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Sample records for al norte del

  1. Educational and Demographic Profile: Del Norte County.

    ERIC Educational Resources Information Center

    California Postsecondary Education Commission, 2004

    2004-01-01

    This profile uniquely presents a variety of educational and socioeconomic information for Del Norte County, nearby counties, and the state. The profile highlights the relationship between various factors that affect the economic well-being of individuals and communities. This presentation of information provides a framework for enhanced…

  2. Del Norte means north to recycling

    SciTech Connect

    Aquino, J.T.

    1998-06-01

    Del Norte Regional Recycling and Transfer Station is owned by the city of Oxnard, California and operated by BLT Enterprises, Inc. The Del Norte facility--located in southwestern Ventura County about an hour northwest of Los Angeles--processes polyethylene terephthalate (PET) and high-density polyethylene (HDPE) plastic containers, aluminum, steel, glass, old corrugated containers (OCC), newspapers, computer printout paper, white and colored ledger paper, coated book, supermix paper, telephone books, and old magazines. According to the company, there has been virtually no community opposition to the site. The facility has few neighbors, and those are agricultural. To keep the community relationship strong, the facility`s design and location all but eliminated odor and noise complaints. The building was designed against the prevailing wind pattern, and BLT processes odorous material fast. A misting system installed for dust suppression also can be used with a solution for odor control should the need arise.

  3. 75 FR 11104 - Del Norte Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-10

    ... Forest Service Del Norte Resource Advisory Committee (RAC) AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Del Norte Resource Advisory Committee (RAC) will meet in Crescent City... and Designated Federal Official roles and (5) review operational guidelines; (6) selection of...

  4. 88. Paso Del Norte Hotel, 115117 South El Paso St., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    88. Paso Del Norte Hotel, 115-117 South El Paso St., south facade, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  5. 91. Paso Del Norte Hotel, 115117 South El Paso St., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    91. Paso Del Norte Hotel, 115-117 South El Paso St., east facade, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  6. PASO DEL NORTE HOTEL, 115117 S. EL PASO ST., SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PASO DEL NORTE HOTEL, 115-117 S. EL PASO ST., SOUTH AND EAST FACADES, WEST SIDE OF STREET - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  7. 92. Paso Del Norte Hotel, 115117 South El Paso St., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    92. Paso Del Norte Hotel, 115-117 South El Paso St., interior, lobby rotunda - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  8. PASO DEL NORTE HOTEL, 115117 S. EL PASO ST., EAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PASO DEL NORTE HOTEL, 115-117 S. EL PASO ST., EAST FACADE, WEST SIDE OF STREET - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  9. 65. Photographer unknown March 1931 DEL NORTE COUNTY, SECTION B, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    65. Photographer unknown March 1931 DEL NORTE COUNTY, SECTION B, HIGHWAY 1, 1-DN-1-B #66A, STA. 166.0+00 WIDENED ROADBED BEFORE COVERING LOG CRIB, 3-31. BACK READS: WIDENING ROAD BED WITH LOGS, APPROX 30 SQUARE & 60 LONG ON DN-1 SEC B STA 156+. Stamped office copy, - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  10. 77 FR 50080 - Del Norte County Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ...The Del Norte County Resource Advisory Committee (RAC) will meet in Crescent City, California. The committee is authorized under the Secure Rural Schools and Community Self-Determination Act (Pub. L. 112-141) (the Act) and operates in compliance with the Federal Advisory Committee Act. The purpose of the committee is to improve collaborative relationships and to provide advice and......

  11. 87. Paso Del Norte Hotel, 115117 South El Paso St., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    87. Paso Del Norte Hotel, 115-117 South El Paso St., south and east facades, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  12. 89. Paso Del Norte Hotel, 115117 South El Paso St., ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    89. Paso Del Norte Hotel, 115-117 South El Paso St., detail view of roof, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  13. Modeling Visibility in the EL Paso del Norte Region

    NASA Astrophysics Data System (ADS)

    Fitzgerald, R. M.; Medina, R.; DuBois, D. W.; Novlan, D.

    2013-12-01

    Poor visibility is a subject of growing public concern throughout the U.S, and an active area of research. Its societal impacts in air quality, aviation transport and traffic are significant. Aerosols play a fundamental role in the attenuation of solar radiation, and also affect visibility. The scattering and extinction coefficients of aerosol particles in the Paso del Norte Region have been calculated using the T- matrix model in conjunction with a laser particle counter. Inter-comparison of the model's results of the scattering and absorption coefficients against the corresponding data from a Photoacustic Extinctiometer instrument (which measures in-situ absorption and scattering coefficients of aerosol particles) shows excellent agreement. In addition, the volume-weighted method is used to determine the composite index of refraction which is representative of the aerosols for the Paso del Norte Airshed to obtain information of the type of aerosol particles present in the Airshed. The Single Scattering Albedo has also been retrieved using our methodology to obtain further insight into the type of aerosols present on a given day. Finally, the Koschmieder equation has been used to calculate the visual range or visibility, and was correlated with the PM2.5 and PM10 particle concentration present in the Airshed. Our methodology will allow a better understanding of the size and type of aerosol particles that are most detrimental to the visibility for the Paso del Norte Region.

  14. Modeling visibility in the Paso del Norte (PDN) Region

    NASA Astrophysics Data System (ADS)

    Medina Calderon, Richard

    Poor visibility is a subject of growing public concern throughout the U.S, and an active area of research. Its societal impacts on air quality, aviation transport and traffic are significant. Aerosols play a fundamental role in the attenuation of solar radiation, and also affect visibility. The scattering and extinction coefficients of aerosol particles in the Paso del Norte Region have been calculated using the T- matrix model in conjunction with a laser particle counter. Inter-comparison of the model's results of the scattering and absorption coefficients against the corresponding data from a Photoacustic extinctiometer instrument (which measures in-situ absorption and scattering coefficients of aerosol particles) shows excellent agreement. In addition, the volume-weighted method is used to determine the composite index of refraction which is representative of the aerosols for the Paso del Norte Region to obtain information of the type of aerosol particles present in the Region. The Single Scattering Albedo has also been retrieved using this methodology to obtain further insight into the type of aerosols present on a given day. Finally, the Koschmieder equation has been used to calculate the visual range or visibility, and was correlated with the PM2.5 and PM10 particle concentration present in the Region. Our methodology will allow a better understanding of the size and type of aerosol particles that are most detrimental to the visibility for the Paso Del Norte Region.

  15. 62. R.L.T., photographer November 1, 1934 DEL NORTE COUNTY, SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. R.L.T., photographer November 1, 1934 DEL NORTE COUNTY, SECTION D, HIGHWAY 1. REDWOOD CLEARING ON EXISTING LINE, 1-DN-71-A #26, R.L.T. 11-1-34. Stamped office copy. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  16. 63. G.F.H., photographer July 30, 1932 DEL NORTE COUNTY, SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    63. G.F.H., photographer July 30, 1932 DEL NORTE COUNTY, SECTION A, HIGHWAY 1. 1-DN A #124, STA. 164=00 SHOWING DRAINAGE CONDITIONS, G.F.H., 7-30-32. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  17. 66. Photographer unknown March 1920'S DEL NORTE COUNTY, SECTION B, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. Photographer unknown March 1920'S DEL NORTE COUNTY, SECTION B, HIGHWAY 1. 1-DN 1-B #9, CORDUROY DETOUR INTO CRESCENT CITY, 2-2 (3?). Stamped office copy. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  18. Ozone studies in the Paso del Norte region

    NASA Astrophysics Data System (ADS)

    Becerra-Davila, Fernando

    The Paso del Norte region forms the largest contiguous bi-national conglomerate on the US-Mexico border. With a combined population of around 2 million inhabitants, the Paso del Norte region is isolated, more than 500 km away from the nearest urban area of comparable size, thus making it an ideal location for air quality studies of an isolated urban environment. The meteorological conditions leading to a high ozone episode in this region, such as the historical ozone episode of June 2006, are analyzed. It is well known that stagnation and minimal winds, high temperatures, and pressure ridges over the region are conducive to high ozone episodes. In addition, the planetary boundary height is studied to understand its impact on high ozone episodes. Several studies report that ground level ozone non-attainment regulations could be caused not only by local emissions, but also by atmospheric transport. In this work the atmospheric advection of pollutants into the region is analyzed using HYSPLIT backward trajectories. Furthermore, a novel backward trajectory clustering technique is implemented for the summer of 2006. The "ozone weekend effect" (OWE) is a phenomenon by which in some geographical regions ambient ozone concentrations tend to be higher on weekends than on weekdays, despite the lower emissions of ozone precursors during those days. The observed local OWE has never previously been studied in terms of the photolysis rates of four of the main ozone precursors. In this research a novel method that allows the calculation of actinic fluxes, photolysis frequencies and photolysis rates with a high degree of accuracy and reliability has been developed. This method utilizes a combination of the experimental data available for this region in conjunction with a radiative transfer model (TUV model). Three weekend-weekday cases during summers 2006, 2009 and 2010 are studied in this work. In this research, the photolysis impact on the local OWE is studied. The results

  19. Clean cities: Award winning coalition -- Paso del Norte

    SciTech Connect

    O'Connor, K.

    1999-10-25

    Designated the 41st Clean Cities coalition in November 1995, the Paso del Norte Clean Cities Coalition (PDNCCC) is the first in the country to gain international participation. Spanning the US-Mexico border; the coalition includes stakeholders from El Paso, Texas; Ciudad Juarez, Mexico; and Las Cruces, New Mexico. PDNCCC developed a comprehensive plan to jump-start its program place, alternative fuel vehicles (AFVs) on the road, and eliminate barriers inhibiting alternative fuel market growth. PDNCC raised more than $2.3 million for alternative fuel activities and clean air initiatives in less than 26 months. In 1998, the US Department of Energy (DOE) recognized that PDNCCC accomplishment with its Rainmaker Award for leveraging the most funds from outside sources. PDNCCC is proud of its efforts to drive the alternative fuels and AFV market in the El Paso/Juarez region.

  20. 90. Paso Del Norte Hotel, 115117 South El Paso St.,east ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    90. Paso Del Norte Hotel, 115-117 South El Paso St.,east facade, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

  1. Paso del Norte ozone study VOC measurements, 1996

    SciTech Connect

    Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

    1999-11-01

    The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

  2. Paso del Norte ozone study VOC measurements, 1996

    SciTech Connect

    Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

    1999-01-01

    The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

  3. 1996 Paso del Norte ozone study VOC measurements

    SciTech Connect

    Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.; Ramadan, A.B.

    1999-07-01

    Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US and Mexican side of the border during a six week period of the 1996 Paso del Norte Ozone Study. On nine intensive operations (IOP) days, when high ozone concentrations were forecast, five 2-hr samples were collected at five IOP sites, three on the US side and two on the Mexican side. Six special survey sites on the US side and two on the Mexican side were sampled to characterize up-wind, down-wind and other emissions. In Ciudad Juarez, rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane and butane fuels, and an industrial manufacturing site were sampled. Carbonyl samples were collected at three surface sites. Carbonyl and canister grab samples were also collected during aircraft and hot air balloon flights. Most of the hydrocarbon samples were collected in electro-polished stainless steel canisters which were returned to laboratories for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration GC-FID. The carbonyl samples were collected on DNPH impregnated C-18 Sep-Pak cartridges and analyzed by HPLC to quantify 13, C-1 to C-8 species. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning at three vehicle-dominated sites, two in Ciudad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Ciudad Juarez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde and acetone.

  4. DELIVERING TIMELY AIR QUALITY, TRAFFIC, AND WEATHER INFORMATION TO YOUR COMMUNITY/THE PASO DEL NORTE ENVIRONMENTAL MONITORING PROJECT

    EPA Science Inventory

    EPA has developed a technology transfer handbook for the EMPACT Paso del Norte Project. The EMPACT Paso del Norte Environmental Monitoring Project is a mobile vehicle emissions project that involves the international community of El Paso, TX; Sundland Park, NM; and Juarez, Mexico...

  5. ATMOSPHERIC VOLATILE ORGANIC COMPOUND MEASUREMENTS DURING THE 1996 PASO DEL NORTE OZONE STUDY

    EPA Science Inventory

    Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juarez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five...

  6. Urban Impact of Dissolved Metals in the Paso del Norte Segment of the Rio Grande

    ERIC Educational Resources Information Center

    Freiwan, Sumayeh Ahmad

    2013-01-01

    The Paso del Norte segment of the Rio Grande experiences two seasons per year; the (wet) irrigation season and the (dry) non-irrigation season. The goal of this study was to improve the understanding of occurrence and contribution of dissolved metals in this region during the non-irrigation season. The objectives of this study were to (1) evaluate…

  7. Phenomena that influence high ozone concentrations in the Paso del Norte area

    SciTech Connect

    MacDonald, C.P.; Roberts, P.T.; Main, H.H.; Dye, T.S.; Yarbrough, J.

    1998-12-31

    This paper summarizes the results of analyses of meteorological and air quality data for the 1996 Paso del Norte Ozone Study. The purpose of these data analyses was to develop an understanding of the significant chemical and physical processes which lead to high concentrations of ozone in the Paso del Norte study region which includes El Paso, TX; Sunland Park, NM; and Juarez, Mexico. This analysis has shown that the high ozone concentrations are a result of slow convective boundary layer growth, reduced convective boundary layer depth, light surface winds, and high morning surface ozone precursor concentrations. Overlying meteorological conditions observed during high ozone episodes include an upstream aloft high pressure system, aloft warming, and weak surface pressure gradients. The analysis has also shown that aloft carryover of ozone and ozone precursors does not significantly contribute to the surface ozone concentration. Furthermore, hydrocarbon and NO{sub x} data, although spatially limited, show that the system is most often NO{sub x} rather than VOC limited.

  8. Light scattering from aerosol particles in the El Paso del Norte region / the effect of humidity

    NASA Astrophysics Data System (ADS)

    Medina Calderon, Richard

    Atmospheric aerosols play an important role in climate forcing, through scattering and absorption of the incoming solar radiation. The extinction of light by the presence of atmospheric aerosols was studied using two first-principle models, and corresponding computer codes. In the first model the extinction of light from irregularly shaped aerosol particles was analyzed. In the second model it was assumed that the irregularly shaped aerosol particles were covered by a film of water, and the hygroscopicity and the extinction of light by the aerosols was analyzed. These models were then applied to the Paso del Norte region and their light extinction results compared with a local extinctiometer. The inter-comparison of the models extinction results and the extinctiometer values were well correlated. It was observed that for high humidity days the model that used an aerosol particle covered with a water film correlated better with the experimental extinctiometer measurements. While these two models were validated in the Paso del Norte region, they are also applicable to any other region, under humid or dry atmospheric conditions.

  9. Paso del Norte pilot border study of ozone precursors and air toxics

    SciTech Connect

    Zielinska, B.; Sheetz, L.; Harshfield, G.

    1996-12-31

    A comprehensive monitoring program for ozone precursors and air toxics in the Paso del Norte border area is planned by the U.S. EPA for the Summer of 1996. A pilot study was carried out in October 1995 in the Paso del Norte area (El Paso, Texas, Ciudad Juarez, Chihuahua, and Sunland Park, New Mexico) to test the appropriateness of proposed sampling and analysis methods and to provide preliminary data to be used for planning the Summer 1996 study. Two monitoring sites were selected, one in Ciudad Juarez, and one in the El Paso area. Samples were collected every second day from October 21 to October 31, from 0300 to 0900 hr using stainless steel canisters (for VOC in the C{sub 2}-C{sub 12} range), Tenax-TA solid adsorbent cartridges (for C{sub 8}-C{sub 20} hydrocarbons). DNPH impregnated C{sub 18} Sep-Pack cartridges (for carbonyl compounds) and Teflon impregnated glass fiber filters followed by PUF/YAD/PUF {open_quotes}sandwich{close_quotes} cartridges (for SVOC). This paper discusses the data set obtained from the analyses of these samples. 6 refs., 7 figs.

  10. Attic dust analysis approach for evaluation of heavy metal deposition in the El Paso Del Norte Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the 90 years from 1887 to 1977, a large smelter in the El Paso Del Norte region of North America smelted many ores including copper, lead, and zinc. In order to identify the patterns of heavy metal dispersion from the smelter, we sampled attic dust and dust from undisturbed surfaces in 15 bu...

  11. Application of GIS and remote sensing methods to the paleohydrography of the Paso del Norte region

    NASA Astrophysics Data System (ADS)

    Kennedy, John F.

    The purpose of this project is to use geographic information system (GIS) and remote sensing methods to investigate the paleohydrology of the Paso del Norte region during the latest pluvial event. During the research I gathered the best available geologic and hydrographic data sets and integrated these data within a GIS in order to create a digital paleohydrologic database for the region. In particular, I used the GIS to reconstruct the hydrography (i.e. streams, lakes, and watershed boundaries) that existed as a results of increased precipitation and a decrease in temperature in the recent geologic past. The existence of the pluvial lakes had an impact on ground-water and surface-water flow systems in this region. The results of my research are presented as two papers ready for peer-review publication submission and a third paper that is a previously published work. (1) Using GIS and Remote Sensing to Reconstruct Late Quaternary and Early Holocene Paleo-Hydrography Using Climate Data and Modern Topography---an Example from the Southwestern US. This paper describes the methods used to create a paleo-hydrography system for the Paso del Norte region, and the development of a water-balance equation that estimates the inputs and outputs of this system. (2) Estimating Water-Balance Equation for Playas in the Tularosa Basin of Southern New Mexico. This paper describes the calibration and testing of the GIS model presented in the first paper. Before it can be applied to paleohydrologic systems, it must be shown to reasonably approximate playa systems in the region under current conditions. Water balances were calculated for several playas and their associated drainages. (3) The Hydrogeologic Framework of Basin-Fill Aquifers and Associated Ground-water flow Systems in Southwestern New Mexico---An Overview. The paper is an overview of work done by many hydrogeologists in the Paso del Norte region; however, the primary source of most of our current knowledge is based on the

  12. Geology and depositional environments of the Guadalupian rocks of the northern Del Norte Mountains, West Texas

    USGS Publications Warehouse

    Rudine, S.F.; Wardlaw, B.R.; Rohr, D.M.; Grant, R.E.

    2000-01-01

    The Guadalupian rocks of the northern Del Norte Mountains were deposited in a foreland basin between land of the Marathon orogen and a carbonate shoal established on the geanticline separating the foreland basin from the Delaware basin. Deposition was alternately influenced by coarse clastic input from the orogen and carbonate shoal, which interrupted shallow basinal siltstone depletion. Relatively deeper-water deposition is characterized by carbonate input from the shoal, and relatively shallow-water deposition is characterized by sandstone input from the orogen. Deposition was in five general transgressive-regressive packages that include (1) the Road Canyon Formation and the first siltstone member and first sandstone member of the Word Formation, (2) the second siltstone member, Appel Ranch Member, and limy sandy siltstone member of the Word Formation, (3) the Vidrio Formation, (4) the lower and part of the middle members of the Altuda Formation, and (5) part of the middle and upper members of the Altuda Formation.

  13. Vigilando la Calidad del Agua de los Grandes Rios de la Nacion: El Programa NASQAN del Rio Grande (Rio Bravo del Norte)

    USGS Publications Warehouse

    Lurry, Dee L.; Reutter, David C.; Wells, Frank C.; Rivera, M.C., (translator); Munoz, A.

    1998-01-01

    La Oficina del Estudio Geologico de los Estados Unidos (U.S. Geological Survey, 0 USGS) ha monitoreado la calidad del agua de la cuenca del Rio Grande (Rio Bravo del Norte) desde 1995 como parte de la rediseiiada Red Nacional para Contabilizar la Calidad del Agua de los Rios (National Stream Quality Accounting Network, o NASOAN) (Hooper and others, 1997). EI programa NASOAN fue diseiiado para caracterizar las concentraciones y el transporte de sedimento y constituyentes quimicos seleccionados, encontrados en los grandes rios de los Estados Unidos - incluyendo el Misisipi, el Colorado y el Columbia, ademas del Rio Grande. En estas cuatro cuencas, el USGS opera actualmente (1998) una red de 40 puntos de muestreo pertenecientes a NASOAN, con un enfasis en cuantificar el flujo en masa (la cantidad de material que pasa por la estacion, expresado en toneladas por dial para cada constituyente. Aplicacando un enfoque consistente, basado en la cuantificacion de flujos en la cuenca del Rio Grande, el programa NASOAN esta generando la informacion necesaria para identificar fuentes regionales de diversos contaminantes, incluyendo sustancias qui micas agricolas y trazas elementos en la cuenca. EI efecto de las grandes reservas en el Rio Grande se puede observar segun los flujos de constituyentes discurren a 10 largo del rio. EI analisis de los flujos de constituyentes a escala de la cuenca proveera los medios para evaluar la influencia de la actividad humana sobre las condiciones de calidad del agua del Rio Grande.

  14. The Influence of Photolysis Rate Constants in Ozone Production for the Paso del Norte Region

    NASA Astrophysics Data System (ADS)

    Becerra, Fernando; Fitzgerald, Rosa

    2012-03-01

    In this research work we are focusing on understanding the relationship between photolysis rates and the photochemical ozone changes observed in the Paso del Norte region. The city of El Paso, Texas together with Ciudad Juarez, Mexico, forms the largest contiguous bi-national metropolitan area. This region suffers year-round ozone pollution events, and a better understanding is needed to mitigate them. Previous studies have found that ambient ozone concentrations tend to be higher on weekends rather than on weekdays, this phenomenon being referred to, as the ``weekend effect.'' If the ozone standard is exceeded more frequently on weekends, then this phenomenon must be considered in the design of ozone control strategies. In this work we investigate some of the most representative weekend ozone episodes at El Paso, TX, during the years 2009, 2010 and 2011 using the ozone photolysis rates. In this research the TUV radiative-transfer model is used to calculate the local photolysis rates and a UV MFRSR instrument is used to obtain experimental parameters. Seasonal variations and the weekday-weekend effect is studied. The results of this research will help to understand the underlying behavior of the photolysis rate constants when different atmospheric conditions are present.

  15. Meteorological Simulations of Ozone Episode Case Days during the 1996 Paso del Norte Ozone Study

    SciTech Connect

    Brown, M.J.; Costigan, K.; Muller, C.; Wang, G.

    1999-02-01

    Meteorological simulations centered around the border cities of El Paso and Ciudad Juarez have been performed during an ozone episode that occurred on Aug. 13,1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were petiormed using the HOTMAC mesoscale meteorological model using a 1,2,4, and 8 km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the Aug. 11-13 time period is emphasized in this paper. Comparison of model-produced wind speed profiles to rawirisonde and radar profiler measurements shows reasonable agreement. A persistent upper-level jet was captured in the model simulations through data assimilation. In the evening hours, the model was not able to produce the strong wind direction shear seen in the radar wind profiles. Based on virtual potential temperature profile comparisons, the model appears to correctly simulate the daytime growth of the convective mixed layer. However, the model underestimates the cooling of the surface layer at night. We found that the upper-level jet significantly impacted the turbulence structure of the boundary layer, leading to relatively high turbulent kinetic energy (tke) values aloft at night. The model indicates that these high tke values aloft enhance the mid-morning growth of the boundary layer. No upper-level turbulence measurements were available to verify this finding, however. Radar profiler-derived mixing heights do indicate relatively rapid morning growth of the mixed layer.

  16. Meteorological simulations of ozone episode case days during the 1996 Paso del Norte ozone study

    SciTech Connect

    Brown, M.J.; Costigan, K.; Muller, C.; Wang, G.

    1999-07-01

    Meteorological simulations centered around the border cities of El Paso and Ciudad Juarez have been performed during an ozone episode that occurred on Aug. 13, 1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were performed using the HOTMAC mesoscale meteorological model using a 1, 2, 4, and 8 km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the Aug. 11--13 time period is emphasized in this paper. Comparison of model-produced wind speed profiles to rawinsonde and radar profiler measurements shows reasonable agreement. A persistent upper-level jet was captured in the model simulations through data assimilation. In the evening hours, the model was not able to produce the strong wind direction shear seen in the radar wind profiles. Based on virtual potential temperature profile comparisons, the model appears to correctly simulate the daytime growth of the convective mixed layer. However, the model underestimates the cooling of the surface layer at night. The authors found that the upper-level jet significantly impacted the turbulence structure of the boundary layer, leading to relatively high turbulent kinetic energy (tke) values aloft at night. The model indicates that these high tke values aloft enhance the mid-morning growth of the boundary layer. No upper-level turbulence measurements were available to verify this finding, however. Radar profiler-derived mixing heights do indicate relatively rapid morning growth of the mixed layer.

  17. Sensitivity Modeling Study for an Ozone Occurrence during the 1996 Paso Del Norte Ozone Campaign

    PubMed Central

    Lu, Duanjun; Reddy, Remata S.; Fitzgerald, Rosa; Stockwell, William R.; Williams, Quinton L.; Tchounwou, Paul B.

    2008-01-01

    Surface ozone pollution has been a persistent environmental problem in the US and Europe as well as the developing countries. A key prerequisite to find effective alternatives to meeting an ozone air quality standard is to understand the importance of local anthropogenic emissions, the significance of biogenic emissions, and the contribution of long-range transport. In this study, an air quality modeling system that includes chemistry and transport, CMAQ, an emission processing model, SMOKE, and a mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of the 1996 Paso del Norte Ozone Campaign. The results show that the modeling system exhibits the capability to simulate this high ozone occurrence by providing a comparable temporal variation of surface ozone concentration at one station and to capture the spatial evolution of the event. Several sensitivity tests were also conducted to identify the contributions to high surface ozone concentration from eight VOC subspecies, biogenic VOCs, anthropogenic VOCs and long-range transportation of ozone and its precursors. It is found that the reductions of ETH, ISOP, PAR, OLE and FORM help to mitigate the surface ozone concentration, and like anthropogenic VOCs, biogenic VOC plays a nonnegligible role in ozone formation. But for this case, long-range transport of ozone and its precursors appears to produce an insignificant contribution. PMID:19190351

  18. Hydrocarbon source apportionment for the 1996 Paso del Norte Ozone Study.

    PubMed

    Fujita, E M

    2001-08-10

    The 1996 Paso del Norte (PdN) ozone study was conducted to improve current understanding of the significant meteorological and air quality processes that lead to high concentrations of ozone in El Paso, Texas (USA) and Ciudad Juárez, Chihuahua (Mexico). Two-hour canister samples were collected five times daily at 05.00-07.00 h, 07.00-09.00 h, 09.00-11.00 h, 11.00-13.00 h, and 15.00-17.00 h MST during intensive study periods at one urban and one rural site on each side of the border. An automated gas chromatograph was operated at one site in central El Paso. Source profiles (the fractional chemical composition of emissions) from motor vehicles, gasoline, liquefied petroleum gas, and commercial natural gas were combined with source profiles from other studies for input to the Chemical Mass Balance (CMB) receptor model to apportion the measured non-methane hydrocarbons (NMHC) to sources. On-road vehicle emissions accounted for one-half to two-thirds of the NMHC in Ciudad Juárez and El Paso with the highest contributions occurring during the morning and afternoon commute periods. Emissions from diesel exhaust contributed approximately 2-3% of NMHC in Ciudad Juárez and less than 2% in El Paso. The average sum of liquid gasoline and gasoline vapor increased during the day in Ciudad Juárez from 2% at 06.00 h to approximately 12% at 16.00 h. Diurnal and day-of-the-week patterns in the liquid gasoline contributions are essentially identical to the corresponding patterns for motor vehicle exhaust, which suggest that a large fraction of the liquid gasoline contribution may be associated with tailpipe emissions rather than evaporative emissions from motor vehicles or industrial sources. Including the sum of the two sources put the upper limit for tailpipe contributions at 60-70% of NMHC. PMID:11516134

  19. GIS based Relative Tsunami Hazard Maps for Northern California, Humboldt and Del Norte Counties

    NASA Astrophysics Data System (ADS)

    Patton, J. R.; Dengler, L. A.

    2004-12-01

    Tsunami hazard maps are generated using a geographical information systems (GIS) approach to depict the relative tsunami hazard of coastal Humboldt and Del Norte Counties in northern California. Maps are composed for the Humboldt Bay, Eel River, and Crescent City regions and available online at http://www.humboldt.edu/~geodept/earthquakes/rctwg/toc.html . In contrast to previous mapping efforts that utilize a single line to represent inundation, hazard is displayed gradationally. A 2.5D surface is constructed to represent this hazard. Elevation, normally used for 2.5D surfaces, is substituted with hazard units. Criteria boundaries are used to separate regions of increasing hazard. Criteria boundaries are defined based on numerical modeling, paleoseismic studies, historical flooding, FEMA Q3 flood maps, and impacts of recent tsunamis elsewhere. Zones are constructed to further adjust the criteria with respect to a physically determined variable hazard (e.g. proximity to open ocean). A triangular irregular network (TIN) is constructed using hazard criteria boundaries as breaklines. Fabricated points are necessary to construct a hazard surface and are placed where criteria boundaries diverge or where hazard is nonlinear between criteria boundaries. Hazard is displayed as a continuous gradational color scale ranging from red (high hazard) through orange (medium), yellow (low) to gray (no hazard). The maps are GIS based to facilitate ready adaptation by planners and emergency managers. The maps are intended for educational purposes, to improve awareness of tsunami hazards and to encourage emergency planning efforts of local and regional organizations by illustrating the range of possible tsunami events.

  20. Hydrocarbon source apportionment for the 1996 Paso del Norte ozone study

    SciTech Connect

    Fujita, E.M.

    1999-07-01

    This paper provides a summary of the nonmethane hydrocarbon (NMHC) source apportionments performed at Desert Research Institute as part of the 1996 Paso del Norte Ozone Study. Version 8 of the Chemical Mass Balance (CMB) receptor model was applied to a total of 2232 hourly automated gas chromatography (auto-GC) and 225 two-hour canister samples. The auto-GC system was operated by the Texas Natural Resource Conservation Commission at one site in central El Paso. Two-hour canister samples were collected five times per day at 0500--0700, 0700--0900, 0900--1100, 1100--1300, and 1500--1700 MST during intensive study periods at one urban and one rural site on each side of the border. Gasoline vehicle exhaust accounts for one-half to two-thirds of NMHC in Juarez and El Paso with highest contributions during the morning and afternoon commute periods. Emissions from diesel exhaust and propane buses are both 2 to 5% of NMHC in Juarez and less than 2% in El Paso. The average sum of liquid gasoline and gasoline vapor increases during the day in Juarez from 2% at 0600 to about 8% at 1600. Diurnal and day-of-the-week patterns in the liquid gasoline contributions are essentially identical to the corresponding patterns for motor vehicle exhaust. These patterns suggest that a large fraction of the liquid gasoline contribution is associated with tailpipe emissions rather than evaporative emissions from either vehicle or industrial sources. Additionally, the contributions of liquid gasoline are strongly correlated with vehicle exhaust with respect to wind direction. The sum of the two sources put the upper limit for tailpipe contributions at 60 to 70%t of NMHC.

  1. Characterization of ambient particulate matter in the Paso del Norte region

    SciTech Connect

    Li, W.W.; Currey, R.M.; Valenzuela, V.H.; Meuzelaar, H.L.C.; Sheya, S.A.; Anderson, J.R.; Banerjee, S.; Griffin, J.B.

    1999-07-01

    Air pollution in the Paso del Norte region, where West Texas abuts the southern boundary of New Mexico and the northern boundary of Chihuahua, Mexico is a common concern to the residents on both sides of the border. Parts of the region fail to meet the US and Mexican Ambient Air Quality Standards for particulate matter, ozone, and carbon monoxide. The regional air pollution problem is complicated due to arid climate, complex terrain topography, frequently occurring temperature inversions, extensive unpaved urban areas, an aging and poorly maintained vehicle fleet, and a number of other uncontrolled anthropogenic emission sources. The issue is further complicated by concerns arising from recent scientific evidence of the health effects associated with exposures to fine particulate matter. A study designed to address particulate matter (PM) air pollution problems in the region is currently undertaken by researchers from member universities of the Southwest Center for Environmental Research and Policy and several governmental agencies. The study attempts to (1) characterize the fine fraction of PM; (2) identify and characterize the major regional emission sources; (3) apportion the fine fraction of PM to the source emissions; and (4) establish a regional technological information clearinghouse. The short-term goal of this research is to initiate a research program to characterize, identify, and quantify the sources and nature of the PM in the region. The long-term goal of this study is to establish regional research capabilities to continue air quality monitoring, evaluation, modeling, and control after the implementation of the study. A scoping study to collect regional PM was conducted in December 1998.

  2. Compilation and evaluation of a Paso del Norte emission inventory for use in photochemical dispersion modeling

    SciTech Connect

    Haste, T.L.; Kumar, N.; Chinkin, L.R.; Roberts, P.T.; Saeger, M.; Mulligan, S.; Yarbrough, J.

    1999-07-01

    Emission inventories are routinely used for planning purposes and as input to comprehensive photochemical air quality models. Photochemical model performance and the development of an effective control strategy are predicated on the accuracy of an underlying emission inventory. The purpose of this study was to compile an ozone precursor emission inventory for the El Paso/Ciudad Juarez/Southern Dona Ana region; generate a spatially and temporally resolved, speciated emission inventory; and evaluate the accuracy and representativeness of the inventory. Existing point, area, and mobile source emissions data were obtained from local government agencies. Emissions were spatially and temporally allocated to a gridded domain using region-specific demographic and land cover information. The inventory was processed using the US Environmental Protection Agency (EPA) recommended Urban Airshed Model Emissions Preprocessor System 2.0 (UAM-EPS 2.0) which generates emissions files that can be directly used as input to the Urban Airshed Model. An evaluation of the emission inventory was then performed by comparing inventory non-methane hydrocarbon (NMHC)/NO{sub x} and CO/NO{sub x} ratios to ambient ratios using air quality data collected during the 1996 Paso del Norte Ozone Study. Detailed NMHC species comparisons were also made in order to investigate the relative composition of individual hydrocarbon species in the emission inventory and in the ambient data. This initial emission inventory is expected to undergo substantial revisions during the upcoming photochemical modeling phase of the effort to better understand and improve the air quality of the El Paso/Ciudad Juarez/Southern Dona Ana region.

  3. The 1996 and 1997 Paso del Norte ozone studies: An overview of the field studies and data analyses

    SciTech Connect

    MacDonald, C.P.; Roberts, P.T.; Main, H.H.; Dye, T.S.; Coe, D.L.; Yarbrough, J.

    1999-07-01

    This paper summarizes the measurement campaigns of the 1996 and 1997 Paso del Norte Ozone Studies, the resultant data sets, and the findings and conclusions that arose from subsequent data analyses. The purpose of these data analyses was to develop an understanding of the significant chemical and physical processes that lead to high concentrations of ozone in the Paso del Norte study region which includes El Paso, TX; Sunland Park, NM; and Juarez, Mexico. High ozone concentrations resulted from a combination of conditions, including slow convective boundary layer (CBL) growth, reduced CBL depth, light surface winds, and high concentrations of ozone precursor at ground level in the morning. Synoptic-scale meteorological conditions observed during high ozone episodes included an upstream aloft high-pressure system, and aloft warming. Aloft carryover of ozone and ozone precursors did not significantly contribute to the surface ozone concentration. Furthermore, hydrocarbon and NO{sub x} data, although spatially limited, showed that the system is more often NO{sub x}-limited rather than VOC-limited.

  4. Modified Team-Based Learning Strategy to Improve Human Anatomy Learning: A Pilot Study at the Universidad Del Norte in Barranquilla, Colombia

    ERIC Educational Resources Information Center

    Martínez, Emilio G.; Tuesca, Rafael

    2014-01-01

    As part of an institutional program sponsored by the Centre for Teaching Excellence at the Universidad del Norte, Barranquilla, Colombia, we developed an educational research study on two sessions of human anatomy in which we combined team-based learning (TBL) and the use of iPads. Study data included the TBL, assessments applied during the…

  5. Copper uptake by Pteris melanocaulon Fée from a Copper-Gold mine in Surigao del Norte, Philippines.

    PubMed

    De la Torre, Joseph Benjamin B; Claveria, Rene Juna R; Perez, Rubee Ellaine C; Perez, Teresita R; Doronila, Augustine I

    2016-01-01

    The ability of some plants to take up metal contaminants in the soil has been of increasing interest as an environmental approach to pollution clean-up. This study aimed to assess the ability of Pteris melanocaulon for copper(Cu) uptake by determining the Cu levels in the fern vis-à-vis surrounding soil and the location of Cu accumulation within its biomass. It also aimed to add information to existing literature as P. melanocaulon are found to be less documented compared to other fern metal accumulators, such as P. vittata. The P. melanocaulon found in the Suyoc Pit of a Copper-Gold mine in Placer, Surigao del Norte, Philippines exhibited a high Bioaccumulation Factor(BF) of 4.04 and a low Translocation Factor(TF) of 0.01, suggesting more Cu accumulation in the roots (4590.22 ± 385.66 µg g(-1) Cu). Noteworthy was the Cu concentration in the rhizome which was also high (3539.44 ± 1696.35 µg g(-1) Cu). SEM/EDX analyses of the Cu content in the roots indicated high elemental %Cu in the xylem (6.95%) than in the cortex (2.68%). The high Cu content in the roots and rhizomes and the localization of Cu in the xylem manifested a potential utilization of the fern as a metallophyte for rhizofiltration and phytostabilization. PMID:26555556

  6. The effect of urban canopy parameterizations on mesoscale meteorological model simulations in the Paso del Norte area

    SciTech Connect

    Brown, M.J.; Williams, M.D.

    1997-04-01

    Since mesoscale numerical models do not have the spatial resolution to directly simulate the fluid dynamics and thermodynamics in and around urban structures, urban canopy parameterizations are sometimes used to approximate the drag, heating, and enhanced turbulent kinetic energy (tke) produced by the sub-grid scale urban elements. In this paper, we investigate the effect of the urban canopy parameterizations used in the HOTMAC mesoscale meteorological model by turning the parameterizations on and off. The model simulations were performed in the Paso del Norte region, which includes the cities of El Paso and Ciudad Juarez, the Franklin and Sierra Juarez mountains, and the Rio Grande. The metropolitan area is surrounded by relatively barren scrubland and is intersected by strips of vegetation along the Rio Grande. Results indicate that the urban canopy parameterizations do affect the mesoscale flow field, reducing the magnitude of wind speed and changing the magnitude of the sensible heat flux and tke in the metropolitan area. A nighttime heat island and a daytime cool island exist when urban canopy parameters are turned on, but associated recirculation flows are not readily apparent. Model-computed solar, net, and longwave radiation values look reasonable, agreeing for the most part with published measurements.

  7. Seroprevalence of select bloodborne pathogens and associated risk behaviors among injection drug users in the Paso del Norte region of the United States – Mexico border

    PubMed Central

    Baumbach, Joan P; Foster, Lily N; Mueller, Mark; Cruz, Michelle Firestone; Arbona, Sonia; Melville, Sharon; Ramos, Rebeca; Strathdee, Steffanie A

    2008-01-01

    Background The region situated where the borders of Mexico, Texas and New Mexico meet is known as 'Paso del Norte'. The Paso del Norte Collaborative was formed to study the seroprevalence of select pathogens and associated risk behaviors among injection drug users (IDUs) in the region. Methods Respondent-driven sampling (RDS) was used: 459 IDU participants included 204 from Mexico; 155 from Texas; and 100 from New Mexico. Each of the three sites used a standardized questionnaire that was verbally administered and testing was performed for select bloodborne infections. Results Participants were mostly male (87.4%) and Hispanic/Latino (84.7%) whose median age was 38. In Mexico, Texas and New Mexico, respectively: hepatitis B virus (HBV) was seen in 88.3%, 48.6% and 59.6% of participants; hepatitis C virus (HCV) in 98.7%, 76.4% and 80.0%; human immunodeficiency virus (HIV) in 2.1%, 10.0% and 1.0%; and syphilis in 4.0%, 9.9% and 3.0%. Heroin was the drug injected most often. More IDUs in New Mexico were aware of and used needle exchange programs compared with Texas and Mexico. Conclusion There was mixed success using RDS: it was more successfully applied after establishing good working relationships with IDU populations. Study findings included similarities and distinctions between the three sites that will be used to inform prevention interventions. PMID:19014605

  8. Attic Dust Analysis Approach for Evaluation of Heavy Metal Deposition on the El Paso Del Norte Region

    NASA Astrophysics Data System (ADS)

    Shekhter, E. G.; van Pelt, S.; Pannell, K.; Gill, T. E.; Barnes, M. A.

    2010-12-01

    The El Paso del Norte region in the United States is a region of complex topography that is the home to more than 2 million people who share the same air. A large non-ferrous smelter (primary lead-copper smelter),owned by the American Smelting and Refining Company (ASARCO), was functioning in the Rio Grande River valley on the west side of the Franklin Mountains that divide the city of El Paso and across the river from Juarez, Mexico’s largest city on the United States border. During the more than 100 years of operation, beginning in 1887, the ASARCO smelter emissions considerably deteriorated the already complex environmental condition on the US-Mexican border. In order to identify the sources and patterns of heavy metal dispersion, we used an attic dust analyses approach which has not been previously been applied in this area. Undisturbed attic dust can provide an integrated history of atmospheric loading of particulates emanating from geological, biological and anthropogenic sources and can help to reconstruct the air pollution history on a local scale. We sampled attic dust and dust from undisturbed surfaces in 15 buildings of varying ages from three neighborhoods in the cities of El Paso and Juarez. The dust samples and samples of unpolluted buried soil horizons in the area were extracted with aqua regia and analyzed by ICP-AES and ICP-MS. Enrichment ratios (ER) were calculated by dividing the concentration of a trace metal in the attic dust by the mean concentration of the same element in the buried soil horizons. Mean ER for Pb were 263.3, 95.4, and 70.2 for dust collected in a neighborhood near the smelter, downtown Juarez, and an El Paso neighborhood on the other side of the Franklin Mountains from the smelter. Greater ER for As, Cd, Zn, Sb, and Cu followed the same trends, by neighborhood, noted for Pb. In addition, dust collected from attics surfaces (pipes, ducts, storage containers) post-dating smelter disclosure had lower ER for the trace metals

  9. Aryl hydrocarbon receptor-mediated activity of particulate organic matter from the Paso del Norte airshed along the U.S.-Mexico border.

    PubMed Central

    Arrieta, Daniel E; Ontiveros, Cynthia C; Li, Wen-Whai; Garcia, Jose H; Denison, Michael S; McDonald, Jacob D; Burchiel, Scott W; Washburn, Barbara Shayne

    2003-01-01

    In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 micro m in aerodynamic diameter (PM10) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-(O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.25 pmol/min/mg protein) and luciferase activities (994 relative light units/mg) were highest in extracts from the Advance site located in an industrial neighborhood in Juarez. These values represented 58% and 55%, respectively, of induction associated with 1 micro M ss-naphthoflavone exposures. In contrast, little activity was observed at the Northeast Clinic site in El Paso, the reference site. In most cases, luciferase and EROD activity from extracts collected from the Tillman Health Center site, situated in downtown El Paso, fell between those observed at the other two sites. Overall, a statistically significant correlation existed between PM10 and EROD and luciferase activities. Chemical analysis of extracts collected from the Advance site demonstrated that concentrations of most PAHs were higher than those reported in most other metropolitan areas in the United States. Calculations made with these data suggest a cancer risk of 5-12 cases per 100,000 people. This risk estimate, as well as comparisons with the work of other investigators, raises concern regarding the potential for adverse health effects to the residents of this airshed. Further work is needed to understand the sources, exposure, and effects of PM10 and particulate organic material in the Paso del Norte airshed. PMID:12896850

  10. Water-quality data for the Rio Grande between Picacho Bridge near Las Cruces and Calle del Norte Bridge near Mesilla, New Mexico, 1996-97

    USGS Publications Warehouse

    Huff, G.F.

    1998-01-01

    The City of Las Cruces is concerned about water quality in a reach of the Rio Grande that receives outfall from the City of Las Cruces wastewater-treatment plant. Water-quality samples were collected from the Rio Grande at Picacho Bridge near Las Cruces, New Mexico; from the sampling site at the City of Las Cruces wastewater-treatment plant; and from the Rio Grande at Calle del Norte Bridge near Mesilla, New Mexico. The samples were collected on 12 days from August 6, 1996, to February 28, 1997, and were analyzed for a suite of dissolved and total constituents including trace metals. Instantaneous stream discharge was measured concurrently with collection of the Rio Grande samples. At the wastewater- treatment plant, the City of Las Cruces provided instantaneous discharge rates concurrent with sampling. Quality-control measures used in this study to ensure analytical accuracy included replicate sampling, replicate analysis of split samples, ambient blanks, equipment blanks, and analysis of standard reference water samples.

  11. Mapping of High Value Crops Through AN Object-Based Svm Model Using LIDAR Data and Orthophoto in Agusan del Norte Philippines

    NASA Astrophysics Data System (ADS)

    Candare, Rudolph Joshua; Japitana, Michelle; Cubillas, James Earl; Ramirez, Cherry Bryan

    2016-06-01

    This research describes the methods involved in the mapping of different high value crops in Agusan del Norte Philippines using LiDAR. This project is part of the Phil-LiDAR 2 Program which aims to conduct a nationwide resource assessment using LiDAR. Because of the high resolution data involved, the methodology described here utilizes object-based image analysis and the use of optimal features from LiDAR data and Orthophoto. Object-based classification was primarily done by developing rule-sets in eCognition. Several features from the LiDAR data and Orthophotos were used in the development of rule-sets for classification. Generally, classes of objects can't be separated by simple thresholds from different features making it difficult to develop a rule-set. To resolve this problem, the image-objects were subjected to Support Vector Machine learning. SVMs have gained popularity because of their ability to generalize well given a limited number of training samples. However, SVMs also suffer from parameter assignment issues that can significantly affect the classification results. More specifically, the regularization parameter C in linear SVM has to be optimized through cross validation to increase the overall accuracy. After performing the segmentation in eCognition, the optimization procedure as well as the extraction of the equations of the hyper-planes was done in Matlab. The learned hyper-planes separating one class from another in the multi-dimensional feature-space can be thought of as super-features which were then used in developing the classifier rule set in eCognition. In this study, we report an overall classification accuracy of greater than 90% in different areas.

  12. Cytotoxic responses and potential respiratory health effects of carbon and carbonaceous nanoparticulates in the Paso del Norte airshed environment.

    PubMed

    Soto, K F; Murr, L E; Garza, K M

    2008-03-01

    We have utilized a range of manufactured or commercial nanoparticulate materials, including surrogate carbon nano-PM along with combustion-generated carbonaceous (soot) nano-PM characteristic of environmental nano- PM (both indoor and outdoor) to investigate and compare their cytotoxic response in vitro with an immortalized human epithelial (lung model) cell line (A549). These have included nano-Ag, Al2O3, TiO2, Fe2O3, ZrO2, Si3N4, chrysotile asbestos, BC, 2 types of MWCNT-aggregate PM (MWCNT-R and MWCNT-N), and high-volume glass fiber collected soots: candle, wood, diesel (truck), tire, and 3-types of natural gas kitchen burner-generated soots: yellow (fuel-rich) flame, low-flow blue flame, and normal flow blue flame soot PM. These carbonaceous nano-PM species can be found in either the indoor and outdoor environments or microenvironments. Two-day and two-week in-vitro cultures of A549 showed cell death (or decreased cell viability) for all nanoparticulate materials, but especially significant for all but the TiO2 and candle, wood, and diesel PM. The natural gas kitchen burner combustion PM cell death response was characteristic of BC and MWCNT PM. There was no correlation with total PAH content of the soot PM. Cytokine release (IL-6, IL-8) was detected for the Ag, Fe2 O3, asbestos, BC and the MWCNT PM. Reactive oxygen species (ROS) production was also detected for Ag, Fe2 O3, ZrO2, asbestos, BC, and the MWCNT aggregate PM, as well as the natural gas kitchen burner combustion PM. TEM, FESEM, and optical microscopy examination of these nanomaterials illustrate the wide range in PM morphologies and crystallinities as well as cell morphologies. Taken together, these results illustrate proinflammatory and related respiratory health issues in relation to environmental nanoparticulates. PMID:18441401

  13. Cytotoxic Responses and Potential Respiratory Health Effects of Carbon and Carbonaceous Nanoparticulates in the Paso del Norte Airshed Environment

    PubMed Central

    Soto, K. F.; Murr, L. E.; Garza, K. M.

    2008-01-01

    We have utilized a range of manufactured or commercial nanoparticulate materials, including surrogate carbon nano-PM along with combustion-generated carbonaceous (soot) nano-PM characteristic of environmental nano-PM (both indoor and outdoor) to investigate and compare their cytotoxic response in vitro with an immortalized human epithelial (lung model) cell line (A549). These have included nano-Ag, Al2O3, TiO2, Fe2O3, ZrO2, Si3N4, chrysotile asbestos, BC, 2 types of MWCNT-aggregate PM (MWCNT-R and MWCNT-N), and high-volume glass fiber collected soots: candle, wood, diesel (truck), tire, and 3-types of natural gas kitchen burner-generated soots: yellow (fuel-rich) flame, low-flow blue flame, and normal flow blue flame soot PM. These carbonaceous nano-PM species can be found in either the indoor and outdoor environments or microenvironments. Two-day and two-week in-vitro cultures of A549 showed cell death (or decreased cell viability) for all nanoparticulate materials, but especially significant for all but the TiO2 and candle, wood, and diesel PM. The natural gas kitchen burner combustion PM cell death response was characteristic of BC and MWCNT PM. There was no correlation with total PAH content of the soot PM. Cytokine release (IL-6, IL-8) was detected for the Ag, Fe2 O3, asbestos, BC and the MWCNT PM. Reactive oxygen species (ROS) production was also detected for Ag, Fe2 O3, ZrO2, asbestos, BC, and the MWCNT aggregate PM, as well as the natural gas kitchen burner combustion PM. TEM, FESEM, and optical microscopy examination of these nanomaterials illustrate the wide range in PM morphologies and crystallinities as well as cell morphologies. Taken together, these results illustrate proinflammatory and related respiratory health issues in relation to environmental nanoparticulates. PMID:18441401

  14. Investigating the relationship between climate teleconnection patterns and soil moisture variability in the Rio Grande/Río Bravo del Norte basin using the NOAH land surface model

    NASA Astrophysics Data System (ADS)

    Khedun, C. P.; Mishra, A. K.; Bolten, J. D.; Giardino, J. R.; Singh, V. P.

    2010-12-01

    Soil moisture is an important component of the hydrological cycle. Climate variability patterns, such as the Pacific Decadal Oscillation (PDO), El Niño Southern Oscillation (ENSO), and Atlantic Multidecadal Oscillation (AMO) are determining factors on surface water availability and soil moisture. Understanding this complex relationship and the phase and lag times between climate events and soil moisture variability is important for agricultural management and water planning. In this study we look at the effect of these climate teleconnection patterns on the soil moisture across the Rio Grande/Río Bravo del Norte basin. The basin is transboundary between the US and Mexico and has a varied climatology - ranging from snow dominated in its headwaters in Colorado, to an arid and semi-arid region in its middle reach and a tropical climate in the southern section before it discharges into the Gulf of Mexico. Agricultural activities in the US and in northern Mexico are highly dependent on the Rio Grande and are extremely vulnerable to climate extremes. The treaty between the two countries does not address climate related events. The soil moisture is generated using the community NOAH land surface model (LSM). The LSM is a 1-D column model that runs in coupled or uncoupled mode, and it simulates soil moisture, soil temperature, skin temperature, snowpack depth, snow water equivalent, canopy water content, and energy flux and water flux of the surface energy and water balance. The North American Land Data Assimilation Scheme 2 (NLDAS2) is used to drive the model. The model is run for the period 1979 to 2009. The soil moisture output is validated against measured values from the different Soil Climate Analysis Network (SCAN) sites within the basin. The spatial and temporal variability of the modeled soil moisture is then analyzed using marginal entropy to investigate monthly, seasonal, and annual variability. Wavelet transform is used to determine the relation, phase

  15. PASO DEL NORTE ENVIRONMENTAL MONITOR

    EPA Science Inventory

    This project is developing an Internet web site and associated community linkages to provide relevant-time air quality and local traffic and transit information, in English and Spanish, to the international communities of El Paso, Texas, Sunland Park, New Mexico and Ciud...

  16. Evaluation of emission control strategies to reduce ozone pollution in the Paso del Norte region using a photochemical air quality modeling system

    NASA Astrophysics Data System (ADS)

    Valenzuela, Victor Hugo

    variability of the PREDICTED to OBSERVED ozone concentrations of both BASELINE model and simulations with modified emissions assessed by the sensitivity analysis. All simulations were found to vary within acceptable ranges of these two criteria variables. Simulation results indicate ozone formation in the PdN region is VOC-limited. Under VOC-limited conditions, modifications to NOx emissions do not produce a marked increase or decrease in ozone concentrations. Modifications to VOC emissions generated the highest variability in ozone concentrations. Increasing VOC emissions by 75% produced results which minimized model bias and error when comparing PREDICTED and OBSERVED ozone concentrations. Increasing VOC emissions by 75% either alone or in combination with a 75% increase in NOx emissions generated PREDICTED ozone concentrations very near to OBSERVED ozone. By evaluating the changes in ambient ozone concentrations through photochemical modeling, air quality planners may identify the most efficient or effective VOC emissions control strategies for area sources. Among the strategies to achieve emissions reductions are installation of gasoline vapor recovery systems, replacing high-pressure low-volume surface coating paint spray guns with high-volume low-pressure spray paint guns, requiring emissions control booths for surface coating operations as well as undertaking solvent management practices, requiring the sale of low VOC paint solvents in the surface-coating industry, and requiring low-VOC solvents in the dry cleaning industry. Other strategies to reduce VOC emissions include initiating Eco-Driving strategies to reduce fuel consumption from mobile sources and minimize vehicle idling at the international ports of entry by reducing bridge wait times. This dissertation depicts a tool for evaluating impacts of emissions on regional air quality by addressing the highly unresolved fugitive emissions in the Paso del Norte region. It provides a protocol for decision makers to

  17. Extensión del Formalismo de Orbitales de Defecto Cuántico al tratamiento del efecto Stark (SQDO).

    NASA Astrophysics Data System (ADS)

    Menéndez, J. M.; Martín, I.; Velasco, A. M.

    El estudio experimental de las interacciones de átomos Rydberg altamente excitados con campos eléctricos ha experimentado un creciente interés durante las dos últimas décadas debido, en gran medida, al desarrollo de nuevas técnicas para crear y estudiar átomos Rydberg en el laboratorio. Acompañando a estas nuevas técnicas experimentales, es necesario el desarrollo de modelos teóricos que nos permitan contrastar sus medidas y conocer mejor los fundamentos de los mismos. Desde el punto de vista teórico el conocimiento del desdoblamiento de los niveles energéticos de un átomo en función de la magnitud del campo eléctrico aplicado (lo que se conoce como mapa Stark) es el mejor punto de partida para la descripción del sistema y un prerrequisito fundamental para el cálculo de distintas propiedades atómicas en presencia del campo eléctrico tales como intensidades de transición, umbrales de ionización de campo eléctrico, tiempos de vida, posición y anchura de cruces evitados, etc. En este trabajo presentamos la adaptación del método de orbitales de defecto cuántico [1,2,3] al tratamiento del efecto Stark (SQDO) [4] y su aplicación al cálculo de los desdoblamientos energéticos y fuerzas de oscilador de estados Rydberg en los átomos de Li, Na y K. El propósito de este estudio es, por un lado, desarrollar métodos fiables para la determinación de propiedades atómicas en presencia de campos eléctricos y, por otro, mostrar la fiabilidad de las funciones de onda QDO en la descripción del efecto Stark en sistemas atómicos.

  18. Streamflow gains and losses and selected water-quality observations in five subreaches of the Rio Grande/Rio Bravo del Norte from near Presidio to Langtry, Texas, Big Bend area, United States and Mexico, 2006

    USGS Publications Warehouse

    Raines, Timothy H.; Turco, Michael J.; Connor, Patrick J.; Bennett, Jeffery B.

    2012-01-01

    Few historical streamflow and water-quality data are available to characterize the segment of the Rio Grande/Rio Bravo del Norte (hereinafter Rio Grande) extending from near Presidio to near Langtry, Texas. The U.S. Geological Survey, in cooperation with the National Park Service and the Texas Commission on Environmental Quality, collected water-quality and streamflow data from the Rio Grande from near Presidio to near Langtry, Texas, to characterize the streamflow gain and loss and selected constituent concentrations in a 336.3-mile reach of the Rio Grande from near Presidio to near Langtry, Texas. Streamflow was measured at 38 sites and water-quality samples were collected at 20 sites along the Rio Grande in February, March, and June 2006. Streamflow gains and losses over the course of the stream were measured indirectly by computing the differences in measured streamflow between sites along the stream. Water-quality data were collected and analyzed for salinity, dissolved solids, major ions, nutrients, trace elements, and stable isotopes. Selected properties and constituents were compared to available Texas Commission on Environmental Quality general use protection criteria or screening levels. Summary statistics of selected water-quality data were computed for each of the five designated subreaches. Streamflow gain and loss and water-quality constituent concentration were compared for each subreach, rather than the entire segment because of the temporal variation in sample collection caused by controlled releases upstream. Subreach A was determined to be a losing reach, and subreaches B, C, D, and E were determined to be gaining reaches. Compared to concentrations measured in upstream subreaches, downstream subreaches exhibited evidence of dilution of selected constituent concentrations. Subreaches A and B had measured total dissolved solids, chloride, and sulfate exceeding the Texas Commission on Environmental Quality general use protection criteria

  19. Aztecas Del Norte: The Chicanos of Aztlan.

    ERIC Educational Resources Information Center

    Forbes, Jack D.

    The purpose of this book is to examine the Indian heritage of the Mexican Americans of the Southwest. It covers Mexican American history from the time of the Aztecs to the present. In the introduction, the Mexican approach to United States history is discussed. Topics covered are: the Tollecayotl and Mexicayotl heritage; the northward movement;…

  20. Mesohabitats, fish assemblage composition, and mesohabitat use of the Rio Grande silvery minnow over a range of seasonal flow regimes in the Rio Grande/Rio Bravo del Norte, in and near Big Bend National Park, Texas, 2010-11

    USGS Publications Warehouse

    Moring, J. Bruce; Braun, Christopher L.; Pearson, Daniel K.

    2014-01-01

    In 2010–11, the U.S. Geological Survey (USGS), in cooperation with the U.S. Fish and Wildlife Service, evaluated the physical characteristics and fish assemblage composition of mapped river mesohabitats at four sites on the Rio Grande/Rio Bravo del Norte (hereinafter Rio Grande) in and near Big Bend National Park, Texas. The four sites used for the river habitat study were colocated with sites where the U.S. Fish and Wildlife Service has implemented an experimental reintroduction of the Rio Grande silvery minnow (Hybognathus amarus), a federally listed endangered species, into part of the historical range of this species. The four sites from upstream to downstream are USGS station 08374340 Rio Grande at Contrabando Canyon near Lajitas, Tex. (hereinafter the Contrabando site), USGS station 290956103363600 Rio Grande at Santa Elena Canyon, Big Bend National Park, Tex. (hereinafter the Santa Elena site), USGS station 291046102573900 Rio Grande near Ranger Station at Rio Grande Village, Tex. (hereinafter the Rio Grande Village site), and USGS station 292354102491100 Rio Grande above Stillwell Crossing near Big Bend National Park, Tex. (hereinafter the Stillwell Crossing site). In-channel river habitat was mapped at the mesohabitat scale over a range of seasonal streamflows. A late summer (August–September 2010) high-flow regime, an early spring (April–May 2010) intermediate flow regime, and a late spring (May 2011) low-flow regime were the seasonal flows used in the study. River habitat was mapped in the field by using a geographic information system and a Global Positioning System unit to characterize the sites at the mesohabitat scale. Physical characteristics of a subset of mesohabitats in a reach of the Rio Grande at each site were measured during each flow regime and included depth, velocity, type and size of the substrate, and percent embeddedness. Selected water-quality properties (dissolved oxygen, pH, specific conductance, and temperature) of a subset of

  1. "El Norte," Deracination and Circularity: An Epic Gone Awry

    ERIC Educational Resources Information Center

    Brakel, Arthur

    2007-01-01

    Early journalistic reviews (e.g., Gold, Ebert, and Kael) of "El Norte" (1983), Gregory Nava's first major film, identify it as an epic. In "El Norte" the siblings Enrique and Rosa, two Guatemalan Amerindians, leave their native village on a quest to what for them is the mythical land in the North. Although "El Norte" corresponds to the general…

  2. Tratamiento del cáncer sin daño al corazón

    Cancer.gov

    Investigadores de los campos de oncología y de cardiología están trabajando para encontrar formas de impedir, manejar y posiblemente aun revertir los efectos secundarios cardiovasculares de ciertas terapias del cáncer.

  3. Contribución al flujo infrarrojo de las estrellas Be de la recombinación dielectrónica del MgII

    NASA Astrophysics Data System (ADS)

    Cruzado, A.; di Rocco, H.; Ringuelet, A.

    Para evaluar la contribución del proceso de recombinación dielectrónica del átomo de MgII al exceso de flujo infrarrojo observado en las estrellas Be, calculamos la energía emitida en las líneas originadas por este proceso. Se evaluaron los efectos de las condiciones físicas del medio, como la temperatura electrónica y la densidad electrónica, sobre el flujo emitido. Se consideró también la influencia de una posible opacidad.

  4. Preguntas para hacerle al doctor acerca del cáncer

    Cancer.gov

    Serie de preguntas, organizadas por tema, que los pacientes con cáncer pueden hacer al médico o a otros miembros de su equipo de atención médica para conocer más acerca de su tipo de cáncer y lo que pueden esperar.

  5. 75 FR 21220 - Del Norte Resource Advisory Committee (RAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... Rivers National Forest, 1330 Bayshore Way, Eureka, CA 95503 (707) 441-3673; e-mail jranieri@fs.fed.us... of Meeting Ground Rules and Operational Guidelines, (2) Discussion and decision on filling vacant replacement positions, (3) Process for soliciting project proposals and timeline, (4) Discuss on...

  6. Estudio del Hidrógeno neutro en dirección al remanente de supernova W28

    NASA Astrophysics Data System (ADS)

    Dubner, G.; Velazquez, P.; Green, A.; Goss, W. M.; Reynoso, E.

    Se presenta un relevamiento del hidrógeno neutro alrededor del remanente de supernova W28 realizado con el radiotelescopio australiano de Parkes. Se analizan rasgos de emisión y absorción. Se muestra la existencia de estructuras anulares asociadas con el remanente. Se compara la distribución del hidrógeno neutro con la ubicación de máseres de OH detectados en la línea de 1720 MHz.

  7. Petrophysical characterization of the Carito Norte, Mulata and Carito fields, Norte de Monagas, Eastern Venezuela

    SciTech Connect

    Porras, J.C.; De J. Valle,

    1996-08-01

    The Norte de Monagas trend is located in the Eastern Venezuelan Basin and is characterized by high temperature, high initial pressure and production rates, variable PVT properties, GORs, and asphaltene content, and the presence of a tar mat at the base of the oil column. These reservoirs were petrophysically characterized through the integration of core and log data. Productive sands are composed of very coarse- to medium-grained sands deposited primarily in deltaic to shallow marine environments. These sands are quartz-rich, with clay matrix averaging 3% in the Oligocene and 6% in the Cretaceous. The main difference is the presence of up to 30% feldspars in the Cretaceous. Clay mineralogy is dominated by illitic material in the Cretaceous and by kaolinite in the Oligocene. Post-depositional changes dominated by cementation, mechanical compaction and subsequent dissolution processes have resulted in marked improvement or degradation of the productive characteristics of these reservoirs. Rocks were divided into four petrophysical. categories based on grain size, pore throat radius, porosity and permeability. Mercury saturation vs. mercury saturation over capillary pressure plots show the dominant interconnected pore system which controls flow rates is best defined by 50% saturation. Plots constructed using R50 pore aperture correlation indicate the pore throats to be macro to mega porous. Average log calculated water saturation is 14% compared with estimated from capillary pressure data of 12% at 1200{prime} above free water level, and 15% from relative permeability data. Relative permeability data indicate the rocks behave preferably as water-wet.

  8. Historia Verdadera del Chicano del Norte. [True History of the Chicano of the North].

    ERIC Educational Resources Information Center

    Herrera, David; Bryan, Clifford E.

    Very little is known about the Chicanos in the northern U.S., especially those in the Northwest. Research and writing on Chicanos have concentrated on the Southwest or large urban settings, thus excluding those Chicanos residing in rural settings except for those in the migrant stream. These rural residents have become a forgotten people,…

  9. Weathering profiles in granites, Sierra Norte (Córdoba, Argentina)

    NASA Astrophysics Data System (ADS)

    Kirschbaum, Alicia; Martínez, Estela; Pettinari, Gisela; Herrero, Silvana

    2005-09-01

    Two weathering profiles evolved on peneplain-related granites in Sierra Norte, Córdoba province, were examined. Several weathering levels, of no more than 2 m thickness, were studied in these profiles. They had developed from similar parent rock, which had been exposed to hydrothermal processes of varying intensity. Fracturing is the most notable feature produced by weathering; iron oxides and silica subsequently filled these fractures, conferring a breccia-like character to the rock. The clay minerals are predominantly illitic, reflecting the mineral composition of the protolith. Smaller amounts of interstratified I/S RO type are also present, as well as scarce caolinite+chlorite that originated from the weathering of feldspar and biotite, respectively. The geochemical parameters define the weathering as incipient, in contrast to the geomorphological characteristics of Sierra Norte, which point to a long weathering history. This apparent incompatibility could be due to the probable erosion of the more weathered levels of the ancient peneplains, of which only a few relicts remain. Similar processes have been described at different sites in the Sierras Pampeanas. Reconstruction and dating of the paleosurfaces will make it possible to set time boundaries on the weathering processes studied and adjust the paleographic and paleoclimatic interpretations of this great South American region.

  10. Evaluación de la utilidad diagnóstica de la versión española del cuestionario al informador «AD8»☆

    PubMed Central

    Pardo, C. Carnero; de la Vega Cotarelo, R.; Alcalde, S. López; Aparicio, C. Martos; Carrillo, R. Vílchez; Gavilán, E. Mora; Galvin, J.E.

    2012-01-01

    Introducción El AD8 es un cuestionario al informador breve que puede ser autoaplicado y facilita la identificación de deterioro cognitivo (DC); nuestro objetivo es evaluar la utilidad diagnóstica (UD) de una versión española. Material y métodos Estudio transversal en una muestra clínica de díadas paciente/ informador, 330 sujetos con sospecha de DC o demencia (DEM) y 71 controles. Se ha evaluado la consistencia interna (α de Cronbach) y la validez (correlaciones parciales con estadio GDS, Fototest e índice funcional [IF]). La UD se ha evaluado para no DC vs DC (GDS 3–4) por medio del área bajo la curva ROC (aROC) y se ha considerado mejor punto de corte aquel que hacía máximo el índice de Youden. Resultados En la muestra, 105 no tenían DC, 99 tenían DC sin DEM y 203 DEM. La consistencia interna es alta (α 0,90, IC del 95%, 0,89–0,92), al igual que las correlaciones con GDS (r = 0,72, p < 0,001), Fototest (r = −0,61, p < 0,001) e IF (r = 0,59, p < 0,001). El aROC del AD8 es 0,90 (IC del 95%, 0,86–0,93), sin diferencia significativa con la del Fototest (aROC 0,93, IC del 95%, 0,89–0,96); el mejor punto de corte es 3/4 con sensibilidad de 0,93 (IC del 95%, 0,88–0,96), especificidad de 0,81 (IC del 95%, 0,72–0,88) y el 88,8% de las clasificaciones correctas. El uso conjunto de AD8 y Fototest mejora de forma significativa la UD de ambos (aROC 0,96, IC del 95%, 0,93–0,98, p < 0,05). Conclusiones La versión española del AD8 conserva las cualidades psicométricas y la UD de la versión original; su uso combinado con el Fototest mejora de forma significativa la UD de ambos. PMID:22652137

  11. The origin of bajaites from the San Borja Volcanic Field in Baja California Norte, Mexico

    NASA Astrophysics Data System (ADS)

    Bibbins, M.; Castillo, P.; Negrete-Aranda, R.; Canon-Tapia, E.; Alva-Valdivia, L. M.; Garcia-Amador, B. I.

    2014-12-01

    Baja California is a peninsula in western Mexico that was formed through a dynamic tectonic history of convergence, rifting and strike slip motion. At approximately 13 Ma, subduction along the northwestern coast of Mexico stopped, subsequently the Gulf of California opened and strike slip faults formed parallel to the ancient trench. After subduction ended, arc-related magmatism continued as the Baja peninsula was forming until about 2 Ma. The lavas erupting in the peninsula have variable compositions including calc-alkalic and tholeiitic arc basalts and bajaites. The term bajaite is a collective term for the high magnesian andesites and basaltic andesites in Baja California that have adakitic characteristics. Adakites, on the other hand, are arc lavas characterized by high silica content and Sr/Y and La/Yb ratios; these are generally believed to have formed through melting of subducted basaltic crust. The origin of bajaite is controversial. It has been proposed as product of melting of either subducted basaltic crust primarily because of its adakitic characteristics (Saunders et al, 1987) or metasomatized mantle wedge because of its arc lava-like geochemical features (Castillo, 2008); it has also been proposed as a mixture of differentiated and mafic arc lavas (Streck et al, 2007). The composition of bajaite is similar to that of the bulk continental crust and, thus, its true origin can shed light on the mechanism for continental growth. In this study, we use geochemical techniques to resolve some of the controversies surrounding the origin of bajaite. We analyze the petrographic, major element, trace element, and Sr-Nd-Pb isotopic compositions of bajaites from the San Borja Volcanic Field in Baja California Norte, Mexico to better constrain their petrogenetic history and origin.

  12. Adaptive Calibration of Children's Physiological Responses to Family Stress: The Utility of Evolutionary Developmental Theory--Comment on Del Giudice et al. (2012) and Sturge-Apple et al. (2012)

    ERIC Educational Resources Information Center

    Bugental, Daphne Blunt

    2012-01-01

    Children's physiological reactions to stress are presented from the broader theoretical perspective of adaptive calibration to the environment, as rooted in life history theory. Del Giudice, Hinnant, Ellis, and El-Sheikh (2012) focus on children's physiological responses to a stressful task as a consequence of their history of family stress.…

  13. 78 FR 18783 - Establishment of the R[iacute]o Grande del Norte National Monument

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ... code 3295-F3 ] TD28MR13.010 [FR Doc. 2013-07406 Filed 3-27-13; 8:45 am] Billing code 4310-10-C #0; ... predators, including the ringtail, black bear, coyote, red fox, cougar, and bobcat. While diverse...

  14. HYDROCARBON SOURCE APPORTIONMENT FOR THE 1996 PASO DEL NORTE OZONE STUDY. (R826237)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. Assessment of potential shale gas and shale oil resources of the Norte Basin, Uruguay, 2011

    USGS Publications Warehouse

    Schenk, Christopher J.; Kirschbaum, Mark A.; Charpentier, Ronald R.; Cook, Troy; Klett, Timothy R.; Gautier, Donald L.; Pollastro, Richard M.; Weaver, Jean N.; Brownfield, Michael

    2011-01-01

    Using a performance-based geological assessment methodology, the U.S. Geological Survey estimated mean volumes of 13.4 trillion cubic feet of potential technically recoverable shale gas and 0.5 billion barrels of technically recoverable shale oil resources in the Norte Basin of Uruguay.

  16. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) Registry -- ...

  17. ALS Association

    MedlinePlus

    ... ALS. Find Out How Our Mission Leading the fight to treat and cure ALS through global research ... you participate, advocate, and donate, you advance the fight to find the cure and lead us toward ...

  18. Willingness to Pay for Dog Rabies Vaccine and Registration in Ilocos Norte, Philippines (2012)

    PubMed Central

    Birhane, Meseret G.; Miranda, Mary Elizabeth G.; Dyer, Jessie L.; Blanton, Jesse D.; Recuenco, Sergio

    2016-01-01

    Background The Philippines is one of the developing countries highly affected by rabies. Dog vaccination campaigns implemented through collaborative effort between the government and NGOs have played an important role in successfully reducing the burden of disease within the country. Nevertheless, rabies vaccination of the domestic animal population requires continuous commitment not only from governments and NGOs, but also from local communities that are directly affected by such efforts. To create such long-term sustained programs, the introduction of affordable dog vaccination and registration fees is essential and has been shown to be an important strategy in Bohol, Philippines. The aim of this study, therefore, was to estimate the average amount of money that individuals were willing to pay for dog vaccination and registration in Ilocos Norte, Philippines. This study also investigated some of the determinants of individuals’ willingness to pay (WTP). Methods A cross-sectional questionnaire was administered to 300 households in 17 municipalities (out of a total of 21) selected through a multi-stage cluster survey technique. At the time of the survey, Ilocos Norte had a population of approximately 568,017 and was predominantly rural. The Contingent Valuation Method was used to elicit WTP for dog rabies vaccination and registration. A ‘bidding game’ elicitation strategy that aims to find the maximum amount of money individuals were willing to pay was also employed. Data were collected using paper-based questionnaires. Linear regression was used to examine factors influencing participants’ WTP for dog rabies vaccination and registration. Key Results On average, Ilocos Norte residents were willing to pay 69.65 Philippine Pesos (PHP) (equivalent to 1.67 USD in 2012) for dog vaccination and 29.13PHP (0.70 USD) for dog registration. Eighty-six per cent of respondents were willing to pay the stated amount to vaccinate each of their dogs, annually. This study

  19. Utilization of LANDSAT orbital imagery in the soil survey processes at Rio Grande do Norte state

    NASA Technical Reports Server (NTRS)

    Formaggio, A. R. (Principal Investigator)

    1984-01-01

    Pedologic photointerpretative criteria adapted to LANDSAT orbital imagery were used: drainage (pattern, integration degree, density and uniformity degree); relief (pattern, dissection degree and crest lines); photographic texture, photographic tonnality, and the land use (type, glebas size and intensity of use). The performance of the imagery as an auxiliar tool in the soil survey processes, at Rio Grande do Norte State was evaluated. The drainage and relief elements were easily extracted from the imagery and also ones that provided the greatest deductive possibility about pedologic boundaries. Other analyzed criteria were considered only auxiliaries, corroborating some soil limits in the evidences convergence phase. The principal pedologic dominions of the 30,000 sq km are covered by the same LANDSAT image (WRS 359/16) were delimited with good precision: (1) fluvial plains, beaches, dunes and coastal mangroves; (2) North Coast line Plateau; (3) Acu Sandstone Zone; (4) residual plateaus of the Tertiary; and (6) plains of the embasement.

  20. 3 CFR 8946 - Proclamation 8946 of March 25, 2013. Establishment of the Río Grande del Norte National Monument

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... covering the mountain's northern slopes, the diversity of both ecosystems and species allows for, and has... landscape also exhibits significant ecological diversity in these different geologic areas. From the..., and American avocets. Several species of bats make their home in the gorge, which also...

  1. [Cutaneous myiasis by Cochliomyia hominivorax (Coquerel) (Diptera Calliphoridae) in Hospital Universidad del Norte, Soledad, Atlántico].

    PubMed

    de la Ossa, Napoleón; Castro, Luis Eduardo; Visbal, Lila; Santos, Ana María; Díaz, Esther; Romero-Vivas, Claudia M E

    2009-03-01

    Human myiasis is the parasitism of human tissues by fly larvae. Diagnoses are based on clinical pattern of tissue damage and presence of insect stages. Herein, a case myiasis is described in a seven-year-old female child. She presented with fever associated with abscessed scalp lesions containing exposed larvae. Severe pediculosis was also observed. The patient was hospitalized and treated with clindamycin, gentamicin (for bacterial secondary infections) and ivermectin (treatment for lice) after which the patient showed clinical improvement and was discharged four days later. Since human myiasis can be caused by a number of different species, larvae were collected from the patient and identified as those of Cochliomyia hominivorax (Diptera: Calliphoridae). Because other cases of coinfestation of flies and lice are on record, health workers are to be alerted about the possible pediculosis-myasis risk. PMID:19753834

  2. Aquatic biology of the Redwood Creek and Mill Creek drainage basins, Redwood National Park, Humboldt and Del Norte counties, California

    USGS Publications Warehouse

    Iwatsubo, Rick T.; Averett, R.C.

    1981-01-01

    A 2-year study of the aquatic biota in the Redwood Creek and Mill Creek drainage basins of Redwood National Park indicated that the aquatic productivity is low. Densities of coliform bacteria were low except in Prairie Creek, a tributary to Redwood Creek, where a State park, county fish hatchery, grazing land, lumber mill, and scattered residential areas are potential sources of fecal coliform bacteria. Benthic invertebrate data indicated a diverse fauna which varied considerably between streams and among stream sections. Noteworthy findings include: (1) benthic invertebrates rapidly recolonized the streambed following a major storm, and (2) man-caused disruption or sedimentation of the streambed during low flow can result in drastic reductions of the benthic invertebrate community. Seven species of fish representing species typically found in northern California coastal streams were captured during the study. Nonparametric statistical tests indicate that condition factors of steelhead trout were significantly larger at sampling stations with more insolation, regardless of drainage basin land-use history. Periphyton and phytoplankton communities were diverse, variable in numbers, and dominated by diatoms. Seston concentrations were extremely variable between stations and at each station sampled. The seston is influenced seasonally by aquatic productivity at each station and amount of allochthonous material from the terrestrial ecosystem. Time-series analysis of some seston data indicated larger and sharper peak concentrations being flushed from the logged drainage basin than from the control drainage basin. (USGS)

  3. Determination of β haplotypes in patients with sickle-cell anemia in the state of Rio Grande do Norte, Brazil.

    PubMed

    Cabral, Cynthia Hatsue Kitayama; Serafim, Edvis Santos Soares; de Medeiros, Waleska Rayane Dantas Bezerra; de Medeiros Fernandes, Thales Allyrio Araújo; Kimura, Elza Miyuki; Costa, Fernando Ferreira; de Fátima Sonati, Maria; Rebecchi, Ivanise Marina Moretti; de Medeiros, Tereza Maria Dantas

    2011-07-01

    β(S) haplotypes were studied in 47 non-related patients with sickle-cell anemia from the state of Rio Grande do Norte, Brazil. Molecular analysis was conducted by PCR/RFLP using restriction endonucleases XmnI, HindIII, HincII and HinfI to analyze six polymorphic sites from the beta cluster. Twenty-seven patients (57.5%) were identified with genotype CAR/CAR, 9 (19.1%) CAR/BEN, 6 (12.8%) CAR/CAM, 1 (2.1%) BEN/BEN, 2 (4.3%) CAR/Atp, 1 (2.1%) BEN/Atp and 1 (2.1%) with genotype Atp/Atp. The greater frequency of Cameroon haplotypes compared to other Brazilian states suggests the existence of a peculiarity of African origin in the state of Rio Grande do Norte. PMID:21931513

  4. Albedo estimation using near infrared photography at Glaciar Norte of Citlaltepetl Volcano (Mexico).

    NASA Astrophysics Data System (ADS)

    Ontiveros, Guillermo; Delgado-Granados, Hugo

    2015-04-01

    In this work we show preliminary results of the application of the methodology proposed by Corripio (2004) for albedo estimation of a glacial surface using oblique photography. This analysis was performed for the Glaciar Norte of Citlaltepetl volcano (Mexico), using images obtained with a modified digital camera for capturing the portion of the near infrared spectrum starting at 950 nm and a digital elevation model with a grid of 2 m. The main goal was to obtain a picture of the spatial distribution of albedo on the glacier, in order to find out if there was any morphological evidence of the influence of the glacier energy balance. Some of the obtained results show a certain spatial distribution with comparatively higher albedo values at the lower parts of the glacier as compared with higher parts. The higher values may correspond to different metamorphism of snow/ice at different heights due to the effects of lower slope. Corripio, J. G. (2004). Snow surface albedo estimation using terrestrial photography. International journal of remote sensing, 25(24), 5705-5729.

  5. Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru

    NASA Astrophysics Data System (ADS)

    Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.

    2013-06-01

    The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The δ34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite

  6. Modeling the Crust and Upper Mantle in Northern Beata Ridge (CARIBE NORTE Project)

    NASA Astrophysics Data System (ADS)

    Núñez, Diana; Córdoba, Diego; Cotilla, Mario Octavio; Pazos, Antonio

    2016-05-01

    The complex tectonic region of NE Caribbean, where Hispaniola and Puerto Rico are located, is bordered by subduction zone with oblique convergence in the north and by incipient subduction zone associated to Muertos Trough in the south. Central Caribbean basin is characterized by the presence of a prominent topographic structure known as Beata Ridge, whose oceanic crustal thickness is unusual. The northern part of Beata Ridge is colliding with the central part of Hispaniola along a transverse NE alignment, which constitutes a morphostructural limit, thus producing the interruption of the Cibao Valley and the divergence of the rivers and basins in opposite directions. The direction of this alignment coincides with the discontinuity that could explain the extreme difference between west and east seismicity of the island. Different studies have provided information about Beata Ridge, mainly about the shallow structure from MCS data. In this work, CARIBE NORTE (2009) wide-angle seismic data are analyzed along a WNW-ESE trending line in the northern flank of Beata Ridge, providing a complete tectonic view about shallow, middle and deep structures. The results show clear tectonic differences between west and east separated by Beata Island. In the Haiti Basin area, sedimentary cover is strongly influenced by the bathymetry and its thickness decreases toward to the island. In this area, the Upper Mantle reaches 20 km deep increasing up to 24 km below the island where the sedimentary cover disappears. To the east, the three seamounts of Beata Ridge provoke the appearance of a structure completely different where sedimentary cover reaches thicknesses of 4 km between seamounts and Moho rises up to 13 km deep. This study has allowed to determine the Moho topography and to characterize seismically the first upper mantle layers along the northern Beata Ridge, which had not been possible with previous MCS data.

  7. Modeling the Crust and Upper Mantle in Northern Beata Ridge (CARIBE NORTE Project)

    NASA Astrophysics Data System (ADS)

    Núñez, Diana; Córdoba, Diego; Cotilla, Mario Octavio; Pazos, Antonio

    2015-10-01

    The complex tectonic region of NE Caribbean, where Hispaniola and Puerto Rico are located, is bordered by subduction zone with oblique convergence in the north and by incipient subduction zone associated to Muertos Trough in the south. Central Caribbean basin is characterized by the presence of a prominent topographic structure known as Beata Ridge, whose oceanic crustal thickness is unusual. The northern part of Beata Ridge is colliding with the central part of Hispaniola along a transverse NE alignment, which constitutes a morphostructural limit, thus producing the interruption of the Cibao Valley and the divergence of the rivers and basins in opposite directions. The direction of this alignment coincides with the discontinuity that could explain the extreme difference between west and east seismicity of the island. Different studies have provided information about Beata Ridge, mainly about the shallow structure from MCS data. In this work, CARIBE NORTE (2009) wide-angle seismic data are analyzed along a WNW-ESE trending line in the northern flank of Beata Ridge, providing a complete tectonic view about shallow, middle and deep structures. The results show clear tectonic differences between west and east separated by Beata Island. In the Haiti Basin area, sedimentary cover is strongly influenced by the bathymetry and its thickness decreases toward to the island. In this area, the Upper Mantle reaches 20 km deep increasing up to 24 km below the island where the sedimentary cover disappears. To the east, the three seamounts of Beata Ridge provoke the appearance of a structure completely different where sedimentary cover reaches thicknesses of 4 km between seamounts and Moho rises up to 13 km deep. This study has allowed to determine the Moho topography and to characterize seismically the first upper mantle layers along the northern Beata Ridge, which had not been possible with previous MCS data.

  8. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  9. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  10. Mapping of Glacial Motion and Surface Topography of Hielo Patagonico Norte, Chile, Using Satellite SAR L-band Interferometry Data

    NASA Technical Reports Server (NTRS)

    Rignot, Eric; Forster, Rick; Isacks, Bryan

    1996-01-01

    The first topographic and ice-motion maps of the northwestern flank of Hielo Patagonico Norte (HPN, northern Patagonia Icefield), in Chile, were produced using satellite synthetic-aperture interferometric radar data acquired by NASA's Spaceborne Imaging Radar C instrument in October 1994. The topographic map has a IO m vertical precision with a 30 m horizontal spacing, which should be sufficient to serve as a reference for monitoring future mass changes of the icefield. The ice-motion map is accurate to within 4 mm/ d (or 1/ ma). The radar-derived surface topography and ice velocity are used to estimate the ice discharge from the accumulation area of four outlet glaciers, and the calving flux and mass balance of Glaciar San Rafael. The results demonstrate the use of SAR interferometry for monitoring glaciological parameters on a spatial and temporal scale unattainable by any other means.

  11. [Maternal near misses and health inequalities: an analysis of contextual determinants in the State of Rio Grande do Norte, Brazil].

    PubMed

    Rosendo, Tatyana Maria Silva de Souza; Roncalli, Angelo Giuseppe

    2016-01-01

    The scope of this study was to identify socioeconomic contextual and health care factors in primary care associated with maternal near misses and their marker conditions. This is an ecological study that used aggregated data of 63 clusters formed by the municipalities of State of Rio Grande do Norte, Brazil, using the Skater method of area regionalization, as the unit of analysis. The ratio of maternal near misses and their marker conditions were obtained from the Hospital Information System of the Brazilian Unified Health System. In multiple linear regression analysis, there was a significant association between maternal near misses and variables of poverty and poor primary health care. Hypertensive disorders were also associated with poverty and poor primary care and the occurrence of hemorrhaging was associated with infant mortality. It was observed that the occurrence of maternal near misses is linked to unfavorable socioeconomic conditions and poor quality health care that are a reflection of public policies that accentuate health inequalities. PMID:26816176

  12. Animal-based folk remedies sold in public markets in Crato and Juazeiro do Norte, Ceará, Brazil

    PubMed Central

    Ferreira, Felipe S; Brito, amuel V; Ribeiro, Samuel C; Saraiva, Antônio AF; Almeida, Waltécio O; Alves, Rômulo RN

    2009-01-01

    Background Human communities consistently develop a detailed knowledge of the therapeutical and medicinal properties of the local flora and fauna, and these folk remedies often substitute medicines produced by the pharmaceutical industry. Animals (and their derived products) are essential ingredients in the preparation of many traditional remedies. The present work prepared an inventory of the animals sold in public markets in the cities of Crato and Juazeiro do Norte, Ceará State, Brazil. Methods Information was obtained through the use of semi-structured questionnaires in interviews held with 27 merchants of medicinal animals (18 in the municipality of Juazeiro do Norte [11 men and 7 women] and 9 people in the municipality of Crato [6 men and 3 women]). We calculated the Informant Consensus Factor (ICF) to determine the consensus over which species are effective for particular ailments, as well as the species Use Value (UV) to determine the extent of utilization of each species. Results A total of 31 animal species, distributed among 21 families were identified as being used medicinally. The taxa most represented were: insects (8 species), mammals (7), fish (5), reptiles (5) and birds (4). The animals sold in these markets are used to treat a total of 24 ailments, with rheumatism, asthma, and inflammations having the largest numbers of citations. Three species not previously reported as having medicinal use were encountered: Leporinus steindachneri (utilized for treating cholesterol problems), Gryllus assimilis (utilized in treating urinary infections), and Phrynops tuberosus (used to treat asthma, rheumatism and bruises). Conclusion The composition of the local fauna, the popular culture, and commercial considerations are factors that maintain and drive the market for therapeutic animal products – and the lack of monitoring and regulation of this commerce is worrisome from a conservationist perspective. A detailed knowledge of the fauna utilized in

  13. Ground-water resources of the Acu Valley, Rio Grande Norte, Brazil

    USGS Publications Warehouse

    Rodis, Harry G.; de Castro Araujo, Jonas Maria.

    1968-01-01

    The Acu Valley is the lower part of the Rio Piranhas valley in the northwestern part of the State of Rio Grande do Norte, Brazil. It begins where the Rio Piranhas leaves the crystalline Precambrian rocks to flow across the outcrop of sedimentary rocks. The area considered in this report extends northward for about 45 kilometers; it is terminated arbitrarily where encroachment by sea water has contaminated the aquifer and imparted a disagreeable saline taste to the water in it. The boundary was not determined in the field, however, for lack of special equipment. Part of the extensive uplands on either side of the valley are included. This makes the total area approximately 2,500 square kilometers. The largest town, Acu, had a population of about 8,000 in 1960. The area is considered to be part of the Drought Polygon of northeast Brazil because the precipitation, although averaging 448 millimeters annually at Acu, varies widely from year to year and often is deficient for many months. The precipitation has been supplemented by use of irrigation wells, but irrigated agriculture is not yet far advanced, and the quantities of water used in irrigation are small. Geologically, the area consists of basement crystalline rocks (Precambrian), a wedge of sedimentary rocks thickening northward (Cretaceous), and alluvial sediments constituting a narrow band in the bottom of the valley (Alluvium and terrace deposits). The crystalline rocks contain water mainly in fractures and, in general, are impermeable. The sedimentary rocks of Cretaceous age comprise two units: a thick but fine-grained sandstone grading upward into siltstone and shale (Acu Sandstone), and limestone and dolomite with an included shale zone (Jandaira Limestone). The sandstone especially and the limestone to a lesser degree are ground-water reservoirs of large capacity. The limestone has been tapped at several places, but the sandstone and its contained water are practically untested and, hence, imperfectly

  14. Determination of βS haplotypes in patients with sickle-cell anemia in the state of Rio Grande do Norte, Brazil

    PubMed Central

    Cabral, Cynthia Hatsue Kitayama; Serafim, Édvis Santos Soares; de Medeiros, Waleska Rayane Dantas Bezerra; de Medeiros Fernandes, Thales Allyrio Araújo; Kimura, Elza Miyuki; Costa, Fernando Ferreira; de Fátima Sonati, Maria; Rebecchi, Ivanise Marina Moretti; de Medeiros, Tereza Maria Dantas

    2011-01-01

    βS haplotypes were studied in 47 non-related patients with sickle-cell anemia from the state of Rio Grande do Norte, Brazil. Molecular analysis was conducted by PCR/RFLP using restriction endonucleases XmnI, HindIII, HincII and HinfI to analyze six polymorphic sites from the beta cluster. Twenty-seven patients (57.5%) were identified with genotype CAR/CAR, 9 (19.1%) CAR/BEN, 6 (12.8%) CAR/CAM, 1 (2.1%) BEN/BEN, 2 (4.3%) CAR/Atp, 1 (2.1%) BEN/Atp and 1 (2.1%) with genotype Atp/Atp. The greater frequency of Cameroon haplotypes compared to other Brazilian states suggests the existence of a peculiarity of African origin in the state of Rio Grande do Norte. PMID:21931513

  15. Consanguinity and founder effect for Gaucher disease mutation G377S in a population from Tabuleiro do Norte, Northeastern Brazil.

    PubMed

    Chaves, R G; Pereira, L da Veiga; de Araújo, F T; Rozenberg, R; Carvalho, M D F; Coelho, J C; Michelin-Tirelli, K; Chaves, M de Freitas; Cavalcanti, G B

    2015-10-01

    Gaucher's disease (GD) is caused by a β-glucocerebrosidase deficiency, leading to the accumulation of glucocerebroside in the reticuloendothelial system. The prevalence of GD in Tabuleiro do Norte (TN) (1:4000) is the highest in Brazil. The purpose of this study was to present evidence of consanguinity and founder effect for the G377S mutation (c.1246G>A) among GD patients in TN based on enzyme, molecular and genealogical studies. Between March 2009 and December 2010, 131 subjects at risk for GD (GC in dried blood ≤2.19 nmol/h/ml) and 5 confirmed GD patients from the same community were submitted for molecular analysis to characterize the genetic profile of the population. Based on the enzymatic and molecular analysis, the subjects were classified into three categories: affected (n = 5), carrier (n = 20) and non-carrier (n = 111). All carriers were (G377S/wt). Affected subjects were homozygous (G377S/G377S). The identification of a single mutation in carriers and homozygotes from different generations, the history of the community and the genealogy study suggest that the high prevalence of GD in this population may be due to a combination of consanguinity and founder effect for the G377S mutation. PMID:25287185

  16. Support Services for Exceptional Students: Butte, Del Norte, Glenn, Humboldt, Lake, Lassen, Mendocino, Modoc, Plumas, Shasta, Siskiyou, Tehama, and Trinity Counties.

    ERIC Educational Resources Information Center

    Hampel, Angelica; And Others

    Intended for use by vocational administrators responsible for mainstreaming handicapped students into vocational education classes, the resource guide lists and describes governmental and private agencies that provide vocational programs and support services for the handicapped on a local and statewide basis in the California counties of Butte,…

  17. High resolution sup 40 Ar/ sup 39 Ar chronostratigraphy of the Late Cretaceous El Gallo Formation, Baja California del Norte, Mexico

    SciTech Connect

    Fulford, M.M.; Busby-Spera, C. ); Renne, P.R.

    1991-03-01

    Laser probe {sup 40}Ar/{sup 39}Ar analyses of individual sanidine grains from four tuffs in the alluvial Late Cretaceous (Campanian) El Gallo Formation yield statistically distinct mean dates ranging from 74.87 {plus minus} 0.05 Ma to 73.59 {plus minus} 0.09 Ma. The exceptional precision of these dates permits calculation of statistically significant sediment accumulation rates that are much higher than passive sediment loading would cause, implying rapid tectonically induced subsidence. The dates bracket tightly the age of important dinosaur and mammalian faunas previously reported from the El Gallo Formation. The dates support an age less than 73 Ma for the Campanian/Maastrichtian stage boundary, younger than indicated by several currently used time scales. Further application of the single grain {sup 40}Ar/{sup 39}Ar technique may be expected to greatly benefit stratigraphic studies of Mesozoic sedimentary basins and contribute to calibration of biostratigraphic and magnetostratigraphic time scales.

  18. Nutrition Knowledge Predicts Eating Behavior of All Food Groups "except" Fruits and Vegetables among Adults in the Paso del Norte Region: Que Sabrosa Vida

    ERIC Educational Resources Information Center

    Sharma, Shreela V.; Gernand, Alison D.; Day, R. Sue

    2008-01-01

    Objective: To examine the association between nutrition knowledge and eating behavior in a predominantly Mexican American population on the Texas-Mexico border. Design: Cross-sectional using data from the baseline survey of the Que Sabrosa Vida community nutrition initiative. Setting: El Paso and surrounding counties in Texas. Participants: Data…

  19. Redwood National Park studies; data release number 2, Redwood Creek, Humboldt County, and Mill Creek, Del Norte County, California, April 11, 1974-September 30, 1975

    USGS Publications Warehouse

    Iwatsubo, Rick T.; Nolan, K.M.; Harden, D.R.; Glysson, G.D.

    1976-01-01

    An interdisciplinary study has been undertaken in Redwood National Park, Calif., to describe parts of the ecosystems and recent changes in the intensity of erosion and sedimentation, define processes that may alter the natural ecosystems, and assess the impact of recent road construction and timber harvest. This report is the second of a series that will present data collected in this study. Stream-discharge and water-quality data were collected at 53 sampling stations in the Redwood Creek and Mill Creek drainage basins. Measurements included the following variables: Stream stage and discharge; turbidity; sediment; onsite water-quality determinations of temperature, pH , total alkalinity, specific conductance, and dissolved-oxxygen concentration; chemical analyses of water samples for major dissolved solids, selected trace elements, nitrogen, phosphorus, and organic carbon; chemical analyses of bottom sediment for organic carbon and pesticides; bacteria; benthic invertebrates; fish; periphyton; phytoplankton; and seston. Additional data include changes in geometry at 10 stream-channel cross sections along Mill Creek and the distribution of erosional landforms in the Mill Creek drainage basin; quantity and chemical composition of rainwater; and the intragravel-streambed condition at selected stations in the Redwood Creek drainage basin. (Woodard-USGS)

  20. Se evitaron casi 800 000 muertes por descenso del tabaquismo

    Cancer.gov

    Programas y estrategias de control del tabaco del siglo XX fueron responsables de la prevención de más de 795 000 muertes por cáncer de pulmón en Estados Unidos de 1975 al 2000. Si todo el tabaquismo en este país hubiera cesado después de la publicación d

  1. Relevamiento total del hemisferio sur celeste en la frecuencia de 1420 MHz

    NASA Astrophysics Data System (ADS)

    Bava, J. A.; Colomb, F. R.; Hurrel, E.; Larrarte, J. J.; Sanz, A. J.; Testori, J. C.; Reich, P.; Reich, W.; Wielebinski, R.

    En el presente artículo se describe el relevamiento del cielo en el Hemisferio Sur Celeste en la frecuencia de 1420 MHz para declinaciones δ<= -19o realizado con la Antena II de 30 metros de diámetro del IAR. Este relevamiento posee igual sensibilidad (3xr.m.s=50 mK) que el realizado en el Hemisferio Norte con el radiotelescopio de 25 metros de Stockert de la Universidad de Bonn, operado por el Max-Planck Institute für Radioastronomie ( Reich W., 1982, A&ASS 48, 219; Reich P. and Reich W., 1986, A&ASS 63, 205). Con los datos obtenidos por ambos radiotelescopios se posee una base de datos de todo el cielo en esta frecuencia. En esta publicación presentamos los detalles del sistema receptor, técnicas de observación y reducción de datos, calibración y discusión de los errores en los resultados.

  2. The surface energy balance of the Guanaco and Toro 1 glaciers in the Norte Chico region, Chile

    NASA Astrophysics Data System (ADS)

    MacDonell, Shelley; Mölg, Thomas; Nicholson, Lindsey; Kinnard, Christophe

    2010-05-01

    The ablation of the cold, arid, high-altitude glaciers of the Norte Chico region in Chile remains poorly constrained at present. The development of ablation features such as penitentes indicate that sublimation processes are prevalent, but equally the presence of ponds and cryoconite holes in the near-surface ice indicate that melt can also play a role in the ablation of these glaciers. In this paper we used meteorological data collected from the surfaces of the Guanaco and Toro 1 glaciers between October 2008 and July 2009 to determine the conditions that control the energy balance and the resulting mass loss by surface ablation. We investigate the diurnal and seasonal energy exchanges on each glacier to evaluate whether the processes on each are equivalent, before calculating the ratio of sublimation to melt on each. We found that melt was more important on Guanaco Glacier than on Toro 1 Glacier, and that the seasonal peak of ablation occurred on Guanaco Glacier between December and late January, whereas the ablation peak on Toro 1 Glacier between February and March. This ablation offset is probably related to differences in the terrain surrounding each climate station, such that on Guanaco Glacier, the surrounding terrain is planar, whereas on Toro 1 Glacier, whilst the immediate area around the climate station was free of penitentes for much of the modelled time, penitentes grew around the station, changing the roughness length, and hence the importance of sublimation. This study showed that the development of penitentes during an ablation season changes the importance of energy balance terms, and hence the types of ablation experienced on a glacier. In future we hope to be able to model ablation from penitente-covered regions more accurately, and to develop a distributed energy balance model for use on glaciers where penitentes exist.

  3. [Child health in poor areas: findings from a population-based study in Caracol, Piauí, and Garrafão do Norte, Pará, Brazil].

    PubMed

    Cesar, Juraci A; Chrestani, Maria Aurora D; Fantinel, Everton J; Gonçalves, Tatiane S; Neumann, Nelson A

    2009-04-01

    The aim of this study was to evaluate child health indicators in the municipalities (counties) of Caracol, Piauí State, and Garrafão do Norte, Pará State, Brazil. Through household visits using systematic sampling, previously trained interviewers applied a standard questionnaire to mothers of under-five children, investigating socioeconomic status, housing and environmental sanitation, demographic characteristics, disease patterns, and prenatal and childbirth care. The analysis used the t-test and chi-square test to compare indicators between the two municipalities. Of the 1,728 children studied, 60% were from families with incomes less than one monthly minimum wage (approximately U$200), 41% had no type of sewage treatment or disposal, 10% of mothers reported zero prenatal visits, 30% of the children were born in the same municipality, and 30% had been taken to a pediatric consultation in the previous 3 months; 20% had a height-for-age deficit > 2 standard deviations. All target indicators were deficient in both the municipalities (especially in Garrafão do Norte). Expanding health care supply and improving housing and sanitation conditions are priorities in both municipalities. PMID:19347207

  4. ALS - The cost cutter

    NASA Astrophysics Data System (ADS)

    Colucci, Frank

    1987-10-01

    The Advanced Launch System (ALS) development program will avail itself of existing technologies in the short term in order to produce an interim 'core' vehicle that may be operational by 1993; the full, booster-incorporating system objective will then be achieved in 1998. This programmatic 'decoupling' of booster and core vehicle development efforts will separate their funding peaks. The ALS program will cut costs by colocating manufacturing and launch facilities, using Al-Li alloys in booster primary structures, and aggressively applying 'paperless' CIM. The ALS launch vehicle configuration will be primarily determined by both payload requirements and flight frequency.

  5. Preguntas y respuestas acerca del Estudio del

    Cancer.gov

    El Estudio del Tamoxifeno y Raloxifeno (STAR, por sus siglas en ingls) es un estudio clnico (un estudio de investigacin conducido con voluntarios) diseado para ver cómo el medicamento raloxifeno (Evista) se compara con el medicamento tamoxifeno (Nolvadex)

  6. Cosmogenic Radionuclides in the Campo Del Cielo Iron Meteorite

    NASA Technical Reports Server (NTRS)

    Liberman, R. G.; FernandezNiello, J. O.; Reedy, R. C.; Fifield, L. K.; diTada, M. L.

    2001-01-01

    Cosmogenic Be-10, Al-26, Cl-36, Ca-41, and Ni-59 were measured in the Campo del Cielo iron meteorite. Our results led us to conclude that the pre-atmospheric radius might have been approximately 2 m. Comparisons with other big bodies are also presented. Additional information is contained in the original extended abstract.

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

    NASA Astrophysics Data System (ADS)

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

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

  8. Al-Anon/Alateen

    MedlinePlus

    Find an Al-Anon meeting Español | Français 2018 Int'l Convention Home About Group Meetings What If I'm not ready ... a meeting? What can I expect at an Al-Anon meeting? What was my first meeting like? ...

  9. Aparición del cometa Hale - BOPP C / 1995-01

    NASA Astrophysics Data System (ADS)

    Arquiola, A.

    El Cometa Hale - Bopp fue observado a partir de la 10ma. magnitud con el telescopio de 300mm de abertura a f/6.5. En esas primeras observaciones desde luego no hubo mucho detalle. A su vez las posiciones del cometa para nuestro hemisferio no fueron favorables, solamente asomó por el horizonte N.O. para nuestra latitud cuando se alejaba de la Tierra. Se registró la observación visualmente con binoculares 10 x 50, y fotográficamente con un Telezoom de 210mm a f/4,5 con película 400 ASA color. Todas las imágenes fueron procesadas y digitalizadas a fin de obtener las diferentes escalas de brillo. El aspecto que presentó para nuestra posición geográfica fue discreta ya que tuvo su máximo brillo cuando era visible desde el hemisferio norte. Presentó la clásica cola de polvo curva, y con su aspecto casi estelar, destacándose entre la luminosidad del crepúsculo. Instrumentos Utilizados: Telezoom de 210mm a f/4.5, Telescopio refractor de 80mm a f/15, Binocular 10 x 50

  10. Il problema del litio.

    NASA Astrophysics Data System (ADS)

    D'Antona, F.

    1995-03-01

    Contents: 1. Introduzione. 2. La nucleosintesi del Big Bang. 3. Il litio nelle stelle di popolazione II. 4. I modelli stellari standard. 5. Il litio negli ammassi aperti. 6. Meccanismi di distruzione "non standard". 7. I modelli non-standard applicati alla popolazione II. 8. L'evoluzione Galattica del litio. 9. Quali stelle producono litio? 10. Il litio come elemento chiave per dare un nome agli oggetti stellari più minuscoli. 11. Conclusioni.

  11. Espectroscopia del Cometa Halley

    NASA Astrophysics Data System (ADS)

    Naranjo, O.; Fuenmayor, F.; Ferrin, L.; Bulka, P.; Mendoza, C.

    1987-05-01

    Se reportan observaciones espectroscópicas del cometa Halley. Los espectros fueron tomados usando el espectrógrafo del telescopio reflector de 1 metro del Observatorio Nacional de Venezuela. Se utilizó óptica azul, con una red de difracción de 600 lineas/min, obteniéndose una dispersión de 74.2 A/mm y una resolución de 2.5 A, en el rango espectral de 3500 a 6500 A. Seis placas fueron tomadas con emulsión IIa-O y dos con IIa-D. Los tiempos de exposición fueron entre 10 y 150 minutos. El cometa se encontraba entre 0.70 y 1.04 UA del Sol, y entre 1.28 y 0.73 UA de la Tierra. Las emisiones más prominentes en el espectro, son las del CN, C2, y C3. Otras emisiones detectadas corresponden a CH, NH2 y Na. Los espectros muestran un fuerte continuo, indicando un contenido significativo de polvo. Se detectó mayor intensidad del contínuo, en la dirección anti solar, lo cual es evidencia de la cola de polvo.

  12. [Environmental factors in ALS].

    PubMed

    Juntas-Morales, Raul; Pageot, Nicolas; Corcia, Philippe; Camu, William

    2014-05-01

    ALS is likely to be a disorder of multifactorial origin. Among all the factors that may increase the risk of ALS, environmental ones are being studied for many years, but in the recent years, several advances have pointed to a new interest in their potential involvement in the disease process, especially for the cyanotoxin BMAA. Food containing BMAA has been found on Guam, a well-known focus of ALS/parkinsonism/dementia and high levels of BMAA have been identified into the brain of these patients. The BMAA cyanotoxin is potentially ubiquitous and have also been found into the food of patients who died from ALS both in Europe and USA. BMAA can be wrongly integrated into the protein structure during mRNA traduction, competing with serine. This may induce abnormal protein folding and a subsequent cell death. Heavy metals, such as lead or mercury may be directly toxic for neuronal cells. Several works have suggested an increased risk of ALS in individuals chronically exposed to these metals. Exposure to pesticides has been suggested to be linked to an increased risk of developing ALS. The mechanism of their toxicity is likely to be mediated by paraoxonases. These proteins are in charge of detoxifying the organism from toxins, and particularly organophosphates. To date, there are insufficient scientific data to suggest that exposure to electromagnetic fields may increase the risk of having ALS. We are particularly missing longitudinal cohorts to demonstrate that risk. PMID:24703731

  13. Evidence for maize (Zea mays) in the Late Archaic (3000-1800 B.C.) in the Norte Chico region of Peru.

    PubMed

    Haas, Jonathan; Creamer, Winifred; Huamán Mesía, Luis; Goldstein, David; Reinhard, Karl; Rodríguez, Cindy Vergel

    2013-03-26

    For more than 40 y, there has been an active discussion over the presence and economic importance of maize (Zea mays) during the Late Archaic period (3000-1800 B.C.) in ancient Peru. The evidence for Late Archaic maize has been limited, leading to the interpretation that it was present but used primarily for ceremonial purposes. Archaeological testing at a number of sites in the Norte Chico region of the north central coast provides a broad range of empirical data on the production, processing, and consumption of maize. New data drawn from coprolites, pollen records, and stone tool residues, combined with 126 radiocarbon dates, demonstrate that maize was widely grown, intensively processed, and constituted a primary component of the diet throughout the period from 3000 to 1800 B.C. PMID:23440194

  14. [The meaning of health in sexual relations according to women treated under the Unified National Health System in Natal, Rio Grande do Norte State, Brazil].

    PubMed

    da Cunha, Magnus Kelly Moura; Spyrides, Maria Helena Constantino; de Sousa, Maria Bernardete Cordeiro

    2011-06-01

    The aim of this article is to discuss the social representations of "health in sexual relations" as reported by women treated under the Unified National Health System (SUS) in Natal, Rio Grande do Norte, Brazil. A total of 150 women were tested using the free word recall test, with "health in sexual relations" as the stimulus. Women were also asked about their sources of information on the subject. The results were obtained with content analysis and the EVOC software. We identified three representational dimensions: prevention, relationship with the partner, and quality of life. The central nucleus of social representation consisted of the elements "prevention" and "condoms". Likely sources for representation were television, health services, and dialogue with family members and partners. Representations were composed of concepts related to prevention, a good partner relationship, and overall well-being. The results illustrate the need to expand women's sexual health aspects that are considered relevant by the health system. PMID:21710007

  15. Evidence for maize (Zea mays) in the Late Archaic (3000–1800 B.C.) in the Norte Chico region of Peru

    PubMed Central

    Haas, Jonathan; Creamer, Winifred; Huamán Mesía, Luis; Goldstein, David; Reinhard, Karl; Rodríguez, Cindy Vergel

    2013-01-01

    For more than 40 y, there has been an active discussion over the presence and economic importance of maize (Zea mays) during the Late Archaic period (3000–1800 B.C.) in ancient Peru. The evidence for Late Archaic maize has been limited, leading to the interpretation that it was present but used primarily for ceremonial purposes. Archaeological testing at a number of sites in the Norte Chico region of the north central coast provides a broad range of empirical data on the production, processing, and consumption of maize. New data drawn from coprolites, pollen records, and stone tool residues, combined with 126 radiocarbon dates, demonstrate that maize was widely grown, intensively processed, and constituted a primary component of the diet throughout the period from 3000 to 1800 B.C. PMID:23440194

  16. All About ALS

    MedlinePlus

    ... External link, please review our exit disclaimer . Subscribe All About ALS Understanding a Devastating Disorder In the ... a coffee pot, or button a shirt. Eventually, all muscles under voluntary control are affected, and people ...

  17. Amyotrophic Lateral Sclerosis (ALS)

    MedlinePlus

    ... Pictures of ALS Mutant Proteins Support Two Major Theories About How the Disease is Caused May 2003 ... All NINDS-prepared information is in the public domain and may be freely copied. Credit to the ...

  18. Genetic Testing for ALS

    MedlinePlus

    ... Involved Donate Familial Amyotrophic Lateral Sclerosis (FALS) and Genetic Testing By Deborah Hartzfeld, MS, CGC, Certified Genetic ... guarantee a person will develop symptoms of ALS. Genetic Counseling If there is more than one person ...

  19. ALS synchrotron radiation shielding

    SciTech Connect

    Donahue, R.J.

    1995-10-01

    This note discusses the assumptions and results of synchrotron radiation shielding estimates for ALS bend magnet and wiggler beamlines. Estimates of gas bremsstrahlung production are not included and are dealt with elsewhere.

  20. What Is ALS?

    MedlinePlus

    ... scarring or hardening ("sclerosis") in the region. Motor neurons reach from the brain to the spinal cord ... the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise. When ...

  1. Reconstructing the annual mass balance of the Echaurren Norte glacier (Central Andes, 33.5° S) using local and regional hydroclimatic data

    NASA Astrophysics Data System (ADS)

    Masiokas, Mariano H.; Christie, Duncan A.; Le Quesne, Carlos; Pitte, Pierre; Ruiz, Lucas; Villalba, Ricardo; Luckman, Brian H.; Berthier, Etienne; Nussbaumer, Samuel U.; González-Reyes, Álvaro; McPhee, James; Barcaza, Gonzalo

    2016-04-01

    Despite the great number and variety of glaciers in southern South America, in situ glacier mass-balance records are extremely scarce and glacier-climate relationships are still poorly understood in this region. Here we use the longest (> 35 years) and most complete in situ mass-balance record, available for the Echaurren Norte glacier (ECH) in the Andes at ˜ 33.5° S, to develop a minimal glacier surface mass-balance model that relies on nearby monthly precipitation and air temperature data as forcing. This basic model is able to explain 78 % of the variance in the annual glacier mass-balance record over the 1978-2013 calibration period. An attribution assessment identified precipitation variability as the dominant forcing modulating annual mass balances at ECH, with temperature variations likely playing a secondary role. A regionally averaged series of mean annual streamflow records from both sides of the Andes between ˜ 30 and 37° S is then used to estimate, through simple linear regression, this glacier's annual mass-balance variations since 1909. The reconstruction model captures 68 % of the observed glacier mass-balance variability and shows three periods of sustained positive mass balances embedded in an overall negative trend over the past 105 years. The three periods of sustained positive mass balances (centered in the 1920s-1930s, in the 1980s and in the first decade of the 21st century) coincide with several documented glacier advances in this region. Similar trends observed in other shorter glacier mass-balance series suggest that the Echaurren Norte glacier reconstruction is representative of larger-scale conditions and could be useful for more detailed glaciological, hydrological and climatological assessments in this portion of the Andes.

  2. Rapidly solidified NiAl and FeAl

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Crimp, M. A.

    1984-01-01

    Melt spinning was used to produce rapidly solidified ribbons of the B2 intermetallics NiAl and FeAl. Both Fe-40Al and Fe-45Al possessed some bend ductility in the as spun condition. The bend ductility of Fe-40Al, Fe-45Al, and equiatomic NiAl increased with subsequent heat treatment. Heat treatment at approximately 0.85 T (sub m) resulted in significant grain growth in equiatomic FeAl and in all the NiAl compositions. Low bend ductility in both FeAl and NiAl generally coincided with intergranular failure, while increased bend ductility was characterized by increasing amounts of transgranular cleavage fracture.

  3. Modulus measurements in ordered Co-Al, Fe-Al, and Ni-Al alloys

    NASA Technical Reports Server (NTRS)

    Harmouche, M. R.; Wolfenden, A.

    1985-01-01

    The composition and/or temperature dependence of the dynamic Young's modulus for the ordered B2 Co-Al, Fe-Al, and Ni-Al aluminides has been investigated using the piezoelectric ultrasonic composite oscillator technique (PUCOT). The modulus has been measured in the composition interval 48.49 to 52.58 at. pct Co, 50.87 to 60.2 at. pct Fe, and 49.22 to 55.95 at. pct Ni for Co-Al, Fe-Al, and Ni-Al, respectively. The measured values for Co-Al are in the temperature interval 300 to 1300 K, while those for the other systems are for ambient temperature only. The data points show that Co-Al is stiffer than Fe-Al, which is stiffer than Ni-Al. The data points for Fe-Al and Ni-Al are slightly higher than those reported in the literature.

  4. Estudio del sistema simbiótico AR Pavonis

    NASA Astrophysics Data System (ADS)

    Quiroga, C.; Brandi, E.; Ferrer, O.; García, L.; Barbá, R.

    Se presenta un estudio espectroscópico y polarimétrico de la binaria eclipsante AR Pavonis a partir de observaciones obtenidas con el telescopio de 2.15 m. del CASLEO (San Juan). El estudio de la naturaleza del sistema se realizó a través del análisis de algunos espectros reunidos entre los años 1990 y 1995 y de datos polarimétricos correspondientes al intervalo 1995 y 1997. El análisis espectroscópico indica que AR Pav está compuesta por una gigante roja M3.7 y una componente caliente compacta, con una temperatura mayor a 90000 K y una luminosidad del orden de 500Lsolar. A lo largo del período orbital, las variaciones observadas en flujo y en velocidades radiales, reflejan que las emisiones permitidas se forman en una región que rodea la componente caliente. El estudio de la polarización lineal de AR Pav indica que además de una componente interestelar, existe una componente intrínseca del sistema que varía temporalmente y con la longitud de onda de la luz polarizada. El distinto comportamiento del grado de polarización y del ángulo de posición observado en fases diferentes, sugiere que distintos mecanismos pueden estar actuando, dependiendo de la región de scattering observado a lo largo de la línea de la visual.

  5. Al Shanker Remembers.

    ERIC Educational Resources Information Center

    American Educator, 2000

    2000-01-01

    In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

  6. ALS renewal moves forward

    NASA Astrophysics Data System (ADS)

    Falcone, R. W.; Feinberg, B.; Hussain, Z.; Kirz, J.; Krebs, G. F.; Padmore, H. A.; Robin, D. S.; Robinson, A. L.

    2007-11-01

    As the result of an extensive long-term planning process involving all its stakeholders—management, staff, and users—the ALS has seen its future and is aggressively moving ahead to implement its vision for keeping the facility at the cutting edge for the next 2-3 decades. The evolving strategic plan now in place aims to renew the ALS so it can address a new generation of fundamental questions about size dependent and dimensional-confinement phenomena at the nanoscale; correlation and complexity in physical, biological, and environmental systems; and temporal evolution, assembly, dynamics and ultrafast phenomena. The renewal spans three areas: (1) increased staffing at beamlines to support the growing user community and safety professionals to keep an increasingly complex facility hazard free; (2) implementing advances in accelerator, insertion device, beamline, and detector technology that will make it possible for ALS users to address emerging grand scientific and technological challenges with incisive world-class tools; and (3) construction of a user support building and guest housing that will increase the safety and user friendliness of the ALS by providing users office, meeting, experiment staging, and laboratory space for their work and on-site accommodations at reasonable rates.

  7. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Fosetyl - al ; CASRN 39148 - 24 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  8. TBK1 is associated with ALS and ALS-FTD in Sardinian patients.

    PubMed

    Borghero, Giuseppe; Pugliatti, Maura; Marrosu, Francesco; Marrosu, Maria Giovanna; Murru, Maria Rita; Floris, Gianluca; Cannas, Antonino; Occhineri, Patrizia; Cau, Tea B; Loi, Daniela; Ticca, Anna; Traccis, Sebastiano; Manera, Umberto; Canosa, Antonio; Moglia, Cristina; Calvo, Andrea; Barberis, Marco; Brunetti, Maura; Gibbs, J Raphael; Renton, Alan E; Errichiello, Edoardo; Zoledziewska, Magdalena; Mulas, Antonella; Qian, Yong; Din, Jun; Pliner, Hannah A; Traynor, Bryan J; Chiò, Adriano

    2016-07-01

    Recently, mutations in the TANK-binding kinase 1 (TBK1) gene were identified as a cause for amyotrophic lateral sclerosis (ALS) with or without comorbid frontotemporal dementia. We have assessed the frequency and clinical characteristics of TBK1 mutations in a cohort of ALS patients of Sardinian ancestry. Whole-exome sequencing was performed on Hiseq2000 platform (Illumina). Genome analysis Toolkit was used to align and to code variants according to Human Genome (UCSC hg19). Mutation was confirmed with Sanger sequence. In our screening of 186 Sardinian ALS cases, we found 3 (1.6%) patients carrying 3 distinct novel genetic variants: a nonsynonymous SNV c.1150C>T leading to a p.Arg384Thr change in exon 9; a nonsynonymous SNV c.1331G>A causes a p.Arg444Gln change in exon 11; and a frameshift deletion c.2070delG (p.Met690fs) at the exon 20 of the gene leading to a stop at 693 codon. The latter patients also carried missense mutation c.98C>T of the SQSTM1 gene causing a substitution of an arginine with a valine at the position 33 (p.Arg33Val). All variants were found to be deleterious according to in silico predictions. All cases were apparently sporadic and one of them showed frontotemporal dementia associated to ALS. These mutations were not found in 2 cohorts of 6780 ethnic-matched controls. We have found that TBK1 mutations account for 1.6% of Sardinian ALS cases. Our data support the notion that TBK1 is a novel ALS gene, providing important evidence complementary to the first descriptions. PMID:27156075

  9. Defining the defect in F508 del CFTR: a soluble problem?

    PubMed

    Deber, Charles M; Cheung, Joanne C; Rath, Arianna

    2008-01-01

    Previously reported crystal structures of CFTR F508 del-NBD1 were determined in the presence of solubilizing mutations. In this issue of Chemistry & Biology, Pissarra et al. (2008) show that partial rescue of the trafficking and gating defects of full-length CFTR occurs in vivo upon recapitulation of the solubilizing F494N/Q637R or F428S/F494N/Q637R substitutions in cis with F508 del. PMID:18215767

  10. ALS Project Management Manual

    SciTech Connect

    Krupnick, Jim; Harkins, Joe

    2000-05-01

    This manual has been prepared to help establish a consistent baseline of management practices across all ALS projects. It describes the initial process of planning a project, with a specific focus on the production of a formal project plan. We feel that the primary weakness in ALS project management efforts to date stems from a failure to appreciate the importance of ''up-front'' project planning. In this document, we present a guide (with examples) to preparing the documents necessary to properly plan, monitor, and control a project's activities. While following the manual will certainly not guarantee good project management, failure to address the issues we raise will dramatically reduce the chance of success. Here we define success as meeting the technical goals on schedule and within the prescribed budget.

  11. ALS insertion devices

    SciTech Connect

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1990-11-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs.

  12. Ausbildung als zentrale Aufgabe

    NASA Astrophysics Data System (ADS)

    Krämer, Walter; Schmerbach, Sibylle

    Anders als Lesen und Schreiben zählen Grundkenntnisse in Statistik heute noch nicht zu den Voraussetzungen einer sinnvollen Teilhabe am Sozialgeschehen. Und auch in der akademischen Statistik-Ausbildung gibt es noch einiges zu tun. Das vorliegende Kapitel zeichnet die Geschichte dieser akademischen Ausbildung an deutschen Universitäten nach dem zweiten Weltkrieg nach, stellt aktuelle Defizite vor und weist auf mögliche Verbesserungen hin.

  13. Nevado del Huila, Columbia

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Nevado del Huila Volcano in Colombia is actually a volcanic chain running north to south, capped by a glacier. With peaks ranging in height from 2,600 to 5,780 meters (8,530 to 18,960 feet), Nevado del Huila is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and volcanic rocks. Its first recorded eruption occurred in the mid-sixteenth century. The long-dormant volcano erupted again in mid-April 2007. A few months before the eruption, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of Nevado del Huila, on February 23, 2007. In this image, the bright white area just east of the central summit is ice. Immediately west of the summit are bare rocks, appearing as blue-gray. West of those rocks, white reappears, but this patch of white results from clouds hovering in the nearby valley. In the east, the colors turn to brown (indicating bare rock) and bright green (indicating vegetation). ASTER photographed Nevado del Huila near the end of a long phase of quietude. On April 17, 2007, local authorities recorded seismic activity associated with rock fracturing on the volcano's central summit, according to the ReliefWeb Website. Activity intensified the following day with an eruption and mudflows, forcing thousands of nearby residents to evacuate. As the Associated Press reported, the eruption caused avalanches and floods that wiped away both houses and bridges. It marked the volcano's first recorded eruption since the Spanish colonized the area five centuries earlier. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  14. Efecto del Programa de Entrenamiento “Manejo del Dolor” en la Documentación de Enfermería en el Expediente Electrónico

    PubMed Central

    Monsiváis, María Guadalupe Moreno; Guzmán, Ma. Guadalupe Interial; Flores, Paz Francisco Sauceda; Arreola, Leticia Vázquez

    2012-01-01

    Resumen En el presente trabajo se muestra la importancia de entrenar al personal de enfermería para mejorar la documentación en el expediente electrónico. Se eligió el manejo del dolor por ser un área prioritaria; una alta proporción de pacientes en período post operatorio cursa con dolor, por lo tanto, la documentación debe ser útil para la toma de decisiones clínicas. Se implementó un programa de entrenamiento denominado “Manejo del Dolor” dirigido al personal de enfermería. Se utilizó la tecnología de la información como herramienta para fortalecer el conocimiento con base en la revisión sistemática de la literatura; el personal de enfermería participante seleccionó la mejor evidencia; posteriormente se trabajó en la transferencia de este conocimiento a la práctica a través del diseño de un protocolo para el manejo del dolor. Se concluye que el conocimiento del manejo del dolor es fundamental para que enfermería documente con mayor precisión sus intervenciones. PMID:24199106

  15. Geological and geochemical reconnaissance in the central Santander Massif, Departments of Santander and Norte de Santander, Colombia

    USGS Publications Warehouse

    Evans, James George

    1976-01-01

    The central Santander Massif is composed of Precambrian Bucaramanga Gneiss and pre-Devonian Silgara Formation intruded by Mesozoic quartz diorite, quartz monzonite, and alaskite and Cretaceous or younger porphyry. Triassic (Bocas Formation), Jurassic (Jordan and Giron Formations).and Cretaceous (Tambor, Rosa Blanca, Paja, Tablazo, Simiti, La Luna, and Umir Formations) sedimentary rocks overlie the metamorphic rocks and are younger than most of the intrusions. A geological and geochemical reconnaissance of part of the central Santander Massif included the Vetas and California gold districts. At Vetas the gold is generally in brecciated aphanitic quartz and phyllonite. Dark-gray material in the ore may be graphite. The ore veins follow steep west-northwest- and north-northeast-striking fracture zones. No new gold deposits were found. Additional geochemical studies should concentrate on western Loma Pozo del Rey and on improvement of the gold extraction process. At California the gold is in pyritiferous quartz veins and quartz breccia. Ore containing black sooty material (graphite?) is highly radioactive. Some of the mineralization is post-Lower Cretaceous. Soil samples indicate that gold deposits lie under the thick blanket of soil on the ridges above the zone of mining. Three principal gold targets are outlined by gold and associated minerals in pan concentrates. The close relation of gold and copper anomalies suggests that copper may be useful as a pathfinder for gold elsewhere in the region. Based on occurrences of gold or high concentrations of pyrite or chalcopyrite in pan concentrates and on analytical data, eight potential gold targets are outlined in the central massif. Reconnaissance of the surrounding region is warranted.

