Simulation of an absorption based solar cooling facility using a geothermal sink for heat rejection

An important issue of solar cooling facilities based on absorption cycles and sometimes not given the necessary attention is the recooling process of the absorber and condenser. This is critical in the overall behaviour of the facility because the condensation and absorption temperatures will affect the COP and cooling capacity of the chiller. Most of the time the recooling process is made by using a wet cooling tower in a closed loop through the absorber and condenser. The use of a wet cooling tower gives good results in terms of cooling capacity and COP, but presents some health risk, like legionella, and its use is restricted to the industrial sector and places where water scarcity is not present. This paper presents the modification of the already validated TRNSYS simulation of a solar cooling facility, implementing a geothermal heat sink instead of the wet cooling tower in order to dissipate the heat generated internally in the absorption chiller. Simulation results shows that a geothermal heat sink composed of 6 boreholes of 100 meters of depth should be sufficient in order to substitute the wet cooling tower, for a typical Spanish single family dwelling.Universidad Carlos III de Madrid - ITEA Research GroupPublicad

Efecto del Nitrógeno, Fósforo, Potasio y sus Interacciones en la producción de Coliflor (Brassica oleracea var. botrytis) Rn Costa Rica

En Costa Rica la coliflor (Brassica oleracea var. botrytis) se ha sembrado tradicionalmente en las faldas del Volcán Irazú. Según el IFAM (7), en 1972 se sembraron 180 hectáreas para el consumo local en fresco y un pequeño porcentaje para la industria de encurtidos.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Estación Experimental Agrícola Fabio Baudrit Moreno (EEAFBM

Mejora de la productividad del almac?n en una empresa comercializadora mediante la implementaci?n de la gesti?n de inventarios

El presente estudio tiene como objetivo principal determinar la influencia de la Gesti?n de Inventarios en la mejora de la productividad del almac?n de la empresa comercializadora WANCORE S.A. y objetivos espec?ficos; establecer la contribuci?n de la rotaci?n de inventarios y la valorizaci?n de los inventarios en la entrega de pedidos sin errores. As? mismo, el ?ltimo objetivo espec?fico buscar determinar la influencia de la exactitud de inventarios sobre el cumplimiento a tiempo de los despachos. La investigaci?n es de tipo aplicada correlacional, con un dise?o cuasi-experimental. La aplicaci?n de las herramientas de la Gesti?n de Inventarios logr? solucionar el inconveniente de la baja productividad; porque la empresa empez? a reportar altos ?ndices de devoluci?n de pedidos, p?rdidas de mercader?a, despachos atendidos fuera de tiempo, errores en la preparaci?n de pedidos, entre otros motivos. Por ello, con la intervenci?n de la gesti?n de inventarios, la productividad del almac?n logr? mejorar; ya que se obtuvo un incremento del 20%. Finalmente, la conclusi?n principal es la determinaci?n de la contribuci?n total del sistema en la mejora de la productividad

A hydrogen beam to characterize the ASACUSA antihydrogen hyperfine spectrometer

The antihydrogen programme of the ASACUSA collaboration at the antiproton decelerator of CERN focuses on Rabi-type measurements of the ground-state hyperfine splitting of antihydrogen for a test of the combined Charge-Parity-Time symmetry. The spectroscopy apparatus consists of a microwave cavity to drive hyperfine transitions and a superconducting sextupole magnet for quantum state analysis via Stern-Gerlach separation. However, the small production rates of antihydrogen forestall comprehensive performance studies on the spectroscopy apparatus. For this purpose a hydrogen source and detector have been developed which in conjunction with ASACUSA's hyperfine spectroscopy equipment form a complete Rabi experiment. We report on the formation of a cooled, polarized, and time modulated beam of atomic hydrogen and its detection using a quadrupole mass spectrometer and a lock-in amplification scheme. In addition key features of ASACUSA's hyperfine spectroscopy apparatus are discussed.

\u3cem\u3eRickettsia felis\u3c/em\u3e in \u3cem\u3eCtenocephalides felis\u3c/em\u3e from Guatemala and Costa Rica

Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal2 in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis