepsy. Further larger studies are needed to define the best stimulation protocols and long-term follow-up. Copyright © 2015 Elsevier Inc. All rights reserved.

Desarrollo de un manual de auditoría informática aplicado a Cooperativas de Ahorro y Crédito

OpenAIRE

Sarango Ontaneda, Carlos Alberto

2013-01-01

La auditoría informática es una función (en ocasiones un servicio) que apoya al trabajo de las unidades de auditoría interna de las Cooperativas de Ahorro y Crédito. Sin embargo, el trabajo a realizarse exige que los profesionales en auditoría informática cumplan con ciertas normas y requerimientos tanto legales como profesionales. El uso de marcos de buenas prácticas, análisis de riesgos y la observación de las normas de auditoría son fundamentales para el desarrollo de las evaluaciones de ...

Frontal transcranial direct current stimulation (tDCS) abolishes list-method directed forgetting.

Science.gov (United States)

Silas, Jonathan; Brandt, Karen R

2016-03-11

It is a point of controversy as to whether directed forgetting effects are a result of active inhibition or a change of context initiated by the instruction to forget. In this study we test the causal role of active inhibition in directed forgetting. By applying cathodal transcranial direct current stimulation (tDCS) over the right prefrontal cortex we suppressed cortical activity commonly associated with inhibitory control. Participants who underwent real brain stimulation before completing the directed forgetting paradigm showed no directed forgetting effects. Conversely, those who underwent sham brain stimulation demonstrated classical directed forgetting effects. We argue that these findings suggest that inhibition is the primary mechanism that results in directed forgetting costs and benefits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Navy Telemedicine: Current Research and Future Directions

National Research Council Canada - National Science Library

Reed, Cheryl

2002-01-01

.... This report reviews military and civilian models for evaluating telemedicine systems in order to determine future directions for Navy telemedicine research within the current funding environment...

Diagnóstico y propuesta de plan de mejoramiento en el área financiera para el Sistema de Cooperativas de Ahorro y Crédito del Segmento Uno, reguladas por la Superintendencia de Economía Popular y Solidaria, durante el período 2011- 2014

OpenAIRE

Pacheco Guevara, Ximena Patricia

2016-01-01

La presente investigación se enfoca en una propuesta de mejora en el área financiera para el sistema de cooperativas de ahorro y crédito del segmento uno, reguladas por la Superintendencia de Economía Popular y Solidaria, durante el período 2011-2014. Bajo este contexto, se revisaron una serie de metodologías aplicadas a nivel internacional, definiendo la creada por el Consejo Mundial de Cooperativas de Ahorro y Crédito WOCCU como la más apropiada, al analizar específicamente cooperativas de ...

Reversal thyristor-relay direct current commutator

International Nuclear Information System (INIS)

Ivanenko, A.I.

1982-01-01

A thyristor-relay commutator used for alteration of the leading magnetic field direction in experiments with polarized neutrons is described. The commutator flowsheet is presented. Thyristors, connected so as to allow the relay trigger operation mode, are used as controllable electronic relay. Two connected in series coils with the total inductance of the order of 0.28 H serve as the electronic relay load. The arc-free current commutation is effected at the moment of the minimal current across the load terminals, which allows to easily reverse the current up to 10 A at a volatage, v <= 150 V. The experience gained within a year of operation has shown that the commutator meets the requirements of reliability and tuning

Current Directional Protection of Series Compensated Line Using Intelligent Classifier

Directory of Open Access Journals (Sweden)

M. Mollanezhad Heydarabadi

2016-12-01

Full Text Available Current inversion condition leads to incorrect operation of current based directional relay in power system with series compensated device. Application of the intelligent system for fault direction classification has been suggested in this paper. A new current directional protection scheme based on intelligent classifier is proposed for the series compensated line. The proposed classifier uses only half cycle of pre-fault and post fault current samples at relay location to feed the classifier. A lot of forward and backward fault simulations under different system conditions upon a transmission line with a fixed series capacitor are carried out using PSCAD/EMTDC software. The applicability of decision tree (DT, probabilistic neural network (PNN and support vector machine (SVM are investigated using simulated data under different system conditions. The performance comparison of the classifiers indicates that the SVM is a best suitable classifier for fault direction discriminating. The backward faults can be accurately distinguished from forward faults even under current inversion without require to detect of the current inversion condition.

Direct currents produced by hf heating of plasma

International Nuclear Information System (INIS)

Klima, R.

1974-01-01

In addition to the well-known diffusion currents, toroidal direct currents arise in h.f. heated plasmas as a result of a momentum transfer from the h.f. field to plasma particles. The estimates of steady-state conditions are given for these currents. Particularly, the possibility of stationary operation of a Tokamak device is analyzed. (author)

Direct Drive Generator for Renewable Power Conversion from Water Currents

International Nuclear Information System (INIS)

Segergren, Erik

2005-01-01

In this thesis permanent magnet direct drive generator for power conversion from water currents is studied. Water currents as a power source involves a number of constrains as well as possibilities, especially when direct drive and permanent magnets are considered. The high power fluxes and low current velocities of a water current, in combination with its natural variations, will affect the way the generator is operated and, flowingly, the appearance of the generator. The work in this thesis can, thus, be categorized into two general topics, generator technology and optimization. Under the first topic, fundamental generator technology is used to increase the efficiency of a water current generator. Under the latter topic, water current generators are optimized to a specific environment. The conclusion drawn from this work is that it is possible to design very low speed direct drive generators with good electromagnetic properties and wide efficiency peak

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

Science.gov (United States)

Kwon, Yong Hyun; Jang, Sung Ho

2012-01-01

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation. PMID:25624815

Zener diode controls switching of large direct currents

Science.gov (United States)

1965-01-01

High-current zener diode is connected in series with the positive input terminal of a dc supply to block the flow of direct current until a high-frequency control signal is applied across the zener diode. This circuit controls the switching of large dc signals.

Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients.

Science.gov (United States)

Kazuta, Toshinari; Takeda, Kotaro; Osu, Rieko; Tanaka, Satoshi; Oishi, Ayako; Kondo, Kunitsugu; Liu, Meigen

2017-08-01

The aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients. Twelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined. The increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance and induced the primacy effect in stroke patients.

Direct current contamination of kilohertz frequency alternating current waveforms.

Science.gov (United States)

Franke, Manfred; Bhadra, Niloy; Bhadra, Narendra; Kilgore, Kevin

2014-07-30

Kilohertz frequency alternating current (KHFAC) waveforms are being evaluated in a variety of physiological settings because of their potential to modulate neural activity uniquely when compared to frequencies in the sub-kilohertz range. However, the use of waveforms in this frequency range presents some unique challenges regarding the generator output. In this study we explored the possibility of undesirable contamination of the KHFAC waveforms by direct current (DC). We evaluated current- and voltage-controlled KHFAC waveform generators in configurations that included a capacitive coupling between generator and electrode, a resistive coupling and combinations of capacitive with inductive coupling. Our results demonstrate that both voltage- and current-controlled signal generators can unintentionally add DC-contamination to a KHFAC signal, and that capacitive coupling is not always sufficient to eliminate this contamination. We furthermore demonstrated that high value inductors, placed in parallel with the electrode, can be effective in eliminating DC-contamination irrespective of the type of stimulator, reducing the DC contamination to less than 1 μA. This study highlights the importance of carefully designing the electronic setup used in KHFAC studies and suggests specific testing that should be performed and reported in all studies that assess the neural response to KHFAC waveforms. Published by Elsevier B.V.

Propuesta de un plan estratégico de marketing para la Cooperativa de Ahorro y Crédito Artesanal de la ciudad de Cuenca

OpenAIRE

Salazar Centeno, Sandra Elizabeth; Toledo Solano, Miriam Alexandra

2008-01-01

La presente tesina, constituye un Plan Estratégico de Marketing para la Cooperativa de Ahorro y Crédito "Artesanal", orientado a contribuir con el desarrollo y bienestar para sus socios. Hoy en día las empresas deben ser proactivas y adelantarse a las necesidades del mercado, esto ayudará a mejorar su imagen, pero para esto, es importante contar con la filosofía empresarial, es decir el tener establecido cual es el norte de le entidad financiera, determinar las metas, objetivos institucion...

Propuesta para la Incorporación del Concepto y la Estructuración del Área de Sostenibilidad en el Fondo Nacional del Ahorro

OpenAIRE

Diazgranados Muñoz, Ana María; Merlano Uribe, María Paula; Zamora Ramírez, Judith Andrea

2014-01-01

En el contexto actual en el que las organizaciones buscan generar acciones que respondan por el impacto que tienen sus actividades y decisiones en su entorno más próximo, se realiza un propuesta de incorporación del concepto de la Responsabilidad Social Empresarial (RSE) para el Fondo Nacional del Ahorro (FNA) con el fin de que la entidad involucre dentro de sus procesos acciones socialmente responsables y a su vez contribuya con el desarrollo sostenible. El documento Propuesta Para La ...

Ahorros en los consumos para enfriamiento de espacios interiores mediante la evaluación de sistemas de protección solar en edificios residenciales en altura. El caso de la "ciudad-oasis" de Mendoza, Argentina

Directory of Open Access Journals (Sweden)

Julieta Balter

2016-06-01

Full Text Available El presente trabajo estudia el comportamiento térmico y energético de edificios residenciales en altura, en el contexto particular de una “ciudad-oasis”. Se plantea como objetivo la definición de sistemas de control solar adecuados en la envolvente para cada tipología material de edificio -másica y liviana- y para cada estrato en altura de las viviendas: debajo y sobre de la copa de los árboles. El monitoreo de viviendas en uso permite validar modelos geométricos (software Energy Plus y simular propuestas de aplicación de elementos de protección solar. Se analizan los ahorros en los consumos para enfriamiento en departamentos en niveles bajos, medios y altos. Los resultados muestran que en el edificio másico, en las viviendas ubicadas debajo de la copa de los árboles, es posible anular las cargas energéticas para enfriamiento mediante el uso de elementos exteriores de protección solar. Mientras que en las viviendas sobre la copa de los árboles, los ahorros energéticos se encuentran entre el 32% y 42%. En el edificio liviano, la aplicación de sistemas de control en departamentos bajo la copa de los árboles alcanza ahorros del orden del 53% y en las viviendas sobre la copa, las reducciones energéticas se encuentran entre el 46% y 54%. Las dimensiones adecuadas de tales elementos pueden generar propuestas posibles de ser transferidas a las normativas locales de edificación. 

Electric power saving in the drinkable water, sewage and sanitation system, La Piedad; Ahorro de energia electrica en el sistema de agua potable, alcantarillado y saneamiento de La Piedad

Energy Technology Data Exchange (ETDEWEB)

Sistema de Agua Potable, Alcantarillado y Saneamiento de la Piedad (Mexico). E-mail: sapaslapiedad@prodigy.net.mx

2006-04-15

In Michoacan, Mexico, a project who seeks to benefice the Municipal public resources was crated in 1994. It would be achieved trough the electric power saving in the public lighting system, and drinkable water pumping and black water, since those activities required the budget biggest part. The program could be developed recently and the saving was significant. In addition the electromechanical efficiency increased in the equipment installation. This work is an example for other States to do something similar that can improve their conditions. [Spanish] En el estado de Michoacan, Mexico se creo un proyecto en el ano de 1994, el cual buscaba beneficiar los recursos publicos municipales, a traves del ahorro de la energia electrica en los sistemas de alumbrado publico y bombeo de agua potable y aguas negras, ya que estas actividades son las que requieren la mayor parte del presupuesto. El programa pudo llevarse a cabo en anos recientes y el ahorro fue significativo, ademas de que aumento la eficiencia electromecanica en los equipos que se instalaron, y esta obra ha servido de ejemplo a otros estados para que realicen algo similar que pueda mejorar su situacion.

Administración estratégica y gobernabilidad en las cooperativas de ahorro y crédito del cantón Portoviejo

OpenAIRE

Dianexy Viviana Carreño

2014-01-01

Las Cooperativas de Ahorro y Crédito (CAC’s) tienen una activa participación en el crecimiento y desarrollo económico del Ecuador, lo que permite desarrollar un estudio en la provincia de Manabí, tomando una muestra deliberada en el cantón Portoviejo, que concentra el 40% de las cooperativas que operan en la provincia; se utilizó la encuesta como técnica de recolección de datos, y se aplicó a los gerentes, presidentes de los Consejos de Administración y de vigilancia de diez CAC’s; A modo de ...

Planeamiento estratégico de las cajas municipales de ahorro y crédito de la Región Junín

OpenAIRE

Corilla Ruiz, Mariella; Julcarima Iñigo, Gilmar; Meneses Galindez, Carolina; Rodríguez Rivera, Franchesca

2017-01-01

La presente tesis desarrolla un planeamiento estratégico, con el propósito de que las Cajas Municipales de Ahorro y Crédito de la región Junín, se mantengan para el año 2022 como líderes del sector microfinanciero dentro de esta región, mediante la generación de soluciones financieras eficientes y eficaces basadas en incrementar la inclusión y educación financiera, la responsabilidad social y el cuidado del medio ambiente. Así mismo, el presente trabajo tiene por finalidad aume...

Effect of alternating and direct currents on Pseudomonas ...

African Journals Online (AJOL)

The test media were Muller-Hinton agar and eosin methylene blue (EMB) agar. In this research Pseudomonas aeruginosa which was isolated from patients wounds was examined with levels of alternating and direct current (AC and DC) electrical stimulation (1.5V, 3.5V, 5.5V and 10V) to see if these currents could inhibit P.

Implementacion del modelo Lean Service en el proceso de recaudo de la Cooperativa de Ahorro y Crédito Fincomercio ltda

Directory of Open Access Journals (Sweden)

Jonny Gavilán

2016-12-01

Full Text Available El presente trabajo forma parte de la tesis de maestría, para optar al título de Magister en Ingeniería Industrial de la Universidad Distrital Francisco José de Caldas. El cual se basó fundamentalmente en el diseño e implementación del modelo Lean Service para el proceso de recaudo de la Cooperativa de Ahorro y Crédito Fincomercio Ltda. En este marco de referencia, la presente investigación de tipo Descriptivo – Explicativo consistirá en la aplicación de la metodología Lean Service para el mejoramiento del proceso de recaudo de la Cooperativa.

Current and Future Research Directions in Requirements Engineering

Science.gov (United States)

Cheng, Betty H. C.; Atlee, Joanne M.

In this paper, we review current requirements engineering (RE) research and identify future research directions suggested by emerging software needs. First, we overview the state of the art in RE research. The research is considered with respect to technologies developed to address specific requirements tasks, such as elicitation, modeling, and analysis. Such a review enables us to identify mature areas of research, as well as areas that warrant further investigation. Next, we review several strategies for performing and extending RE research results, to help delineate the scope of future research directions. Finally, we highlight what we consider to be the “hot” current and future research topics, which aim to address RE needs for emerging systems of the future.

Análisis de un plan de ahorro energético implementando sistemas fotovoltaicos para los modelos de vivienda propuestos por el gobierno nacional

OpenAIRE

Quinto Ayovi, Marlon Jamil; Cadena Avila, Diego Alberto

2016-01-01

En el siguiente artículo se muestran los diseños de los sistemas fotovoltaicos que se desean implementar a las viviendas modelos propuestas por el gobierno nacional con la finalidad de obtener un ahorro energético a mediano o largo plazo utilizando fuentes de energías renovables como lo es el sol. Se procede a realizar dos escenarios, en el primero escenario se consideran todas las cargas de la vivienda modelo y en el segundo escenario se considera como carga solo a la cocina de inducción, en...

De Cajas de Ahorro a sociedades capitalistas y Fundaciones un nuevo enfoque en la gestión y aplicación de la Obra Social

OpenAIRE

Aranda Ruiviejo, Antonio Carlos; Sotomayor Morales, Eva

2017-01-01

El presente trabajo se ha desarrollado con la finalidad de analizar las estrategias emprendidas por las nuevas Fundaciones surgidas tras el proceso de reestructuración del sector de las Cajas de Ahorro para garantizar la sostenibilidad de la Obra Social que anteriormente venían realizando estas entidades. Para ello se realiza un estudio de carácter descriptivo y explorativo que comprende un horizonte temporal de diez años y en el que se contrastan planteamientos anteriores y posteriores a los...

Projects of electrical energy saving in Costa Rica; Proyectos de ahorro de energia electrica en Costa Rica

Energy Technology Data Exchange (ETDEWEB)

Chinchilla, Henry [Compania Nacional de Luz y Fuerza, S.A., San Jose (Costa Rica)

1999-07-01

Costa Rica, located in Central America, is a highly electrified country, more of the 93.6% of the population, has access to the electricity, and its load curve presents two important demand peaks, one of them near noon and another one at sundown, additionally, the growth of this service is important, reason why it has been oriented to the establishment of actions focussed to the better use of the energy, in special of the electricity. The following notes are intended to show briefly the origin of the actions oriented to the energy saving, identifying the main projects that marked an important track in the national development in this sense, as well as a sample of some of the projects which have permitted to maintain throughout the last decade of this century a permanent attitude on the promotion and education of the saving and handling of the energy demand, specially of electricity, of such a way as to a suitable contribution is achieved towards the industrial competitiveness, human comfort and environmental protection. [Spanish] Costa Rica, ubicado en la America Central, es un pais altamente electrificado, mas del 93.6% de la poblacion, tiene acceso a la electricidad, y su curva de carga presenta dos importantes picos de demanda uno cercano al medio dia y otro al ocultarse el sol, junto a ello el crecimiento este servicio es importante, por lo que se ha abocado a establecer acciones que se orientan al mejor uso de la energia, en especial de la electricidad. En las siguientes notas se trata de mostrar en forma breve el origen de las acciones orientadas al ahorro de energia, identificando los principales proyectos que marcaron una huella importante en el rumbo nacional en este sentido, asi como una muestra de algunos de los proyectos que han permitido mantener a lo largo de la ultima decada de este siglo una permanente actitud de la promocion y ensenanza del ahorro y manejo de la demanda de energia, en especial de la electricidad, de tal forma que se logre con ello

Energy conservation programs of Pemex exploration and production, south region; Programas de ahorro de energia en Pemex exploracion y produccion, region sur

Energy Technology Data Exchange (ETDEWEB)

Gonzalez Milla, Guillermo; Garcia Juarez, Francisco; Alarcon Aleman, Jose Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1999-12-31

The technological developments of energy economizing equipment constitute a powerful tool for the conservation and saving of the electric energy in new or existing installations. Petroleos Mexicanos (PEMEX) Exploration and Production initiated in 1997 a program for energy economizing in the South region, for which the Instituto de Investigaciones Electricas, through its Unit for the Use of Energy, collaborated performing energy assessments in 115 buildings of the above mentioned region. This paper describes the employed methodology to carry on the energy assessment, which consisted in an analysis of each building and different options for energy economizing were presented, which was accompanied with cost-benefit studies. The results obtained show that the air conditioning equipment and lighting represent the most important loads permanently connected, therefore the study was concentrated in these two loads [Espanol] Los desarrollos tecnologicos de equipos ahorradores de energia constituyen una poderosa herramienta para la conservacion y el ahorro de energia electrica en instalaciones nuevas o existentes. Petroleos Mexicanos (PEMEX) Exploracion y Produccion inicio en 1997 un programa para el ahorro de energia en la region sur, para lo cual el Instituto de Investigaciones Electricas, a traves de la Unidad de Uso de Energia, colaboro realizando diagnosticos energeticos en 115 edificios de dicha region. En este documento se describe la metodologia utilizada para realizar el diagnostico energetico, el cual consistio en un analisis de cada edificio y se presentaron diversas opciones para ahorrar energia, lo cual se acompano de estudios de costo-beneficio. Los resultados obtenidos muestran que los equipos de aire acondicionado e iluminacion representan la parte mas importante de las cargas conectadas permanentemente, por lo que el estudio se concentro en estas dos cargas

Energy conservation programs of Pemex exploration and production, south region; Programas de ahorro de energia en Pemex exploracion y produccion, region sur

Energy Technology Data Exchange (ETDEWEB)

Gonzalez Milla, Guillermo; Garcia Juarez, Francisco; Alarcon Aleman, Jose Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

The technological developments of energy economizing equipment constitute a powerful tool for the conservation and saving of the electric energy in new or existing installations. Petroleos Mexicanos (PEMEX) Exploration and Production initiated in 1997 a program for energy economizing in the South region, for which the Instituto de Investigaciones Electricas, through its Unit for the Use of Energy, collaborated performing energy assessments in 115 buildings of the above mentioned region. This paper describes the employed methodology to carry on the energy assessment, which consisted in an analysis of each building and different options for energy economizing were presented, which was accompanied with cost-benefit studies. The results obtained show that the air conditioning equipment and lighting represent the most important loads permanently connected, therefore the study was concentrated in these two loads [Espanol] Los desarrollos tecnologicos de equipos ahorradores de energia constituyen una poderosa herramienta para la conservacion y el ahorro de energia electrica en instalaciones nuevas o existentes. Petroleos Mexicanos (PEMEX) Exploracion y Produccion inicio en 1997 un programa para el ahorro de energia en la region sur, para lo cual el Instituto de Investigaciones Electricas, a traves de la Unidad de Uso de Energia, colaboro realizando diagnosticos energeticos en 115 edificios de dicha region. En este documento se describe la metodologia utilizada para realizar el diagnostico energetico, el cual consistio en un analisis de cada edificio y se presentaron diversas opciones para ahorrar energia, lo cual se acompano de estudios de costo-beneficio. Los resultados obtenidos muestran que los equipos de aire acondicionado e iluminacion representan la parte mas importante de las cargas conectadas permanentemente, por lo que el estudio se concentro en estas dos cargas

Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

DEFF Research Database (Denmark)

Deleebeeck, Lisa; Kammer Hansen, Kent

2015-01-01

collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector......The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...

Wind direction/velocity and current direction/velocity data from current meter casts in a world wide distribution from 1970-12-06 to 1991-10-01 (NODC Accession 9700218)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Wind direction/velocity and current direction/velocity data were collected using current meter casts in a world wide distribution from December 6, 1970 to October 1,...

Soft commutated direct current motor [summary of proposed paper

Energy Technology Data Exchange (ETDEWEB)

Hsu, John S.

1998-10-22

A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.

Transcutaneous Spinal Direct Current Stimulation (tsDCS

Directory of Open Access Journals (Sweden)

Filippo eCogiamanian

2012-07-01

Full Text Available In the past ten years renewed interest has centered on non-invasive transcutaneous weak direct currents applied over the scalp to modulate cortical excitability (brain polarization or transcranial direct current stimulation, tDCS. Extensive literature shows that tDCS induces marked changes in cortical excitability that outlast stimulation.Aiming at developing a new, non invasive, approach to spinal cord neuromodulation we assessed the after-effects of thoracic transcutaneous spinal DC stimulation (tsDCS on somatosensory potentials (SEPs evoked in healthy subjects by posterior tibial nerve (PTN stimulation. Our findings showed that thoracic anodal tsDCS depresses the cervico-medullary PTN-SEP component (P30 without eliciting adverse effects. tsDCS also modulates post-activation H-reflex dynamics. Later works further confirmed that transcutaneous electric fields modulate spinal cord function. Subsequent studies in our laboratory showed that tsDCS modulates the flexion reflex in the human lower limb. Besides influencing the laser evoked potentials, tsDCS increases pain tolerance in healthy subjects. Hence, though the underlying mechanisms remain speculative, tsDCS modulates activity in lemniscal, spinothalamic and segmental motor systems.Here we review currently available experimental evidence that non-invasive spinal cord stimulation influences spinal function in humans and argue that, by focally modulating spinal excitability, tsDCS could provide a novel therapeutic tool complementary to drugs and invasive spinal cord stimulation in managing various pathologic conditions, including pain.

Measurement of direct currents of under 10-10 ampere and of resistances of 1012 Ω for a direct current

International Nuclear Information System (INIS)

Vagner, J.

1965-01-01

Measurement of weak direct currents by Townsend's method using a vibrating condenser electrometer. Development of a current generator giving a pico-ampere independently of the resistance of the circuit used. Development of generators giving currents which may be adjusted continuously and exactly (0.1 to 1 pico-ampere, 1 to 10 pico-amperes, 10 to 100 pico-amperes). Measurement of very high resistances (10 12 Ω) by three different methods. Graphs are made by plotting the value of the resistance against the potential difference applied across it (from 50 milli-volts to 50 volts). Two methods use adjustable current generators and the third is applicable to the measurement of resistances of between 10 7 and 10 13 Ω using a series of condensers ranging from 50 pico-farads to 10 micro-farads. The accuracy of the measurements is between 0. 5 and 1 per cent. (author) [fr

Stimulating thought: a functional MRI study of transcranial direct current stimulation in schizophrenia.

Science.gov (United States)

Orlov, Natasza D; O'Daly, Owen; Tracy, Derek K; Daniju, Yusuf; Hodsoll, John; Valdearenas, Lorena; Rothwell, John; Shergill, Sukhi S

2017-09-01

Individuals with schizophrenia typically suffer a range of cognitive deficits, including prominent deficits in working memory and executive function. These difficulties are strongly predictive of functional outcomes, but there is a paucity of effective therapeutic interventions targeting these deficits. Transcranial direct current stimulation is a novel neuromodulatory technique with emerging evidence of potential pro-cognitive effects; however, there is limited understanding of its mechanism. This was a double-blind randomized sham controlled pilot study of transcranial direct current stimulation on a working memory (n-back) and executive function (Stroop) task in 28 individuals with schizophrenia using functional magnetic resonance imaging. Study participants received 30 min of real or sham transcranial direct current stimulation applied to the left frontal cortex. The 'real' and 'sham' groups did not differ in online working memory task performance, but the transcranial direct current stimulation group demonstrated significant improvement in performance at 24 h post-transcranial direct current stimulation. Transcranial direct current stimulation was associated with increased activation in the medial frontal cortex beneath the anode; showing a positive correlation with consolidated working memory performance 24 h post-stimulation. There was reduced activation in the left cerebellum in the transcranial direct current stimulation group, with no change in the middle frontal gyrus or parietal cortices. Improved performance on the executive function task was associated with reduced activity in the anterior cingulate cortex. Transcranial direct current stimulation modulated functional activation in local task-related regions, and in more distal nodes in the network. Transcranial direct current stimulation offers a potential novel approach to altering frontal cortical activity and exerting pro-cognitive effects in schizophrenia. © The Author (2017). Published by Oxford

Clinical Research with Transcranial Direct Current Stimulation (tDCS): Challenges and Future Directions

Science.gov (United States)

Brunoni, Andre Russowsky; Nitsche, Michael A.; Bolognini, Nadia; Bikson, Marom; Wagner, Tim; Merabet, Lotfi; Edwards, Dylan J.; Valero-Cabre, Antoni; Rotenberg, Alexander; Pascual-Leone, Alvaro; Ferrucci, Roberta; Priori, Alberto; Boggio, Paulo; Fregni, Felipe

2011-01-01

Background Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. In the past ten years, tDCS physiological mechanisms of action have been intensively investigated giving support for the investigation of its applications in clinical neuropsychiatry and rehabilitation. However, new methodological, ethical, and regulatory issues emerge when translating the findings of preclinical and phase I studies into phase II and III clinical studies. The aim of this comprehensive review is to discuss the key challenges of this process and possible methods to address them. Methods We convened a workgroup of researchers in the field to review, discuss and provide updates and key challenges of neuromodulation use for clinical research. Main Findings/Discussion We reviewed several basic and clinical studies in the field and identified potential limitations, taking into account the particularities of the technique. We review and discuss the findings into four topics: (i) mechanisms of action of tDCS, parameters of use and computer-based human brain modeling investigating electric current fields and magnitude induced by tDCS; (ii) methodological aspects related to the clinical research of tDCS as divided according to study phase (i.e., preclinical, phase I, phase II and phase III studies); (iii) ethical and regulatory concerns; (iv) future directions regarding novel approaches, novel devices, and future studies involving tDCS. Finally, we propose some alternative methods to facilitate clinical research on tDCS. PMID:22037126

Combined effects of cerebellar transcranial direct current stimulation and transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke: A pilot, single blind, randomized controlled trial.

Science.gov (United States)

Picelli, Alessandro; Chemello, Elena; Castellazzi, Paola; Filippetti, Mirko; Brugnera, Annalisa; Gandolfi, Marialuisa; Waldner, Andreas; Saltuari, Leopold; Smania, Nicola

2018-01-01

Preliminary evidence showed additional effects of anodal transcranial direct current stimulation over the damaged cerebral hemisphere combined with cathodal transcutaneous spinal direct current stimulation during robot-assisted gait training in chronic stroke patients. This is consistent with the neural organization of locomotion involving cortical and spinal control. The cerebellum is crucial for locomotor control, in particular for avoidance of obstacles, and adaptation to novel conditions during walking. Despite its key role in gait control, to date the effects of transcranial direct current stimulation of the cerebellum have not been investigated on brain stroke patients treated with robot-assisted gait training. To evaluate the effects of cerebellar transcranial direct current stimulation combined with transcutaneous spinal direct current stimulation on robot-assisted gait training in patients with chronic brain stroke. After balanced randomization, 20 chronic stroke patients received ten, 20-minute robot-assisted gait training sessions (five days a week, for two consecutive weeks) combined with central nervous system stimulation. Group 1 underwent on-line cathodal transcranial direct current stimulation over the contralesional cerebellar hemisphere + cathodal transcutaneous spinal direct current stimulation. Group 2 received on-line anodal transcranial direct current stimulation over the damaged cerebral hemisphere + cathodal transcutaneous spinal direct current stimulation. The primary outcome was the 6-minute walk test performed before, after, and at follow-up at 2 and 4 weeks post-treatment. The significant differences in the 6-minute walk test noted between groups at the first post-treatment evaluation (p = 0.041) were not maintained at either the 2-week (P = 0.650) or the 4-week (P = 0.545) follow-up evaluations. Our preliminary findings support the hypothesis that cathodal transcranial direct current stimulation over the contralesional

Evaluation of energy saving in large scale projects in domestic lighting; Evaluacion del ahorro de energia en proyectos de gran escala en alumbrado domestico

Energy Technology Data Exchange (ETDEWEB)

Valera Negrete, Adrian [Comision Federal de Electricidad, Mexico, D.F. (Mexico)

2001-07-01

The present work shows the methodology and the necessary parameters are indicated to evaluate the energy saving and the reduction of power demand obtained, by the large scale projects of substitution of incandescent lamps by compact, circular fluorescent and globe type lamps in the domestic sector. [Spanish] El presente trabajo muestra la metodologia y se indican los parametros necesarios para evaluar el ahorro de energia y reduccion de la demanda de potencia obtenidos, por los proyectos de gran escala de sustitucion de focos incandescentes por lamparas fluorescentes compactas, circulares y tipo globo en el sector domestico.

LANMAS core: Update and current directions

International Nuclear Information System (INIS)

Claborn, J.

1995-01-01

Local Area Network Material Accountability system (LANMAS) core software provides the framework of a material accountability system. It tracks the movement of material throughout a site and generates the required material accountability reports. LANMAS is a net-work- based nuclear material accountability system that runs in a client/server mode. The database of material type and location resides on the server, while the user interface runs on the client. The user interface accesses the data stored on the server via a network. The LANMAS core can be used as the foundation for building required materials control and accountability (MCA) functionality at any site requiring a new MCA system. An individual site will build on the LANMAS core by supplying site-specific software. This paper will provide an update on the current LANMAS development activities and discuss the current direction of the LANMAS project

Current control for magnetized plasma in direct-current plasma-immersion ion implantation

International Nuclear Information System (INIS)

Tang Deli; Chu, Paul K.

2003-01-01

A method to control the ion current in direct-current plasma-immersion ion implantation (PIII) is reported for low-pressure magnetized inductively coupled plasma. The ion current can be conveniently adjusted by applying bias voltage to the conducting grid that separates plasma formation and implantation (ion acceleration) zones without the need to alter the rf input power, gas flux, or other operating conditions. The ion current that diminishes with an increase in grid bias in magnetized plasmas can be varied from 48 to 1 mA by increasing the grid voltage from 0 to 70 V at -50 kV sample bias and 0.5 mTorr hydrogen pressure. High implantation voltage and monoenergetic immersion implantation can now be achieved by controlling the ion current without varying the macroscopic plasma parameters. The experimental results and interpretation of the effects are presented in this letter. This technique is very attractive for PIII of planar samples that require on-the-fly adjustment of the implantation current at high implantation voltage but low substrate temperature. In some applications such as hydrogen PIII-ion cut, it may obviate the need for complicated sample cooling devices that must work at high voltage

Multitarget transcranial direct current stimulation for freezing of gait in Parkinson's disease.

Science.gov (United States)

Dagan, Moria; Herman, Talia; Harrison, Rachel; Zhou, Junhong; Giladi, Nir; Ruffini, Giulio; Manor, Brad; Hausdorff, Jeffrey M

2018-04-01

Recent findings suggest that transcranial direct current stimulation of the primary motor cortex may ameliorate freezing of gait. However, the effects of multitarget simultaneous stimulation of motor and cognitive networks are mostly unknown. The objective of this study was to evaluate the effects of multitarget transcranial direct current stimulation of the primary motor cortex and left dorsolateral prefrontal cortex on freezing of gait and related outcomes. Twenty patients with Parkinson's disease and freezing of gait received 20 minutes of transcranial direct current stimulation on 3 separate visits. Transcranial direct current stimulation targeted the primary motor cortex and left dorsolateral prefrontal cortex simultaneously, primary motor cortex only, or sham stimulation (order randomized and double-blinded assessments). Participants completed a freezing of gait-provoking test, the Timed Up and Go, and the Stroop test before and after each transcranial direct current stimulation session. Performance on the freezing of gait-provoking test (P = 0.010), Timed Up and Go (P = 0.006), and the Stroop test (P = 0.016) improved after simultaneous stimulation of the primary motor cortex and left dorsolateral prefrontal cortex, but not after primary motor cortex only or sham stimulation. Transcranial direct current stimulation designed to simultaneously target motor and cognitive regions apparently induces immediate aftereffects in the brain that translate into reduced freezing of gait and improvements in executive function and mobility. © 2018 International Parkinson and Movement Disorder Society. © 2018 International Parkinson and Movement Disorder Society.

Ahorro infantil: “Chispitas”-Estrategia para combatir la pobreza, Fundación Ayú, Oaxaca, México

Directory of Open Access Journals (Sweden)

Guadalupe Arcos-Medina

2016-01-01

Full Text Available En esta investigación analizamos cómo la estrategia de combate a la pobreza de la Fundación Ayú, influye en el hábito del ahorro de los niños y niñas mixtecos de Oaxaca -los "Chispitas"-, con datos obtenidos de noviembre de 2013 a julio de 2014. Realizamos un taller participativo y entrevistas semiestructuradas, aplicando un cuestionario a 42 niños y niñas de diez años de edad promedio, y antigüedad como ahorradores de entre tres y siete años. El perfil socioeconómico familiar corresponde mayormente a hogares campesinos; las razones para ahorrar son la educación, el futuro y las emergencias, siendo las madres quienes mayor influencia tienen en este hábito. Participar en las cajas visibiliza a los niños y niñas en la localidad y los inicia en la inclusión social y financiera.

Ahorro infantil: “Chispitas”-Estrategia para combatir la pobreza, Fundación Ayú, Oaxaca, México

Directory of Open Access Journals (Sweden)

Guadalupe Arcos-Medina*

2016-02-01

Full Text Available En esta investigación analizamos cómo la estrategia de combate a la pobreza de la Fundación Ayú, influye en el hábito del ahorro de los niños y niñas mixtecos de Oaxaca -los “Chispitas”-, con datos obtenidos de noviembre de 2013 a julio de 2014. Realizamos un taller participativo y entrevistas semiestructuradas, aplicando un cuestionario a 42 niños y niñas de diez años de edad promedio, y antigüedad como ahorradores de entre tres y siete años. El perfil socioeconómico familiar corresponde mayormente a hogares campesinos; las razones para ahorrar son la educación, el futuro y las emergencias, siendo las madres quienes mayor influencia tienen en este hábito. Participar en las cajas visibiliza a los niños y niñas en la localidad y los inicia en la inclusión social y financiera.

Cost-benefit of energy saving in bioclimatic designs; Costo-beneficio del ahorro de energia en los disenos bioclimatios

Energy Technology Data Exchange (ETDEWEB)

Lopez P, J. Manuel A. [Doble dos soluciones de Negocios (Mexico); Morillon G, David; Rdriguez V, Luis [Universidad Autonoma de Mexico (Mexico)

2001-06-01

Tools and criteria for Cost-Benefit Analysis (ACB) of energy saving in bioclimatic designs (DB) are presented, for which a reference project is established. Based on the traditional design of air conditioning of a building and with the support of this one, the estimation of costs and benefits of the same building is made; but with passive systems. The tools used consider related resources such as time and money. Criteria are used such as: Present value (VP), Equivalent Annual Cost (EAC) and the Cost of the conserved Energy (CEC). The costs related to the construction, maintenance and operation of the design are taken into consideration. The differences between the design of reference and the Bioclimatic Design, established from the application of these criteria, allow evaluating the economic margin as far as operation and maintenance. Finally, the cost of the conserved energy of the bioclimatic measures is evaluated as an initiative for energy saving and calculates the present value from them in all of the period of useful life of the bioclimatic design. [Spanish] Se presentan herramientas y criterios para el analisis Costo-Beneficio (ACB) del ahorro de energia en los disenos bioclimaticos (DB), para lo cual se establece un proyecto de referencia. Basado en el diseno tradicional de la climatizacion de un edificio y con apoyo en este, se realiza la estimacion de costos y beneficios del mismo edificio; pero con sistema pasivos. Las herramientas usadas consideran recursos relacionados como son tiempo y dinero. Se usan criterios tales como: Valor Presente (VP), Costo Anual Equivalente (CAE) y el Costo de la Energia conservada (CEC). Se toman en consideracion los costos relacionados con la construccion, mantenimiento y operacion del diseno. Las diferencias entre el diseno de referencia y el Diseno Bioclimatico, establecidas a partir de la aplicacion de estos criterios, permiten evaluar el margen economico en cuanto a la operacion y el mantenimiento. Finalmente, se

Influence of Waveform and Current Direction on Short-Interval Intracortical Facilitation

DEFF Research Database (Denmark)

Delvendahl, Igor; Lindemann, Hannes; Jung, Nikolai H

2014-01-01

-posterior (AP) current direction (AP-AP or PA-PA), whereas current direction was reversed between first and second pulse for half-sine paired-pulse stimulation (PA-AP and AP-PA). RESULTS: Monophasic AP-AP stimulation resulted in stronger early SICF at 1.4 ms relative to late SICF at 2.8 and 4.4 ms, whereas...... monophasic PA-PA stimulation produced SICF of comparable size at all three peaks. With half-sine stimulation the third SICF peak was reduced for PA-AP current orientation compared with AP-PA. CONCLUSION: SICF elicited using monophasic as well as half-sine pulses is affected by current direction at clearly......BACKGROUND: Transcranial magnetic stimulation (TMS) of the human primary motor hand area (M1-HAND) can produce multiple descending volleys in fast-conducting corticospinal neurons, especially so-called indirect waves (I-waves) resulting from trans-synaptic excitation. Facilitatory interaction...

Desarrollo de la capacidad de prevención estratégica en la Cooperativa de Ahorro y Crédito de la Universidad Técnica de Manabí

Directory of Open Access Journals (Sweden)

Ángel Emilio Mendoza Mero

2017-07-01

Full Text Available En este trabajo se presenta un procedimiento que integra cinco pasos para el diagnóstico de la Capacidad de Prevención Estratégica (CAPE a través de la evaluación de los comportamientos prácticos de las 11 variables de la CAPE. La aplicación del procedimiento en la Cooperativa de Ahorro y Crédito de Profesores, Empleados y Trabajadores de la Universidad Técnica de Manabí logró demostrar un bajo desarrollo de la CAPE, limitado por la insuficiente aplicación de la administración de riesgos en el proceso de dirección estratégica. Las mejoras desarrolladas en la cooperativa permitieron aumentar la CAPE así como el diseño e implementación de un programa estratégico de acciones con la reducción de los principales riesgos y un impacto positivo en los indicadores de desempeño financiero de la cooperativa. Se considera un aporte teórico la determinación de la situación problemática a partir de la matriz de relaciones de riesgos.    Palabras clave: capacidad de prevención estratégica, administración de riesgos, cooperativa de ahorro y crédito.

Safety Parameter Considerations of Anodal Transcranial Direct Current Stimulation in Rats

Science.gov (United States)

2017-10-01

Richardson, J.D., Baker, J.M., Rorden, C., 2011. Transcranial direct current stimulation improves naming reaction time in fluent aphasia: a...AFRL-RH-WP-TR-2017-0069 Safety parameter considerations of anodal transcranial Direct Current Stimulation in rats R. Andy McKinley...response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation

OpenAIRE

Kwon, Yong Hyun; Jang, Sung Ho

2012-01-01

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel coun...

Subcortical structures in humans can be facilitated by transcranial direct current stimulation

NARCIS (Netherlands)

Nonnekes, Johan Hendrik; Arrogi, Anass; Munneke, Moniek; van Asseldonk, Edwin H.F.; Oude Nijhuis, Lars; Geurts, Alexander; Weerdesteyn, Vivian

2014-01-01

BACKGROUND: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability via application of a weak direct current. Interestingly, it was demonstrated in cats that tDCS can facilitate subcortical structures as well (Bolzonii et al., J

Co-ordination of directional overcurrent protection with load current for parallel feeders

Energy Technology Data Exchange (ETDEWEB)

Wright, J.W.; Lloyd, G.; Hindle, P.J. [Alstom, Inc., Stafford (United Kingdom). T and D Protection and Control

1999-11-01

Directional phase overcurrent relays are commonly applied at the receiving ends of parallel feeders or transformer feeders. Their purpose is to ensure full discrimination of main or back-up power system overcurrent protection for a fault near the receiving end of one feeder. This paper reviews this type of relay application and highlights load current setting constraints for directional protection. Such constraints have not previously been publicized in well-known text books. A directional relay current setting constraint that is suggested in some text books is based purely on thermal rating considerations for older technology relays. This constraint may not exist with modern numerical relays. In the absence of any apparent constraint, there is a temptation to adopt lower current settings with modern directional relays in relation to reverse load current at the receiving ends of parallel feeders. This paper identifies the danger of adopting very low current settings without any special relay feature to ensure protection security with load current during power system faults. A system incident recorded by numerical relays is also offered to highlight this danger. In cases where there is a need to infringe the identified constraints an implemented and testing relaying technique is proposed.

Levantamiento del proceso de crédito e identificación de eventos de riesgo operativo en la Cooperativa de Ahorro y Crédito OSCUS Ltda.

OpenAIRE

Ibarra Licto, Carmen Jacqueline

2008-01-01

La Cooperativas de ahorro y crédito, como entidades financieras, actúan, se desarrollan y crecen en busca de beneficios mutuos, servicios financieros con rentabilidad y calidad social, y este negocio genérico, que tiene el dinero como vehículo requiere un adecuado manejo y administración de costos operativos, con el objeto de identificar y eliminar costos superfluos, y reducir al óptimo los necesarios, sin dejar de lado que en la actualidad la calidad, innovación y servicio ...

LANMAS core: Update and current directions

International Nuclear Information System (INIS)

Claborn, J.

1994-01-01

Local Area Network Material Accountability System (LANMAS) core software will provide the framework of a material accountability system. LANMAS is a network-based nuclear material accountability system. It tracks the movement of material throughout a site and generates the required reports on material accountability. LANMAS will run in a client/server mode. The database of material type and location will reside on the server, while the user interface runs on the client. The user interface accesses the server via a network. The LANMAS core can be used as the foundation for building required Materials Control and Accountability (MC ampersand A) functionality at any site requiring a new MC ampersand A system. An individual site will build on the LANMAS core by supplying site-specific software. This paper will provide an update on the current LANMAS development activities and discuss the current direction of the LANMAS project

Experimental study of anti-tumor activity of direct current

International Nuclear Information System (INIS)

Ito, Hisao; Hashimoto, Shozo

1989-01-01

The anti-tumor activity of direct current combined with radiation was studied. The experiments were performed with fibrosarcomas (FSA, NFSA) syngenetic to C3H mice. Direct current (0.6mA, 120min) alone was effective to reduce the tumor sizes, but could not cure the tumors. When the direct current therapy (DC therapy) was combined with radiation the DC therapy following radiation was more effective than that before radiation. Using TCD 50 assay, the DC therapy enhanced the effect of a single dose of radiation with the dose-modifying factor of 1.2. However, tumor control rates by the combination therapy were more improved at the smaller doses of radiation than at the larger ones. When the single DC therapy (0.6mA, 120min) was applied immediately after the first radiation of fractionated one the combination therapy still showed the enhanced effect. However, both DC therapy and the radiation therapy were divided in three fractions, and the DC therapy (0.6mA, 40min) was applied after each radiation. Tumor growth retardation by the combination therapy was no different from that by radiation alone. This result suggests that there might be a minimum required dose of coulombs to show the effect of the combination therapy. (author)

Transcranial direct current stimulation enhances propulsion during walking

NARCIS (Netherlands)

van Asseldonk, Edwin H.F.; Jensen, W.; Andersen, O.K.; Akay, M

2014-01-01

Transcranial direct current stimulation (tDCS) has been shown to improve force generation and control in single leg joints in healthy subjects and stroke survivors. However, it is unknown whether these effects also result in improved force production and coordination during walking. Here we

Brainstem tumors: Current management and future directions

Directory of Open Access Journals (Sweden)

Pablo F Recinos

2012-01-01

Full Text Available Tumors arising in the brainstem comprise 10-20% of all pediatric central nervous system (CNS tumors and account for a small percentage in adults. The prognosis for these tumors was considered uniformly poor prior to the era of modern neuroimaging and the location was fraught with disaster being considered a ′no man′s land′ for neurosurgeons. Following the introduction of advanced imaging modalities and neurophysiological monitoring, striking progress has occurred in the management of these lesions. Brainstem tumors are presently classified based on their anatomic location, focality, and histopathology. This article reviews the current classification of brainstem tumors, current management options, and future directions in the treatment for these rare tumors.

Ahorro energético mediante estrategias de iluminación natural optimizadas

Directory of Open Access Journals (Sweden)

Puigdomènech Franquesa, Joan

1986-04-01

Full Text Available Electrical charges in buildings and specially in those of commercial use, can be diminished by means of natural lighting strategies. Taking the climate features of our country into consideration, it is necessary to prevent the inconveniences caused by an en erg y excess in summer, so solar Controls are needed. The only practical way to achieve the suitable balance between thermal and light needs, so as to get a monthly or annual energetic balance optimization, is to operate with the computer. A programme with such characteristics is described here. Its application gives important sarings in non renouvable energy savings.Mediante estrategias de iluminación natural es posible disminuir las cargas eléctricas de los edificios y en especial los de uso comercial. Dadas las características climáticas de nuestro país es necesario prever los inconvenientes de un exceso de energía en verano, para lo cual es preciso disponer de controles solares. Encontrar el correcto equilibrio entre las necesidades térmicas y lumínicas en base a la optimización del balance energético mensual o anual es únicamente factible mediante el uso del ordenador. Un programa que responde a estas características es descrito en el presente trabajo, obteniéndose con su aplicación importantes ahorros en el consumo de energías no renovables.

Transcranial direct current stimulation as a treatment for auditory hallucinations.

Directory of Open Access Journals (Sweden)

Sanne eKoops

2015-03-01

Full Text Available Auditory hallucinations (AH are a symptom of several psychiatric disorders, such as schizophrenia. In a significant minority of patients, AH are resistant to antipsychotic medication. Alternative treatment options for this medication-resistant group are scarce and most of them focus on coping with the hallucinations. Finding an alternative treatment that can diminish AH is of great importance.Transcranial direct current stimulation (tDCS is a safe and non-invasive technique that is able to directly influence cortical excitability through the application of very low electric currents. A 1-2 mA direct current is applied between two surface electrodes, one serving as the anode and the other as the cathode. Cortical excitability is increased in the vicinity of the anode and reduced near the cathode. The technique, which has only a few transient side effects and is cheap and portable, is increasingly explored as a treatment for neurological and psychiatric symptoms. It has shown efficacy on symptoms of depression, bipolar disorder, schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy and stroke. However, the application of tDCS as a treatment for AH is relatively new. This article provides an overview of the current knowledge in this field and provides guidelines for future research.

