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  • Engineering (General)  (2)
  • Sea level  (2)
  • Thermohaline circulation  (2)
  • 2005-2009  (6)
  • 1955-1959
  • 1
    Publication Date: 2019-07-19
    Description: Two helium refrigerators, each rated for 3.5KW at 20K, are used at NASA s Johnson Space Center (JSC) in Building No. 32 to provide cryo-pumping within two large thermal-vacuum chambers. These refrigerators were originally commissioned in 1996. Equipment refurbishment and upgrades to the controls of these refrigerators were recently completed. This paper describes some of the mechanical and control issues that necessitated the equipment refurbishment and controls change-over. It will describe the modifications and the new process control which allows the refrigerators to take advantage of the Ganni Cycle "floating pressure" control technology. The upgrades -- the controls philosophy change-over to the floating pressure control technology and the newly refurbished equipment -- have greatly improved the performance, stability, and efficiency of these two refrigerators. The upgrades have also given the operators more information and details about the operational status of the main components (compressors, expanders etc.) of the refrigerators at all operating conditions (i.e.: at various loads in the vacuum chambers). Capabilities, configuration, and performance data pre, and post, upgrading will be presented.
    Keywords: Engineering (General)
    Type: 25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection; 8; NASA/CP-2008-214164
    Format: text
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  • 2
    Publication Date: 2019-07-19
    Description: NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.
    Keywords: Engineering (General)
    Type: 25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection; 9; NASA/CP-2008-214164
    Format: text
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  • 3
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    Instituto Oceanográfico de la Armada, Guayaquil, Ecuador
    Publication Date: 2021-05-19
    Description: Usando series de tiempo de promedios diarios de nivel del mar en años caracterizados por la ocurrencia de eventos El Niño en la estación mareográfica de La Libertad (02°15'S-81°27'W), se aplicaron las técnicas del análisis espectral para determinar la correlación existente entre los eventos pasados y el primer semestre de 1997. Se obtuvieron niveles significativos de coherencia entre el evento El Niño 1982-1983 con el evento del 1997. El análisis espectral comparativo permitió obtener las ondas predominantes, la amplitud y el ángulo de fase de cada una de ellas. Con estos parámetros y aplicando la serie de Fourier, se generó una serie del nivel del mar que permitió predecir el comportamiento del nivel del mar en La Libertas desde julio 97 hasta marzo 98 con un 73% de correlación. El método fue óptimo para indicar con buena aproximación el comportamiento dinámico del evento cálido aún cuando los valores absolutos de nivel del mar tuvieron un margen mayor de error. Se evidenció la estrecha relación entre el comportamiento dinámico y térmico del océano durante el desarrollo de un evento El Niño. El análisis de los espectros evidenció el importante aporte de energía de las ondas interestacionales en el océano y sugiere que los eventos El Niño tienen patrones de interacción de las ondas océanicas que podrían ser de naturaleza recurrente y por lo tanto predecibles a partir de datos históricos disponibles.
    Description: Using times series of daily averages of sea level during years of occurrence of events El Niño in the station of La Libertad (02°15'S-81°27'W), techniques of spectral analysis were applied to determine the existence correlation between the last events and the first semester of 1997. Significant levels of coherence were obtained among the event El Niño 1982-1983 with the event of 1997. The comparative spectral analysis allowed to obtain the predominant waves, the amplitude and the angle of phase of each one of them. With this parameters and applying the Fourier series, a sea level serie was generated and allowed to predict the behavior of the sea level in La Libertad since july 1997 until march 1998 with a correlation of 73%. The method was acceptable to indicate with a close approach the dynamic behavior of the warm event when the absolute values of sea level had a bigger margin of error. The narrow relationship was evidenced among the dynamic and thermal behavior of the ocean during the development of an event El Niño. The analysis of the spectra evidenced the important contribution of energy of the intraseasonal waves in the ocean. It suggest that the events El Niño have interaction patterns of the oceanic waves that would be recurred and there fore predictable.
    Description: Incluye ref.bibl., grafs., tbls.
    Description: Published
    Keywords: Prediction ; Spectral analysis ; Sea level ; Prediction ; El Nino phenomena ; Spectral analysis ; Fourier analysis ; Sea level ; Oceanographic data ; Time series
    Repository Name: AquaDocs
    Type: Journal Contribution , Non-Refereed , Article
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  • 4
    Publication Date: 2021-05-19
    Description: El presente trabajo permite conocer el comportamiento de la cuña salina en el sistema Río Guayas - Canal de Jambelí, conociendo que el Río Guayas abastece de agua a Guayaquil, puerto principal del país, y a muchas otras poblaciones.