  16. Optical gain characteristics in Al-rich AlGaN/AlN quantum wells

    SciTech Connect

    Oto, Takao; Banal, Ryan G.; Funato, Mitsuru; Kawakami, Yoichi

    2014-05-05

    The optical gain characteristics of Al-rich AlGaN/AlN quantum wells (QWs) were assessed by the variable stripe length method at room temperature. An Al{sub 0.79}Ga{sub 0.21}N/AlN QW with a well width of 5 nm had a large optical gain of 140 cm{sup −1}. Increasing the excitation length induced a redshift due to the gain consumption and the consequent saturation of the amplified spontaneous emission. Moreover, a change in the dominant gain polarization with Al composition, which was attributed to switching of the valence band ordering of strained AlGaN/AlN QWs at Al compositions of ∼0.8, was experimentally demonstrated.

  17. 35. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING E. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  18. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING E. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  19. 29. COAST LANDSCAPE VIEW FROM HIGHWAY 101, 10 MILES SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. COAST LANDSCAPE VIEW FROM HIGHWAY 101, 10 MILES SOUTH OF CRESCENT CITY. DEL NORTE COUNTY, CALIFORNIA. LOOKING S. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  20. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTE COUNTY, CALIFORNIA. LOOKING W. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  1. AL Amyloidosis and Agent Orange

    MedlinePlus

    ... for survivors' benefits . Research on AL amyloidosis and herbicides The Health and Medicine Division (formally known as ... to the compounds of interest found in the herbicide Agent Orange and AL amyloidosis." VA made a ...

  2. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  3. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  4. Atlas del Genoma del Cáncer: Antecedentes

    Cancer.gov

    El Atlas del Genoma del Cáncer es una iniciativa de los Institutos Nacionales de la Salud (NIH) para crear mapas multidimensionales completos de los cambios genómicos clave en los tipos y subtipos principales de cáncer.

  5. Studies of 27Al NMR in EuAl4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Nakamura, S.; Higa, N.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2015-03-01

    EuAl4 orders antiferromagnetically at TN ≈ 16 K with an effective magnetic moment of 8.02 μB. In the paramagnetic phase, the magnetic susceptibility of EuAl4 follows the Curie-Weiss law with a positive Curie-Weiss temperature θP = +14 K. The antiferromagnetic state is changed into the field induced ferromagnetic state at a critical field Hc of approximately 2 T. In order to microscopically investigate the magnetic and electronic properties in EuAl4, the NMR measurements of EuAl4 have been carried out at temperatures between 2 and 300 K, applying an external magnetic field of approximately 6.5 T. The 27Al NMR spectra corresponding to Al(I) and Al(II) sites are obtained. From the 27Al NMR spectra, the isotropic part Kiso and anisotropic part Kaniso of Knight shift, and nuclear quadrupole frequncy νQ are obtained. The Kiso and Kaniso shift to negative side with decreasing temperature due to the RKKY interaction. These temperature dependences follow the Curie-Weiss law with θP = +14 K, which is consistent with that of the magnetic susceptibility. From the K - χ plot, the values of the hyperfine fields Hhf_iso and Hhf_aniso are -3.231 and -0.162 kOe/μB for Al(I) site, and -1.823 and -0.264 kOe/μB for Al(II) site, respectively. The values of νQ of 27Al nucleus for Al(I) and Al(II) sites are approximately 0.865 and 0.409 MHz, respectively. The nuclear relaxation time T1 of 27Al NMR for both sites is almost constant in the paramagnetic phase, while the value of 1/T1 is abruptly decreased in the ordered ferromagnetic state.

  6. Determinacion de Caracteristicas Opticas del Telescopio OAN150

    NASA Astrophysics Data System (ADS)

    Galan, M. J.; Cobos, F. J.

    1987-05-01

    En el Observatorio de Calar Alto, en Almería, España, está ubicado un telescopio de 15O-cms de diámetro -construído por REOSC- perteneciente al Observatorio Astronómico Nacional, con sede en Madrid, España. La infraestructura técnica del OAN ha sido tradicionalmente débil y actualmente se está haciendo un esfuerzo por fortalecerla. Existe una información muy limitada del telescopio en general; de su óptica en particular se conocían los valores de los parámetros principales pero sin saber si éstos corresponden a valores teóricos ó de construcción. Por ello se consideró necesario iniciar una investigación para conocer en detalle los valores reales de las componentes ópticas del telescopio, obteniéndose algunos resultados de interés. El primario del telescopio OANl5O es aproximadamente F/3 y el siste ma en su conjunto es F/8.2, con su sistema corrector de campo. En términos generales, la imagen es satisfactoria en todo el campo y, sin sistema corrector, la imagen axial también es buena. En un futuro muy cercano se piensa diseñar instrumentación adicional para este telescopio. Conocer con mayor precisión sus características puede ser de gran utilidad para tal fin, pues se efectúan los cálculos considerando conjuntamente al telescopio y al instrumento.

  7. Interfacial characterization of Al-Al thermocompression bonds

    NASA Astrophysics Data System (ADS)

    Malik, N.; Carvalho, P. A.; Poppe, E.; Finstad, T. G.

    2016-05-01

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO2 as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400-550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO2. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO2, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO2 are discussed.

  8. Ácaros del mango

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Los ácaros constituyen un grupo abundante y diverso que ocupa diferentes hábitats en árboles frutales y la estructura y disposición del follaje y ramas del mango, contribuyen significativamente a que se presente gran diversidad de ácaros benéficos y dañinos asociados a esta especie frutal. En Colomb...

  9. Studies of 27Al NMR in SrAl4

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Higa, Nonoka; Kuroshima, Hiroko; Toji, Tatsuki; Morishima, Mach; Minei, Motofumi; Yogi, Mamoru; Nakamura, Ai; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika; Harima, Hisatomo

    A charge density wave (CDW) transition at TCDW = 243 K and a structural phase (SP) transition at approximately 100 K occur in SrAl4 with the BaAl4-type body center tetragonal structure, which is the divalent and non-4f electron reference compound of EuAl4. To understand the behaviors of the CDW and SP transitions, the 27Al NMR measurements using a single crystal and a powder sample of SrAl4 have been carried out. The line width below TCDW is modulated by an electrical quadruple interaction between 27Al nucleus and CDW charge modulation. The incommensurate CDW state below TCDW changes into a different structure below TSP. The temperature dependences of Knight shifts of 27Al(I) and 27Al(II) show the different behaviors. The temperature variation of 27Al(I) Knight shift shows anomalies at the CDW and SP transition temperatures, revealing the shift to negative side below TCDW, which is attributable to the core polarization of the d-electrons. However, 27Al(II) Knight shift keeps almost constant except for the small shift due to the SP transition. The 1/T1T of 27Al(I) indicates the obvious changes due to the CDW and SP transitions, while that of 27Al(II) takes a constant value. The density of state at the Fermi level at Al(I) site below 60 K would be about 0.9 times less than that above TCDW.

  10. ALS Performance Summary - Update

    SciTech Connect

    Waters, A M; Brown, W D; Martz, Jr., H E

    2004-09-30

    High Energy Density Physics (HEDP) experiments play an important role in corroborating the improved physics codes that underlie LLNL's Stockpile Stewardship mission. Conducting these experiments, whether on the National Ignition Facility (NIF) or another national facility such as Omega, will require not only improvement in the diagnostics for measuring the experiment, but also detailed knowledge of the as-built target components and assemblies themselves. To assist in this effort, a defined set of well-known reference standards designed to represent a range of HEDP targets have been built and are being used to quantify the performance of different characterization techniques [Hibbard, et al. 2004]. Without the critical step of using reference standards for qualifying characterization tools there can be no verification of either commercial or internally-developed characterization techniques and thus an uncertainty in the input to the physics code models would exist.

  11. Reproduccion del ganado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    La determination de prenez es una de las principales herramientas de manejo en el Ganado de came. Le habilidad de determiner prenez proporciona al productor un medio de tomar sus decsiones de seleccion y descartarte en momentos decisivos, enfocando los recursos de la operacion en reporductores confi...

  12. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    NASA Astrophysics Data System (ADS)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  13. Interpreting discrepancies between discharge and precipitation in high-altitude area of Chile's Norte Chico region (26-32°S)

    NASA Astrophysics Data System (ADS)

    Favier, Vincent; Falvey, Mark; Rabatel, Antoine; Praderio, Estelle; López, David

    2009-02-01

    The water resources of high-altitude areas of Chile's semiarid Norte Chico region (26-32°S) are studied using surface hydrological observations (from 59 rain gauges and 38 hydrological stations), remotely sensed data, and output from atmospheric prediction models. At high elevations, the observed discharge is very high in comparison with precipitation. Runoff coefficients exceed 100% in many of the highest watersheds. A glacier inventory performed with aerial photographs and ASTER images was combined with information from past studies, suggesting that glacier retreat could contribute between 5% and 10% of the discharge at 3000 m in the most glacierized catchment of the region. Snow extent was studied using MOD10A2 data. Results show that snow is present during 4 months at above 3000 m, suggesting that snow processes are crucial. The mean annual sublimation (˜80 mm a-1 at 4000 m) was estimated from the regional circulation model (WRF) and data from past studies. Finally, spatial distribution of precipitation was derived from available surface data and the global forecast system (GFS) atmospheric prediction model. Results suggest that annual precipitation is three to five times higher near the peak of the Andes than in the lowlands to the west. The GFS model suggests that daily precipitation rates in the mountains are similar to those in the coastal region, but precipitation events are more frequent and tend to last longer. Underestimation of summer precipitation may also explain part of the excess in discharge. Simple calculations show that consideration of GFS precipitation distributions, sublimation, and glacier melt leads to a better hydrological balance.

  14. Ediacaran to Cambrian magmatic suites in the Rio Grande do Norte domain, extreme Northeastern Borborema Province (NE of Brazil): Current knowledge

    NASA Astrophysics Data System (ADS)

    do Nascimento, Marcos Antonio Leite; Galindo, Antonio Carlos; de Medeiros, Vladimir Cruz

    2015-03-01

    The Ediacaran-Cambrian plutonic activity is one of the most important geological features of the Rio Grande do Norte Domain (Borborema Province, NE Brazil). It is represented by several batholiths, stocks and dykes. Based on the petrographic, geochemical and geochronological characteristic of different rocks, this plutonic activity can be grouped in six separate suites: shoshonitic (Shos), porphyritic high-K calc-alkaline (PHKCalcAlk), equigranular high K calc-alkaline (EHKCalcAlk), calc-alkaline (CalcAlk), alkaline (Alk) and charnockitic alkaline (ChAlk). Geochemically, the Shos, CalcAlk and Alk suites are differentiated from the others, while ChAlc can be distinguished from the others in some diagrams. The greatest difficulty lies in distinguishing between the chemically similar PHKCalcAlk and EHKCalcAlk. To this end, existing geochronological data as well as related petrographic and textural field aspects may be used to distinguish the two mentioned suites (PHKCalcAlk and EHKCalcAlk). Petrographically, the Shos suite has composition between gabbro/diorite and quartz monzonite. Monzogranites (with subordinate granodiorites and quartz monzonites) predominate in both PHKCalcAlk and EHKCalcAlk. Calc is composed of granodiorites to tonalites. Alc is formed by alkali feldspar granites (with subordinate alkali feldspar quartz syenites and syenogranites), whereas ChAlc has quartz mangerites and charnockites. The suites were emplaced between the Ediacaran (635-541 Ma) and Cambrian (541-485 Ma), predominantly in the Ediacaran, based on 34 U-Pb datings (zircon, titanite, monazite and columbite-tantalite), 17 Rb-Sr (whole rock) and 1 Sm-Nd (total rock and mineral) internal isochrons. The Shos suite has U-Pb ages varying from 599 ± 16 (Poço Verde pluton) to 579 ± 7 (Acari and São João do Sabugi plutons), slightly older than those of the PHKCalcAlk suite, which ranges between 591 ± 4 Ma (Totoró pluton) and 544 ± 7 Ma (São José de Espinharas pluton). The Calc

  15. Interfacial reactions and oxidation behavior of Al 2O 3 and Al 2O 3/Al coatings on an orthorhombic Ti 2AlNb alloy

    NASA Astrophysics Data System (ADS)

    Li, H. Q.; Wang, Q. M.; Gong, J.; Sun, C.

    2011-02-01

    The uniform and dense Al2O3 and Al2O3/Al coatings were deposited on an orthorhombic Ti2AlNb alloy by filtered arc ion plating. The interfacial reactions of the Al2O3/Ti2AlNb and Al2O3/Al/Ti2AlNb specimens after vacuum annealing at 750 °C were studied. In the Al2O3/Ti2AlNb specimens, the Al2O3 coating decomposed significantly due to reaction between the Al2O3 coating and the O-Ti2AlNb substrate. In the Al2O3/Al/Ti2AlNb specimens, a γ-TiAl layer and an Nb-rich zone came into being by interdiffusion between the Al layer and the O-Ti2AlNb substrate. The γ-TiAl layer is chemically compatible with Al2O3, with no decomposition of Al2O3 being detected. No internal oxidation or oxygen and nitrogen dissolution zone was observed in the O-Ti2AlNb alloy. The Al2O3/Al/Ti2AlNb specimens exhibited excellent oxidation resistance at 750 °C.

  16. Los plaguicidas y la contaminacion del medio ambiente Venezolano

    USGS Publications Warehouse

    Stickel, L.F.; Stickel, W.H.

    1972-01-01

    RESUMEN DE RECOMENDACIONES Recomendaciones para el Programa de Investigacion: 1. Establecer un sistema de muestreo biologico para detectar los niveles tendencias de los productos quimicos toxicos en un peque?o numero de si tios representativos. 2. Mantener continua vigilancia de la contaminacion ambiental, mediante la seleccion acertadamente dirigida de las zonas afectadas y de las fuentes de contaminacion. 3. Realizar estudios acerca de las poblaciones de animales silvestres, y del exito de los procesos reproductivos de las especies o grupos clayes de animales que se consideran mas gravemente afectados. 4. Preparar recomendaciones para una accion gubernamental de proteccion al hombre, a la fauna silvestre y al medio ambiente. Recomendaciones para la Accion Administrativa: 1. Establecer limites a la tolerancia de los residuos de plaguicidas en los alimentos. Constituye una medida clave para disminuir la contaminacion ambiental. 2. Establecer normas de calidad del agua para las corrientes, represas, la gos y otros cuerpos. Es la segunda medida clave para reducir la contaminacion del ambiente 3. Exigir un tratamiento adecuado de los efluentes industriales, especialmente antes de que se construyan las nuevas plantas. 4. Exigir a los agricultores que en el uso de plaguicidas sigan los consejos tecnicos autorizados y negar a los vendedores el derecho a recomendar productos por su cuenta. 5. Tomar medidas para recoger y eliminar los recipientes y sobrantes de los plaguicidas.

  17. Informe del NCI y los CDC sobre el tabaco sin humo

    Cancer.gov

    El primer informe sobre el consumo mundial del tabaco sin humo y sus consecuencias en la salud pública reveló que más de 300 millones de personas en al menos 70 países usan estos productos dañinos.

  18. Rub' al Khali, Arabia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.

    The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  19. al-Sufi, Abu al-Rahman (903-86)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Persian astronomer, published works on astronomical instruments. Revised PTOLEMY's star catalog as the Book of the Constellations of the Fixed Stars, with improved magnitudes, stars named by reference to constellation figures (much copied, for example by ALFONSO X as Libros del Saber de Astronomìa), and nebulae, including the Andromeda Galaxy (M31). However, the work was not entirely original sin...

  20. Violación del Principio de Equivalencia en Teorías con Dilatón de Cuerdas

    NASA Astrophysics Data System (ADS)

    Landau, S. J.; Sisterna, P. D.; Vucetich, H.

    Se estudian las violaciones al Principio de Equivalencia en Teorías con Dilatón de Cuerdas. En estos modelos, algunas de las constantes fundamentales dependen del espacio y del tiempo. Se muestra que los experimentos de caída libre no tienen aún precisión como para poner límites a los parámetros de la teoría.

  1. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  2. Undulators at the ALS

    SciTech Connect

    Hoyer, E.; Akre, J.; Chin, J.

    1994-07-01

    At Lawrence Berkeley Laboratory`s (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/{minus} 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10{sup {minus}11} Torr range and storage ring operating pressures with full current are in the low 10{sup {minus}10} Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented.

  3. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    NASA Astrophysics Data System (ADS)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-07-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  4. Case Study: del Amo Bioventing

    EPA Science Inventory

    The attached presentation discusses the fundamentals of bioventing in the vadose zone. The basics of bioventing are presented. The experience to date with the del Amo Superfund Site is presented as a case study.

  5. Modeling neuronal vulnerability in ALS.

    PubMed

    Roselli, Francesco; Caroni, Pico

    2014-08-20

    Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS. PMID:25144872

  6. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    NASA Astrophysics Data System (ADS)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  7. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  8. Stimulated emission in AlGaN/AlGaN quantum wells with different Al content

    NASA Astrophysics Data System (ADS)

    Mickevičius, J.; Jurkevičius, J.; Kazlauskas, K.; Žukauskas, A.; Tamulaitis, G.; Shur, M. S.; Shatalov, M.; Yang, J.; Gaska, R.

    2012-02-01

    Stimulated emission (SE) is studied in AlGaN/AlGaN multiple quantum wells (MQWs) with different Al content grown on sapphire substrate. The spectra of spontaneous and stimulated emission and their transformations with increasing temperature as well as stimulated emission thresholds were measured in the temperature range from 8 to 300 K. Phonon-assisted band broadening in low-Al-content MQWs and double-scaled potential profile in high-Al-content MQWs were observed in the samples and linked with carrier localization conditions. The temperature dependence of the stimulated emission threshold was similar in the samples where the stimulated transitions occur between extended states and in the samples where the transitions occur in localized states. The stimulated emission threshold depends predominantly on the density of nonradiative recombination centers.

  9. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  10. Ediacaran to Cambrian magmatic suites in the Rio Grande do Norte domain, extreme Northeastern Borborema Province (NE of Brazil): Current knowledge

    NASA Astrophysics Data System (ADS)

    do Nascimento, Marcos Antonio Leite; Galindo, Antonio Carlos; de Medeiros, Vladimir Cruz

    2015-03-01

    The Ediacaran-Cambrian plutonic activity is one of the most important geological features of the Rio Grande do Norte Domain (Borborema Province, NE Brazil). It is represented by several batholiths, stocks and dykes. Based on the petrographic, geochemical and geochronological characteristic of different rocks, this plutonic activity can be grouped in six separate suites: shoshonitic (Shos), porphyritic high-K calc-alkaline (PHKCalcAlk), equigranular high K calc-alkaline (EHKCalcAlk), calc-alkaline (CalcAlk), alkaline (Alk) and charnockitic alkaline (ChAlk). Geochemically, the Shos, CalcAlk and Alk suites are differentiated from the others, while ChAlc can be distinguished from the others in some diagrams. The greatest difficulty lies in distinguishing between the chemically similar PHKCalcAlk and EHKCalcAlk. To this end, existing geochronological data as well as related petrographic and textural field aspects may be used to distinguish the two mentioned suites (PHKCalcAlk and EHKCalcAlk). Petrographically, the Shos suite has composition between gabbro/diorite and quartz monzonite. Monzogranites (with subordinate granodiorites and quartz monzonites) predominate in both PHKCalcAlk and EHKCalcAlk. Calc is composed of granodiorites to tonalites. Alc is formed by alkali feldspar granites (with subordinate alkali feldspar quartz syenites and syenogranites), whereas ChAlc has quartz mangerites and charnockites. The suites were emplaced between the Ediacaran (635-541 Ma) and Cambrian (541-485 Ma), predominantly in the Ediacaran, based on 34 U-Pb datings (zircon, titanite, monazite and columbite-tantalite), 17 Rb-Sr (whole rock) and 1 Sm-Nd (total rock and mineral) internal isochrons. The Shos suite has U-Pb ages varying from 599 ± 16 (Poço Verde pluton) to 579 ± 7 (Acari and São João do Sabugi plutons), slightly older than those of the PHKCalcAlk suite, which ranges between 591 ± 4 Ma (Totoró pluton) and 544 ± 7 Ma (São José de Espinharas pluton). The Calc

  11. In memory of Al Cameron

    NASA Astrophysics Data System (ADS)

    Cowan, John; Truran, James W.

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning ele- ment formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

  12. Reply to Gopalswamy et al.

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.

    2003-01-01

    The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

  13. Understanding Changes in Water Availability in the Rio Grande/Rio Bravo del Norte Basin Under the Influence of Large-Scale Circulation Indices Using the Noah Land Surface Model

    NASA Technical Reports Server (NTRS)

    Khedun, C. Prakash; Mishra, Ashok K.; Bolten, John D.; Beaudoing, Hiroko K.; Kaiser, Ronald A.; Giardino, J. Richard; Singh, Vijay P.

    2012-01-01

    Water availability plays an important role in the socio-economic development of a region. It is however, subject to the influence of large-scale circulation indices, resulting in periodic excesses and deficits. An assessment of the degree of correlation between climate indices and water availability, and the quantification of changes with respect to major climate events is important for long-term water resources planning and management, especially in transboundary basins as it can help in conflict avoidance. In this study we first establish the correlation of the Pacific Decadal Oscillation (PDO) and El Nino-Southern Oscillation (ENSO) with gauged precipitation in the Rio Grande basin, and quantify the changes in water availability using runoff generated from the Noah land surface model. Both spatial and temporal variations are noted, with winter and spring being most influenced by conditions in the Pacific Ocean. Negative correlation is observed at the headwaters and positive correlation across the rest of the basin. The influence of individual ENSO events, classified using four different criteria, is also examined. El Ninos (La Ninas) generally cause an increase (decrease) in runoff, but the pattern is not consistent; percentage change in water availability varies across events. Further, positive PDO enhances the effect of El Nino and dampens that of La Nina, but during neutral/transitioning PDO, La Nina dominates meteorological conditions. Long El Ninos have more influence on water availability than short duration high intensity events. We also note that the percentage increase during El Ninos significantly offsets the drought-causing effect of La Ninas.

  14. Seminario Tecnico Regional Sobre Alternativas de Educacion Basica de Adultos en el Marco de la REDALF del Proyecto Principal de Educacion en America Latina y el Caribe (Colonia Tovar, Venezuela, 29 de Septiembre al 3 de Octubre, 1986). Documento Final. (Regional Seminar on Alternatives for Basic Adult Education in the REDALF Project for Education in Latin America and the Caribbean (Colonia Tovar, Venezuela, September 29-October 3, 1986). Final Document.)

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Santiago (Chile). Regional Office for Education in Latin America and the Caribbean.

    The final report of a conference concerning adult basic education de Adultos en el Marco de la REDALF del related to innovative projects in adult education in nine countries. A wide spectrum of issues related to adult basic education, curriculum, methodology, evaluation, and research are analyzed in the context of educational planning. Among the…

  15. Percepcion de los profesores universitarios acerca del concepto cultura cientifica y de sus implicaciones en el nuevo bachillerato del Recinto de Rio Piedras de la Universidad de Puerto Rico

    NASA Astrophysics Data System (ADS)

    Ramos Pastrana, Nilsa

    El Senado Academico del Recinto de Rio Piedras de la Universidad de Puerto Rico aprobo en el ano academico 2005-2006 la Certificacion 46, que contiene los lineamientos de un nuevo bachillerato. Este nuevo bachillerato introdujo cambios significativos en el curriculo tradicional. Entre ellos se encuentra la reduccion del componente de educacion general y el de Ciencias Biologicas en particular. La reduccion de creditos en el componente de Ciencias Biologicas ha obligado a reevaluar el concepto de cultura cientifica que desarrollan esos cursos. El proposito del estudio consistio en auscultar las percepciones de los profesores de las Facultades de Administracion de Empresas, Humanidades, Ciencias Sociales, Ciencias Naturales, Educacion y Estudios Generales del Recinto de Rio Piedras de la Universidad de Puerto Rico en torno al concepto de cultura cientifica, los contenidos disciplinares del curso de Ciencias Biologicas y la reduccion de creditos en el nuevo bachillerato. Las preguntas que guiaron la investigacion fueron: ¿cuales son las percepciones que tienen los profesores de las Facultades de Administracion de Empresas, Ciencias Sociales, Estudios Generales, Ciencias Naturales, Humanidades y Educacion, en torno al concepto de cultura cientifica y los contenidos disciplinares del curso de Ciencias Biologicas? ¿cuales son las percepciones que tienen los profesores de Ciencias Biologicas en torno al concepto cultura cientifica y los contenidos disciplinares del curso de Ciencias Biologicas? ¿existen diferencias significativas por facultad, genero, experiencia, rango y nombramiento en las percepciones que tienen los profesores del Recinto de Rio Piedras de la Universidad de Puerto Rico sobre los elementos que caracterizan la cultura cientifica y los contenidos biologicos que deben tener los egresados del Recinto? ¿que implicaciones curriculares tienen estos testimonios en el desarrollo del concepto de cultura cientifica en el nuevo bachillerato? Para realizar la

  16. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

  17. Corrosion Behavior of Al-Al3Ni and Al-Al2Cu Functionally Graded Materials Fabricated by a Centrifugal Method

    NASA Astrophysics Data System (ADS)

    Noda, Kazuhiko; Miyahara, Keita; Watanabe, Yoshimi

    2008-02-01

    Intermetallic compounds, such as Al3Ni and Al2Cu, are effective for enhancing the mechanical properties of an alloy. Al-Al3Ni and Al-Al2Cu functionally graded materials (FGMs) might be attractive materials for advanced materials. Al-Al3Ni and Al-Al2Cu FGMs were fabricated by a centrifugal method; the centrifugal method is an extremely effective method for fabricating FGMs. Al-Al3Ni and Al-Al2Cu FGMs that had a graded distribution of intermetallic compounds could be produced by this in-situ centrifugal method. Particle size, particle shape and the distribution of intermetallic compounds were controlled by varying the content of the alloy element (Ni, Cu) in the master alloy, the cooling rate in casting and the gravity number. The casting mechanism is explained in terms of the microstructures of the Al-Al3Ni and Al-Al2Cu FGMs fabricated by this method. The corrosion behavior of the FGMs was investigated by electrochemical analysis. Polarization curves of the FGMs in a borate solution were measured by a potentiodynamic method. The presence of Al2Cu exerted a larger effect on the corrosion behavior of the FGMs than Al3Ni. Analysis of the polarization curve parameters was effective for evaluating the corrosion resistance of the FGMs.

  18. Stratigraphic and structural analysis of the Neogene sediments of the offshore portion of the Salina del Istmo Basin, southeastern Mexico

    NASA Astrophysics Data System (ADS)

    Gomez-Cabrera, Pedro Tomas

    2003-10-01

    Southeastern Mexico has been affected by regional and local tectonic events. Regional tectonic events are the Gulf of Mexico opening and the lateral movement of micro-plates on the Pacific margin. The local tectonic events are related to salt tectonics. Autochthonous Jurassic salt serves as the detachment level for the main compressional event in the late Miocene. Jurassic salt was allochthonously emplaced in the late Miocene, then partially displaced by a huge quantity of terrigenous sediments during the Plio-Pleistocene. This research is a study of the main geological processes that have influenced the structural and stratigraphic evolution of the Neogene sediments in the offshore portion of the Salina del Istmo basin known as the Marbella area. Owing to data availability, the project was divided into regional and local studies. The regional study is based on 2D multi-channel seismic reflection data, and the local study is based on a 3D seismic streamer survey. Structural analysis in the regional study permits the recognition of four buried fold belts (Agua Dulce, Catemaco, Marbella, and Marbella Norte) trending roughly NE. These fold belts are the result of tectonic convergence in the pacific margin during late Miocene. The Agua Dulce and Marbella Norte fold belts are separated by an enormous salt withdrawal basin called the Pescadores basin. The Pescadores basin is bounded on the north by a spectacular stepped, counter-regional structure. Beyond the Pescadores basin, a salt mini-basin area is recognized in the upper continental slope. Another important structural element is the Sal Somera canopy in the southern part of the study area. Sedimentation-rate analysis, based on isochore mapping in the local study area, indicates that from SB-2.4 to SB-2.6 Ma, deposition rate peaked with a maximum of 7.5 mm/yr. Regional and local structural restorations show that, in general, the maximum allochthonous salt mobilization was during the Plio-Pleistocene because of the

  19. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    NASA Astrophysics Data System (ADS)

    Yadav, S. K.; Wang, J.; Liu, X.-Y.

    2016-06-01

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. The formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  20. High Density Sliding at Ta/Al and Al/Al Interfaces

    SciTech Connect

    Hammerberg, J. E.; Germann, T. C.; Ravelo, R.

    2006-07-28

    We present 3D-nonequilibrium molecular dynamics results for the velocity dependence of the frictional force at smooth sliding interfaces for Ta and Al single crystals. For Ta/Al we consider Al(100)/Ta(100) and Al(111)/Ta(110) interfaces sliding along [001] and [11(bar sign)0]fcc /[001]bcc respectively. These are compared with Al(111)/Al(100) interfaces at the same loads, corresponding to a pressure of 15 GPa. Both interfacial pairs show similar behavior in the velocity dependence of the frictional force: a low velocity regime with an increasing frictional force followed by a strain induced transformation regime at velocities above approximately 1/10 the transverse sound speed, followed by a fluidized interface at high velocities. For both interfacial pairs, the high velocity dependence of the frictional force exhibits power law behavior, Ft {proportional_to} v-{beta} with {beta}=3/4. We discuss the structural changes that influence dissipation in each of these regimes.

  1. El uso de la neuromodulación para el tratamiento del temblor

    PubMed Central

    Bendersky, Damián; Ajler, Pablo; Yampolsky, Claudio

    2014-01-01

    Introducción: El temblor puede ser un desorden incapacitante y el tratamiento de primera línea para estos pacientes es farmacológico. Sin embargo, este tratamiento puede llevar a una reducción satisfactoria del temblor en sólo el 50% de los pacientes con temblor esencial. La talamotomía era el tratamiento de elección para el temblor refractario al tratamiento médico hasta que comenzó a utilizarse la estimulación cerebral profunda (ECP) del núcleo ventral intermedio (Vim) del tálamo. En la actualidad, raramente se realiza la talamotomía. Métodos: Este artículo es una revisión no sistemática de las indicaciones, resultados, parámetros de programación y técnica quirúrgica de la ECP del Vim para el tratamiento del temblor. Resultados: Aunque los resultados clínicos son similares usando la talamotomía o la ECP del Vim, la primera causa más efectos adversos que la última. Además, la ECP puede ser usada bilateralmente, mientras que la talamotomía tiene un alto riesgo de causar disartria cuando se realiza de ambos lados. La ECP del Vim logró una adecuada mejoría del temblor en varias series de pacientes con temblor causado por temblor esencial, enfermedad de Parkinson o esclerosis múltiple. Además del Vim, hay otros blancos que están siendo usados por varios autores, tales como la zona incerta y las radiaciones prelemniscales. Conclusión: La ECP del Vim es un tratamiento útil para el temblor incapacitante refractario al tratamiento médico. Es esencial realizar una precisa selección de pacientes, así como utilizar una técnica quirúrgica correcta. Aún se desconoce el mejor blanco estereotáctico para el temblor, aunque el Vim es el más usado. PMID:25165613

  2. Vacunas contra los virus del papiloma humano

    Cancer.gov

    Una hoja informativa acerca de las vacunas contra los virus del papiloma humano (VPH) para prevenir infecciones con ciertos tipos de VPH, los cuales son la causa principal del cáncer de cuello del útero o cérvix.

  3. Observación y registro fotográfico del cometa HYAKUTAKE C/1996 B2

    NASA Astrophysics Data System (ADS)

    Arquiola, A. P.; Arquiola, F. E.

    Desde el momento en que nos llega la información del descubrimiento, comenzamos la observación de forma detallada a fin de apreciar y seguir su creciente actividad. La primera observación se realizó el 17 de febrero de 1996 a las 4h20m UT con nuestro telescopio de 300mm newtoniano de f/6.5, con una muy buena transparencia atmosférica, estimando una magnitud de 8.5. Realizábamos observaciones casi todas las noches, mientras nos lo permitían las condiciones climáticas. Ya el 26 de febrero el cometa presentaba un aspecto muy particular, ligeramente distinto a las primeras observaciones, ya que comenzamos a notar su gran actividad. En primer lugar se destacaba la cola de iones mucho mas extensa que la cola de polvo. Magnitud estimada 7.5. El 19 de marzo ya era visible a simple vista y en especial su cola muy abierta y extensa (3 grados) y no quedaba duda alguna que la última noche de observación del cometa en el horizonte de la Ciudad de Funes, que fue el 24 de marzo de 1996, un día antes del acercamiento a la Tierra, tendríamos una apreciación del cometa en su máximo esplendor. El 24 de marzo de 1996 a las 4hs UT, asomó el cometa por el horizonte NE, con su cola espectacular, llegando a medir 23 grados de longitud, muy recta y brillante, y su cabellera muy estelar. A este marco de observación se sumaron mas de 600 personas que participaron usando instrumentos, siendo la mayoría de los concurrentes de la vecina Ciudad de Rosario, ya que su observación era a muy baja atura sobre el horizonte norte. Instrumentos utilizados : Telescopio Newtoniano 300mm f/6.5, Telescopio Schmidt-Cassegrain 200mm , Binoculares 10 x 50, 7 x 50, Lente normal 50mm a f/1.8, Película 100 - 400 ASA Lugar de Observación : Ciudad de Funes, zona rural, ``Estancia La Polola" Latitud: - 32o 55' Longitud: 60o 40' Oeste

  4. Superconductivity in Al/Al2O3 interface

    NASA Astrophysics Data System (ADS)

    Palnichenko, A. V.; Vyaselev, O. M.; Mazilkin, A. A.; Khasanov, S. S.

    2016-06-01

    Metastable superconductivity at Tc ≈ 65 K has been observed in Al foil subjected to special oxidation process, according to the ac magnetic susceptibility and electrical resistance measurements. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed during the oxidation process between metallic aluminum and its oxide.

  5. AlN/Fe/AlN nanostructures for magnetooptic magnetometry

    SciTech Connect

    Lišková-Jakubisová, E. Višňovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.

    2014-05-07

    AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of λ = 410 nm (3.02 eV) and operate at oblique light incidence angles, φ{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at φ{sup (0)} ≈ 5° and longitudinal Kerr effect spectra (φ{sup (0)} = 45°) at photon energies between 1 and 5 eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

  6. ALS - A unique design approach

    NASA Astrophysics Data System (ADS)

    Chamberlain, Roger A.

    1990-09-01

    An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

  7. La meridiana di Egnazio Danti nella Torre dei Venti in Vaticano: un'icona della riforma Gregoriana del calendario

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2014-05-01

    La Torre dei Venti domina l’angolo Sud Ovest del cortile della Pigna (nell'area dei Musei Vaticani), ed è inclusa negli ambienti dell'Archivio Segreto Vaticano. Non è aperta al pubblico, ma è universalmente nota per la fama che da oltre quattrocento anni la circonda, legata alle vicende della riforma Gregoriana del calendario. La meridiana tracciata da padre Egnazio Danti (1536-1586) nella torre dei Venti, fu visitata anche da Gregorio XIII, probabilmente il 21 marzo 1581 come suppone il padre Stein, per convincersi dell'anticipo ormai arrivato a dieci giorni dell'equinozio di primavera sulla data che il concilio di Nicea aveva fissato al 21 marzo per il computo pasquale. La ricognizione astrometrica del febbraio-marzo 2009 fatta dall'autore viene qui presentata.

  8. The ants of North and Central America: the genus Mycocepurus (Hymenoptera: Formicidae)

    PubMed Central

    Mackay, William P.; Maes, Jean-Michel; Fernández, Patricia Rojas; Luna, Gladys

    2004-01-01

    Abstract We provide a review of the North American ants (north of Colombia) of the ant genus Mycocepurus, including keys to the workers and females, illustrations and distribution maps. The distribution of M. tardus is extended to Nicaragua and Costa Rica. The female of M. curvispinosus is described. Resumen Se revisan las especies del género Mycocepurus de Norte América (al norte de Colombia). Se incluyen claves para la identificación de las obreras y las hembras, ilustraciones y mapas de distribución. Se amplia hacia el norte la distribución de M. tardus, incluyendo ahora Nicaragua y Costa Rica y se describe la hembra de M. curvispinosus. PMID:15861242

  9. Mini-mastoidectomía para anastomosis hipogloso-facial con sección parcial del nervio hipogloso

    PubMed Central

    Campero, Álvaro; Ajler, Pablo; Socolovsky, Mariano; Martins, Carolina; Rhoton, Albert

    2012-01-01

    Introducción: La anastomosis hipogloso-facial es la técnica de elección para la reparación de la parálisis facial cuando no se dispone de un cabo proximal sano del nervio facial. La técnica de anastomosis mediante fresado mastoideo y sección parcial del hipogloso minimiza la atrofia lingual sin sacrificar resultados a nivel facial. Método: La porción mastoidea del nervio facial transcurre por la pared anterior de la AM, a un promedio de 18+/-3 mm de profundidad respecto de la pared lateral. Se debe reconocer la cresta supramastoidea, desde la cual se marca una línea vertical paralela al eje mayor de la AM, 1 cm por detrás de la pared posterior del CAE El fresado se comienza desde la línea medio mastoidea hasta la pared posterior del CAE. Una vez encontrado el nervio facial en el tercio medio del canal mastoideo, el mismo es seguido hacia proximal y distal. Resultados: El abordaje descripto permite acceder al nervio facial intratemporal en su porción mastoidea, y efectuar un fresado óseo sin poner en riesgo al nervio o a estructuras vasculares cercanas. Se trata de un procedimiento técnicamente más sencillo que los abordajes amplios habitualmente utilizados al hueso temporal; no obstante su uso debe ser restringido mayormente a la anastomosis hipogloso-facial. Conclusión: Esta es una técnica relativamente sencilla, que puede ser reproducida por cirujanos sin mayor experiencia en el tema, luego de su paso por el laboratorio de anatomía. PMID:23596555

  10. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  11. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  12. La implantacion del enfoque constructivista en el aula de ciencia: Estudio de caso multiple

    NASA Astrophysics Data System (ADS)

    Arroyo Betancourt, Luz I.

    Esta investigacion estudia la implantacion del enfoque constructivista en tres aulas de ciencia del contexto puertorriqueno. Se auscultaron las practicas educativas que utilizan maestras consideradas constructivistas y la correspondencia de sus practicas educativas con los elementos esenciales de la didactica que proponen los teoricos de los planteamientos constructivistas. Se ausculto, ademas, a que vision del enfoque constructivista responden las expresiones de las maestras acerca de su practica educativa y como compara con su quehacer, a la luz de los elementos esenciales de las visiones constructivistas piagetiana, social y radical. Se utilizo el diseno de estudio descriptivo de caso multiple. El estudio se baso en entrevistas a profundidad, revision de documentos y observacion no participativa a la sala de clases. El contexto fueron tres escuelas publicas de la Region Educativa de San Juan, una elemental, una intermedia y una superior. Los resultados confirmaron que la transicion hacia el enfoque constructivista es un proceso que toma tiempo, dedicacion y la participacion en adiestramientos y readiestramientos acerca del nuevo enfoque. Las maestras coinciden en la mayoria de las practicas educativas que utilizan para implantar el enfoque constructivista de ensenanza y difieren en algunas debido, probablemente, a que han tenido que adaptarlas a los correspondientes niveles de ensenanza: elemental, intermedio y superior. Dos de las maestras planifican por conceptos generadores, mientras que una de ellas planifica siguiendo la guia que recibe del Departamento de Educacion. Difieren ademas, en el enfasis que confieren al inquirir cientifico. Con relacion a la correspondencia entre la vision manifestada por las maestras a la luz de las visiones piagetiana, social y radical, aparentemente, las preguntas del protocolo de entrevistas no lograron evocar la informacion con suficiente profundidad, por lo que la investigadora tuvo que inferir las visiones de las

  13. AlSb/InAs/AlSb quantum wells

    NASA Technical Reports Server (NTRS)

    Kroemer, Herbert

    1990-01-01

    Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

  14. DelPhi: a comprehensive suite for DelPhi software and associated resources

    PubMed Central

    2012-01-01

    Background Accurate modeling of electrostatic potential and corresponding energies becomes increasingly important for understanding properties of biological macromolecules and their complexes. However, this is not an easy task due to the irregular shape of biological entities and the presence of water and mobile ions. Results Here we report a comprehensive suite for the well-known Poisson-Boltzmann solver, DelPhi, enriched with additional features to facilitate DelPhi usage. The suite allows for easy download of both DelPhi executable files and source code along with a makefile for local installations. The users can obtain the DelPhi manual and parameter files required for the corresponding investigation. Non-experienced researchers can download examples containing all necessary data to carry out DelPhi runs on a set of selected examples illustrating various DelPhi features and demonstrating DelPhi’s accuracy against analytical solutions. Conclusions DelPhi suite offers not only the DelPhi executable and sources files, examples and parameter files, but also provides links to third party developed resources either utilizing DelPhi or providing plugins for DelPhi. In addition, the users and developers are offered a forum to share ideas, resolve issues, report bugs and seek help with respect to the DelPhi package. The resource is available free of charge for academic users from URL: http://compbio.clemson.edu/DelPhi.php. PMID:22583952

  15. The effect of Si in Al-alloy on electromigration performance in Al filled vias

    NASA Astrophysics Data System (ADS)

    Kageyama, Makiko; Hashimoto, Keiichi; Onoda, Hiroshi

    1998-01-01

    Electromigration performance of vias filled with Al-Si-Cu alloys on Ti glue layers was investigated in comparison with W-stud vias. In Al-Si-Cu filled vias, voids were formed at only a few locations in the test structure, while voids were formed at every via in W-stud via chains. It is supposed that Al moves through the Al-Si-Cu via during electromigration in spite of the existence of a glue layer at the via bottom. This phenomenon was observed only in the vias filled with Al-Si-Cu alloy. Al movement was prohibited in Al-Cu filled vias. In Al-Si-Cu filled vias, an Al-Ti-Si alloy was formed at the via bottom while Al3Ti was formed at Al-Cu filled vias. Al is speculated to move through this Al-Ti-Si alloy during electromigration.

  16. Emerging mechanisms of molecular pathology in ALS

    PubMed Central

    Peters, Owen M.; Ghasemi, Mehdi; Brown, Robert H.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable. PMID:25932674

  17. Etologia aplicada al manejo de especies amenazadas: el caso del turon de patas negras (Mustela nigripes)

    USGS Publications Warehouse

    Vargas, A.; Biggins, D.; Miller, B.

    1999-01-01

    de esta especie de un modo más eficaz y rentable. Black-footed ferrets are considered one of the world's most endangered mammals. The last wild population was discovered in 1981 in Meteetsee, Wyoming, and, in 1985 it collapsed due to an epizootic of canine distemper in combination with sylvatic plague. Prior to the extinction of the last remnant population, 18 wild black-footed ferrets were captured to initiate captive propagation efforts. Captive breeding has been successful and, during the last 11 years, more than 2600 black-footed ferrets have been born in captive breeding centers. Since 1991, approximately 870 ferrets have been reintroduced in 5 areas located within the ferret's original geographic distribution, including sites in Wyoming, Montana, South Dakota, and Arizona. Scientific research has been, and continues to be, a critical tool to direct recovery efforts. Studies in applied ethology conducted on captive and reintroduced ferret populations have demonstrated that a naturalistic captive environment, particularly during early developmental periods, enhances the expression of behaviors necessary for survival in nature. Ferrets raised in a naturalistic environment develop better predatory skills, are able to recognize prairie dog burrows as a home and shelter from predators, and are more physically fit. Results from these studies have been adapted into management strategies to help implement a more cost-effective road to black-footed ferret recovery.

  18. Resumenes Analiticos en Education del 0001 al 0230 (Analytic Resumes in Education, from 0001 to 0230).

    ERIC Educational Resources Information Center

    Scott, Patrick B., Ed.

    1991-01-01

    REDUC is a cooperative network of some 23 associated centers in 17 Latin American and Caribbean countries. The REDUC coordinating center is located in Santiago, Chile. REDUC produces a bibliographic database containing analytical summaries (approximately 800 items annually) of the most important research studies and project descriptions in the…

  19. L'inserimento del bambino al nido (Welcoming the Child into Child Care): Perspectives from Italy.

    ERIC Educational Resources Information Center

    Bove, Chiara

    1999-01-01

    Describes various approaches taken by Italian child-care programs to facilitate the young child's transition into a child care setting. Discusses the role of teachers as researchers, the role of parents as partners, and the benefits to young children. (KB)

  20. Tierra del Fuego, Argentina, South America

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Mitre Peninsula is the easternmost tip of Tierra del Fuego, Argentina, (54.5S, 65.5W). Early winter snow can be seen on this south tip of the Andes Mountains. These same mountains continue underwater to Antarctica. The Strait of Magellan, separating the South American mainland from Tierra del Fuego is off the scene to the north and west, but the Strait of LeMaire, separating Tierra del Fuego from the Isla de los Estados can be seen.

  1. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    DOE PAGESBeta

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-14

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamicallymore » driven process.« less

  2. Synthesis of AlN/Al Polycrystals along with Al Nanoparticles Using Thermal Plasma Route

    SciTech Connect

    Kanhe, Nilesh S.; Nawale, A. B.; Kulkarni, N. V.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2011-07-15

    This paper for the first time reports the (200) oriented growth of hexagonal Aluminum nitride crystals during synthesis of aluminum nanoparticles in dc transferred arc thermal plasma reactor by gas phase condensation in nitrogen plasma. The structural and morphological study of as synthesized AlN crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.

  3. Synthesis of Al-Al2O3 and Al-Aln Nanoparticle Composites Via Electric Explosion of Wires

    NASA Astrophysics Data System (ADS)

    Lerner, M. I.; Lozhkomoev, A. S.; Pervikov, A. V.; Bakina, O. V.

    2016-07-01

    Composite Al-Al2O3 and Al-AlN nanoparticles were synthesized via electric explosion of aluminum wires in an argon-oxygen gas mixture and in nitrogen. The parameters of electric explosion and gas medium affect the size and relative content of nitride and aluminum oxide in the nanoparticles. Processes of forming chemical compounds during aluminum oxidation at the contact surface between explosive products and gas and of nitrogen diffusions into the nanoparticles of the condensed phase are considered.

  4. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-09-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  5. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-05-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  6. NiAl-base composite containing high volume fraction of AlN for advanced engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan (Inventor); Whittenbeger, John D. (Inventor); Lowell, Carl F. (Inventor)

    1994-01-01

    A particulate reinforced NiAl-AlN composite alloy has a NiAl matrix and greater than about 13 volume percent fine particles of AlN within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced NiAl-AlN composite alloy may be prepared by cryomilling prealloyed NiAl in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced NiAl-AlN composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCrAlY, FeCrAlY, and FeAl.

  7. 77 FR 73732 - In the Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka The... al-Rafidayn, aka The Organization of al-Jihad's Base of Operations in Iraq, aka al-Qaida of Jihad in Iraq, aka al-Qaida in Iraq, aka al-Qaida in Mesopotamia, aka al-Qaida in the Land of the Two...

  8. The Al-Al3Ni Eutectic Reaction: Crystallography and Mechanism of Formation

    NASA Astrophysics Data System (ADS)

    Fan, Yangyang; Makhlouf, Makhlouf M.

    2015-09-01

    The characteristics of the Al-Al3Ni eutectic structure are examined with emphasis on its morphology and crystallography. Based on these examinations, the mechanism of formation of this technologically important eutectic is postulated. It is found that a thin shell of α-Al forms coherently around each Al3Ni fiber. The excellent thermal stability of the Al-Al3Ni eutectic may be attributed to the presence of this coherent layer.

  9. Reply to Pachai et al.

    PubMed

    Harrison, William J; Bex, Peter J

    2016-05-01

    Peripheral vision is fundamentally limited by the spacing between objects. When asked to report a target's identity, observers make erroneous reports that sometimes match the identity of a nearby distractor and sometimes match a combination of target and distractor features. The classification of these errors has previously been used to support competing 'substitution' [1] or 'averaging' [2] models of the phenomenon known as 'visual crowding'. We recently proposed a single model in which both classes of error occur because observers make their reports by sampling from a biologically-plausible population of weighted responses within a region of space around the target [3]. It is critical to note that there is no probabilistic substitution or averaging process in our model; instead, we argue that neither substitution nor averaging occur, but that these are misclassifications of the distribution of reports that emerge when a population response distribution is sampled. This is a fundamentally different way of thinking about crowding, and on this basis we claim to have provided a mechanism unifying categorically distinct perceptual errors. Our goal was not to model all crowding phenomena, such as the release from crowding when target and flanks differ in color or depth [4]. Pachai et al.[5] have suggested that our model is not unifying because it inaccurately predicts perceptual performance for a particular stimulus. Although we agree that our model does not predict their data, this specific demonstration overlooks the critical aspect of the model: perceptual reports are drawn from a weighted population code. We show that Pachai et al.'s [5] own data actually provide evidence for the population code we have described [3], and we suggest a biologically-plausible analysis of their stimuli that provides a computational basis for their 'grouping' account of crowding. PMID:27166690

  10. Líneas Vitales: Programas y servicios del NCI

    Cancer.gov

    Artículos y videos sobre los programas y servicios del Instituto Nacional del Cáncer de la serie educativa Líneas Vitales del NCI, la cual está dirigida especialmente a poblaciones multiculturales.

  11. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jaing, Y; He, Y H; Xu, N P; Zou, J; Huang, B; Lui, C T

    2008-01-01

    Porous TieAl alloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porous TieAl alloys can have three crystalline phases (i.e., a2-Ti3Al, g-TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  12. Everyday Life with ALS: A Practical Guide

    MedlinePlus

    ... course of ALS. ALS also will require some adaptations to your environment, both for safety and to ... the way, Chapter 6 will include information on adaptations for computer access. Though the chapter is called “ ...

  13. Benefits for Military Veterans with ALS

    MedlinePlus

    ... Chapters Certified Centers and Clinics Support Groups About ALS About Us Our Research In Your Community Advocate ... Veterans Resources for Military Veterans, Families & Survivors The ALS Association is working everyday to support people with ...

  14. Control del cáncer y salud mundial: noticia del Instituto Nacional del Cáncer (NCI)

    Cancer.gov

    En combinación con una reunión de alto nivel de las Naciones Unidas sobre enfermedades no transmisibles en países en vías de desarrollo, el doctor Harold Varmus, director del NCI, y el doctor Ted L. Trimble, del NCI, han publicado un comentario en Science

  15. Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions

    SciTech Connect

    Ruiz-Salvador, A. Rabdel; Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W.

    2013-02-15

    We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

  16. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH2(Al)

    NASA Astrophysics Data System (ADS)

    An, Yang; Li, Huiliang; Liu, Yuanyuan; Huang, Baibiao; Sun, Qilong; Dai, Ying; Qin, Xiaoyan; Zhang, Xiaoyang

    2016-01-01

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH2 (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO6-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.

  17. Determinacion de periodos fundamentales del suelo mediante vibraciones ambientales en el municipio de Humacao, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Cintron Aponte, Rommel

    La tecnica de Nakamura ha sido utilizada a nivel mundial para determinar periodos fundamentales del suelo. La tecnica consiste en calcular y graficar cocientes espectrales H/V de vibraciones ambientales registradas sobre el suelo. Mediciones de vibraciones ambientales fueron tomadas en 151 lugares dentro del municipio de Humacao, localizado al este de Puerto Rico. Los datos se procesaron utilizando espectros de Fourier y espectros de potencia. La tecnica fue validada al compararla con los resultados de cocientes espectrales H/V de registros de sismos debiles y tambien con una modelacion numerica realizada con datos de un ensayo "downhole". Las graficas de los cocientes espectrales H/V fueron divididas en casos y grupos, los cuales dependen de la facilidad para identificar el periodo fundamental pico y amplitudes en frecuencias menores de 1 Hz, respectivamente. Los resultados obtenidos con ambos espectros fueron comparados y se concluye que los mismos se complementan para proveer resultados mas confiables. Se crearon mapas de periodos fundamentales, factores de amplitud, isoperiodos y clasificacion sismica de sitio. Los mapas de isoperiodos fueron realizados en las zonas mas pobladas sobre depositos de suelo. El mapa de periodos fundamentales del suelo mostro buena correlacion con la geologia local. El mapa de clasificacion sismica derivado de periodos de sitio fue comparado con el mapa de clasificacion sismica derivado de barrenos geotecnicos. El mapa de clasificacion obtenido de periodos puede sobreestimar un poco algunas clasificaciones del suelo. Sin embargo, este mapa puede proveer un estimado aproximado de la velocidad de onda de corte promedio del suelo hasta una profundidad de 100 pies (30 metros).

  18. Nonstoichiometry of Al-Zr intermetallic phases

    SciTech Connect

    Radmilovic, V.; Thomas, G.

    1994-06-01

    Nonstoichiometry of metastable cubic {beta}{prime} and equilibrium tetragonal {beta} Al-Zr intermetallic phases of the nominal composition Al{sub 3}Zr in Al-rich alloys has been extensively studied. It is proposed that the ``dark contrast`` of {beta}{prime} core in {beta}{prime}/{sigma}{prime} complex precipitates, in Al-Li-Zr based alloys, is caused by incorporation of Al and Li atoms into the {beta}{prime} phase on Zr sublattice sites, forming nonstoichiometric Al-Zr intermetallic phases, rather than by Li partitioning only. {beta}{prime} particles contain very small amounts of Zr, approximately 5 at.%, much less than the stoichiometric 25 at.% in the Al{sub 3}Zr metastable phase. These particles are, according to simulation of high resolution images, of the Al{sub 3}(Al{sub 0.4}Li{sub 0.4}Zr{sub 0.2}) type. Nonstoichiometric particles of average composition Al{sub 4}Zr and Al{sub 6}Zr are observed also in the binary Al-Zr alloy, even after annealing for several hours at 600{degree}C.

  19. Cyclic oxidation resistance of a reaction milled NiAl-AlN composite

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.; Whittenberger, J. D.

    1990-01-01

    Based upon recent mechanical property tests a NiAl-AlN composite produced by cryomilling has very attractive high temperature strength. This paper focuses on the oxidation resistance of the NiAl-AlN composite at 1473 and 1573 K as compared to that of Ni-47Al-0.15Zr, one of the most oxidation resistant intermetallics. The results of cyclic oxidation tests show that the NiAl-AlN composite has excellent properties although not quite as good as those of Ni-47Al-0.15Zr. The onset of failure of the NiAl-AlN was unique in that it was not accompanied by a change in scale composition from alumina to less protective oxides. Failure in the composite appears to be related to the entrapment of AlN particles within the alumina scale.

  20. Cenomanian-Turonian biostratigraphy of the Jardas Al Abid area, Al Jabal Al Akhdar, northeast Libya

    NASA Astrophysics Data System (ADS)

    El Qot, Gamal M.; Abdulsamad, Esam O.

    2016-09-01

    The Upper Cenomanian-Turonian succession exposed at Jardas al'Abid area consists mainly of carbonates with siliciclastic intercalations. This succession is subdivided lithostratigraphically into: Qasr al'Abid (Late Cenomanian) and Al Baniyah (Late Cenomanian-Coniacian) formations. This sequence is relatively rich in macrofossil assemblages especially bivalves, gastropods, and echinoids with rare ammonites. Based on the first occurrence (FO) and last occurrence (LO) of some index species of these macrofossil groups, an integrated biostratigraphic framework has been constructed. The studied Cenomanian-Turonian sequence is subdivided biostratigraphically into three ammonite biozones; Pseudaspidoceras pseudonodosoides Total Range Zone, Choffaticeras segne Total Range Zone, and Coilopoceras requienianum Total Range Zone. Based on the rest of macrofossil assemblages other than the ammonites, eight biozones were recognized; Mecaster batnensis Total Range Zone, Ceratostreon flabellatum-Neithea dutrugei Acme Zone, Costagyra olisiponensis Acme Zone, Pycnodonte (Phygraea) vesicularis vesiculosa Acme Zone, Mytiloides labiatus Total Range Zone = Mecaster turonensis Acme Zone, Rachiosoma rectilineatum-Curvostrea rouvillei-Tylostoma (T.) globosum Assemblage Zone, Radiolites sp.-Apricardia? matheroni Total Range Zone, and Nerinea requieniana Total Range Zone. Most of the proposed biozones are recorded for the first time from Libya. The integration among these biozones as well as local and inter-regional correlation of the biozones have been discussed. The stage boundaries of the studied stratigraphic intervals are discussed, where the Cenomanian/Turonian boundary is delineated at the last occurrence (LO) of Pseudaspidoceras pseudonodosoides (Choffat), while the Turonian/Coniacian boundary is delineated arbitrary being agree with the LO of the Turonian fauna.

  1. Instantánea del melanoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el melanoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  2. Instantánea del linfoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el linfoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  3. Instantánea del mieloma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el mieloma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  4. Instantánea del sarcoma

    Cancer.gov

    Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el sarcoma; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

  5. Systems Engineering Techniques for ALS Decision Making

    NASA Technical Reports Server (NTRS)

    Rodriquez, Luis F.; Drysdale, Alan E.; Jones, Harry; Levri, Julie A.

    2004-01-01

    The Advanced Life Support (ALS) Metric is the predominant tool for predicting the cost of ALS systems. Metric goals for the ALS Program are daunting, requiring a threefold increase in the ALS Metric by 2010. Confounding the problem, the rate new ALS technologies reach the maturity required for consideration in the ALS Metric and the rate at which new configurations are developed is slow, limiting the search space and potentially giving the perspective of a ALS technology, the ALS Metric may remain elusive. This paper is a sequel to a paper published in the proceedings of the 2003 ICES conference entitled, "Managing to the metric: an approach to optimizing life support costs." The conclusions of that paper state that the largest contributors to the ALS Metric should be targeted by ALS researchers and management for maximum metric reductions. Certainly, these areas potentially offer large potential benefits to future ALS missions; however, the ALS Metric is not the only decision-making tool available to the community. To facilitate decision-making within the ALS community a combination of metrics should be utilized, such as the Equivalent System Mass (ESM)-based ALS metric, but also those available through techniques such as life cycle costing and faithful consideration of the sensitivity of the assumed models and data. Often a lack of data is cited as the reason why these techniques are not considered for utilization. An existing database development effort within the ALS community, known as OPIS, may provide the opportunity to collect the necessary information to enable the proposed systems analyses. A review of these additional analysis techniques is provided, focusing on the data necessary to enable these. The discussion is concluded by proposing how the data may be utilized by analysts in the future.

  6. Opportunity's 'Rub al Khali' Panorama

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR)

    This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.'

    The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth.

    The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers.

    Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars.

    Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can

  7. [Prevalence of American trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B, hepatitis C, human immunodeficiency virus infection, assayed through serological tests among pregnant patients, from 1996 to 1998, at the Regional University Hospital Norte do Paraná].

    PubMed

    Reiche, E M; Morimoto, H K; Farias, G N; Hisatsugu, K R; Geller, L; Gomes, A C; Inoue, H Y; Rodrigues, G; Matsuo, T

    2000-01-01

    In order to evaluate the seroprevalence of the american trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B infection, hepatitis C infection and human immunodeficiency virus infection among pregnant women attended at the Hospital Universitário Regional Norte do Paraná, Londrina State University, Paraná, a retrospective study of the serologic results performed in the prenatal routine during the period of June 1996 to June 1998 was carried out. The rates of seropositivity were as follows: american trypanosomiasis = 0.9%, syphilis = 1.6%, toxoplasmosis = 67% (IgG) and 1.8% (IgM), rubella = 89% (IgG) and 1.2% (IgM), hepatitis B surface antigen = 0.8%, hepatitis C virus = 0.8% and human immunodeficiency virus infection = 0.6%. An association between the increase in the seroprevalence of Chagas' disease and patient age was detected (p=0.006). The results underscore the importance of the serological tests in perinatal care, to prevent both the congenital and perinatally transmitted forms of theses infectious diseases. PMID:11175581

  8. High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces

    PubMed Central

    Herranz, G.; Sánchez, F.; Dix, N.; Scigaj, M.; Fontcuberta, J.

    2012-01-01

    In recent years, striking discoveries have revealed that two-dimensional electron liquids (2DEL) confined at the interface between oxide band-insulators can be engineered to display a high mobility transport. The recognition that only few interfaces appear to suit hosting 2DEL is intriguing and challenges the understanding of these emerging properties not existing in bulk. Indeed, only the neutral TiO2 surface of (001)SrTiO3 has been shown to sustain 2DEL. We show that this restriction can be surpassed: (110) and (111) surfaces of SrTiO3 interfaced with epitaxial LaAlO3 layers, above a critical thickness, display 2DEL transport with mobilities similar to those of (001)SrTiO3. Moreover we show that epitaxial interfaces are not a prerequisite: conducting (110) interfaces with amorphous LaAlO3 and other oxides can also be prepared. These findings open a new perspective both for materials research and for elucidating the ultimate microscopic mechanism of carrier doping. PMID:23091698

  9. Immunomodulatory drugs in AL amyloidosis.

    PubMed

    Jelinek, T; Kufova, Z; Hajek, R

    2016-03-01

    Immunoglobulin light chain amyloidosis (AL amyloidosis) is indeed a rare plasma cell disorder, yet the most common of the systemic amyloidoses. The choice of adequate treatment modality is complicated and depends dominantly on the risk stratification of these fragile patients. Immunomodulatory drugs (IMiDs) are currently used in newly diagnosed patients as well as in salvage therapy in relapsed/refractory patients. IMiDs have a pleiotropic effect on malignant cells and the exact mechanism of their action has been described recently. Thalidomide is the most ancient representative, effective but toxic. Lenalidomide seems to be more effective, nevertheless the toxicity remains high, especially in patients with renal insufficiency. Pomalidomide is the newest IMiD used in this indication with a good balance between efficacy and tolerable toxicity and represents the most promising compound. This review is focused on the evaluation of all three representatives of IMiDs and their roles in the treatment of this malignant disorder. PMID:26806146

  10. Instandhaltungsmanagement als Gestaltungsfeld Ganzheitlicher Produktionssysteme

    NASA Astrophysics Data System (ADS)

    Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo

    Sich kontinuierlich verändernde Rahmenbedingungen, wie beispielsweise eine steigende Variantenvielfalt, verkürzte Produktlebenszyklen sowie Kundenforderungen nach höherer Qualität, kürzeren Lieferzeiten und geringeren Kosten, fordern von produzierenden Unternehmen eine stetige Anpassung der Prozesse, der Organisation und der Strukturen. Seit den 90er Jahren versuchen immer mehr deutsche Unternehmen diesen veränderten Anforderungen mit der Einführung eines Ganzheitlichen Produktionssystems (GPS) zu begegnen. Ganzheitliche Produktionssysteme sind dabei in ihren Grundlagen an das Toyota Produktionssystem angelehnt, vereinigen aber auch weitere Methoden zu einem unternehmensspezifischen Regelwerk. Im Rahmen des langfristigen Trends zu unternehmensindividuellen Produktionssystemen wird sowohl in der Industrie als auch in der Forschung intensiv über das Toyota Produktionssystem, Lean Production, Lean Management und Ganzheitliche Produktionssysteme diskutiert, werden Konzepte zu Implementierung und Betrieb erstellt und die Wirtschaftlichkeit untersucht.

  11. Magnetism of Al-substituted magnetite reduced from Al-hematite

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoxia; Liu, Qingsong; Zhao, Xiang; Roberts, Andrew P.; Heslop, David; Barrón, Vidal; Torrent, José

    2016-06-01

    Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO2 and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.

  12. Reactive Plasma Spraying of Fine Al2O3/AlN Feedstock Powder

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2013-12-01

    Reactive plasma spraying (RPS) is a promising technology for in situ formation of aluminum nitride (AlN) coatings. Recently, AlN-based coatings were fabricated by RPS of alumina (Al2O3) powder in N2/H2 thermal plasma. This study investigated the feasibility of RPS of a fine Al2O3/AlN mixture and the influence of the plasma gases (N2, H2) on the nitriding conversion, and coating microstructure and properties. Thick AlN/Al2O3 coatings with high nitride content were successfully fabricated. The coatings consist of h-AlN, c-AlN, Al5O6N, γ-Al2O3, and a small amount of α-Al2O3. Use of fine particles enhanced the nitriding conversion and the melting tendency by increasing the surface area. Furthermore, the AlN additive improved the AlN content in the coatings. Increasing the N2 gas flow rate improved the nitride content and complete crystal growth to the h-AlN phase, and enhanced the coating thickness. On the other hand, though the H2 gas is required for plasma nitriding of the Al2O3 particles, increasing its flow rate decreased the nitride content and the coating thickness. Remarkable influence of the plasma gases on the coating composition, microstructure, and properties was observed during RPS of the fine particles.

  13. Al/Al-N/AlN compositional gradient film synthesized by ion-beam assisted deposition method

    SciTech Connect

    Amamoto, Yoshiki; Uchiyama, Shingo; Watanabe, Yoshihisa; Nakamura, Yoshikazu

    1997-12-01

    Al/Al-N-AlN compositional gradient thin film was deposited on a Si(100) substrate at room temperature by ion-beam assisted deposition method, with a diminishing ion beam current from 1.4 to 0 mA at increments of 0.3 mA in order to gradually decrease the nitrogen to aluminum ratio at the substrate. The gradual Al and AlN variation in composition was shown by the change of the Al/N atomic ratio analyzed by the energy dispersive X-ray spectroscopy (EDX) and the X-ray photoelectron spectroscopy (XPS) in the cross section of the film. The formation of crystalline Al metal and AlN ceramic layer on the Si substrate was revealed by X-ray diffraction (XRD). The cross sectional image taken by high resolution transmission electron microscope (HRTEM) showed a nano-sized crystalline Al-N ceramic material and the flat interface between the Si substrate and the AlN film.

  14. Accumulation of Al in Root Mucilage of an Al-Resistant and an Al-Sensitive Cultivar of Wheat.

    PubMed Central

    Archambault, D. J.; Zhang, G.; Taylor, G. J.

    1996-01-01

    To estimate rates of Al accumulation within the symplasm, all apoplastic pools of Al need to be eliminated or accounted for. We have developed a revised kinetic protocol that allows us to estimate the contribution of mucilage-bound Al to total, nonexchangeable Al, and to eliminate the mucilage as an apoplastic pool of Al. By comparing the Al content of excised root tips (2 cm) of wheat (Triticum aestivum L.) with and without the removal of the mucilage (using a 10-min wash in 1 M NH4Cl), we found that Al bound to the mucilage accounted for approximately 25 to 35% of Al remaining after desorption in citric acid. The kinetics of Al uptake into mucilage were biphasic, with a rapid phase occurring in the first 30 min of uptake, followed by a linear phase occurring in the remainder of the experimental period (180 min). By adopting a step for removal of mucilage into our existing kinetic protocol, we have been able to isolate a linear phase of uptake with only a slight deviation from linearity in the first 5 min. Although we cannot unambiguously identify this phase of uptake as uptake into the symplasm, we believe this new protocol provides us with the most accurate quantitative estimate of symplastic Al yet available. PMID:12226458

  15. Estimaciones de Prevalencia del VIH por Género y Grupo de Riesgo en Tijuana, México: 2006

    PubMed Central

    Iñiguez-Stevens, Esmeralda; Brouwer, Kimberly C.; Hogg, Robert S.; Patterson, Thomas L.; Lozada, Remedios; Magis-Rodriguez, Carlos; Elder, John P.; Viani, Rolando M.; Strathdee, Steffanie A.

    2010-01-01

    OBJETIVO Estimar la prevalencia del VIH en adultos de 15-49 años de edad en Tijuana, México - en la población general y en subgrupos de riesgo en el 2006. METODOS Se obtuvieron datos demográficos del censo Mexicano del 2005, y la prevalencia del VIH se obtuvo de la literatura. Se construyó un modelo de prevalencia del VIH para la población general y de acuerdo al género. El análisis de sensibilidad consistió en estimar errores estándar del promedio-ponderado de la prevalencia del VIH y tomar derivados parciales con respecto a cada parámetro. RESULTADOS La prevalencia del VIH es 0.54%(N = 4,347) (Rango: 0.22%–0.86%, (N = 1,750–6,944)). Esto sugiere que 0.85%(Rango: 0.39%–1.31%) de los hombres y 0.22%(Rango: 0.04%–0.40%) de las mujeres podrían ser VIH-positivos. Los hombres que tienen sexo con hombres (HSH), las trabajadoras sexuales usuarias de drogas inyectables (MTS-UDI), MTS-noUDI, mujeres UDI, y los hombres UDI contribuyeron las proporciones más elevadas de personas infectadas por el VIH. CONCLUSIONES El número de adultos VIH-positivos entre subgrupos de riesgo en la población de Tijuana es considerable, marcando la necesidad de enforcar las intervenciones de prevención en sus necesidades específicas. El presente modelo estima que hasta 1 en cada 116 adultos podrían ser VIH-positivos. PMID:19685824

  16. Fabrication of Nb/AlO x/Al/AlO x/Nb junctions for voltage standard applications

    NASA Astrophysics Data System (ADS)

    Maezawa, M.; Urano, C.; Kaneko, N.; Kiryu, S.

    2007-10-01

    We present an overdamped superconductor-insulator-normal-insulator-superconductor (SINIS) junction technology for ac voltage standard applications. Modifying our standard Nb-junction process, we developed a simple process for Nb/AlOx/Al/AlOx/Nb-junction circuits. A Josephson arbitrary waveform synthesizer device which consisted of a 100-SINIS-junction array embedded in a 50 Ω coplanar waveguide was fabricated and successfully tested.

  17. Growth and stress-induced transformation of zinc blende AlN layers in Al-AlN-TiN multilayers

    SciTech Connect

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang -Yang; Misra, Amit

    2015-12-18

    We report that AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN.

  18. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers

    PubMed Central

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN. PMID:26681109

  19. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers.

    PubMed

    Li, Nan; Yadav, Satyesh K; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN. PMID:26681109

  20. Desarrollo de un instrumento para medir percepciones sobre el contexto de construccion del conocimiento cientifico de estudiantes universitarios de nuevo ingreso

    NASA Astrophysics Data System (ADS)

    Garcia-Ramirez, Jaime Antonio

    En esta investigacion, se desarrollo un instrumento que permite medir percepciones relacionadas al contexto de constriccion del conocimiento cientifico. Se examinaron instrumentos existentes y se encontro que el VOSTS (Views on science, technology, and society), instrumento desarrollado empiricamente en Canada por Aikenhead, Ryan y Fleming, podia traducirse y validarse en el contexto cultural puertorriqueno. El instrumento es extenso, consta de 113 reactivos, cada uno con una premisa basica relacionada a la tematica ciencia, tecnologia y sociedad y un numero de alternativas relacionadas a la premisa que oscila entre siete y trece. Se delimito su utilizacion a los quince reactivos identificados por los autores como relacionados a la construccion social del conocimiento cientifico. Metodologicamente, se procedio a utilizar el modelo de adaptacion intercultural, que permite que el instrumento desarrollado satisfaga las dimensiones de equivalencia semantica, de contenido, tecnica, de criterio y conceptual, atemperado asi al instrumento original. Se cumplio con este proposito mediante la traduccion de la version original en ingles al espanol y viceversa. Se utilizaron comites para examinar la traduccion y la retro-traduccion del instrumento. Se realizo una prueba piloto con estudiantes universitarios de nuevo ingreso, utilizando el instrumento traducido para asegurar su intelegibilidad. La confiabilidad del instrumento se determino mediante la intervencion de un panel de expertos quienes clasificaron las distintas posiciones dentro de cada reactivo en: realista, con merito e ingenua; se transformaron estas opciones en valores numericos lo que permitio establecer una escala Likert para cada una. Se suministro el instrumento a una muestra de estudiantes universitarios de nuevo ingreso con caracteristicas similares a las de la poblacion puertorriquena en cuanto a ejecucion en las pruebas de aptitud verbal y matematica del College Board. Los resultados de sus contestaciones

  1. Produccion Gaseosa del Cometa Halley: Erupciones Y Fotodisociacion del Radical OH

    NASA Astrophysics Data System (ADS)

    Silva, A. M.; Mirabel, I. F.

    1990-11-01

    RESUMEN:En este trabajo informamos la detecci6n de 20 erupciones en la li'nea de =18cm (1667MHz) del radical OH en el Cometa Halley.Las observaciones incluyen todos los monitoreos existentes y se extienden desde 120 dias antes del perihelio hasta 90 dias despues.Se detectan bruscos crecimientos en el flujo medido,hasta un factor 1O,seguidos por decaimientos lentos asociados con la fotodisociaci6n del OH. Se obtuvieron valores para el tiempo de vida fotoquimico del OH y del H2O basandose en el modelo desarrollado previamente por Silva(1988). Esos tiempos de vida estan de acuerdo con predicciones teoricas y con las observaciones en el Ultravioleta, y los resultados, los que son fuertemente dependientes de la velocidad heliocentrica del Coineta (variando hasta un factor 6), han sido calculados para varios rangos de velocidad entre +28 y -28 km/seg. Key wo'L :

  2. Reply to Vance et al.

    SciTech Connect

    Woon-Chee Yee; Elliott, J.L; Kwon, J.M.; Goodfellow, P.

    1996-07-01

    In our report of a family with a motor and sensory polyneuropathy that was linked to chromosome 3q, we classified this neuropathy as a form of hereditary motor and sensory neuropathy II (HMSN II, also known as {open_quotes}CMT2{close_quotes}). Doubts have been raised by Vance et al. as to whether this neuropathy should be classified as hereditary sensory autonomic neuropathy I (HSAN I) instead of HMSN II. While it is reasonable to raise such doubts, we believe that the neuropathy is best designated as HMSN II for the reasons described below. The group of disorders described as HSAN are characterized by primary or predominant involvement of sensory and autonomic neurons that fail to develop or that undergo atrophy and degeneration. These disorders were extensively reviewed by Dyck and Ohta, who initially described them as the hereditary sensory neuropathies (HSN). It was Dyck who subsequently suggested that these disorders be designated HSAN rather than HSN, because of the presence of autonomic involvement. 8 refs.

  3. Effects of Al Contents on Carburization Behavior and Corrosion Resistance of TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Liao, Cui Jiao; He, Yue Hui; Ming, Xing Zu

    2015-10-01

    TiAl alloys with Al contents of 30.7, 37, 46.5, and 54.2 at.% were carburized. Corrosion resistance of the untreated and the carburized TiAl alloys was comparatively analyzed. The phase and microstructure of the carburized TiAl alloys were studied by x-ray diffraction and scanning electron microscopy, respectively. Electrochemical corrosion behavior of the untreated and the carburized TiAl alloys was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. Experimental results indicate that different Al contents bring about distinct microstructure of the carburized layers. The lower Al content leads to the formation of the thicker binary carbides and the thinner Ti2AlC phase. Additionally, the lower Al content leads to higher corrosion resistance in the untreated and the carburized states.

  4. Orientation relationship of eutectoid FeAl and FeAl2

    PubMed Central

    Scherf, A.; Kauffmann, A.; Kauffmann-Weiss, S.; Scherer, T.; Li, X.; Stein, F.; Heilmaier, M.

    2016-01-01

    Fe–Al alloys in the aluminium range of 55–65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ∊ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [J. Cryst. Growth (1978 ▸), 43, 745] and Hirata et al. [Philos. Mag. Lett. (2008 ▸), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [Acta Cryst. (2010 ▸), C66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a 〈112〉 crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼〈110〉FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. PMID:27047304

  5. Tensile Behavior of Al2o3/feal + B and Al2o3/fecraly Composites

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

    1995-01-01

    The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

  6. A New Phase in ALS Research.

    PubMed

    Chong, P Andrew; Forman-Kay, Julie D

    2016-09-01

    In this issue of Structure, Conicella et al. (2016) present evidence that the low complexity C-terminal region of TDP-43 undergoes liquid-liquid phase separation. ALS-associated mutations alter this phase separation process, providing a possible mechanism for the pathology caused by these TDP-43 mutations. The work is strongly supportive of toxic loss of RNA processing function in ALS. PMID:27602988

  7. Memory deficits and retrieval processes in ALS.

    PubMed

    Mantovan, M C; Baggio, L; Dalla Barba, G; Smith, P; Pegoraro, E; Soraru', G; Bonometto, P; Angelini, C

    2003-05-01

    Subtle neuropsychological deficits have been described in patients affected by amyotrophic lateral sclerosis (ALS) without dementia. Overall, selective impairment in memory function has been reported, but the source of memory impairment in ALS has yet to be defined. We performed neuropsychological screening in 20 ALS patients. Semantic encoding and post-encoding cue effects on the retrieval of word lists were investigated in the ALS patients and normal controls. Severity of memory impairment was correlated to cerebral blood perfusion detected by single photon emission computed tomography (SPECT). ALS patients showed moderate impairments in frontal and memory tests. Short-term memory was normal, while serial position retrieval of word lists with normal recency effect but poor primacy effect showed long-term memory deficit. ALS patients performed better in cued encoding than in cued post-encoding recall condition. In the cued post-encoding condition, the primacy effect in word list recall improved significantly in controls, but not in ALS patients, as compared with both the free recall and cued encoding conditions. SPECT hypoperfusion was observed in frontal and temporal areas in ALS patients. ALS patients showed a long-term memory deficit which did not improve in cued post-encoding condition as it does for controls. We hypothesize abnormal retrieval processes related to frontal lobe dysfunction which entails difficulties in generating stable long-memory traces at encoding. PMID:12752394

  8. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

    NASA Astrophysics Data System (ADS)

    Pstruś, Janusz; Gancarz, Tomasz

    2014-05-01

    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  9. Al-doped ZnO nanocrystals

    NASA Astrophysics Data System (ADS)

    Kadam, Pratibha; Agashe, Chitra; Mahamuni, Shailaja

    2008-11-01

    Al3+-doped ZnO nanocrystals were differently obtained by wet chemical and an electrochemical route. An increase in forbidden gap due to change in crystal size and also due to Al3+ doping in ZnO is critically analyzed. The Moss-Burstein type shift in Al3+-doped ZnO nanocrystals provides an evidence of successful Al3+ doping in ZnO nanocrystals. The possibility of varying the carrier concentration in ZnO nanocrystals is the indirect implication of the present investigations.

  10. Genetics of Familial and Sporadic ALS

    ClinicalTrials.gov

    2016-03-21

    Amyotrophic Lateral Sclerosis (ALS); Familial Amyotrophic Lateral Sclerosis; Amyotrophic Lateral Sclerosis With Frontotemporal Dementia; Lou Gehrig's Disease; Motor Neuron Disease; Primary Lateral Sclerosis

  11. Processing and Mechanical Properties of Directionally Solidified NiAl/NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1994-01-01

    Promising creep strengths were found for a directionally solidified NiAl-NiAlTa alloy when compared to other NiAl based intermetallics. The directionally solidified alloy had an off-eutectic composition that resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of the two phase alloy was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Alloying additions that may improve the room temperature toughness by producing multiphase alloys are discussed.

  12. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jiang, Y; He, Y H; Zou, J; Huang, B; Liu, C

    2008-01-01

    PorousTi Alalloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porousTi Alalloys can have three crystalline phases (i.e., 2-Ti3Al, -TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  13. "Estudio tribologico de aceros para moldes. Aplicacion al moldeo por inyeccion de polibutilentereftalato reforzado con fibra de vidrio"

    NASA Astrophysics Data System (ADS)

    Martinez Mateo, Isidoro Jose

    Mould materials for injection moulding of polymers and polymer-matrix composites represent a relevant industrial economic sector due to the large quantity of pieces and components processed. The material selection for mould manufacturing, its composition and heat treatment, the hardening procedures and machining and finishing processes determine the service performance and life of the mould. In the first part of the present study, the relationship between the hardness and microstructure and the wear resistance of mould steels from large blocks has been studied by pin-on-disc tests, studying the main wear mechanisms. In order to determine the surface damage on mould steels under real injection conditions, different commercial steels have been studied by measuring the variation of surface roughness with the number of injected pieces with different reinforcement percentages and different mould geometries, by using optical profilometry and scanning electron microscopy techniques. It was important to determine the variation of surface roughness of the moulded pieces with the number of injection operations. The materials used were polybutyleneterephthalate pure and reinforced with either 20% or 50% glass fibre. For the different mould designs, the evolution of the glass fibre orientation with injection flow has been determined by image analysis and related to roughness changes and surface damage, both of the composite parts and of the mould steel surface. Finally, the abrasion resistance of the composite parts has been studied by scratch tests as a function of the number of injected parts and of the scratch direction with respect to injection flow and glass fibre orientation. Los materiales para moldes de inyeccion de polimeros y materiales compuestos representan un sector economicamente muy relevante debido al gran aumento del numero de componentes fabricados a partir de materiales polimericos obtenidos mediante moldeo por inyeccion. La seleccion del material para la

  14. Large residuals on geoidal heights determined on the Fagnano Lake, Tierra del Fuego-Argentina

    NASA Astrophysics Data System (ADS)

    Gomez, M. E.; Del Cogliano, D.; Perdomo, R.

    2013-05-01

    A new geoid model was developed in Tierra del Fuego and it was evaluated in the area of Fagnano Lake. The model was developed by means of the Equivalent Source Technique combining gravity data, levelling information measured on the province and observations of a GPS buoy on the Fagnano Lake. Those GPS buoy measurements provide information of the mean lake level surface (Del Cogliano et al., 2007). A cross validation process was realized in order to evaluate the model on the lake. What allowed determining a 6 cm geoid in the area of Fagnano Lake. Also, an evaluation of the EGM2008 (Pavlis et al., 2008) was made on the lake. Its behaviour was compared to that observed on the levelling lines. Differences of several decimetres were found when EGM2008 undulations were compared to observed geoid undulations in the lake area. In the regions where EGM2008 has included real gravimetric observations, differences between model and observations were only of a few centimetres. Such model has the particularity that includes fill-in gravity in that region. The above mentioned evaluation derived in an analysis of the effect that not representative gravity information could have on the estimation of geoid undulations in high mountainous regions. We found that this effect could be significant if there is no real information in the computing area (Gomez et al, 2012).

  15. Inventario mundial de la calidad del carbon mineral (WoCQI) [The world coal quality inventory (WoCQI)

    USGS Publications Warehouse

    Finkelman, R.B.; Lovern, V.S.