[The risk of direct current countershock].

Science.gov (United States)

Gajek, J; Zyśko, D

2001-07-01

Direct current cardioversion (DCC) is a procedure commonly used to restore the sinus rhythm in patients with supraventricular and ventricular arrhythmias. Its safety, regarding the use of electric current, is still a matter of controversy and debate. The patients with atrial fibrillation/flutter, supraventricular or ventricular tachycardia represent a broad spectrum of clinical conditions and it is difficult to draw the conclusions. The high success rate of DCC in restoring the sinus rhythm, may be partly responsible for enhancing and revealing proarrhythmic properties of antiarrhythmic drugs. The deaths described as a complications of DCC were mainly due to the proarrhythmia and less common to the progression of the pathologic process. The embolic, arrhythmic and anesthetic complications of DCC can be prevented if the known recommendations of performing the DCC are followed. The authors review critically the literature data about the complications of the procedure and come to the conclusion of safety of DCC.

Project of energy saving in compressed air; Proyecto de ahorro de energia en aire comprimido

Energy Technology Data Exchange (ETDEWEB)

Automatizacion, Productividad y Calidad S.A. de C.V. Puebla, (Mexico)

2005-07-01

The objective of this project is to reduce the operation costs by means of the energy saving through the use of the compressed air system. For this purpose the solenoid valves controlled per time and the manually acted valves of sphere must be replaced by pneumatic purges that remove from the system the condensed humidity without discharging air and which act automatically when the water reaches the level of unloading in its deposit. The pressure level is the reduction of the operation rank of pressure in the compressors, satisfying the operation requirements of the process equipment. [Spanish] El objetivo de este proyecto es reducir el costo de operacion mediante el ahorro de energia en la utilizacion del sistema de aire comprimido. Para ello se tienen que remplazar las valvulas solenoides controladas por tiempo y valvulas de esfera actuadas manualmente por purgas neumaticas que remueven del sistema la humedad condensada sin descargar aire y que actuan en forma automatica al alcanzar el agua el nivel de descarga en su deposito. El nivel de presion es la reduccion del rango de operacion de presion de los compresores, satisfaciendo los requerimientos de operacion de los equipos de proceso.

Directed Motivational Currents: Using vision to create effective motivational pathways

Directory of Open Access Journals (Sweden)

Christine Muir

2013-10-01

Full Text Available Vision, that is, the mental representation of the sensory experience of a future goal state (involving imagination and imagery, is currently at the forefront of motivational innovation, and in recent years it has been seen increasingly more often in the motivational tool kit of practicing language teachers. Theories such as Dörnyei’s L2 motivational self system have explored the power that creating effective visions can harness (see, e.g., Dörnyei & Kubanyiova, 2014 and when viewed in conjunction with other current research avenues, such as future time perspective and dynamic systems theory, vision offers exciting potential. A Directed Motivational Current is a new motivational construct that we suggest is capable of integrating many current theoretical strands with vision: It can be described as a motivational drive which energises long-term, sustained behaviour (such as language learning, and through placing vision and goals as critical central components within this construct, it offers real and practical motivational potential. In this conceptual paper, we first discuss current understandings of vision and of Directed Motivational Currents, and then analyse how they may be optimally integrated and employed to create effective motivational pathways in language learning environments.

Analysis of electromagnetic field of direct action solenoid valve with current changing

International Nuclear Information System (INIS)

Liu Qianfeng; Bo Hanliang; Qin Benke

2009-01-01

Control rod hydraulic drive mechanism(CRHDM) is a newly invented patent of Institute of Nuclear and New Energy Technology of Tsinghua University. The direct action solenoid valve is the key part of this technology, so the performance of the solenoid valve directly affects the function of the CRHDM. With the current and the air gap changing,the electromagnetic field of the direct action solenoid valve was analyzed using the ANSYS software,which was validated by the experiment. The result shows that the electromagnetic force of the solenoid valve increases with the current increasing or the gap between the two armatures decreasing. Further more, the working current was confirmed. (authors)

Potential of bioclimatic architecture for energy saving in buildings; Potencial de la arquitectura bioclimatica para ahorro de energia en edificios

Energy Technology Data Exchange (ETDEWEB)

Garcia Chavez, Jose Roberto [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D. F. (Mexico)

1994-12-31

The design and construction of current buildings has been characterized, most of all, in the last 30 years, for the lack of consideration in the design process of aspects that nowadays represent a fundamental importance. These aspects are related to energy conservation and environmental protection, with man as the main center of attention for the optimum satisfaction of its physiological as well as psychological needs. In this paper are presented the causes for the lack of consideration of the mentioned aspects and guidelines to follow are set forth for their integration in the design process. Also the architecture potential with a bioclimatic approach is analyzed, for energy saving in buildings. [Espanol] El diseno y construccion de edificios contemporaneos se ha caracterizado, sobre todo en los ultimos treinta anos, por la falta de consideracion en el proceso de diseno, de aspectos que hoy en dia revisten una importancia primordial. Estos aspectos se relacionan con la preservacion de la energia y del medio ambiente, teniendo al hombre como principal centro de atencion, para la satisfaccion optima de sus necesidades, tanto fisiologicas como psicologicas. En este trabajo, se presentan las causas de la falta de consideracion de los aspectos antes citados y se plantean las pautas a seguir para su integracion en el proceso de diseno. Asi mismo, se analiza el potencial de la arquitectura con un enfoque bioclimatico, para ahorro de energia en los edificios.

Multiday Transcranial Direct Current Stimulation Causes Clinically Insignificant Changes in Childhood Dystonia: A Pilot Study.

Science.gov (United States)

Bhanpuri, Nasir H; Bertucco, Matteo; Young, Scott J; Lee, Annie A; Sanger, Terence D

2015-10-01

Abnormal motor cortex activity is common in dystonia. Cathodal transcranial direct current stimulation may alter cortical activity by decreasing excitability while anodal stimulation may increase motor learning. Previous results showed that a single session of cathodal transcranial direct current stimulation can improve symptoms in childhood dystonia. Here we performed a 5-day, sham-controlled, double-blind, crossover study, where we measured tracking and muscle overflow in a myocontrol-based task. We applied cathodal and anodal transcranial direct current stimulation (2 mA, 9 minutes per day). For cathodal transcranial direct current stimulation (7 participants), 3 subjects showed improvements whereas 2 showed worsening in overflow or tracking error. The effect size was small (about 1% of maximum voluntary contraction) and not clinically meaningful. For anodal transcranial direct current stimulation (6 participants), none showed improvement, whereas 5 showed worsening. Thus, multiday cathodal transcranial direct current stimulation reduced symptoms in some children but not to a clinically meaningful extent, whereas anodal transcranial direct current stimulation worsened symptoms. Our results do not support transcranial direct current stimulation as clinically viable for treating childhood dystonia. © The Author(s) 2015.

El capital social y su tratamiento en las entidades en las entidades de ahorro y crédito popular sobre la base de la normativa contable internacional

Directory of Open Access Journals (Sweden)

Luis Carlos Gámez Adame

2013-03-01

Full Text Available Las Entidades de Ahorro y Crédito Popular (Cooperativas constituyen un segmento importante dentro de los servicios financieros que se prestan en diferentes países y que han tenido un desarrollo vertiginoso al satisfacer demandas y necesidades de numerosas masas poblacionales.Se presentan algunas consideraciones asociadas al tratamiento del capital social en estas entidades sobre la base de la normatividad contable internacional vigente y donde a criterio de los autores existen una serie de incongruencias a las que hay que darles solución.

Direct calculation of current drive efficiency in FISIC code

International Nuclear Information System (INIS)

Wright, J.C.; Phillips, C.K.; Bonoli, P.T.

1996-01-01

Two-dimensional RF modeling codes use a parameterization (1) of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform quasi-linear diffusion coefficient and requires a priori knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by the full wave code, FISIC (2). Current profiles are calculated using the adjoint formulation (3). Comparisons between the two formulations are presented. copyright 1996 American Institute of Physics

The use of reflecting paints on building`s roofs for energy saving; Uso de pinturas reflejantes en los techos de las edificaciones para el ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Valera Negrete, Jose Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Comision Federal de Electricidad, Mexico, D. F. (Mexico); Sanchez Soto, Ramon [Facultad de Ingenieria, Departamento de Termoenergia de la UNAM, Mexico, D. F. (Mexico)

1998-12-31

This paper shows the effects of the use of reflecting paints in different colors on the buildings roofs and the results in energy saving obtained in a field test carried on in Monterrey, Nuevo Leon State of Mexico using aluminum paint. [Espanol] El presente trabajo muestra los efectos del uso de pinturas reflejantes de diferentes colores en los techos de edificaciones, y los resultados de ahorro de energia electrica obtenidos en una prueba de campo efectuada en Monterrey, Nuevo Leon, Mexico, utilizando pintura de aluminio.

The use of reflecting paints on building`s roofs for energy saving; Uso de pinturas reflejantes en los techos de las edificaciones para el ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Valera Negrete, Jose Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Comision Federal de Electricidad, Mexico, D. F. (Mexico); Sanchez Soto, Ramon [Facultad de Ingenieria, Departamento de Termoenergia de la UNAM, Mexico, D. F. (Mexico)

1999-12-31

This paper shows the effects of the use of reflecting paints in different colors on the buildings roofs and the results in energy saving obtained in a field test carried on in Monterrey, Nuevo Leon State of Mexico using aluminum paint. [Espanol] El presente trabajo muestra los efectos del uso de pinturas reflejantes de diferentes colores en los techos de edificaciones, y los resultados de ahorro de energia electrica obtenidos en una prueba de campo efectuada en Monterrey, Nuevo Leon, Mexico, utilizando pintura de aluminio.

Results in energy saving obtained with the application of speed variator in fossil power stations; Resultados de ahorro de energia obtenidos con la aplicacion de variadores de velocidad en centrales termoelectricas

Energy Technology Data Exchange (ETDEWEB)

Merlos Rueda, Rosa Maria [Programa de Ahorro de Energia del Sector Electrico (PAESE), Mexico, D. F. (Mexico)

1999-07-01

The project of installation of speed variator in fossil power stations (CT's) of Comision Federal de Electricidad (CFE), as an energy saving measure, is a pilot project that began with the support of the Subdivision de Generacion, and promoted by the Energy Saving Program of the Electric Sector (PAESE), with the putting in operation of an equipment in the condensate pump of the Punta Prieta II C. T. U3. The energy saving observed was substantial, fluctuating between the 19.4% at high loads (at 90% load) and the 71.1% at low loads (at 40% load) of the generating unit. With these results, it was decided to extend the scope of the project with the installation of 6 more equipment for equal number of fossil power stations, located in 4 of the 5 Regions of Generation. The fossil power stations, selected for this stage of the project were: C. T. Felipe Carrillo Puerto U1, C.T. Lerma U4, C.T. Salamanca U1, C.T. Monterrey U6, C.T. Francisco Villa U3 and the C.T. Punta Prieta II-U1. The equipment was in operation during the first quarter of 1998, and the first results indicate an energy savings average per equipment, between 39% and 52%. The recovery of the investment fluctuates between the 48.4% and the 87.6% in less than two years of operation, with which a maximum period of recovery of 3 years is expected. The estimated potential of energy saving, considering the application of these devices in condensate pumps, feedwater pumps (where no speed variator is installed) forced draft fans, induced draft fans and gas recirculation fans, as well as circulation water pumps, of the existing Generating Power stations, ascends to an annual total of 830,000, which represents an approximate 9.4% of the National consumption of self services. [Spanish] El proyecto de instalacion de variadores de velocidad en Centrales Termoelectricas (CT's) de la Comision Federal de Electricidad (CFE), como medida de ahorro de energia, es un proyecto piloto que se inicio con el apoyo de la

The control of the upstream movement of fish with pulsated direct current

Science.gov (United States)

McLain, Alberton L.

1957-01-01

Alternating-current electromechanical devices installed in the mouths of streams have proved effective in stopping the spawning migrations of the parasitic sea lamprey (Petromyzon marinus) which has seriously damaged Great Lakes fisheries. In a few streams, excessive mortality has occurred to other fish at the alternating-current barriers. A direct-current unit was developed in an attempt to reduce this mortality. This direct-current “diversion device” consists of a row of suspended negative electrodes which begins at the end of a trap wing and extends across the river at a downstream angle of 45° and a series of pipes (positive electrodes) driven into the stream bank. A second array, consisting of horizontal pipes installed downstream and parallel to the suspended electrodes and connected to a series of rods driven into the bank near the positive electrodes, controls the electrical field and dissipates the collecting influence of the positive side of the circuit. The electrical field is established from the end of the trap wing to the opposite bank. Fish are diverted away from the negative electrodes and toward the bank near which the trap is located. The array is activiated by pulsated direct current of essentially square wave shape with pulses at a duty cycle of 0.66 and a repetition rate of 3 per second. Direct-current diversion devices were operated in conjunction with alternating-current barriers during 1956 in the Chocolay River, Marquette County, and the Silver River, Baraga County, Michigan.

Transcranial direct current stimulation for motor recovery of upper limb function after stroke.

Science.gov (United States)

Lüdemann-Podubecká, Jitka; Bösl, Kathrin; Rothhardt, Sandra; Verheyden, Geert; Nowak, Dennis Alexander

2014-11-01

Changes in neural processing after stroke have been postulated to impede recovery from stroke. Transcranial direct current stimulation has the potential to alter cortico-spinal excitability and thereby might be beneficial in stroke recovery. We review the pertinent literature prior to 30/09/2013 on transcranial direct current stimulation in promoting motor recovery of the affected upper limb after stroke. We found overall 23 trials (they included 523 participants). All stimulation protocols pride on interhemispheric imbalance model. In a comparative approach, methodology and effectiveness of (a) facilitation of the affected hemisphere, (b) inhibition of the unaffected hemisphere and (c) combined application of transcranial direct current stimulation over the affected and unaffected hemispheres to treat impaired hand function after stroke are presented. Transcranial direct current stimulation is associated with improvement of the affected upper limb after stroke, but current evidence does not support its routine use. Copyright © 2014 Elsevier Ltd. All rights reserved.

Current directions in radiopharmaceutical research

Energy Technology Data Exchange (ETDEWEB)

Mather, S J [Department of Nuclear Medicine, St. Bartholomew` s Hospital, London (United Kingdom)

1998-08-01

Much of current radiopharmaceutical research is directed towards the development of receptor-binding tracers which are targeted towards biochemical processes. These may be extra or intracellular in nature and hold promise for an imaging approach to tissue characterisation in-vivo. Many of these products are based on proteins which range in size from large monoclonal antibodies to small neuropeptides and share a radiolabelling chemistry based on the use of bifunctional chelating agents. Although developed initially for use with indium-111, considerations of cost and isotope availability have continued to direct the efforts of many researchers towards the use of technetium-99m. While polypeptide-based radiopharmaceuticals may be useful for imaging peripheral cell-surface receptors, access to sites of interest within the cell, or in the brain, requires the development of small lipophilic molecules with retained ability to interact with intracellular targets. The design and synthesis of these compounds presents a particular challenge to the radiopharmaceutical chemist which is being met through either a pendant or integrated approach to the use of technetium coordination with particular emphasis on technetium (v) cores. Progress continues to be made in the application of targeted radionuclide therapy particularly in the development of radiopharmaceuticals for the treatment of malignant bone disease. methods for labelling antibodies with a great variety of cytotoxic radionuclides have now been refined and their use for radioimmunotherapy in the treatment of haematological malignancies shows great promise. The major medical areas for application of these new radiopharmaceuticals will be in oncology, neurology and inflammation but the increasingly difficult regulatory climate in which drug development and health-care now operate will make it essential for researchers to direct their products toward specific clinical problems as well as biological targets. (author) 36 refs

Current directions in radiopharmaceutical research

International Nuclear Information System (INIS)

Mather, S.J.

1998-01-01

Much of current radiopharmaceutical research is directed towards the development of receptor-binding tracers which are targeted towards biochemical processes. These may be extra or intracellular in nature and hold promise for an imaging approach to tissue characterisation in-vivo. Many of these products are based on proteins which range in size from large monoclonal antibodies to small neuropeptides and share a radiolabelling chemistry based on the use of bifunctional chelating agents. Although developed initially for use with indium-111, considerations of cost and isotope availability have continued to direct the efforts of many researchers towards the use of technetium-99m. While polypeptide-based radiopharmaceuticals may be useful for imaging peripheral cell-surface receptors, access to sites of interest within the cell, or in the brain, requires the development of small lipophilic molecules with retained ability to interact with intracellular targets. The design and synthesis of these compounds presents a particular challenge to the radiopharmaceutical chemist which is being met through either a pendant or integrated approach to the use of technetium coordination with particular emphasis on technetium (v) cores. Progress continues to be made in the application of targeted radionuclide therapy particularly in the development of radiopharmaceuticals for the treatment of malignant bone disease. methods for labelling antibodies with a great variety of cytotoxic radionuclides have now been refined and their use for radioimmunotherapy in the treatment of haematological malignancies shows great promise. The major medical areas for application of these new radiopharmaceuticals will be in oncology, neurology and inflammation but the increasingly difficult regulatory climate in which drug development and health-care now operate will make it essential for researchers to direct their products toward specific clinical problems as well as biological targets. (author)

Current Direct Neutrino Mass Experiments

Directory of Open Access Journals (Sweden)

G. Drexlin

2013-01-01

Full Text Available In this contribution, we review the status and perspectives of direct neutrino mass experiments, which investigate the kinematics of β-decays of specific isotopes (3H, 187Re, 163Ho to derive model-independent information on the averaged electron (antineutrino mass. After discussing the kinematics of β-decay and the determination of the neutrino mass, we give a brief overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and Troitsk experiments for 3H, cryobolometers for 187Re. We then describe the Karlsruhe Tritium Neutrino (KATRIN experiment currently under construction at Karlsruhe Institute of Technology, which will use the MAC-E-Filter principle to push the sensitivity down to a value of 200 meV (90% C.L.. To do so, many technological challenges have to be solved related to source intensity and stability, as well as precision energy analysis and low background rate close to the kinematic endpoint of tritium β-decay at 18.6 keV. We then review new approaches such as the MARE, ECHO, and Project8 experiments, which offer the promise to perform an independent measurement of the neutrino mass in the sub-eV region. Altogether, the novel methods developed in direct neutrino mass experiments will provide vital information on the absolute mass scale of neutrinos.

Direct-current-like Phase Space Manipulation Using Chirped Alternating Current Fields

International Nuclear Information System (INIS)

Schmit, P.F.; Fisch, N.J.

2010-01-01

Waves in plasmas can accelerate particles that are resonant with the wave. A dc electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. Whereas wave-particle acceleration mechanisms have been widely discussed in the literature, this work discusses the direct analogy between wave acceleration and dc field acceleration in a particular parameter regime explored in previous works. Apart from the academic interest of this correspondence, there may be practical advantages in using waves to mimic dc electric fields, for example, in driving plasma current with high efficiency.

Obesity pharmacotherapy: current perspectives and future directions.

Science.gov (United States)

Misra, Monika

2013-02-01

The rising tide of obesity and its related disorders is one of the most pressing health concerns worldwide, yet existing medicines to combat the problem are disappointingly limited in number and effectiveness. Recent advances in mechanistic insights into the neuroendocrine regulation of body weight have revealed an expanding list of molecular targets for novel, rationally designed antiobesity pharmaceutical agents. Antiobesity drugs act via any of four mechanisms: 1) decreasing energy intake, 2) increasing energy expenditure or modulating lipid metabolism, 3) modulating fat stores or adipocyte differentiation, and 4) mimicking caloric restriction. Various novel drug candidates and targets directed against obesity are currently being explored. A few of them are also in the later phases of clinical trials. This review discusses the development of novel antiobesity drugs based on current understanding of energy homeostasis.

Optimization of focality and direction in dense electrode array transcranial direct current stimulation (tDCS)

Science.gov (United States)

Guler, Seyhmus; Dannhauer, Moritz; Erem, Burak; Macleod, Rob; Tucker, Don; Turovets, Sergei; Luu, Phan; Erdogmus, Deniz; Brooks, Dana H.

2016-06-01

Objective. Transcranial direct current stimulation (tDCS) aims to alter brain function non-invasively via electrodes placed on the scalp. Conventional tDCS uses two relatively large patch electrodes to deliver electrical current to the brain region of interest (ROI). Recent studies have shown that using dense arrays containing up to 512 smaller electrodes may increase the precision of targeting ROIs. However, this creates a need for methods to determine effective and safe stimulus patterns as the number of degrees of freedom is much higher with such arrays. Several approaches to this problem have appeared in the literature. In this paper, we describe a new method for calculating optimal electrode stimulus patterns for targeted and directional modulation in dense array tDCS which differs in some important aspects with methods reported to date. Approach. We optimize stimulus pattern of dense arrays with fixed electrode placement to maximize the current density in a particular direction in the ROI. We impose a flexible set of safety constraints on the current power in the brain, individual electrode currents, and total injected current, to protect subject safety. The proposed optimization problem is convex and thus efficiently solved using existing optimization software to find unique and globally optimal electrode stimulus patterns. Main results. Solutions for four anatomical ROIs based on a realistic head model are shown as exemplary results. To illustrate the differences between our approach and previously introduced methods, we compare our method with two of the other leading methods in the literature. We also report on extensive simulations that show the effect of the values chosen for each proposed safety constraint bound on the optimized stimulus patterns. Significance. The proposed optimization approach employs volume based ROIs, easily adapts to different sets of safety constraints, and takes negligible time to compute. An in-depth comparison study gives

Outcomes in spasticity after repetitive transcranial magnetic and transcranial direct current stimulations

OpenAIRE

Gunduz, Aysegul; Kumru, Hatice; Pascual-Leone, Alvaro

2014-01-01

Non-invasive brain stimulations mainly consist of repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Repetitive transcranial magnetic stimulation exhibits satisfactory outcomes in improving multiple sclerosis, stroke, spinal cord injury and cerebral palsy-induced spasticity. By contrast, transcranial direct current stimulation has only been studied in post-stroke spasticity. To better validate the efficacy of non-invasive brain stimulations in improving ...

Technology-based suicide prevention: current applications and future directions.

Science.gov (United States)

Luxton, David D; June, Jennifer D; Kinn, Julie T

2011-01-01

This review reports on current and emerging technologies for suicide prevention. Technology-based programs discussed include interactive educational and social networking Web sites, e-mail outreach, and programs that use mobile devices and texting. We describe innovative applications such as virtual worlds, gaming, and text analysis that are currently being developed and applied to suicide prevention and outreach programs. We also discuss the benefits and limitations of technology-based applications and discuss future directions for their use.

Method for exciting inductive-resistive loads with high and controllable direct current

International Nuclear Information System (INIS)

Hill, H.M. Jr.

1976-01-01

The apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator are described. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100 percent duty factor amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity. 4 Claims, 18 Drawing Figures

Experiences on energy saving in Comision Federal Electricidad (CFE) buildings; Experiencias de ahorro de energia en edificios de la Comision Federal de Electricidad (CFE)

Energy Technology Data Exchange (ETDEWEB)

Alvarez Velasco, Jorge E [Comision Federal de Electricidad (CFE) (Mexico)

2005-07-01

This document describes the developed saving projects in buildings and generating power stations in 2004 by the Comision Federal de Electricidad (CFE). The projects considered are: buildings of the oficinas nacionales, Divisions of distribution office buildings, office buildings of production regions, construction deputy manager's office building, buildings of transmission and transformation, generating power stations, investments and savings of the projects in oficinas nacionales, divisions of distribution and construction subdivision buildings. From these projects the ones concluded in the 2004 were: Distribution Divisions, Gulf-Center Division, Center-West Distribution Division. The developing projects of 2005: oficinas nacionales, distribution divisions, Construction Subdivision, Generating Power Stations, Transmission Areas and office buildings. And finally, the projects concluded in the 2005 are the distribution divisions, the construction subdivision, the generating power stations, the office buildings, the minisplit units and their advantages with respect to the air conditioning window units. [Spanish] Este documento describe los proyectos de ahorro desarrollados en inmuebles y centrales generadoras en el ano 2004 por la Comision Federal de Electricidad (CFE), los proyectos tratados son: inmuebles de oficinas nacionales, inmuebles de divisiones de distribucion, inmuebles de regiones de produccion, inmuebles de la subdireccion de construccion, inmuebles de transmision y transformacion, centrales generadoras, inversiones y ahorros de los proyectos en inmuebles de oficinas nacionales y divisiones de distribucion y subdireccion de construccion. De dichos proyectos se tiene que los proyectos concluidos en el 2004 fueron: Divisiones de Distribucion, Division Golfo Centro, Division de Distribucion Centro Occidente. Los proyectos en desarrollo del 2005: oficinas nacionales, divisiones de distribucion, Subdireccion de Construccion, Centrales Generadoras, Areas de

Experiences on energy saving in Comision Federal Electricidad (CFE) buildings; Experiencias de ahorro de energia en edificios de la Comision Federal de Electricidad (CFE)

Energy Technology Data Exchange (ETDEWEB)

Alvarez Velasco, Jorge E. [Comision Federal de Electricidad (CFE) (Mexico)

2005-07-01

This document describes the developed saving projects in buildings and generating power stations in 2004 by the Comision Federal de Electricidad (CFE). The projects considered are: buildings of the oficinas nacionales, Divisions of distribution office buildings, office buildings of production regions, construction deputy manager's office building, buildings of transmission and transformation, generating power stations, investments and savings of the projects in oficinas nacionales, divisions of distribution and construction subdivision buildings. From these projects the ones concluded in the 2004 were: Distribution Divisions, Gulf-Center Division, Center-West Distribution Division. The developing projects of 2005: oficinas nacionales, distribution divisions, Construction Subdivision, Generating Power Stations, Transmission Areas and office buildings. And finally, the projects concluded in the 2005 are the distribution divisions, the construction subdivision, the generating power stations, the office buildings, the minisplit units and their advantages with respect to the air conditioning window units. [Spanish] Este documento describe los proyectos de ahorro desarrollados en inmuebles y centrales generadoras en el ano 2004 por la Comision Federal de Electricidad (CFE), los proyectos tratados son: inmuebles de oficinas nacionales, inmuebles de divisiones de distribucion, inmuebles de regiones de produccion, inmuebles de la subdireccion de construccion, inmuebles de transmision y transformacion, centrales generadoras, inversiones y ahorros de los proyectos en inmuebles de oficinas nacionales y divisiones de distribucion y subdireccion de construccion. De dichos proyectos se tiene que los proyectos concluidos en el 2004 fueron: Divisiones de Distribucion, Division Golfo Centro, Division de Distribucion Centro Occidente. Los proyectos en desarrollo del 2005: oficinas nacionales, divisiones de distribucion, Subdireccion de Construccion, Centrales Generadoras, Areas

Helicopter Rotor Noise Prediction: Background, Current Status, and Future Direction

Science.gov (United States)

Brentner, Kenneth S.

1997-01-01

Helicopter noise prediction is increasingly important. The purpose of this viewgraph presentation is to: 1) Put into perspective the recent progress; 2) Outline current prediction capabilities; 3) Forecast direction of future prediction research; 4) Identify rotorcraft noise prediction needs. The presentation includes an historical perspective, a description of governing equations, and the current status of source noise prediction.

Current direction, wind direction, temperature, and salinity data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 01 February 1981 - 01 February 1981 (NODC Accession 8100516)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, temperature, wind direction, and salinity data were collected using moored current meter casts in the Gulf of Mexico from February 1, 1981 to...

Impact of transcranial direct current stimulation (tDCS) on neuronal functions

NARCIS (Netherlands)

Das, S. (Suman); P.J. Holland (Peter); M.A. Frens (Maarten); O. Donchin (Opher)

2016-01-01

textabstractTranscranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, modulates neuronal excitability by the application of a small electrical current. The low cost and ease of the technique has driven interest in potential clinical applications. However, outcomes

Onsite-effects of dual-hemisphere versus conventional single-hemisphere transcranial direct current stimulation: A functional MRI study.

Science.gov (United States)

Kwon, Yong Hyun; Jang, Sung Ho

2012-08-25

We performed functional MRI examinations in six right-handed healthy subjects. During functional MRI scanning, transcranial direct current stimulation was delivered with the anode over the right primary sensorimotor cortex and the cathode over the left primary sensorimotor cortex using dual-hemispheric transcranial direct current stimulation. This was compared to a cathode over the left supraorbital area using conventional single-hemispheric transcranial direct current stimulation. Voxel counts and blood oxygenation level-dependent signal intensities in the right primary sensorimotor cortex regions were estimated and compared between the two transcranial direct current stimulation conditions. Our results showed that dual-hemispheric transcranial direct current stimulation induced greater cortical activities than single-hemispheric transcranial direct current stimulation. These findings suggest that dual-hemispheric transcranial direct current stimulation may provide more effective cortical stimulation than single-hemispheric transcranial direct current stimulation.

Analysis of critical thinking ability in direct current electrical problems solving

Science.gov (United States)

Hartono; Sunarno, Widha; Sarwanto; Arya Nugraha, Dewanta

2017-11-01

This study concern on analyzing the ability of students in critical thinking skills on the subject matter of direct current electricity. Samples were taken using purposive random sampling consisted of 32 students of grade XI, Multimedia 1, SMK Negeri 3 Surakarta in academic year 2016/2017. This study used descriptive quantitative method. The data were collected using tests and interviews regarding the subject matter of direct current electricity. Based on the results, students are getting some difficulties in solving problem in indicator 4. The average of students’ correct answer is 62.8%.

Revision of the Euratom basic safety standards directive-current status

International Nuclear Information System (INIS)

Mundig, S.

2011-01-01

The European Commission is currently developing a revised Euratom Basic Safety Standards (BSS) Directive covering two major objectives: the consolidation of existing Euratom Radiation Protection legislation and the revision of the Euratom BSS. The consolidation will merge the following five Directives into one single Directive: the BSS Directive, the Medical Exposures Directive, the Public Information Directive, the Outside Workers Directive and the Directive on the Control of high-activity sealed radioactive sources and orphan sources. The revision of the Euratom BSS will take account of the latest recommendations by the International Commission on Radiological Protection and shall improve clarity of the requirements where appropriate. It is planned to introduce more binding requirements on natural radiation sources, on criteria for exemption and clearance, and on the cooperation between Member States for emergency planning and response. The provisions for regulatory control of planned exposure situations foresee a graded approach commensurate to the magnitude and likelihood of exposures from a practice. Finally, the new BSS shall take account of recent scientific developments. One additional goal is to achieve greater harmonisation between the Euratom BSS and the international BSS. While the requirements on the protection of workers, apprentices and students remain nearly unchanged, the revised BSS will clarify the roles and responsibilities of services and experts involved in technical and practical aspects of radiation protection, such as the occupational health services, the dosimetry services, the radiation protection expert and the medical physics expert. The requirements in the BSS on individual monitoring of category A workers remain unchanged, but the existing guidance on individual monitoring was revised and updated-the technical recommendations for monitoring individuals occupationally exposed to external radiation are published by the European

Novel methods to optimize the effects of transcranial direct current stimulation: a systematic review of transcranial direct current stimulation patents.

Science.gov (United States)

Malavera, Alejandra; Vasquez, Alejandra; Fregni, Felipe

2015-01-01

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that has been extensively studied. While there have been initial positive results in some clinical trials, there is still variability in tDCS results. The aim of this article is to review and discuss patents assessing novel methods to optimize the use of tDCS. A systematic review was performed using Google patents database with tDCS as the main technique, with patents filling date between 2010 and 2015. Twenty-two patents met our inclusion criteria. These patents attempt to address current tDCS limitations. Only a few of them have been investigated in clinical trials (i.e., high-definition tDCS), and indeed most of them have not been tested before in human trials. Further clinical testing is required to assess which patents are more likely to optimize the effects of tDCS. We discuss the potential optimization of tDCS based on these patents and the current experience with standard tDCS.

The morphological and molecular changes of brain cells exposed to direct current electric field stimulation.

Science.gov (United States)

Pelletier, Simon J; Lagacé, Marie; St-Amour, Isabelle; Arsenault, Dany; Cisbani, Giulia; Chabrat, Audrey; Fecteau, Shirley; Lévesque, Martin; Cicchetti, Francesca

2014-12-07

The application of low-intensity direct current electric fields has been experimentally used in the clinic to treat a number of brain disorders, predominantly using transcranial direct current stimulation approaches. However, the cellular and molecular changes induced by such treatment remain largely unknown. Here, we tested various intensities of direct current electric fields (0, 25, 50, and 100V/m) in a well-controlled in vitro environment in order to investigate the responses of neurons, microglia, and astrocytes to this type of stimulation. This included morphological assessments of the cells, viability, as well as shape and fiber outgrowth relative to the orientation of the direct current electric field. We also undertook enzyme-linked immunosorbent assays and western immunoblotting to identify which molecular pathways were affected by direct current electric fields. In response to direct current electric field, neurons developed an elongated cell body shape with neurite outgrowth that was associated with a significant increase in growth associated protein-43. Fetal midbrain dopaminergic explants grown in a collagen gel matrix also showed a reorientation of their neurites towards the cathode. BV2 microglial cells adopted distinct morphological changes with an increase in cyclooxygenase-2 expression, but these were dependent on whether they had already been activated with lipopolysaccharide. Finally, astrocytes displayed elongated cell bodies with cellular filopodia that were oriented perpendicularly to the direct current electric field. We show that cells of the central nervous system can respond to direct current electric fields both in terms of their morphological shape and molecular expression of certain proteins, and this in turn can help us to begin understand the mechanisms underlying the clinical benefits of direct current electric field. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s)

Science.gov (United States)

2015-12-01

TRANSCRANIAL DIRECT CURRENT STIMULATION OF EXPRESSION OF IMMEDIATE EARLY GENES (IEG’S) Jessica...AND SUBTITLE Effects of Transcranial Direct Current Stimulation on Expression of Immediate Early Genes (IEG’s) 5a. CONTRACT NUMBER In-House 5b...community in better understanding what is occurring biologically during tDCS. 15. SUBJECT TERMS Transcranial direct current stimulation

Potential of energy saving with photovoltaic systems; Potencialidad de ahorro de energia con sistemas fotovoltaicos

Energy Technology Data Exchange (ETDEWEB)

Guzman S, Eusebio; Bratu S, Neagu [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)

1998-12-31

This paper presents an approach on the application of photovoltaic systems in energy saving. The problem of the electric energy demand in the coming years is analyzed and its consequences on the environment and on the energy reserves of conventional sources. A model of the electric circuit equivalent to a photovoltaic cell illustrates the behavior of the photovoltaic cell in function of the climatological conditions. The former in order to show some of the limiting factors in this type of generator. Also, the evolution of the applications of the photovoltaic systems and its forecasting in the installed capacity in the next 20 years, is described. [Espanol] En este trabajo se presenta un enfoque de la aplicacion de los sistemas fotovoltaicos en el ahorro de energia. Se plantea el problema del crecimiento de la demanda energetica en los proximos anos y sus consecuencias sobre el medio ambiente y las reservas de energia por fuentes convencionales. Un modelo del circuito electrico equivalente de una celda fotovoltaica ilustra el comportamiento del generador fotovoltaico en funcion de las condiciones climatologicas. Lo anterior con el fin de mostrar algunas limitantes de este tipo de generador. Tambien se describe la evolucion de las aplicaciones de los sistemas fotovoltaicos y el pronostico de la potencia instalada en los proximos 20 anos.

Potential of energy saving with photovoltaic systems; Potencialidad de ahorro de energia con sistemas fotovoltaicos

Energy Technology Data Exchange (ETDEWEB)

Guzman S, Eusebio; Bratu S, Neagu [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)

1999-12-31

This paper presents an approach on the application of photovoltaic systems in energy saving. The problem of the electric energy demand in the coming years is analyzed and its consequences on the environment and on the energy reserves of conventional sources. A model of the electric circuit equivalent to a photovoltaic cell illustrates the behavior of the photovoltaic cell in function of the climatological conditions. The former in order to show some of the limiting factors in this type of generator. Also, the evolution of the applications of the photovoltaic systems and its forecasting in the installed capacity in the next 20 years, is described. [Espanol] En este trabajo se presenta un enfoque de la aplicacion de los sistemas fotovoltaicos en el ahorro de energia. Se plantea el problema del crecimiento de la demanda energetica en los proximos anos y sus consecuencias sobre el medio ambiente y las reservas de energia por fuentes convencionales. Un modelo del circuito electrico equivalente de una celda fotovoltaica ilustra el comportamiento del generador fotovoltaico en funcion de las condiciones climatologicas. Lo anterior con el fin de mostrar algunas limitantes de este tipo de generador. Tambien se describe la evolucion de las aplicaciones de los sistemas fotovoltaicos y el pronostico de la potencia instalada en los proximos 20 anos.

Feasibility of transcranial direct current stimulation use in children aged 5 to 12 years.

Science.gov (United States)

Andrade, Agnes Carvalho; Magnavita, Guilherme Moreira; Allegro, Juleilda Valéria Brasil Nunes; Neto, Carlos Eduardo Borges Passos; Lucena, Rita de Cássia Saldanha; Fregni, Felipe

2014-10-01

Transcranial direct current stimulation is a noninvasive brain stimulation technique that has been studied for the treatment of neuropsychiatric disorders in adults, with minimal side effects. The objective of this study is to report the feasibility, tolerability, and the short-term adverse effects of transcranial direct current stimulation in children from 5 to 12 years of age. It is a naturalistic study of 14 children who underwent 10 sessions of transcranial direct current stimulation as an alternative, off-label, and open-label treatment for various languages disorders. Frequency, intensity, adverse effects, and perception of improvement reported by parents were collected. The main side effects detected were tingling (28.6%) and itching (28.6%), acute mood changes (42.9%), and irritability (35.7%). Transcranial direct current stimulation is a feasible and tolerable technique in children, although studies regarding plastic and cognitive changes in children are needed to confirm its safety. In conclusion, this is a naturalistic report in which we considered transcranial direct current stimulation as feasible in children. © The Author(s) 2013.

Current direction, benthic organisms, temperature, and wind direction data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 22 September 1977 - 30 November 1978 (NODC Accession 7900110)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, benthic organisms, temperature, and wind direction data were collected using moored current meter casts in the Gulf of Mexico from September 22,...

Transcranial Direct Current Stimulation Does Not Improve Language Outcome in Subacute Poststroke Aphasia.

Science.gov (United States)

Spielmann, Kerstin; van de Sandt-Koenderman, W Mieke E; Heijenbrok-Kal, Majanka H; Ribbers, Gerard M

2018-04-01

The aim of the present study is to investigate the effect of transcranial direct current stimulation on word-finding treatment outcome in subacute poststroke aphasia. In this multi-center, double-blind, randomized controlled trial with 6-month follow-up, we included 58 patients with subacute aphasia (transcranial direct current stimulation (1 mA, 20 minutes; experimental group) or sham transcranial direct current stimulation (control group) over the left inferior frontal gyrus. The primary outcome measure was the Boston Naming Test. Secondary outcome measures included naming performance for trained/untrained picture items and verbal communication. Both the experimental (n=26) and the control group (n=32) improved on the Boston Naming Test over the intervention period and 6-month follow-up; however, there were no significant differences between groups. Also for the secondary outcome measures, no significant differences were found. The results of the present study do not support an effect of transcranial direct current stimulation as an adjuvant treatment in subacute poststroke aphasia. URL: http://www.trialregister.nl/trialreg/admin/rctview.asp. Unique identifier: NTR4364. © 2018 American Heart Association, Inc.

Directed Current Without Dissipation: Reincarnation of a Maxwell-Loschmidt Demon

Science.gov (United States)

Goychuk, Igor; Haenggi, Peter

We investigate whether for initially localized particles a directed current in rocked periodic structures is possible in absence of a dissipative mechanism. With a pure Hamiltonian dynamics the breaking of Time-Reversal-Invariante presents anecessary condition to find nonzero current values. Numerical studies are presented for the classical Hamiltonian dynamical case. These support the fact that indeed a finite current does occur when a time-reversal symmetry-breaking signal, such as a harmonic mixing signal, is acting. To gain analytical insight we consider the coherent driven quantum transport in a one-dimensional tight-binding lattice. Here, a finite coherent current is absent for initially localized preparations; it emerges, however, when the initial preparation (with zero initial current) possesses finite coherence. The presence of phase fluctuations will eventually kill any finite current, thereby rendering the nondissipative currents a transient phenomenon.

Current status and future direction of the MONK software package

International Nuclear Information System (INIS)

Smith, Nigel; Armishaw, Malcolm; Cooper, Andrew

2003-01-01

The current status of the MONK criticality software package is summarized in terms of recent and current developments and envisaged directions for the future. The areas of the discussion are physics modeling, geometry modeling, source modeling, nuclear data, validation, supporting tools and customer services. In future development plan, MONK continues to be focused on meeting the short and long-term needs of the code user community. (J.P.N.)

Bancos Cooperativos y Sociedades de Ahorro y Crédito en El Salvador: modelo de supervisión prudencial y análisis empírico del coeficiente de solvencia

OpenAIRE

Hernández, Ana Verónica

2013-01-01

Estudio bibliográfico empírico, con el que se presenta una propuesta de supervisión para la superintendencia financiera de El Salvador, que incluye requisitos mínimos a considerar por el auditor, tomando como base Basilea II, III y siguiendo el Modelo OSFI de Canadá. Además se presenta un estudio empírico sobre los determinantes del coeficiente patrimonial en bancos cooperativos y sociedades de ahorro y crédito de El Salvador. Economía Financiera y Contabilidad Máster en Investigación ...

Proceedings of the 24. National seminar on the rational use of energy and exposition of equipment and services and 7. Binational seminar on energy saving [Selected Papers]; 24. Seminario nacional sobre el uso racional de energia y exposicion de equipos y servicios y 7. Seminario binacional de ahorro de energia. Memoria Tecnica. [Ponencias seleccionadas

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This document contains the technical briefings of the 24. National Seminar on the rational use of energy, and exhibition of the equipment and services and the 7. Binational seminar on energy saving, organized by the Asociacion de Profesionistas y Tecnicos en Aplicacion Energetica (ATPAE), in Ciudad Juarez, Chihuahua, Mexico, from November 9 to 11, 2005. This seminar dealt with subjects such as: electrical energy saving, energy distribution, solar energy, energy saving in compressed air, biomass, administration and control of the demand of the electrical energy, bioclimatic architecture, use of the compressed natural gas, renewable energy, co-generation, qualification and consultancy for the intelligent use of the energy in PyMES. [Spanish] Este documento contiene la memoria tecnica del 24 Seminario Nacional sobre el uso racional de energia, y exposicion de los equipos y servicios y el 7 Seminario binacional de ahorro de energia, organizado por la Asociacion de Tecnicos y Profesionistas en Aplicacion Energetica (ATPAE), en Ciudad Juarez, Chihuahua, Mexico, del 9 al 11 de noviembre del 2005. Este seminario trato temas tales como: ahorro de energia electrica, distribucion de la energia, energia solar, ahorro de energia en aire comprimido, biomasa, administracion y control de la demanda de la energia electrica, arquitectura bioclimatica, uso del gas natural comprimido, energia renovable, cogeneracion, capacitacion y consultoria para el uso inteligente de la energia en las Pymes.

Investigation of in vitro bone cell adhesion and proliferation on Ti using direct current stimulation

International Nuclear Information System (INIS)

Bodhak, Subhadip; Bose, Susmita; Kinsel, William C.; Bandyopadhyay, Amit

2012-01-01

Our objective was to establish an in vitro cell culture protocol to improve bone cell attachment and proliferation on Ti substrate using direct current stimulation. For this purpose, a custom made electrical stimulator was developed and a varying range of direct currents, from 5 to 25 μA, was used to study the current stimulation effect on bone cells cultured on conducting Ti samples in vitro. Cell–material interaction was studied for a maximum of 5 days by culturing with human fetal osteoblast cells (hFOB). The direct current was applied in every 8 h time interval and the duration of electrical stimulation was kept constant at 15 min for all cases. In vitro results showed that direct current stimulation significantly favored bone cell attachment and proliferation in comparison to nonstimulated Ti surface. Immunochemistry and confocal microscopy results confirmed that the cell adhesion was most pronounced on 25 μA direct current stimulated Ti surfaces as hFOB cells expressed higher vinculin protein with increasing amount of direct current. Furthermore, MTT assay results established that cells grew 30% higher in number under 25 μA electrical stimulation as compared to nonstimulated Ti surface after 5 days of culture period. In this work we have successfully established a simple and cost effective in vitro protocol offering easy and rapid analysis of bone cell–material interaction which can be used in promotion of bone cell attachment and growth on Ti substrate using direct current electrical stimulation in an in vitro model. - Highlights: ► D.C. stimulation was used to enhance in vitro bone cell adhesion and proliferation. ► Cells cultured on Ti were stimulated by using a custom made electrical stimulator. ► Optimization was performed by using a varying range of direct currents ∼ 5 to 25 μA. ► 25 μA stimulation was found most beneficial for promotion of cell adhesion/growth.

Innovations in electrophoretic deposition: Alternating current and pulsed direct current methods

International Nuclear Information System (INIS)

Chávez-Valdez, Alejandra; Boccaccini, Aldo R.

2012-01-01

This review summarizes emerging developments in the field of alternating current (AC) and pulsed direct current (DC) electrophoretic deposition (EPD) in aqueous or organic media. Numerous applications of AC-EPD are discussed including two major groups of investigations: (i) AC-EPD to suppress water hydrolysis at high voltages in inorganic (ceramic) coatings and (ii) AC-EPD for deposition of biological entities. The deposition, purification and manipulation of carbon nanotubes and nanoparticles by AC-EPD to form specific arrays, for development of sensors and other electronic devices and the application of AC-EPD as method for separation of particles according to their shape or size are also presented. Other applications reviewed relate to the fabrication by AC-EPD of toxic gas sensors from oxides and superconducting layers. The main materials being examined by AC-EPD are inorganic, including carbon nanotubes, TiO 2 nanoparticles, Al 2 O 3 , Si, SnO 2 , ZnO and WO 3 and biological entities, e.g. bacteria cells. For pulsed EPD, the applications reviewed are divided in pulsed current and pulsed voltage EPD. Among the applications of pulsed EPD, the formation of thick films from aqueous suspensions without water decomposition, the fabrication of multilayer and composite materials and the size-selective deposition of ceramic nanoparticles are the most important investigated to date, based on the quality of the coatings and deposits obtained and their relevance for applications.

National potential of saving of electricity in domestic refrigeration; Potencial nacional de ahorro de electricidad en refrigeracion domestica

Energy Technology Data Exchange (ETDEWEB)

Arroyo C, Fernando [Universidad Nacional Autonoma de Mexico (Mexico); Ambriz G, Juan Jose; Romero P, Hernando [Universidad Autonoma Metropolitana, (Mexico)

2003-07-01

In the present paper the evaluation of the potential of saving of electrical energy in Mexico is presented, by means of the substitution of old refrigerators of low efficiency by modern high efficiency ones. This potential is very ample, since the replacement of the old models by new follows a very slow curve, if the economic difficulties of the Mexican families are considered and that, on the other hand, the technology of the domestic refrigerators is so reliable that they have a very long life and they are not easily rejected. In field work have been found refrigerators operating with ages of more than 30 years and still 40. In Mexico, it is estimated that the refrigeration is responsible for around 29% of the of electricity consumption in homes settled in tempered climate and of 14 % in those of warm climate in which air conditioning is used. The proposal of this work is the organization of a governmental program of accelerated substitution of refrigerators that helps to acquire an efficient refrigerator and to reject the old ones. The results indicate that if a total renovation of the park of domestic refrigerators is made, the saving of electrical energy would reach the 5.2 TWh/a which represents the 44.5% of the total consumption of 11.7 TWh in a year. [Spanish] En el presente trabajo se presenta la evaluacion del potencial de ahorro de energia electrica en Mexico, mediante la substitucion de refrigeradores antiguos de baja eficiencia por modernos de alta eficiencia. Este potencial es muy amplio, ya que el reemplazo de los modelos viejos por nuevos sigue una curva muy lenta, si se consideran las dificultades economicas de las familias mexicanas y que, por otro lado, la tecnologia de los refrigeradores domesticos es tan confiable que tienen una vida muy larga y no se desechan facilmente. En trabajos de campo se han encontrado refrigeradores operando con edades de mas de 30 anos y aun 40. En Mexico, se estima que la refrigeracion es responsable de alrededor del

HIV vaccines: current challenges and future directions.

Science.gov (United States)

Avrett, Sam; Collins, Chris

2002-07-01

Volume seven of the Review will mark the tenth anniversary of the Canadian HIV/AIDS Legal Network with a series of articles that describe past developments and future directions in several areas of policy and law related to HIV/AIDS. The following article is the first of these, discussing current challenges and future directions in the development of and access to HIV vaccines. It argues that governments are under public health, ethical, and legal obligations to develop and provide access to HIV vaccines. It further explains what is required for governments to fulfill their obligations: additional commitment and resources for HIV vaccine development in the context of increased global research and development regarding diseases of the poor; increased support and advocacy for partnerships to develop HIV vaccines; enhanced regulatory capacity in every country to review, approve, and monitor HIV vaccines; and assurance of global supply of, procurement of, delivery of, and access to vaccines in the context of efforts to increase global access to public health measures and technologies.

Remesas y Ahorro de los Migrantes Michoacanos radicados en EUA. Un Diagnóstico Preliminar

Directory of Open Access Journals (Sweden)

Jerjes Aguirre Ochoa

2007-06-01

Full Text Available El objetivo de este artículo es realizar un diagnostico del potencial productivo del ahorro migrante para el caso del estado de Michoacán. Los datos obtenidos muestran un perfil de Michoacano radicado en EUA con ingresos suficientes para enviar remesas familiares a México pero limitados para realizar inversiones mayores a 200 dólares mensuales en Michoacán. Dentro de esa limitación, de contar con capital, los michoacanos manifestaron una preferencia por invertir en México y específicamente en su comunidad de origen. La preferencia de inversión mas citada es la compra de una vivienda o reparación de la misma. Asimismo, la corrupción y la inseguridad son señaladas como obstáculos para la inversión en México. Finalmente, el alto porcentaje de migrantes indocumentados encontrados en la encuesta refleja los profundos impactos que una reforma migratoria en EUA puede tener en la dinámica económica del estado. La migración a EUA puede dejar de convertirse en la válvula de escape para la población michoacana que no encuentre oportunidades laborales en Michoacán sumiendo a la entidad en graves problemas económicos y sociales.

Análisis de costes y ahorros potenciales relacionados con la utilización de pruebas preoperatorias en los hospitales de Canarias

Directory of Open Access Journals (Sweden)

López-Bastida J.

2003-01-01

Full Text Available Objetivos: Estimar el ahorro potencial que podría tener lugar en el Servicio Canario de Salud (SCS, a partir de una utilización apropiada científica de las pruebas preoperatorias, haciendo uso de la información obtenida de los 5 hospitales universitarios de la red pública. Métodos: Un total de 55 anestesiólogos (60% del SCS cumplimentaron un cuestionario. En éste se prestó especial atención a las pruebas preoperatorias más frecuentemente utilizadas, como la radiografía de tórax, el electrocardiograma, las pruebas de laboratorio y la espirometría. Los costes unitarios medios para las diferentes pruebas preoperatorias se obtuvieron de 2 hospitales participantes en el estudio. Para calcular los ahorros potenciales derivados del uso apropiado de las pruebas preoperatorias se han considerado varios escenarios caracterizados por diferentes hipótesis o grados de cumplimiento de un protocolo basado en el conocimiento científico, considerado como parámetro de referencia. Resultados: En el caso ideal de que se cumpliera el protocolo científico recomendado en el 100% de los 16.179 pacientes considerados ASA I y II, la repercusión económica sería notable, pues supondría una liberación de recursos sensible que podría ser utilizada para otros programas de salud. Estas cifras podrían alcanzar aproximadamente los 1,02 millones de euros, sin considerar el coste de la estancia preoperatoria. Esta cifra podría incrementarse hasta, aproximadamente, los 2,13 millones de euros si incluimos un día de estancia preoperatoria, y hasta los 3,24 millones de euros incluyendo 2 días de estancia preoperatoria. Conclusiones: La revisión reciente de la literatura científica y los resultados proporcionados por el cuestionario aplicado en el SCS indican que las pruebas preoperatorias alcanzan los mayores beneficios para los pacientes y para la sociedad si se guían por el conocimiento científico. Es posible, además, liberar recursos a partir de una

Evaluation of the energy saving potential in illumination using presence sensors; Evaluacion del potencial de ahorro de energia en iluminacion utilizando sensores de presencia

Energy Technology Data Exchange (ETDEWEB)

Cortes Eslava, Alejandro [Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D. F. (Mexico)

1999-07-01

The analysis and the evaluation of the energy saving that would provide a system of illumination controlled by sensors of presence in an enclosure with low transit, evaluating the economic profitability of the system is presented. The data, from which the analysis is sustained and the results are deducted, coming from the use and installation of a timer in the area. [Spanish] Se presenta el analisis y la evaluacion de los ahorros de energia que suministraria un sistema de iluminacion controlado por sensores de presencia en un recinto con bajo transito, evaluando la rentabilidad economica del sistema. Los datos, a partir de los cuales se sustenta el analisis y se deducen los resultados, provienen de la utilizacion e instalacion de un contador de tiempo de uso en el recinto.

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Science.gov (United States)

2010-07-01

..., portable and stationary direct-current machines. 75.703-3 Section 75.703-3 Mineral Resources MINE SAFETY... stationary direct-current machines. In grounding offtrack direct-current machines and the enclosures of their... requirements: (1) Installation of silicon diodes shall be restricted to electric equipment receiving power from...

Compulsory Checking of Nuclear Power Engineering Materials by Direct and Eddy Current

Science.gov (United States)

Larionov, V. V.; Lider, A. M.; Sednev, D. A.; Xu, Shupeng

2016-08-01

The testing technology of copper parts designed for dry storage of spent nuclear fuel with application of direct and eddy current has been developed. Measurements results of flaw quantity caused hydrogenation and oxidation processes are presented. Evolution of copper M 001 flaw structure during hydrogenation from gaseous medium is analyzed. It has been demonstrated that the dependence of copper p electrical resistance on number of flaws in its structure has dome shaped character and changes with eddy current frequency change. Number of flaws formed by hydrogen depends on direction (100) or (200) of the crystal structure of copper lattice.

Dependence of critical current density on crystalline direction in thin YBCO films

DEFF Research Database (Denmark)

Paturi, P.; Peurla, M.; Raittila, J.

2005-01-01

The dependence of critical current density (J(c)) on the angle between the current direction and the (100) direction in the ab-plane of thin YBCO films deposited on (001)-SrTiO3 from natiocrystalline and microcrystalline targets is studied using magneto-optical microscopy. In the films made from...... the nanocrystalline target it is found that J(c) does not depend on the angle whereas J(c) decreases with increasing angle in the films made from the microcrystalline target. The films were characterized by detailed X-ray diffraction measurements. The findings are explained in terms of a network of planar defects...

Marketing estratégico para incrementar la cartera de socios de la Cooperativa de Ahorro y Crédito ?Uniblock? ubicada en la ciudad de Latacunga en el período 2013

OpenAIRE

Borja Brazales, Yadira Paola

2015-01-01

1. Fundamentos Teóricos.-- 2. Metodología.-- 3.Resultados.-- 4. Propuesta.-- 5. Conclusiones y Recomendaciones El desarrollo del presente trabajo tiene como objetivo diseñar estrategias de marketing para incrementar la cartera de socios de la Cooperativa de Ahorro y Crédito ?Uniblock?. Está investigación consiste en realizar un análisis situacional de la cooperativa, por lo cual primero se elaboró el marco teórico que abarca cada una de las variables objeto de estudio incluidas sus respect...

Reparto de utilidades en las sociedades cooperativas de ahorro y préstamo ¿por qué son gravadas? un análisis sobre la aplicación de la carga fiscal

OpenAIRE

Ramos Andrade, Zahyra del Rocío

2015-01-01

En síntesis en la presente investigación se realizó un minucioso análisis en torno a las sociedades cooperativas de ahorro y préstamo, basándose la autora en una entidad denominada caja popular San Rafael. Llegando a la conclusión de que dichas empresas son personas morales lucrativas pues obtienen un beneficio económico a cambio de los servicios que presta, son generadoras de riqueza y obtienen utilidades; sin embargo, dichas utilidades no son gravadas debido a que la legislación determina q...

Modelo de auditoría informática basada en riesgos en ámbitos financieros. Aplicación de un caso de estudio a una cooperativa de ahorro y crédito

OpenAIRE

Quishpe Goyes, Bety Elizabeth; Vargas Cisneros, Marjori Silvana

2013-01-01

184 hojas : ilustraciones, 29 x 21 cm + CD-ROM 4848 El presente documento tiene como objetivo presentar un modelo que permite efectuar auditorías informáticas basadas en riesgos en ámbitos financieros, el cual fue aplicado a una Cooperativa de Ahorro y Crédito. El modelo propuesto se basa en normas y estándares nacionales e internacionales relacionados con la auditoría informática basada en riesgos, que permiten al auditor informático obtener las referencias necesarias para efectuar el exa...

Design aspects and conservation of roads in the saving of energy; Aspectos de diseno y conservacion de carreteras en el ahorro de energia

Energy Technology Data Exchange (ETDEWEB)

Lopez Cajun, Carlos S; Aguerrebere Salido, Roberto [Instituto Mexicano del Transporte, Queretaro (Mexico)

1993-12-31

In this paper the effects that on the fuel consumption the roads have for their slopes and roughness are presented. A mathematical model is presented which shows the relationship between the slope, the roughness coefficient and the required power to overcome the corresponding resistance; the former in order to predict the fuel consumption and therefore, the potential level of energy saving corresponding to this item. [Espanol] En este trabajo se presentan los efectos que sobre consumo de combustible se tienen, debido a las pendientes y rugosidades de las carreteras. Se presenta un modelo matematico que muestra la relacion entre la pendiente, el coeficiente de rodamiento y la potencia requerida para vencer las resistencias correspondientes; lo anterior con el fin de predecir el consumo de combustible y, por lo tanto, los niveles potenciales de ahorro de energia correspondientes a este rubro.

Design aspects and conservation of roads in the saving of energy; Aspectos de diseno y conservacion de carreteras en el ahorro de energia

Energy Technology Data Exchange (ETDEWEB)

Lopez Cajun, Carlos S.; Aguerrebere Salido, Roberto [Instituto Mexicano del Transporte, Queretaro (Mexico)

1992-12-31

In this paper the effects that on the fuel consumption the roads have for their slopes and roughness are presented. A mathematical model is presented which shows the relationship between the slope, the roughness coefficient and the required power to overcome the corresponding resistance; the former in order to predict the fuel consumption and therefore, the potential level of energy saving corresponding to this item. [Espanol] En este trabajo se presentan los efectos que sobre consumo de combustible se tienen, debido a las pendientes y rugosidades de las carreteras. Se presenta un modelo matematico que muestra la relacion entre la pendiente, el coeficiente de rodamiento y la potencia requerida para vencer las resistencias correspondientes; lo anterior con el fin de predecir el consumo de combustible y, por lo tanto, los niveles potenciales de ahorro de energia correspondientes a este rubro.

Evaluation of saving measurements and energetic efficiency in air-conditioning systems; Evaluacion de medidas de ahorro y eficiencia energetica en sistemas de climatizacion

Energy Technology Data Exchange (ETDEWEB)

Perez Lombard, L [Asociacion de Investigacion y Cooperacion de Andalucia (Spain); Ortiz, J [Building Research Establishment (United Kingdom); Riviere, P [Armines-ecole des mines de Paris (France)

2006-04-15

Buildings require an adequate air conditioning to offer workers a labor environment where there is thermal comfort. A study was performed in three different European places which count on several climates. The conclusion was the following: in order to analyze the energy efficiency in edifications it is fundamental the simulation tools use with the purpose of calculating the consumption and evaluating the saving measurements. [Spanish] Los edificios requieren de una climatizacion adecuada para que los que ahi operan puedan hacerlo dentro de un ambiente laboral donde exista el confort termico. Se llevo a cabo un estudio en tres lugares de Europa poseedores de diferentes climas y se concluyo que para poder analizar la eficiencia energetica de climatizacion en las edificaciones es imprescindible el uso de herramientas de simulacion con el proposito de calcular el consumo y evaluar las medidas de ahorro.

High-voltage direct-current circuit breakers

International Nuclear Information System (INIS)

Yoshioka, Y.; Hirasawa, K.

1991-01-01

This paper reports that in 1954 the first high-voltage direct-current (HVDC) transmission system was put into operation between Gotland and the mainland of Sweden. Its system voltage and capacity were 100 kV and 20 MW, respectively. Since then many HVDC transmission systems have been planned, constructed, or commissioned in more than 30 places worldwide, and their total capacity is close to 40 GW. Most systems commissioned to date are two-terminal schemes, and HVDC breakers are not yet used in the high-potential main circuit of those systems, because the system is expected to perform well using only converter/inverter control even at a fault stage of the transmission line. However, even in a two-terminal scheme there are not a few merits in using an HVDC breaker when the system has two parallel transmission lines, that is, when it is a double-circuit system

Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016.

Science.gov (United States)

Bikson, Marom; Grossman, Pnina; Thomas, Chris; Zannou, Adantchede Louis; Jiang, Jimmy; Adnan, Tatheer; Mourdoukoutas, Antonios P; Kronberg, Greg; Truong, Dennis; Boggio, Paulo; Brunoni, André R; Charvet, Leigh; Fregni, Felipe; Fritsch, Brita; Gillick, Bernadette; Hamilton, Roy H; Hampstead, Benjamin M; Jankord, Ryan; Kirton, Adam; Knotkova, Helena; Liebetanz, David; Liu, Anli; Loo, Colleen; Nitsche, Michael A; Reis, Janine; Richardson, Jessica D; Rotenberg, Alexander; Turkeltaub, Peter E; Woods, Adam J

2016-01-01

This review updates and consolidates evidence on the safety of transcranial Direct Current Stimulation (tDCS). Safety is here operationally defined by, and limited to, the absence of evidence for a Serious Adverse Effect, the criteria for which are rigorously defined. This review adopts an evidence-based approach, based on an aggregation of experience from human trials, taking care not to confuse speculation on potential hazards or lack of data to refute such speculation with evidence for risk. Safety data from animal tests for tissue damage are reviewed with systematic consideration of translation to humans. Arbitrary safety considerations are avoided. Computational models are used to relate dose to brain exposure in humans and animals. We review relevant dose-response curves and dose metrics (e.g. current, duration, current density, charge, charge density) for meaningful safety standards. Special consideration is given to theoretically vulnerable populations including children and the elderly, subjects with mood disorders, epilepsy, stroke, implants, and home users. Evidence from relevant animal models indicates that brain injury by Direct Current Stimulation (DCS) occurs at predicted brain current densities (6.3-13 A/m(2)) that are over an order of magnitude above those produced by conventional tDCS. To date, the use of conventional tDCS protocols in human trials (≤40 min, ≤4 milliamperes, ≤7.2 Coulombs) has not produced any reports of a Serious Adverse Effect or irreversible injury across over 33,200 sessions and 1000 subjects with repeated sessions. This includes a wide variety of subjects, including persons from potentially vulnerable populations. Copyright © 2016 Elsevier Inc. All rights reserved.

High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

Energy Technology Data Exchange (ETDEWEB)

Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2015-02-14

We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

Transcranial direct-current stimulation as treatment in epilepsy.

Science.gov (United States)

Gschwind, Markus; Seeck, Margitta

2016-12-01

Neuromodulation (NM) is a complementary therapy for patients with drug-resistant epilepsy. Vagal nerve stimulation and deep brain stimulation of the anterior thalamus are established techniques and have shown their efficacy in lowering seizure frequency, but they are invasive and rarely render patients seizure-free. Non-invasive NM techniques are therefore increasingly investigated in a clinical context. Areas covered: Current knowledge about transcranial direct-current stimulation (tDCS) and other non-invasive NM in patients with epilepsy, based on the available animal and clinical studies from PubMed search. Expert commentary: tDCS modulates neuronal membrane potentials, and consequently alters cortical excitability. Cathodal stimulation leads to cortical inhibition, which is of particular importance in epilepsy treatment. The antiepileptic efficacy is promising but still lacks systematic studies. The beneficial effect, seen in ~20%, outlasts the duration of stimulation, indicating neuronal plasticity and is therefore of great interest to obtain long-term effects.

Propuesta de nuevas opciones de inversión y gestión de la cartera de inversiones de la Junta Administradora de Ahorro y Préstamo de la Universidad de Costa Rica

OpenAIRE

López Bogantes, Randy Alberto

2014-01-01

Tesis de maestría -- Universidad de Costa Rica. Posgrado en Administración y Dirección de Empresas. Maestría Profesional en Administración y Dirección de Empresas con énfasis en Finanzas, 2014 El objetivo general del proyecto es proponer alternativas adicionales de inversión más rentables que permitan a la Junta Administradora de Ahorro y Préstamo de la Universidad de Costa Rica una estructura óptima del portafolio de acuerdo con la normativa interna, al lograr el mejor rendimiento posible...

Análisis de la estructura financiera para la toma de decisiones gerenciales en la Junta Administradora del Fondo de Ahorro y Préstamo de la Universidad de Costa Rica

OpenAIRE

Rojas González, Catalina

2012-01-01

Tesis de maestría -- Universidad de Costa Rica. Posgrado en Administración y Dirección de Empresas. Maestría Profesional en Administración y Dirección de Empresas con énfasis en Finanzas, 2012 El objetivo general del trabajo es elaborar un análisis detallado de los estados financieros de la Junta Administradora del Fondo de Ahorro y Préstamo (JAFAP) de la Universidad de Costa Rica para el período comprendido entre el 31 de diciembre de 2009 y el 31 de diciembre de 2010, con el objetivo de ...

Direct-current nanogenerator driven by ultrasonic waves.

Science.gov (United States)

Wang, Xudong; Song, Jinhui; Liu, Jin; Wang, Zhong Lin

2007-04-06

We have developed a nanowire nanogenerator that is driven by an ultrasonic wave to produce continuous direct-current output. The nanogenerator was fabricated with vertically aligned zinc oxide nanowire arrays that were placed beneath a zigzag metal electrode with a small gap. The wave drives the electrode up and down to bend and/or vibrate the nanowires. A piezoelectric-semiconducting coupling process converts mechanical energy into electricity. The zigzag electrode acts as an array of parallel integrated metal tips that simultaneously and continuously create, collect, and output electricity from all of the nanowires. The approach presents an adaptable, mobile, and cost-effective technology for harvesting energy from the environment, and it offers a potential solution for powering nanodevices and nanosystems.

Cerebellar transcranial direct current stimulation in patients with ataxia: A double-blind, randomized, sham-controlled study.

Science.gov (United States)

Benussi, Alberto; Koch, Giacomo; Cotelli, Maria; Padovani, Alessandro; Borroni, Barbara

2015-10-01

Numerous studies have highlighted the possibility of modulating the excitability of cerebellar circuits using transcranial direct current stimulation. The present study investigated whether a single session of cerebellar anodal transcranial direct current stimulation could improve symptoms in patients with ataxia. Nineteen patients with ataxia underwent a clinical and functional evaluation pre- and post-double-blind, randomized, sham, or anodal transcranial direct current stimulation. There was a significant interaction between treatment and time on the Scale for the Assessment and Rating of Ataxia, on the International Cooperative Ataxia Rating Scale, on the 9-Hole Peg Test, and on the 8-Meter Walking Time (P transcranial direct current stimulation can transiently improve symptoms in patients with ataxia and might represent a promising tool for future rehabilitative approaches. © 2015 International Parkinson and Movement Disorder Society.

Modelling the effect of electrode displacement on transcranial direct current stimulation (tDCS)

Science.gov (United States)

Ramaraju, Sriharsha; Roula, Mohammed A.; McCarthy, Peter W.

2018-02-01

Objective. Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers a low-intensity, direct current to cortical areas with the purpose of modulating underlying brain activity. Recent studies have reported inconsistencies in tDCS outcomes. The underlying assumption of many tDCS studies has been that replication of electrode montage equates to replicating stimulation conditions. It is possible however that anatomical difference between subjects, as well as inherent inaccuracies in montage placement, could affect current flow to targeted areas. The hypothesis that stimulation of a defined brain region will be stable under small displacements was tested. Approach. Initially, we compared the total simulated current flowing through ten specific brain areas for four commonly used tDCS montages: F3-Fp2, C3-Fp2, Fp1-F4, and P3-P4 using the software tool COMETS. The effect of a slight (~1 cm in each of four directions) anode displacement on the simulated regional current density for each of the four tDCS montages was then determined. Current flow was calculated and compared through ten segmented brain areas to determine the effect of montage type and displacement. The regional currents, as well as the localised current densities, were compared with the original electrode location, for each of these new positions. Main results. Recommendations for montages that maximise stimulation current for the ten brain regions are considered. We noted that the extent to which stimulation is affected by electrode displacement varies depending on both area and montage type. The F3-Fp2 montage was found to be the least stable with up to 38% change in average current density in the left frontal lobe while the Fp1-F4 montage was found to the most stable exhibiting only 1% change when electrodes were displaced. Significance. These results indicate that even relatively small changes in stimulation electrode placement appear to result in surprisingly large

Spectrochemical analysis of plutonium using direct current plasma emission spectrometry

International Nuclear Information System (INIS)

Morris, W.F.; Fadeff, S.K.; Torres, S.

1983-01-01

One year ago, LLNL was just completing the installation of a Direct Current Plasma (DCP) spectrometer for the analysis of Pu and Pu alloys. The installation was completed in December 1982 and has been utilized regularly for Pu analysis since then. This paper discusses the experience with the instrument and some data demonstrating its performance

Use of Direct Current Resistivity Measurements to Assess AISI 304 Austenitic Stainless Steel Sensitization

OpenAIRE

Mesquita, Ramaiany Carneiro; Mecury, José Manoel Rivas; Tanaka, Auro Atsumi; Sousa, Regina Célia de

2015-01-01

This paper describes the feasibility of using direct current electrical resistivity measurements to evaluate AISI 304 austenitic stainless steel sensitization. ASTM A262 – Practice A and double loop electrochemical potentiodynamic reactivation (DL-EPR) tests were performed to assess the degree of sensitization (DoS) qualitatively and quantitatively, and electrical resistivity (ER) was measured by the four-point direct-current potential drop method. The results indicate that the DoS incr...

Propuesta de un sistema de aprovechamiento de agua lluvia como alternativa para el ahorro de agua potable, en la institución educativa María Auxiliadora de Caldas, Antioquia

Directory of Open Access Journals (Sweden)

Palacio Castañeda Natalia

2011-11-01

Full Text Available El aprovechamiento del agua lluvia es una práctica interesante, tanto ambiental como económicamente, si se tiene en cuenta la gran demanda del recurso sobre las cuencas hidrográficas, el alto grado de contaminación de las fuentes superficiales y los elevados costos por el consumo de agua potable en una institución educativa. Este proyecto presenta la ingeniería conceptual de una propuesta de diseño de un si stema de aprovechamiento de agua lluvia como alternativa para el ahorro de agua potable en usos tales como la descarga de sanitarios, el lavado de zonas comunes, entre otros. Se presenta, adicionalmente, un análisis aproximado de la viabilidad técnica y económica de dicho aprovechamiento en una institución educativa del municipio de Caldas, Antioquia. Se desarrollan en este documento tres aspectos principales: el cálculo de los volúmenes disponibles de agua lluvia en la zona, la evaluación del volumen de agua potable ahorrado con el aprovechamiento del agua lluvia, la estimación del presupuesto para la construcción del sistema y la proyección del ahorro generado al utilizarlo. Los resultados sugieren que el aprovechamiento de agua lluvia es una opción técnicamente viable, pero financieramente no, pues la inversión inicial es alta, por lo que es importante buscar financiación externa para desarrollar este tipo de proyectos que representan una solución interesante para contribuir al desarrollo sostenible de la institución educativa.

Virtual Inertia: Current Trends and Future Directions

Directory of Open Access Journals (Sweden)

Ujjwol Tamrakar

2017-06-01

Full Text Available The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.

Strategies for energy saving in buildings by means of automatic control; Estrategias de ahorro de energia en inmuebles mediante el control automatico

Energy Technology Data Exchange (ETDEWEB)

Garcia Trujillo, Oscar [Johnson Controls de Mexico S. A. de C. V., Mexico, D. F. (Mexico)

1998-12-31

In this paper some of the measures and strategies for energy saving that can be applied in different types of buildings, mainly in hotels and office buildings, are presented. The proposed actions are accomplished with the aid of the automatic control equipment and the operation and/or maintenance personnel that supervises and establishes the control parameters of each one of the strategies than are focused to the appropriate utilization of the electric energy. [Espanol] En este documento se presentan algunas de las medidas y estrategias de ahorro de energia que pueden ser aplicadas en diferentes tipos de inmuebles, principalmente en hoteles y en edificios de oficinas. Las acciones propuestas son realizadas con la ayuda del equipo de control automatico y del personal de operacion y/o mantenimiento quien supervisa y establece los parametros de control de cada una de las estrategias que son destinadas a la buena utilizacion de la energia electrica.

Administración estratégica y gobernabilidad en las cooperativas de ahorro y crédito del cantón Portoviejo

Directory of Open Access Journals (Sweden)

Dianexy Viviana Carreño

2014-12-01

Full Text Available Las Cooperativas de Ahorro y Crédito (CAC’s tienen una activa participación en el crecimiento y desarrollo económico del Ecuador, lo que permite desarrollar un estudio en la provincia de Manabí, tomando una muestra deliberada en el cantón Portoviejo, que concentra el 40% de las cooperativas que operan en la provincia; se utilizó la encuesta como técnica de recolección de datos, y se aplicó a los gerentes, presidentes de los Consejos de Administración y de vigilancia de diez CAC’s; A modo de conclusión es necesario recomendar promover el fortalecimiento y expansión con carácter holístico, a través de capacitación permanente y puesta en práctica de la Administración Estratégica, para alcanzar una mejor posición en el mercado, ganar la lealtad de los socios y atraer nuevos miembros.

Strategies for energy saving in buildings by means of automatic control; Estrategias de ahorro de energia en inmuebles mediante el control automatico

Energy Technology Data Exchange (ETDEWEB)

Garcia Trujillo, Oscar [Johnson Controls de Mexico S. A. de C. V., Mexico, D. F. (Mexico)

1999-12-31

In this paper some of the measures and strategies for energy saving that can be applied in different types of buildings, mainly in hotels and office buildings, are presented. The proposed actions are accomplished with the aid of the automatic control equipment and the operation and/or maintenance personnel that supervises and establishes the control parameters of each one of the strategies than are focused to the appropriate utilization of the electric energy. [Espanol] En este documento se presentan algunas de las medidas y estrategias de ahorro de energia que pueden ser aplicadas en diferentes tipos de inmuebles, principalmente en hoteles y en edificios de oficinas. Las acciones propuestas son realizadas con la ayuda del equipo de control automatico y del personal de operacion y/o mantenimiento quien supervisa y establece los parametros de control de cada una de las estrategias que son destinadas a la buena utilizacion de la energia electrica.

Pharmacologic versus direct-current electrical cardioversion of atrial flutter and fibrillation

NARCIS (Netherlands)

Van Gelder, IC; Tuinenburg, AE; Schoonderwoerd, BS; Tieleman, RG; Crijns, HJGM

1999-01-01

Conversion of atrial flutter and atrial fibrillation (AF) can be achieved by either pharmacologic or direct-current (DC) electrical cardioversion. DC electrical cardioversion is more effective and restores sinus rhythm instantaneously; however, general anesthesia is necessary, which can cause severe

Non-Cyanide Electrodeposited Ag–PTFE Composite Coating Using Direct or Pulsed Current Deposition

Directory of Open Access Journals (Sweden)

Raymond Sieh

2016-07-01

Full Text Available The effects of FC-4 cationic surfactant on electrodeposited Ag–PTFE composite coating using direct or pulsed currents were studied using scanning electron microscope (SEM, energy dispersive X-ray (EDS, optical microscope, and a linear tribometer. FC-4:PTFE in various ratios were added to a non-cyanide succinimide silver complex bath. Direct or pulsed current method was used at a constant current density to enable comparison between both methods. A high incorporation rate of PTFE was successfully achieved, with pulsed current being highly useful in increasing the amount of PTFE in the composite coating. The study of coating wear under sliding showed that a large majority of the electrodeposited coatings still managed to adhere to the substrate, even after 10 wear cycles of sliding tests. Performance improvements were achieved on all the samples with a coefficient of friction (CoF between 0.06 and 0.12.

Performance evaluation of directly photovoltaic powered DC PM (direct current permanent magnet) motor – propeller thrust system

International Nuclear Information System (INIS)

Atlam, Ozcan; Kolhe, Mohan

2013-01-01

Photovoltaic (PV) powered directly coupled electro-mechanical system has wide applications (e.g. PV powered cooling fans in green houses, PV water pumping system, solar vehicles). The objective of this work is to analyse the operation of directly PV powered DC PM (direct current permanent magnet) motor – propeller system for selection of motor parameters. The performance of such system mainly depends on the incident solar radiation, operating cell temperature, DC motor and propeller load parameters. It is observed that the operating points of the PV DC PM motor – propeller system matches very closely with the maximum power points (MPPs) of the PV array, if the DC PM motor – propeller parameters have been properly selected. It is found that for a specific application of such type of system, matching of torque–speed operating points with respect to the maximum power points of PV array are very important. It is ascertained through results that the DC PM motor's armature resistance, magnetic field constant, starting current to overcome the starting torque and torque coefficient are the main parameters. In designing a PV powered DC PM motor for a specific application, selection of these parameters are important for maximum utilization of the PV array output. The results of this system are useful for designing of directly PV powered DC PM motor's for aerodynamic applications. - Highlights: • We analyse the performance of directly PV powered DC PM motor – propeller system. • We examine PV electro-mechanical system for selection of DC motor parameters. • Matching of torque–speed curve to maximum power points of PV array is important

Transcranial direct current stimulation for depression in Alzheimer's disease: study protocol for a randomized controlled trial.

Science.gov (United States)

Narita, Zui; Yokoi, Yuma

2017-06-19

Patients with Alzheimer's disease frequently elicit neuropsychiatric symptoms as well as cognitive deficits. Above all, depression is one of the most common neuropsychiatric symptoms in Alzheimer's disease but antidepressant drugs have not shown significant beneficial effects on it. Moreover, electroconvulsive therapy has not ensured its safety for potential severe adverse events although it does show beneficial clinical effect. Transcranial direct current stimulation can be the safe alternative of neuromodulation, which applies weak direct electrical current to the brain. Although transcranial direct current stimulation has plausible evidence for its effect on depression in young adult patients, no study has explored it in older subjects with depression in Alzheimer's disease. Therefore, we present a study protocol designed to evaluate the safety and clinical effect of transcranial direct current stimulation on depression in Alzheimer's disease in subjects aged over 65 years. This is a two-arm, parallel-design, randomized controlled trial, in which patients and assessors will be blinded. Subjects will be randomized to either an active or a sham transcranial direct current stimulation group. Participants in both groups will be evaluated at baseline, immediately, and 2 weeks after the intervention. This study investigates the safety and effect of transcranial direct current stimulation that may bring a significant impact on both depression and cognition in patients with Alzheimer's disease, and may be useful to enhance their quality of life. ClinicalTrials.gov, NCT02351388 . Registered on 27 January 2015. Last updated on 30 May 2016.

Augmentation of Fear Extinction by Transcranial Direct Current Stimulation (tDCS

Directory of Open Access Journals (Sweden)

Natalie Dittert

2018-04-01

Full Text Available Although posttraumatic stress disorder (PTSD; DSM-V 309.82 and anxiety disorders (DSM-V 300.xx are widely spread mental disorders, the effectiveness of their therapy is still unsatisfying. Non-invasive brain-stimulation techniques like transcranial direct current stimulation (tDCS might be an option to improve extinction learning, which is a main functional factor of exposure-based therapy for anxiety disorders. To examine this hypothesis, we used a fear conditioning paradigm with female faces as conditioned stimuli (CS and a 95-dB female scream as unconditioned stimulus (UCS. We aimed to perform a tDCS of the ventromedial prefrontal cortex (vmPFC, which is mainly involved in the control of extinction-processes. Therefore, we applied two 4 × 4 cm electrodes approximately at the EEG-positions F7 and F8 and used a direct current of 1.5 mA. The 20-min stimulation was started during a 10-min break between acquisition and extinction and went on overall extinction-trials. The healthy participants were randomly assigned in two double-blinded process into two sham stimulation and two verum stimulation groups with opposite current flow directions. To measure the fear reactions, we used skin conductance responses (SCR and subjective ratings. We performed a generalized estimating equations model for the SCR to assess the impact of tDCS and current flow direction on extinction processes for all subjects that showed a successful conditioning (N = 84. The results indicate that tDCS accelerates early extinction processes with a significantly faster loss of CS+/CS– discrimination. The discrimination loss was driven by a significant decrease in reaction toward the CS+ as well as an increase in reaction toward the CS– in the tDCS verum groups, whereas the sham groups showed no significant reaction changes during this period. Therefore, we assume that tDCS of the vmPFC can be used to enhance early extinction processes successfully. But before it should be

Neuroprotective effect of cathodal transcranial direct current stimulation in a rat stroke model.

Science.gov (United States)

Notturno, Francesca; Pace, Marta; Zappasodi, Filippo; Cam, Etrugul; Bassetti, Claudio L; Uncini, Antonino

2014-07-15

Experimental focal brain ischemia generates in the penumbra recurrent depolarizations which spread across the injured cortex inducing infarct growth. Transcranial direct current stimulation can induce a lasting, polarity-specific, modulation of cortical excitability. To verify whether cathodal transcranial direct current stimulation could reduce the infarct size and the number of depolarizations, focal ischemia was induced in the rat by the 3 vessels occlusion technique. In the first experiment 12 ischemic rats received cathodal stimulation (alternating 15 min on and 15 min off) starting 45 min after middle cerebral artery occlusion and lasting 4 h. In the second experiment 12 ischemic rats received cathodal transcranial direct current stimulation with the same protocol but starting soon after middle cerebral artery occlusion and lasting 6 h. In both experiments controls were 12 ischemic rats not receiving stimulation. Cathodal stimulation reduced the infarct volume in the first experiment by 20% (p=0.002) and in the second by 30% (p=0.003). The area of cerebral infarction was smaller in animals receiving cathodal stimulation in both experiments (p=0.005). Cathodal stimulation reduced the number of depolarizations (p=0.023) and infarct volume correlated with the number of depolarizations (p=0.048). Our findings indicate that cathodal transcranial direct current stimulation exert a neuroprotective effect in the acute phase of stroke possibly decreasing the number of spreading depolarizations. These findings may have translational relevance and open a new avenue in neuroprotection of stroke in humans. Copyright © 2014. Published by Elsevier B.V.

Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study.

Science.gov (United States)

Santos, Michele Devido; Gagliardi, Rubens José; Mac-Kay, Ana Paula Machado Goyano; Boggio, Paulo Sergio; Lianza, Roberta; Fregni, Felipe

2013-01-01

Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. Prospective cohort study developed in a public university hospital. Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034), naming (P = 0.041) and verbal fluency for names of animals (P = 0.038). Improved scores for performing these three tasks were seen after stimulation. We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

Modeling of the Direct Current Generator Including the Magnetic Saturation and Temperature Effects

Directory of Open Access Journals (Sweden)

Alfonso J. Mercado-Samur

2013-11-01

Full Text Available In this paper the inclusion of temperature effect on the field resistance on the direct current generator model DC1A, which is valid to stability studies is proposed. First, the linear generator model is presented, after the effect of magnetic saturation and the change in the resistance value due to temperature produced by the field current are included. The comparison of experimental results and model simulations to validate the model is used. A direct current generator model which is a better representation of the generator is obtained. Visual comparison between simulations and experimental results shows the success of the proposed model, because it presents the lowest error of the compared models. The accuracy of the proposed model is observed via Modified Normalized Sum of Squared Errors index equal to 3.8979%.

Current direction-dependent modulation of human hand motor function by intermittent theta burst stimulation (iTBS).

Science.gov (United States)

Shirota, Yuichiro; Dhaka, Suman; Paulus, Walter; Sommer, Martin

2017-05-22

Transcranial magnetic stimulation (TMS) with different current directions can activate different sets of neurons. Current direction can also affect the results of repetitive TMS. To test the influence of uni-directional intermittent theta burst stimulation (iTBS) using different current directions, namely posteroanterior (PA) and anteroposterior (AP), on motor behaviour. In a cross-over design, PA- and AP-iTBS was applied over the left primary motor cortex in 19 healthy, right-handed volunteers. Performance of a finger-tapping task was recorded before and 0, 10, 20, and 30min after the iTBS. The task was conducted with the right and left hands separately at each time point. As a control, AP-iTBS with reduced intensity was applied to 14 participants in a separate session (AP weak condition). The finger-tapping count with the left hand was decreased after PA-iTBS. Neither AP- nor AP weak -iTBS altered the performance. Current direction had a significant impact on the after-effects of iTBS. Copyright © 2017 Elsevier B.V. All rights reserved.

Mild cognitive impairment in Parkinson's disease is improved by transcranial direct current stimulation combined with physical therapy.

Science.gov (United States)

Manenti, Rosa; Brambilla, Michela; Benussi, Alberto; Rosini, Sandra; Cobelli, Chiara; Ferrari, Clarissa; Petesi, Michela; Orizio, Italo; Padovani, Alessandro; Borroni, Barbara; Cotelli, Maria

2016-05-01

Parkinson's disease (PD) is characterized by both motor and cognitive deficits. In PD, physical exercise has been found to improve physical functioning. Recent studies demonstrated that repeated sessions of transcranial direct current stimulation led to an increased performance in cognitive and motor tasks in patients with PD. The present study investigated the effects of anodal transcranial direct current stimulation applied over the dorsolateral prefrontal cortex and combined with physical therapy in PD patients. A total of 20 patients with PD were assigned to 1 of 2 study groups: group 1, anodal transcranial direct current stimulation plus physical therapy (n = 10) or group 2, placebo transcranial direct current stimulation plus physical therapy (n = 10). The 2 weeks of treatment consisted of daily direct current stimulation application for 25 minutes during physical therapy. Long-term effects of treatment were evaluated on clinical, neuropsychological, and motor task performance at 3-month follow-up. An improvement in motor abilities and a reduction of depressive symptoms were observed in both groups after the end of treatment and at 3-month follow-up. The Parkinson's Disease Cognitive Rating Scale and verbal fluency test performances increased only in the anodal direct current stimulation group with a stable effect at follow-up. The application of anodal transcranial direct current stimulation may be a relevant tool to improve cognitive abilities in PD and might be a novel therapeutic strategy for PD patients with mild cognitive impairment. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Starting characteristics of direct current motors powered by solar cells

Science.gov (United States)

Singer, S.; Appelbaum, J.

1989-01-01

Direct current motors are used in photovoltaic systems. Important characteristics of electric motors are the starting to rated current and torque ratios. These ratios are dictated by the size of the solar cell array and are different for the various dc motor types. Discussed here is the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, and series and shunt excited motors when powered by solar cells for two cases: with and without a maximum-power-point-tracker (MPPT) included in the system. Comparing these two cases, one gets a torque magnification of about 3 for the permanent magnet motor and about 7 for other motor types. The calculation of the torques may assist the PV system designer to determine whether or not to include an MPPT in the system.

Determinants of the electric field during transcranial direct current stimulation

DEFF Research Database (Denmark)

Opitz, Alexander; Paulus, Walter; Will, Susanne

2015-01-01

Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features systematically shape the electric field...... over the motor cortex in small steps to examine the resulting changes of the electric field distribution in the underlying cortex. We examined the effect of skull thickness and composition on the passing currents showing that thinner skull regions lead to higher electric field strengths. This effect...... fluid and the skull, the gyral depth and the distance to the anode and cathode. These factors account for up to 50% of the spatial variation of the electric field strength. Further, we demonstrate that individual anatomical factors can lead to stimulation "hotspots" which are partly resistant...

Evaluación del punto de conmutación unicast- multicast para ahorro de potencia de transmisión en redes MBMS

Directory of Open Access Journals (Sweden)

Raúl Tamayo Fernández

2014-01-01

Full Text Available La oferta de aplicaciones y servicios multimedia para terminales móviles se hace principalmente a través de las redes celulares de tercera y cuarta generación (3G/4G existentes. El envío de los datos en este tipo de redes se realiza en modo unicast, es decir, a cada usuario se le dedican recursos de radio (ancho de banda y potencia de transmisión durante toda la sesión. Esto presenta algunos inconvenientes, tales como agotamiento rápido del ancho de banda del operador móvil, alto consumo de potencia de transmisión, incremento de la interferencia, y costos altos del servicio. Los operadores móviles requieren de nuevas tecnologías que optimicen el uso de sus recursos de radio y así lograr un mayor índice de penetración de los servicios. De ahí la necesidad de cambiar de paradigma hacia un modo de transmisión en multicast o broadcast, en el que una misma señal pueda recibirse por varios usuarios simultáneamente, de tal forma que los recursos de radio se puedan compartir. Para ello, la solución técnica sobre redes celulares LTE (Long Term Evolution se dio en la especificación 3GPP Release 6, llamada Servicio Multimedia por Broadcast/Multicast (MBMS, Multimedia Broadcast Multicast Service. La especificación de MBMS permite que una transmisión cambie de modo unicast a modo multicast a partir de un “punto de conmutación”, que determina el momento de hacer el cambio para obtener un ahorro tanto en ancho de banda como en potencia de transmisión. Este artículo presenta una evaluación para determinar los puntos de conmutación de modo de transmisión óptimos en el estándar MBMS para diferentes ambientes de propagación inalámbrica. Además, dado que MBMS se puede utilizar en topologías de Red de Frecuencia Única (SFN, Single Frequency Networks, que tienen la propiedad de “ganancia de red”, también se determina el ahorro de potencia de transmisión adicional que se obtiene en esta configuración.

Sistema de control de gestión de riesgo para la prevención del lavado de activos en la cooperativa de ahorro y crédito Sumak Samy Ltda. de la ciudad de Ambato.

OpenAIRE

Carrillo Sarabia, Patricia de las Mercedes

2017-01-01

1. Introducción. --2. Planteamiento de la Propuesta de Trabajo. --3. Marco Teórico. --4. Metodología. --5. Resultados. --6. Conclusiones y Recomendaciones. El presente trabajo tiene como objetivo fundamental el desarrollo de un Sistema de control de gestión de riesgo para la prevención del lavado de activos en la Cooperativa de Ahorro y Crédito Sumak Samy Ltda. en la ciudad de Ambato, el cual le permitirá a la cooperativa contar con el Nivel de riesgo de sus socios/clientes y aplicar polít...

The satisfaction of developing a project of electrical energy saving; La satisfaccion de desarrollar un proyecto de ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Arreola Suarez, Alejandro [Hotel Club Marival, Nuevo Vallarta, Nayarit (Mexico)

2002-09-01

The projects for the energy saving in hotels represent a great opportunity to reduce the operation costs in the demand and consumption of electrical energy, since the existing facilities can take advantage of new technologies in illumination, air conditioning, refrigeration and heating. By their constitution, the hotels work the year around uninterruptedly and must provide all type of services to the guests and working personnel, which originates that they consume great amounts of energy in air conditioning, lightning, laundry, etc., since the prestige of the installation depends on it. [Spanish] Los proyectos para el ahorro de energia en hoteles representan una gran oportunidad para reducir costos de operacion en la demanda y consumo de energia electrica, ya que las instalaciones existentes pueden aprovechar nuevas tecnologias en iluminacion, aire acondicionado, refrigeracion y calefaccion. Por su constitucion, los hoteles trabajan ininterrumpidamente todo el ano y deben proporcionar toda clase de servicios a los huespedes y personal que labora, lo cual origina que consuman grandes cantidades de energia en aire acondicionado, iluminacion, lavanderia, etc., pues de ello depende el prestigio de la instalacion.

Self-consistent model for pulsed direct-current N2 glow discharge

International Nuclear Information System (INIS)

Liu Chengsen

2005-01-01

A self-consistent analysis of a pulsed direct-current (DC) N 2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column). Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment. (authors)

Direct current hopping conductance along DNA chain

Institute of Scientific and Technical Information of China (English)

Ma Song-Shan; Xu Hui; Liu Xiao-Liang; Li Ming-Jun

2007-01-01

This paper proposes a model of direct current(DC) electron hopping transport in DNA,in which DNA is considered as a binary one-dimensional disordered system.To quantitatively study the DC conductivity in DNA,it numerically calculates the DC conductivity of DNA chains with difierent parameter values.The result shows that the DC conductivity of DNA chain increases with the increase of temperature.And the conductivity of DNA chain is depended on the probability P.which represents the degree of compositional disorder in a DNA sequence to some extent.For P＜0.5,the conductivity of DNA chain decreases with the increase of P,while for P≥0.5,the conductivity increases with the increase of p.The DC conductivity in DNA chain also varies with the change of the electric field,it presents non-Ohm's law conductivity characteristics.

Hydraulic speed variators for electrical energy saving; Variadores de velocidad hidraulicos para el ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Valera Negrete, Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Mexico, D. F. (Mexico)

1999-07-01

This paper shows the characteristics and applications of the hydraulic speed variators, where because of the conditions of the industrial processes it is necessary to vary the operation parameters, obtaining therefore an energy saving besides improving the control of these processes. In addition, the technical and economic evaluation is presented of a project of the Mazatlan Fossil Power Plant, in which it is intended to invest in the installation of a hydraulic speed variator connected to the forced draft fan of unit number three, which operates with an induction motor of 1,865 kW (2,500 H.P.), with a Voltage of 4,180 V at 1,180 rpm. [Spanish] El presente trabajo muestra las caracteristicas y aplicaciones de los variadores de velocidad hidraulicos, donde por las condiciones de los procesos industriales sea necesario variar los parametros de operacion, obteniendose asi un ahorro de energia ademas de mejorar el control de dichos procesos. Se presenta ademas la evaluacion tecnica y economica de un proyecto de la Planta Termoelectrica Mazatlan, en donde se pretende invertir en la instalacion de un variador de velocidad hidraulico acoplado al ventilador de tiro forzado de la unidad numero tres, el cual opera con un motor de induccion de 1,865 kW (2,500 H.P.), con un voltaje de 4,180 V y una velocidad de 1,180 rpm.

Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study

Directory of Open Access Journals (Sweden)

Michele Devido Santos

Full Text Available CONTEXT AND OBJECTIVE: Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. DESIGN AND SETTING: Prospective cohort study developed in a public university hospital. METHODS: Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. RESULTS: There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034, naming (P = 0.041 and verbal fluency for names of animals (P = 0.038. Improved scores for performing these three tasks were seen after stimulation. CONCLUSIONS: We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

Energy saving using solar filters with iron base in windows; Ahorro de energia usando filtros solares con base en hierro en ventanas

Energy Technology Data Exchange (ETDEWEB)

Chavez Galan, Jesus

2003-07-01

termico generado al interior de las edificaciones por las inadecuadas propiedades de los materiales de construccion, se desarrollaron en este trabajo filtros solares con base en hierro por medio de los cuales se logra un control selectivo de la radiacion solar que se transmite a traves de las ventanas. Estos filtros solares consisten en peliculas delgadas de FeO depositadas sobre sustratos de vidrio cal-sosa (el mas usado en nuestro pais para las edificaciones) de 600x300x3 mm, por medio de la tecnica de sputtering asistida con radiofrecuencia y magnetrones planos, partiendo de un blanco de hierro puro de 127x254 mm y usando un plasma de argon. Para obtener el grado de oxidacion deseado en el hierro, pequenas muestras (45 x 22 mm) fueron sometidas a un proceso de calentamiento en una atmosfera reductora constituida de 50% H{sub 2} + 50% N{sub 2}, durante un periodo de tiempo de 10 minutos a una temperatura de 400 C. Los filtros solares con base en FeO presentan una transmisividad de 30.2% para el intervalo visible del espectro electromagnetico (radiacion con longitud de onda de 380-780 nm), y de 39.9% para el infrarrojo cercano (radiacion con longitud de onda de 780-2500 nm); mientras que su reflectividad es de 17.5 y 19%, para los intervalos visibles e infrarrojo cercano del espectro electromagnetico respectivamente. Se realizo una simulacion, a traves del software Energy 10, del comportamiento energetico de una casa-habitacion cuando utilizan en las ventanas vidrios simples (una lamina) tipo cal-sosa, asi como tambien cuando esta misma edificacion usa en las ventanas los filtros solares con base en FeO desarrollados. Ambos casos se comparan obteniendose asi los posibles ahorros de energia por el uso de dichos filtros solares en las ventanas. Las simulaciones fueron llevadas a cabo para diferentes localidades del pais, obteniendose que los filtros solares con base en FeO desarrollados, permiten ahorros de energia principalmente por concepto de acondicionamiento de aire

Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study

OpenAIRE

Santos,Michele Devido; Gagliardi,Rubens José; Mac-Kay,Ana Paula Machado Goyano; Boggio,Paulo Sergio; Lianza,Roberta; Fregni,Felipe

2013-01-01

CONTEXT AND OBJECTIVE: Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. DESIGN AND SETTING: Prospective cohort study developed in a public university hospital. METHODS: Nineteen patients with ...

An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

Energy Technology Data Exchange (ETDEWEB)

Litzenberger, Wayne; Lava, Val

1994-08-01

References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

Combining physical training with transcranial direct current stimulation to improve gait in Parkinson's disease: a pilot randomized controlled study.

Science.gov (United States)

Kaski, D; Dominguez, R O; Allum, J H; Islam, A F; Bronstein, A M

2014-11-01

To improve gait and balance in patients with Parkinson's disease by combining anodal transcranial direct current stimulation with physical training. In a double-blind design, one group (physical training; n = 8) underwent gait and balance training during transcranial direct current stimulation (tDCS; real/sham). Real stimulation consisted of 15 minutes of 2 mA transcranial direct current stimulation over primary motor and premotor cortex. For sham, the current was switched off after 30 seconds. Patients received the opposite stimulation (sham/real) with physical training one week later; the second group (No physical training; n = 8) received stimulation (real/sham) but no training, and also repeated a sequential transcranial direct current stimulation session one week later (sham/real). Hospital Srio Libanes, Buenos Aires, Argentina. Sixteen community-dwelling patients with Parkinson's disease. Transcranial direct current stimulation with and without concomitant physical training. Gait velocity (primary gait outcome), stride length, timed 6-minute walk test, Timed Up and Go Test (secondary outcomes), and performance on the pull test (primary balance outcome). Transcranial direct current stimulation with physical training increased gait velocity (mean = 29.5%, SD = 13; p transcranial direct current stimulation alone. There was no isolated benefit of transcranial direct current stimulation alone. Although physical training improved gait velocity (mean = 15.5%, SD = 12.3; p = 0.03), these effects were comparatively less than with combined tDCS + physical therapy (p stimulation-related improvements were seen in patients with more advanced disease. Anodal transcranial direct current stimulation during physical training improves gait and balance in patients with Parkinson's disease. Power calculations revealed that 14 patients per treatment arm (α = 0.05; power = 0.8) are required for a definitive trial. © The Author(s) 2014.

The Philippine historical earthquakecatalog: its development, current stateand future directions

OpenAIRE

Bautista, M. L. P.; Bautista, B. C.

2004-01-01

This report will trace the development of the historical earthquake catalog of the Philippines, assess its present state and recommend future research directions. The current Philippine historical earthquake catalog is culled from various catalogs, both global and local, that were developed since the first Philippine catalog by Perrey was published in 1860. While early global catalogs gave simple mention of earthquakes in the Philippines, more focused earthquake catalogs about the Philippines...

Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

International Nuclear Information System (INIS)

Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do; Lee, Soo Yeol; Jung, Ki-Young

2008-01-01

The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

Determination of optimal electrode positions for transcranial direct current stimulation (tDCS)

Energy Technology Data Exchange (ETDEWEB)

Im, Chang-Hwan; Jung, Hui-Hun; Choi, Jung-Do [Department of Biomedical Engineering, Yonsei University, Wonju, 220-710 (Korea, Republic of); Lee, Soo Yeol [Department of Biomedical Engineering, Kyung Hee University, Suwon (Korea, Republic of); Jung, Ki-Young [Korea University Medical Center, Korea University College of Medicine, Seoul (Korea, Republic of)], E-mail: ich@yonsei.ac.kr

2008-06-07

The present study introduces a new approach to determining optimal electrode positions in transcranial direct current stimulation (tDCS). Electric field and 3D conduction current density were analyzed using 3D finite element method (FEM) formulated for a dc conduction problem. The electrode positions for minimal current injection were optimized by changing the Cartesian coordinate system into the spherical coordinate system and applying the (2+6) evolution strategy (ES) algorithm. Preliminary simulation studies applied to a standard three-layer head model demonstrated that the proposed approach is promising in enhancing the performance of tDCS. (note)

Descripción y análisis de la aplicación de la teoría general de las organizaciones en el modelo de gestión del Fondo Nacional de Ahorro, FNA

OpenAIRE

Isairías Mora, José Edgar; Lozada Angarita, Carlos Eduardo

2011-01-01

La tesis que a continuación se presenta corresponde a la Maestría en Dirección y Gerencia de Empresas de la Universidad del Rosario. En ella se revisan y analizan múltiples factores mediante los cuales se determina o no la aplicación de aplicación de la Teoría General de las organizaciones en la gestión del Fondo Nacional de Ahorro, FNA. de la ciudad de Bogotá. En ella se plantean los aspectos que se aplican de cada una de las siguientes teorías organizacionales o administrativas: Administrac...

Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

Energy Technology Data Exchange (ETDEWEB)

Lim, Sung Hun [Dept. of Electrical Engineering, Soongsil University, Seoul (Korea, Republic of); Han, Tae Hee [Dept. of Aero Materials Engineering, Jungwon University, Goesan (Korea, Republic of)

2017-06-15

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

Current limiting characteristics of transformer type SFCL with coupled secondary windings according to its winding direction

International Nuclear Information System (INIS)

Lim, Sung Hun; Han, Tae Hee

2017-01-01

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding

Combined Dextroamphetamine and Transcranial Direct Current Stimulation in Poststroke Aphasia.

Science.gov (United States)

Keser, Zafer; Dehgan, Michelle Weber; Shadravan, Shaparak; Yozbatiran, Nuray; Maher, Lynn M; Francisco, Gerard E

2017-10-01

There is a growing need for various effective adjunctive treatment options for speech recovery after stroke. A pharmacological agent combined with noninvasive brain stimulation has not been previously reported for poststroke aphasia recovery. In this "proof of concept" study, we aimed to test the safety of a combined intervention consisting of dextroamphetamine, transcranial direct current stimulation, and speech and language therapy in subjects with nonfluent aphasia. Ten subjects with chronic nonfluent aphasia underwent two experiments where they received dextroamphetamine or placebo along with transcranial direct current stimulation and speech and language therapy on two separate days. The Western Aphasia Battery-Revised was used to monitor changes in speech performance. No serious adverse events were observed. There was no significant increase in blood pressure with amphetamine or deterioration in speech and language performance. Western Aphasia Battery-Revised aphasia quotient and language quotient showed a statistically significant increase in the active experiment. Comparison of proportional changes of aphasia quotient and language quotient in active experiment with those in placebo experiment showed significant difference. We showed that the triple combination therapy is safe and implementable and seems to induce positive changes in speech and language performance in the patients with chronic nonfluent aphasia due to stroke.

Eddy current imaging. Simplifying the direct problem. Analysis of a 2D case with formulations

International Nuclear Information System (INIS)

Spineanu, A.; Zorgati, R.

1995-01-01

Eddy current non-destructive testing is used by EDF to detect faults affecting conductive objects such as steam generator tubes. A new technique, known as eddy current imaging, is being developed to facilitate diagnosis in this context. The first stage in this work, discussed in the present paper, consists in solving the direct problem. This entails determining the measurable quantities, on the basis of a thorough knowledge of the material considered. This was done by formulating the direct problem in terms of eddy currents in general 3D geometry context, applying distribution theory and Maxwell equations. Since no direct problem code was available we resorted to simplified situations. Taking care not to interfere with previous developments or those to be attempted in an inversion context, we studied the case of a flaw affecting a 2D structure, illuminated by a plane wave type probe. For this configuration, we studied the exact model and compared results with those of a linearized simplified model. This study emphasizes the ill-posed situation of the eddy current inverse problem related with the severe electromagnetic field attenuation. This means that regularization of the inverse problem, although absolutely necessary, will not be sufficient. Owing to the simplicity of the models available and implemented during the inversion process, processing real data would not yet be possible. We must first focus all our efforts on the direct 3 D problem, in conformity with the requirements of the inverse procedure ad describing a realistic eddy current NDT situation. At the same time, consideration should be given to the design of a specific probe customized for eddy current imaging. (authors). 9 refs., 5 figs., 3 appends

Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

Directory of Open Access Journals (Sweden)

Andisheh Bastani

Full Text Available BACKGROUND: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set. OBJECTIVE/HYPOTHESIS: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS current densities on corticospinal excitability. METHODS: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs of 0.013, 0.029, 0.058 and 0.083 mA/cm(2 were applied on twelve right-handed (mean age 34.5±10.32 yrs healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2 respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter. RESULTS: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2 and 0.029 mA/cm(2 (P = 0.003. There were no significant differences between excitability changes for the 0.013 mA/cm(2 and 0.058 mA/cm(2 (P = 0.080 or 0.013 mA/cm(2 and 0.083 mA/cm(2 (P = 0.484 conditions. CONCLUSION: This study found that a-tDCS with a current density of 0.013 mA/cm(2 induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2. The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

Transcranial Direct Current Stimulation in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder (ADHD): A Pilot Study.

Science.gov (United States)

Bandeira, Igor Dórea; Guimarães, Rachel Silvany Quadros; Jagersbacher, João Gabriel; Barretto, Thiago Lima; de Jesus-Silva, Jéssica Regina; Santos, Samantha Nunes; Argollo, Nayara; Lucena, Rita

2016-06-01

Studies investigating the possible benefits of transcranial direct current stimulation on left dorsolateral prefrontal cortex in children and adolescents with attention-deficit hyperactivity disorder (ADHD) have not been performed. This study assesses the effect of transcranial direct current stimulation in children and adolescents with ADHD on neuropsychological tests of visual attention, visual and verbal working memory, and inhibitory control. An auto-matched clinical trial was performed involving transcranial direct current stimulation in children and adolescents with ADHD, using SNAP-IV and subtests Vocabulary and Cubes of the Wechsler Intelligence Scale for Children III (WISC-III). Subjects were assessed before and after transcranial direct current stimulation sessions with the Digit Span subtest of the WISC-III, inhibitory control subtest of the NEPSY-II, Corsi cubes, and the Visual Attention Test (TAVIS-3). There were 9 individuals with ADHD according to Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria. There was statistically significant difference in some aspects of TAVIS-3 tests and the inhibitory control subtest of NEPSY-II. Transcranial direct current stimulation can be related to a more efficient processing speed, improved detection of stimuli, and improved ability to switch between an ongoing activity and a new one. © The Author(s) 2016.

Subcortical structures in humans can be facilitated by transcranial direct current stimulation

NARCIS (Netherlands)

Nonnekes, J.H.; Arrogi, A.; Munneke, M.A.M.; Asseldonk, E.H. van; Nijhuis, L.B.; Geurts, A.C.H.; Weerdesteyn, V.G.M.

2014-01-01

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

Subcortical Structures in Humans Can Be Facilitated by Transcranial Direct Current Stimulation

NARCIS (Netherlands)

Nonnekes, Johan Hendrik; Arrogi, A.; Munneke, M.A.M.; van Asseldonk, Edwin H.F.; Oude Nijhuis, L.B.; Geurts, A.C.; Weerdesteyn, V.

2014-01-01

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that alters cortical excitability. Interestingly, in recent animal studies facilitatory effects of tDCS have also been observed on subcortical structures. Here, we sought to provide evidence for the potential

Simulating Transcranial Direct Current Stimulation With a Detailed Anisotropic Human Head Model

NARCIS (Netherlands)

Rampersad, S.; Janssen, A.J.E.M.; Lucka, F.; Aydin, U.; Lanfer, B.; Lew, S.; Wolters, C.H.; Stegeman, D.F.; Oostendorp, T.F.

2014-01-01

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique able to induce long-lasting changes in cortical excitability that can benefit cognitive functioning and clinical treatment. In order to both better understand the mechanisms behind tDCS and possibly improve

Simulating transcranial direct current stimulation with a detailed anisotropic human head model

NARCIS (Netherlands)

Rampersad, S.M.; Janssen, A.M.; Lucka, F.; Aydin, U.; Lanfer, B.; Lew, S.; Wolters, C.H.; Stegeman, D.F.; Oostendorp, T.F.

2014-01-01

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique able to induce long-lasting changes in cortical excitability that can benefit cognitive functioning and clinical treatment. In order to both better understand the mechanisms behind tDCS and possibly improve

Method and system for a gas tube-based current source high voltage direct current transmission system

Science.gov (United States)

She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

2017-08-29

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

An image-guided transcranial direct current stimulation system: a pilot phantom study

International Nuclear Information System (INIS)

Jung, Young-Jin; Kim, Jung-Hoon; Kim, Daejeong; Im, Chang-Hwan

2013-01-01

In this study, an image-guided transcranial direct current stimulation (IG-tDCS) system that can deliver an increased stimulation current to a target brain area without the need to adjust the location of an active electrode was implemented. This IG-tDCS system was based on the array-type tDCS concept, which was validated through computer simulations in a previous study. Unlike a previous study, the present IG-tDCS system adopts a single reference electrode and an active electrode array consisting of 16 (4 × 4) sub-electrodes. The proposed IG-tDCS system is capable of shaping current flow inside the human head by controlling the input currents of the arrayed electrodes. Once a target brain area has been selected, the optimal injection current of each arrayed sub-electrode is evaluated automatically using a genetic algorithm in order to deliver the maximum available current to the target area. The operation of our pilot system was confirmed through a simple phantom experiment. (paper)

Multi-terminal direct-current grids modeling, analysis, and control

CERN Document Server

Chaudhuri, Nilanjan; Majumder, Rajat; Yazdani, Amirnaser

2014-01-01

A comprehensive modeling, analysis, and control design framework for multi-terminal direct current (MTDC) grids is presented together with their interaction with the surrounding AC networks and the impact on overall stability. The first book of its kind on the topic of multi-terminal DC (MTDC) grids  Presents a comprehensive modeling framework for MTDC grids which is compatible with the standard AC system modeling for stability studies Includes modal analysis and study of the interactions between the MTDC grid and the surrounding AC systems Addresses the problems of autonomous power sharing an

Diseño de un modelo de Administración de Riesgo Operativo aplicado al proceso de crédito en la Cooperativa de Ahorro y Crédito "Santa Ana de Nayón"

OpenAIRE

Sandoval Zambrano, Emma Patricia

2016-01-01

Este trabajo pretende aportar con un modelo de Riesgo Operativo en el Proceso de Crédito, a la Cooperativa de Ahorro y Crédito Santa Ana de Nayón, con el objetivo de disponer de una herramienta que permita mitigar posibles riesgos operativos a los que está expuesta. Intenta también motivar y concientizar a los directivos y a la gerencia de la importancia de la implementación de la Administración Integral de Riesgos, como estrategia institucional y de forma especial la gestión de riesgo operat...

Single-layer skull approximations perform well in transcranial direct current stimulation modeling

NARCIS (Netherlands)

Rampersad, S.M.; Stegeman, D.F.; Oostendorp, T.F.

2013-01-01

In modeling the effect of transcranial direct current stimulation, the representation of the skull is an important factor. In a spherical model, we compared a realistic skull modeling approach, in which the skull consisted of three isotropic layers, to anisotropic and isotropic single-layer

Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

Science.gov (United States)

Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

2011-07-01

Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

Consumer Mobile Health Apps: Current State, Barriers, and Future Directions.

Science.gov (United States)

Kao, Cheng-Kai; Liebovitz, David M

2017-05-01

This paper discusses the current state, barriers, and future directions of consumer-facing applications (apps). There are currently more than 165,000 mobile health apps publicly available in major app stores, the vast majority of which are designed for patients. The top 2 categories are wellness management and disease management apps, whereas other categories include self-diagnosis, medication reminder, and electronic patient portal apps. Apps specific to physical medicine and rehabilitation also are reviewed. These apps have the potential to provide low-cost, around-the-clock access to high-quality, evidence-based health information to end users on a global scale. However, they have not yet lived up to their potential due to multiple barriers, including lack of regulatory oversight, limited evidence-based literature, and concerns of privacy and security. The future directions may consist of improving data integration into the health care system, an interoperable app platform allowing access to electronic health record data, cloud-based personal health record across health care networks, and increasing app prescription by health care providers. For consumer mobile health apps to fully contribute value to health care delivery and chronic disease management, all stakeholders within the ecosystem must collaborate to overcome the significant barriers. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Transcranial direct current stimulation over left inferior frontal cortex improves speech fluency in adults who stutter.

Science.gov (United States)

Chesters, Jennifer; Möttönen, Riikka; Watkins, Kate E

2018-04-01

See Crinion (doi:10.1093/brain/awy075) for a scientific commentary on this article.Stuttering is a neurodevelopmental condition affecting 5% of children, and persisting in 1% of adults. Promoting lasting fluency improvement in adults who stutter is a particular challenge. Novel interventions to improve outcomes are of value, therefore. Previous work in patients with acquired motor and language disorders reported enhanced benefits of behavioural therapies when paired with transcranial direct current stimulation. Here, we report the results of the first trial investigating whether transcranial direct current stimulation can improve speech fluency in adults who stutter. We predicted that applying anodal stimulation to the left inferior frontal cortex during speech production with temporary fluency inducers would result in longer-lasting fluency improvements. Thirty male adults who stutter completed a randomized, double-blind, controlled trial of anodal transcranial direct current stimulation over left inferior frontal cortex. Fifteen participants received 20 min of 1-mA stimulation on five consecutive days while speech fluency was temporarily induced using choral and metronome-timed speech. The other 15 participants received the same speech fluency intervention with sham stimulation. Speech fluency during reading and conversation was assessed at baseline, before and after the stimulation on each day of the 5-day intervention, and at 1 and 6 weeks after the end of the intervention. Anodal stimulation combined with speech fluency training significantly reduced the percentage of disfluent speech measured 1 week after the intervention compared with fluency intervention alone. At 6 weeks after the intervention, this improvement was maintained during reading but not during conversation. Outcome scores at both post-intervention time points on a clinical assessment tool (the Stuttering Severity Instrument, version 4) also showed significant improvement in the group receiving

Analysis of passive systems as a tool for energy saving in buildings: solar control; Analisis de sistemas pasivos como herramienta para el ahorro de energia en edificaciones: Control solar

Energy Technology Data Exchange (ETDEWEB)

Saravia, Maricela; Morillon Galvez, David [Instituto de Ingenieria, UNAM, Mexico, D. F. (Mexico)

1999-07-01

A bioclimatic study of El Salvador is presented, with the purpose of using window eaves as elements of passive solar control and to determine the optimal angles of orientation, in order to diminish the thermal gains by direct solar radiation and to manage to get close to the comfort conditions. The former with the intention of integrating measures that help to obtain energy efficiency and comfortable buildings, for the conditions of warm humid climate, characteristic of a Central American country like El Salvador. Besides offering a document of consultation among the professionals dedicated to the design and as base of bioclimatic considerations that must have the construction regulations. As a conclusion the optimal angles of eaves for each orientation are presented and a quantitative estimation of the savings that would imply not to consume electrical energy in cooling systems using these elements as a protection to the direct solar radiation. [Spanish] Se presenta un estudio del bioclima de El Salvador, con el fin de utilizar aleros de ventana como elementos de control solar pasivo y determinar los angulos optimos por orientacion, para disminuir las ganancias termicas por radiacion solar directa y lograr acercar a las condiciones de confort. Lo anterior con el objeto de integrar medidas que coadyuven a lograr edificios energeticamente eficientes y confortables, para las condiciones de clima calido humedo, caracteristico de un pais centroamericano como El Salvador. Ademas de brindar un documento de consulta entre los profesionales dedicados al dise y como base de consideraciones bioclimaticas que debe tener el reglamento de construcciones. Como conclusion se presentan los angulos optimos de alero por cada orientacion y una estimacion cuantitativa del ahorro que implicaria el no consumir energia electrica en sistemas de enfriamiento utilizando estos elementos como una proteccion a la radiacion solar directa.

Development of an intelligent high-voltage direct-current power supply for nuclear detectors

International Nuclear Information System (INIS)

Zhao Xiuliang

1997-01-01

The operation and performances of a new type direct-current high-voltage power supply are described. The power supply with intelligent feature is controlled by a single-chip microcomputer (8031), and various kinds of output voltage can be preset. The output-voltage is monitored and regulated by the single-chip microcomputer and displayed by LED. The output voltage is stable when the load current is within the allowable limits

Energy saving program in an operating potable water and sanitation organism; Programa de ahorro de energia en un organismo operador de agua potable y saneamiento

Energy Technology Data Exchange (ETDEWEB)

Flores Cruz, Juan Jose [Fideicomiso para el Ahorro de la Energia Electrica, (Mexico)

2001-03-01

For the achievement of the objectives it was decided to use, among others, the following strategies: Personnel training, increase of the efficiency of the electromechanical equipment, study of Comision Federal de Electricidad (CFE) tariffs, correction of low power factors, increase of load factors, operation automate, regulation of the operation times, preventive maintenance of the equipment, establishment of technical standards, rational and efficient use of air conditioning equipment and illumination. So that these actions were applied in an easy and opportune form, it was established that within the structure of the General Coordination of Foreign Municipalities, the Program of Energy Saving depended directly of the Technical Management of CFE. In this way, the recommendations are first put under consideration of high-level officers, and then are lowered to the operative departments. [Spanish] Para el logro de los objetivos se acordo utilizar, entre otras, las siguientes estrategias: capacitacion del personal; aumentar la eficiencia de los equipos electromecanicos; estudio de tarifas de la Comision Federal de Electricidad (CFE); correccion de bajos factores de potencia; aumento de los factores de carga; automatizar la operacion; regular de los tiempos de operacion; mantenimiento preventivo a los equipos; establecimiento de normas tecnicas; uso racional y eficiente de aire acondicionado e iluminacion. Para que estas acciones se aplicaran en forma agil y oportuna, se establecio que dentro de la estructura de la Coordinacion General de Municipios Foraneos, el Programa de Ahorro de Energia dependiera directamente de la Gerencia Tecnica de la CRE. De esta forma, las recomendaciones primero se someten a consideracion de los funcionarios de alto nivel, y luego bajan a los departamentos operativos.

Current ethical and legal issues in health-related direct-to-consumer genetic testing.

Science.gov (United States)

Niemiec, Emilia; Kalokairinou, Louiza; Howard, Heidi Carmen

2017-09-01

A variety of health-related genetic testing is currently advertized directly to consumers. This article provides a timely overview of direct-to-consumer genetic testing (DTC GT) and salient ethical issues, as well as an analysis of the impact of the recently adopted regulation on in vitro diagnostic medical devices on DTC GT. DTC GT companies currently employ new testing approaches, report on a wide spectrum of conditions and target new groups of consumers. Such activities raise ethical issues including the questionable analytic and clinical validity of tests, the adequacy of informed consent, potentially misleading advertizing, testing in children, research uses and commercialization of genomic data. The recently adopted regulation on in vitro diagnostic medical devices may limit the offers of predisposition DTC GT in the EU market.

The effect of current flow direction on motor hot spot allocation by transcranial magnetic stimulation.

Science.gov (United States)

Stephani, Caspar; Paulus, Walter; Sommer, Martin

2016-01-01

The objective of this study was to investigate the significance of pulse configurations and current direction for corticospinal activation using transcranial magnetic stimulation (TMS). In 11 healthy subjects (8 female), a motor map for the motor evoked potentials (MEPs) recorded from the first dorsal interosseus (FDI), abductor digiti minimi (ADM), extensor carpi radialis, and biceps brachii (BB) muscles of the dominant side was established. Starting from a manually determined hot spot of the FDI representation, we measured MEPs at equal oriented points on an hexagonal grid, with 7 MEPs recorded at each point, using the following pulse configurations: posteriorly directed monophasic (Mo-P), anteriorly directed monophasic (Mo-A), biphasic with the more relevant second cycle oriented posteriorly (Bi-P) as well as a reversed biphasic condition (Bi-A). For each pulse configuration, a hot spot was determined and a center of gravity (CoG) was calculated. We found that the factor current direction had an effect on location of the CoG-adjusted hot spot in the cranio-caudal axis but not in the latero-medial direction with anteriorly directed pulses locating the CoG more anteriorly and vice versa. In addition, the CoG for the FDI was more laterally than the cortical representations for the abductor digiti minimi (ADM) and extensor carpi radialis (ECR) which were registered as well. The results indicate that direction of the current pulse should be taken into account for determination of the motor representation of a muscle by TMS. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Evaluation of energy saving in pilot projects of window type air conditioning equipment in the domestic sector; Evaluacion del ahorro de energia en proyectos pilotos en equipos de aire acondicionado tipo ventana en el sector domestico

Energy Technology Data Exchange (ETDEWEB)

Duran Ramirez, Ricardo [Comision Nacional para el Ahorro de Energia, Mexico, D.F. (Mexico)

2001-07-01

The present work shows the energy saving when replacing low efficiency window type air conditioning equipment, for higher efficiency equipment, as well as the necessary parameters to identify the results obtained by the pilot projects of substitution of conventional equipment for other more efficient in the domestic sector. [Spanish] El presente trabajo muestra los ahorros de energia al sustituir equipos de aire acondicionado tipo ventana de baja eficiencia, por equipos de mayor eficiencia, asi como los parametros necesarios para identificar los resultados obtenidos, por los proyectos pilotos de sustitucion de equipos convencionales por otros mas eficientes en el sector domestico.

Effect-directed analysis: Current status and future challenges

Science.gov (United States)

Hong, Seongjin; Giesy, John P.; Lee, Jung-Suk; Lee, Jong-Hyeon; Khim, Jong Seong

2016-09-01

Effect-directed analysis (EDA) has become useful for identification of toxicant(s) that occur in mixtures in the environment, especially those that are causative agents of specific adverse effects. Here, we summarize and review EDA methodology including preparation of samples, biological analyses, fractionations, and instrumental analyses, highlighting key scientific advancements. A total of 63 documents since 1999 (Scopus search) including 46 research articles, 13 review papers, and 4 project descriptions, have been collected and reviewed in this study. At the early stage (1999-2010), most studies that applied EDA focused on organic extracts of freshwater and coastal contaminated sediments and wastewater. Toxic effects were often measured using cell-based bioassays ( in vitro) and the causative chemicals were identified by use of low resolution gas chromatography with mass selective detector (GCMSD). More recently (2010-present), EDA has been extended to various matrices such as biota, soil, crude oil, and suspended solids and techniques have been improved to include determination of bioavailability in vivo. In particular, methods for non-target screenings of organic chemicals in environmental samples using cutting-edge instrumentation such as time of flight-mass spectrometry (ToF-MS), Fourier transform-ion cyclotron resonance (FT-ICR), and Orbitrap mass spectrometer have been developed. This overview provides descriptions of recent improvements of EDA and suggests future research directions based on current understandings and limitations.

Transcranial Direct Current Stimulation: Considerations for Research in Adolescent Depression

Directory of Open Access Journals (Sweden)

Jonathan C. Lee

2017-06-01

Full Text Available Adolescent depression is a prevalent disorder with substantial morbidity and mortality. Current treatment interventions do not target relevant pathophysiology and are frequently ineffective, thereby leading to a substantial burden for individuals, families, and society. During adolescence, the prefrontal cortex undergoes extensive structural and functional changes. Recent work suggests that frontolimbic development in depressed adolescents is delayed or aberrant. The judicious application of non-invasive brain stimulation techniques to the prefrontal cortex may present a promising opportunity for durable interventions in adolescent depression. Transcranial direct current stimulation (tDCS applies a low-intensity, continuous current that alters cortical excitability. While this modality does not elicit action potentials, it is thought to manipulate neuronal activity and neuroplasticity. Specifically, tDCS may modulate N-methyl-d-aspartate receptors and L-type voltage-gated calcium channels and effect changes through long-term potentiation or long-term depression-like mechanisms. This mini-review considers the neurobiological rationale for developing tDCS protocols in adolescent depression, reviews existing work in adult mood disorders, surveys the existing tDCS literature in adolescent populations, reviews safety studies, and discusses distinct ethical considerations in work with adolescents.

Effectiveness of direct-current cardioversion for treatment of supraventricular tachyarrhythmias, in particular atrial fibrillation, in surgical intensive care patients.

Science.gov (United States)

Mayr, Andreas; Ritsch, Nicole; Knotzer, Hans; Dünser, Martin; Schobersberger, Wolfgang; Ulmer, Hanno; Mutz, Norbert; Hasibeder, Walter

2003-02-01

To evaluate primary success rate and effectiveness of direct-current cardioversion in postoperative critically ill patients with new-onset supraventricular tachyarrhythmias. Prospective intervention study. Twelve-bed surgical intensive care unit in a university teaching hospital. Thirty-seven consecutive, adult surgical intensive care unit patients with new-onset supraventricular tachyarrhythmias without previous history of tachyarrhythmias. Direct-current cardioversion using a monophasic, damped sinus-wave defibrillator. Energy levels used were 50, 100, 200, and 300 J for regular supraventricular tachyarrhythmias (n = 6) and 100, 200, and 360 J for irregular supraventricular tachyarrhythmias (n = 31). None of the patients was hypoxic, hypokalemic, or hypomagnesemic at onset of supraventricular tachyarrhythmia. Direct-current cardioversion restored sinus rhythm in 13 of 37 patients (35% primary responders). Most patients responded to the first or second direct-current cardioversion shock. Only one of 25 patients requiring more than two direct-current cardioversion shocks converted into sinus rhythm. Primary responders were significantly younger and demonstrated significant differences in arterial Po2 values at onset of supraventricular tachyarrhythmias compared with nonresponders. At 24 and 48 hrs, only six (16%) and five (13.5%) patients remained in sinus rhythm, respectively. In contrast to recent literature, direct-current cardioversion proved to be an ineffective method for treatment of new-onset supraventricular tachyarrhythmias and, in particular, atrial fibrillation with a rapid ventricular response in surgical intensive care unit patients.

Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry.

Science.gov (United States)

Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P

2016-02-18

We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors.

A self-discharge model of Lithium-Sulfur batteries based on direct shuttle current measurement

DEFF Research Database (Denmark)

Knap, Vaclav; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

2016-01-01

. A simple but comprehensive mathematical model of the Li-S battery cell self-discharge based on the shuttle current was developed and is presented. The shuttle current values for the model parameterization were obtained from the direct shuttle current measurements. Furthermore, the battery cell depth......-of-discharge values were recomputed in order to account for the influence of the self-discharge and provide a higher accuracy of the model. Finally, the derived model was successfully validated against laboratory experiments at various conditions....

A method for crack profiles identification in eddy current testing by the multi-directional scan

International Nuclear Information System (INIS)

Kojima, Fumio; Ikeda, Takuya; Nguyen, Doung

2006-01-01

This paper is concerned with a method for identification of crack shape in conducting materials. Multi-directional scanning strategies using Eddy Current Testing is performed for sizing complex natural crackings. Two dimensional measurements by means of multi-directional scan are used in a output least square identifications. (author)

Effects of neglecting carrier tunneling on electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs

OpenAIRE

Hakim, MMA; Haque, A

2002-01-01

We investigate the validity of the assumption of neglecting carrier tunneling effects on self-consistent electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs. Comparison between simulated and experimental results shows that for accurate modeling of direct tunneling current, tunneling effects on potential profile need to be considered. The relative error in gate current due to neglecting carrier tunneling is higher at higher gate voltages and increases...

Direct current microhollow cathode discharges on silicon devices operating in argon and helium

Science.gov (United States)

Michaud, R.; Felix, V.; Stolz, A.; Aubry, O.; Lefaucheux, P.; Dzikowski, S.; Schulz-von der Gathen, V.; Overzet, L. J.; Dussart, R.

2018-02-01

Microhollow cathode discharges have been produced on silicon platforms using processes usually used for MEMS fabrication. Microreactors consist of 100 or 150 μm-diameter cavities made from Ni and SiO2 film layers deposited on a silicon substrate. They were studied in the direct current operating mode in two different geometries: planar and cavity configuration. Currents in the order of 1 mA could be injected in microdischarges operating in different gases such as argon and helium at a working pressure between 130 and 1000 mbar. When silicon was used as a cathode, the microdischarge operation was very unstable in both geometry configurations. Strong current spikes were produced and the microreactor lifetime was quite short. We evidenced the fast formation of blisters at the silicon surface which are responsible for the production of these high current pulses. EDX analysis showed that these blisters are filled with argon and indicate that an implantation mechanism is at the origin of this surface modification. Reversing the polarity of the microdischarge makes the discharge operate stably without current spikes, but the discharge appearance is quite different from the one obtained in direct polarity with the silicon cathode. By coating the silicon cathode with a 500 nm-thick nickel layer, the microdischarge becomes very stable with a much longer lifetime. No current spikes are observed and the cathode surface remains quite smooth compared to the one obtained without coating. Finally, arrays of 76 and 576 microdischarges were successfully ignited and studied in argon. At a working pressure of 130 mbar, all microdischarges are simultaneously ignited whereas they ignite one by one at higher pressure.

Current and Emerging Directions in the Treatment of Eating Disorders

Directory of Open Access Journals (Sweden)

Tiffany A. Brown

2012-01-01

Full Text Available Eating disorders are a significant source of psychiatric morbidity in young women and demonstrate high comorbidity with mood, anxiety, and substance use disorders. Thus, clinicians may encounter eating disorders in the context of treating other conditions. This review summarizes the efficacy of current and emerging treatments for anorexia nervosa (AN, bulimia nervosa (BN, and binge eating disorder (BED. Treatment trials were identified using electronic and manual searches and by reviewing abstracts from conference proceedings. Family based therapy has demonstrated superiority for adolescents with AN but no treatment has established superiority for adults. For BN, both 60 mg fluoxetine and cognitive behavioral therapy (CBT have well-established efficacy. For BED, selective serotonin reuptake inhibitors, CBT, and interpersonal psychotherapy have demonstrated efficacy. Emerging directions for AN include investigation of the antipsychotic olanzapine and several novel psychosocial treatments. Future directions for BN and BED include increasing CBT disseminability, targeting affect regulation, and individualized stepped-care approaches.

Counteracting fatigue in multiple sclerosis with right parietal anodal transcranial direct current stimulation

NARCIS (Netherlands)

Hanken, K.; Bosse, M.; Möhrke, K.; Eling, P.A.T.M.; Kastrup, A.; Antal, A.; Hildebrandt, H.

2016-01-01

Background: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time and errors with prolonged time-on-task. Objectives: The aim of this study was to investigate whether anodal transcranial direct current stimulation

On-Line Monitoring of Environment-Assisted Cracking in Nuclear Piping Using Array Probe Direct Current Potential Drop

OpenAIRE

Kim, Y.; Choi, S.; Yoon, J. Y.; Nam, W. C.; Hwang, I. S.; Bromberg, Leslie; Stahle, Peter W; Ballinger, Ronald G

2015-01-01

A direct current potential drop method utilizing array probes with measurement ends maintaining an equalized potential designated as equi-potential switching array probe direct current potential drop (ESAP-DCPD) technique has been developed earlier at Seoul National University. This paper validates ESAP-DCPD technique by showing consistency among experimental measurements, analytical solution and numerical predictions using finite element analysis (FEA) of electric field changes with crack gr...

Optical gain in colloidal quantum dots achieved with direct-current electrical pumping

Science.gov (United States)

Lim, Jaehoon; Park, Young-Shin; Klimov, Victor I.

2018-01-01

Chemically synthesized semiconductor quantum dots (QDs) can potentially enable solution-processable laser diodes with a wide range of operational wavelengths, yet demonstrations of lasing from the QDs are still at the laboratory stage. An important challenge--realization of lasing with electrical injection--remains unresolved, largely due to fast nonradiative Auger recombination of multicarrier states that represent gain-active species in the QDs. Here we present population inversion and optical gain in colloidal nanocrystals realized with direct-current electrical pumping. Using continuously graded QDs, we achieve a considerable suppression of Auger decay such that it can be outpaced by electrical injection. Further, we apply a special current-focusing device architecture, which allows us to produce high current densities (j) up to ~18 A cm-2 without damaging either the QDs or the injection layers. The quantitative analysis of electroluminescence and current-modulated transmission spectra indicates that with j = 3-4 A cm-2 we achieve the population inversion of the band-edge states.

A Comparison of Alternating Current and Direct Current Electrospray Ionization for Mass Spectrometry

Science.gov (United States)

Sarver, Scott A.; Chetwani, Nishant; Dovichi, Norman J.; Go, David B.; Gartner, Carlos A.

2014-04-01

A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS have been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were one to two orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50 %, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one-half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating that improvements in spectral quality may benefit certain compounds or classes of compounds, on an individual basis.

Comparative studies of high-frequency and direct current molecular gas discharges

International Nuclear Information System (INIS)

Goichman, V.H.; Goldfarb, V.M.; Tendler, M.B.

1975-01-01

Electron gas parameters, gas temperatures, ionization and thermal instability are found to be markedly different in direct current glow discharges from capactive electrodless high frequency discharge even when equal net power input is provided. It is reasonable to expect that the combined discharge containing both types of discharges mentioned above may be expected to improve significantly both the steady-state and transient characteristics of the plasma. The characteristics of different discharges in air, nitrogen air-CO 2 -He mixture have been compared. Because of the lack of the direct electrical methods for measurements of the hf plasma, exphasis in this investigation has been laid on both theoretical) based on the analytical expression for electron energy distribution function received previously and experimental spectroscopic evaluations of the plasma parameters. (Auth.)

Mapping geological structures in bedrock via large-scale direct current resistivity and time-domain induced polarization tomography

DEFF Research Database (Denmark)

Rossi, Matteo; Olsson, Per-Ivar; Johansson, Sara

2017-01-01

-current resistivity distribution of the subsoil and the phase of the complex conductivity using a constant-phase angle model. The joint interpretation of electrical resistivity and induced-polarization models leads to a better understanding of complex three-dimensional subsoil geometries. The results have been......An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has......, there are northwest-trending Permian dolerite dykes that are less deformed. Four 2D direct-current resistivity and time-domain induced-polarization profiles of about 1-km length have been carefully pre-processed to retrieve time-domain induced polarization responses and inverted to obtain the direct...

Online effects of transcranial direct current stimulation on prefrontal metabolites in gambling disorder.

Science.gov (United States)

Dickler, Maya; Lenglos, Christophe; Renauld, Emmanuelle; Ferland, Francine; Edden, Richard A; Leblond, Jean; Fecteau, Shirley

2018-03-15

Gambling disorder is characterized by persistent maladaptive gambling behaviors and is now considered among substance-related and addictive disorders. There is still unmet therapeutic need for these clinical populations, however recent advances indicate that interventions targeting the Glutamatergic/GABAergic system hold promise in reducing symptoms in substance-related and addictive disorders, including gambling disorder. There is some data indicating that transcranial direct current stimulation may hold clinical benefits in substance use disorders and modulate levels of brain metabolites including glutamate and GABA. The goal of the present work was to test whether this non-invasive neurostimulation method modulates key metabolites in gambling disorder. We conducted a sham-controlled, crossover, randomized study, blinded at two levels in order to characterize the effects of transcranial direct current stimulation over the dorsolateral prefrontal cortex on neural metabolites levels in sixteen patients with gambling disorder. Metabolite levels were measured with magnetic resonance spectroscopy from the right dorsolateral prefrontal cortex and the right striatum during active and sham stimulation. Active as compared to sham stimulation elevated prefrontal GABA levels. There were no significant changes between stimulation conditions in prefrontal glutamate + glutamine and N-acetyl Aspartate, or in striatal metabolite levels. Results also indicated positive correlations between metabolite levels during active, but not sham, stimulation and levels of risk taking, impulsivity and craving. Our findings suggest that transcranial direct current stimulation can modulate GABA levels in patients with gambling disorder which may represent an interesting future therapeutic avenue. Copyright © 2017 Elsevier Ltd. All rights reserved.

Energy saving by means of air conditioning equipment replacement and the household application of thermal insulation; Ahorro de energia electrica por reemplazo de equipos de aire acondicionado y aplicacion de aislamiento termico en viviendas

Energy Technology Data Exchange (ETDEWEB)

Peralta Solorio, Jose Luis [Fideicomiso para el Ahorro de la Energia (Mexico)

2005-07-15

An extension study of the Financing Program for Energy Saving looked for the evaluation of the electric energy saving potential obtained by the replacement of air conditioning equipment and the application of thermal insulation in 30 houses of two Mexican cities with warmth climate. In a joint effort with Comision Federal de Electricidad the consumption files of the users were analyzed and field measurements of electric demand and of refrigeration were made. As a following step the change of the refrigeration necessities derived from the application of thermal insulation were evaluated as well as the energy efficiency improvement obtained by the substitution of the air conditioning equipment and the favorable results obtained by the implementation of both measures - thermal insulation and change of air conditioning equipment in a joint form. This way, as a conclusion, the optimum sequence of application of these measures is revealed. [Spanish] Un estudio extension del Programa de Financiamiento para el Ahorro de Energia Electrica busco evaluar el potencial de ahorro de energia electrica alcanzado por el reemplazo de equipos de aire acondicionado y la aplicacion de aislamiento termico en 30 viviendas de dos ciudades mexicanas con clima calido. En un esfuerzo conjunto con la Comision Federal de Electricidad se analizaron los historiales de consumo de los usuarios y se efectuaron las mediciones de campo de demanda electrica y de refrigeracion. Como paso siguiente se valoro el cambio en las necesidades de refrigeracion derivado de la aplicacion de aislamiento termico al igual que la mejora en eficiencia energetica obtenida por la sustitucion de aire acondicionado y se identificaron los resultados favorecedores arrojados por la implementacion de ambas medidas -aislamiento termico y cambio de equipo de aire acondicionado- en forma conjunta. De esta manera, como conclusion, se devela la mas optima secuencia de aplicacion de estas medidas.

Early Childhood Inclusion in the United States: Goals, Current Status, and Future Directions

Science.gov (United States)

Guralnick, Michael J.; Bruder, Mary Beth

2016-01-01

The current status and future directions of early childhood inclusion in the United States are discussed from the perspective of 4 key goals: access, accommodations and feasibility, developmental progress, and social integration. Recommendations are put forward to promote inclusion goals emphasizing administrative structures, personnel…

Current in the plasma moving in an arbitrary direction across a magnetic field

International Nuclear Information System (INIS)

Samokhin, M.V.

1991-01-01

Condition under which freezing-in equation is satisfied in case of arbitrarily changeable direction of rate of plasma flow across the magnetic field is considered. It is shown that in the ideally frozen-in plasma there should exist current independent on the flow rate

Transcranial direct current stimulation in psychiatric disorders

Science.gov (United States)

Tortella, Gabriel; Casati, Roberta; Aparicio, Luana V M; Mantovani, Antonio; Senço, Natasha; D’Urso, Giordano; Brunelin, Jerome; Guarienti, Fabiana; Selingardi, Priscila Mara Lorencini; Muszkat, Débora; Junior, Bernardo de Sampaio Pereira; Valiengo, Leandro; Moffa, Adriano H; Simis, Marcel; Borrione, Lucas; Brunoni, André R

2015-01-01

The interest in non-invasive brain stimulation techniques is increasing in recent years. Among these techniques, transcranial direct current stimulation (tDCS) has been the subject of great interest among researchers because of its easiness to use, low cost, benign profile of side effects and encouraging results of research in the field. This interest has generated several studies and randomized clinical trials, particularly in psychiatry. In this review, we provide a summary of the development of the technique and its mechanism of action as well as a review of the methodological aspects of randomized clinical trials in psychiatry, including studies in affective disorders, schizophrenia, obsessive compulsive disorder, child psychiatry and substance use disorder. Finally, we provide an overview of tDCS use in cognitive enhancement as well as a discussion regarding its clinical use and regulatory and ethical issues. Although many promising results regarding tDCS efficacy were described, the total number of studies is still low, highlighting the need of further studies aiming to replicate these findings in larger samples as to provide a definite picture regarding tDCS efficacy in psychiatry. PMID:25815258

Characterizing Ductile Damage and Failure: Application of the Direct Current Potential Drop Method to Uncracked Tensile Specimens

OpenAIRE

Brinnel, V.; Döbereiner, B.; Münstermann, Sebastian

2014-01-01

Modern high-strength steels exhibit excellent ductility properties but their application is hindered by traditional design rules. A characterization of necessary safety margins for the ductile failure of these steels is therefore required. Direct observation of ductile damage within tests is currently not possible, only limited measurements can be made with synchrotron or X-ray radiation facilities. The direct current potential drop (DCPD) method can determine ductile crack propagation with l...

Modelo de gestión de crédito y cobranza para recuperar cartera vencida en la Cooperativa de ahorro y crédito San Miguel de Los Bancos y sus tres agencias que la integran

OpenAIRE

Armijos Loaiza, Alex David; Oña Muñoz, Julio César

2015-01-01

El presente trabajo de grado se elaboró con el fin de brindar una solución a la problemática que enfrenta la Cooperativa de Ahorro y Crédito San Miguel de los Bancos al momento de recuperar sus créditos emitidos a sus clientes, por lo tanto, se propuso modelo de gestión de crédito y cobranza para mejorar las deficiencias en los procesos que actualmente se llevan a cabo dentro área de crédito. Dentro del primer capítulo se hizo referencia a las fuentes bibliográficas y referenciales que permit...

Considering the influence of stimulation parameters on the effect of conventional and high-definition transcranial direct current stimulation.

Science.gov (United States)

To, Wing Ting; Hart, John; De Ridder, Dirk; Vanneste, Sven

2016-01-01

Recently, techniques to non-invasively modulate specific brain areas gained popularity in the form of transcranial direct current stimulation (tDCS) and high-definition transcranial direct current stimulation. These non-invasive techniques have already shown promising outcomes in various studies with healthy subjects as well as patient populations. Despite widespread dissemination of tDCS, there remain significant unknowns about the influence of a diverse number of tDCS parameters (e.g. polarity, size, position of electrodes & duration of stimulation) in inducing neurophysiological and behavioral effects. This article explores both techniques starting with the history of tDCS, to the differences between conventional tDCS and high-definition transcranial direct current stimulation, the underlying physiological mechanism, the (in)direct effects, the applications of tDCS with varying parameters, the efficacy, the safety issues and the opportunities for future research.

Comments on: “Transcranial Direct Current Stimulation for Obsessive-Compulsive Disorder: A Systematic Review”

Directory of Open Access Journals (Sweden)

Mohammad Alwardat

2018-03-01

Full Text Available Dear Editor, Brunelin et al. [1] recently conducted a systematic review that evaluated the effect of applied transcranial direct current stimulation (tDCS on patients with obsessive compulsive disorder (OCD.[...

Mechanisms and Effects of Transcranial Direct Current Stimulation

Science.gov (United States)

Giordano, James; Bikson, Marom; Kappenman, Emily S.; Clark, Vincent P.; Coslett, H. Branch; Hamblin, Michael R.; Hamilton, Roy; Jankord, Ryan; Kozumbo, Walter J.; McKinley, R. Andrew; Nitsche, Michael A.; Reilly, J. Patrick; Richardson, Jessica; Wurzman, Rachel

2017-01-01

The US Air Force Office of Scientific Research convened a meeting of researchers in the fields of neuroscience, psychology, engineering, and medicine to discuss most pressing issues facing ongoing research in the field of transcranial direct current stimulation (tDCS) and related techniques. In this study, we present opinions prepared by participants of the meeting, focusing on the most promising areas of research, immediate and future goals for the field, and the potential for hormesis theory to inform tDCS research. Scientific, medical, and ethical considerations support the ongoing testing of tDCS in healthy and clinical populations, provided best protocols are used to maximize safety. Notwithstanding the need for ongoing research, promising applications include enhancing vigilance/attention in healthy volunteers, which can accelerate training and support learning. Commonly, tDCS is used as an adjunct to training/rehabilitation tasks with the goal of leftward shift in the learning/treatment effect curves. Although trials are encouraging, elucidating the basic mechanisms of tDCS will accelerate validation and adoption. To this end, biomarkers (eg, clinical neuroimaging and findings from animal models) can support hypotheses linking neurobiological mechanisms and behavioral effects. Dosage can be optimized using computational models of current flow and understanding dose–response. Both biomarkers and dosimetry should guide individualized interventions with the goal of reducing variability. Insights from other applied energy domains, including ionizing radiation, transcranial magnetic stimulation, and low-level laser (light) therapy, can be prudently leveraged. PMID:28210202

Sensorless optimal sinusoidal brushless direct current for hard disk drives

Science.gov (United States)

Soh, C. S.; Bi, C.

2009-04-01

Initiated by the availability of digital signal processors and emergence of new applications, market demands for permanent magnet synchronous motors have been surging. As its back-emf is sinusoidal, the drive current should also be sinusoidal for reducing the torque ripple. However, in applications like hard disk drives, brushless direct current (BLDC) drive is adopted instead of sinusoidal drive for simplification. The adoption, however, comes at the expense of increased harmonics, losses, torque pulsations, and acoustics. In this paper, we propose a sensorless optimal sinusoidal BLDC drive. First and foremost, the derivation for an optimal sinusoidal drive is presented, and a power angle control scheme is proposed to achieve an optimal sinusoidal BLDC. The scheme maintains linear relationship between the motor speed and drive voltage. In an attempt to execute the sensorless drive, an innovative power angle measurement scheme is devised, which takes advantage of the freewheeling diodes and measures the power angle through the detection of diode voltage drops. The objectives as laid out will be presented and discussed in this paper, supported by derivations, simulations, and experimental results. The proposed scheme is straightforward, brings about the benefits of sensorless sinusoidal drive, negates the need for current sensors by utilizing the freewheeling diodes, and does not incur additional cost.

Safety and tolerability of transcranial direct current stimulation to stroke patients - A phase I current escalation study.

Science.gov (United States)

Chhatbar, Pratik Y; Chen, Rong; Deardorff, Rachael; Dellenbach, Blair; Kautz, Steven A; George, Mark S; Feng, Wuwei

A prior meta-analysis revealed that higher doses of transcranial direct current stimulation (tDCS) have a better post-stroke upper-extremity motor recovery. While this finding suggests that currents greater than the typically used 2 mA may be more efficacious, the safety and tolerability of higher currents have not been assessed in stroke patients. We aim to assess the safety and tolerability of single session of up to 4 mA in stroke patients. We adapted a traditional 3 + 3 study design with a current escalation schedule of 1»2»2.5»3»3.5»4 mA for this tDCS safety study. We administered one 30-min session of bihemispheric montage tDCS and simultaneous customary occupational therapy to patients with first-ever ischemic stroke. We assessed safety with pre-defined stopping rules and investigated tolerability through a questionnaire. Additionally, we monitored body resistance and skin temperature in real-time at the electrode contact site. Eighteen patients completed the study. The current was escalated to 4 mA without meeting the pre-defined stopping rules or causing any major safety concern. 50% of patients experienced transient skin redness without injury. No rise in temperature (range 26°C-35 °C) was noted and skin barrier function remained intact (i.e. body resistance >1 kΩ). Our phase I safety study supports that single session of bihemispheric tDCS with current up to 4 mA is safe and tolerable in stroke patients. A phase II study to further test the safety and preliminary efficacy with multi-session tDCS at 4 mA (as compared with lower current and sham stimulation) is a logical next step. ClinicalTrials.gov Identifier: NCT02763826. Copyright © 2017 Elsevier Inc. All rights reserved.

Measurements of the large-scale direct-current Earth potential and possible implications for the geomagnetic dynamo.

Science.gov (United States)

1985-07-05

The magnitude of the large-scale direct-current earth potential was measured on a section of a recently laid transatlantic telecommunications cable. Analysis of the data acquired on the 4476-kilometer cable yielded a mean direct-current potential drop of less than about 0.072 +/- 0.050 millivolts per kilometer. Interpreted in terms of a generation of the potential by the earth's geodynamo, such a small value of the mean potential implies that the toroidal and poloidal magnetic fields of the dynamo are approximately equal at the core-mantle boundary.

Current DOE direction in low-level waste management

International Nuclear Information System (INIS)

Wilhite, E.L.; Dolenc, M.R.; Shupe, M.W.; Waldo, L.C.

1989-01-01

The U.S. Department of Energy (DOE) is implementing revised DOE Order 5820.2A Radioactive Waste Management. Chapter III of the revised order provides prescriptive requirements for managing low-level waste and is the subject of this paper. The revised order requires that all DOE low-level radioactive and mixed waste be systematically managed, using an approach that considers the combination of waste management practices used in waste generation reduction, segregation, treatment, packaging, storage, and disposal. The Order defines performance objectives for protecting groundwater, for protecting against intrusion, and for maintaining adequate operational practices. A performance assessment will be required to ensure that waste management operations comply with these performance objectives. DOE implementation of the revised Order includes work in the areas of leach testing, waste stabilization, waste certification, facility monitoring, and management of unique waste streams. This paper summarizes the status of this work and the current direction DOE is taking in managing low-level waste under DOE 5820.2A

Molecular ultrasound imaging: current status and future directions

International Nuclear Information System (INIS)

Deshpande, N.; Needles, A.; Willmann, J.K.

2010-01-01

Targeted contrast-enhanced ultrasound (molecular ultrasound) is an emerging imaging strategy that combines ultrasound technology with novel molecularly-targeted ultrasound contrast agents for assessing biological processes at the molecular level. Molecular ultrasound contrast agents are nano- or micro-sized particles that are targeted to specific molecular markers by adding high-affinity binding ligands onto the surface of the particles. Following intravenous administration, these targeted ultrasound contrast agents accumulate at tissue sites overexpressing specific molecular markers, thereby enhancing the ultrasound imaging signal. High spatial and temporal resolution, real-time imaging, non-invasiveness, relatively low costs, lack of ionising irradiation and wide availability of ultrasound systems are advantages compared to other molecular imaging modalities. In this article we review current concepts and future directions of molecular ultrasound imaging, including different classes of molecular ultrasound contrast agents, ongoing technical developments of pre-clinical and clinical ultrasound systems, the potential of molecular ultrasound for imaging different diseases at the molecular level, and the translation of molecular ultrasound into the clinic.

Surface EEG-Transcranial Direct Current Stimulation (tDCS) Closed-Loop System.

Science.gov (United States)

Leite, Jorge; Morales-Quezada, Leon; Carvalho, Sandra; Thibaut, Aurore; Doruk, Deniz; Chen, Chiun-Fan; Schachter, Steven C; Rotenberg, Alexander; Fregni, Felipe

2017-09-01

Conventional transcranial direct current stimulation (tDCS) protocols rely on applying electrical current at a fixed intensity and duration without using surrogate markers to direct the interventions. This has led to some mixed results; especially because tDCS induced effects may vary depending on the ongoing level of brain activity. Therefore, the objective of this preliminary study was to assess the feasibility of an EEG-triggered tDCS system based on EEG online analysis of its frequency bands. Six healthy volunteers were randomized to participate in a double-blind sham-controlled crossover design to receive a single session of 10[Formula: see text]min 2[Formula: see text]mA cathodal and sham tDCS. tDCS trigger controller was based upon an algorithm designed to detect an increase in the relative beta power of more than 200%, accompanied by a decrease of 50% or more in the relative alpha power, based on baseline EEG recordings. EEG-tDCS closed-loop-system was able to detect the predefined EEG magnitude deviation and successfully triggered the stimulation in all participants. This preliminary study represents a proof-of-concept for the development of an EEG-tDCS closed-loop system in humans. We discuss and review here different methods of closed loop system that can be considered and potential clinical applications of such system.

Boosting Cognition : Effects of Multiple-Session Transcranial Direct Current Stimulation on Working Memory

NARCIS (Netherlands)

Talsma, L.J.; Kroese, H.A.; Slagter, H.A.

Transcranial direct current stimulation (tDCS) is a promising tool for neurocognitive enhancement. Several studies have shown that just a single session of tDCS over the left dorsolateral pFC (lDLPFC) can improve the core cognitive function of working memory (WM) in healthy adults. Yet, recent

Effects of transcranial direct current stimulation for treating depression: A modeling study

DEFF Research Database (Denmark)

Csifcsák, Gábor; Boayue, Nya Mehnwolo; Puonti, Oula

2018-01-01

Background: Transcranial direct current stimulation (tDCS) above the left dorsolateral prefrontal cortex (lDLPFC) has been widely used to improve symptoms of major depressive disorder (MDD). However, the effects of different stimulation protocols in the entire frontal lobe have not been investiga......Background: Transcranial direct current stimulation (tDCS) above the left dorsolateral prefrontal cortex (lDLPFC) has been widely used to improve symptoms of major depressive disorder (MDD). However, the effects of different stimulation protocols in the entire frontal lobe have not been...... regions. We evaluated effects of seven bipolar and two multi-electrode 4 × 1 tDCS protocols. Results: For bipolar montages, EFs were of comparable strength in the lDLPFC and in the medial prefrontal cortex (MPFC). Depending on stimulation parameters, EF cortical maps varied to a considerable degree......, but were found to be similar in controls and patients. 4 × 1 montages produced more localized, albeit weaker effects. Limitations: White matter anisotropy was not modeled. The relationship between EF strength and clinical response to tDCS could not be evaluated. Conclusions: In addition to l...

Direct current stimulation of the left temporoparietal junction modulates dynamic humor appreciation.

Science.gov (United States)

Slaby, Isabella; Holmes, Amanda; Moran, Joseph M; Eddy, Marianna D; Mahoney, Caroline R; Taylor, Holly A; Brunyé, Tad T

2015-11-11

The aim of this study was to evaluate the influence of transcranial direct current stimulation targeting the left temporoparietal junction (TPJ) on humor appreciation during a dynamic video rating task. In a within-participants design, we targeted the left TPJ with anodal, cathodal, or no transcranial direct current stimulation, centered at electrode site C3 using a 4×1 targeted stimulation montage. During stimulation, participants dynamically rated a series of six stand-up comedy videos for perceived humor. We measured event-related (time-locked to crowd laughter) modulation of humor ratings as a function of stimulation condition. Results showed decreases in rated humor during anodal (vs. cathodal or none) stimulation; this pattern was evident for the majority of videos and was only partially predicted by individual differences in humor style. We discuss the possibility that upregulation of neural circuits involved in the theory of mind and empathizing with others may reduce appreciation of aggressive humor. In conclusion, the present data show that neuromodulation of the TPJ can alter the mental processes underlying humor appreciation, suggesting critical involvement of this cortical region in detecting, comprehending, and appreciating humor.

Psychological Therapies for Auditory Hallucinations (Voices): Current Status and Key Directions for Future Research

NARCIS (Netherlands)

Thomas, N.; Hayward, M.; Peters, E; van der Gaag, M.; Bentall, R.P.; Jenner, J.; Strauss, C.; Sommer, I.E.; Johns, L.C.; Varese, F.; Gracia-Montes, J.M.; Waters, F.; Dodgson, G.; McCarthy-Jones, S.

2014-01-01

This report from the International Consortium on Hallucinations Research considers the current status and future directions in research on psychological therapies targeting auditory hallucinations (hearing voices). Therapy approaches have evolved from behavioral and coping-focused interventions,

Self-deformation in a direct current driven helium jet micro discharge

International Nuclear Information System (INIS)

Xu, S. F.; Zhong, X. X.

2016-01-01

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode

Hybrid indirect/direct contactor for thermal management of counter-current processes

Science.gov (United States)

Hornbostel, Marc D.; Krishnan, Gopala N.; Sanjurjo, Angel

2018-03-20

The invention relates to contactors suitable for use, for example, in manufacturing and chemical refinement processes. In an aspect is a hybrid indirect/direct contactor for thermal management of counter-current processes, the contactor comprising a vertical reactor column, an array of interconnected heat transfer tubes within the reactor column, and a plurality of stream path diverters, wherein the tubes and diverters are configured to block all straight-line paths from the top to bottom ends of the reactor column.

Self-deformation in a direct current driven helium jet micro discharge

Energy Technology Data Exchange (ETDEWEB)

Xu, S. F.; Zhong, X. X., E-mail: xxzhong@sjtu.edu.cn [State Key Laboratory of Advanced Optical Communication Systems and Networks and Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

2016-01-15

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

Self-deformation in a direct current driven helium jet micro discharge

Science.gov (United States)

Xu, S. F.; Zhong, X. X.

2016-01-01

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

In-vivo Imaging of Magnetic Fields Induced by Transcranial Direct Current Stimulation (tDCS) in Human Brain using MRI

Science.gov (United States)

Jog, Mayank V.; Smith, Robert X.; Jann, Kay; Dunn, Walter; Lafon, Belen; Truong, Dennis; Wu, Allan; Parra, Lucas; Bikson, Marom; Wang, Danny J. J.

2016-10-01

Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation technique that applies mA currents at the scalp to modulate cortical excitability. Here, we present a novel magnetic resonance imaging (MRI) technique, which detects magnetic fields induced by tDCS currents. This technique is based on Ampere’s law and exploits the linear relationship between direct current and induced magnetic fields. Following validation on a phantom with a known path of electric current and induced magnetic field, the proposed MRI technique was applied to a human limb (to demonstrate in-vivo feasibility using simple biological tissue) and human heads (to demonstrate feasibility in standard tDCS applications). The results show that the proposed technique detects tDCS induced magnetic fields as small as a nanotesla at millimeter spatial resolution. Through measurements of magnetic fields linearly proportional to the applied tDCS current, our approach opens a new avenue for direct in-vivo visualization of tDCS target engagement.

Diseño e implementación de un modelo de gestión administrativo para la cooperativa de ahorro y crédito educadores de Chimborazo Ltda., y su incidencia en los indicadores de gestión. Periodo marzo 2013-abril 2014.

OpenAIRE

Castillo Fiallos, Mariela Paulina

2015-01-01

El presente trabajo de investigación se realizó en la Cooperativa de Ahorro y Crédito Educadores de Chimborazo Ltda., de la Ciudad de Riobamba, Provincia de Chimborazo, ubicada en las calles Veloz 22-11 y Espejo (esquina), con el propósito de dotar a la Institución de una herramienta idónea, capaz de analizar la gestión administrativa de manera cuantitativa y cualitativa. La gestión administrativa, es una herramienta que brindara parámetros para facilitar la toma de decisiones mejorando...

Direct Reconstruction of Two-Dimensional Currents in Thin Films from Magnetic-Field Measurements

Science.gov (United States)

Meltzer, Alexander Y.; Levin, Eitan; Zeldov, Eli

2017-12-01

An accurate determination of microscopic transport and magnetization currents is of central importance for the study of the electric properties of low-dimensional materials and interfaces, of superconducting thin films, and of electronic devices. Current distribution is usually derived from the measurement of the perpendicular component of the magnetic field above the surface of the sample, followed by numerical inversion of the Biot-Savart law. The inversion is commonly obtained by deriving the current stream function g , which is then differentiated in order to obtain the current distribution. However, this two-step procedure requires filtering at each step and, as a result, oversmooths the solution. To avoid this oversmoothing, we develop a direct procedure for inversion of the magnetic field that avoids use of the stream function. This approach provides enhanced accuracy of current reconstruction over a wide range of noise levels. We further introduce a reflection procedure that allows for the reconstruction of currents that cross the boundaries of the measurement window. The effectiveness of our approach is demonstrated by several numerical examples.

Transcranial direct current stimulation may modulate extinction memory in posttraumatic stress disorder

OpenAIRE

van?t Wout, Mascha; Longo, Sharon M.; Reddy, Madhavi K.; Philip, Noah S.; Bowker, Marguerite T.; Greenberg, Benjamin D.

2017-01-01

Abstract Background Abnormalities in fear extinction and recall are core components of posttraumatic stress disorder (PTSD). Data from animal and human studies point to a role of the ventromedial prefrontal cortex (vmPFC) in extinction learning and subsequent retention of extinction memories. Given the increasing interest in developing noninvasive brain stimulation protocols for psychopathology treatment, we piloted whether transcranial direct current stimulation (tDCS) during extinction lear...

Energy saving by the use of polystyrene in construction; Ahorro de energia por la utilizacion de poliestireno en la construccion

Energy Technology Data Exchange (ETDEWEB)

Pimentel, Raul [Polioles S. A. de C. V., Mexico, D. F. (Mexico)

1993-12-31

In the past last years, the building industry has been faced with requirements in the rational energy use and environmental preservation. The polystyrene foam is a material that for more than forty years has demonstrated its attributes all over the world in its application in the construction industry as well as in the packing and crating industries, becoming a synonym of economic construction in regard to energy saving and a synonym also of a rational and safe packing. In this paper a short description is made of the manufacturing process of the expandable polystyrene foam, its properties and applications in the construction industry. [Espanol] En los ultimos anos, la industria de la construccion se ha enfrentado a exigencias en el uso racional de la energia y en la preservacion del medio ambiente. La espuma de poliestireno expansible es un material que por mas de cuarenta anos, ha demostrado sus cualidades a nivel mundial en su aplicacion tanto en la industria de la construccion como en la del empaque y embalaje, llegando a convertirse en sinonimo de una construccion economica en cuanto a ahorro de energia y sinonimo tambien de un embalaje racional y seguro. En este trabajo se hace una breve descripcion del proceso de fabricacion de la espuma de poliestireno expandible, sus propiedades y aplicaciones dentro de la industria de la construccion.

Energy saving by the use of polystyrene in construction; Ahorro de energia por la utilizacion de poliestireno en la construccion

Energy Technology Data Exchange (ETDEWEB)

Pimentel, Raul [Polioles S. A. de C. V., Mexico, D. F. (Mexico)

1992-12-31

In the past last years, the building industry has been faced with requirements in the rational energy use and environmental preservation. The polystyrene foam is a material that for more than forty years has demonstrated its attributes all over the world in its application in the construction industry as well as in the packing and crating industries, becoming a synonym of economic construction in regard to energy saving and a synonym also of a rational and safe packing. In this paper a short description is made of the manufacturing process of the expandable polystyrene foam, its properties and applications in the construction industry. [Espanol] En los ultimos anos, la industria de la construccion se ha enfrentado a exigencias en el uso racional de la energia y en la preservacion del medio ambiente. La espuma de poliestireno expansible es un material que por mas de cuarenta anos, ha demostrado sus cualidades a nivel mundial en su aplicacion tanto en la industria de la construccion como en la del empaque y embalaje, llegando a convertirse en sinonimo de una construccion economica en cuanto a ahorro de energia y sinonimo tambien de un embalaje racional y seguro. En este trabajo se hace una breve descripcion del proceso de fabricacion de la espuma de poliestireno expandible, sus propiedades y aplicaciones dentro de la industria de la construccion.

Development of a Direct Methanol Fuel Cell with Lightweight Disc Type Current Collectors

Directory of Open Access Journals (Sweden)

Yean-Der Kuan

2014-05-01

Full Text Available The direct methanol fuel cell (DMFC adopts methanol solution as a fuel suitable for low power portable applications. A miniature, lightweight, passive air-breathing design is therefore desired. This paper presents a novel planar disc-type DMFC with multiple cells containing a novel developed lightweight current collector at both the anode and cathode sides. The present lightweight current collector adopts FR4 Glass/Epoxy as the substrate with the current collecting areas located at the corresponding membrane electrolyte assembly (MEA areas. The current collecting areas are fabricated by sequentially coating a corrosion resistant layer and electrical conduction layer via the thermal evaporation technique. The anode current collector has carved flow channels for fuel transport and production. The cathode current collector has drilled holes for passive air breathing. In order to ensure feasibility in the present concept a 3-cell prototype DMFC module with lightweight disc type current collectors is designed and constructed. Experiments were conducted to measure the cell performance. The results show that the highest cell power output is 54.88 mW·cm−2 and successfully demonstrate the feasibility of this novel design.

Joint Inversion of Direct Current Resistivity and Seismic Refraction Data

International Nuclear Information System (INIS)

Kurt, B.B.

2007-01-01

In this study, I assumed the underground consist of horizontal layers. I developed one-dimensional (1D) Direct Current Resistivity (DCR) and seismic refraction inversion code using MATLAB package and attempt to find velocity, resistivity and depth of the layers. The code uses damped least square technique. The code can do inversion on DCR and seismic data either individually or jointly. I tested the joint inversion code on synthetic data. Eventually, I saw that the result of joint inversion is better than the result of individual inversions. The joint inversion found depth of models of each layer and, in addition, velocity and resistivity closer to real values

Improving CANDU annunciation - Current R and D and future directions

International Nuclear Information System (INIS)

Lupton, L.R.; Feher, M.P.; Davey, E.C.; Guo, K.Q.; Bhuiyan, S.H.

1994-01-01

Annunciation is used to ensure that control room staff are promptly alerted to important changes in plant conditions that may impact on safety and production goals. We are carrying out research and development to improve CANDU annunciation, in partnership with Canadian CANDU utility and design organizations. The main goal is to solve the ''information overload'' problem that occurs during major plant upsets, while providing operators with annunciation information needed to prevent, mitigate, and accommodate plant disturbances. To data, a set of annunciation concepts has been developed based on operational needs in a complex supervisory control environment. A prototype annunciation system has been developed and demonstrated with Point Lepreau Generating Station operations staff. Preliminary evaluations show that the system has the potential to solve many of the current problems associated with upset management. Further evaluation of this system is planned for 1994/95. This paper summarizes the project, including the current status, lessons learned to data, future directions of the research, and implementation by plants. (author). 9 refs, 3 figs, 1 tab

The technical-economic potential of thermal energy saving in hospitals; El potencial tecnico-economico de ahorro de energia termica en hospitales

Energy Technology Data Exchange (ETDEWEB)

Herrera, A. [Universidad Nacional Autonoma de Mexico (Mexico); Islas, J [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Arriola, A. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2001-07-01

cantidad representa un porcentaje importante de los gastos totales del hospital (29.367 millones de dolares) es importante determinar posibilidades tecnico - economicas de ahorro de energia termica del hospital. El HGZ N 1 - IMSS Ags. Esta ubicado en un conjunto mas amplio en donde se localizan las unidades del IMSS, tales como, la lavanderia regional, la unidad deportiva, el centro de seguridad social, la unidad de medicina familiar N 1 y el hospital. Sin embargo a partir de las instalaciones electricas y de suministro de vapor y agua caliente del hospital se distribuyen los fluidos electricos y termicos de todo este conjunto. Debido a esta situacion, en este trabajo nos referiremos al consumo global del conjunto del IMSS de Aguascalientes en donde el hospital es el principal consumidor de energia termica. En el presente trabajo calcularemos el potencial tecnico - economico de ahorro de energia termica del conjunto del IMSS a traves de la tecnica termodinamica de punto de pliegue o tecnica pinch.

Experimental Investigation of a Direct Methanol Fuel Cell with Hilbert Fractal Current Collectors

Directory of Open Access Journals (Sweden)

Jing-Yi Chang

2014-01-01

Full Text Available The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of 2×2, 4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

Energy saving in the house of social interest by means of the application of the power efficiency standard:NOM-020; Ahorro de energia en la vivienda de interes social mediante la aplicacion de la norma de eficiencia energetica: NOM-020

Energy Technology Data Exchange (ETDEWEB)

Diaz Jimenez, Rodolfo; Morillon Galvez, David [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

2001-07-01

In face of the urgent necessity of saving and of using in an efficient way the energy, the Secretariat of Energy (Sener) through the Comision Nacional para el Ahorro de Energia, (CONAE) (National Commission for Energy Saving) has promoted the design and application of different measures and programs of energy efficiency. The elaboration of standards of energy efficiency has been a subject of great importance to foment the adequate use of the energy resources. For the residential sector the standard first draft exists: NOM-020-ENER-1998 energy efficiency in constructions: Standard for the covering of buildings for housing up to three floors. In this study the thermal analysis of the cover of one of the house models more used in the construction of houses of social interest in Mexico. By applying the methodology proposed by the first draft of the Standard the thermal gains by conduction in roof and walls, and by radiation in windows were determined. The analysis was performed for several cities of the country with different climates, the results were compared with the values proposed in the Standard, the viability of application of this Standard in the sector of the house of social interest was analyzed and finally the energy saving in ceasing using air conditioning systems for interiors. [Spanish] Ante la imperiosa necesidad de ahorrar y usar de forma eficiente la energia, la Secretaria de Energia (Sener) a traves de la Comision Nacional para el Ahorro de Energia, (CONAE) ha promovido el diseno y aplicacion de diferentes medidas y programas de eficiencia energetica. La elaboracion de normas de eficiencia energetica ha sido un rubro de gran importancia para fomentar el uso adecuado de los recursos energeticos. Para el sector residencial existe el anteproyecto de norma: NOM-020-ENER-1998 ficiencia energetica en edificaciones: Norma para la envolvente de los edificios para uso habitacional hasta de tres pisos. En este estudio se presenta el analisis termico de la

Resistivity measurements using a direct current induction method (1963)

International Nuclear Information System (INIS)

Delaplace, J.; Hillairet, J.

1964-01-01

The conventional methods for measuring electrical resistivities necessitate the fixing of electrical contacts on the sample either mechanically or by soldering. Furthermore it is also necessary to carry,out the measurements on low cross-section samples which are not always easy to obtain. Our direct-current induction method on the other hand requires no contacts and can easily be applied to samples of large cross-section. The sample is placed in a uniform magnetic field; at the moment when the current is cut, eddy currents appear in the sample which tend to oppose the disappearance of the field. The way in which the magnetic flux decreases in the sample makes it possible to determine the resistivity of the material. This method has been applied to samples having diameters of between 1 and 30 mm in the case of metals which are good conductors. It gives a value for the local resistivity and makes it possible to detect any variation along a sample. The measurements can be carried out at all temperature from a few degrees absolute to 500 deg. C. We have used the induction method to follow the purification of beryllium by zone-melting; it is in effect possible to estimate the purity of a material by resistivity measurements. We have measured the resistivity along each bar treated by the zone-melting technique and have thus, localised the purest section. High temperature measurements have been carried out on uranium carbide and on iron-aluminium alloys. This method constitutes an interesting means of investigation the resistivity of solid materials. Its accuracy and rapidity make it particularly adapted both to fundamental research and to production control. (authors) [fr

Electrochemical deposition and characterization of zinc–nickel alloys deposited by direct and reverse current

Directory of Open Access Journals (Sweden)

JELENA B. BAJAT

2005-12-01

Full Text Available Zn–Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn–Ni alloys during exposure to a corrosive agent (3 % NaCl solution. It was shown that the Zn–Ni alloy electrodeposited by reverse current with a full period T = 1 s and r = 0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.

Opportunities for energy conservation detected in a diagnosis made for the smelting industry; Oportunidades de ahorro de energia detectadas en un diagnostico efectuado en la industria de la fundicion

Energy Technology Data Exchange (ETDEWEB)

Ramirez Bautista, Rolando; Magana Castro, Rogelio [Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE), Mexico, D. F. (Mexico)

1994-12-31

The smelting industry is one of the main industrial branches in the utilization of electric power at national level, for this reason an energy diagnosis was made in representative industries of this process in which excellent results were obtained regarding opportunity areas, with potentials ranging from 15% up to 40% of energy saving in relation to the energy consumption, with actions recoverable in less than 15 months. [Espanol] La industria de la fundicion es una de las principales ramas industriales en la utilizacion de la energia electrica a nivel nacional, por esta razon se realizo un diagnostico energetico en empresas representativas de este proceso y en las cuales se obtuvieron excelentes resultados en cuanto a areas de oportunidad, teniendo potenciales que van desde un 15% hasta un 40% de ahorro con relacion al consumo de energia, con medidas que se recuperan en menos de 15 meses.

Opportunities for energy conservation detected in a diagnosis made for the smelting industry; Oportunidades de ahorro de energia detectadas en un diagnostico efectuado en la industria de la fundicion

Energy Technology Data Exchange (ETDEWEB)

Ramirez Bautista, Rolando; Magana Castro, Rogelio [Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE), Mexico, D. F. (Mexico)

1993-12-31

The smelting industry is one of the main industrial branches in the utilization of electric power at national level, for this reason an energy diagnosis was made in representative industries of this process in which excellent results were obtained regarding opportunity areas, with potentials ranging from 15% up to 40% of energy saving in relation to the energy consumption, with actions recoverable in less than 15 months. [Espanol] La industria de la fundicion es una de las principales ramas industriales en la utilizacion de la energia electrica a nivel nacional, por esta razon se realizo un diagnostico energetico en empresas representativas de este proceso y en las cuales se obtuvieron excelentes resultados en cuanto a areas de oportunidad, teniendo potenciales que van desde un 15% hasta un 40% de ahorro con relacion al consumo de energia, con medidas que se recuperan en menos de 15 meses.

Direct current plasma jet at atmospheric pressure operating in nitrogen and air

Science.gov (United States)

Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

2013-01-01

An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

Hybrid Direct-Current Circuit Breaker

Science.gov (United States)

Wang, Ruxi (Inventor); Premerlani, William James (Inventor); Caiafa, Antonio (Inventor); Pan, Yan (Inventor)

2017-01-01

A circuit breaking system includes a first branch including at least one solid-state snubber; a second branch coupled in parallel to the first branch and including a superconductor and a cryogenic contactor coupled in series; and a controller operatively coupled to the at least one solid-state snubber and the cryogenic contactor and programmed to, when a fault occurs in the load circuit, activate the at least one solid-state snubber for migrating flow of the electrical current from the second branch to the first branch, and, when the fault is cleared in the load circuit, activate the cryogenic contactor for migrating the flow of the electrical current from the first branch to the second branch.

A clinical trial with combined transcranial direct current stimulation and alcohol approach bias retraining

NARCIS (Netherlands)

den Uyl, T.E.; Gladwin, T.E.; Rinck, M.; Lindenmeyer, J.; Wiers, R.W.

2017-01-01

Two studies showed an improvement in clinical outcomes after alcohol approach bias retraining, a form of Cognitive Bias Modification (CBM). We investigated whether transcranial direct current stimulation (tDCS) could enhance effects of CBM. TDCS is a neuromodulation technique that can increase

Program of actions for energy conservation in the equipment for the urban public transportation; Programa de acciones para el ahorro de la energia en los equipos de transporte publico urbanos

Energy Technology Data Exchange (ETDEWEB)

Sanhez Arellano, L.I. [Facultad de Ingenieria, Universidad Autonoma del Estado de Mexico, Toluca (Mexico)

1995-12-31

las redes de transporte y su explotacion, asi como la del ahorro y uso eficiente de la energia utilizada para su funcionamiento. El trabajo aqui presentado se inscribe dentro de las lineas de interes de este programa. Las caracteristicas propias de operacion y de consumo de energia de los diferentes tipos de vehiculos utilizados en el servicio de transporte publico urbano, dependen principalmente de las aplicaciones para las que se hayan previsto. Sin embargo un punto importante es el conocer de manera mas concreta y especifica la naturaleza y otras opciones de utilizacion posibles de los diversos sistemas de transporte urbano, asi como su impacto energetico y la posibilidad de ahorros bien canalizados. El objetivo de este trabajo es la de presentar de manera concreta los diferentes equipos utilizados en el transporte publico urbano, haciendo una comparacion energetica, ademas de plantear un programa de acciones tendientes al ahorro de energia para los vehiculos que operan actualmente en las principales ciudades del pais. Se indican las principales acciones y sus caracteristicas basicas para su puesta en marcha, las cuales se pueden resumir en tres grandes rubros: -acciones dentro de las mismas empresas y sobre el parque vehicular existente. -acciones sobre la administracion y explotacion de los sistemas de transporte. -acciones para la utilizacion de nuevos equipos y vehiculos mas eficientes. Una explicacion detallada de cada una de estas acciones y su impacto en el consumo de energeticos son el proposito final de este estudio.

Program of actions for energy conservation in the equipment for the urban public transportation; Programa de acciones para el ahorro de la energia en los equipos de transporte publico urbanos

Energy Technology Data Exchange (ETDEWEB)

Sanhez Arellano, L I [Facultad de Ingenieria, Universidad Autonoma del Estado de Mexico, Toluca (Mexico)

1996-12-31

las redes de transporte y su explotacion, asi como la del ahorro y uso eficiente de la energia utilizada para su funcionamiento. El trabajo aqui presentado se inscribe dentro de las lineas de interes de este programa. Las caracteristicas propias de operacion y de consumo de energia de los diferentes tipos de vehiculos utilizados en el servicio de transporte publico urbano, dependen principalmente de las aplicaciones para las que se hayan previsto. Sin embargo un punto importante es el conocer de manera mas concreta y especifica la naturaleza y otras opciones de utilizacion posibles de los diversos sistemas de transporte urbano, asi como su impacto energetico y la posibilidad de ahorros bien canalizados. El objetivo de este trabajo es la de presentar de manera concreta los diferentes equipos utilizados en el transporte publico urbano, haciendo una comparacion energetica, ademas de plantear un programa de acciones tendientes al ahorro de energia para los vehiculos que operan actualmente en las principales ciudades del pais. Se indican las principales acciones y sus caracteristicas basicas para su puesta en marcha, las cuales se pueden resumir en tres grandes rubros: -acciones dentro de las mismas empresas y sobre el parque vehicular existente. -acciones sobre la administracion y explotacion de los sistemas de transporte. -acciones para la utilizacion de nuevos equipos y vehiculos mas eficientes. Una explicacion detallada de cada una de estas acciones y su impacto en el consumo de energeticos son el proposito final de este estudio.

Visualizing Transcranial Direct Current Stimulation (tDCS) in vivo using Magnetic Resonance Imaging

Science.gov (United States)

Jog, Mayank Anant

Transcranial Direct Current Stimulation (tDCS) is a low-cost, non-invasive neuromodulation technique that has been shown to treat clinical symptoms as well as improve cognition. However, no techniques exist at the time of research to visualize tDCS currents in vivo. This dissertation presents the theoretical framework and experimental implementations of a novel MRI technique that enables non-invasive visualization of the tDCS electric current using magnetic field mapping. The first chapter establishes the feasibility of measuring magnetic fields induced by tDCS currents. The following chapter discusses the state of the art implementation that can measure magnetic field changes in individual subjects undergoing concurrent tDCS/MRI. The final chapter discusses how the developed technique was integrated with BOLD fMRI-an established MRI technique for measuring brain function. By enabling a concurrent measurement of the tDCS current induced magnetic field as well as the brain's hemodynamic response to tDCS, our technique opens a new avenue to investigate tDCS mechanisms and improve targeting.

Statistical mechanical characteristics of slip-ring induction motors when direct current braking

Energy Technology Data Exchange (ETDEWEB)

Kedzior, W; Muchorowski, J; Pienkowski, K

1980-09-01

This paper evaluates methods of braking high capacity belt conveyors used in brown coal surface mines in Poland. Complications associated with belt conveyor braking, particularly when a conveyor moves down a slope, are analyzed. A method of calculating mechanical characteristics of wound-rotor induction motors during direct current braking taking into account saturation of magnetic circuit is presented. Characteristics of the SZUr motor with 630 kW power, used in brown coal mining, are also given. Analyses show that motor operation can be efficiently braked in two ways: 1. by changing additional resistance in rotor circuit (e.g. using thyristor controller); 2. by changing intensity of electric current supplied to stator winding (e.g. using a rectifier). (3 refs.) (In Polish)

Transcranial direct current stimulation in patients with Alzheimer’s disease: Challenges and responses

Directory of Open Access Journals (Sweden)

Hong Yuan

2015-09-01

Full Text Available The use of transcranial direct current stimulation (tDCS as a noninvasive therapeutic approach for Alzheimer’s disease (AD has gained increasing attention. Research regarding the utility of tDCS in AD is inconsistent. In this study, we reviewed the importance of individual diversity among AD patients, starting from the uninformative mean results. We also demonstrated variation among AD patients. Highly educated patients seem to benefit more; education also seems to modulate baseline measurements and the results. Individual cortical morphology also affects the current distribution, which influences the effectiveness of stimulation. We suggest the use of structural MRI to distinguish inter-individual variability; high-resolution modeling can also be used to predict current distributions and should be combined with cognitive training (CT along with tDCS.

Improving Naming Abilities among Healthy Young-Old Adults Using Transcranial Direct Current Stimulation

Science.gov (United States)

Lifshitz-Ben-Basat, Adi; Mashal, Nira

2018-01-01

Transcranial direct current stimulation (tDCS) is a noninvasive tool to facilitate brain plasticity and enhance language abilities. Our study aims to search for a potential beneficial influence of tDCS on a cognitive linguistic task of naming which found to decline during aging. A group of fifteen healthy old adults (M = 64.93 ± 5.09 years) were…

Effect of Cathodal Transcranial Direct Current Stimulation on a Child with Involuntary Movement after Hypoxic Encephalopathy

Directory of Open Access Journals (Sweden)

Mayumi Nagai

2018-01-01

Full Text Available The aim of the study was to investigate the effect of cathodal transcranial direct current stimulation to the supplementary motor area to inhibit involuntary movements of a child. An 8-year-old boy who developed hypoxic encephalopathy after asphyxia at the age of 2 had difficulty in remaining standing without support because of involuntary movements. He was instructed to remain standing with his plastic ankle-foot orthosis for 10 s at three time points by leaning forward with his forearms on a desk. He received cathodal or sham transcranial direct current stimulation to the supplementary motor area at 1 mA for 10 min. Involuntary movements during standing were measured using an accelerometer attached to his forehead. The low-frequency power of involuntary movements during cathodal transcranial direct current stimulation significantly decreased compared with that during sham stimulation. No adverse effects were observed. Involuntary movement reduction by cathodal stimulation to supplementary motor areas suggests that stimulations modulated the corticobasal ganglia motor circuit. Cathodal stimulation to supplementary motor areas may be effective for reducing involuntary movements and may be safely applied to children with movement disorders.

Current direction, temperature, and salinity data from moored current meter casts in the North Pacific Ocean from 1983-06-01 to 1983-08-01 (NODC Accession 8500147)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, temperature, and salinity data were collected using moored current meter casts in the North Pacific Ocean from June 1, 1983 to August 1, 1983....

Diseño de la propuesta del modelo de procesos para la unidad de desarrollo de software del área de servicios informáticos y redes de comunicación de la Cooperativa de ahorro y crédito Jardín Azuayo

OpenAIRE

Montero Arévalo, María Eugenia

2012-01-01

La aplicación de modelos de procesos de desarrollo de software en nuestro medio, no es un tema importante para muchas organizaciones. El resultado, pérdida de tiempo, dinero y esfuerzos en proyectos fracasados. La Cooperativa de Ahorro y Crédito Jardín Azuayo, es una institución financiera que por su crecimiento acelerado necesita ordenar y redefinir muchos de sus procesos y entre ellos está el de desarrollo de software. Por esta razón se consideró importante, dar a conocer una breve historia...

Fundamental properties of field emission-driven direct current microdischarges

International Nuclear Information System (INIS)

Rumbach, Paul; Go, David B.

2012-01-01

For half a century, it has been known that the onset of field emission in direct current microdischarges with gap sizes less than 10 μm can lead to breakdown at applied voltages far less than predicted by Paschen's law. It is still unclear how field emission affects other fundamental plasma properties at this scale. In this work, a one-dimensional fluid model is used to predict basic scaling laws for fundamental properties including ion density, electric field due to space charge, and current-voltage relations in the pre-breakdown regime. Computational results are compared with approximate analytic solutions. It is shown that field emission provides an abundance of cathode electrons, which in turn create large ion concentrations through ionizing collisions well before Paschen's criterion for breakdown is met. Breakdown due to ion-enhanced field emission occurs when the electric field due to space charge becomes comparable to the applied electric field. Simple scaling analysis of the 1D Poisson equation demonstrates that an ion density of n + ≈ 0.1V A ε 0 /qd 2 is necessary to significantly distort the electric field. Defining breakdown in terms of this critical ion density leads analytically to a simple, effective secondary emission coefficient γ ′ of the same mathematical form initially suggested by Boyle and Kisliuk [Phys. Rev. 97, 255 (1955)].

Trans-spinal direct current stimulation for the modulation of the lumbar spinal motor networks

NARCIS (Netherlands)

Kuck, Alexander

2018-01-01

Trans-spinal Direct Current Stimulation (tsDCS) is a noninvasive neuromodulatory tool for the modulation of the spinal neurocircuitry. Initial studies have shown that tsDCS is able to induce a significant and lasting change in spinal-reflex- and corticospinal information processing. It is therefore

Direct current hopping conductance in one-dimensional diagonal disordered systems

Institute of Scientific and Technical Information of China (English)

Ma Song-Shan; Xu Hui; Liu Xiao-Liang; Xiao Jian-Rong

2006-01-01

Based on a tight-binding disordered model describing a single electron band, we establish a direct current (dc) electronic hopping transport conductance model of one-dimensional diagonal disordered systems, and also derive a dc conductance formula. By calculating the dc conductivity, the relationships between electric field and conductivity and between temperature and conductivity are analysed, and the role played by the degree of disorder in electronic transport is studied. The results indicate the conductivity of systems decreasing with the increase of the degree of disorder, characteristics of negative differential dependence of resistance on temperature at low temperatures in diagonal disordered systems, and the conductivity of systems decreasing with the increase of electric field, featuring the non-Ohm's law conductivity.

Testing for causality between the foreign direct investment, current account deficit, GDP and total credit: Evidence from G7

Directory of Open Access Journals (Sweden)

Akbas Yusuf Ekrem

2013-01-01

Full Text Available In this study, countries were analyzed between 1990 and 2011 in order to determine whether a causal relationship exists among current account deficit, GDP, foreign direct investment, and total credits of G7. Analysis took into account the cross-sectional dependence and was applied to test the causality among the variables form the panel. Firstly, panel unit root tests were used for determining stationary of variables. As a result of the panel unit root tests, it was found that GDP and foreign direct investment have a stationary structure and that total credits and current account deficit contain unit root. In order to see whether there is a long-term relationship among the variables or not, the panel co-integration test was used. As a result of the test, it was concluded that there is a co-integration relationship among the series. The possibility of a causal relationship was analyzed among the variables using the causality test developed by Elena Ivona Dumitrescu and Christophe Hurlin (2012. Results of the analysis showed a unidirectional causal relationship from current account deficit and foreign direct investment to GDP. Bidirectional causality was found between current account deficit and total credits. Finally, a unidirectional relationship was found from foreign direct investment to current account deficit and total credits.

Energy saving in the sugar cane agroindustry; Ahorro de energia en la agroindustria azucarera canera

Energy Technology Data Exchange (ETDEWEB)

Zedillo Ponce de Leon, Luis [Grupo de paises Latinoamericanos y del Caribe exportadores de azucar (Mexico)

1996-07-01

The traditional sugar mill is inefficient from the energy point of view. Most of the sugar mills were designed to use all the available bagasse, due to the risk of spontaneous ignition and environmental pollution. Consequently, the steam generators, the turbines and other components were designed to work with low efficiencies. Each ton of sugar produced generates a power potential equivalent to four to six oil barrels (bagasse and residues). That is to say, a sugar mill is capable of producing 500 ton/day of sugar, equivalent to an oil well of 2000 to 3000 barrels/day and one thermoelectric power plant of 15,000 kW. Under this context an analysis is made of the sugar mills in Latin America and the Caribbean as one of the ways of increasing their efficiency and obtain great energy savings. As far as steam generation the appropriate use of energy is dictated by the boilers' efficiency. [Spanish] El ingenio azucarero tradicional es ineficiente desde el punto de vista energetico. La mayoria de los ingenios azucareros se disenaron para usar todo el bagazo disponible, debido al riesgo de ignicion espontanea y contaminacion. En consecuencia, los generadores de vapor, las turbinas y demas componentes fueron disenados para trabajar con bajas eficiencias. Cada tonelada de azucar producida genera una potencialidad energetica equivalente de cuatro a seis barriles de petroleo (bagazo y residuos). Es decir, un ingenio capaz de producir 500 ton/dia de azucar equivalente a un pozo de petroleo de 2000 a 3000 barriles/dia y una termoelectrica de 15000 kW. Bajo este contexto se hace un analisis del ingenio azucarero en Latinoamerica y el Caribe como una de las vias para incrementar su eficiencia y lograr grandes ahorros en la energia. En cuanto a generacion de vapor se refiere, el buen uso de la energia viene expresado por la eficiencia de las calderas.

Current direction and CTD data from moored current meter and CTD casts in the Delaware Bay from 1984-01-01 to 1984-12-01 (NODC Accession 8600001)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction and CTD data were collected using moored current meter and CTD casts in the Delaware Bay from January 1, 1984 to December 1, 1985. Data were...

Current direction and CTD data from moored current meter and CTD casts in the Atlantic Ocean from 1980-08-04 to 1981-08-14 (NODC Accession 8200240)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction and CTD data were collected using moored current meter and CTD casts in the Atlantic Ocean from August 4, 1980 to August 14, 1981. Data were...

Efficacy of transcranial direct-current stimulation (tDCS) in women with provoked vestibulodynia: study protocol for a randomized controlled trial.