    Description: The present work allows to establish the behavior of the salinity of the water, time of renovation and its effect on the quality of water in two established stages: increase in the level of the sea in 0.3 m. and 1.0 m. In the System of the Guayas Channel in Jambelí, considering the exchange of waters that exists between the Guayas River and the sea. The horizontal and vertical gradients of salinity are intimately bound with the flow of the Guayas River, as long as the flow increases the intrusion of the saline wedge will be minor. During the dry station the vertical gradients of salinity are maximums in the sector between The Esclusas - Point Stone. It is in this area where they give up the processes of mixture in a higher form. The gradient mentioned changes, being found in the south during the humid season. The gradients of salinity are important in the area already mentioned, after this, the variations don't present too many changes, this is a reason why it can be ignore. The advance of the saline wedge will be harmful, in the cases, where the water is used directly due to that an excess of salted water that will cause damages in the agriculture production of corn, rice, banana tree, etc. as well as the populations settled in the bordes of the Daule and Babahoyo rivers who use the water directly from the river for their daily work.
    Description: Incluye ref.bibl., grafs., tbls.
    Description: Published
    Keywords: Water quality ; Irrigation water ; Rivers ; Sea level ; Water quality ; Sea level ; Climatic changes ; Salt-wedge estuaries ; Salt wedges ; Salinity gradients ; Irrigation water ; River water ; Rivers
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 5
    Publication Date: 2021-05-19
    Description: El objetivo del presente trabajo es estudiar la estructura termohalina superficial y subsuperficial de una región del Pacífico Sudeste (Guayaquil-Valparaíso), Fig. 1, durante el término de la primavera austral de 1997 para determinar los posibles cambios en la circulación. Para esta fecha se dio comienzo la VII Expedición Ecuatoriana a la Antártida a bordo del B/I ORION y simultáneamente se estaba desarrollando un evento ENOS de intensidad fuerte.
    Description: During the VII Ecuadorian Expedition to the Antarctic (December of 1997) the B/I ORION carried out oceanographic stations and XBT launches in the track (Guayaquil-Valparaiso in order to determine the change in circulation and termohaline structure on Southeast Pacific during the development of the ENSO event. By means of Sea Surface Temperature, sections of temperature and salinity diagrams T/S, were observed, positive surface and subsurface anomalies of subtropical surfaces waters that suggest a reforcement of the Equatorial undercurrent those feed the Gunther Undercurrent and the Perú-Chile Countercurrent those go toward the south, forcing to turn early toward the west to the Oceanic Current of Humboldt and to fathom the Chile Coastal Current Measures of direct current even the 100 meters demonstrate the great flow from north.
    Description: Incluye ref.bibl., ilus.
    Description: Published
    Description: Pacifico sudeste
    Keywords: El Nino phenomena ; Thermohaline circulation ; Surface temperature ; T/S diagrams ; Current direction ; Countercurrents ; Current measurement ; Ocean circulation
    Repository Name: AquaDocs
    Type: Journal Contribution , Non-Refereed , Article
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  • 6
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    Instituto Oceanográfico de la Armada, Guayaquil, Ecuador
    Publication Date: 2021-05-19
    Description: El objetivo de este artículo es documentar científicamente la evolución del evento "El Niño" en Ecuador, desde el punto de vista oceanográfico, sugiriendo posibles mecanismos involucrados en este proceso, vinculados a ondas interestacionales Kelvin en el océano (Kessler et al., 1995) que actúan como contraparte a las oscilaciones de 60 a 75 días en la atmósfera (Maden - Julian, 1995) y más específicamente de ondas encontradas en los espectros de nivel medio del mar y TSM en el mar ecuatoriano- colombiano con estas mismas características (Martínez, 1998).
    Description: Incluye ref.bibl., grafs.
    Description: Published
    Keywords: Air temperature ; Variability ; Isotherms ; Thermohaline circulation ; El Nino phenomena ; Surface temperature ; Cruises ; Kelvin waves ; Air temperature ; Mean sea level ; Salinity charts
    Repository Name: AquaDocs
    Type: Journal Contribution , Non-Refereed , Article
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