    2001-01-01

    Los oficiales encargados de la politica comercial de cada pais requieren informacion clara y precisa sobre el recurso del carbon mineral, particularmente sobre sus propiedades y caracteristicas, para tomar decisiones bien fundamentadas con respecto al mejor uso de los recursos naturales, necesidades de importacion y oportunidades de exportacion, objetivos de politica interna y externa, oportunidades de transferencia tecnologica, posibilidades de inversion externa, estudios ambientales y de salud, y asuntos relacionados con el uso de productos secundarios y su disposicion.

  16. Response to Signorovitch et al.

    PubMed

    Flot, Jean-François; Debortoli, Nicolas; Hallet, Bernard; Van Doninck, Karine

    2016-08-22

    Signorovitch et al.[1] comment that an Oenothera-like meiosis [2] could produce a pattern similar to what we observed in our study of natural isolates of the bdelloid rotifer Adineta vaga, which we attributed to horizontal gene transfers (HGTs) [3]. Indeed, our HGT hypothesis appears at first sight difficult to conciliate with their observation of a congruent pattern of allele sharing at four large loci possibly located on different chromosomes [4]. However, one might imagine conditions under which massive horizontal gene transfer between bdelloid individuals could produce such a pattern, notably if the individuals involved had previously lost most of their heterozygosity because of their exposure to frequent desiccation (which produces DNA double-strand breaks [5]). In the published A. vaga genome the loss of heterozygosity due to large-scale gene conversion events or break-induced replication covers only about 10% of the genome [6], but this percentage may be much higher in environmental isolates that often experience dessication. Besides, if an Oenothera-like mode of meiosis occurs in bdelloids frequently enough to be detected in a single sampling of 29 individuals (as in [4]), one would expect males and meiosis to be observed at least occasionally, and instances of congruent allele sharing across loci should turn up frequently in genetic surveys. This was not the case in [3]: among the 82 A. vaga individuals sequenced for four nuclear markers, no trio of individuals presented congruent patterns of shared sequences at different loci. For these reasons, and in the absence of any direct evidence for an Oenothera-like meiosis in bdelloids, we still consider inter-bdelloid HGTs a more parsimonious explanation for our results. PMID:27554651

  17. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    NASA Astrophysics Data System (ADS)

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-07-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits.

  18. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    PubMed Central

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  19. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions.

    PubMed

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  20. Gonadal dysgenesis in del (18p) syndrome

    SciTech Connect

    Telvi, L.; Ion, A.; Fouquet, F.

    1995-07-17

    We report on a girl with syndromal gonadal dysgenesis and a de novo del (18p). Genetic factors controlling gonadal development are located not only on the X chromosome, but also on autosomes. The present case suggests that one of these genes is situated on 18p. We conclude that patients with del (18p) syndrome should be evaluated for gonadal dysgenesis. 16 refs., 3 figs.

  1. Evaluation of surrogate markers for human immunodeficiency virus infection among blood donors at the blood bank of "Hospital Universitário Regional Norte do Paraná", Londrina, PR, Brazil.

    PubMed

    Reiche, Edna Maria Vissoci; Vogler, Ingridt Hildegard; Morimoto, Helena Kaminami; Bortoliero, André Luis; Matsuo, Tiemi; Yuahasi, Kátia Kioko; Cancian, Sanderson Júnior; Koguichi, Roberto Setsuo

    2003-01-01

    This study evaluated the usefulness of the anti-HBc, hepatitis C virus antibodies (anti-HCV), human T cell lymphotropic virus I and II antibodies (anti-HTLV I/II), serologic tests for syphilis, and surface antigen of hepatitis B virus (HBsAg) as surrogate markers for the risk for HIV infection in 80,284 serum samples from blood donors from the Blood Bank of "Hospital Universitário Regional Norte do Paraná", Londrina, Paraná State, Brazil, analyzed from July 1994 to April 2001. Among 39 blood donors with positive serology for HIV, 12 (30.8%) were anti-HBc positive, 10 (25.6%) for anti-HCV, 1 (2.6%) for anti-HTLV I/I, 1 (2.6%) was positive for syphilis, and 1 (2.6%) for HBsAg. Among the donors with negative serology for HIV, these markers were detected in 8,407 (10.5%), 441 (0.5%), 189 (0.2%), 464 (0.6%), and 473 (0.6%) samples, respectively. The difference was statistically significant (p < 0.001) for anti-HBc and anti-HCV. Although the predictive positive values for these surrogate markers were low for HIV infection, the results confirmed the anti-HBc and anti-HCV as useful surrogate markers for HIV infection thus reinforcing the maintenance of them in the screening for blood donors contributing to the prevention of the small number of cases in which HIV is still transmitted by transfusion. PMID:12751318

  2. Durability Assessment of TiAl Alloys

    NASA Technical Reports Server (NTRS)

    Draper, Susan L.; Lerch, Bradley A.

    2008-01-01

    The durability of TiAl is a prime concern for the implementation of TiAl into aerospace engines. Two durability issues, the effect of high temperature exposure on mechanical properties and impact resistance, have been investigated and the results are summarized in this paper. Exposure to elevated temperatures has been shown to be detrimental to the room temperature ductility of gamma alloys with the most likely mechanisms being the ingress of interstitials from the surface. Fluorine ion implantation has been shown to improve the oxidation resistance of gamma alloys, and ideally it could also improve the environmental embrittlement of high Nb content TiAl alloys. The effect of F ion implantation on the surface oxidation and embrittlement of a third generation, high Nb content TiAl alloy (Ti-45Al-5Nb-B-C) were investigated. Additionally, the ballistic impact resistance of a variety of gamma alloys, including Ti-48Al-2Cr- 2Nb, Ti-47Al-2Cr-2Nb, ABB-2, ABB-23, NCG359E, 95A and Ti-45Al-5Nb-B-C was accessed. Differences in the ballistic impact properties of the various alloys will be discussed, particularly with respect to their manufacturing process, microstructure, and tensile properties.

  3. 76 FR 18783 - United States et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... Antitrust Division United States et al. v. Dean Foods Company; Proposed Final Judgment, Stipulation and... of America, et al. v. Dean Foods Company, Civil Action No. 2:10-cv-00059 (JPS). On January 22, 2010, the United States and its co-plaintiffs filed a Complaint alleging that Dean Foods...

  4. Diana Al-Hadid: Identity and Heritage

    ERIC Educational Resources Information Center

    Jungerberg, Tom; Smith, Anna; Borsh, Colleen

    2012-01-01

    Diana Al-Hadid's sculptures reflect the many locations, cultures, histories, and mythologies that have shaped her as an artist. In large-scale works which have the appearance of architectural ruins, Al-Hadid employs imagery drawn from many diverse interests including science and technology, history, and literature. She also incorporates images and…

  5. 75 FR 62858 - United States, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-13

    ... Antitrust Division United States, et al. v. American Express Company, et al.; Proposed Final Judgment and... been filed with the United States District Court for the Eastern District of New York in United States..., 2010, the United States and seven States filed a Complaint alleging that certain rules, policies,...

  6. Energetics of Al13 Keggin cluster compounds

    PubMed Central

    Armstrong, Christopher R.; Casey, William H.; Navrotsky, Alexandra

    2011-01-01

    The ϵ-Al13 Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ϵ-Keggin clusters, Al13 selenate, (Na(AlO4)Al12(OH)24(SeO4)4•12H2O) and Al13 sulfate, (NaAlO4Al12(OH)24(SO4)4•12H2O). The measured enthalpies of solution, ΔHsol, at 28 °C in 5 N HCl for the ε-Al13 selenate and sulfate are −924.57 (± 3.83) and −944.30 ( ± 5.66) kJ·mol-1, respectively. The enthalpies of formation from the elements, ΔHf,el, for Al13 selenate and sulfate are −19,656.35 ( ± 67.30) kJ·mol-1, and −20,892.39 ( ± 70.01) kJ·mol-1, respectively. In addition, ΔHf,el for sodium selenate decahydrate was calculated using data from high temperature oxide melt solution calorimetry measurements: −4,006.39 ( ± 11.91) kJ·mol-1. The formation of both ε-Al13 Keggin cluster compounds is exothermic from oxide-based components but energetically unfavorable with respect to a gibbsite-based assemblage. To understand the relative affinity of the ϵ-Keggin clusters for selenate and sulfate, the enthalpy associated with two S-Se exchange reactions was calculated. In the solid state, selenium is favored in the Al13 compound relative to the binary chalcogenate, while in 5 N HCl, sulfur is energetically favored in the cluster compound compared to the aqueous solution. This contribution represents the first thermodynamic study of ε-Al13 cluster compounds and establishes a method for other such molecules, including the substituted versions that have been created for kinetic studies. Underscoring the importance of ε-Al13 clusters in natural and anthropogenic systems, these data provide conclusive thermodynamic evidence that the Al13 Keggin cluster is a crucial intermediate species in the formation pathway from aqueous aluminum monomers to aluminum hydroxide precipitates. PMID:21852572

  7. Characteristics of heat resistant alloys Ti10Nb45Al and Ti18Nb48Al

    SciTech Connect

    Weijun Zhang; Guoliang Chen; Yandong Wang; Zuqing Sun )

    1993-05-01

    Based on a systematic study of the ternary Ti-Nb-Al system, two attractive heat resistant alloys, Ti10Nb45Al and Ti18Nb48Al, were developed, and the characteristics of these alloys were discussed: (1) After annealing at 1,200 C for 240 h and furnace cooling to room temperature, the Ti10Nb45Al alloy exhibits an [alpha][sub 2] + [gamma] lamellar microstructure, and the Ti18Nb48Al alloy shows a plate-like structure consisting of [alpha][sub 2], [gamma] and [gamma][sub 1] phases. (2) The specific strengths of Ti10Nb45Al and Ti18Nb48Al are much higher than TiAl and superalloys in the temperature range of 800 [approximately] 1,100 C. The compressive yield strengths of these alloys are on the order of 700 MPa at 800 C and 350 MPa at 1,100 C. The density of these alloys is about 4.3 g/cm[sup 3]. (3) The annealed Ti10Nb45Al and Ti18Nb48Al exhibit some ductility at room temperature, with the compressive elongation on the order of 12% and the fracture toughness as high as 16 MPa[radical]m. The ductile-brittle transformation temperatures for Ti10Nb45Al and Ti18Nb48Al are 650 C and 750 C, respectively. (4) The parabolic constant K[sub p] for oxidation of Ti10Nb45Al and Ti18Nb48Al are 0.88 and 0.29 mg[sup 2]cm[sup [minus]4]h[sup [minus]1] respectively, which are two orders of magnitude lower than that of TiAl and Ti[sub 3]Al alloys.

  8. Nucleation and Precipitation Strengthening in Dilute Al-Ti and Al-Zr Alloys

    NASA Astrophysics Data System (ADS)

    Knipling, Keith E.; Dunand, David C.; Seidman, David N.

    2007-10-01

    Two conventionally solidified Al-0.2Ti alloys (with 0.18 and 0.22 at. pct Ti) exhibit no hardening after aging up to 3200 hours at 375 °C or 425 °C. This is due to the absence of Al3Ti precipitation, as confirmed by electron microscopy and electrical conductivity measurements. By contrast, an Al-0.2Zr alloy (with 0.19 at. pct Zr) displays strong age hardening at both temperatures due to precipitation of Al3Zr (L12) within Zr-enriched dendritic regions. This discrepancy between the two alloys is explained within the context of the equilibrium phase diagrams: (1) the disparity in solid and liquid solubilities of Ti in α-Al is much greater than that of Zr in α-Al; and (2) the relatively small liquid solubility of Ti in α-Al limits the amount of solute retained in solid solution during solidification, while the comparatively high solid solubility reduces the supersaturation effecting precipitation during post-solidification aging. The lattice parameter mismatch of Al3Ti (L12) with α-Al is also larger than that of Al3Zr (L12), further hindering nucleation of Al3Ti. Classical nucleation theory indicates that the minimum solute supersaturation required to overcome the elastic strain energy of Al3Ti nuclei cannot be obtained during conventional solidification of Al-Ti alloys (unlike for Al-Zr alloys), thus explaining the absence of Al3Ti precipitation and the presence of Al3Zr precipitation.

  9. High temperature creep behaviour of Al-rich Ti-Al alloys

    NASA Astrophysics Data System (ADS)

    Sturm, D.; Heilmaier, M.; Saage, H.; Aguilar, J.; Schmitz, G. J.; Drevermann, A.; Palm, M.; Stein, F.; Engberding, N.; Kelm, K.; Irsen, S.

    2010-07-01

    Compared to Ti-rich γ-TiAl-based alloys Al-rich Ti-Al alloys offer an additional reduction of in density and a better oxidation resistance which are both due to the increased Al content. Polycrystalline material was manufactured by centrifugal casting. Microstructural characterization was carried out employing light-optical, scanning and transmission electron microscopy and XRD analyses. The high temperature creep of two binary alloys, namely Al60Ti40 and Al62Ti38 was comparatively assessed with compression tests at constant true stress in a temperature range between 1173 and 1323 K in air. The alloys were tested in the cast condition (containing various amounts of the metastable phases Al5Ti3 and h-Al2Ti) and after annealing at 1223 K for 200 h which produced (thermodynamically stable) lamellar γ-TiAl + r-Al2Ti microstructures. In general, already the as-cast alloys exhibit a reasonable creep resistance at 1173 K. Compared with Al60Ti40, both, the as-cast and the annealed Al62Ti38 alloy exhibit better creep resistance up to 1323 K which can be rationalized by the reduced lamella spacing. The assessment of creep tests conducted at identical stress levels and varying temperatures yielded apparent activation energies for creep of Q = 430 kJ/mol for the annealed Al60Ti40 alloy and of Q = 383 kJ/mol for the annealed Al62Ti38 material. The latter coincides well with that of Al diffusion in γ-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

  10. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  11. NiAl alloys for structural uses

    NASA Technical Reports Server (NTRS)

    Koss, D. A.

    1991-01-01

    Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the

  12. Al-Akhawayni's description of pulmonary circulation.

    PubMed

    Yarmohammadi, Hassan; Dalfardi, Behnam; Rezaian, Jafar; Ghanizadeh, Ahmad

    2013-10-01

    Since antiquity, heart function and the mechanism of blood circulation within the human body have been the focus of attention of scientists from different parts of the world. Over the passage of time, the theories and works of these scientists have resulted in the achievement of today's knowledge of circulation. The medieval Persian scholar, Al-Akhawayni Bukhari (?-983AD), is among the physicians who investigated both the anatomy and the physiology of the human body. Al-Akhawayni describes the mechanism of pulmonary circulation in his only extant book, "Hidayat al-Muta`llemin fi al-Tibb" (A Scholar's Guide to Medicine) with which he made a contribution to the development of knowledge regarding this mechanism in the medicine of the Islamic world. In this paper, Al-Akhawayni's viewpoints on anatomy and the function of the heart, its related vessels, and also pulmonary circulation will be briefly discussed. PMID:23890868

  13. Opportunities for improving therapy development in ALS.

    PubMed

    Bruijn, Lucie; Cudkowicz, Merit

    2014-06-01

    In May 2013, The ALS Association and The Northeast ALS Consortium (NEALS) convened a meeting of stakeholders for a round-table discussion of ways to improve therapy development in ALS. The following overview summarizes issues raised and potential new directions discussed at the meeting. We recommend that future phase II clinical trials in ALS proceed when the proposed treatment is directed at targets that are likely to be involved in ALS pathogenesis in a defined subgroup of patients, and be accompanied by one or more biomarkers to track both clinical progression and pharmacodynamic engagement of the target. Innovations in trial structure and design, and greater involvement of patient advocates, may also improve trials. PMID:24472060

  14. AL(0) in municipal waste incinerator ash

    NASA Astrophysics Data System (ADS)

    Stipp, S. L.; Ronsbo, J. G.; Zunic, T. B.; Christensen, T. H.

    2003-04-01

    Disposal of municipal waste is a challenge to society. Waste volume is substantially decreased by incineration but residual ash usually contains a number of toxic components which must be immobilised to insure environmental protection. One element, chromium, is mobile and toxic in its oxidised state as Cr(VI) but it can be reduced to Cr(III) and immobilised. Reduction can be promoted by ash treatment with Fe(0) or Fe(II), but recent evidence shows that at least some Cr(VI) is reduced spontaneously in the ash. Aspects of ash behaviour suggest metallic aluminium as the reducing agent, but no direct evidence of Al(0) has been found until now. We examined filter ash from an energy-producing, municipal-waste incinerator (Vest-forbrænding) near Copenhagen. X-ray diffraction (XRD) identified expected salts of Na, K and Ca such as halite, sylvite, calcite, anhydrite and gypsum as well as quartz, feldspar and some hematite. Wave-dispersive electron microprobe produced elemen-tal maps of the ash; Al-rich areas were analysed quantitatively by comparison with standards. We identified metallic Al particles, averaging 50 to 100 micrometers in di-ameter, often with a fractured, glassy border of aluminum oxide. The particles were porous, explaining fast Cr(VI) reduction and they contained thin exsolution lamellae of Al-alloys of Pb and Cu or Mn, Fe and Ag, which provide clues of the Al(0) origin in the waste. Sometimes Al(0) occurred inside glassy globes of Al2O3. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) proved that surface Al concentrations on ash particles were below detection, confirming reactivity of the Al(0) bulk. The persistence of reduced Al through the highly oxidising combustion procedure comes as a surprise and is a benefit in the immobilisation of Cr(VI) from municipal-waste incineration residues.

  15. Spatially Controlled Fe Isotope Variations at Torres del Paine

    NASA Astrophysics Data System (ADS)

    Gajos, N.; Lundstrom, C.

    2013-12-01

    experimental results [1] fractional crystallization involving magnetite-melt fractionation should produce isotopically light melts, contrary to the isotopic signature seen in Torres. On the other hand, magnetite-fluid experiments show that late-stage fluid exsolution in plutons has the potential to produce isotopic signatures similar to Torres del Paine [1]. However, the amount of fractionation is highly dependent on the amount of Fe saturated in the fluid. The fractionation trend of Fe is also consistent with thermal migration experiments [3]. The spatial partitioning of heavy Fe at the felsic margins of the pluton and light Fe at the mafic base of the pluton is also consistent with this mechanism. The co-variation with other non-traditional stable isotope systems provides a crucial test to assessing the effects of thermal migration. [1] Belinker et al. (2012) AGU Meeting Abstract. [2] Heimann A. et al. (2008) GCA 72, 4379-4396.[3] Lundstrom (2009) GCA 73, 5709-5729.

  16. Intertextual Sexual Politics: Illness and Desire in Enrique Gomez Carrillo's "Del amor", "del dolor y del vicio" and Aurora Caceres's "La rosa muerta"

    ERIC Educational Resources Information Center

    LaGreca, Nancy

    2012-01-01

    This study explores the intertextuality between Aurora Caceres's "La rosa muerta" (1914) and the novel "Del amor, del dolor y del vicio" (1898) by her ex-husband, Enrique Gomez Carrillo. Caceres strategically mentions Gomez Carrillo's novel in "La rosa muerta" to invite a reading of her work in dialogue with his. Both narratives follow the sexual…

  17. Japanese version of the ALS-FTD-Questionnaire (ALS-FTD-Q-J).

    PubMed

    Watanabe, Yasuhiro; Beeldman, Emma; Raaphorst, Joost; Izumi, Yuishin; Yoshino, Hiide; Masuda, Michihito; Atsuta, Naoki; Ito, Satoru; Adachi, Tadashi; Adachi, Yoshiki; Yokota, Osamu; Oda, Masaya; Hanashima, Ritsuko; Ogino, Mieko; Ichikawa, Hiroo; Hasegawa, Kazuko; Kimura, Hideki; Shimizu, Toshio; Aiba, Ikuko; Yabe, Hayato; Kanba, Makoto; Kusumi, Kimiyoshi; Aoki, Tetsuya; Hiroe, Yu; Watanabe, Hirohisa; Nishiyama, Kazutoshi; Nomoto, Masahiro; Sobue, Gen; Nakashima, Kenji

    2016-08-15

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share common clinical, genetic and neuropathological features. Some ALS patients have behavioral/personality changes, which could result in significant obstacles in the care provided by family members and caregivers. An easy screening tool would contribute greatly to the evaluation of these symptoms. We translated the ALS-FTD-Questionnaire, developed in the Netherlands, into Japanese (ALS-FTD-Q-J) and examined the clinimetric properties (internal consistency, construct and clinical validity). Patients with ALS and/or behavioral variant FTD (bvFTD) were evaluated alongside healthy controls in this multicenter study. All ALS patients, regardless of bvFTD status, were further evaluated by the frontal behavioral inventory (FBI) and for frontal/executive function, cognition, anxiety/depression, and motor functions. Data from 146 subjects were analyzed: ALS (92), ALS-bvFTD (6), bvFTD (16), and healthy controls (32). The internal consistency of the ALS-FTD-Q-J was good (Cronbach α=0.92). The ALS-FTD-Q-J showed construct validity as it exhibited a high correlation with the FBI (r=0.79). However, correlations were moderate with anxiety/depression and low with cognitive scales, in contrast to the original report, i.e. a moderate correlation with cognition and a low correlation with anxiety/depression. The ALS-FTD-Q-J discriminated ALS patients from (ALS-)bvFTD patients and controls. Thus, the ALS-FTD-Q-J is useful for evaluating Japanese ALS/FTD patients. PMID:27423564

  18. Atomistic Modeling of RuAl and (RuNi) Al Alloys

    NASA Technical Reports Server (NTRS)

    Gargano, Pablo; Mosca, Hugo; Bozzolo, Guillermo; Noebe, Ronald D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Atomistic modeling of RuAl and RuAlNi alloys, using the BFS (Bozzolo-Ferrante-Smith) method for alloys is performed. The lattice parameter and energy of formation of B2 RuAl as a function of stoichiometry and the lattice parameter of (Ru(sub 50-x)Ni(sub x)Al(sub 50)) alloys as a function of Ni concentration are computed. BFS based Monte Carlo simulations indicate that compositions close to Ru25Ni25Al50 are single phase with no obvious evidence of a miscibility gap and separation of the individual B2 phases.

  19. Effects of hydrogen absorption in TbNiAl and UNiAl

    SciTech Connect

    Bordallo, H.N.; Nakotte, H.; Schultz, A.; Kolomiets, A.V.; Havela, L.; Andreev, A.V.

    1998-12-31

    Although hydrides of intermetallic compounds are used extensively as hydrogen-storage media, little is known about the exact nature of metal-hydrogen interactions. However, this knowledge is of essential importance for the understanding of thermodynamics and other properties. Hydrides (deuterides) of TbNiAl and UNiAl have been widely studied because of drastic increase of magnetic ordering temperature under hydrogenation. Here the authors report neutron-diffraction results of the three deuterides, TbNiAlD{sub 1.28}, TbNiAlD{sub 0.8}a nd UNiAlD{sub 2.23}.

  20. A new discontinuously reinforced aluminum MMC: Al+AlB{sub 2} flakes

    SciTech Connect

    HALL,AARON C.; ECONOMY,J.

    2000-06-08

    Development of a novel metal matrix composite based on the Al-B alloy system has been undertaken. Preparation of this discontinuously reinforced material is based on the precipitation of high aspect ratio AlB{sub 2} from an Al-B alloy. This paper describes a number of efforts forced on preparing high volume fractions (> 30 v%) of AlB{sub 2} in aluminum. New insights into the behavior of the Al-B alloys system allowed this effort to be successful.

  1. Orthorhombic aluminium oxyfluoride, AlOF.

    PubMed

    Vasiliev, Alexander D; Melnikova, Svetlana V; Isaenko, Lyudmila I

    2009-04-01

    Crystals of the title compound were extracted from the bulk of grown SrAlF(5) crystals as unexpected inclusions that were identified as the long sought after aluminium oxyfluoride. The structure of AlOF is built up from tetrahedral and octahedral polyhedra. Each tetrahedron is bisected by a mirror plane, with the Al atom and two vertex anions in the plane. All tetrahedral vertices are positions of competing oxide and fluoride ions and are shared with octahedra. These shared vertices belong to two octahedral edges which join the octahedra to form infinite zigzag chains. The chains are strung along twofold screw axes that run parallel to the unit-cell b axis. The remaining two octahedral vertices are occupied only by fluoride ions. A small deficiency in the occupation of the octahedral Al position was suggested by the refinement. However, the stoichiometry of the compound is AlOF within experimental uncertainty. The Al-F(O) distances are separated into three groups with average values of 1.652 (3) (tetrahedra), 1.800 (2) (octahedra) and 1.894 (2) A (octahedra). This structure differs widely from the reported tetragonal phase Al(1-x)O(1-3x)F(1+3x) (x = 0.0886) [Kutoglu (1992). Z. Kristallogr. 199, 197-201], which consists solely of octahedral structural units. PMID:19346595

  2. Electrical conductivity of Al-bearing bridgmanite

    NASA Astrophysics Data System (ADS)

    Yoshino, T.; Kamada, S.; Ohtani, E.; Hirao, N.

    2015-12-01

    Electrical conductivity measurements of bridgmanite with various Al contents and constant Mg# 90 at room temperature up to 2000 K and 26-28 GPa were performed in Kawai-type multianvil apparatus using impedance spectroscopic analyses. The incorporation of Al into bridgmanite significantly raises the electrical conductivity but it is small conductivity variation with respect to the amount of Al. Synchrotron Mössbauer spectroscopy of recovered samples showed a significant amount of ferric iron in aluminous bridgmanite. The mobility of charge carriers in bridgmanite was calculated from the conductivity and Fe3+/ΣFe. A relation between the logarithm of electrical conductivity and reciprocal temperature is consistent with Fe2+-Fe3+ electron hopping (small polaron) as the dominant conduction mechanism at low temperatures (< 1400 K) and ionic conduction at high temperatures (> 1600 K). Taking various conduction mechanisms into account, we develop an electrical conductivity model for aluminous bridgmanite as a function of Al and Fe content. This conductivity model suggests that the electrical conductivity of aluminous bridgmanite has a maximum at around 0.13 Al per formula unit, and further increase of Al in bridgmanite reduces the conductivity. The conductivity increase observed in the uppermost lower mantle by electromagnetic studies can be explained by increases of Fe and Na content in combination with substitution of Al into bridgmanite with increasing pressure due to the gradual decomposition of majorite garnet.

  3. Comparative study on interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor heterostructures with Al2O3, AlN, and Al2O3/AlN laminated dielectrics

    NASA Astrophysics Data System (ADS)

    Zhu, Jie-Jie; Ma, Xiao-Hua; Chen, Wei-Wei; Hou, Bin; Xie, Yong; Hao, Yue

    2016-05-01

    In this paper, the interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor (MIS) heterostructures with AlN, Al2O3, and Al2O3/AlN laminated dielectrics were studied. In situ plasma pretreatment resulted negligible interface trap states and voltage hysteresis. The fixed charge density at Al2O3/AlN (or Al2O3/barrier) interface was estimated to be 1.66 × 1013 cm-2 by using flat-band voltage shift, and the oxide bulk charge concentration was 2.86 × 1017 cm-3. The interface charge density at other interfaces were at the order of 1011 cm-2. Simulation results using the above charge density/concentration indicated that Al2O3/AlN interface fixed charges dominated the dielectric-related voltage shift in AlGaN/GaN MIS heterostructures, which caused a large voltage shift of -3 V with 10 nm Al2O3 thickness, while the flat-band voltage variety resulting from other types of charges was within 0.1 V.

  4. Arsenate uptake by Al nanoclusters and other Al-based sorbents during water treatment.

    PubMed

    Mertens, Jasmin; Rose, Jérôme; Wehrli, Bernhard; Furrer, Gerhard

    2016-01-01

    In many parts of the world, arsenic from geogenic and anthropogenic sources deteriorates the quality of drinking water resources. Effective methods of arsenic removal include adsorption and coagulation with iron- and aluminum-based materials, of which polyaluminum chloride is widely employed as coagulant in water treatment due to its low cost and high efficiency. We compared the arsenic uptake capacity and the arsenic bonding sites of different Al-based sorbents, including Al nanoclusters, polyaluminum chloride, polyaluminum granulate, and gibbsite. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that As(V) forms bidentate-binuclear complexes in interaction with all Al-based removal agents. The octahedral configuration of nanoclusters and the distribution of sorption sites remain the same in all types of removal agents consisting of nano-scale Al oxyhydroxide particles. The obtained distances for As(V)-O and As(V)-Al agreed with previously published data and were found to be 1.69 ± 0.02 Å and 3.17-3.21 Å, respectively. Our study suggests that As(V) binds to Al nanoclusters as strongly as to Al oxide surfaces. The As sorption capacity of Al nanoclusters was found to be very similar to that of Al clusters in a polyaluminum chloride. The most efficient Al-based sorbents for arsenic removal were Al nanoclusters, followed by polyaluminum granulate. PMID:26613179

  5. Hybrid Al + Al3Ni metallic foams synthesized in situ via laser engineered net shaping

    NASA Astrophysics Data System (ADS)

    Zheng, Baolong; Li, Ying; Smugeresky, John E.; Zhou, Yizhang; Baker, Dean; Lavernia, Enrique J.

    2011-09-01

    A hybrid, Al + Al3Ni metallic foam was synthesized in situ via laser engineered net shaping (LENS®) of Ni-coated 6061 Al powder in the absence of a foaming agent. During LENS® processing, the Ni coating reacted with the Al matrix, resulting in the simultaneous formation of a fine dispersion of Al3Ni, and a high volume fraction of porosity. As a reinforcement phase, the intermetallic compound formed particles with a size range of 1-5 µm and a volume fraction of 63%, with accompanying 35-300 µm pores with a 60% volume fraction. The microstructure of the as-deposited Al + Al3Ni composite foams was characterized using SEM, EDS, XRD and TEM/HRTEM techniques. The evolution of the microstructure was analyzed on the basis of the thermal field present during deposition, paying particular attention to the thermodynamics of the Al3Ni intermetallic compound formation as well as discussing the mechanisms that may be responsible for the observed porosity. The mechanical behavior of the as-deposited material was characterized using compression and microhardness testing, indicating that the yield strength and hardness are 190 MPa and 320 HV, respectively, which represents an increase of over three times higher than that of annealed Al6061, or similar to heat-treated Al6061 fully dense matrix, and much higher than those of traditional Al alloy foams, and with a low density of 1.64 g/m3.

  6. Optical characterization of Al- and N-polar AlN waveguides for integrated optics

    NASA Astrophysics Data System (ADS)

    Rigler, Martin; Buh, Jože; Hoffmann, Marc P.; Kirste, Ronny; Bobea, Milena; Mita, Seiji; Gerhold, Michael D.; Collazo, Ramon; Sitar, Zlatko; Zgonik, Marko

    2015-04-01

    Dispersion of the extraordinary and ordinary refractive indices of Al- and N-polar AlN waveguides is measured by multiple angle-of-incidence and spectroscopic ellipsometry techniques. The polarity-controlled AlN layers are grown by metal-organic chemical vapor deposition on (0001)-sapphire substrates. Taking into consideration the different surface morphologies of the Al- and N-polar AlN waveguides, we propose two optical models to describe the measured ellipsometry data. The results indicate that there is no difference between the refractive indices of the AlN grown in opposite directions, which confirms the potential of the AlN lateral polar structures for use in nonlinear optical applications based on quasi phase matching.

  7. A Rechargeable Al/S Battery with an Ionic-Liquid Electrolyte.

    PubMed

    Gao, Tao; Li, Xiaogang; Wang, Xiwen; Hu, Junkai; Han, Fudong; Fan, Xiulin; Suo, Liumin; Pearse, Alex J; Lee, Sang Bok; Rubloff, Gary W; Gaskell, Karen J; Noked, Malachi; Wang, Chunsheng

    2016-08-16

    Aluminum metal is a promising anode material for next generation rechargeable batteries owing to its abundance, potentially dendrite-free deposition, and high capacity. The rechargeable aluminum/sulfur (Al/S) battery is of great interest owing to its high energy density (1340 Wh kg(-1) ) and low cost. However, Al/S chemistry suffers poor reversibility owing to the difficulty of oxidizing AlSx . Herein, we demonstrate the first reversible Al/S battery in ionic-liquid electrolyte with an activated carbon cloth/sulfur composite cathode. Electrochemical, spectroscopic, and microscopic results suggest that sulfur undergoes a solid-state conversion reaction in the electrolyte. Kinetics analysis identifies that the slow solid-state sulfur conversion reaction causes large voltage hysteresis and limits the energy efficiency of the system. PMID:27417442

  8. Oxidation of Al2O3 continuous fiber-reinforced/NiAl composites

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Nesbitt, J. A.; Noebe, R. D.; Bowman, R. R.

    1992-01-01

    The 1200 C and 1300 C isothermal and cyclic oxidation behavior of Al2O3 continuous fiber-reinforced/NiAl composites were studied. Oxidation resulted in formation of Al2O3 external scales in a similar manner as scales formed on monolithic NiAl. The isothermal oxidation of an Al2O3/NiAl composite resulted in oxidation of the matrix along the fiber/matrix interface near the fiber ends. This oxide acted as a wedge between the fiber and the matrix, and, under cyclic oxidation conditions, led to further oxidation along the fiber lengths and eventual cracking of the composite. The oxidation behavior of composites in which the Al2O3 fibers were sputter coated with nickel prior to processing was much more severe. This was attributed to open channels around the fibers which formed during processing, most likely as a result of the diffusion of the nickel coating into the matrix.

  9. High performance AlGaN/GaN HEMTs with AlN/SiNx passivation

    NASA Astrophysics Data System (ADS)

    Xin, Tan; Yuanjie, Lü; Guodong, Gu; Li, Wang; Shaobo, Dun; Xubo, Song; Hongyu, Guo; Jiayun, Yin; Shujun, Cai; Zhihong, Feng

    2015-07-01

    AlGaN/GaN high electron-mobility transistors (HEMTs) with 5 nm AlN passivation by plasma enhanced atomic layer deposition (PEALD) were fabricated, covered by 50 nm SiNx which was grown by plasma enhanced chemical vapor deposition (PECVD). With PEALD AlN passivation, current collapse was suppressed more effectively and the devices show better subthreshold characteristics. Moreover, the insertion of AlN increased the RF transconductance, which lead to a higher cut-off frequency. Temperature dependence of DC characteristics demonstrated that the degradations of drain current and maximum transconductance at elevated temperatures for the AlN/SiNx passivated devices were much smaller compared with the devices with SiNx passivation, indicating that PEALD AlN passivation can improve the high temperature operation of the AlGaN/GaN HEMTs. Project supported by the National Natural Science Foundation of China (No. 60890192).

  10. Ni{sub 3}Al aluminide alloys

    SciTech Connect

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  11. Suspected variables among Al Sufi stars.

    NASA Astrophysics Data System (ADS)

    Hoffleit, D.

    In the tenth century Al Sufi compiled a catalogue of some 1100 stars. J.E. Gore, around 1900, wrote extensively on the magnitudes of these stars. On intercomparing them with a few other catalogues, Gore surmised that some 38 stars appeared to show secular variations. Here all the Al Sufi magnitudes have been compared with numerous additional sources, but smooth secular variations are not substantiated although some stars seem to have undergone comparatively sudden changes after about 1600. About 70 Al Sufi stars are now named or suscpected variable stars, but nearly all with amplitudes under 0.3 V.

  12. Characterization of AlInN/AlN/GaN Heterostructures with Different AlN Buffer Thickness

    NASA Astrophysics Data System (ADS)

    Çörekçi, S.; Dugan, S.; Öztürk, M. K.; Çetin, S. Ş.; Çakmak, M.; Özçelik, S.; Özbay, E.

    2016-05-01

    Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and Hall-effect measurements. The symmetric (0002) plane with respect to the asymmetric (10bar{1} 2) plane in the 280-nm-thick AlN buffer has a higher crystal quality, as opposed to the 400-nm-thick buffer. The thinner buffer improves the crystallinity of both (0002) and (10bar{1} 2) planes in the GaN layers, it also provides a sizeable reduction in dislocation density of GaN. Furthermore, the lower buffer thickness leads to a good quality surface with an rms roughness of 0.30 nm and a dark spot density of 4.0 × 108 cm-2. The optical and transport properties of the AlInN/AlN/GaN structure with the relatively thin buffer are compatible with the enhancement in its structural quality, as verified by XRD and AFM results.

  13. Characterization of AlInN/AlN/GaN Heterostructures with Different AlN Buffer Thickness

    NASA Astrophysics Data System (ADS)

    Çörekçi, S.; Dugan, S.; Öztürk, M. K.; Çetin, S. Ş.; Çakmak, M.; Özçelik, S.; Özbay, E.

    2016-07-01

    Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and Hall-effect measurements. The symmetric (0002) plane with respect to the asymmetric (10bar{1}2) plane in the 280-nm-thick AlN buffer has a higher crystal quality, as opposed to the 400-nm-thick buffer. The thinner buffer improves the crystallinity of both (0002) and (10bar{1}2) planes in the GaN layers, it also provides a sizeable reduction in dislocation density of GaN. Furthermore, the lower buffer thickness leads to a good quality surface with an rms roughness of 0.30 nm and a dark spot density of 4.0 × 108 cm-2. The optical and transport properties of the AlInN/AlN/GaN structure with the relatively thin buffer are compatible with the enhancement in its structural quality, as verified by XRD and AFM results.

  14. Diffusion at the Al/Al oxide interface during electromigration in wide lines

    NASA Astrophysics Data System (ADS)

    Augur, R. A.; Wolters, R. A. M.; Schmidt, W.; Dirks, A. G.; Kordić, S.

    1996-03-01

    Significant large-scale modification of the surface of Al-Si conductors was observed, due to electromigration in wide lines and under low stress conditions. After electromigration stressing the Al layers showed local thickness variations, i.e., damage by thinning. The mechanism underlying this damage causes substantial metal transport. Nevertheless, damage by thinning has received little attention in the past. Thinning was observed: (1) in a number of different alloys (Al-Si, Al-Cu, Al-Si-V, and Al-Si-V-Pd), (2) with a number of different underlayers [SiO2, W-Ti (no vacuum break after Al deposition) and W-Ti (oxidized surface before Al deposition)], (3) over an extended temperature range, (4) over a range of current density, and (5) in structures with and without passivation. The results show that thinning is a general phenomenon. An activation energy of approximately 0.5 eV was determined for the temperature dependence of a combined mechanism of concurrent thinning plus voiding in Al99Si1. Several alternatives are examined to explain the observations, namely mass movement along dislocations, Al bulk diffusion, and diffusion at the interface between the Al and its oxide. It is shown that diffusion at the Al/Al oxide interface most probably plays an important role in the damage mechanism, even under stress conditions where grain boundary diffusion is traditionally thought to dominate. Results also showed that alloying of Al with Pd can reduce the effects of damage by thinning.

  15. Electroforming and Ohmic contacts in Al-Al2O3-Ag diodes

    NASA Astrophysics Data System (ADS)

    Hickmott, T. W.

    2012-03-01

    Electroforming of metal-insulator-metal (MIM) diodes is a non-destructive dielectric breakdown process that changes the diode from its initial high resistance state (HRS) to a low resistance state (LRS). After electroforming, resistance switching memories (RSMs) use voltages to switch from HRS to LRS and back. Many MIM combinations are proposed for use in RSMs. In many cases conduction in the LRS is nearly temperature independent at low temperatures; an Ohmic contact with a barrier to electron injection of ˜0 eV results from electroforming. Electroforming of Al-Al2O3-Ag diodes with amorphous anodic Al2O3 thicknesses between 12 and 41 nm has been studied. Two anodizing electrolytes have been used; 0.1 M ammonium pentaborate (bor-H2O) and a solution of 0.1 M of ammonium pentaborate per liter of ethylene glycol (bor-gly). Polarization of Al2O3 and negative charge in Al2O3 are much larger when Al2O3 is formed in bor-H2O solution than when Al is anodized in bor-gly solution. Electroforming of Al-Al2O3-Ag diodes results in an Ohmic contact at the Al-Al2O3 interface, voltage-controlled negative resistance (VCNR) in the current-voltage (I-V) characteristics, electroluminescence (EL), and electron emission into vacuum (EM) from filamentary conducting channels. Two distinct modes of electroforming occur for Al-Al2O3-Ag diodes. α-forming occurs for 2.5 V ≲ VS ≲ 5 V, where VS is the applied voltage. It is characterized by an abrupt current jump with the simultaneous appearance of EL and EM. β-forming occurs for VS ≳ 7 V. I-V curves, EL, and EM develop gradually and are smaller than for α-forming. Electroforming occurs more readily for diodes with Al2O3 formed in bor-H2O that have greater defect densities. Fully developed I-V curves have similar VCNR, EL, and EM after α-forming or β-forming. A model is proposed in which excited states of F-centers, oxygen vacancies in amorphous anodic Al2O3, form defect conduction bands. Electroforming that results in an Ohmic

  16. Stem Cells Deemed Safe for ALS Patients

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159627.html Stem Cells Deemed Safe for ALS Patients But further research ... June 29, 2016 (HealthDay News) -- Scientists report that stem cell therapy appears to be safe for people with ...

  17. Pesticides Linked to Raised Risk of ALS

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158737.html Pesticides Linked to Raised Risk of ALS One toxin ... MONDAY, May 9, 2016 (HealthDay News) -- Exposure to pesticides and other chemicals may increase the risk for ...

  18. Stem Cells Deemed Safe for ALS Patients

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_159627.html Stem Cells Deemed Safe for ALS Patients But further ... June 29, 2016 (HealthDay News) -- Scientists report that stem cell therapy appears to be safe for people ...