Science.gov (United States)

Morin, Annie; Léonard, Guillaume; Gougeon, Véronique; Waddell, Guy; Bureau, Yves-André; Girard, Isabelle; Morin, Mélanie

2016-05-14

Provoked vestibulodynia is the most common form of vulvodynia. Despite its high prevalence and deleterious sexual, conjugal, and psychological repercussions, effective evidence-based interventions for provoked vestibulodynia remain limited. For a high proportion of women, significant pain persists despite the currently available treatments. Growing evidence suggests that the central nervous system (CNS) could play a key role in provoked vestibulodynia; thus, treatment targeting the CNS, rather than localized dysfunctions, may be beneficial for women suffering from provoked vestibulodynia. In this study, we aim to build on the promising results of a previous case report and evaluate whether transcranial direct-current stimulation, a non-invasive brain stimulation technique targeting the CNS, could be an effective treatment option for women with provoked vestibulodynia. This single-center, triple-blind, parallel group, randomized, controlled trial aims to compare the efficacy of transcranial direct-current stimulation with sham transcranial direct-current stimulation in women with provoked vestibulodynia. Forty women diagnosed with provoked vestibulodynia by a gynecologist, following a standardized treatment protocol, are randomized to either active transcranial direct-current stimulation treatment for ten sessions of 20 minutes at an intensity of 2 mA or sham transcranial direct-current stimulation over a 2-week period. Outcome measures are collected at baseline, 2 weeks after treatment and at 3-month follow-up. The primary outcome is pain during intercourse, assessed with a numerical rating scale. Secondary measurements focus on the sexual function, vestibular pain sensitivity, psychological distress, treatment satisfaction, and the patient's global impression of change. To our knowledge, this study is the first randomized controlled trial to examine the efficacy of transcranial direct-current stimulation in women with provoked vestibulodynia. Findings from this

Technical and economical assessment of the options for energy saving in the library of the Universidad Autonoma Metropolitana-Azcapotzalco; Evaluacion tecnico economica de opciones para el ahorro de energia en la biblioteca de la Universidad Autonoma Metropolitana-Azcapotzalco

Energy Technology Data Exchange (ETDEWEB)

Bratu, N; Campero, E; Dorantes, R; Fuentes, V; Figueroa, A; Garcia, R; Zekkour, A [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D. F. (Mexico)

1994-12-31

This paper presents a diagnosis of the electrical energy consumption in the library of the Azcapotzalco Unit of the Universidad Autonoma Metropolitana, to determine the actions that can be implemented for energy conservation. This without disturbing the lighting and thermal comfort. The analysis showed that, by changing the reflecting surfaces of the lighting lamps, the number of units can be reduced, without lowering the illumination level below the recommended values. The saving was estimated for replacement of the fluorescent lamps for others of metallic halogenides in the areas where the ceiling is high; for the installation of switches to improve the selectivity in turning on and turning off the lamps, achieving this way a better usage of the natural light; for the reduction of the electric load of the air conditioning units which will be obtained in incorporating induced draft shafts; and for an improvement in the electric and ballast installation. For the actions that turned out to be redeemable in three years the assistance of the Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE) of the Comision Federal de Electricidad (CFE) has been available. It is expected that the execution of the modifications will be carried out in the November and December months of 1993, and the results will be evaluated in 1994. [Espanol] En este trabajo se presenta un diagnostico del consumo de energia electrica en la biblioteca de la Unidad Azcapotzalco de la Universidad Autonoma Metropolitana para determinar las acciones que se pueden llevar a cabo para ahorrar energia electrica. Esto sin deteriorar el confort luminico y termico. El analisis mostro que, cambiando las superficies reflectoras de las luminarias, se puede reducir el numero de lamparas, sin que el nivel de iluminacion quede debajo de los valores recomendados. Se estimaron ahorros: por la sustitucion de las lamparas fluorescentes por otras de halogenuros metalicos en las partes donde el

Technical and economical assessment of the options for energy saving in the library of the Universidad Autonoma Metropolitana-Azcapotzalco; Evaluacion tecnico economica de opciones para el ahorro de energia en la biblioteca de la Universidad Autonoma Metropolitana-Azcapotzalco

Energy Technology Data Exchange (ETDEWEB)

Bratu, N.; Campero, E.; Dorantes, R.; Fuentes, V.; Figueroa, A.; Garcia, R.; Zekkour, A. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D. F. (Mexico)

1993-12-31

This paper presents a diagnosis of the electrical energy consumption in the library of the Azcapotzalco Unit of the Universidad Autonoma Metropolitana, to determine the actions that can be implemented for energy conservation. This without disturbing the lighting and thermal comfort. The analysis showed that, by changing the reflecting surfaces of the lighting lamps, the number of units can be reduced, without lowering the illumination level below the recommended values. The saving was estimated for replacement of the fluorescent lamps for others of metallic halogenides in the areas where the ceiling is high; for the installation of switches to improve the selectivity in turning on and turning off the lamps, achieving this way a better usage of the natural light; for the reduction of the electric load of the air conditioning units which will be obtained in incorporating induced draft shafts; and for an improvement in the electric and ballast installation. For the actions that turned out to be redeemable in three years the assistance of the Fideicomiso de Apoyo al Programa de Ahorro de Energia del Sector Electrico (FIDE) of the Comision Federal de Electricidad (CFE) has been available. It is expected that the execution of the modifications will be carried out in the November and December months of 1993, and the results will be evaluated in 1994. [Espanol] En este trabajo se presenta un diagnostico del consumo de energia electrica en la biblioteca de la Unidad Azcapotzalco de la Universidad Autonoma Metropolitana para determinar las acciones que se pueden llevar a cabo para ahorrar energia electrica. Esto sin deteriorar el confort luminico y termico. El analisis mostro que, cambiando las superficies reflectoras de las luminarias, se puede reducir el numero de lamparas, sin que el nivel de iluminacion quede debajo de los valores recomendados. Se estimaron ahorros: por la sustitucion de las lamparas fluorescentes por otras de halogenuros metalicos en las partes donde el

Composición quimicomineralógica de las materias primas y ahorro de energía en la industria del cemento

Directory of Open Access Journals (Sweden)

Soria Santamaría, Francisco

1982-06-01

Full Text Available In the field of energy saving, mainly thermic, in the cement industry, not only should we consider the possibilities in the technological process or the finished product, but also the influence of the chemical-mineral composition of the raw materials. The distinct parameters which fall into the reactivity of the crudes are analyzed, such as the size of the grain (fineness, chemical and mineral composition of the principal components. There follows an exposition of the importance of the minority components as smelting and mineralizers, finally emphasizing the interest and practical behaviour of some of them.

En el campo del ahorro de energía, principalmente térmica, en la industria cementera, no sólo deben contemplarse las posibilidades en cuanto al proceso tecnológico o el producto acabado, sino también la influencia de la composición quimicomineralógica de las materias primas. Se analizan los distintos parámetros que inciden en la reactividad de los crudos, tales como tamaño de grano (finura, composición química y mineralogía de los componentes principales. A continuación se hace una exposición de la importancia de los componentes minoritarios como fundentes y mineralizadores, destacando finalmente el interés y comportamiento práctico de alguno de ellos.

Energy saving in the auxiliaries consumption for circulation water pumps optimizing the thermal regime; Ahorro en el consumo de auxiliares por bombas de agua de circulacion optimando el regimen termico

Energy Technology Data Exchange (ETDEWEB)

Orozco Martinez, Roni [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1999-12-31

A methodology is proposed that should be followed in any thermal electric power plant to determine the load value at which a unit requires a second circulation water pump without affecting the thermal regime and avoiding an excessive auxiliaries consumption in partial loads. In applying this method the power plant would have an energy saving equivalent to the auxiliaries consumption during an hour, when the unit as operating at full load. [Espanol] Se propone una metodologia que debe seguirse en cualquier central termoelectrica para determinar el valor de la carga en la cual una unidad requiere de la segunda bomba de agua de circulacion sin afectar el regimen termico y evitadose un excesivo consumo de auxiliares en cargas parciales. Al aplicar este metodo la central tendria un ahorro de energia equivalente al consumo de auxiliares durante una hora cuando la unidad esta generando su maxima carga.

Energy saving in the auxiliaries consumption for circulation water pumps optimizing the thermal regime; Ahorro en el consumo de auxiliares por bombas de agua de circulacion optimando el regimen termico

Energy Technology Data Exchange (ETDEWEB)

Orozco Martinez, Roni [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

A methodology is proposed that should be followed in any thermal electric power plant to determine the load value at which a unit requires a second circulation water pump without affecting the thermal regime and avoiding an excessive auxiliaries consumption in partial loads. In applying this method the power plant would have an energy saving equivalent to the auxiliaries consumption during an hour, when the unit as operating at full load. [Espanol] Se propone una metodologia que debe seguirse en cualquier central termoelectrica para determinar el valor de la carga en la cual una unidad requiere de la segunda bomba de agua de circulacion sin afectar el regimen termico y evitadose un excesivo consumo de auxiliares en cargas parciales. Al aplicar este metodo la central tendria un ahorro de energia equivalente al consumo de auxiliares durante una hora cuando la unidad esta generando su maxima carga.

Direct current magnetron sputter-deposited ZnO thin films

International Nuclear Information System (INIS)

Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong; Knipp, Dietmar

2011-01-01

Zinc oxide (ZnO) is a very promising electronic material for emerging transparent large-area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 150 nm to 750 nm were deposited on glass substrates. The deposition pressure and the substrate temperature were varied from 12 mTorr to 25 mTorr, and from room temperature to 450 deg. C, respectively. The influence of the film thickness, deposition pressure and the substrate temperature on structural and optical properties of the ZnO films was investigated using atomic force microscopy (AFM) and ultraviolet-visible (UV-Vis) spectrometer. The experimental results reveal that the film thickness, deposition pressure and the substrate temperature play significant role in the structural formation and the optical properties of the deposited ZnO thin films.

Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion

DEFF Research Database (Denmark)

Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

2016-01-01

BACKGROUND: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atri...

GOBERNANZA MULTIFIDUCIARIA DE STAKEHOLDERS: ANÁLISIS COMPARADO DE LA EFICIENCIA DE BANCOS Y CAJAS DE AHORROS. / MULTIFIDUCIARY GOVERNANCE OF STAKEHOLDERS: A COMPARATIVE ANALYSIS OF THE EFFICIENCY OF BANKS AND SAVING BANKS.

Directory of Open Access Journals (Sweden)

Jose Luis RETOLAZA

2012-05-01

Full Text Available Las cajas de ahorros Españolas son posiblemente el caso más significativo a nivel mundial de entidades multistakeholders, no sólo por su misión, sino también en su gobernanza. La teoría multifiduciaria de los stakeholders plantea, al menos de forma teórica lo que en las cajas de ahorros ha sido una realidad por más de un siglo. Así, las cajas se convierten en un “caso de laboratorio” para analizar la viabilidad e idoneidad de una gobernanza participada por el conjunto de stakeholders de la organización. Nuestra hipótesis es que la gobernanza multistakeholder, así como la orientación hacia los stakeholders, generan un planteamiento estratégico diferente, no centrado en los beneficios. Por tanto, la gobernanza multifiduciaria puede perfectamente ser más ineficiente en relación con indicadores económico-financieros referidos a los shareholders de una entidad. Sin embargo, estas entidades deberían ser más eficientes si se tienen en cuenta indicadores relacionados con la generación de valor social. Con el fin de contrastar la eficiencia relativa hemos utilizando la población de bancos y cajas de España y los datos de 2009, utilizando la técnica de Análisis Envolvente de Datos con objeto de comparar la eficiencia económica, social y global de ambos tipos de entidades. Los resultados indican una diferenciación significativa entre estos dos grupos de entidades financieras en relación con la eficiencia social y económica, si bien no ocurre lo mismo cuando se utiliza la eficiencia global –económica más social-. Por lo que podemos concluir que la eficiencia en la gestión entre inputs y outputs en cajas de ahorros y bancos es similar. / Probably, Spanish savings banks are the most significant worldwide multistakeholders entities, not only because of their mission, but also in their governance. The stakeholder multifiduciary theory, establishes at least theoretically what the saving banks has been a reality for more than

Spreading depolarizations have prolonged direct current shifts and are associated with poor outcome in brain trauma

DEFF Research Database (Denmark)

Hartings, Jed A; Watanabe, Tomas; Bullock, M Ross

2011-01-01

, although prolonged events have not been observed in animal models. To determine whether detrimental penumbral-type depolarizations occur in human brain trauma, we analysed electrocorticographic recordings obtained by subdural electrode-strip monitoring during intensive care. Of 53 patients studied, 10......Cortical spreading depolarizations occur spontaneously after ischaemic, haemorrhagic and traumatic brain injury. Their effects vary spatially and temporally as graded phenomena, from infarction to complete recovery, and are reflected in the duration of depolarization measured by the negative direct...... current shift of electrocorticographic recordings. In the focal ischaemic penumbra, peri-infarct depolarizations have prolonged direct current shifts and cause progressive recruitment of the penumbra into the core infarct. In traumatic brain injury, the effects of spreading depolarizations are unknown...

Transcranial direct current stimulation transiently increases the blood-brain barrier solute permeability in vivo

Science.gov (United States)

Shin, Da Wi; Khadka, Niranjan; Fan, Jie; Bikson, Marom; Fu, Bingmei M.

2016-03-01

Transcranial Direct Current Stimulation (tDCS) is a non-invasive electrical stimulation technique investigated for a broad range of medical and performance indications. Whereas prior studies have focused exclusively on direct neuron polarization, our hypothesis is that tDCS directly modulates endothelial cells leading to transient changes in blood-brain-barrier (BBB) permeability (P) that are highly meaningful for neuronal activity. For this, we developed state-of-the-art imaging and animal models to quantify P to various sized solutes after tDCS treatment. tDCS was administered using a constant current stimulator to deliver a 1mA current to the right frontal cortex of rat (approximately 2 mm posterior to bregma and 2 mm right to sagittal suture) to obtain similar physiological outcome as that in the human tDCS application studies. Sodium fluorescein (MW=376), or FITC-dextrans (20K and 70K), in 1% BSA mammalian Ringer was injected into the rat (SD, 250-300g) cerebral circulation via the ipsilateral carotid artery by a syringe pump at a constant rate of ~3 ml/min. To determine P, multiphoton microscopy with 800-850 nm wavelength laser was applied to take the images from the region of interest (ROI) with proper microvessels, which are 100-200 micron below the pia mater. It shows that the relative increase in P is about 8-fold for small solute, sodium fluorescein, ~35-fold for both intermediate sized (Dex-20k) and large (Dex-70k) solutes, 10 min after 20 min tDCS pretreatment. All of the increased permeability returns to the control after 20 min post treatment. The results confirmed our hypothesis.

Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

Energy Technology Data Exchange (ETDEWEB)

Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu, E-mail: sde@che.iitkgp.ernet.in

2015-12-31

Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

International Nuclear Information System (INIS)

Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu

2015-01-01

Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

DEFF Research Database (Denmark)

Preindl, Matthias; Schaltz, Erik

2010-01-01

In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring...... the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress...

Methods for Specific Electrode Resistance Measurement during Transcranial Direct Current Stimulation

Science.gov (United States)

Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q.; Bikson, Marom

2014-01-01

Background Transcranial Direct Current Stimulation (tDCS) is investigated to treat a wide range of neuropsychiatric disorders, for rehabilitation, and for enhancing cognitive performance. The monitoring of electrode resistance before and during tDCS is considered important for tolerability and safety, where an unusually high resistance is indicative of undesired electrode or poor skin contact conditions. Conventional resistance measurement methods do not isolate individual electrode resistance but rather measures overall voltage. Moreover, for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. Objective We propose a novel method for monitoring of the individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low-intensity and low-frequency sinusoids with electrode– specific frequencies) and a single sentinel electrode (not used for DC). Methods To validate this methodology, we developed lumped-parameter models of two and multi-electrode tDCS. Approaches with and without a sentinel electrode were solved and underlying assumptions identified. Assumptions were tested and parameterized in healthy participants using forearm stimulation combining tDCS (2 mA) and sinusoidal test-signals (38 μA and 76 μA peak to peak at 1 Hz, 10 Hz, and 100 Hz) and an in vitro test (where varied electrode failure modes were created). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. Results A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. For multi-electrode resistance tracking, cross talk was aggravated with electrode proximity and current/resistance mismatches, but could be corrected using proposed approaches. Average voltage and average pain scores were not significantly different across test current intensities and frequencies (two-way repeated measures ANOVA) indicating the

Inter- and Intra-individual Variability in Response to Transcranial Direct Current Stimulation (tDCS) at Varying Current Intensities.

Science.gov (United States)

Chew, Taariq; Ho, Kerrie-Anne; Loo, Colleen K

2015-01-01

Translation of transcranial direct current stimulation (tDCS) from research to clinical practice is hindered by a lack of consensus on optimal stimulation parameters, significant inter-individual variability in response, and in sufficient intra-individual reliability data. Inter-individual differences in response to anodal tDCS at a range of current intensities were explored. Intra-individual reliability in response to anodal tDCS across two identical sessions was also investigated. Twenty-nine subjects participated in a crossover study. Anodal-tDCS using four different current intensities (0.2, 0.5, 1 and 2 mA), with an anode size of 16 cm2, was tested. The 0.5 mA condition was repeated to assess intra-individual variability. TMS was used to elicit 40 motor-evoked potentials (MEPs) before 10 min of tDCS, and 20 MEPs at four time-points over 30 min following tDCS. ANOVA revealed no main effect of TIME for all conditions except the first 0.5 mA condition, and no differences in response between the four current intensities. Cluster analysis identified two clusters for the 0.2 and 2 mA conditions only. Frequency distributions based on individual subject responses (excitatory, inhibitory or no response) to each condition indicate possible differential responses between individuals to different current intensities. Test-retest reliability was negligible (ICC(2,1) = -0.50). Significant inter-individual variability in response to tDCS across a range of current intensities was found. 2 mA and 0.2 mA tDCS were most effective at inducing a distinct response. Significant intra-individual variability in response to tDCS was also found. This has implications for interpreting results of single-session tDCS experiments. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Can the use of pulsed direct current induce oscillation in the applied pressure during spark plasma sintering?

International Nuclear Information System (INIS)

Salamon, David; Eriksson, Mirva; Nygren, Mats; Shen Zhijian

2012-01-01

The spark plasma sintering (SPS) process is known for its rapid densification of metals and ceramics. The mechanism behind this rapid densification has been discussed during the last few decades and is yet uncertain. During our SPS experiments we noticed oscillations in the applied pressure, related to a change in electric current. In this study, we investigated the effect of pulsed electrical current on the applied mechanical pressure and related changes in temperature. We eliminated the effect of sample shrinkage in the SPS setup and used a transparent quartz die allowing direct observation of the sample. We found that the use of pulsed direct electric current in our apparatus induces pressure oscillations with the amplitude depending on the current density. While sintering Ti samples we observed temperature oscillations resulting from pressure oscillations, which we attribute to magnetic forces generated within the SPS apparatus. The described current–pressure–temperature relations might increase understanding of the SPS process.

Alternatives for blocking direct current in AC system neutrals at the Radisson/LG2 complex

International Nuclear Information System (INIS)

Eitzmann, M.A.; Walling, R.A.; Sublich, M.; Kah, A.; Huynh, H.; Granger, M.; Dutil, A.

1992-01-01

Severe offset saturation results from the passage of direct current through power transformers. Such direct current can arise from geomagnetic disturbances, or resistive coupling of the substation ground to HVDC earth electrodes. This paper documents the development of alternative approaches for the design and application of blocking devices placed between transformer neutrals and the substation ground. System constraints on the impedance and overvoltage limitation of the neutral blocking device (NBD) are covered. Three alternative NBD schemes are developed and optimized. System performance of the NBD is discussed, as are the practical implementation considerations for this unconventional equipment application. Although the paper focuses on the NBD requirements of Hydro-Quebec's Radisson/LG2 complex, the fundamental information is applicable to any situation where dc must be clocked from a power transformer neutral in a system designed for effectively-grounded operation

Pediatric neurology training in Canada: current status and future directions.

Science.gov (United States)

Doja, Asif

2012-05-01

Child neurology training in Canada has changed considerably over time, with increasing requirements for standardized teaching of the fundamentals of child neurology and the CanMEDS competencies. We sought to determine the current status of child neurology training in Canada as well future directions for training. A web-based survey was sent to program directors (PD's) of active pediatric neurology training programs. General questions about the programs were asked, as well as about success at the Royal College of Physicians and Surgeons of Canada (RCPSC) exam, breakdown of rotations, views on CanMEDS roles and questions on the future of pediatric neurology. 9/9 PD's completed the survey. 96.5% of all trainees successfully passed their RCPSC exam from 2001-2006. Breakdowns of the number and type of rotations for each year of training were provided. All CanMEDS roles were deemed to be important by PD's and programs have developed unique strategies to teach and assess these roles.92.6% of trainees chose to go into academic practice, with the most popular subspecialty being epilepsy. All PD's favour joint training sessions particularly for neurogenetics and neuromuscular disease. Overall, PD's suggest recruitment for future child neurologists at the medical student level but are divided as to whether we are currently training too few or too many child neurologists. This survey provides a view of the current state of pediatric neurology training in Canada and suggestions for further development of post-graduate training. In particular, attention should be given to joint educational programs as well as urgently assessing the manpower needs of child neurologists.

Grading of direct laryngoscopy. A survey of current practice.

Science.gov (United States)

Cohen, A M; Fleming, B G; Wace, J R

1994-06-01

One hundred and twenty anaesthetists (30 of each grade), from three separate regions, were interviewed as to how they recorded the appearance of laryngeal structures at direct laryngoscopy and about their knowledge of the commonly used numerical grading system. About two-thirds of anaesthetists surveyed (69.2%) used the numerical grading system, but of these, over half could not identify a 'grade 2' laryngoscopic appearance correctly. Of anaesthetists who did not use the numerical method, over half could not correctly state the difference between a 'grade 2' and a 'grade 3' laryngoscopic appearance. Over 40% of anaesthetists stated incorrectly that the grading should be made on the initial view, even when laryngeal pressure had been needed. Junior anaesthetists were more likely to use the numerical method of recording. The results show that there is unacceptable uncertainty and inaccuracy in the use of the numerical grading system by users as well as non-users, which makes the current routine clinical use of the numerical grading system unsatisfactory.

Current direction and CTD data from moored current meter and CTD casts in the North Pacific Ocean from 1979-02-05 to 1980-12-01 (NODC Accession 8300042)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction and CTD data were collected using moored current meter and CTD casts in the North Pacific Ocean from February 5, 1979 to December 1, 1980. Data...

Direct current induced short-term modulation of the left dorsolateral prefrontal cortex while learning auditory presented nouns

Directory of Open Access Journals (Sweden)

Meyer Martin

2009-07-01

Full Text Available Abstract Background Little is known about the contribution of transcranial direct current stimulation (tDCS to the exploration of memory functions. The aim of the present study was to examine the behavioural effects of right or left-hemisphere frontal direct current delivery while committing to memory auditory presented nouns on short-term learning and subsequent long-term retrieval. Methods Twenty subjects, divided into two groups, performed an episodic verbal memory task during anodal, cathodal and sham current application on the right or left dorsolateral prefrontal cortex (DLPFC. Results Our results imply that only cathodal tDCS elicits behavioural effects on verbal memory performance. In particular, left-sided application of cathodal tDCS impaired short-term verbal learning when compared to the baseline. We did not observe tDCS effects on long-term retrieval. Conclusion Our results imply that the left DLPFC is a crucial area involved in short-term verbal learning mechanisms. However, we found further support that direct current delivery with an intensity of 1.5 mA to the DLPFC during short-term learning does not disrupt longer lasting consolidation processes that are mainly known to be related to mesial temporal lobe areas. In the present study, we have shown that the tDCS technique has the potential to modulate short-term verbal learning mechanism.

Counteracting Fatigue in Multiple Sclerosis with Right Parietal Anodal Transcranial Direct Current Stimulation

OpenAIRE

Hanken, Katrin; Bosse, Mona; M?hrke, Kim; Eling, Paul; Kastrup, Andreas; Antal, Andrea; Hildebrandt, Helmut

2016-01-01

BACKGROUND: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time (RT) and errors with prolonged time-on-task. OBJECTIVES: The aim of this study was to investigate whether anodal transcranial direct current stimulation (tDCS) over the right parietal or frontal cortex counteracts fatigue-associated vigilance decrement and subjective fatigue. METHODS: In study I, a randomized double-blind placebo-controll...

Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

Energy Technology Data Exchange (ETDEWEB)

Couëdel, L., E-mail: lenaic.couedel@univ-amu.fr; Kumar, K. Kishor; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS, Aix-Marseille Université, 13397 Marseille (France)

2014-12-15

Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

Modulation of Brain Activity with Noninvasive Transcranial Direct Current Stimulation (tDCS): Clinical Applications and Safety Concerns

Science.gov (United States)

Zhao, Haichao; Qiao, Lei; Fan, Dongqiong; Zhang, Shuyue; Turel, Ofir; Li, Yonghui; Li, Jun; Xue, Gui; Chen, Antao; He, Qinghua

2017-01-01

Transcranial direct current stimulation (tDCS) is a widely-used tool to induce neuroplasticity and modulate cortical function by applying weak direct current over the scalp. In this review, we first introduce the underlying mechanism of action, the brief history from discovery to clinical scientific research, electrode positioning and montages, and parameter setup of tDCS. Then, we review tDCS application in clinical samples including people with drug addiction, major depression disorder, Alzheimer's disease, as well as in children. This review covers the typical characteristics and the underlying neural mechanisms of tDCS treatment in such studies. This is followed by a discussion of safety, especially when the current intensity is increased or the stimulation duration is prolonged. Given such concerns, we provide detailed suggestions regarding safety procedures for tDCS operation. Lastly, future research directions are discussed. They include foci on the development of multi-tech combination with tDCS such as with TMS and fMRI; long-term behavioral and morphological changes; possible applications in other research domains, and more animal research to deepen the understanding of the biological and physiological mechanisms of tDCS stimulation. PMID:28539894

Investigation of students’ intermediate conceptual understanding levels: the case of direct current electricity concepts

International Nuclear Information System (INIS)

Aktan, D Cobanoglu

2013-01-01

Conceptual understanding is one of the main topics in science and physics education research. In the majority of conceptual understanding studies, students’ understanding levels were categorized dichotomously, either as alternative or scientific understanding. Although they are invaluable in many ways, namely developing new instructional materials and assessment instruments, students’ alternative understandings alone are not sufficient to describe students’ conceptual understanding in detail. This paper introduces an example of a study in which a method was developed to assess and describe students’ conceptual understanding beyond alternative and scientific understanding levels. In this study, six undergraduate students’ conceptual understanding levels of direct current electricity concepts were assessed and described in detail by using their answers to qualitative problems. In order to do this, conceptual understanding indicators are described based on science and mathematics education literature. The students’ understanding levels were analysed by assertion analysis based on the conceptual understanding indicators. The results indicated that the participants demonstrated three intermediate understanding levels in addition to alternative and scientific understanding. This paper presents the method and its application to direct current electricity concepts. (paper)

Direct current electrotherapy for internal haemorrhoids: experience in a tertiary health institution

Science.gov (United States)

Olatoke, Samuel; Adeoti, Moses; Agodirin, Olayide; Ajape, Abdulwahab; Agbola, John

2014-01-01

Introduction Haemorrhoids disease is one of the most frequently occurring disabling conditions of the anorectum. We re-present the method, advantages and results of using direct current electrotherapy in the treatment of haemorrhoids. Methods Symptomatic grades 1, 2 or 3 internal and mixed haemorroids were treated. Exposure and evaluation was with an operative proctoscope which visualized one-eighth of the anal canal at a time. All diseased segments were treated per visit, indicators of successful treatment were, darkening of the treated segment, immediate shrinking of the haemorrhoid and ceasation of popping sound of gas release at the probe tip. Patients were followed up for two weeks. No bowel preparations, medications, anesthesia nor admission was required. Results Four hundred and fifty six segments were exposed, 252(55.3%) were diseased. eight patients with either grades 2 or 3 diseases required two treatment visits. The most common symptom was rectal bleeding (94.7%), followed by prolapsed but manually reduced hemorrhoids (68%). Prolapse of tuft of haemorrhoidal tissue with spontaneous return was seen in 59.6%, anal pain in 29.8%, and itching in 3.5%. the median number treated segments per patient was 4. No complication was encountered. All patients treated remained symptom free at a mean duration of follow up of 16 months. Conclusion Direct current electrotherapy is an effective, painless and safe out-patient treatment method for grades 1 to 3 internal and mixed hemorrhoid disease. PMID:25419283

Characterization of manganese dioxide electrodeposited by pulse and direct current for electrochemical capacitor

International Nuclear Information System (INIS)

Adelkhani, H.; Ghaemi, M.

2010-01-01

This paper describes the electrochemical capacitor behavior of manganese dioxide (MD, MnO 2 ) samples that were prepared by direct current (DCMD) and pulse current (PCMD) electrodeposition. The capacitive characteristics of the samples were studied in 0.5 M aqueous Na 2 SO 4 solution using the cyclic voltammetry (CV) method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), chemical composition analyses and the Barrett-Joyner-Halenda (BJH) method were employed to characterize the samples. In the study of the effect of scan rate on capacitance, it was revealed that PCMD displayed higher capacities than DCMD for all scan rates. The higher capacitive performance of PCMD was attributed to its porosity (specific surface area, pore volume, and pore-size distribution), chemical composition and structural properties.

Direct current linear measurement sub-assembly data and test methods. Nuclear electronic equipment for control and monitoring panel

International Nuclear Information System (INIS)

1977-12-01

The M.C.H./M.E.N.T.3 document is concerned with sub-assemblies intended for measuring on a linear scale the neutron fluence rate or radiation dose rate when connected with nuclear detectors working in current. The symbols used are described. Some definitions and a bibliography are given. The main characteristics of direct current linear measurement sub-assemblies are then described together with corresponding test methods. This type of instrument indicates on a linear scale the level of a direct current applied to its input. The document reviews linear sub-assemblies for general purpose applications, difference amplifiers for monitoring, and averaging amplifiers. The document is intended for electronics manufacturers, designers, persons participating in acceptance trials and plant operators [fr

Counteracting fatigue in multiple sclerosis with right parietal anodal transcranial direct current stimulation

OpenAIRE

Katrin Hanken; Katrin Hanken; Mona Bosse; Kim Möhrke; Paul Eling; Andreas Kastrup; Andrea Antal; Helmut Hildebrandt; Helmut Hildebrandt

2016-01-01

Background: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time and errors with prolonged time-on-task. Objectives: The aim of this study was to investigate whether anodal transcranial direct current stimulation (tDCS) over the right parietal or frontal cortex counteracts fatigue-associated vigilance decrement and subjective fatigue. Methods: In study I, a randomized double-blind placebo-controlled study, anoda...

First direct observations linking confined supercritical turbidity currents to their depositional architecture and facies characteristics

Science.gov (United States)

Hage, S.; Cartigny, M.; Hughes Clarke, J. E.; Clare, M. A.; Sumner, E.; Hubbard, S. M.; Talling, P.; Lintern, G.; Stacey, C.; Vardy, M. E.; Hunt, J.; Vendettuoli, D.; Yokokawa, M.; Hizzett, J. L.; Vellinga, A. J.; Azpiroz, M.

2017-12-01

Turbidity currents transfer globally significant amounts of sediment via submarine channels from the continental margin to deep submarine fans. Submarine channel inception is thought to result from erosive, supercritical turbidity currents that are common in proximal settings of the marine realm. Recent monitoring of submarine processes have provided the first measurements of supercritical turbidity currents (Hughes Clarke, 2016), demonstrating that they drive the upstream migration of crescentic bedforms in confined submarine channels. Although upstream-migrating bedforms are common in confined channels across the world's oceans, there is considerable debate over the type of deposits that they produce. It is important to understand what types of deposit record these supercritical bedforms to potentially identify them from geological archives. For the first time, we combine direct measurements from supercritical field-scale turbidity currents with the facies and depositional architecture resulting from such flows. We show how the subsurface architecture evolves in a highly active channel at Squamish submarine delta, British Columbia, Canada. Repeated upstream migration of bedforms is found to create two main deposit geometries. First, regular back-stepping beds result from flow deceleration on the slightly-inclined sides of the bedforms. Second, lens-shaped scour fills composed of massive deposits result from erosion of the back-stepping beds by subsequent turbidity currents. We relate our findings to a range of ancient outcrop studies to demonstrate that supercritical flows are common in proximal settings through the geological record. This study provides the first direct observation-based model to identify confined supercritical turbidity currents and their associated upslope-migrating bedforms in the sedimentary record. This is important for correctly identifying the proximal sites of ancient submarine channels that served as past conduits for globally

On the structure of intermediate state created by the direct current

International Nuclear Information System (INIS)

Kan, Ya.S.; Frolov, V.A.

1974-01-01

Observations were made of the structure of an intermediate state formed at the destruction of superconductivity of a cylindrical tin sample by an electric current through it. For this purpose, there was determined the nature of the dependence of the magnetic permeability averaged over a section normal with the sample axis on the position of this section relative to the axis. the quantity actually measured was the inductance of a short (0.5 mm) superconductive probe coil embracing the sample and moving along the axis of the latter. In order the inductance were representatative of the magnetic permeability in the depth of a thick (5 mm in diameter) sample, measurements were made with a direct current by means of the device specially designed for this purpose; the operating principle and method for checking of this device being briefly described in the paper. The curves of oscillations of the inductance of the probe with the latter being moved along the sample suggested a conclusion that the structure of the intermediate state had a periodic nature (of the London type) with a period of 1.3 mm. The reduction of the oscillation amplitude and the increase of their average level while an increase of the current passing through the sample above the critical value (at constant temperature) indicated the reduction of the diameter of the core, being in the intermediate state, and an increase of the thickness of a normal layer. Measurements were made at temperatures (13-17)x10 -3 deg K below Tsub(k) with a current of 2-3 A in the sample

Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

Directory of Open Access Journals (Sweden)

Sophia Karok

Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

LAS CAJAS DE AHORRO Y LAS COOPERATIVAS DE CRÉDITO ANTE LA CRISIS: EVOLUCIÓN EN SU PRESENCIA TERRITORIAL Y EN SU OPERATIVA / SAVING BANKS AND CREDIT CO-OPERATIVES FACED WITH THE CRISIS: THE CHANGES IN THEIR LOCALIZATION AND PERFORMANCE

Directory of Open Access Journals (Sweden)

Jesús PAÚL GUTIÉRREZ

2010-01-01

Full Text Available El artículo estudia el impacto que la crisis económica y financiera está teniendo en las entidades bancarias de carácter social, en especial en sus estrategias de financiación y de localización territorial. En primer lugar, se analizan las crecientes necesidades de financiación de la economía española durante el pasado ciclo expansivo y el decisivo papel de las instituciones financieras en la canalización del ahorro externo. Posteriormente, se analiza la evolución de la presencia territorial de las cajas de ahorro y de las cooperativas de crédito, así como la distribución de sus operaciones activas y pasivas. El análisis se realiza diferenciando dos períodos, uno desde el inicio de los noventa hasta el verano de 2007, momento en el que se inicia la crisis, y un segundo período, desde el cuarto trimestre de 2007 hasta la actualidad. / This paper examines the impact that the international economic and financial crisis is having on the behaviour of Spanish social banking institutions, particularly in their funding and localization strategies. First of all, we analyse the growing net borrowing of the Spanish economy in the former economic expansion cycle and how the national financial institutions were the primary source of foreign financing. Secondly, we analyse the evolution of territorial localization of saving banks and credit co-operatives, and of their lending and borrowing transactions. In this analysis we are going to difference two periods: since the beginning of nineties until August 2007, the start of the international financial, and a second period since the fourth quarter 2007 until now.

Influence of Concurrent Finger Movements on Transcranial Direct Current Stimulation (tDCS)-Induced Aftereffects.

Science.gov (United States)

Shirota, Yuichiro; Terney, Daniella; Antal, Andrea; Paulus, Walter

2017-01-01

Transcranial direct current stimulation (tDCS) has been reported to have bidirectional influence on the amplitude of motor-evoked potentials (MEPs) in resting participants in a polarity-specific manner: anodal tDCS increased and cathodal tDCS decreased them. More recently, the effects of tDCS have been shown to depend on a number of additional factors. We investigated whether a small variety of movements involving target and non-target muscles could differentially modify the efficacy of tDCS. MEPs were elicited from the right first dorsal interosseous muscle, defined as the target muscle, by single pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). During M1 tDCS, which lasted for 10 min applying anodal, cathodal, or sham condition, the participants were instructed to squeeze a ball with their right hand (Task 1), to move their right index finger only in the medial (Task 2), in the lateral direction (Task 3), or in medial and lateral direction alternatively (Task 4). Anodal tDCS reduced MEP amplitudes measured in Task 1 and Task 2, but to a lesser extent in the latter. In Task 3, anodal tDCS led to greater MEP amplitudes than cathodal stimulation. Alternating movements resulted in no effect of tDCS on MEP amplitude (Task 4). The results are congruent with the current notion that the aftereffects of tDCS are highly variable relying on a number of factors including the type of movements executed during stimulation.

Current approaches and future directions in the treatment of leprosy

Directory of Open Access Journals (Sweden)

Worobec SM

2012-08-01

Full Text Available Sophie M WorobecDepartment of Dermatology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USAAbstract: This review surveys current treatments and future treatment trends in leprosy from a clinical perspective. The World Health Organization provides a multidrug treatment regimen that targets the Mycobacterium leprae bacillus which causes leprosy. Several investigational drugs are available for the treatment of drug-resistant M. leprae. Future directions in leprosy treatment will focus on: the molecular signaling mechanism M. leprae uses to avoid triggering an immune response; prospective studies of the side effects experienced during multiple-drug therapy; recognition of relapse rates post-completion of designated treatments; combating multidrug resistance; vaccine development; development of new diagnostic tests; and the implications of the recent discovery of a genetically distinct leprosy-causing bacillus, Mycobacterium lepromatosis.Keywords: epidemiology, leprosy, Hansen’s disease, multidrug resistance, multidrug therapy

Direct current magnetron sputtering deposition of InN thin films

International Nuclear Information System (INIS)

Cai Xingmin; Hao Yanqing; Zhang Dongping; Fan Ping

2009-01-01

In this paper, InN thin films were deposited on Si (1 0 0) and K9 glass by reactive direct current magnetron sputtering. The target was In metal with the purity of 99.999% and the gases were Ar (99.999%) and N 2 (99.999%). The properties of InN thin films were studied. Scanning electron microscopy (SEM) shows that the film surface is very rough and energy dispersive X-ray spectroscopy (EDX) shows that the film contains In, N and very little O. X-ray diffraction (XRD) and Raman scattering reveal that the film mainly contains hexagonal InN. The four-probe measurement shows that InN film is conductive. The transmission measurement demonstrates that the transmission of InN deposited on K9 glass is as low as 0.5% from 400 nm to 800 nm.

Automatic adjustment of bias current for direct current superconducting quantum interference device

International Nuclear Information System (INIS)

Makie-Fukuda, K.; Hotta, M.; Okajima, K.; Kado, H.

1993-01-01

A new method of adjusting the bias current of dc superconducting quantum interference device (SQUID) is described. It is shown that the signal-to-noise ratio of a SQUID magnetometer connected in a flux-locked loop configuration is proportional to the second harmonic of the output signal from the SQUID. A circuit configuration that can automatically optimize a SQUID's bias current by measuring this second harmonic and adjusting the bias current accordingly is proposed

Current Directions in Mediation Analysis

Science.gov (United States)

MacKinnon, David P.; Fairchild, Amanda J.

2010-01-01

Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables. PMID:20157637

Current Directions in Mediation Analysis

OpenAIRE

MacKinnon, David P.; Fairchild, Amanda J.

2009-01-01

Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables.

Actions and results of the management of energy saving of the CONDUMEX group; Acciones y resultados de la gerencia de ahorro de energia de grupo CONDUMEX

Energy Technology Data Exchange (ETDEWEB)

Sashida Key, Carlos; Jimenez Huerta, Arturo; Alavez Alcazar, Moises [Grupo Condumex, Industrias IEM, S.A. de C.V., Mexico, D.F. (Mexico)

1999-07-01

The purpose of this paper is to expose some practical cases that have been developed through the Energy Saving Management of GRUPO CONDUMEX, in different areas such as systems related to water, steam, electricity and compressed air. This experience has been compiled of diagnoses and actions that have been carried out in the companies inside and outside GRUPO CONDUMEX, and of systems with the purpose of making efficient the use of fuels and getting close to the energy indexes that are handled in other International companies of the same manufacture branch. [Spanish] Este trabajo tiene por objeto exponer algunos casos practicos que se han desarrollado a traves de la Gerencia de Ahorro de Energia de GRUPO CONDUMEX, en distintas areas tales como sistemas relacionados con agua, vapor, electricidad y aire comprimido. Esta experiencia ha sido recopilada de diagnosticos y acciones que se han llevado a cabo en las empresas dentro y fuera de GRUPO CONDUMEX, y de sistemas con la finalidad de eficientar el uso de los energeticos y acercarnos a los indices energeticos que se manejan en otras empresas internacionales del mismo ramo de fabricacion.

Effectiveness of anodal transcranial direct current stimulation in patients with chronic low back pain: Design, method and protocol for a randomised controlled trial

Directory of Open Access Journals (Sweden)

Luedtke Kerstin

2011-12-01

Full Text Available Abstract Background Electrical stimulation of central nervous system areas with surgically implanted stimulators has been shown to result in pain relief. To avoid the risks and side effects of surgery, transcranial direct current stimulation is an option to electrically stimulate the motor cortex through the skull. Previous research has shown that transcranial direct current stimulation relieves pain in patients with fibromyalgia, chronic neuropathic pain and chronic pelvic pain. Evidence indicates that the method is pain free, safe and inexpensive. Methods/Design A randomised controlled trial has been designed to evaluate the effect of transcranial direct current stimulation over the motor cortex for pain reduction in patients with chronic low back pain. It will also investigate whether transcranial direct current stimulation as a prior treatment enhances the symptom reduction achieved by a cognitive-behavioural group intervention. Participants will be randomised to receive a series of 5 days of transcranial direct current stimulation (2 mA, 20 mins or 20 mins of sham stimulation; followed by a cognitive-behavioural group programme. The primary outcome parameters will measure pain (Visual Analog Scale and disability (Oswestry Disability Index. Secondary outcome parameters will include the Fear Avoidance Beliefs Questionnaire, the Funktionsfragebogen Hannover (perceived function, Hospital Anxiety Depression Scale, bothersomeness and Health Related Quality of Life (SF 36, as well as Patient-Perceived Satisfactory Improvement. Assessments will take place immediately prior to the first application of transcranial direct current stimulation or sham, after 5 consecutive days of stimulation, immediately after the cognitive-behavioural group programme and at 4 weeks, 12 weeks and 24 weeks follow-up. Discussion This trial will help to determine, whether transcranial direct current stimulation is an effective treatment for patients with chronic low back

The Effectiveness of Transcranial Direct Current Stimulation (tDCS on Working Memory in Patients with Major Depression

Directory of Open Access Journals (Sweden)

Mahboube Ebadi

2017-08-01

Full Text Available Abstract Background: The aim of this study was to evaluate the effectiveness of of transcranial direct current stimulation (tDCS on working memory in patients with major depression. Materials and Methods: The research method was quasi-experimental with pretest and post-test and follow-up with control group. The research population comprised female outpatient referrals to private psychiatric centers and psychological counseling centers in Tehran in the first half of 2016, They had received a diagnosis of depression by a psychiatrist at least once. Of these, 30 females were selected as a sample group with convenience sampling method and based on the criteria of inclusion and exclusion and were divided randomly into two groups , experimental (n = 15 and control (n = 15 group. The experimental group received transcranial direct current stimulation (tDCS in 10 sessions, While this intervention was not provided to the control group. The data were collected by N-BACK. Analysis of variance with repeated measurments was used to test the research hypothesis. Results: The results showed that transcranial direct current stimulation (tDCS had a significant effect on increasing working memory and the impact will continue to follow up. Conclusion: Therefore, this approach can be used to improve working memory in people with major depression.

Direct-current substrate bias effects on amorphous silicon sputter-deposited films for thin film transistor fabrication

International Nuclear Information System (INIS)

Jun, Seung-Ik; Rack, Philip D.; McKnight, Timothy E.; Melechko, Anatoli V.; Simpson, Michael L.

2005-01-01

The effect that direct current (dc) substrate bias has on radio frequency-sputter-deposited amorphous silicon (a-Si) films has been investigated. The substrate bias produces a denser a-Si film with fewer defects compared to unbiased films. The reduced number of defects results in a higher resistivity because defect-mediated conduction paths are reduced. Thin film transistors (TFTs) that were completely sputter deposited were fabricated and characterized. The TFT with the biased a-Si film showed lower leakage (off-state) current, higher on/off current ratio, and higher transconductance (field effect mobility) than the TFT with the unbiased a-Si film

Development of an air-breathing direct methanol fuel cell with the cathode shutter current collectors

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yufeng; Liu, Xiaowei [Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education, Harbin 150001 (China); MEMS Center, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Peng; Zhang, Bo; Li, Jianmin; Deng, Huichao [MEMS Center, Harbin Institute of Technology, Harbin 150001 (China)

2010-06-15

An air-breathing direct methanol fuel cell with a novel cathode shutter current collector is fabricated to develop the power sources for consumer electronic devices. Compared with the conventional circular cathode current collector, the shutter one improves the oxygen consumption and mass transport. The anode and cathode current collectors are made of stainless steel using thermal stamping die process. Moreover, an encapsulation method using the tailor-made clamps is designed to assemble the current collectors and MEA for distributing the stress of the edges and inside uniformly. It is observed that the maximum power density of the air-breathing DMFC operating with 1 M methanol solution achieves 19.7 mW/cm{sup 2} at room temperature. Based on the individual DMFCs, the air-breathing stack consisting of 36 DMFC units is achieved and applied to power a notebook computer. (author)

Is transcranial direct current stimulation a potential method for improving response inhibition?☆

OpenAIRE

Kwon, Yong Hyun; Kwon, Jung Won

2013-01-01

Inhibitory control of movement in motor learning requires the ability to suppress an inappropriate action, a skill needed to stop a planned or ongoing motor response in response to changes in a variety of environments. This study used a stop-signal task to determine whether transcranial direct-current stimulation over the pre-supplementary motor area alters the reaction time in motor inhibition. Forty healthy subjects were recruited for this study and were randomly assigned to either the tran...

Current status of direct dark matter detection experiments

Science.gov (United States)

Liu, Jianglai; Chen, Xun; Ji, Xiangdong

2017-03-01

Much like ordinary matter, dark matter might consist of elementary particles, and weakly interacting massive particles are one of the prime suspects. During the past decade, the sensitivity of experiments trying to directly detect them has improved by three to four orders of magnitude, but solid evidence for their existence is yet to come. We overview the recent progress in direct dark matter detection experiments and discuss future directions.

FMIT direct-current beam monitor

International Nuclear Information System (INIS)

Brousseau, A.T.; Chamberlin, D.D.

1981-01-01

The prototype injector section for the Fusion Materials Irradiation Test (FMIT) Facility being developed at the Los Alamos National Laboratory requires that beam parameters be noninterceptively monitored. This report describes the application of a single toroidal core, coupled with very simple circuitry, that results in the production of a simple instrument, and eliminates the problems inherent in the Faraday cup technique for the current measurements of the FMIT injector beam

A study of direct- and pulse-current chromium electroplating on rotating cylinder electrode (RCE)

International Nuclear Information System (INIS)

Chang, J.H.; Hsu, F.Y.; Liao, M.J.; Huang, C.A.

2007-01-01

Direct- and pulse-current (DC and PC) chromium electroplating on Cr-Mo steel were performed in a sulfate-catalyzed chromic acid solution at 50 deg. C using a rotating cylinder electrode (RCE). The electroplating cathodic current densities were at 30, 40, 50 and 60 A dm -2 , respectively. The relationship between electroplating current efficiency and the rotating speed of the RCE was studied. The cross-sectional microstructure of Cr-deposit was examined by transmission electron microscope (TEM). Results showed that DC-plating exhibited higher current efficiency than the PC-plating under the same conditions of electroplating current density and the rotating speed. We found the critical rotating speed of RCE used in the chromium electroplating, above this rotating speed the chromium deposition is prohibited. At the same plating current density, the critical rotating speed for DC-plating was higher than that for PC-plating. The higher plating current density is, the larger difference in critical rotating speeds appears between DC- and PC-electroplating. Equiaxed grains, in a nanoscale size with lower dislocation density, nucleate on the cathodic surface in both DC- and PC-electroplating. Adjacent to the equiaxed grains, textured grains were found in other portion of chromium deposit. Fine columnar grains were observed in the DC-electroplated deposit. On the other hand, very long slender grains with high degree of preferred orientation were detected in PC-electroplated deposit

Direct observations of the Antarctic Slope Current transport at 113°E

Science.gov (United States)

Peña-Molino, B.; McCartney, M. S.; Rintoul, S. R.

2016-10-01

The Antarctic Slope Current (ASC), defined here as the region of westward flow along the continental slope off Antarctica, forms the southern limb of the subpolar gyres. It regulates the exchange of water across the shelf break and provides a path for interbasin westward transport. Despite its significance, the ASC remains largely unobserved around most of the Antarctic continent. Here we present direct velocity observations from a 17 month current meter moored array deployed across the continental slope between the 1000 and the 4200 m isobaths, in the southeastern Indian Ocean near 113°E. The observed time-mean flow consists of a surface-intensified jet associated with the Antarctic Slope Front (ASF) and a broader bottom-intensified westward flow that extends out to approximately the 4000 m isobath and is strongest along the upper slope. The time-mean transport of the ASC is -29.2 Sv. Fluctuations in the transport are large, typically exceeding the mean by a factor of 2. They are mainly due to changes in the northward extent of the current over the lower slope. However, seasonal changes in the wind also drive variations in the transport of the ASF and the flow in the upper slope. Both mean and variability are largely barotropic, thus invisible to traditional geostrophic methods.