  19. ALS and Oxidative Stress: The Neurovascular Scenario

    PubMed Central

    Thakur, Keshav; Gupta, Pawan Kumar

    2013-01-01

    Oxidative stress and angiogenic factors have been placed as the prime focus of scientific investigations after an establishment of link between vascular endothelial growth factor promoter (VEGF), hypoxia, and amyotrophic lateral sclerosis (ALS) pathogenesis. Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter and mutant superoxide dismutase 1 (SOD1) which are characterised by atrophy and muscle weakness resulted in phenotype resembling human ALS in mice. This results in lower motor neurodegeneration thus establishing an important link between motor neuron degeneration, vasculature, and angiogenic molecules. In this review, we have presented human, animal, and in vitro studies which suggest that molecules like VEGF have a therapeutic, diagnostic, and prognostic potential in ALS. Involvement of vascular growth factors and hypoxia response elements also highlights the converging role of oxidative stress and neurovascular network for understanding and treatment of various neurodegenerative disorders like ALS. PMID:24367722

  20. Glial cells in ALS: the missing link?

    PubMed

    Raibon, Elsa; Todd, Lisa Marie; Möller, Thomas

    2008-08-01

    Amyotrophic lateral sclerosis (ALS) was initially known as Charcot's sclerosis, named after the French neurobiologist and physician Jean-Martin Charcot who first described this type of muscular atrophy in the early nineteenth century. In the United States, ALS became widely known as Lou Gehrig's disease after the famous baseball player who succumbed to the disease in the late 1930s. Currently, ALS is the most common motor neuron disease, with a worldwide incidence of 8 cases per 100,000 population per year. Familial forms constitute approximately 5% to 10% of all cases. Onset increases with age, with a peak in the seventh decade and a slight preponderance (relative risk, 1.3-1.5) among men compared with women. Rapid progression of motor neuron loss leads to death an average of 3 to 5 years after symptom onset. The cause of ALS remains unknown and there is still no curative therapy. PMID:18625409

  1. Thermal Conductivity of Al-Salt Composites

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Mei; Wang, Lijun; Seetharaman, Seshadri

    2015-11-01

    With a view to examine the possibility of estimating the content of entrapped metallic aluminium in the salt cake from aluminium remelting, the thermal diffusivity of reference composites of KCl-NaCl-Al was measured as a function of aluminium metal content at room temperature. The thermal conductivity of the reference composites was found to increase with the metallic Al content. The lumped parameter model approach was carried out to discuss the influence of different geometry arrangements of each phase, viz. air, salts and metallic aluminium on the thermal conductivity. Application of the present results to industrial samples indicates that factors such as the interfacial condition of metallic Al particles have to be considered in order to estimate the amount of entrapped Al in the salt cake.

  2. ALS: Recent Developments from Genetics Studies.

    PubMed

    Therrien, Martine; Dion, Patrick A; Rouleau, Guy A

    2016-06-01

    Amyotrophic lateral sclerosis (ALS) is a fatal disorder that is characterized by a progressive degeneration of the upper and lower motor neurons. Most cases appear to be sporadic, but 5-10 % of cases have a family history of the disease. High-throughput DNA sequencing and related genomic capture tools are methodological advances which have rapidly contributed to an acceleration in the discovery of genetic risk factors for both familial and sporadic ALS. It is interesting to note that as the number of ALS genes grows, many of the proteins they encode are in shared intracellular processes. This review will summarize some of the recent advances and gene discovery made in ALS. PMID:27113253

  3. Pesticides Linked to Raised Risk of ALS

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_158737.html Pesticides Linked to Raised Risk of ALS One toxin ... MONDAY, May 9, 2016 (HealthDay News) -- Exposure to pesticides and other chemicals may increase the risk for ...

  4. 17th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2004-11-29

    It's not exactly Russian roulette, but scheduling October events outdoors is not risk-free, even in usually sunny California. An overflow crowd of more than 400 registered users, ALS staff, and vendors enjoyed a full indoor program featuring science highlights and workshops spread over two and a half days from October 18 to October 20. However, a major storm, heralding the onset of the San Francisco Bay Area rainy season, posed a few weather challenges for the events on the ALS patio.

  5. Itinerant antiferromagnetism of TiAl alloys

    NASA Astrophysics Data System (ADS)

    Petrişor, T.; Pop, I.; Giurgiu, A.; Farbaş, N.

    1986-06-01

    Magnetic susceptibility measurements of TiAl alloys are reported. Aluminium, by alloying, acts on the Néel temperature of pure titanium giving rise to a complicated phase diagram. A theoretical model, based on the itinerant antiferromagnetism model of chromium is proposed in order to explain the magnetic phase diagram of TiAl alloys. The experimental and theoretical magnetic phase diagram are in good agreement.

  6. Magnetism of Al-Mn quasicrystals

    SciTech Connect

    Liu, F.; Khanna, S.N.; Magaud, L.; Jena, P. ); de Coulon, V.; Reuse, F. ); Jaswal, S.S.; He, X. ); Cyrot-Lackman, F. )

    1993-07-01

    The effect of symmetry and concentration of Mn on the magnetism of Al-Mn quasicrystals has been investigated through self-consistent density-functional calculations using molecular clusters and supercell band-structure schemes. A single Mn atom surrounded by 54 Al atoms in an icosahedral or a cuboctahedral structure is found to be nonmagnetic. However, as the Mn concentration is increased, moments develop on Mn sites whose magnitude and coupling depend on their location.

  7. Next-generation sequencing of 28 ALS-related genes in a Japanese ALS cohort.

    PubMed

    Nakamura, Ryoichi; Sone, Jun; Atsuta, Naoki; Tohnai, Genki; Watanabe, Hazuki; Yokoi, Daichi; Nakatochi, Masahiro; Watanabe, Hirohisa; Ito, Mizuki; Senda, Jo; Katsuno, Masahisa; Tanaka, Fumiaki; Li, Yuanzhe; Izumi, Yuishin; Morita, Mitsuya; Taniguchi, Akira; Kano, Osamu; Oda, Masaya; Kuwabara, Satoshi; Abe, Koji; Aiba, Ikuko; Okamoto, Koichi; Mizoguchi, Kouichi; Hasegawa, Kazuko; Aoki, Masashi; Hattori, Nobutaka; Tsuji, Shoji; Nakashima, Kenji; Kaji, Ryuji; Sobue, Gen

    2016-03-01

    We investigated the frequency and contribution of variants of the 28 known amyotrophic lateral sclerosis (ALS)-related genes in Japanese ALS patients. We designed a multiplex, polymerase chain reaction-based primer panel to amplify the coding regions of the 28 ALS-related genes and sequenced DNA samples from 257 Japanese ALS patients using an Ion Torrent PGM sequencer. We also performed exome sequencing and identified variants of the 28 genes in an additional 251 ALS patients using an Illumina HiSeq 2000 platform. We identified the known ALS pathogenic variants and predicted the functional properties of novel nonsynonymous variants in silico. These variants were confirmed by Sanger sequencing. Known pathogenic variants were identified in 19 (48.7%) of the 39 familial ALS patients and 14 (3.0%) of the 469 sporadic ALS patients. Thirty-two sporadic ALS patients (6.8%) harbored 1 or 2 novel nonsynonymous variants of ALS-related genes that might be deleterious. This study reports the first extensive genetic screening of Japanese ALS patients. These findings are useful for developing genetic screening and counseling strategies for such patients. PMID:26742954

  8. Metastability in the MgAl2O4-Al2O3 System

    DOE PAGESBeta

    Wilkerson, Kelley R.; Smith, Jeffrey D.; Hemrick, James G.

    2014-07-22

    Aluminum oxide must take a spinel form ( γ-Al2O3) at elevated temperatures in order for extensive solid solution to form between MgAl2O4 and α-Al2O3. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevatedmore » temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.« less

  9. Excitotoxicity in ALS: Overstimulation, or overreaction?

    PubMed

    King, Anna E; Woodhouse, Adele; Kirkcaldie, Matthew T K; Vickers, James C

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disease that results in motor dysfunction and death, generally from respiratory failure. 90% of ALS cases are sporadic with no known cause. Familial cases have been linked with mutations in several disparate classes of genes, including those involved in DNA/RNA metabolism, protein misfolding, oxidative stress and the cytoskeleton, leading to the proposition that ALS could be a multi-factorial disease. However, alterations in excitability have been reported in all types of ALS cases, and may be a common disease mechanism predisposing neurons to degeneration. Excitotoxicity has long been suspected as a mediator in the disease process, and may arise from changes in synaptic inputs, or alterations in the excitability of the neurons being stimulated. Although the glutamatergic system is widely recognised as a therapeutic avenue with the potential to extend lifespan and delay disease onset, the causes of altered excitability in ALS are currently unclear and warrant further investigation. This article reviews current evidence of alterations to excitatory and inhibitory signalling in the cortex and spinal cord, and in the intrinsic excitability of motor neurons, in ALS. PMID:26584004

  10. Clinical trials for neuroprotection in ALS.

    PubMed

    Siciliano, G; Carlesi, C; Pasquali, L; Piazza, S; Pietracupa, S; Fornai, F; Ruggieri, S; Murri, L

    2010-07-01

    Owing to uncertainty on the pathogenic mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) riluzole remains the only available therapy, with only marginal effects on disease survival. Here we review some of the recent advances in the search for disease-modifying drugs for ALS based on their putative neuroprotective effetcs. A number of more or less established agents have recently been investigated also in ALS for their potential role in neuroprotection and relying on antiglutamatergic, antioxidant or antiapoptotic strategies. Among them Talampanel, beta-lactam antibiotics, Coenzyme Q10, and minocycline have been investigated. Progress has also been made in exploiting growth factors for the treatment of ALS, partly due to advances in developing effective delivery systems to the central nervous system. A number of new therapies have also been identified, including a novel class of compounds, such as heat-shock protein co-inducers, which upregulate cell stress responses, and agents promoting autophagy and mitochondriogenesis, such as lithium and rapamycin. More recently, alterations of mRNA processing were described as a pathogenic mechanism in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations. This knowledge is expected to improve our understanding of the pathogenetic mechanism in ALS and developing more effective therapies. PMID:20406180

  11. Modeling of precipitation in Al alloys

    SciTech Connect

    Asta, M.; Foiles, S.M.; Wolfer, W.G.

    1996-10-01

    Objective was the development of a computational model of precipitation from a supersaturated alloy solid solution. The model is based on the formalism of chemical-reaction-rate theory combined with classical descriptions of precipitate thermodynamic properties and a mean-field treatment of diffusion-limited growht and coarsening. For the case of precipitation of Al{sub 3}Sc in supersaturated Al-Sc alloys, it is demonstrated how the model can be used to calculate number densities and size distributions of precipitates as a function of aging time and temperature, including effects of continuous cooling and thermally generated point defects. Application of the model to a specific alloy system requires knowledge of diffusion data, point defect energetics, and thermodynamic properties for bulk phases and interphase interfaces. For interfaces and point defects, thermodynamic data can be difficult to measure and reliable values of defect free energies are often unavailable. For this reason, part of the efforts were devoted to applying semiempirical and first-principles atomistic techniques to the calculation of interfacial and point-defect thermodynamic properties. This report discusses applications for interphase interfaces in the Al-Ag, Al-Sc, and Al-Li alloy systems. We also describe atomistic work aimed at understanding the energetics of vacancy clusters in Al. These clusters serve as sinks for isolated vacancies during aging and their growth can lead to more complex defects, such as dislocation loops, that act as heterogeneous nucleation sites.

  12. How common are ALS plateaus and reversals?

    PubMed Central

    Vaughan, Timothy; Wicks, Paul; Heywood, Jamie; Sinani, Ervin; Selsov, Roger; Macklin, Eric A.; Schoenfeld, David; Cudkowicz, Merit; Sherman, Alex

    2016-01-01

    Objective: To determine the frequency of amyotrophic lateral sclerosis (ALS) plateaus and reversals in the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database. Methods: We analyzed Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and ALSFRS–revised (ALSFRS-R) data from PRO-ACT participants. The frequencies of participants experiencing plateaus (periods where scores did not change) were calculated over 6-, 12-, and 18-month epochs. The percentage of participants ever experiencing reversals (periods where scores improved) of different lengths were also calculated and plotted. Results: Over 6 months, 25% of 3,132 participants did not decline. Over 12 months, 16% of 2,105 participants did not decline. Over 18 months, 7% of 1,218 participants did not decline. Small ALS reversals were also common, especially over shorter follow-up intervals; 14% of 1,343 participants had a 180-day interval where their ALSFRS-R slope was greater than zero. Fewer than 1% of participants ever experienced improvements of 4 or more ALSFRS-R points lasting at least 12 months. Conclusion: ALS plateaus and small reversals are common, especially over brief intervals. In light of these data, stable disease, especially for a short period of time, should not be interpreted as an ALS treatment effect. Large sustained ALS reversals, on the other hand, are rare, potentially important, and warrant further study. PMID:26658909

  13. Radio-Observaciones del OH EN la Coma del Cometa Halley Desde EL Hemisferio Sur

    NASA Astrophysics Data System (ADS)

    Silva, A. M.; Bajaja, E.; Morras, R.; Cersosimo, J. C.; Martin, M. C.; Arnal, E. M.; Poppel, W. G. L.; Colomb, F. R.; Mazzaro, J.; Olalde, J. C.; Boriakoff, V.; Mirabel, I. F.

    1987-05-01

    Se utilizó una antena de 30 metros del Instituto Argentino de Radioastronomía para observaciones diarias Cf ebrero a abril de 1986) de la transición en 1667 MHz ( λ = 18 cm) del OH en la coma del cometa Halley. De las observaciones realizadas se concluye: 1) El número promedio de moléculas de OH en la coma durante 37 días de observación fue de (8.9±3.5)x1034 moléculas, lo que implica una tasa de producción promedio de OH de 1.8x1029 moléculas seg-1 y consecuentemente una pérdida de masa promedio de 17±6 toneladas seg-1 . Este valor está de acuerdo con las mediciones realizadas por las sondas Vega y Giotto. 2) El monitoreo desde el lAR revela la existencia de variaciones bruscas en los flujos de absorción del OH. Estas variaciones son consistentes con los modelos que representan la producción gaseosa a partir de ejecciones y/o desprendimientos discretos de materia congelada del núcleo. 3) Las variaciones en la densidad de flujo son consistentes con las estimaciones de los tiem- pos de vida medios del H2O y del OH en presencia del campo de radiación solar. 4) Se encuentra una correlación entre la intensidad del flujo absorbido y anisotropías en Ia dinamica de la coma.

  14. Calidad de Imagen del Telescopio UNAM212

    NASA Astrophysics Data System (ADS)

    Cobos, F. J.; Teiada de Vargas, C.

    1987-05-01

    El telescopio UNAM2l2, del Observatorio Astronómico Nacional, situado en la Sierra de San Pedro Mártir (Baja California, México), cumplira en un futuro muy cercano siete años de uso para fines de investigación astronómica. Aunque en este tiempo no se ha efectuado un estudio sistemático acerca de su comportamiento óptico y de los factores que influyen en la calidad de las imágenes, se han realizado pruebas diversas, estudios parciales y reuniones especificas, cuyos resultados no siempre se han difundido ampliamente y generalmente no se han presentado por escrito. Es por ello que hemos creido necesario intentar una recopilación de la información existente para poder con ella establecer un diagnóstjco que, aunque no sea definitivo, sirva de base para futuros trabajos tendientes a optimizar el comportamiento óptico del telescopio. Es evidente que un buen número de las conclusiones que se presentan son resultado del trabajo de muchas personas ó de esfuerzos colectivos. Asimismo, hemos tratado de localizar información bibliográfica que pueda ser de utilidad. Nuestro objetivo primordial ha consistido en centrarnos en la óptica del telescopio y su calidad, pero también se han considerado otros aspectos que puedan afectar las imágenes obtenidas tales como: celda del primario, `seeing' local y externo, flexiones posibles en la estructura mecánica del telescopio, etc.

  15. Visiting the Gödel universe.

    PubMed

    Grave, Frank; Buser, Michael

    2008-01-01

    Visualization of general relativity illustrates aspects of Einstein's insights into the curved nature of space and time to the expert as well as the layperson. One of the most interesting models which came up with Einstein's theory was developed by Kurt Gödel in 1949. The Gödel universe is a valid solution of Einstein's field equations, making it a possible physical description of our universe. It offers remarkable features like the existence of an optical horizon beyond which time travel is possible. Although we know that our universe is not a Gödel universe, it is interesting to visualize physical aspects of a world model resulting from a theory which is highly confirmed in scientific history. Standard techniques to adopt an egocentric point of view in a relativistic world model have shortcomings with respect to the time needed to render an image as well as difficulties in applying a direct illumination model. In this paper we want to face both issues to reduce the gap between common visualization standards and relativistic visualization. We will introduce two techniques to speed up recalculation of images by means of preprocessing and lookup tables and to increase image quality through a special optimization applicable to the Gödel universe. The first technique allows the physicist to understand the different effects of general relativity faster and better by generating images from existing datasets interactively. By using the intrinsic symmetries of Gödel's spacetime which are expressed by the Killing vector field, we are able to reduce the necessary calculations to simple cases using the second technique. This even makes it feasible to account for a direct illumination model during the rendering process. Although the presented methods are applied to Gödel's universe, they can also be extended to other manifolds, for example light propagation in moving dielectric media. Therefore, other areas of research can benefit from these generic improvements. PMID

  16. A Precambrian cratonic block in the west-central Chihuahua - The Sierra del Nido cratonic block

    SciTech Connect

    Goodell, P.C. . Dept. of Geological)

    1993-02-01

    Precambrian rocks in west-central Chihuahua have been recognized by Denison (1969) and Mauger et al. (1983), on the basis of radiometric dating. The rocks are rhyolite clasts, and an allucthonous block, respectively, however their source direction and vergence can be measured. They point back to and are on the edge of a large, uniform, negative Bouguer gravity anomaly, having values greater than 200 milligals. The isotopic geochemical character of several Tertiary felsic fields within this anomalous are has been determined, and initial strontium isotopic ratios are all greater than 0.7055. Outside the anomalous area these ratios are lower, and Basin and Range extension tectonism is more evident. It is proposed that a Precambrian cratonic block, the Sierra del Nido, is present in the crust in west-central Chihuahua. It is reasonable to propose that it was decreted from North America during a Precambrian extensional (1.1. By ) event, from somewhere along the Arizona Transition Zone-Texas Linament region. The Sierra del Nido Block is separated form the ATZ-TL by a region of disrupted craton and extended crust, the Basin and Range Province. Implications of the pressure of the Sierra del Nido Block on other regional tectonic events will be discussed.

  17. Scattering induced by Al segregation in AlGaN/GaN heterostructures

    SciTech Connect

    Liu, Xiwen; Lu, Yanwu; Ji, Dong

    2015-08-17

    The effect of Al segregation near dislocations on the mobility of two-dimensional electron gas in AlGaN/GaN heterostructure-based high-electron-mobility transistors was investigated. Exponentially varied composition fluctuation was effective in describing Al segregation near dislocations when calculating scattering behavior. Mobility, which was limited by Al segregation surrounding dislocation lines, was calculated to be in the order of 10{sup 3} cm{sup 2}/Vs to 10{sup 6} cm{sup 2}/Vs. Results indicated that the mobility in AlGaN/GaN heterojunction was enhanced upon the reduction of dislocation density at low temperature. This study contributes to generating higher electron mobility in AlGaN/GaN heterojunctions.

  18. Thermal Properties in the MgAl2O4-Al2O3 System

    SciTech Connect

    Wilkerson, Dr. Kelley R.; Smith, Jeffrey D; Hemrick, James Gordon

    2013-01-01

    Compositional effects on the thermal diffusivity in the MgAl2O4-Al2O3 system were studied. The lowest thermal diffusivity, 0.0258 +/-5% cm/s, was measured between 79.8 and 83.9 wt% Al2O3 quenched from various temperatures between 1500 and 1700C. All of the chemistries in this range extend past the solvus, but still form a singe super-saturated spinel solid solution, regardless of quenching tempeature. A super-saturated metastable solid solution region was observed at 1500, 1600, and 1700C extending to 83.9, 85.2, and 87.1 wt% Al2O3, respectively. Beyond 83.9% Al2O3 a significant increase in thermal diffusivity, 11.7%, was observed and its attributed to precipiation of Al2O3 through spinodal decomposition.

  19. Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

    PubMed

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules. PMID:22163924

  20. TEM studies of oxidized NiAl and Ni3Al cross sections

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Ruhle, M.

    1989-01-01

    Cross sections of oxide scale/(Ni-Al) intermetallics were prepared by a new method and studied using primarily TEM. The cross sections were prepared by encasing an oxidized metal specimen sandwich in a low-melting-temperature zinc alloy. Observations of oxidized zirconium-doped beta-NiAl cross sections revealed crystallographic voids beneath an adherent Al2O3 scale. The oxide-metal interface was incoherent, but a high dislocation density in the metal near the interface suggested that a large tensile stress was induced by the attached oxide scale. A duplex Al2O3-NiAl2O4 scale formed on zirconium-doped and zirconium/boron-doped gamma-prime-Ni3Al alloys. Additional results are presented involving oxidation mechanisms and oxide-metal interface structures.

  1. Microscopic Properties of Long-Period Ordering in Al-Rich TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Hata, S.; Nakano, T.; Kuwano, N.; Itakura, M.; Matsumura, S.; Umakoshi, Y.

    2008-07-01

    The ordering mechanism of long-period superstructures (LPSs) in Al-rich TiAl alloys has been investigated by high-resolution transmission electron microscopy (HRTEM). The LPSs are classified in terms of arrangements of base clusters with different shapes and compositions formed in Ti-rich (002) layers of L10-TiAl matrix: square Ti4Al, fat rhombus Ti3Al, and lean rhombus Ti2Al type clusters. The HRTEM observations revealed that antiphase boundaries of long-range-ordered LPS domains and short-range-ordered microdomains are constructed by various space-filling arrangements of the base clusters. Such a microscopic property characterized by the base clusters and their arrangements is markedly analogous to that of the {left< {{text{1,1/2,0}}} rightrangle } * special-point ordering alloys such as Ni-Mo.

  2. Influence of RCS on Al-3Mg and Al-3Mg-0.25Sc alloys

    NASA Astrophysics Data System (ADS)

    Bhovi, Prabhakar M.; Venkateswarlu, K.

    2016-02-01

    An influence of repetitive corrugation and straightening (RCS) was studied on Al-3Mg and Al-3Mg-0.25Sc alloys up to eight passes. Each pass consist of a corrugation and followed by straightening. This has resulted in introducing large plastic strain in sample, and thus led to formation of sub-micron grain sizes with high angle grain boundaries. These sub grain formation was eventually resulted in improved mechanical properties. The average grain size of Al-3Mg-0.25Sc alloy after 8 passes yielded to ∼0.6pm. Microhardness, strength properties were evaluated and it suggests that RCS was responsible for high hardness values as compared to the as cast samples. The microhardness values after RCS were 105 HV and 130 HV for Al-3Mg and Al-3Mg-0.25Sc alloys, respectively. Similarly, ∼ 40% improvement in tensile strength from 240 MPa to 370 MPa was observed for Al- 3Mg-0.25Sc alloy after RCS process.Al-3Mg and Al-3Mg-0.25Scalloys exhibited maximum strength of 220 MPa and 370 MPa, respectively. It is concluded that RCS process has a strong influence on Al- 3Mg and Al-3Mg-0.25Sc alloys for obtaining improved mechanical properties and grain refinement. In addition to RCS process and presence of AESc precipitates in Al-3Mg-0.25Sc alloy had a significant role in grain refinement and improved mechanical properties as compared to Al-3Mg alloy.

  3. Remarks on Peinado et al.'s Analysis of J3Gen.

    PubMed

    Garcia-Alfaro, Joaquin; Herrera-Joancomartí, Jordi; Melià-Seguí, Joan

    2015-01-01

    Peinado et al. analyzed the security of the J3Gen pseudorandom number generator proposed by Melià-Seguí et al., and claimed weaknesses regarding its security properties. They also presented a deterministic attack based on the decimation of the J3Gen output sequences. We show that the assumptions made by Peinado et al. are not correct and that the proposed deterministic attack against J3Gen does not hold in practice. PMID:25781510

  4. Two-Phase (TiAl+TiCrAl) Coating Alloys for Titanium Aluminides

    NASA Technical Reports Server (NTRS)

    Brady, Michael P. (Inventor); Smialek, James L. (Inventor); Brindley, William J. (Inventor)

    1998-01-01

    A coating for protecting titanium aluminide alloys, including the TiAl gamma + Ti3Al (alpha(sub 2)) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C. is disclosed. This protective coating consists essentially of titanium, aluminum. and chromium in the following approximate atomic ratio: Ti(41.5-34.5)Al(49-53)Cr(9.5-12.5)

  5. Another Security Improvement over the Lin et al.'s E-voting Scheme

    NASA Astrophysics Data System (ADS)

    Asaar, Maryam Rajabzadeh; Mohajeri, Javad; Salmasizadeh, Mahmoud

    In 2003, Lin et al. have proposed an electronic voting scheme which can be utilized in large-scale elections, and claimed it detects double voting. But in this paper, by presenting an attack, we show that voters can successfully vote more than once without being detected. Hence, we propose a new modified scheme based on the Lin et al.'s scheme with the same efficiency to solve this weakness and analyze its security.

  6. Excited states of 26Al studied via the reaction 27Al(d,t)

    NASA Astrophysics Data System (ADS)

    Srivastava, Vishal; Bhattacharya, C.; Rana, T. K.; Manna, S.; Kundu, S.; Bhattacharya, S.; Banerjee, K.; Roy, P.; Pandey, R.; Mukherjee, G.; Ghosh, T. K.; Meena, J. K.; Roy, T.; Chaudhuri, A.; Sinha, M.; Saha, A. K.; Asgar, Md. A.; Dey, A.; Roy, Subinit; Moin Shaikh, Md.

    2016-05-01

    The reaction 27Al(d,t) at 25 MeV was utilized to study the excited states of 26Al. The angular distributions of the observed excited states of 26Al were analyzed with zero range distorted wave Born approximation as well as by incorporating finite range correction parameters to extract spectroscopic factors. The two sets of extracted spectroscopic factors were compared with each other to see the effect of using finite range correction in the transfer form factor.

  7. Temperature dependence diode parameters studies of Al/CuPc/n-Si/Al structure

    NASA Astrophysics Data System (ADS)

    Kumar, Ratnesh; Kaur, Ramneek; Sharma, Mamta; Kaur, Maninder; Tripathi, S. K.

    2015-08-01

    This paper presents the fabrication of Al/CuPc/n-Si/Al metal-organic-semiconductor diode. The copper phthalocyanine as organic layer is deposited on Si substrate by thermal evaporation technique. The temperature dependent current-voltage measurements are performed on Al/CuPc/n-Si structure. The important diode parameters i.e. the barrier height and ideality factor have been calculated. The temperature dependence of barrier height and ideality factor has been studied.

  8. The lowest ionization potentials of Al2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.

    1988-01-01

    Potential curves for the lowest two electronic states (X 2 sigma g + and A 2 pi u) of Al2(+) were computed using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2(+) X 2 sigma g +) of the Al2 X 3 pi u ground state is calculated to occur around 6.1 eV, in excellent agreement with the experimental range of 6.0 to 6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2(+) A 2 pi u) occurs near 6.4 eV, also within the experimental range. The adiabatic IP of 5.90 eV is in good agreement with the value of 5.8 to 6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision induced dissociation processes of Al3(+). The computed IP values are somewhat larger than those deduced from branching ratios in cluster fragmentation experiments by Jarrold and co-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3 sigma g -, but the separation between the two lowest states of Al2 is so small that it is likely that both are populated in the experiments, so that this does not provide unambiguous support for the recent theoretical assignment of the ground state as 3 pi u.

  9. The Torres del Paine intrusion as a model for a shallow magma chamber

    NASA Astrophysics Data System (ADS)

    Baumgartner, Lukas; Bodner, Robert; Leuthold, Julien; Muntener, Othmar; Putlitz, Benita; Vennemann, Torsten

    2014-05-01

    The shallow magmatic Torres del Paine Intrusive Complex (TPIC) belongs to a series of sub-volcanic and plutonic igneous bodies in Southern Chile and Argentina. This trench-parallel belt is located in a transitional position between the Patagonia Batholith in the West, and the alkaline Cenozoic plateau lavas in the East. While volumetrically small amounts of magmatism started around 28 my ago in the Torres del Paine area, and a second period occurred between 17-16 Ma, it peaked with the TPIC 12.59-12.43 Ma ago. The spectacular cliffs of the Torres del Paine National park provide a unique opportunity to study the evolution of a very shallow magma chamber and the interaction with its host rocks. Intrusion depth can be estimated based on contact metamorphic assemblages and granite solidus thermobarometry to 750±250 bars, corresponding to an intrusion depth of ca. 3km, ca. 500m above the base of the intrusion. Hornblende thermobarometry in mafic rocks agrees well with these estimates (Leuthold et al., 2014). The TPIC is composed of a granitic laccolith emplaced over 90ka (Michel et al., 2008) in 3 major, several 100m thick sheets, forming an overall thickness of nearly 2 km. Contacts are sharp between sheets, with the oldest sheet on the top and the youngest on the bottom (Michel et al., 2008). The granitic laccolith is under-plated by a ca. 400m thick mafic laccolith, built up over ca. 50ka (Leuthold et al. 2012), constructed from the bottom up. Granitic and mafic sheets are themselves composed of multiple metric to decametric pulses, mostly with ductile contacts between them, resulting in outcrop patterns resembling braided stream sediments. The contact of the TPIC with the Cretaceous flysch sediments document intrusion mechanism. Pre-existing sub-horizontal fold axes are rotated in the roof of the TPIC, clearly demonstrating ballooning of the roof; no ballooning was observed in the footwall of the intrusion. Extension during ballooning of the roof is indicated by

  10. The new structure type Gd3Ni7Al14.

    PubMed

    Pukas, Svitlana; Gladyshevskii, Roman

    2015-11-01

    The crystal structure of Gd3Ni7Al14 (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two-layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al4Gd2 and Al6) are observed, the Al atoms are inside tetragonal (Ni2Al2Gd4, Ni2Al4Gd2, Al4Gd4, Ni4Al4 and Al8) and pentagonal (Ni4Al6 and Al10) prisms, while the Gd atoms are at the centres of pentagonal (Ni4Al6) and hexagonal (Ni4Al8) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd3Ni7Al14 are similar to those of the intermetallides PrNi2Al3 and ZrNiAl. In all these structures, Ni-centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three-dimensional framework with six-membered rings in the (001) plane in the case of the PrNi2Al3 and ZrNiAl types. In the case of Gd3Ni7Al14, six-membered rings are also observed, but only two-thirds of the rings are interconnected via prism edges. PMID:26524174

  11. Long range order and vacancy properties in Al-rich Fe{sub 3}Al and Fe{sub 3}Al(Cr) alloys

    SciTech Connect

    Kim, S.M.; Morris, D.G.

    1998-05-01

    Neutron powder diffraction measurements have been carried out in situ from room temperature to about 100 C in Fe28Al (28 at.% Al), Fe32.5Al (32.5 at.% Al) and Fe28Al15Cr (28 at.% Al, 5 at.% Cr) alloys. X-ray diffraction and TEM studies provided supporting information. The data were analyzed to obtain information about the temperature dependence of the DO{sub 3} and B2 long range order parameters, the location of the Cr atoms and their effect on the ordering energies, and on the vacancy formation and migration properties in Fe28Al and Fe32.5Al alloys. The location of the ternary alloying addition in DO{sub 3} and B2 ordered Al-rich Fe{sub 3}Al is shown to be consistent with considerations of interatomic bond energies.

  12. [I costi farmacologici della terapia di conversione con farmaci biologici nel carcinoma del colon-retto con metastasi epatiche].

    PubMed

    Giuliani, Jacopo; Bonetti, Andrea

    2016-08-01

    Riassunto. Lo scopo di questo studio è quello di valutare i costi dei farmaci (con particolare riferimento alle terapie con farmaci biologici) utilizzati nella terapia di conversione in una popolazione non selezionata di pazienti affetti da carcinoma del colon-retto in stadio avanzato, al fine di ottenere una resezione epatica R0. In questa rassegna sono stati selezionati i report completi e gli aggiornamenti di tutti gli studi clinici randomizzati (di fase II e fase III) che confrontassero almeno 2 regimi di terapia con farmaci biologici in prima linea in pazienti affetti da carcinoma del colon-retto in stadio avanzato di malattia. I costi dei farmaci sono stati ricavati dalla nostra Farmacia Ospedaliera e sono espressi in euro (€). Il nostro studio inizia con la valutazione di 683 abstract. 48 tria sono stati considerati adeguati per una successiva analisi. Una valutazione più approfondita ha portato all'esclusione di 37 trial, lasciando alla valutazione finale 11 studi clinici randomizzati (3 trial di fase II, per un totale di 522 pazienti, e 8 studi di fase III, per un totale di 7191 pazienti). I costi dei farmaci utilizzati nella terapia di conversione aumentano con la sostituzione del 5-fluorouracile con la capecitabina e, in misura maggiore, con l'introduzione degli agenti biologici. In questo lavoro sono presentati due punti chiave. Primo, i costi degli agenti farmacologici utilizzati nei regimi di prima linea a base di agenti biologici più comunemente utilizzati nel trattamento del carcinoma del colon-retto in stadio avanzato sono molto variabili. Secondo, i dati di efficacia dei regimi pubblicati, in termini di tassi di resezione, dipendono dalla selezione dei pazienti, dalle caratteristiche del tumore e dal tipo di schema di terapia. PMID:27571559

  13. Strain Rates and Grain Growth in Al 5754 and Al 6061 Friction Stir Spot Welds

    NASA Astrophysics Data System (ADS)

    Gerlich, A.; Yamamoto, M.; North, T. H.

    2007-06-01

    The stir zone temperature and microstructures are compared in friction stir spot welds produced in Al 5754 and Al 6061 alloys. Electron backscattered diffraction was used to determine the relationship between tool rotation speed during welding and final stir zone grain size. Comparison of the grain sizes in rapidly quenched welds with those in air-cooled joints confirmed that grain growth occurred only in Al 6061 spot welds. There was no evidence of abnormal grain growth in the stir zones of Al 6061 welds; the final grain size could be represented using an Arrhenius equation. The strain rates during welding were determined by incorporating the stir zone temperature and average subgrain sizes in quenched spot welds in the Zener-Hollomon relation. When the tool rotation speed increased from 750 to 3000 RPM, the strain rate values ranged from 180 to 497 s-1 in Al 5754 spot welds and from 55 to 395 s-1 in Al 6061 spot welds. It is suggested that a no-slip boundary condition may be appropriate during numerical modeling of Al 5754 and 6061 friction stir spot welding. This is not the case during Al 7075, Al 2024, and Mg-alloy AZ91 spot welding because spontaneous melting facilitates slippage at the tool contact interface.

  14. High temperature deformation of NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Nix, W. D.

    1982-01-01

    The high temperature mechanical properties of the aluminides are reviewed with respect to their potential as high temperature structural materials. It is shown that NiAl and CoAl are substantially stronger than the pure metals Ni and Co at high temperatures and approach the strength of some superalloys, particularly when those superalloys are tested in "weak" directions. The factors that limit and control the high temperature strengths of NiAl and CoAl are examined to provide a basis for the development of intermetallic alloys of this type.

  15. Small Al clusters. II - Structure and binding in Al(n) (n = 2-6, 13)

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Bauschlicher, Charles W., Jr.; Halicioglu, Timur

    1987-01-01

    The structure and stability of aluminum clusters containing up to six atoms have been studied using correlated wave functions and extended basis sets. The lowest energy structure is planar for Al4 and Al5, but three dimensional for Al6. The icosahedral, hcp, fcc, and two planar structures of Al13 were considered at the SCF level. The lowest energy structure is the icosahedron, but the planar structures are fairly low lying even in this case. A simplified description using two- and three-body interaction potentials is found to agree well with the ab initio structures and binding energies.

  16. Synthesis of core-shell AlOOH hollow nanospheres by reacting Al nanoparticles with water.

    PubMed

    Lozhkomoev, A S; Glazkova, E A; Bakina, O V; Lerner, M I; Gotman, I; Gutmanas, E Y; Kazantsev, S O; Psakhie, S G

    2016-05-20

    A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers. PMID:27053603

  17. HYDROGEN ADSORPTION ON β-TiAl (001) AND Ni/TiAl (001) SURFACES

    NASA Astrophysics Data System (ADS)

    Mubarak, A. A. Karim; Alelaimi, Mahmoud

    2014-04-01

    In this paper, we present first principles calculations of the energetic, electronic and magnetic properties of the variant termination of TiAl (001) and Ni/TiAl (001) surfaces with and without hydrogen atoms. The calculations have been performed within the density functional theory using full-potential linearized augmented plane wave method. The generalized gradient approximation (GGA) is utilized as the exchange-correlation energy. The octahedral site is the stable absorption site of H atom in the β-TiAl system. This absorption reduces the cohesive energy of β-TiAl system due to increase in the lattice constant. The surface energy for both TiAl (001) terminations is calculated. The stable adsorption site of H atoms on the variant termination of TiAl (001) surface is performed. The adsorption energy of hydrogen on Ti is more energetic than that on Al. The adsorption of H atom on both terminations of H/Ni/TiAl (001) is more preferable at the bridge site. The adsorption energies are enhanced on Ni atom due to the contraction between d-Ni bands and TiAl substrate band.

  18. Synthesis of core–shell AlOOH hollow nanospheres by reacting Al nanoparticles with water

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, A. S.; Glazkova, E. A.; Bakina, O. V.; Lerner, M. I.; Gotman, I.; Gutmanas, E. Y.; Kazantsev, S. O.; Psakhie, S. G.

    2016-05-01

    A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.

  19. AlN/IDT/AlN/Sapphire SAW Heterostructure for High-Temperature Applications.

    PubMed

    Legrani, Ouarda; Aubert, Thierry; Elmazria, Omar; Bartasyte, Ausrine; Nicolay, Pascal; Talbi, Abdelkrim; Boulet, Pascal; Ghanbaja, Jaafar; Mangin, Denis

    2016-06-01

    Recent studies have evidenced that Pt/AlN/Sapphire surface acoustic wave (SAW) devices are promising for high-temperature high-frequency applications. However, they cannot be used above 700°C in air atmosphere as the Pt interdigital transducers (IDTs) agglomerate and the AlN layer oxidizes in such conditions. In this paper, we explore the possibility to use an AlN protective overlayer to concurrently hinder these phenomena. To do so, AlN/IDT/AlN/Sapphire heterostructures undergo successive annealing steps from 800°C to 1000°C in air atmosphere. The impact of each step on the morphology, microstructure, and phase composition of AlN and Pt films is evaluated using optical microscopy, scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), and secondary ion mass spectroscopy (SIMS). Finally, acoustical performance at room temperature of both protected and unprotected SAW devices are compared, as well as the effects of annealing on these performance. These investigations show that the use of an overlayer is one possible solution to strongly hinder the Pt IDTs agglomeration up to 1000°C. Moreover, AlN/IDT/AlN/Sapphire SAW heterostructures show promising performances in terms of stability up to 800°C. At higher temperatures, the oxidation of AlN is more intense and makes it inappropriate to be used as a protective layer. PMID:27076407

  20. Microstructure and strengthening of creep-tested cryomilled NiAl-AlN

    SciTech Connect

    Garg, A.; Whittenberger, J.D.; Luton, M.J.

    1997-12-31

    The B2 intermetallic NiAl is considered to be a prime candidate material for use as very high temperature structural components in gas turbine engines. The mechanical grinding of prealloyed NiAl powder in liquid nitrogen (cryomilling) results in an intermetallic matrix composite where micron sized particle free aluminide cores (grains) are surrounded by thin mantles comprised of nanometer sized AlN particles and NiAl grains. Under high temperature, slow strain rate conditions both compressive and tensile creep testing have shown that the mechanical strength of hot extruded cryomilled NiAl approaches the levels exhibited by advanced NiAl-based single crystals and simple Ni-based superalloys. Transmission electron microscopy of cryomilled materials tested between 1,100 and 1,300 K revealed little, if any, dislocation structure within the mantle regions, while the NiAl cores contained subgrains and dislocation networks after testing at all strain rates between 10{sup {minus}4} and 10{sup {minus}8} s{sup {minus}1}. These and other microstructural observations suggest that creep strength is the result of a fine NiAl grain/subgrain size, the inability of dislocations to move through the mantle and stabilization of the microstructure by the AlN particles.

  1. Quantum chemical study of the reactions of Al, AlO and AlOH with H2O2

    NASA Astrophysics Data System (ADS)

    Sharipov, Alexander S.; Starik, Alexander M.

    2016-02-01

    Quantum chemical calculations with the use of hybrid density functional with perturbative second-order correlation and dispersion correction are carried out to study the reactions of Al, AlO and AlOH with the H2O2 molecule. The values of energy barriers are estimated by means of extrapolation to the basis set limit. The energetically favorable reaction pathways have been revealed during the examination of the potential energy surfaces. Complex character of the processes under study has been established. It has been found that the initial stages of the considered processes are barrierless. Appropriate rate constants for principal channels of the reactions under study have been estimated by using capture model and canonical variational theory. The Arrhenius approximations for these channels have been proposed for the temperature range T = 300-4000 K.