ANODAL TRANSCRANIAL DIRECT CURRENT STIMULATION (TDCS) INCREASES ISOMETRIC STRENGTH OF SHOULDER ROTATORS MUSCLES IN HANDBALL PLAYERS.

Science.gov (United States)

Hazime, Fuad Ahmad; da Cunha, Ronaldo Alves; Soliaman, Renato Rozenblit; Romancini, Ana Clara Bezerra; Pochini, Alberto de Castro; Ejnisman, Benno; Baptista, Abrahão Fontes

2017-06-01

Weakness of the rotator cuff muscles can lead to imbalances in the strength of shoulder external and internal rotators, change the biomechanics of the glenohumeral joint and predispose an athlete to injury. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has demonstrated promising results in a variety of health conditions. However few studies addressed its potential approach in the realm of athletics. The purpose of this study was to investigate if transcranial direct current stimulation (tDCS) technique increases the isometric muscle strength of shoulder external and internal rotators in handball athletes. Randomized, double-blind, placebo-controlled, crossover study. Eight female handball players aged between 17 and 21 years (Mean=19.65; SD=2.55) with 7.1 ± 4.8 years of experience in training, participating in regional and national competitions were recruited. Maximal voluntary isometric contraction (MVIC) of shoulder external and internal rotator muscles was evaluated during and after 30 and 60 minutes post one session of anodal and sham current (2mA; 0.057mA/cm 2 ) with a one-week interval between stimulations. Compared to baseline, MVIC of shoulder external and internal rotators significantly increased after real but not sham tDCS. Between-group differences were observed for external and internal rotator muscles. Maximal voluntary isometric contraction of external rotation increased significantly during tDCS, and 30 and 60 minutes post-tDCS for real tDCS compared to that for sham tDCS. For internal rotation MVIC increased significantly during and 60 minutes post-tDCS. The results indicate that transcranial direct current stimulation temporarily increases maximal isometric contractions of the internal and external rotators of the shoulder in handball players. 2.

An analysis of JET fast-wave heating and current drive experiments directly related to ITER

Energy Technology Data Exchange (ETDEWEB)

Bhatnagar, V P; Eriksson, L; Gormezano, C; Jacquinot, J; Kaye, A; Start, D F.H. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

1994-07-01

The ITER fast-wave system is required to serve a variety of purposes, in particular, plasma heating to ignition, current profile and burn control and eventually, in conjunction with other schemes, a central non-inductive current drive (CD) for the steady-state operation of ITER. The ICRF heating and current drive data that has been obtained in JET are analyzed in terms of dimensionless parameters, with a view to ascertaining its direct relevance to key ITER requirements. The analysis is then used to identify areas both in physics and technological aspects of ion-cyclotron resonance heating (ICRH) and CD that require further experimentation in ITER-relevant devices such as JET to establish the required data base. (authors). 12 refs., 8 figs.

An analysis of JET fast-wave heating and current drive experiments directly related to ITER

International Nuclear Information System (INIS)

Bhatnagar, V.P.; Eriksson, L.; Gormezano, C.; Jacquinot, J.; Kaye, A.; Start, D.F.H.

1994-01-01

The ITER fast-wave system is required to serve a variety of purposes, in particular, plasma heating to ignition, current profile and burn control and eventually, in conjunction with other schemes, a central non-inductive current drive (CD) for the steady-state operation of ITER. The ICRF heating and current drive data that has been obtained in JET are analyzed in terms of dimensionless parameters, with a view to ascertaining its direct relevance to key ITER requirements. The analysis is then used to identify areas both in physics and technological aspects of ion-cyclotron resonance heating (ICRH) and CD that require further experimentation in ITER-relevant devices such as JET to establish the required data base. (authors). 12 refs., 8 figs

Direct current insulator based dielectrophoresis (DC-iDEP) microfluidic chip for blood plasma separation

OpenAIRE

Mohammadi, Mahdi

2015-01-01

Lab-on-a-Chip (LOC) integrated microfluidics has been a powerful tool for new developments in analytical chemistry. These microfluidic systems enable the miniaturization, integration and automation of complex biochemical assays through the reduction of reagent use and enabling portability.Cell and particle separation in microfluidic systems has recently gained significant attention in many sample preparations for clinical procedures. Direct-current insulator-based dielectrophoresis (DC-iDEP) ...

Effects of Transcranial Direct Current Stimulation (tDCS) on Behaviour and Electrophysiology of Language Production

Science.gov (United States)

Wirth, Miranka; Rahman, Rasha Abdel; Kuenecke, Janina; Koenig, Thomas; Horn, Helge; Sommer, Werner; Dierks, Thomas

2011-01-01

Excitatory anodal transcranial direct current stimulation (A-tDCS) over the left dorsal prefrontal cortex (DPFC) has been shown to improve language production. The present study examined neurophysiological underpinnings of this effect. In a single-blinded within-subject design, we traced effects of A-tDCS compared to sham stimulation over the left…

Las mejores prácticas aplicadas a un análisis de riesgos de seguridad de la información para las entidades financieras controladas por la Superintendencia de Economía Popular y Solidaria (Cooperativas de Ahorro y Crédito) que conforman el grupo de asistencia tecnológica Cooperativa (Asistecooper). Propuesta alternativa

OpenAIRE

Cevallos Guerra, Diego Fernando

2015-01-01

En el Ecuador, el sector financiero, como principal usuario de las tecnologías de la información y conocedor de las amenazas a las que se encuentran expuestos los diferentes servicios financieros, algunas instituciones han tenido iniciativas muy particulares para proteger la integridad, disponibilidad y confidencialidad de la información, sin embargo, se puede afirmar que estas iniciativas no han sido muy generalizadas especialmente en las cooperativas de ahorro y crédito, ante esta situación...

Transcranial direct current stimulation in obsessive-compulsive disorder: emerging clinical evidence and considerations for optimal montage of electrodes.

Science.gov (United States)

Senço, Natasha M; Huang, Yu; D'Urso, Giordano; Parra, Lucas C; Bikson, Marom; Mantovani, Antonio; Shavitt, Roseli G; Hoexter, Marcelo Q; Miguel, Eurípedes C; Brunoni, André R

2015-07-01

Neuromodulation techniques for obsessive-compulsive disorder (OCD) treatment have expanded with greater understanding of the brain circuits involved. Transcranial direct current stimulation (tDCS) might be a potential new treatment for OCD, although the optimal montage is unclear. To perform a systematic review on meta-analyses of repetitive transcranianal magnetic stimulation (rTMS) and deep brain stimulation (DBS) trials for OCD, aiming to identify brain stimulation targets for future tDCS trials and to support the empirical evidence with computer head modeling analysis. Systematic reviews of rTMS and DBS trials on OCD in Pubmed/MEDLINE were searched. For the tDCS computational analysis, we employed head models with the goal of optimally targeting current delivery to structures of interest. Only three references matched our eligibility criteria. We simulated four different electrodes montages and analyzed current direction and intensity. Although DBS, rTMS and tDCS are not directly comparable and our theoretical model, based on DBS and rTMS targets, needs empirical validation, we found that the tDCS montage with the cathode over the pre-supplementary motor area and extra-cephalic anode seems to activate most of the areas related to OCD.

Study of 2219 aluminum alloy using direct current A-TIG welding

Science.gov (United States)

Li, Hui; Zou, Jiasheng

2017-07-01

Direct current A-TIG (DCEN A-TIG) welding using special active agent had eliminated the pores and the oxidation of 2219 high-strength aluminum alloy in welding. Addition of AlF3-25% LiF active agent to DCEN A-TIG welding and arc morphology showed a trailing phenomenon. However, the change in arc morphology was not remarkable when AlF3-75% LiF active agent was added. Addition of AlF3-75% LiF active agent can refine the grain size of DCEN A-TIG joint. The mechanical properties of the weld were optimal at 10% AlF3-75% LiF active agent. Compared with AC TIG and AC A-TIG welding, DCEN A-TIG welding yielded better results for 2219 Al alloy.

¿Quiénes son los hogares que ahorran en las instituciones financieras de Nicaragua? Un análisis empírico

Directory of Open Access Journals (Sweden)

Isabel Dauner

2002-02-01

Full Text Available En Nicaragua, solamente el 5. I % de los hogares tienen una cuenta de ahorro en un banco u otra institución. Solamente 0.90/0 de los hogares "pobres" tienen una cuenta de ahorro, contra el 8.5% de los hogares "no pobres". ¿A qué se debe este bajo nivel de ahorro institucional? El presente estudio trata de responder parcialmente a esta pregunta y dar algunas pautas de cómo seguir investigando el tema. El análisis se basa en la encuesta de medición de nivel de vida (EMNV98 realizada en Nicaragua en 1998. Este artículo presenta las variables utilizadas en el modelo, plantea las hipótesis en cuanto al efecto de estas variables en la probabilidad que tiene un hogar de ser dueño de una o más cuentas de ahorro, y analiza los resultados del estudio buscando el vínculo entre ahorro y crédito institucional.

A fast fault protection based on direction of bus-side capacitor discharge current for a high-surety power supply

DEFF Research Database (Denmark)

Li, Haijin; Chen, Min; Yang, Boping

2017-01-01

A short-circuit fault protection strategy based on the direction of bus-side capacitor discharge current for a high-surety power supply, known as Super Uninterruptable Power Supply (Super UPS), is studied in this paper. It consists of multiple energy sources and storage components. All energy...... strategy is necessary to keep the uninterruptable power for the critical load. In this paper, the characteristics of the short-circuit fault are analyzed first. Then, a fast short-circuit fault locating and isolating strategy based on the direction of the discharge current of the busside capacitors...

Slow oscillating transcranial direct current stimulation during sleep has a sleep-stabilizing effect in chronic insomnia: a pilot study.

Science.gov (United States)

Saebipour, Mohammad R; Joghataei, Mohammad T; Yoonessi, Ali; Sadeghniiat-Haghighi, Khosro; Khalighinejad, Nima; Khademi, Soroush

2015-10-01

Recent evidence suggests that lack of slow-wave activity may play a fundamental role in the pathogenesis of insomnia. Pharmacological approaches and brain stimulation techniques have recently offered solutions for increasing slow-wave activity during sleep. We used slow (0.75 Hz) oscillatory transcranial direct current stimulation during stage 2 of non-rapid eye movement sleeping insomnia patients for resonating their brain waves to the frequency of sleep slow-wave. Six patients diagnosed with either sleep maintenance or non-restorative sleep insomnia entered the study. After 1 night of adaptation and 1 night of baseline polysomnography, patients randomly received sham or real stimulation on the third and fourth night of the experiment. Our preliminary results show that after termination of stimulations (sham or real), slow oscillatory transcranial direct current stimulation increased the duration of stage 3 of non-rapid eye movement sleep by 33 ± 26 min (P = 0.026), and decreased stage 1 of non-rapid eye movement sleep duration by 22 ± 17.7 min (P = 0.028), compared with sham. Slow oscillatory transcranial direct current stimulation decreased stage 1 of non-rapid eye movement sleep and wake time after sleep-onset durations, together, by 55.4 ± 51 min (P = 0.045). Slow oscillatory transcranial direct current stimulation also increased sleep efficiency by 9 ± 7% (P = 0.026), and probability of transition from stage 2 to stage 3 of non-rapid eye movement sleep by 20 ± 17.8% (P = 0.04). Meanwhile, slow oscillatory transcranial direct current stimulation decreased transitions from stage 2 of non-rapid eye movement sleep to wake by 12 ± 6.7% (P = 0.007). Our preliminary results suggest a sleep-stabilizing role for the intervention, which may mimic the effect of sleep slow-wave-enhancing drugs. © 2015 European Sleep Research Society.

Importance of the harmonics in the lighting systems for the electric energy saving; Importancia de las armonicas en el sistema de iluminacion para el ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Garibay Mendoza, V. [Lumisistemas, departamento de aseguramineto de calidad, Naucalpan (Mexico); Hernandez Bernal, J. M. [UNICORP, Mexico, D. F. (Mexico)

1995-12-31

In a lighting system the discharge lamps (fluorescent and high intensity discharge (HID)), ballast and controls are generating elements of harmonics. As a consequence of the tendency of saving energy, the use of electronic ballasts and controls that integrate dimmers, daylight and present sensors has increased in order to optimize the energy use. This paper presents the harmonics generation resulting from the fluorescent lamps operating different electronic ballasts as well as their electronic controls. Likewise, are also shown the effects caused by generation of harmonics components by the lighting system in the electric system that go from the voltage and current distortion, the presence of currents in the neutral conductor in balanced systems to the repercussions in the metering equipment such as watthour meters and the effects the lighting equipment suffer due to the presence of harmonics, such as the power factor decrease in ballasts that are of high power factor and the temperature increment in the magnetic type ballasts. [Espanol] Dentro de un sistema de iluminacion, las lamparas de descarga (fluorescentes y alta intensidad de descarga {sup H}ID{sup )}, balastros y los controles son elementos generadores de armonicas. A consecuencia de la tendencia al ahorro de energia se ha incrementado el uso de balastros electronicos y controles que integran atenuadores de luz (dimmers), sensores de luz natural y de presencia con el fin de optimizar el uso de la energia. Este trabajo presenta los resultados de generacion de armonicas para lamparas fluorescentes, operando diferentes balastros electronicos asi como con controles electronicos. Asi mismo son presentados los efectos causados por la generacion de componentes armonicas por el sistema de iluminacion dentro del sistema electrico que van desde la distorsion en voltaje y corriente, la presencia de corrientes dentro del conductor neutro en sistemas balanceados, asi como la repercusion en los equipos de medicion tales

Importance of the harmonics in the lighting systems for the electric energy saving; Importancia de las armonicas en el sistema de iluminacion para el ahorro de energia electrica

Energy Technology Data Exchange (ETDEWEB)

Garibay Mendoza, V [Lumisistemas, departamento de aseguramineto de calidad, Naucalpan (Mexico); Hernandez Bernal, J M [UNICORP, Mexico, D. F. (Mexico)

1996-12-31

In a lighting system the discharge lamps (fluorescent and high intensity discharge (HID)), ballast and controls are generating elements of harmonics. As a consequence of the tendency of saving energy, the use of electronic ballasts and controls that integrate dimmers, daylight and present sensors has increased in order to optimize the energy use. This paper presents the harmonics generation resulting from the fluorescent lamps operating different electronic ballasts as well as their electronic controls. Likewise, are also shown the effects caused by generation of harmonics components by the lighting system in the electric system that go from the voltage and current distortion, the presence of currents in the neutral conductor in balanced systems to the repercussions in the metering equipment such as watthour meters and the effects the lighting equipment suffer due to the presence of harmonics, such as the power factor decrease in ballasts that are of high power factor and the temperature increment in the magnetic type ballasts. [Espanol] Dentro de un sistema de iluminacion, las lamparas de descarga (fluorescentes y alta intensidad de descarga {sup H}ID{sup )}, balastros y los controles son elementos generadores de armonicas. A consecuencia de la tendencia al ahorro de energia se ha incrementado el uso de balastros electronicos y controles que integran atenuadores de luz (dimmers), sensores de luz natural y de presencia con el fin de optimizar el uso de la energia. Este trabajo presenta los resultados de generacion de armonicas para lamparas fluorescentes, operando diferentes balastros electronicos asi como con controles electronicos. Asi mismo son presentados los efectos causados por la generacion de componentes armonicas por el sistema de iluminacion dentro del sistema electrico que van desde la distorsion en voltaje y corriente, la presencia de corrientes dentro del conductor neutro en sistemas balanceados, asi como la repercusion en los equipos de medicion tales

Spermatogonial stem cell transplantation and male infertility: Current status and future directions.

Science.gov (United States)

Forbes, Connor M; Flannigan, Ryan; Schlegel, Peter N

2018-03-01

To summarise the current state of research into spermatogonial stem cell (SSC) therapies with a focus on future directions, as SSCs show promise as a source for preserving or initiating fertility in otherwise infertile men. We performed a search for publications addressing spermatogonial stem cell transplantation in the treatment of male infertility. The search engines PubMed and Google Scholar were used from 1990 to 2017. Search terms were relevant for spermatogonial stem cell therapies. Titles of publications were screened for relevance; abstracts were read, if related and full papers were reviewed for directly pertinent original research. In all, 58 papers were found to be relevant to this review, and were included in appropriate subheadings. This review discusses the various techniques that SSCs are being investigated to treat forms of male infertility. Evidence does not yet support clinical application of SSCs in humans. However, significant progress in the in vitro and in vivo development of SSCs, including differentiation into functional germ cells, gives reason for cautious optimism for future research.

Gestión de riesgo operativo: diseño de una metodología para su identificación y propuesta de planes de acción en cooperativas de ahorro y crédito no reguladas, miembros de una organización representativa

OpenAIRE

Sarango Tene, María Nancy

2015-01-01

La decisión de abordar como tema de tesis la “Gestión de riesgo operativo: diseño de una metodología para su identificación y propuesta de planes de acción en cooperativas de ahorro y crédito no reguladas miembros de una organización representativa”, responde a la preocupación, cada vez más acuciante, de que las cooperativas dispongan de una metodología de identificación de riesgo operativo para reducir posibles pérdidas resultantes de una mala gestión en factores de riesgo, tales como: proce...

Modeling of Pulsed Direct-Current Glow Discharge

International Nuclear Information System (INIS)

Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

2010-01-01

A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

Regenerating the human heart: direct reprogramming strategies and their current limitations.

Science.gov (United States)

Ghiroldi, Andrea; Piccoli, Marco; Ciconte, Giuseppe; Pappone, Carlo; Anastasia, Luigi

2017-10-27

Cardiovascular diseases are the leading cause of death in the Western world. Unfortunately, current therapies are often only palliative, consequently essentially making heart transplantation necessary for many patients. However, several novel therapeutic approaches in the past two decades have yielded quite encouraging results. The generation of induced pluripotent stem cells, through the forced expression of stem cell-specific transcription factors, has inspired the most promising strategies for heart regeneration by direct reprogramming of cardiac fibroblasts into functional cardiomyocytes. Initial attempts at this reprogramming were conducted using a similar approach to the one used with transcription factors, but during years, novel strategies have been tested, e.g., miRNAs, recombinant proteins and chemical molecules. Although preliminary results on animal models are promising, the low reprogramming efficiency, as well as the incomplete maturation of the cardiomyocytes, still represents important obstacles. This review covers direct transdifferentiation strategies that have been proposed and developed and illustrates the pros and cons of each approach. Indeed, as described in the manuscript, there are still many unanswered questions and drawbacks that require a better understanding of the basic signaling pathways and transcription factor networks before functional cells, suitable for cardiac regeneration and safe for the patients, can be generated and used for human therapies.

Notes on Human Trials of Transcranial Direct Current Stimulation between 1960 and 1998

Science.gov (United States)

Esmaeilpour, Zeinab; Schestatsky, Pedro; Bikson, Marom; Brunoni, André R.; Pellegrinelli, Ada; Piovesan, Fernanda X.; Santos, Mariana M. S. A.; Menezes, Renata B.; Fregni, Felipe

2017-01-01

Background: Transcranial direct current stimulation (tDCS) is investigated to modulate neuronal function including cognitive neuroscience and neuropsychiatric therapies. While cases of human stimulation with rudimentary batteries date back more than 200 years, clinical trials with current controlled stimulation were published intermittently since the 1960s. The modern era of tDCS only started after 1998. Objectives: To review methods and outcomes of tDCS studies from old literature (between 1960 and 1998) with intention of providing new insight for ongoing tDCS trials and development of tDCS protocols especially for the purpose of treatment. Methods: Articles were identified through a search in PubMed and through the reference list from its selected articles. We included only non-invasive human studies that provided controlled direct current and were written in English, French, Spanish or Portuguese before the year of 1998, the date in which modern stimulation paradigms were implemented. Results: Fifteen articles met our criteria. The majority were small-randomized controlled clinical trials that enrolled a mean of approximately 26 subjects (Phase II studies). Most of the studies (around 83%) assessed the role of tDCS in the treatment of psychiatric conditions, in which the main outcomes were measured by means of behavioral scales and clinical observation, but the diagnostic precision and the quality of outcome monitoring, including adverse events, were deficient by modern standards. Compared to modern tDCS dose, the stimulation intensities used (0.1–1 mA) were lower, however as the electrodes were typically smaller (e.g., 1.26 cm2), the average electrode current density (0.2 mA/cm2) was approximately 4× higher. The number of sessions ranged from one to 120 (median 14). Notably, the stimulation session durations of several minutes to 11 h (median 4.5 h) could markedly exceed modern tDCS protocols. Twelve studies out of 15 showed positive results. Only mild side

Direct-Current Forced Interruption and Breaking Performance of Spiral-Type Contacts in Aero Applications

Directory of Open Access Journals (Sweden)

Wenlei Huo

2017-05-01

Full Text Available This paper analyses the transient characteristics and breaking performance of direct-current (DC forced-interruption vacuum interrupters in 270 V power-supply systems. Three stages are identified in forced interruption: the DC-arcing stage, current-commutation stage, and voltage-recovery stage. During the current-commutation stage, the reverse peak-current coefficient k, which is a key design factor, is used to calculate the rate of current at zero-crossing (di/dt. MATLAB/Simulink simulation models are established to obtain the transient characteristics influenced by the forced-commutation branch parameters and the coefficient k. To study the breaking performance of spiral-type contacts, experiments are conducted for different contact materials and arcing times for currents less than 3.5 kA. During the DC-arcing stage, a locally intensive burning arc is observed in the CuW80 contact; however, it is not observed in the CuCr50 contact. On examining the re-ignition interruption results of the CuW80 contact, the intensive burning arc is found to be positioned within a possible re-ignition region. When the arcing time is longer than 1 ms, the intensive burning arc occurs and affects the breaking performance of the spiral-type contacts. If the DC-arcing stage is prolonged, the total arcing energy increases, which leads to a lower breaking capacity.

Effects of Dual Transcranial Direct Current Stimulation for Aphasia in Chronic Stroke Patients

OpenAIRE

Lee, Seung Yeol; Cheon, Hee-Jung; Yoon, Kyoung Jae; Chang, Won Hyuk; Kim, Yun-Hee

2013-01-01

Objective To investigate any additional effect of dual transcranial direct current stimulation (tDCS) compared with single tDCS in chronic stroke patients with aphasia. Methods Eleven chronic stroke patients (aged 52.6?13.4 years, nine men) with aphasia were enrolled. Single anodal tDCS was applied over the left inferior frontal gyrus (IFG) and a cathodal electrode was placed over the left buccinator muscle. Dual tDCS was applied as follows: 1) anodal tDCS over the left IFG and cathodal tDCS ...

Effect of transcranial direct current stimulation on vestibular-ocular and vestibulo-perceptual thresholds.

Science.gov (United States)

Kyriakareli, Artemis; Cousins, Sian; Pettorossi, Vito E; Bronstein, Adolfo M

2013-10-02

Transcranial direct current stimulation (tDCS) was used in 17 normal individuals to modulate vestibulo-ocular reflex (VOR) and self-motion perception rotational thresholds. The electrodes were applied over the temporoparietal junction bilaterally. Both vestibular nystagmic and perceptual thresholds were increased during as well as after tDCS stimulation. Body rotation was labeled as ipsilateral or contralateral to the anode side, but no difference was observed depending on the direction of rotation or hemisphere polarity. Threshold increase during tDCS was greater for VOR than for motion perception. 'Sham' stimulation had no effect on thresholds. We conclude that tDCS produces an immediate and sustained depression of cortical regions controlling VOR and movement perception. Temporoparietal areas appear to be involved in vestibular threshold modulation but the differential effects observed between VOR and perception suggest a partial dissociation between cortical processing of reflexive and perceptual responses.

Direct and pulsed current annealing of p-MOSFET based dosimeter: the "MOSkin".

Science.gov (United States)

Alshaikh, Sami; Carolan, Martin; Petasecca, Marco; Lerch, Michael; Metcalfe, Peter; Rosenfeld, Anatoly

2014-06-01

Contemporary radiation therapy (RT) is complicated and requires sophisticated real-time quality assurance (QA). While 3D real-time dosimetry is most preferable in RT, it is currently not fully realised. A small, easy to use and inexpensive point dosimeter with real-time and in vivo capabilities is an option for routine QA. Such a dosimeter is essential for skin, in vivo or interface dosimetry in phantoms for treatment plan verification. The metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector is one of the best choices for these purposes, however, the MOSFETs sensitivity and its signal stability degrade after essential irradiation which limits its lifespan. The accumulation of positive charge on the gate oxide and the creation of interface traps near the silicon-silicon dioxide layer is the primary physical phenomena responsible for this degradation. The aim of this study is to investigate MOSFET dosimeter recovery using two proposed annealing techniques: direct current (DC) and pulsed current (PC), both based on hot charged carrier injection into the gate oxide of the p-MOSFET dosimeter. The investigated MOSFETs were reused multiple times using an irradiation-annealing cycle. The effect of the current-annealing parameters was investigated for the dosimetric characteristics of the recovered MOSFET dosimeters such as linearity, sensitivity and initial threshold voltage. Both annealing techniques demonstrated excellent results in terms of maintaining a stable response, linearity and sensitivity of the MOSFET dosimeter. However, PC annealing is more preferable than DC annealing as it offers better dose response linearity of the reused MOSFET and has a very short annealing time.

Universal "Imaginary Closed Circuit Method" and Formula for Determination of Direction of Induced EMF/Current

Science.gov (United States)

Atram, Dattatraya Balaram

2011-01-01

Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different…

Culture, mind, and the brain: current evidence and future directions.

Science.gov (United States)

Kitayama, Shinobu; Uskul, Ayse K

2011-01-01

Current research on culture focuses on independence and interdependence and documents numerous East-West psychological differences, with an increasing emphasis placed on cognitive mediating mechanisms. Lost in this literature is a time-honored idea of culture as a collective process composed of cross-generationally transmitted values and associated behavioral patterns (i.e., practices). A new model of neuro-culture interaction proposed here addresses this conceptual gap by hypothesizing that the brain serves as a crucial site that accumulates effects of cultural experience, insofar as neural connectivity is likely modified through sustained engagement in cultural practices. Thus, culture is "embrained," and moreover, this process requires no cognitive mediation. The model is supported in a review of empirical evidence regarding (a) collective-level factors involved in both production and adoption of cultural values and practices and (b) neural changes that result from engagement in cultural practices. Future directions of research on culture, mind, and the brain are discussed.

Adaptive threshold hunting for the effects of transcranial direct current stimulation on primary motor cortex inhibition.

Science.gov (United States)

Mooney, Ronan A; Cirillo, John; Byblow, Winston D

2018-06-01

Primary motor cortex excitability can be modulated by anodal and cathodal transcranial direct current stimulation (tDCS). These neuromodulatory effects may, in part, be dependent on modulation within gamma-aminobutyric acid (GABA)-mediated inhibitory networks. GABAergic function can be quantified non-invasively using adaptive threshold hunting paired-pulse transcranial magnetic stimulation (TMS). The previous studies have used TMS with posterior-anterior (PA) induced current to assess tDCS effects on inhibition. However, TMS with anterior-posterior (AP) induced current in the brain provides a more robust measure of GABA-mediated inhibition. The aim of the present study was to assess the modulation of corticomotor excitability and inhibition after anodal and cathodal tDCS using TMS with PA- and AP-induced current. In 16 young adults (26 ± 1 years), we investigated the response to anodal, cathodal, and sham tDCS in a repeated-measures double-blinded crossover design. Adaptive threshold hunting paired-pulse TMS with PA- and AP-induced current was used to examine separate interneuronal populations within M1 and their influence on corticomotor excitability and short- and long-interval inhibition (SICI and LICI) for up to 60 min after tDCS. Unexpectedly, cathodal tDCS increased corticomotor excitability assessed with AP (P = 0.047) but not PA stimulation (P = 0.74). SICI AP was reduced after anodal tDCS compared with sham (P = 0.040). Pearson's correlations indicated that SICI AP and LICI AP modulation was associated with corticomotor excitability after anodal (P = 0.027) and cathodal tDCS (P = 0.042). The after-effects of tDCS on corticomotor excitability may depend on the direction of the TMS-induced current used to make assessments, and on modulation within GABA-mediated inhibitory circuits.

Using transcranial direct-current stimulation (tDCS) to understand cognitive processing.

Science.gov (United States)

Reinhart, Robert M G; Cosman, Josh D; Fukuda, Keisuke; Woodman, Geoffrey F

2017-01-01

Noninvasive brain stimulation methods are becoming increasingly common tools in the kit of the cognitive scientist. In particular, transcranial direct-current stimulation (tDCS) is showing great promise as a tool to causally manipulate the brain and understand how information is processed. The popularity of this method of brain stimulation is based on the fact that it is safe, inexpensive, its effects are long lasting, and you can increase the likelihood that neurons will fire near one electrode and decrease the likelihood that neurons will fire near another. However, this method of manipulating the brain to draw causal inferences is not without complication. Because tDCS methods continue to be refined and are not yet standardized, there are reports in the literature that show some striking inconsistencies. Primary among the complications of the technique is that the tDCS method uses two or more electrodes to pass current and all of these electrodes will have effects on the tissue underneath them. In this tutorial, we will share what we have learned about using tDCS to manipulate how the brain perceives, attends, remembers, and responds to information from our environment. Our goal is to provide a starting point for new users of tDCS and spur discussion of the standardization of methods to enhance replicability.

Food waste-to-energy conversion technologies: current status and future directions.

Science.gov (United States)

Pham, Thi Phuong Thuy; Kaushik, Rajni; Parshetti, Ganesh K; Mahmood, Russell; Balasubramanian, Rajasekhar

2015-04-01

Food waste represents a significantly fraction of municipal solid waste. Proper management and recycling of huge volumes of food waste are required to reduce its environmental burdens and to minimize risks to human health. Food waste is indeed an untapped resource with great potential for energy production. Utilization of food waste for energy conversion currently represents a challenge due to various reasons. These include its inherent heterogeneously variable compositions, high moisture contents and low calorific value, which constitute an impediment for the development of robust, large scale, and efficient industrial processes. Although a considerable amount of research has been carried out on the conversion of food waste to renewable energy, there is a lack of comprehensive and systematic reviews of the published literature. The present review synthesizes the current knowledge available in the use of technologies for food-waste-to-energy conversion involving biological (e.g. anaerobic digestion and fermentation), thermal and thermochemical technologies (e.g. incineration, pyrolysis, gasification and hydrothermal oxidation). The competitive advantages of these technologies as well as the challenges associated with them are discussed. In addition, the future directions for more effective utilization of food waste for renewable energy generation are suggested from an interdisciplinary perspective. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of alternating and direct electrical current application on the odontoblastic layer in human teeth : an in vitro study

NARCIS (Netherlands)

Alwas-Danowska, HM; Huysmans, MCDNJM; Verdonschot, EH

Aim The aim of this study was to investigate the influence of a low intensity alternating current on the odontoblasts and odontoblast layer and compare this with the effects of a direct current. Methodology Teeth extracted for orthodontic were immersed in physiological saline stabilized with thymol

Suspended sediment dynamics in a large-scale turbidity current: Direct measurements from the deep-water Congo Canyon

Science.gov (United States)

Simmons, S.; Azpiroz, M.; Cartigny, M.; Clare, M. A.; Parsons, D. R.; Sumner, E.; Talling, P. J.

2016-12-01

Turbidity currents that transport sediment to the deep ocean deposit a greater volume of sediment than any other process on Earth. To date, only a handful of studies have directly measured turbidity currents, with flow durations ranging from a few minutes to a few hours. Our understanding of turbidity current dynamics is therefore largely derived from scaled laboratory experiments and numerical modelling. Recent years have seen the first field-scale measurements of depth-resolved velocity profiles, but sediment concentration (a key parameter for turbidity currents) remains elusive. Here, we present high resolution measurements of deep-water turbidity currents from the Congo Canyon; one of the world's largest submarine canyons. Direct measurements using acoustic Doppler current profilers (ADCPs) show that flows can last for many days, rather than hours as seen elsewhere, and provide the first quantification of concentration and grain size within deep-water turbidity currents.Velocity and backscatter were measured at 5 second intervals by an ADCP suspended 80 m above the canyon floor, at 2000 m water depth. A novel inversion method using multiple ADCP frequencies enabled quantification of sediment concentration and grain size within the flows. We identify high concentrations of coarse sediment within a thin frontal cell, which outruns a thicker, trailing body. Thus, the flows grow in length while propagating down-canyon. This is distinct from classical models and other field-scale measurements of turbidity currents. The slow-moving body is dominated by suspended fine-grained sediment. The body mixes with the surrounding fluid leaving diffuse clouds of sediment that persist for days after initial entrainment. Ambient tidal flow also controls the mixing within the body and the surrounding fluid. Our results provide a new quantification of suspended sediment within flows and the interaction with the surrounding fluid.

Current direction, temperature, and other data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 1979-05-15 to 1980-03-22 (NODC Accession 8000457)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, current direction, and other data were collected using moored current meter casts from the EXCELLENCE in the Gulf of Mexico from May 15, 1979...

Clinical effectiveness of primary and secondary headache treatment by transcranial direct current stimulation

Directory of Open Access Journals (Sweden)

Dmitry ePinchuk

2013-03-01

Full Text Available The clinical effectiveness of headache treatment by transcranial direct current stimulation with various locations of stimulating electrodes on the scalp was analyzed retrospectively. The results of the treatment were analyzed in 90 patients aged from 19 to 54 years (48 patients had migraine without aura, 32 – frequent episodic tension-type headaches, 10 – chronic tension-type headaches and in 44 adolescents aged 11 – 16 years with chronic posttraumatic headaches after a mild head injury. Clinical effectiveness of tDCS with 70 – 150 µA current for 30 – 45 minutes via 6.25 cm2 stimulating electrodes is comparable to that of modern pharmacological drugs, with no negative side effects. The obtained result has been maintained on average from 5 to 9 months. It has been demonstrated that effectiveness depends on localization of stimulating electrodes used for different types of headaches.

Transcranial Direct Current Stimulation (tDCS): A Promising Treatment for Major Depressive Disorder?

Science.gov (United States)

Bennabi, Djamila; Haffen, Emmanuel

2018-01-01

Background: Transcranial direct current stimulation (tDCS) opens new perspectives in the treatment of major depressive disorder (MDD), because of its ability to modulate cortical excitability and induce long-lasting effects. The aim of this review is to summarize the current status of knowledge regarding tDCS application in MDD. Methods: In this review, we searched for articles published in PubMed/MEDLINE from the earliest available date to February 2018 that explored clinical and cognitive effects of tDCS in MDD. Results: Despite differences in design and stimulation parameters, the examined studies indicated beneficial effects of tDCS for MDD. These preliminary results, the non-invasiveness of tDCS, and its good tolerability support the need for further research on this technique. Conclusions: tDCS constitutes a promising therapeutic alternative for patients with MDD, but its place in the therapeutic armamentarium remains to be determined. PMID:29734768

Effects of transcranial direct current stimulation over left dorsolateral pFC on the attentional blink depend on individual baseline performance

NARCIS (Netherlands)

London, R.E.; Slagter, H.A.

2015-01-01

Selection mechanisms that dynamically gate only relevant perceptual information for further processing and sustained representation in working memory are critical for goal-directed behavior. We examined whether this gating process can be modulated by anodal transcranial direct current stimulation

Research on corrosion mechanism of suspension insulator steel foot of direct current system and measures for corrosion inhibition

Science.gov (United States)

Chen, He; Yang, Yueguang; Su, Guolei; Wang, Xiaoqing; Zhang, Hourong; Sun, Xiaoyu; Fan, Youping

2017-09-01

There are increasingly serious electrocorrosion phenomena on insulator hardware caused by direct current transmission due to the wide-range popularization of extra high voltage direct current transmission engineering in our country. Steel foot corrosion is the main corrosion for insulators on positive polarity side of transmission lines. On one hand, the corrosion leads to the tapering off of steel foot diameter, having a direct influence on mechanical property of insulators; on the other hand, in condition of corrosion on steel foot wrapped in porcelain ware, the volume of the corrosion product is at least 50% more than that of the original steel foot, leading to bursting of porcelain ware, threatening safe operation of transmission lines. Therefore, it is necessary to conduct research on the phenomenon and propose feasible measures for corrosion inhibition. Starting with the corrosion mechanism, this article proposes two measures for corrosion inhibition, and verifies the inhibition effect in laboratory conditions, providing reference for application in engineering.

Direct Current as an Integrating Platform for ZNE Buildings with EVs and Storage: DC Direct Systems – A Bridge to a Low Carbon Future?

Energy Technology Data Exchange (ETDEWEB)

Johnson, Karl [California Inst. for Energy and the Environment, Berkeley, CA (United States); Vossos, Vagelis [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kloss, Margarita [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Robinson, Gerald [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Rich [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-09-01

Cost effective zero net energy (ZNE) schemes exist for many types of residential and commercial buildings. Yet, today’s alternating current (AC) based ZNE designs may be as much as 10% to 20% less efficient, more costly, and more complicated than a design based on direct current (DC) technologies. An increasing number of research organizations and manufacturers are just starting the process of developing products and conducting research and development (R&D) efforts. These early R&D efforts indicate that the use of DC technologies may deliver many energy and non-energy benefits relative to AC-based typologies. DC ZNE schemes may provide for an ideal integrating platform for natively DC-based onsite generation, storage, electric vehicle (EV) charging and end-use loads. Emerging empirical data suggest that DC end-use appliances are more efficient, simpler, more durable, and lower cost. DC technologies appear to provide ratepayers a lower cost pathway to achieve resilient ZNE buildings, and simultaneously yield a plethora of benefits. This paper draws from the current research effort entitled "Direct Current as an Integrating and Enabling Platform," co-led by the Lawrence Berkeley National Laboratory (LBNL), the California Institute for Energy and the Environment (CIEE), the Electric Power Research Institute (EPRI) and funded under the California Energy Commission’s Energy Program Investment Charge (CEC EPIC). The first phase of this EPIC research is focused on assembling and summarizing known global performance information on DC and DC-AC hybrid end-use appliances and power systems. This paper summarizes the information and insights gained from this research effort.

Current direction, temperature, and salinity data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 1983-08-31 to 1984-10-01 (NODC Accession 8500021)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, temperature, and salinity data were collected using moored current meter casts in the Gulf of Mexico from August 31, 1983 to October 1, 1984. Data...

Current frontiers and future directions of telecoupling research

Science.gov (United States)

Liu, J.

2016-12-01

The world has been increasingly interconnected over long distances though processes such as international trade, migration, telecommunication, and disease spread. However, previous studies often focused on socioeconomic or environmental issues of distant processes. While these studies have generated useful information for individual disciplines, integrating socioeconomic and environmental information is essential for holistic understanding of complex global challenges and unbiased decision making to address the challenges. To advance integrated research, the framework of telecoupling (socioeconomic and environmental interactions over distances) has been developed to explicitly address both socioeconomic and environmental issues simultaneously. Although the framework is relatively new, it has already been applied to tackle a variety of globally important issues, such as food security, water resources, energy sustainability, land use, international trade (e.g., food, forest products, energy, wildlife, industrial products), species invasion, investment, ecosystem services, conservation, information dissemination, and tourism. These applications have identified many important research gaps (e.g. spillover systems) and hidden linkages (e.g. feedbacks) among distant areas of the world with profound implications for sustainable development, ecosystem health, and human well-being. While working with telecoupling presents more challenges than focusing only on disciplinary issues, support from funding agencies has helped accelerate research on telecoupling and more efforts are being aimed at framework quantification and operationalization. The presenter will provide an overview of the current frontiers, discuss future research directions, and highlight emerging opportunities and challenges in telecoupling research and governance.

Energy saving in buildings through the elimination of typical problems; Ahorro de energia electrica en edificios a traves de la eliminacion de problemas tipicos

Energy Technology Data Exchange (ETDEWEB)

Ramirez Rivero, Alex G [Genertek, S. A. de C. V., Mexico, D. F. (Mexico)

1994-12-31

The enormous electric energy consumption in buildings represents an important area of saving opportunities. The design of installations without advanced technical illumination criteria, the absence of standardization over energy efficiency, the lack of observation of the existing standards and guides, the continuous load growth in existing installations and the lack of appropriate maintenance, are some of the causes of the inefficient use of electric energy in buildings. Although the problems, and consequently the solutions, are exclusive for each unit, some of the former are frequently repeated. In this paper the problems found along more than 40 audits conducted in large buildings of different types in Mexico city are commented. [Espanol] El enorme consumo de energia electrica en edificios representa una importante area de oportunidad para ahorro. El diseno de instalaciones sin criterios luminotecnicos avanzados, la ausencia de normalizacion sobre eficiencia energetica, la falta de observancia de las normas y recomendaciones vigentes, el continuo crecimiento de carga en instalaciones existentes y la falta de mantenimiento adecuado son algunas de las causas del uso ineficiente de la energia electrica en inmuebles. Aunque los problemas y por tanto las soluciones son particulares para cada unidad, algunos de los primeros se repiten frecuentemente. En este trabajo se comentan los problemas encontrados a lo largo de mas de 40 auditorias realizadas a inmuebles grandes de diversos tipos en la ciudad de Mexico.

Energy saving in buildings through the elimination of typical problems; Ahorro de energia electrica en edificios a traves de la eliminacion de problemas tipicos

Energy Technology Data Exchange (ETDEWEB)

Ramirez Rivero, Alex G. [Genertek, S. A. de C. V., Mexico, D. F. (Mexico)

1993-12-31

The enormous electric energy consumption in buildings represents an important area of saving opportunities. The design of installations without advanced technical illumination criteria, the absence of standardization over energy efficiency, the lack of observation of the existing standards and guides, the continuous load growth in existing installations and the lack of appropriate maintenance, are some of the causes of the inefficient use of electric energy in buildings. Although the problems, and consequently the solutions, are exclusive for each unit, some of the former are frequently repeated. In this paper the problems found along more than 40 audits conducted in large buildings of different types in Mexico city are commented. [Espanol] El enorme consumo de energia electrica en edificios representa una importante area de oportunidad para ahorro. El diseno de instalaciones sin criterios luminotecnicos avanzados, la ausencia de normalizacion sobre eficiencia energetica, la falta de observancia de las normas y recomendaciones vigentes, el continuo crecimiento de carga en instalaciones existentes y la falta de mantenimiento adecuado son algunas de las causas del uso ineficiente de la energia electrica en inmuebles. Aunque los problemas y por tanto las soluciones son particulares para cada unidad, algunos de los primeros se repiten frecuentemente. En este trabajo se comentan los problemas encontrados a lo largo de mas de 40 auditorias realizadas a inmuebles grandes de diversos tipos en la ciudad de Mexico.

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization.

Science.gov (United States)

Zhang, H-S; Komvopoulos, K

2008-07-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp3) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization

International Nuclear Information System (INIS)

Zhang, H.-S.; Komvopoulos, K.

2008-01-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp 3 ) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study

Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharge: Part I. Experimental

NARCIS (Netherlands)

Gielen, J.W.A.M.; de Groot, S.; Dijk, van J.; Mullen, van der J.J.A.M.

2004-01-01

Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally,

Current direction, wind wave spectra, and CTD data from moored current meter and CTD casts in the North Atlantic Ocean from 1982-09-15 to 1983-09-15 (NODC Accession 8500148)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, wind wave spectra, and CTD data were collected using moored current meter and CTD casts in the Gulf of Mexico from September 3, 1982 to September...

High magnetic field science and its application in the United States current status and future directions

CERN Document Server

National Research Council of the National Academies

2013-01-01

The Committee to Assess the Current Status and Future Direction of High Magnetic Field Science in the United States was convened by the National Research Council in response to a request by the National Science Foundation. This report answers three questions: (1) What is the current state of high-field magnet science, engineering, and technology in the United States, and are there any conspicuous needs to be addressed? (2) What are the current science drivers and which scientific opportunities and challenges can be anticipated over the next ten years? (3) What are the principal existing and planned high magnetic field facilities outside of the United States, what roles have U.S. high field magnet development efforts played in developing those facilities, and what potentials exist for further international collaboration in this area? A magnetic field is produced by an electrical current in a metal coil. This current exerts an expansive force on the coil, and a magnetic field is "high" if it challenges the str...

College Advising: Current Perceptions, Future Directions.

Science.gov (United States)

Chapman, David W.; Gill, Stephen J.

1981-01-01

Examines the college admissions activities that high school counselors believe are most effective in providing accurate information to students. Also examines the current role of the counselor in college advising and reports on what counselors predict will be the trends in college advising. (Author/RC)

Cellular Mechanisms of Transcranial Direct Current Stimulation

Science.gov (United States)

2016-07-14

fEPSP responses are significantly (P < 0.05, *) facilitated with +8 V/m fields ( left ) and reduced with -8 V/m ( right ) in three pathways. In each...cortex results in a sustained modulation of synaptic efficacy. A) Schematic of anodal ( left ) and cathodal ( right ) DCS with current flow along the...current stimulation (tDCS) delivered 1day vs . 1week after cerebral ischemia in rats. Brain Res. Zimerman M, Nitsch M, Giraux P, Gerloff C, Cohen LG

Investigación de los índices de gestión de las cooperativas de ahorro y crédito del cantón Ambato, y propuesta de mejora en los procesos internos de la satisfacción del cliente para el año 2012.

OpenAIRE

Guerrero López, Juliana Lissette; Manobanda Pinto, Christian Fernando

2013-01-01

Las cooperativas de ahorro y crédito reguladas por la Superintendencia de Bancos y Seguros de la ciudad de Ambato tienen como objetivo primordial el servir a la comunidad a través de la prestación de servicios financieros de los más altos estándares de calidad; comprometidos con el desarrollo socio económico del país. La presente investigación se realizó durante el año 2012 cuyo propósito fue investigar los índices de gestión y diseñar una propuesta de mejora en los procesos internos de la sa...

Imaging transcranial direct current stimulation (tDCS) of the prefrontal cortex-correlation or causality in stimulation-mediated effects?

Science.gov (United States)

Wörsching, Jana; Padberg, Frank; Ertl-Wagner, Birgit; Kumpf, Ulrike; Kirsch, Beatrice; Keeser, Daniel

2016-10-01

Transcranial current stimulation approaches include neurophysiologically distinct non-invasive brain stimulation techniques widely applied in basic, translational and clinical research: transcranial direct current stimulation (tDCS), oscillating transcranial direct current stimulation (otDCS), transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). Prefrontal tDCS seems to be an especially promising tool for clinical practice. In order to effectively modulate relevant neural circuits, systematic research on prefrontal tDCS is needed that uses neuroimaging and neurophysiology measures to specifically target and adjust this method to physiological requirements. This review therefore analyses the various neuroimaging methods used in combination with prefrontal tDCS in healthy and psychiatric populations. First, we provide a systematic overview on applications, computational models and studies combining neuroimaging or neurophysiological measures with tDCS. Second, we categorise these studies in terms of their experimental designs and show that many studies do not vary the experimental conditions to the extent required to demonstrate specific relations between tDCS and its behavioural or neurophysiological effects. Finally, to support best-practice tDCS research we provide a methodological framework for orientation among experimental designs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-commutated high-voltage direct current transmission with DC circuit breakers. Backbone for the energy policy turnaround; Selbstgefuehrte Hochspannungs-Gleichstromuebertragung mit DC-Leistungsschalter. Rueckgrat fuer die Energiewende

Energy Technology Data Exchange (ETDEWEB)

Goerner, Raphael [ABB AG, Mannheim (Germany). Marketing und Vertrieb, Geschaeftsbereich Grid Systems

2013-06-01

The 'current war' between direct current and alternating current is extended by a new location. In the future, both technologies work together in order to provide a reliable power transmission in Germany and long-term in Europe. This is based on the self-guided high-voltage direct current transmission. In conjunction with direct current circuit breakers (DC circuit breaker) the power circuit breakers may help to make the transmission grids more flexible and to minimize losses.

Energy saving: optimal use of air conditioning equipment by means of the solar control; Ahorro de energia: uso optimo de los acondicionadores de aire mediante el control solar

Energy Technology Data Exchange (ETDEWEB)

Mejia D, David; Morillon G, David; Rodriguez V, Luis [Universidad Nacional Autonoma de Mexico (Mexico)

2001-09-01

In this article the evaluation of the solar heat gains through the transparent parts of a building (houses of social interest) is presented; with the purpose of determining the heat gains through windows during summer time and under the following conditions: without solar protection, with the use of eaves, solar breakers and, finally, with the use of both elements. With the determined percentage of the diminution of heat gains, the considered potential of energy saving in air conditioning was obtained that would be available if the houses were constructed with solar control. [Spanish] En este articulo se presenta la evaluacion de las ganancias de calor solar a traves de las partes transparentes de un edificio (viviendas de interes social); con el objeto de determinar las ganancias de calor a traves de ventanas para la epoca de verano y bajo las siguientes condiciones: sin proteccion solar, con el empleo de aleros, con quiebrasoles y, finalmente, con el empleo de ambos elementos. Con el porcentaje determinado de la disminucion de ganancias de calor, se obtuvo el potencial estimado de ahorro de energia en aire acondicionado que se tendria si las viviendas se construyen con control solar.

Spermatogonial stem cell transplantation and male infertility: Current status and future directions

Directory of Open Access Journals (Sweden)

Connor M. Forbes

2018-03-01

Full Text Available Objective: To summarise the current state of research into spermatogonial stem cell (SSC therapies with a focus on future directions, as SSCs show promise as a source for preserving or initiating fertility in otherwise infertile men. Materials and methods: We performed a search for publications addressing spermatogonial stem cell transplantation in the treatment of male infertility. The search engines PubMed and Google Scholar were used from 1990 to 2017. Search terms were relevant for spermatogonial stem cell therapies. Titles of publications were screened for relevance; abstracts were read, if related and full papers were reviewed for directly pertinent original research. Results: In all, 58 papers were found to be relevant to this review, and were included in appropriate subheadings. This review discusses the various techniques that SSCs are being investigated to treat forms of male infertility. Conclusions: Evidence does not yet support clinical application of SSCs in humans. However, significant progress in the in vitro and in vivo development of SSCs, including differentiation into functional germ cells, gives reason for cautious optimism for future research. Keywords: Non-obstructive azoospermia, Fertility preservation, Onco-fertility, Male infertility, Stem cell therapy, Allograft

Transcranial Direct Current Stimulation (tDCS: A Beginner's Guide for Design and Implementation

Directory of Open Access Journals (Sweden)

Hayley Thair

2017-11-01

Full Text Available Transcranial direct current stimulation (tDCS is a popular brain stimulation method that is used to modulate cortical excitability, producing facilitatory or inhibitory effects upon a variety of behaviors. There is, however, a current lack of consensus between studies, with many results suggesting that polarity-specific effects are difficult to obtain. This article explores some of these differences and highlights the experimental parameters that may underlie their occurrence. We provide a general, practical snapshot of tDCS methodology, including what it is used for, how to use it, and considerations for designing an effective and safe experiment. Our aim is to equip researchers who are new to tDCS with the essential knowledge so that they can make informed and well-rounded decisions when designing and running successful experiments. By summarizing the varied approaches, stimulation parameters, and outcomes, this article should help inform future tDCS research in a variety of fields.

Transcranial Direct Current Stimulation (tDCS): A Beginner's Guide for Design and Implementation

Science.gov (United States)

Thair, Hayley; Holloway, Amy L.; Newport, Roger; Smith, Alastair D.

2017-01-01

Transcranial direct current stimulation (tDCS) is a popular brain stimulation method that is used to modulate cortical excitability, producing facilitatory or inhibitory effects upon a variety of behaviors. There is, however, a current lack of consensus between studies, with many results suggesting that polarity-specific effects are difficult to obtain. This article explores some of these differences and highlights the experimental parameters that may underlie their occurrence. We provide a general, practical snapshot of tDCS methodology, including what it is used for, how to use it, and considerations for designing an effective and safe experiment. Our aim is to equip researchers who are new to tDCS with the essential knowledge so that they can make informed and well-rounded decisions when designing and running successful experiments. By summarizing the varied approaches, stimulation parameters, and outcomes, this article should help inform future tDCS research in a variety of fields. PMID:29213226

Transcranial direct current stimulation (tDCS) for treatment of major depression during pregnancy: study protocol for a pilot randomized controlled trial.

Science.gov (United States)

Vigod, Simone; Dennis, Cindy-Lee; Daskalakis, Zafiris; Murphy, Kellie; Ray, Joel; Oberlander, Tim; Somerton, Sarah; Hussain-Shamsy, Neesha; Blumberger, Daniel

2014-09-18

Women with depression in pregnancy are faced with difficult treatment decisions. Untreated, antenatal depression has serious negative implications for mothers and children. While antidepressant drug treatment is likely to improve depressive symptoms, it crosses the placenta and may pose risks to the unborn child. Transcranial direct current stimulation is a focal brain stimulation treatment that improves depressive symptoms within 3 weeks of treatment by inducing changes to brain areas involved in depression, without impacting any other brain areas, and without inducing changes to heart rate, blood pressure or core body temperature. The localized nature of transcranial direct current stimulation makes it an ideal therapeutic approach for treating depression during pregnancy, although it has never previously been evaluated in this population. We describe a pilot randomized controlled trial of transcranial direct current stimulation among women with depression in pregnancy to assess the feasibility of a larger, multicentre efficacy study. Women over 18 years of age and between 14 and 32 weeks gestation can be enrolled in the study provided they meet diagnostic criteria for a major depressive episode of at least moderate severity and have been offered but refused antidepressant medication. Participants are randomized to receive active transcranial direct current stimulation or a sham condition that is administered in 15 30-minute treatments over three weeks. Women sit upright during treatment and receive obstetrical monitoring prior to, during and after each treatment session. Depressive symptoms, treatment acceptability, and pregnancy outcomes are assessed at baseline (prior to randomization), at the end of each treatment week, every four weeks post-treatment until delivery, and at 4 and 12 weeks postpartum. Transcranial direct current stimulation is a novel therapeutic option for treating depression during pregnancy. This protocol allows for assessment of the

Top-Down Effect of Direct Current Stimulation on the Nociceptive Response of Rats.

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Luiz Fabio Dimov

Full Text Available Transcranial direct current stimulation (tDCS is an emerging, noninvasive technique of neurostimulation for treating pain. However, the mechanisms and pathways involved in its analgesic effects are poorly understood. Therefore, we investigated the effects of direct current stimulation (DCS on thermal and mechanical nociceptive thresholds and on the activation of the midbrain periaqueductal gray (PAG and the dorsal horn of the spinal cord (DHSC in rats; these central nervous system areas are associated with pain processing. Male Wistar rats underwent cathodal DCS of the motor cortex and, while still under stimulation, were evaluated using tail-flick and paw pressure nociceptive tests. Sham stimulation and naive rats were used as controls. We used a randomized design; the assays were not blinded to the experimenter. Immunoreactivity of the early growth response gene 1 (Egr-1, which is a marker of neuronal activation, was evaluated in the PAG and DHSC, and enkephalin immunoreactivity was evaluated in the DHSC. DCS did not change the thermal nociceptive threshold; however, it increased the mechanical nociceptive threshold of both hind paws compared with that of controls, characterizing a topographical effect. DCS decreased the Egr-1 labeling in the PAG and DHSC as well as the immunoreactivity of spinal enkephalin. Altogether, the data suggest that DCS disinhibits the midbrain descending analgesic pathway, consequently inhibiting spinal nociceptive neurons and causing an increase in the nociceptive threshold. This study reinforces the idea that the motor cortex participates in the neurocircuitry that is involved in analgesia and further clarifies the mechanisms of action of tDCS in pain treatment.

Cathodal Transcranial Direct Current Stimulation of the Right Wernicke's Area Improves Comprehension in Subacute Stroke Patients

Science.gov (United States)

You, Dae Sang; Kim, Dae-Yul; Chun, Min Ho; Jung, Seung Eun; Park, Sung Jong

2011-01-01

Previous studies have shown the appearance of right-sided language-related brain activity in right-handed patients after a stroke. Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) have been shown to modulate excitability in the brain. Moreover, rTMS and…

Guest Editorial: Flexible Operation and Control for Medium Voltage Direct-Current (MVDC) Grid

DEFF Research Database (Denmark)

Li, Yong; Guerrero, Josep M.; Siano, Pierluigi

2017-01-01

We appreciate very much the support from the IET Power Electronics editorial board for this Special Issue on ‘Flexible Operation and Control for Medium Voltage Direct-Current (MVDC) Grid’. In this final version for publication, 15 papers have been selected for this Special Issue. Three papers...... relate to the topology of MVDC converter, four papers relate to the control of MVDC converter, four papers relate to the introduction of application fields of MVDC grid, and four papers relate to the semiconductor power device and drives towards the application in the medium- and high-voltage DC grid....

Transcranial Direct Current Stimulation, Symptomatology, and Cognition in Psychosis: A Qualitative Review

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Tina Gupta

2018-05-01

Full Text Available Schizophrenia is a chronic, debilitating condition that affects approximately 1% of the population. Individuals diagnosed with schizophrenia typically exhibit positive (e.g., hallucinations and negative symptoms (e.g., anhedonia and impairments in cognitive function. Given the limitations of antipsychotic medication and psychotherapy in fully treating psychosis symptomatology, there has been increasing interest in other interventions such as transcranial direct current stimulation (tDCS. tDCS is a non-invasive neuromodulation technique, that is safe, cost-effective, and widely accessible. Here, we discuss treatment studies that seek to improve symptoms and cognitive performance in schizophrenia using tDCS. Currently within the literature, there is support for reductions in positive symptoms such as hallucinations after receiving tDCS. Further, studies indicate that tDCS can improve cognitive functioning, which is an area of investigation that is sorely needed, as it is unclear which types of interventions may be useful in ameliorating cognitive deficits among this group. Taken together, the evidence suggests that tDCS holds promise in improving symptoms and cognition. To that end, tDCS has critical clinical implications for this population.

Efficacy of transcranial direct current stimulation (tDCS) in reducing consumption in patients with alcohol use disorders: study protocol for a randomized controlled trial.

Science.gov (United States)

Trojak, Benoit; Soudry-Faure, Agnès; Abello, Nicolas; Carpentier, Maud; Jonval, Lysiane; Allard, Coralie; Sabsevari, Foroogh; Blaise, Emilie; Ponavoy, Eddy; Bonin, Bernard; Meille, Vincent; Chauvet-Gelinier, Jean-Christophe

2016-05-17

Approximately 15 million persons in the European Union and 10 million persons in the USA are alcohol-dependent. The global burden of disease and injury attributable to alcohol is considerable: worldwide, approximately one in 25 deaths in 2004 was caused by alcohol. At the same time, alcohol use disorders remain seriously undertreated. In this context, alternative or adjunctive therapies such as brain stimulation may play a prominent role. The early results of studies using transcranial direct current stimulation found that stimulations delivered to the dorsolateral prefrontal cortex result in a significant reduction of craving and an improvement of the decision-making processes in various additive disorders. We, therefore, hypothesize that transcranial direct current stimulation can lead to a decrease in alcohol consumption in patients suffering from alcohol use disorders. We report the protocol of a randomized, double-blind, placebo-controlled, parallel-group trial, to evaluate the efficacy of transcranial direct current stimulation on alcohol reduction in patients with an alcohol use disorder. The study will be conducted in 14 centers in France and Monaco. Altogether, 340 subjects over 18 years of age and diagnosed with an alcohol use disorder will be randomized to receive five consecutive twice-daily sessions of either active or placebo transcranial direct current stimulation. One session consists in delivering a current flow continuously (anode F4; cathode F3) twice for 13 minutes, with treatments separated by a rest interval of 20 min. Efficacy will be evaluated using the change from baseline (alcohol consumption during the 4 weeks before randomization) to 24 weeks in the total alcohol consumption and number of heavy drinking days. Secondary outcome measures will include alcohol craving, clinical and biological improvements, and the effects on mood and quality of life, as well as cognitive and safety assessments, and, for smokers, an assessment of the

Influence of direct and alternating current electric fields on efficiency promotion and leaching risk alleviation of chelator assisted phytoremediation.

Science.gov (United States)

Luo, Jie; Cai, Limei; Qi, Shihua; Wu, Jian; Sophie Gu, Xiaowen

2018-03-01

Direct and alternating current electric fields with various voltages were used to improve the decontamination efficiency of chelator assisted phytoremediation for multi-metal polluted soil. The alleviation effect of electric field on leaching risk caused by chelator application during phytoremediation process was also evaluated. Biomass yield, pollutant uptake and metal leaching retardation under alternating current (AC) and direct current (DC) electric fields were compared. The biomass yield of Eucalyptus globulus under AC fields with various voltages (2, 4 and 10 V) were 3.91, 4.16 and 3.67kg, respectively, significantly higher than the chelator treatment without electric field (2.71kg). Besides growth stimulation, AC fields increased the metal concentrations of plant tissues especially in aerial parts manifested by the raised translocation factor of different metals. Direct current electric fields with low and moderate voltages increased the biomass production of the species to 3.45 and 3.12kg, respectively, while high voltage on the contrary suppressed the growth of the plants (2.66kg). Under DC fields, metal concentrations elevated obviously with increasing voltages and the metal translocation factors were similar under all voltages. Metal extraction per plant achieved the maximum value under moderate voltage due to the greatest biomass production. DC field with high voltage (10V) decreased the volume of leachate from the chelator treatment without electric field from 1224 to 56mL, while the leachate gathered from AC field treatments raised from 512 to 670mL. DC field can retard the downward movement of metals caused by chelator application more effectively relative to AC field due to the constant water flow and electroosmosis direction. Alternating current field had more promotive effect on chelator assisted phytoremediation efficiency than DC field illustrated by more metal accumulation in the species. However, with the consideration of leaching risk, DC

Transcranial Direct Current Stimulation and behavioral models of smoking addiction

Directory of Open Access Journals (Sweden)

Paige eFraser

2012-08-01

Full Text Available While few studies have applied transcranial direct current stimulation (tDCS to smoking addiction, existing work suggests that the intervention holds promise for altering the complex system by which environmental cues interact with cravings to drive behavior. Imaging and repetitive transcranial magnetic stimulation (rTMS studies suggest that increased dorsolateral prefrontal cortex (DLPFC activation and integrity may be associated with increased resistance to smoking cues. Anodal tDCS of the DLPFC, believed to boost activation, reduces cravings in response to these cues. The finding that noninvasive stimulation modifies cue induced cravings has profound implications for understanding the processes underlying addiction and relapse. TDCS can also be applied to probe mechanisms underlying and supporting nicotine addiction, as was done in a pharmacologic study that applied nicotine, tDCS, and TMS paired associative stimulation to find that stopping nicotine after chronic use induces a reduction in plasticity, causing difficulty in breaking free from association between cues and cravings. This mini-review will place studies that apply tDCS to smokers in the context of research involving the neural substrates of nicotine addiction.

Magnetic particle imaging: current developments and future directions

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Panagiotopoulos N

2015-04-01

of different theories and technical approaches on the way to the actual implementation of the basic concept of MPI have been seen in the last few years. Research groups around the world are working on different scanner geometries, from closed bore systems to single-sided scanners, and use reconstruction methods that are either based on actual calibration measurements or on theoretical models. This review aims at giving an overview of current developments and future directions in MPI about a decade after its first appearance. Keywords: magnetic particle imaging, superparamagnetic iron oxide nanoparticles, magnetic particle spectrometer, peripheral nerve stimulation, cardiovascular interventions

Geophysical investigation of Red Devil mine using direct-current resistivity and electromagnetic induction, Red Devil, Alaska, August 2010

Science.gov (United States)

Burton, Bethany L.; Ball, Lyndsay B.

2011-01-01

Red Devil Mine, located in southwestern Alaska near the Village of Red Devil, was the state's largest producer of mercury and operated from 1933 to 1971. Throughout the lifespan of the mine, various generations of mills and retort buildings existed on both sides of Red Devil Creek, and the tailings and waste rock were deposited across the site. The mine was located on public Bureau of Land Management property, and the Bureau has begun site remediation by addressing mercury, arsenic, and antimony contamination caused by the minerals associated with the ore deposit (cinnabar, stibnite, realgar, and orpiment). In August 2010, the U.S. Geological Survey completed a geophysical survey at the site using direct-current resistivity and electromagnetic induction surface methods. Eight two-dimensional profiles and one three-dimensional grid of direct-current resistivity data as well as about 5.7 kilometers of electromagnetic induction profile data were acquired across the site. On the basis of the geophysical data and few available soil borings, there is not sufficient electrical or electromagnetic contrast to confidently distinguish between tailings, waste rock, and weathered bedrock. A water table is interpreted along the two-dimensional direct-current resistivity profiles based on correlation with monitoring well water levels and a relatively consistent decrease in resistivity typically at 2-6 meters depth. Three settling ponds used in the last few years of mine operation to capture silt and sand from a flotation ore processing technique possessed conductive values above the interpreted water level but more resistive values below the water level. The cause of the increased resistivity below the water table is unknown, but the increased resistivity may indicate that a secondary mechanism is affecting the resistivity structure under these ponds if the depth of the ponds is expected to extend below the water level. The electromagnetic induction data clearly identified the

Polarity-Specific Transcranial Direct Current Stimulation Disrupts Auditory Pitch Learning

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Reiko eMatsushita

2015-05-01

Full Text Available Transcranial direct current stimulation (tDCS is attracting increasing interest because of its potential for therapeutic use. While its effects have been investigated mainly with motor and visual tasks, less is known in the auditory domain. Past tDCS studies with auditory tasks demonstrated various behavioural outcomes, possibly due to differences in stimulation parameters or task measurements used in each study. Further research using well-validated tasks are therefore required for clarification of behavioural effects of tDCS on the auditory system. Here, we took advantage of findings from a prior functional magnetic resonance imaging study, which demonstrated that the right auditory cortex is modulated during fine-grained pitch learning of microtonal melodic patterns. Targeting the right auditory cortex with tDCS using this same task thus allowed us to test the hypothesis that this region is causally involved in pitch learning. Participants in the current study were trained for three days while we measured pitch discrimination thresholds using microtonal melodies on each day using a psychophysical staircase procedure. We administered anodal, cathodal, or sham tDCS to three groups of participants over the right auditory cortex on the second day of training during performance of the task. Both the sham and the cathodal groups showed the expected significant learning effect (decreased pitch threshold over the three days of training; in contrast we observed a blocking effect of anodal tDCS on auditory pitch learning, such that this group showed no significant change in thresholds over the three days. The results support a causal role for the right auditory cortex in pitch discrimination learning.

Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation

DEFF Research Database (Denmark)

Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus

2009-01-01

Transcranial oscillatory current stimulation has recently emerged as a noninvasive technique that can interact with ongoing endogenous rhythms of the human brain. Yet, there is still little knowledge on how time-varied exogenous currents acutely modulate cortical excitability. In ten healthy...... individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks...... at 20 min) of either anodal so-tDCS or constant tDCS (c-tDCS) to the primary motor hand area during quiet wakefulness. Simultaneously and time-locked to different phase angles of the slow oscillation, motor-evoked potentials (MEPs) as an index of corticospinal excitability were obtained...

LA EXPANSIÓN TERRITORIAL COMO FACTOR MOTIVADOR DE LA REESTRUCTURACIÓN DEL SISTEMA FINANCIERO ESPAÑOL: EL CASO DE LAS CAJAS DE AHORROS Y LAS COOPERATIVAS DE CRÉDITO / THE TERRITORIAL EXPANSION AS A MOTIVATING FACTOR OF THE RESTRUCTURING OF THE SPANISH FINANCIAL SYSTEM: THE CASE OF SAVING BANKS AND CREDIT COOPERATIVES

Directory of Open Access Journals (Sweden)

Milagros GUTIÉRREZ FERNÁNDEZ

2012-01-01

Full Text Available La actual crisis financiera internacional está actuando como catalizador de un profundo proceso de cambio en el sector bancario español que está afectando también a las entidades de crédito de la Economía Social: cajas de ahorros y cooperativas de crédito. Su modelo de banca “minorista”, centrada en la cercanía al cliente, se ha visto acompañado en los últimos años de un fuerte proceso de expansión geográfica que ha supuesto un sobredimensionamiento de su red de sucursales. Sin embargo, como consecuencia de las actuales circunstancias de la economía española en general, y del sistema bancario en particular, dicha estrategia de desarrollo interno no parece sostenible, siendo necesario que se produzca un redimensionamiento del sector, para ver recuperada la confianza en el sistema y para que éste vuelva a ser considerado como uno de los más solventes del mundo. Bajo este enfoque, el objetivo de este trabajo es analizar las distintas estrategias de expansión territorial desarrolladas por dichas entidades con el objetivo de plasmar su situación actual y comprender por qué es necesaria la reestructuración del sector. Para ello se ha empleado tanto el análisis descriptivo como el econométrico, utilizando en todo momento los datos que presentan la Confederación Española de Cajas de Ahorros (CECA y la Unión Nacional de Cooperativas de Crédito (UNACC en sus anuarios estadísticos. / The current financial international crisis is acting as catalyst of a deep process of change in the Spanish banking sector which is affecting also the credit institutions of the Social Economy: saving banks and credit cooperatives. These entities share a model of "retail" banking, centered on the nearness to the client, that has been accompanied in the last years of a strong process of geographical expansion which has supposed an oversizing of its network of branches. Nevertheless, as a consequence of the current circumstances of the Spanish

CURRENT - DIRECTION and Other Data from UNKNOWN From World-Wide Distribution from 19850101 to 19851231 (NODC Accession 8900039)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set is a backup of the 1985 tropical pacific subsurface (XBT/ MBT) thermal data. The current direction, salinity and temperature for Tropical Ocean Global...

Application possibility of the direct current conduction method for nondestructive crack measurement

International Nuclear Information System (INIS)

Riedl, R.

1982-01-01

An important value to determine the danger of cracks is the determination of crack depths. The crack depth can be determined quite accurate by means of the direct current conduction method, if one holds onto certain rules. Often complicated experimental set-ups are applied. However, portable commercial devices can be obtained that can be used for partial fluxation, that yield good results. By means of two examples: crack conduction samples in which the built-up of a constant-cracking is persued up to a certain depth, as well as the persuasion of an continuing crack in a bearing cylinder, shall be demonstrated that is very well possible to record accurate profiles with commercial devices and to avoid expensive measurement devices. (orig.) [de

Identifying therapeutic targets in gastric cancer: the current status and future direction

Science.gov (United States)

Yu, Beiqin; Xie, Jingwu

2016-01-01

Gastric cancer is the third leading cause of cancer-related death worldwide. Our basic understanding of gastric cancer biology falls behind that of many other cancer types. Current standard treatment options for gastric cancer have not changed for the last 20 years. Thus, there is an urgent need to establish novel strategies to treat this deadly cancer. Successful clinical trials with Gleevec in CML and gastrointestinal stromal tumors have set up an example for targeted therapy of cancer. In this review, we will summarize major progress in classification, therapeutic options of gastric cancer. We will also discuss molecular mechanisms for drug resistance in gastric cancer. In addition, we will attempt to propose potential future directions in gastric cancer biology and drug targets. PMID:26373844

In vitro effects of direct current electric fields on adipose-derived stromal cells.

Science.gov (United States)

Hammerick, Kyle E; Longaker, Michael T; Prinz, Fritz B

2010-06-18

Endogenous electric fields play an important role in embryogenesis, regeneration, and wound repair and previous studies have shown that many populations of cells, leukocytes, fibroblasts, epithelial cells, and endothelial cells, exhibit directed migration in response to electric fields. As regenerative therapies continue to explore ways to control mesenchymal progenitor cells to recreate desirable tissues, it is increasingly necessary to characterize the vast nature of biological responses imposed by physical phenomena. Murine adipose-derived stromal cells (mASCs) migrated toward the cathode in direct current (DC) fields of physiologic strength and show a dose dependence of migration rate to stronger fields. Electric fields also caused mASCs to orient perpendicularly to the field vector and elicited a transient increase in cytosolic calcium. Additionally, their galvanotactic response appears to share classic chemotactic signaling pathways that are involved in the migration of other cell types. Galvanotaxis is one predominant result of electric fields on mASCs and it may be exploited to engineer adult stem cell concentrations and locations within implanted grafts or toward sites of wound repair. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Transcranial Direct Current Stimulation and Power Spectral Parameters: a tDCS/EEG co-registration study

Directory of Open Access Journals (Sweden)

Anna Lisa Mangia

2014-08-01

Full Text Available Transcranial direct current stimulation (tDCS delivers low electric currents to the brain through the scalp. Constant electric currents induce shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Concomitant electroencephalography (EEG monitoring during tDCS can provide valuable information on the tDCS mechanisms of action. This study examined the effects of anodal tDCS on spontaneous cortical activity in a resting brain to disclose possible modulation of spontaneous oscillatory brain activity. EEG activity was measured in ten healthy subjects during and after a session of anodal stimulation of the postero-parietal cortex to detect the tDCS-induced alterations. Changes in the theta, alpha, beta and gamma power bands were investigated. Three main findings emerged: 1 an increase in theta band activity during the first minutes of stimulation; 2 an increase in alpha and beta power during and after stimulation; 3 a widespread activation in several brain regions.

Evidence of transcranial direct current stimulation-generated electric fields at subthalamic level in human brain in vivo.

Science.gov (United States)

Chhatbar, Pratik Y; Kautz, Steven A; Takacs, Istvan; Rowland, Nathan C; Revuelta, Gonzalo J; George, Mark S; Bikson, Marom; Feng, Wuwei

2018-03-13

Transcranial direct current stimulation (tDCS) is a promising brain modulation technique for several disease conditions. With this technique, some portion of the current penetrates through the scalp to the cortex and modulates cortical excitability, but a recent human cadaver study questions the amount. This insufficient intracerebral penetration of currents may partially explain the inconsistent and mixed results in tDCS studies to date. Experimental validation of a transcranial alternating current stimulation-generated electric field (EF) in vivo has been performed on the cortical (using electrocorticography, ECoG, electrodes), subcortical (using stereo electroencephalography, SEEG, electrodes) and deeper thalamic/subthalamic levels (using DBS electrodes). However, tDCS-generated EF measurements have never been attempted. We aimed to demonstrate that tDCS generates biologically relevant EF as deep as the subthalamic level in vivo. Patients with movement disorders who have implanted deep brain stimulation (DBS) electrodes serve as a natural experimental model for thalamic/subthalamic recordings of tDCS-generated EF. We measured voltage changes from DBS electrodes and body resistance from tDCS electrodes in three subjects while applying direct current to the scalp at 2 mA and 4 mA over two tDCS montages. Voltage changes at the level of deep nuclei changed proportionally with the level of applied current and varied with different tDCS montages. Our findings suggest that scalp-applied tDCS generates biologically relevant EF. Incorporation of these experimental results may improve finite element analysis (FEA)-based models. Copyright © 2018 Elsevier Inc. All rights reserved.

Current direction, temperature, salinity, and taxonomic code data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 1979-08-18 to 1981-01-21 (NODC Accession 8100502)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, current direction, and taxonomic data were collected using moored current meter casts in the Gulf of Mexico from August 18, 1979 to January...

Adaptive Modulation for DFIG and STATCOM With High-Voltage Direct Current Transmission.

Science.gov (United States)

Tang, Yufei; He, Haibo; Ni, Zhen; Wen, Jinyu; Huang, Tingwen

2016-08-01

This paper develops an adaptive modulation approach for power system control based on the approximate/adaptive dynamic programming method, namely, the goal representation heuristic dynamic programming (GrHDP). In particular, we focus on the fault recovery problem of a doubly fed induction generator (DFIG)-based wind farm and a static synchronous compensator (STATCOM) with high-voltage direct current (HVDC) transmission. In this design, the online GrHDP-based controller provides three adaptive supplementary control signals to the DFIG controller, STATCOM controller, and HVDC rectifier controller, respectively. The mechanism is to observe the system states and their derivatives and then provides supplementary control to the plant according to the utility function. With the GrHDP design, the controller can adaptively develop an internal goal representation signal according to the observed power system states, therefore, to achieve more effective learning and modulating. Our control approach is validated on a wind power integrated benchmark system with two areas connected by HVDC transmission lines. Compared with the classical direct HDP and proportional integral control, our GrHDP approach demonstrates the improved transient stability under system faults. Moreover, experiments under different system operating conditions with signal transmission delays are also carried out to further verify the effectiveness and robustness of the proposed approach.

Spatial and polarity precision of concentric high-definition transcranial direct current stimulation (HD-tDCS)

Science.gov (United States)

Alam, Mahtab; Truong, Dennis Q.; Khadka, Niranjan; Bikson, Marom

2016-06-01

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that applies low amplitude current via electrodes placed on the scalp. Rather than directly eliciting a neuronal response, tDCS is believed to modulate excitability—enhancing or suppressing neuronal activity in regions of the brain depending on the polarity of stimulation. The specificity of tDCS to any therapeutic application derives in part from how electrode configuration determines the brain regions that are stimulated. Conventional tDCS uses two relatively large pads (>25 cm2) whereas high-definition tDCS (HD-tDCS) uses arrays of smaller electrodes to enhance brain targeting. The 4  ×  1 concentric ring HD-tDCS (one center electrode surrounded by four returns) has been explored in application where focal targeting of cortex is desired. Here, we considered optimization of concentric ring HD-tDCS for targeting: the role of electrodes in the ring and the ring’s diameter. Finite element models predicted cortical electric field generated during tDCS. High resolution MRIs were segmented into seven tissue/material masks of varying conductivities. Computer aided design (CAD) model of electrodes, gel, and sponge pads were incorporated into the segmentation. Volume meshes were generated and the Laplace equation (\

Parameter Improved Particle Swarm Optimization Based Direct-Current Vector Control Strategy for Solar PV System

Directory of Open Access Journals (Sweden)

NAMMALVAR, P.

2018-02-01

Full Text Available This paper projects Parameter Improved Particle Swarm Optimization (PIPSO based direct current vector control technology for the integration of photovoltaic array in an AC micro-grid to enhance the system performance and stability. A photovoltaic system incorporated with AC micro-grid is taken as the pursuit of research study. The test system features two power converters namely, PV side converter which consists of DC-DC boost converter with Perturbation and Observe (P&O MPPT control to reap most extreme power from the PV array, and grid side converter which consists of Grid Side-Voltage Source Converter (GS-VSC with proposed direct current vector control strategy. The gain of the proposed controller is chosen from a set of three values obtained using apriori test and tuned through the PIPSO algorithm so that the Integral of Time multiplied Absolute Error (ITAE between the actual and the desired DC link capacitor voltage reaches a minimum and allows the system to extract maximum power from PV system, whereas the existing d-q control strategy is found to perform slowly to control the DC link voltage under varying solar insolation and load fluctuations. From simulation results, it is evident that the proposed optimal control technique provides robust control and improved efficiency.

Effects of transcranial direct current stimulation on motor learning in healthy individuals: a systematic review

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Águida Foerster

Full Text Available Introduction Transcranial direct current stimulation (tDCS has been used to modify cortical excitability and promote motor learning. Objective To systematically review published data to investigate the effects of transcranial direct current stimulation on motor learning in healthy individuals. Methods Randomized or quasi-randomized studies that evaluated the tDCS effects on motor learning were included and the risk of bias was examined by Cochrane Collaboration’s tool. The following electronic databases were used: PubMed, Scopus, Web of Science, LILACS, CINAHL with no language restriction. Results It was found 160 studies; after reading the title and abstract, 17 of those were selected, but just 4 were included. All studies involved healthy, right-handed adults. All studies assessed motor learning by the Jebsen Taylor Test or by the Serial Finger Tapping Task (SFTT. Almost all studies were randomized and all were blinding for participants. Some studies presented differences at SFTT protocol. Conclusion The result is insufficient to draw conclusions if tDCS influences the motor learning. Furthermore, there was significant heterogeneity of the stimulation parameters used. Further researches are needed to investigate the parameters that are more important for motor learning improvement and measure whether the effects are long-lasting or limited in time.

Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Kim, JunHo, E-mail: jhk@incheon.ac.kr [Department of Physics, Incheon National University, Incheon 406-772 (Korea, Republic of); National Center for Photovoltaics, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States); Kim, SeongYeon [Department of Physics, Incheon National University, Incheon 406-772 (Korea, Republic of); Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M. [National Center for Photovoltaics, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States)

2014-02-10

We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.

Edge effects in four-point direct current potential drop measurements on metal plates

International Nuclear Information System (INIS)

Lu, Y; Bowler, N; Bowler, J R; Huang, Y

2009-01-01

Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

Edge effects in four-point direct current potential drop measurements on metal plates

Science.gov (United States)

Lu, Y.; Bowler, N.; Bowler, J. R.; Huang, Y.

2009-07-01

Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

ENHANCING THE OPERATIONAL EFFICIENCY OF DIRECT CURRENT DRIVE BASED ON USE OF SUPERCONDENSER POWER STORAGE UNITS

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А. M. Mukha

2017-10-01

Full Text Available Purpose.The scientific work is intended to analyse the expansion of the load range and the implementation of regeneration braking (RB of the direct current drive by using the supercondenser power storage units. Methodology.To solve the problem, we use the methods of the electric drive theory, impulse electronics and the method of calculation of transient electromagnetic processes in linear electric circuits in the presence of super-condensers therein. Findings.The stiffness of the mechanical and electromechanical characteristics of a series motor is significantly increased, which makes it possible to use a DC drive under load, much smaller than 15…20% of the nominal one. Numerical calculations of the operation process of the supercondenser power storage unit were fulfilled with a sharp decrease in the load of a traction electric motor of a direct current electric locomotive. The possibility of RB of the direct current drive with the series motor is substantiated. The equations of the process of charging and discharging of super-condenser storage unit in RB mode are solved. The authors examined the effect of capacitance on the nature of maintaining the excitation current of an electric motor in the mode of small loads.Originality.The paper developed theoretical approaches for the transformation of soft (mechanical and electromechanical characteristics into hard ones of DC series motors. For the first time a new, combined method of the series motor RB is proposed and substantiated. Further development obtained the methods for evaluating the storage unit parameters, taking into account the criteria for reliable parallel operation of super-condensers with an electric motor field. Practical value.The proposed and substantiated transformation of soft characteristics into stiff ones allows us to use general-purpose electric drives with series motors and at low loads, and in traction electric drives - to reduce the intensity of electric stockwheel

La gestión de la calidad crediticia como alternativa de solución a los problemas de morosidad de la cartera de la micro y pequeña empresa y su efecto en los resultados económicos y financieros de la caja municipal de ahorro y crédito del santa - años 2014 y 2015.

OpenAIRE

Jiménez López, Nancy Raquel

2016-01-01

El presente trabajo de investigación ha sido realizado para entender que el problema de morosidad de la cartera de la micro y pequeña empresa genera resultados económicos financieros negativos en la Caja Municipal de Ahorro y Crédito del Santa, y que se requiere de una Gestión de Calidad para revertir esta situación para el mediano y largo plazo. Probablemente se puedan mencionar varios factores determinantes que influyen en la morosidad de las CMACS como consolidada y a la CMAC Santa en part...

Spectrochemical determination of tantalum in plutonium metal using direct current plasma emission spectrometry

International Nuclear Information System (INIS)

Fadeff, S.K.; Morris, W.F.

1983-01-01

Tantalum is determined by direct current plasma spectrometry after separation of plutonium from solution as PuF 3 . After centrifugation of the PuF 3 precipitate, a low level of plutonium remains in solution in sufficient quantity to cause spectral interferences. It is necessary to determine the plutonium by dc plasma spectrometry and apply a correction to determine low tantalum concentrations with good accuracy and precision. Tantalum can be determined down to 0.4 ppM in solution with a relative standard deviation of 10 percent. Better precision can be achieved at higher concentrations. The procedure is simple and convenient for glovebox work. 5 references, 1 figure, 1 table

Motor unit recruitment for dynamic tasks: current understanding and future directions.

Science.gov (United States)

Hodson-Tole, Emma F; Wakeling, James M

2009-01-01

Skeletal muscle contains many muscle fibres that are functionally grouped into motor units. For any motor task there are many possible combinations of motor units that could be recruited and it has been proposed that a simple rule, the 'size principle', governs the selection of motor units recruited for different contractions. Motor units can be characterised by their different contractile, energetic and fatigue properties and it is important that the selection of motor units recruited for given movements allows units with the appropriate properties to be activated. Here we review what is currently understood about motor unit recruitment patterns, and assess how different recruitment patterns are more or less appropriate for different movement tasks. During natural movements the motor unit recruitment patterns vary (not always holding to the size principle) and it is proposed that motor unit recruitment is likely related to the mechanical function of the muscles. Many factors such as mechanics, sensory feedback, and central control influence recruitment patterns and consequently an integrative approach (rather than reductionist) is required to understand how recruitment is controlled during different movement tasks. Currently, the best way to achieve this is through in vivo studies that relate recruitment to mechanics and behaviour. Various methods for determining motor unit recruitment patterns are discussed, in particular the recent wavelet-analysis approaches that have allowed motor unit recruitment to be assessed during natural movements. Directions for future studies into motor recruitment within and between functional task groups and muscle compartments are suggested.

Relationship of herpes simplex encephalitis and transcranial direct current stimulation--a case report.

Science.gov (United States)

Yang, Yuanbin; Xiao, Juan; Song, Haiqing; Wang, Ralph; Hussain, Mohammed; Song, Weiqun

2015-04-01

We report a rare case of relapsing herpes simplex encephalitis in a-37-year-old patient which was previously confirmed by positive polymerase chain reaction, herpes simplex virus (HSV) type1 IgG antibodies in cerebrospinal fluid and characterized on MRI. During the first admission, he was treated with continuous acyclovir treatment for one month with clinical improvement except for residual aphasia, for which he received a course of outpatient transcranial direct current stimulation (tDCS). A constant current of 1.2 mA was applied for 20 min twice daily. After the 4th day the patient was found to be irritable and uncooperative by staff and family members. A subsequent MRI showed significant deterioration of the lesion on comparison to the first MRI which led to discontinuation of tDCS.The relatively rapid exacerbation of HSV in only a few days is unusual. Our aim is to discuss if tDCS is related to HSV relapse and in doing so highlight possible mechanisms. Copyright © 2015. Published by Elsevier B.V.

The decolouration of methyl orange using aluminum foam, ultrasound and direct electric current

Science.gov (United States)

Liu, C. M.; Huang, X. Y.; Zhang, H. Y.; Dai, J. D.; Ning, C. C.

2018-01-01

The decolouration of methyl orange (MO) using aluminum (Al) foam, ultrasound and direct electric current (DC) is investigated. The decolouration rate (DR) of MO using only Al foam is low because there is a passivation oxide layer on the Al foam surface. Due to the low utilization of ultrasound in MO water solution medium, the DR of MO using only ultrasonic irradiation is also poor. The DR of MO is greatly increased when Al foam, ultrasonic irradiation and DC are used together. There is good synergistic effect between Al foam, ultrasound and DC in decolouration of MO. This enhancement of DR may be related to the cavitation, cleaning of Al foam surface and water electrolysis. Due to the surface charge on wire carrying stationary current, Al foam with DC acts like a serious anodes and cathodes and makes water electrolysis giving hydrogen gas to cleavage azo bond. The DC applied on Al foam is beneficial for reductive decolouration of MO. Our results show that DC is a new way for the reductive decolouration MO in water.

High-voltage direct current (HVDC) transmission - a key technology for our power supply

International Nuclear Information System (INIS)

Dorn, J.

2016-01-01

The phasing-out of nuclear power in some countries and the aspirations of reducing carbon dioxide emissions have far-reaching implications for electric power generation in Europe. In the future, renewable electricity generation will account for a considerable share of the energy mix, but this type of production is often far from the load centers. In Germany, for example, large quantities of wind energy are already generated in the north and in the North Sea, but large load centers are located several hundred kilometers south of there. This requires an expansion of the transmission network with innovative solutions. High-voltage direct-current (HVDC) transmission plays an important role, since it brings a number of advantages over conventional AC technology and makes certain requirements feasible, for example Cable transmission over longer distances. The lecture presents the advantages of HVDC, the semiconductors used as well as the basic functions and typical performance of the used converter topopologies. The plant configurations and main components are illustrated using current projects. (rössner) [de

Current direction, temperature, zooplankton, phytoplankton, and other data from moored current meter casts in the Gulf of Mexico during the Brine Disposal project, 1980-07-15 to 1981-03-20 (NODC Accession 8100610)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, temperature, salinity, and other data were collected using moored current meter casts in the Gulf of Mexico from July 15, 1980 to March 20, 1981....

Enhancing transcranial direct current stimulation via motor imagery and kinesthetic illusion: crossing internal and external tools.

Science.gov (United States)

Bodranghien, Florian; Manto, Mario; Lebon, Florent

2016-06-01

Transcranial direct current stimulation is a safe technique which is now part of the therapeutic armamentarium for the neuromodulation of motor functions and cognitive operations. It is currently considered that tDCS is an intervention that might promote functional recovery after a lesion in the central nervous system, thus reducing long-term disability and associated socio-economic burden. A recent study shows that kinesthetic illusion and motor imagery prolong the effects of tDCS on corticospinal excitability, overcoming one of the limitations of this intervention. Because changes in excitability anticipate changes in structural plasticity in the CNS, this interesting multi-modal approach might very soon find applications in neurorehabilitation.

3-D direct current resistivity anisotropic modelling by goal-oriented adaptive finite element methods

Science.gov (United States)

Ren, Zhengyong; Qiu, Lewen; Tang, Jingtian; Wu, Xiaoping; Xiao, Xiao; Zhou, Zilong

2018-01-01

Although accurate numerical solvers for 3-D direct current (DC) isotropic resistivity models are current available even for complicated models with topography, reliable numerical solvers for the anisotropic case are still an open question. This study aims to develop a novel and optimal numerical solver for accurately calculating the DC potentials for complicated models with arbitrary anisotropic conductivity structures in the Earth. First, a secondary potential boundary value problem is derived by considering the topography and the anisotropic conductivity. Then, two a posteriori error estimators with one using the gradient-recovery technique and one measuring the discontinuity of the normal component of current density are developed for the anisotropic cases. Combing the goal-oriented and non-goal-oriented mesh refinements and these two error estimators, four different solving strategies are developed for complicated DC anisotropic forward modelling problems. A synthetic anisotropic two-layer model with analytic solutions verified the accuracy of our algorithms. A half-space model with a buried anisotropic cube and a mountain-valley model are adopted to test the convergence rates of these four solving strategies. We found that the error estimator based on the discontinuity of current density shows better performance than the gradient-recovery based a posteriori error estimator for anisotropic models with conductivity contrasts. Both error estimators working together with goal-oriented concepts can offer optimal mesh density distributions and highly accurate solutions.

Transcranial Direct Current Stimulation in Tinnitus Patients: A Systemic Review and Meta-Analysis

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Jae-Jin Song

2012-01-01

Full Text Available Although transcranial direct current stimulation (tDCS has already been used to manage tinnitus patients, paucity of reports and variations in protocols preclude a comprehensive understanding. Hence, we conducted a meta-analysis based on systemic review to assess effectiveness of tDCS in tinnitus management and to compare stimulation parameters. PubMed was searched for tDCS studies in tinnitus. For randomized controlled trials (RCTs, a meta-analysis was performed. A total of 17 studies were identified and 6 of them were included in the systemic review and 2 RCTs were included in the meta-analysis. Overall 39.5% responded to active tDCS with a mean tinnitus intensity reduction of 13.5%. Additionally, left temporal area (LTA and bifrontal tDCS indicated comparable results. Active tDCS was found to be more effective than sham tDCS for tinnitus intensity reduction (Hedges' g=.77, 95% confidence interval 0.23–1.31. The efficacy of tDCS in tinnitus could not be fully confirmed by the current study because of the limited number of studies, but all studies included in the current systemic review and meta-analysis demonstrated significant tinnitus intensity improvement. Therefore, tDCS may be a promising tool for tinnitus management. Future RCTs in a large series regarding the efficacy as well as the comparison between LTA- and bifrontal tDCS are recommended.

[Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

Science.gov (United States)

Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

2015-02-01

The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

Current direction, chemical, benthic organisms, and wind wave spectra data from moored current meter casts and other instruments in the Gulf of Mexico as part of the Brine Disposal project, 1977-10-14 to 1979-08-24 (NODC Accession 7900335)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, chemical, benthic organisms, and wind direction data were collected using moored current meter casts and other instruments in the Gulf of Mexico...

Blood Stage Plasmodium falciparum Exhibits Biological Responses to Direct Current Electric Fields.

Directory of Open Access Journals (Sweden)

Lorena M Coronado

Full Text Available The development of resistance to insecticides by the vector of malaria and the increasingly faster appearance of resistance to antimalarial drugs by the parasite can dangerously hamper efforts to control and eradicate the disease. Alternative ways to treat this disease are urgently needed. Here we evaluate the in vitro effect of direct current (DC capacitive coupling electrical stimulation on the biology and viability of Plasmodium falciparum. We designed a system that exposes infected erythrocytes to different capacitively coupled electric fields in order to evaluate their effect on P. falciparum. The effect on growth of the parasite, replication of DNA, mitochondrial membrane potential and level of reactive oxygen species after exposure to electric fields demonstrate that the parasite is biologically able to respond to stimuli from DC electric fields involving calcium signaling pathways.

Electrophysiological and Behavioral Effects of Combined Transcranial Direct Current Stimulation and Alcohol Approach Bias Retraining in Hazardous Drinkers

NARCIS (Netherlands)

den Uyl, T.E.; Gladwin, T.E.; Wiers, R.W.

2016-01-01

BACKGROUND: Cognitive bias modification (CBM) can be used to retrain automatic approach tendencies for alcohol. We investigated whether changing cortical excitability with transcranial direct current stimulation (tDCS) could enhance CBM effects in hazardous drinkers. We also studied the underlying

Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharge: Part II. Model

International Nuclear Information System (INIS)

Gielen, John W A M; Groot, Simon de; Dijk, Jan van; Mullen, Joost J A M van der

2004-01-01

In a previous paper we had presented experimental results on mercury segregation due to cataphoresis in direct current operated low-pressure argon-mercury gas discharges. In this paper, we present our model to describe cataphoretic segregation in argon (or another noble gas)-mercury discharges. The model is based on the balance equations for mass and momentum and includes electrophoresis effects of electrons on mercury. Good agreement is found between the experimental results and model calculations. The model confirms our experimental observation that the mercury vapour pressure gradient depends on the local mercury vapour pressure. Furthermore, the model predicts the reversal of the direction of the transport of mercury under certain conditions (the phenomenon known as retrograde cataphoresis)

Effect of Transcranial Direct Current Stimulation in Patients With Tinnitus: A Meta-Analysis and Systematic Review.

Science.gov (United States)

Wang, Tang-Chuan; Tyler, Richard S; Chang, Ta-Yuan; Chen, Jui-Cheng; Lin, Chia-Der; Chung, Hsiung-Kwang; Tsou, Yung-An

2018-02-01

Subjective tinnitus is a phantom sensation experienced without any external source of sound that profoundly impacts the quality of life. Some investigations have claimed that transcranial direct current stimulation (tDCS) reduces tinnitus, but studies on tDCS have demonstrated variable results. This meta-analysis aimed to examine the effect of tDCS on patients with tinnitus. We searched for articles published through January 5, 2016, in Medline, Cochrane, EMBASE, and Google Scholar using the following keywords: tinnitus, transcranial direct current stimulation, and tDCS. The study outcomes were change in magnitude estimates of loudness (loudness), tinnitus-related distress (distress), and Tinnitus Handicap Inventory (THI). Pooled results demonstrated that tDCS did not have a beneficial effect on loudness (pooled standardized difference in means = 0.674, 95% CI, -0.089 to 1.437, P = .083). Further, the pooled results demonstrated a greater reduction in distress for the tDCS group (pooled standardized difference in means = 0.634, 95% CI, 0.021-1.247, P = .043). We conclude that the pooled results demonstrated a greater reduction in distress for groups treated with tDCS as compared with those administered a sham treatment.