  2. Cambios históricos en el aporte terrígeno de la cuenca del Río de la Plata sobre la plataforma interna Uruguaya

    NASA Astrophysics Data System (ADS)

    Marrero, Analía; Tudurí, Adriana; Pérez, Laura; Cuña, Caroline; Muniz, Pablo; Lopes Figueira, Rubens; Michaelovitch de Mahiques, Michel; Alves de Lima Ferreira, Paulo; Pittauerová, Daniela; Hanebuth, Till; García Rodríguez, Felipe

    2014-12-01

    El Río de la Plata (RdlP) presenta significativas variaciones naturales (hidrodinámicas y oceanográficas) asociadas a diferentes condiciones climáticas. El propósito de este trabajo es inferir los cambios de aportes continentales de sedimentos y su relación con las variaciones hidrológicas del Río de la Plata, a través del análisis de proxies sedimentológicos y geoquímicos en testigos de sedimentos de la plataforma interna uruguaya que registran los últimos 100 años, aproximadamente. A partir de la datación por 210Pb de dos testigos de sedimentos (GeoB 13813-4 y BAR1) se reconstruyó la geocronología del ambiente, y se relacionó con datos de las forzantes climáticas Pacific Decadal Oscillation, El Niño/La Niña Southern Oscillation, Atlantic Multidecadal Oscillation, y las anomalías hidrológicas de los ríos Paraná y Uruguay. Los valores más positivos y estables del Southern Oscillation Index, los cuales corresponden a fases La Niña, se observan en el periodo correspondiente entre 1910-1970, respecto al resto de la serie, donde se aprecia una mayor variabilidad y una tendencia hacia valores más negativos (eventos El Niño). Se hicieron dendrogramas (clustering) jerárquicos para ambos testigos. Para el testigo GeoB 13813-4, se utilizó la relación Ca/Ti y la granulometría, mientras que para BAR1 se recurrió a variables granulométricas y la tasa de sedimentación. El mayor aporte continental hacia la región de la plataforma adyacente al Río de la Plata registrado a partir del año 1970, podría ser el factor principal de los agrupamientos observados en los clusters para ambos testigos. Las agrupaciones mostraron una diferenciación en la década de 1970, lo que estaría asociado al aumento de los caudales de los ríos Paraná y Uruguay, durante las últimas tres décadas del siglo XX. Por otra parte se observa que la granulometría del testigo BAR1 presentó un mayor tamaño de grano y más variabilidad que en el caso del testigo Geo

  3. Reactions of CO2 on solid and liquid Al100+.

    PubMed

    Leslie, Katheryne L; Shinholt, Deven; Jarrold, Martin F

    2013-02-14

    The reactions of CO(2) on the Al(100)(+) cluster have been investigated as a function of cluster temperature (300-1100 K) and relative kinetic energy (0.2-10 eV). Two main products are observed at low cluster temperature: Al(100)O(+) (which is believed to result from a stripping reaction) and Al(100)CO(2)(+) from complex formation. As the cluster temperature is raised, both products dissociate by loss of Al(2)O. Al(100)O(+) forms Al(98)(+), while Al(100)CO(2)(+) forms Al(98)CO(+) and Al(96)C(+). In both cases, loss of Al(2)O turns-on above the melting temperature of Al(100)(+). This presumably occurs because the overall reaction leading to the loss of Al(2)O is significantly less endothermic for the liquid cluster than for the solid. PMID:22680973

  4. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  5. Survey and alignment at the ALS

    SciTech Connect

    Krebs, G.F.; Lauritzen, T.; Thur, W.

    1995-11-01

    This paper describes survey and alignment at the Lawrence Berkeley National Laboratory`s Advanced Light Source (ALS) accelerators from 1993 to 1995. The ALS is a 1.0 - 1.9 GeV electron accelerator producing extremely bright synchrotron light in the UV and soft-X-ray wavelengths. At the ALS, electrons are accelerated in a LINAC to 50 MeV, injected into a booster ring for further acceleration and finally injected into the storage ring. This is shown schematically in Figure 1. The storage ring, some 200 m in circumference, has been run with electron currents above 400 mA with lifetimes as high as 24 hours. The ALS is a third generation light source and requires for efficient storage ring operation, magnets aligned to within 150 mm of their ideal position. To accomplish this a network of monuments was established and their positions measured with respect to one another. The data was reduced using GEONET`` and STAR*NET`` software. Using the monuments as reference points, magnet positions were measured and alignment confirmed using the Kem Electronic Coordinate Determination System (ECDS``). A number of other papers dealing with survey and alignment (S&A) at the ALS have been written that may further elucidate some details of the methods and systems described in this paper.

  6. Del Mod System. 1972 Annual Report.

    ERIC Educational Resources Information Center

    Purnell, Charlotte H.

    The overall aim of the Del Mod System is the improvement of science programs taught in Delaware schools; it is a working agreement among the University of Delaware, Delaware Technical and Community College, Delaware State College, State Department of Public Instruction, industry, and the schools. It was formed to bring about changes in science…

  7. Andrea del Sarto rehabilitated: a psychoanalytic emendation.

    PubMed

    Trosman, Harry

    2002-01-01

    Ernest Jones's "The Influence of Andrea del Sarto's Wife on His Art" (1913) is an early example of psychoanalysis applied to the study of a prominent painter. Greatly influenced by Freud's Leonardo da Vinci and a Memory of His Childhood, Jones gave excessive credence to Vasari's highly prejudicial account of the life of del Sarto, on which the study relied heavily. Jones attempted to account psychologically for the circumstance that del Sarto, though highly skilled and "faultless," was not the equal of the three preeminent masters of the Italian High Renaissance: Leonardo, Michelangelo, and Raphael. Jones's uncritical acceptance of the Vasari biography encouraged him to view Sarto's assumed deficiency as the result of excessive attachment to his wife, a pathological uxoriousness. A contemporary psychoanalytic perspective, with its emphasis on the emotive response of the analyst, requires us to pay attention to the evocative nature of the work of the artist, an approach Jones neglected. In an examination of several paintings, the artist's sensitivity to the position of the spectator is explored, as is the interest in involving the viewer spatially and emotionally. An appreciation for the viewer's position is consistent with a capacity for using projected internal objects for creative purposes. The presence of this capacity suggests a revised view of del Sarto's contribution to art and of his relationship with his wife. PMID:12580329

  8. El contexto de la familia y el vecindario en la salud de los ancianos del estudio EPESE hispano

    PubMed Central

    Reyes-Ortiz, Carlos A.; Camacho, María E.; Eschbach, Karl; Markides, Kyriakos S.

    2014-01-01

    RESUMEN En este artículo se discute el papel de la familia y el vecindario en la salud de los ancianos méjico-americanos del estudio EPESE (Established Populations for Epidemiologic Studies of the Elderly) hispano. La paradoja epidemiológica consiste en que, a pesar de estar en desventaja socioeconómica, los ancianos hispanos tienen mortalidad relativamente menor que los ancianos de raza blanca. Esto es especialmente cierto cuando el anciano vive en los vecindarios donde hay un porcentaje alto de méjico-americanos. La familia también juega un papel importante en estos ancianos al disminuir el riesgo de institucionalización o de morbilidad. Asimismo, el estrés originado en problemas económicos o al depender económicamente de la familia, habiendo inmigrado en edades tardías, puede sobrepasar la capacidad de amortiguamiento del estrés y afectar la salud del anciano méjico-americano. PMID:25190897

  9. The mechanical properties of FeAl

    SciTech Connect

    Baker, I.; George, E.P.

    1996-12-31

    Only in the last few years has progress been made in obtaining reproducible mechanical properties data for FeAl. Two sets of observations are the foundation of this progress. The first is that the large vacancy concentrations that exist in FeAl at high temperature are easily retained at low temperature and that these strongly affect the low-temperature mechanical properties. The second is that RT ductility is adversely affected by water vapor. Purpose of this paper is not to present a comprehensive overview of the mechanical properties of FeAl but rather to highlight our understanding of key phenomena and to show how an understanding of the factors which control the yield strength and fracture behavior has followed the discovery of the above two effects. 87 refs, 9 figs.

  10. Boron strengthening in FeAl

    SciTech Connect

    Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C.; Carleton, R.L.; George, E.P.

    1998-11-01

    The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.

  11. Primary (AL) amyloidosis in plasma cell disorders.

    PubMed

    Müller, Antonia M S; Geibel, Annette; Neumann, Hartmut P H; Kühnemund, Alexander; Schmitt-Gräff, Annette; Böhm, Joachim; Engelhardt, Monika

    2006-01-01

    Primary (AL) amyloidosis is the most common form of systemic amyloidosis. The morbidity arises from extracellular deposition of immunoglobulin light chain (LC) fibrils in major organs, such as the kidneys, heart, and bowel. Organ dysfunction contributes to a high mortality and poor prognosis, with a median survival time of 1-2 years from diagnosis. Here, we present a 46-year-old man with an exceptional clinical course of an LC multiple myeloma with generalized amyloidosis, causing renal insufficiency, congestive heart failure, and complete intestinal necrosis. We have summarized recent knowledge on AL amyloidosis, its association with monoclonal gammopathies, clinical presentations, diagnostic tools, and treatment strategies. Our comprehensive overview of this rare and often fatal disease aims to increase the awareness of AL amyloidosis. This may facilitate earlier diagnosis, and thus allow initiation of prompt and specific therapies, which are indispensable in order to improve disease prognosis. PMID:16880241

  12. Posible origen del agua terrestre

    NASA Astrophysics Data System (ADS)

    di Sisto, R. P.; Orellana, R. B.; Brunini, A.

    The most plausible sources of the terrestrial water are found in the main external asteroid belt, the giant planetary region and in the Kuiper belt, because of its great presence of ices. However, the timing of earth planets's formation (108 years) marks an inferior limit for the dynamical lifetime of the objects of interest since the previous megaimpacts would volatilize the icy material previusly accreted. The central parameter that allow us to rebuild the origin of water in the solar system is the rate of the Deuterium/Hydrogen isotope (D/H). The D/H measured in three comets has an average value two times greater that the value measured in the terrestrial oceans. Morbidelli et al. support that the main part of the present buldge of water on earth was product of the accretion, in the last formation stages, of some planetary embryos originally formed in the external asteroid belt. In the Jupiter zone, the D/H could be of the order of the terrestrial value. Then, we would have there posible sources with an apropiate isotopic composition that have survived for several 108 years. These sources are: the Troyan asteroids, objects in the Jupiter-Saturn region and objects in the external limit of the asteroidal belt. As for this last group we have considered in this work, the Hilda Family asteroids. The Hilda Family asteroids are placed in the 3/2 mean motion resonance with Jupiter. From the present distribution of the Hilda's orbital parameters, we generate randomly, inicial conditions for 500 massless particles in the Hildas region. Trough numerical simulations we follow their dynamical evolution during 500 millon years and its final state. The mayority of these particles are eyected out of the Solar System (76 %) due to the gravitational action of Jupiter and only a 24 % stay in the resonance zone. The 8.1 % of the particles that leave the resonance, hit Jupiter. Some objects have encounters with the terrestrial planets. From the number of encounters with each planet

  13. Adhesion of metal carbide/nitride interfaces: Al/TiC and Al/TiN

    NASA Astrophysics Data System (ADS)

    Liu, L. M.; Wang, S. Q.; Ye, H. Q.

    2003-12-01

    We employ density functional theory to investigate and compare Al/TiC and Al/TiN interfaces by electronic structures, relaxed atomic geometries and adhesions. The results show that the preferred bonding site is the interfacial Al atoms above the ceramic's metalloid atoms for both systems. The calculated adhesion energies are quantitatively in agreement with other calculated and experimental results of Al on the carbide and nitride. A detailed comparison of the adhesion energies and relaxed structures shows weaker bonding and less relaxation in the Al/nitride case, which is correlated with the lower surface energy of the ceramic. We have thoroughly characterized the electronic structure and determined that the polar covalent Al3sp-C(N)2s bonds constitute the primary interfacial bonding interaction. The larger overlapping bonding states at the Al/TiC interface reveal the reason why it exhibits relatively larger adhesion energy. Cleavage may take place preferentially at the interface, especially for the Al/TiN, which is in agreement with experimental results.

  14. Directional Solidification and Mechanical Properties of NiAl-NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Chen, X. F.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1995-01-01

    Directional solidification of eutectic alloys is a promising technique for producing in-situ composite materials exhibiting a balance of properties. Consequently, the microstructure, creep strength and fracture toughness of directionally solidified NiAl-NiAlTa alloys were investigated. Directional solidification was performed by containerless processing techniques to minimize alloy contamination. The eutectic composition was found to be NiAl-15.5 at% Ta and well-aligned microstructures were produced at this composition. A near-eutectic alloy of NiAl-14.5Ta was also investigated. Directional solidification of the near-eutectic composition resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The off-eutectic alloy exhibited promising compressive creep strengths compared to other NiAl-based intermetallics, while preliminary testing indicated that the eutectic alloy was competitive with Ni-base single crystal superalloys. The room temperature toughness of these two-phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa.

  15. Synthesis of nanostructured AlN by solid state reaction of Al and diaminomaleonitrile

    SciTech Connect

    Rounaghi, S.A.; Eshghi, H.; Kiani Rashid, A.R.; Vahdati Khaki, J.; Samadi Khoshkhoo, M.; Scudino, S.; Eckert, J.

    2013-02-15

    The solid state reaction of diaminomaleonitrile (DAMN) with aluminum via both mechanochemical and thermal treatment routes was studied by X-ray diffraction and Fourier transform infrared spectroscopy. During the milling process, the reaction starts with the deammoniation of the DAMN molecules, followed by the formation of nanostructured AlN powder as the main solid product after milling for 7 h. The reactivity of the mixed powder was also investigated during the conventional thermal treatment process using differential scanning calorimetry, derivative thermogravimetry and thermogravimetric analysis. The results reveal that DAMN starts to polymerize at 192 Degree-Sign C by the elimination of the amine groups. Furthermore, increasing the annealing temperature leads to the formation of a nitrogen-containing carbonaceous material with the structure similar to non-crystalline carbon. However, no evidence for the formation of AlN was observed in the annealed samples even at temperatures as high as the Al melting point. - Graphical abstract: AlN nanoparticles obtained after milling of Al and diaminomaleonitrile (DAMN) for 12 h. Highlights: Black-Right-Pointing-Pointer Solid state reaction of diaminomaleonitrile (DAMN) with Al was studied via mechanochemical and thermal treatment routs. Black-Right-Pointing-Pointer Nanocrystalline AlN was successfully synthesized by the mechanochemical process. Black-Right-Pointing-Pointer The C/N material was formed by polymerization of DAMN during the thermal treatment process. Black-Right-Pointing-Pointer No reaction between DAMN and Al was detected during the thermal treatment method.

  16. Electronic circuits having NiAl and Ni.sub.3 Al substrates

    DOEpatents

    Deevi, Seetharama C.; Sikka, Vinod K.

    1999-01-01

    An electronic circuit component having improved mechanical properties and thermal conductivity comprises NiAl and/or Ni.sub.3 Al, upon which an alumina layer is formed prior to applying the conductive elements. Additional layers of copper-aluminum alloy or copper further improve mechanical strength and thermal conductivity.

  17. Transport mechanisms of leakage current in Al2O3/InAlAs MOS capacitors

    NASA Astrophysics Data System (ADS)

    Jin, Chengji; Lu, Hongliang; Zhang, Yimen; Zhang, Yuming; Guan, He; Wu, Lifan; Lu, Bin; Liu, Chen

    2016-09-01

    An Al2O3 layer is inserted between the InAlAs layer and the metal gate in InAs/AlSb HEMTs to suppress the leakage current. The transport mechanisms of leakage current in Al2O3/InAlAs metal-oxide-semiconductor (MOS) capacitors at both positive and negative biases at different temperatures ranging from 10 °C to 70 °C are investigated. For positive bias, the leakage current is dominated by Schottky emission. Based on the fitted straight lines, the relative dielectric constant of Al2O3 and the barrier height between Al2O3 and InAlAs are extracted. However, for negative bias, the leakage current is dominated by Frenkel-Poole (F-P) emission and the depth of the trap energy level from the conduction band (ϕt) is extracted. Furthermore, authors explain the reason why the dominating mechanisms at positive and negative biases are different.

  18. Disordered crystal structure of 20H-AlON, Al10O3N8

    NASA Astrophysics Data System (ADS)

    Banno, Hiroki; Funahashi, Shiro; Asaka, Toru; Hirosaki, Naoto; Fukuda, Koichiro

    2015-10-01

    The disordered crystal structure of 20H-AlON (Al10O3N8) was determined by combined use of X-ray powder diffraction and transmission electron microscopy. The title compound is hexagonal with space group P63/mmc (Z=2) and the unit-cell dimensions are a=0.307082(5) nm, c=5.29447(8) nm and V=0.432376(12) nm3. The structural model showed the positional disordering of three of the six Al sites in the unit cell. The reliability indices calculated from the Rietveld method were Rwp=6.97%, S (=Rwp/Re)=1.68, Rp=5.45%, RB=5.13% and RF=4.56%. We interpreted the disordered structure of 20H-AlON as a statistical average of six different types of ordered structural configurations, which are composed of an octahedral [Al(O, N)6] layer and tetrahedral [Al(O, N)4] layers. We demonstrated the high correlations between the hexagonal unit-cell dimensions and the octahedral layer concentrations for AlON and SiAlON polytypoids.

  19. An Alternative Perspective on von Winterfeldt et al.'s (1997) Test of Consequence Monotonicity

    ERIC Educational Resources Information Center

    Ho, Moon-Ho R.; Regenwetter, Michel; Niederee, Reinhard; Heyer, Dieter

    2005-01-01

    D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (see record 1997-03378-008) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a…

  20. Melting, Processing, and Properties of Disordered Fe-Al and Fe-Al-C Based Alloys

    NASA Astrophysics Data System (ADS)

    Satya Prasad, V. V.; Khaple, Shivkumar; Baligidad, R. G.

    2014-09-01

    This article presents a part of the research work conducted in our laboratory to develop lightweight steels based on Fe-Al alloys containing 7 wt.% and 9 wt.% aluminum for construction of advanced lightweight ground transportation systems, such as automotive vehicles and heavy-haul truck, and for civil engineering construction, such as bridges, tunnels, and buildings. The melting and casting of sound, porosity-free ingots of Fe-Al-based alloys was accomplished by a newly developed cost-effective technique. The technique consists of using a special flux cover and proprietary charging schedule during air induction melting. These alloys were also produced using a vacuum induction melting (VIM) process for comparison purposes. The effect of aluminum (7 wt.% and 9 wt.%) on melting, processing, and properties of disordered solid solution Fe-Al alloys has been studied in detail. Fe-7 wt.% Al alloy could be produced using air induction melting with a flux cover with the properties comparable to the alloy produced through the VIM route. This material could be further processed through hot and cold working to produce sheets and thin foils. The cold-rolled and annealed sheet exhibited excellent room-temperature ductility. The role of carbon in Fe-7 wt.% Al alloys has also been examined. The results indicate that Fe-Al and Fe-Al-C alloys containing about 7 wt.% Al are potential lightweight steels.

  1. A Comment on Eerland et al. (2016).

    PubMed

    Hart, William

    2016-03-01

    People imagine criminal behavior in greater detail and ascribe more blame to criminals when a description of a crime is written using the imperfective verb aspect (Hart & Albarracín, 2011, Experiment 3). An initiative to reproduce these findings conducted by Eerland et al. (2016) yielded a lack of replication. Eerland et al. have suggested that the original effect was likely driven by a Type I error produced by methodological aspects of the experiment, including low sample size. Recent conceptual replications of Hart and Albarracín's effect (Sherrill, Eerland, Zwaan, & Magliano, 2015), however, might imply the effect could be contingent on sample characteristics. PMID:26993281

  2. The ALS Storage Ring RF System

    SciTech Connect

    Taylor, B.; Lo, C.C.; Baptiste, K.; Guigli, J.; Julian, J.

    1993-05-01

    The ALS Storage Ring RF System is characterized by the use of the following features: (1) High power loading of two single cell cavities. (2) The use of a tubular ceramic input window employing aperture coupling. (3) The use of waveguide filters and matchers designed for HOM absorption. (4) A comprehensive HOM monitoring system. (5) The use of waveguide water-wedge loads for the magic tee and circulator loads. The results of cavity measurements and high power tests are reported together with the performance of the system during the commissioning and operation phases of the ALS project. Plans for future window development are discussed.

  3. Quadrupole scattering in PrAl2

    NASA Astrophysics Data System (ADS)

    Sablik, M. J.; Pureur, P.; Creuzet, G.; Fert, A.; Levy, P. M.

    1983-10-01

    We derive the spontaneous anisotropy of the resistivity of the ferromagnetic compound PrAl2 from magnetoresistance measurements on a single crystal of PrAl2. We ascribe this spontaneous anisotropy of the resistivity to scattering of the conduction electrons by the thermal quadrupole disorder and we account for our experimental results by using the theoretical model previously developed by us. We find that quadrupole scattering gives a very important contribution to the total magnetic disorder (spin and quadrupole) resistivity but that only a small part of this quadrupole contribution is anisotropic.

  4. Nb3Al Development for HEP Applications

    SciTech Connect

    Sumption, M.D.; Buta, F.; Collings, E.W.; Tomsic, M.; Phillips, J.; McFadden, K.; Wu, X

    2004-06-28

    Recent developments in Nb3Al strand for HEP applications are presented and discussed. The present state of available precursor is detailed. Two routes have been shown to lead to successful construction of MF NbAl composite wires. An extrusion method has so far produced the highest filament counts and smallest filament diameters, but requires more processing steps. A direct restack and draw approach has also been demonstrated which minimizes the number of processing steps while still leading to a high performance conductor. This latter route also allows for a lower cost per billet, potentially allowing the exploration of more process parameters.

  5. Complementary and Alternative Therapies in ALS

    PubMed Central

    Bedlack, Richard S.; Joyce, Nanette; Carter, Gregory T.; Pagononi, Sabrina; Karam, Chafic

    2015-01-01

    Synopsis Given the severity of their illness and lack of effective disease modifying agents, it is not surprising that most patients with ALS consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation and energy healing. This chapter reviews these in detail. We also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy and shared decision making. Finally, we review a program called ALSUntangled which using shared shared decision making to review alternative therapies for ALS. PMID:26515629

  6. Clinical and laboratory update on the DEL variant.

    PubMed

    Nuchnoi, Pornlada; Thongbus, Jairak; Srisarin, Apapan; Kerdpin, Usanee; Prachayasittikul, Virapong

    2014-01-01

    Serological assays for the RhD blood group are based on detection of the RhD antigen on human red blood cells using a specific anti-D antibody. The weak expression of the RhD antigen in the DEL variant hinders the sensitivity of conventional serological assays. Evidence of anti-D immunization in patients with D-negativity who have received DEL-variant blood units has been reported in various populations. This observation has prompted the need for genetic epidemiological and clinical data on the DEL variant in the development of DEL molecular diagnostic testing. This review highlights the molecular features of the DEL variant, the clinical consequences of DEL-blood transfusion, and current approaches for detection of the DEL-variant for donor screening and transfusion. PMID:25316658

  7. Comprension de los conceptos de los enlaces ionico y covalente en estudiantes universitarios del primer curso de quimica general

    NASA Astrophysics Data System (ADS)

    Ballesteros Benavides, Maria Elvira

    Para este trabajo utilizamos el estudio de casos cualitativo que se llevo a cabo en una universidad privada de Puerto Rico. Empleamos como unidad de analisis el concepto de enlace quimico, ionico y covalente. Los participantes fueron los estudiantes de la seccion nocturna del curso de Quimica General I. La investigacion se desarrollo por medio de dos entrevistas de persona a persona, observaciones de las expresiones no verbales y la hoja de identificacion de conceptos. Para la triangulacion tomamos en consideracion las preconcepciones erroneas, las concepciones alternativas y el mapa de conceptos de cada participante. Preparamos un mapa de conceptos para el enlace quimico validado por un comite de expertos. Tambien, elaboramos los mapas de conceptos de los participantes que sirvieron para varios propositos: conocer la estructura conceptual, expresar los logros, hacer comparaciones e identificar la presencia de concepciones alternativas. Entre los hallazgos encontramos que todos los participantes poseen conocimiento previo de los enlaces quimicos ionico y covalente y dentro de ese conocimiento existen preconcepciones erroneas mas numerosas para el enlace ionico. Al principio del semestre el 50% de los participantes demostraron tener "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente. Al finalizar el semestre encontramos en el 40% de los participantes concepciones alternativas tanto para el enlace ionico como para el covalente y el 90% no lograron distinguir un enlace del otro. Nuestras conclusiones fueron que los participantes sin distincion del aprovechamiento academico demostraron tener la tendencia de "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente, presentaron dificultad al integrar los conceptos de los enlaces quimicos ionico y covalente que se pusieron de manifiesto al dar los ejemplos. Las preconcepciones erroneas contribuyen en el desarrollo de las concepciones alternativas. Ademas, los

  8. Surface phonon polariton characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure.

    PubMed

    Ng, S S; Lee, S C; Bakhori, S K Mohd; Hassan, Z; Abu Hassan, H; Yakovlev, V A; Novikova, N N; Vinogradov, E A

    2010-05-10

    Surface phonon polariton (SPP) characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure are investigated by means of p-polarized infrared (IR) attenuated total reflection spectroscopy. Two absorption dips corresponding to In(0.04)Al(0.06)Ga(0.90)N SPP modes are observed. In addition, two prominent dips and one relatively weak and broad dip corresponding to the Al(2)O(3) SPP mode, In(0.04)Al(0.06)Ga(0.90)N/Al(2)O(3) interface mode, and Al(2)O(3) bulk polariton mode, respectively, are clearly seen. No surface mode feature originating from the AlN layer is observed because it is too thin. Overall, the observations are in good agreement with the theoretical predictions. PMID:20588890

  9. Formation of gamma'-Ni3Al via the Peritectoid Reaction: gamma plus beta (+Al2O3) equals gamma'(+Al2O3)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma'-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3) = gamma + beta (+ Al2O3), at 1640 plus or minus 1 K and a liquid composition of 24.8 plus or minus 0.2 at.%Al (at an unknown oxygen content). The {gamma + beta + Al2O3} phase field is stable over the temperature range 1633 - 1640 K, and gamma'-Ni3Al forms via the peritectiod, gamma + beta (+ Al2O3) = gamma'(+ Al2O3), at 1633 plus or minus 1 K. This behavior is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma'-Ni3Al phase field.

  10. Formation of gamma(sup prime)-Ni3Al via the Peritectoid Reaction: gamma + beta (+ Al2O3)=gamma(sup prime)(+ Al2O3)

    NASA Technical Reports Server (NTRS)

    Copeland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8-32 at.%Al and temperature range T=1400-1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma(sup prime)-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3)=gamma + Beta(+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%al (at an unknown oxygen content). The {gamma + Beta (+Al2O3} phase field is stable over the temperature range 1633-1640 K, and gamma(sup prime)-Ni3Al forms via the peritectoid, gamma + Beta (+ Al2O3)=gamma(sup prime) (+ Al2O3), at 1633 +/- 1 K. This behavior is consistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(sup prime)-Ni2Al phase field.

  11. Al/sub 2/O/sub 3/ adherence on CoCrAl alloys

    SciTech Connect

    Kingsley, L.M.

    1980-04-01

    Adherence of protective oxides on NiCrAl and CoCrAl superalloys has been promoted by a dispersion of a highly oxygen reactive element or its oxide being produced within the protection system. Two aspects of this subject are investigated here: the use of Al/sub 2/O/sub 3/ as both the dispersion and protective oxide; and the production of an HfO/sub 2/ dispersion while simultaneously aluminizing the alloy. It was found that an Al/sub 2/O/sub 3/ dispersion will act to promote the adherence of an external scale of Al/sub 2/O/sub 3/ to a degree comparable to previously tested dispersions and an HfO/sub 2/ dispersion comparable to that produced by a Rhines pack treatment is produced during aluminization.

  12. CVD Fiber Coatings for Al2O3/NiAl Composites

    NASA Technical Reports Server (NTRS)

    Boss, Daniel E.

    1995-01-01

    While sapphire-fiber-reinforced nickel aluminide (Al2O3/NiAl) composites are an attractive candidate for high-temperature structures, the significant difference in the coefficient of thermal expansion between the NiAl matrix and the sapphire fiber creates substantial residual stresses in the composite. This study seeks to produce two fiber-coating systems with the potential to reduce the residual stresses in the sapphire/NiAl composite system. Chemical vapor deposition (CVD) was used to produce both the compensating and compliant-fiber coatings for use in sapphire/NiAl composites. A special reactor was designed and built to produce the FGM and to handle the toxic nickel precursors. This process was successfully used to produce 500-foot lengths of fiber with coating thicknesses of approximately 3 microns, 5 microns, and 10 microns.

  13. In situ microscopy of rapidly heated nano-Al and nano-Al/WO3 thermites

    NASA Astrophysics Data System (ADS)

    Sullivan, Kyle T.; Chiou, Wen-An; Fiore, Richard; Zachariah, Michael R.

    2010-09-01

    The initiation and reaction mechanism of nano-Al and nano-Al thermites in rapid heating environments is investigated in this work. A semiconductor-based grid/stage was used, capable of in situ heating of a sample from room temperature to 1473 K, and at a rate of 106 K/s, inside an electron microscope. Nano-Al was rapidly heated in a transmission electron microscope, and before and after images indicate that the aluminum migrates through the shell, consistent with a diffusion-based mechanism. A nano-Al/WO3 composite was then heated in a scanning electron microscope. The results indicate that a reactive sintering mechanism is occurring for the nano-Al/WO3 thermite, as the products are found to be in surface contact and significantly deformed after the heating pulse.

  14. Preparation, structure and mechanical properties of RuAl and (Ru,Ni)Al alloys

    SciTech Connect

    Sabariz, A.L.R.; Taylor, G.

    1997-12-31

    The intermetallic compound, RuAl with B2 CsCl type structure, has been shown to possess room-temperature toughness and plasticity. NiAl also forms a B2 compound and it is claimed that a pseudo-binary compound, (Ru,Ni)Al, may be formed because the difference in lattice parameter between the two binary phases is slight. In this work a study has been made of the mechanical properties of some polycrystalline compounds, across the RuAl-(Ru,Ni)Al pseudo-binary, prepared from high-purity elemental powders. Compressive yield stresses were measured between room-temperature and 900 C, and the mechanisms of plastic flow are discussed in relation to the dislocation structures observed by TEM. Hot-microhardness tests were made to provide an indication of the effect of solid-solution hardening.

  15. 1300 K compressive properties of a reaction milled NiAl-AlN composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Arzt, Eduard; Luton, Michael J.

    1990-01-01

    When B2 crystal-structure nickel aluminide is subjected to high-intensity mechanical ball milling in a liquid nitrogen bath, or 'cryomilling', an NiAl composite is obtained which contains about 10 vol pct AlN particles. This composition arises from the incorporation of N during cryomilling; during subsequent thermomechanical processing, the N reacts with Al. While compressive testing of extruded or isostatically pressed specimens at 1300 K indicated that strength at relatively fast strain rates is slightly dependent on consolidation method, slower strain rates indicate no clear dependency on densification technique: four different consolidation methods were found to yield similar creep strengths. The creep properties of NiAl-AlN are similar to those of the single-crystal Ni-base superalloy NASAIR 100.

  16. Temperature dependence of the activity of Al in dilute Ni(Al) solid solutions

    SciTech Connect

    Jiang Yong; Smith, J. R.; Evans, A. G.

    2006-12-01

    Activities of dilute Al solid solutions in Ni are determined from a first-principles approach. Both thermal lattice vibration and electronic contributions to free energies are considered and compared. Vibrational contributions tend to dominate the temperature dependencies of the free energies, though electron thermal effects are significant. Calculations show opposing temperature trends for the formation enthalpies and entropies, leading to a partial cancellation of their role in the overall energetics. Nevertheless, their remaining temperature effects are strong. Over the temperature range, 400 KAl activity coefficient varies by 15 orders of magnitude, due to the relative strength of Al-Ni and Al-Al bonds. The Ni activity coefficient only varies less than 4% over the same range. Calculational results compare well with available experimental data. The thermodynamic principles elucidated from the calculations are used to provide a fundamental interpretation.

  17. 26Al+p elastic and inelastic scattering reactions and galactic abundances of 26Al

    NASA Astrophysics Data System (ADS)

    Pittman, S. T.; Bardayan, D. W.; Chae, K. Y.; Chipps, K. A.; Jones, K. L.; Kozub, R. L.; Matei, C.; Matos, M.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Parker, P. D.; Peters, W. A.; Shriner, J. F., Jr.; Smith, M. S.

    2012-06-01

    Galactic 26Al is the first radioactive nucleus to be positively identified by γ-ray astronomy with detection of the 1.809 MeV γ ray associated with its decay. This nucleus is destroyed in astrophysical environments in the 26Al(p,γ)27Si and inelastic 26Al+p scattering reactions where properties of 27Si levels determine reaction rates. To investigate these properties, elastic and inelastic 26Al+p scattering reactions were measured between Ec.m. = 0.5-1.5 MeV at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). A candidate for a new resonance in the 26Al(p,γ)27Si reaction was identified. Upper limits were also set on the strengths of postulated resonances and on the cross section of the inelastic reaction, but there is little effect on current reaction rate calculations.

  18. Effect of stress on the Al composition evolution in AlGaN grown using metal organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    He, Chenguang; Qin, Zhixin; Xu, Fujun; Zhang, Lisheng; Wang, Jiaming; Hou, Mengjun; Zhang, Shan; Wang, Xinqiang; Ge, Weikun; Shen, Bo

    2016-05-01

    Two series of AlGaN samples with different stresses were designed to investigate the effect of stress on the Al composition. X-ray diffraction reciprocal space mapping (XRD RSM) demonstrated that the AlGaN epilayers with different stresses have large Al composition differences despite the same growth conditions. The largest Al composition difference reached up to 21.3%, which was also confirmed using secondary ion mass spectroscopy (SIMS). This result is attributed to a large stress discrepancy in the AlGaN epilayers. Finally, the dependences of the solid-phase Al composition on the gas-phase Al composition under different stresses were systematically analyzed.

  19. Equilibrium point defects in intermetallics with the [ital B]2 structure: NiAl and FeAl

    SciTech Connect

    Fu, C.L.; Ye, Y.; Yoo, M.H. ); Ho, K.M. )

    1993-09-01

    Equilibrium point defects and their relation to the contrasting mechanical behavior of NiAl and FeAl are investigated. For NiAl, the defect structure is dominated by two types of defects---monovacancies on the Ni sites and substitutional antisite defects on the Al sites. The defect structure of FeAl differs from that of NiAl in the occurrence of antisite defects at the transition-metal sites for Al-rich alloys and the tendency for vacancy clustering. The strong ordering (and brittleness) of NiAl is attributed mainly to the difference in atomic size between constituent atoms.

  20. Wear characteristics of Al-AlN composites produced in-situ by nitrogenation

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Jena, S. K.; Patnaik, S. C.; Swain, P. K.; Majhi, J.

    2015-02-01

    In the present scenario most of the parts used in automobile and aerospace industries are made of composites. Aluminium metal has a very high strength to weight ratio. Al-AlN metal matrix composites have excellent mechanical properties like good wear resistance, high hardness and high strength to weight ratio which are obtained from low density of aluminium and high hardness and wear resistance of AlN. Therefore, use of Al-AlN MMC leads to advantages in automobile industries as it reduces fuel consumption and gives better structural strength. The composites can be produced ex-situ by introducing AlN as reinforcement into the metal matrix and in- situ by nitrogenation process. In the present process Al-AlN composites were fabricated by treating molten aluminium with a mixture of CaO and NH4Cl and held at temperature range at 750-930°C and then cast into a metal mould. Addition of CaO to NH4Cl is found to have a more pronounced effect as a nitrogenation agent in comparison with NH4Cl in the molten aluminium in the temperature range of 700- 1000°C. Castings of aluminium and Al-AlN composites were prepared by mixing different ratios of aluminium and NH4Cl, at different casting temperatures and holding time. Wear resistance and hardness of the samples were determined, and microstructure studies were carried out. The composite formed using higher amount of NH4Cl had higher hardness and wear resistance.

  1. 64. F.W.H., photographer May 21, 1930 VIEW OF ROAD ALONG ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    64. F.W.H., photographer May 21, 1930 VIEW OF ROAD ALONG COASTLINE, DEL NORTE COUNTY, SECTION B, HIGHWAY 1. 1-DN 1B #54, F.W.H., 5-21-30. Stamped office copy. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  2. 77 FR 77007 - Transfer of Land to the Department of Interior

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... Redwood Purchase Unit, California Humboldt Meridian, Del Norte County, California T.13 N., R. 1 E. Sec. 3... the United States of America by deed dated November 3, 1970, and recorded January 3, 1971, on pages 7... States of America by the County of Del Norte, by deed dated August 10, 1970, and recorded August 25,...

  3. Microstructure of Ni-Al powder and Ni-Al composite coatings prepared by twin-wire arc spraying

    NASA Astrophysics Data System (ADS)

    Wang, Ji-xiao; Wang, Gui-xian; Liu, Jing-shun; Zhang, Lun-yong; Wang, Wei; Li, Ze; Wang, Qi-xiang; Sun, Jian-fei

    2016-07-01

    Ni-Al powder and Ni-Al composite coatings were fabricated by twin-wire arc spraying (TWAS). The microstructures of Ni-5wt%Al powder and Ni-20wt%Al powder were characterized by scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the obtained particle size ranged from 5 to 50 μm. The morphology of the Ni-Al powder showed that molten particles were composed of Ni solid solution, NiAl, Ni3Al, Al2O3, and NiO. The Ni-Al phase and a small amount of Al2O3 particles changed the composition of the coating. The microstructures of the twin-wire-arc-sprayed Ni-Al composite coatings were characterized by SEM, EDS, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that the main phase of the Ni-5wt%Al coating consisted of Ni solid solution and NiAl in addition to a small amount of Al2O3. The main phase of the Ni-20wt%Al coating mainly consisted of Ni solid solution, NiAl, and Ni3Al in addition to a small amount of Al and Al2O3, and NiAl and Ni3Al intermetallic compounds effectively further improved the final wear property of the coatings. TEM analysis indicated that fine spherical NiAl3 precipitates and a Ni-Al-O amorphous phase formed in the matrix of the Ni solid solution in the original state.

  4. Thermodynamics and Kinetics of the Formation of Al2O3/ MgAl2O4/MgO in Al-Silica Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Sreekumar, V. M.; Ravi, K. R.; Pillai, R. M.; Pai, B. C.; Chakraborty, M.

    2008-04-01

    The formation of Al2O3, MgAl2O4, and MgO has been widely studied in different Al base metal matrix composites, but the studies on thermodynamic aspects of the Al2O3/ MgAl2O4/MgO phase equilibria have been limited to few systems such as Al/Al2O3 and Al/SiC. The present study analyzes the Al2O3/MgAl2O4 and MgAl2O4/MgO equilibria with respect to the temperature and the Mg content in Al/SiO2 system using an extended Miedema model. There is a linear and parabolic variation in Mg with respect to the temperature for MgAl2O4/MgO and Al2O3/MgAl2O4 equilibria, respectively, and the influence of Si and Cu in the two equilibria is not appreciable. The experimental verification has been limited to MgAl2O4/MgO equilibria due to the high Mg content (≥0.5 wt pct) required for composite processing. The study has been carried out on two varieties of Al/SiO2 composites, i.e., Al/Silica gel and Al/Micro silica processed by liquid metallurgy route (stir casting route). MgO is found to be more stable compared to MgAl2O4 at Mg levels ≥5 and 1 wt pct in Al/Silica gel and Al/Micro silica composites, respectively, at 1073 K. MgO is also found to be more stable at lower Mg content (3 wt pct) in Al/Silica gel composite with decreasing particle size of silica gel from 180 micron to submicron and nanolevels. The MgO to MgAl2O4 transformation has taken place through a series of transition phases influenced by the different thermodynamic and kinetic parameters such as holding temperature, Mg concentration in the alloy, holding time, and silica particle size.

  5. Bierman {ital et al.}Reply:

    SciTech Connect

    Bierman, J.D.; Chan, P.; Liang, J.F.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R.

    1997-05-01

    reply to the Comment by C.H.Dasso et al., Phys. Rev. Lett. 78,XXX(1997). A Reply to the Comment by C.H. Dasso and J. Fern{acute a}ndez-Niello. {copyright} {ital 1997} {ital The American Physical Society}

  6. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  7. Electron impact exctation of Al X

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti; Keenan, Francis

    2013-05-01

    Emission lines of Al ions, including Al X, are important for the modeling and diagnostics of lasing, fusion and astrophysical plasmas, for which atomic data are required for a variety of parameters, such as energy levels, radiative rates (A- values), and excitation rates or equivalently the effective collision strengths (Υ), which are obtained from the electron impact collision strengths (Ω). Experimentally, energy levels are available for Al X on the NIST website, but there is paucity for accurate collisional atomic data. Therefore, here we report a complete set of results (namely energy levels, radiative rates, and effective collision strengths) for all transitions among the lowest 98 levels of Al X. These levels belong to the (1s2) 2s2, 2s2p, 2p2, 2s3 l, 2p3 l, 2s4 l, and 2p4 l configurations. Finally, we also report the A- values for four types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2), because these are also required for plasma modeling. For our calculations of wavefunctions, we have adopted the fully relativistic GRASP code, and for the calculations of Ω, the Dirac atomic R-matrix code (DARC) of PH Norrington and IP Grant. Additionally, parallel ca

  8. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  9. Quantum Criticality in YFe2Al10

    NASA Astrophysics Data System (ADS)

    Gannon, William; Wu, Liusuo; Zaliznyak, Igor; Qiu, Yiming; Rodriguez-Rivera, Jose; Aronson, Meigan

    Quantum criticality has been studied in many systems, but there are few systems where observed scaling can be unified with a critical free energy F, or where the critical exponents form the basis for QC universality classes. We have identified a new layered material YFe2Al10 that shows remarkably strong QC behavior, where the scaling properties of the magnetic susceptibility and specific heat are consistent with the same F. Recent neutron scattering results paint a remarkable picture of the QC fluctuations in YFe2Al10. In contrast to classical transitions, where fluctuations are relatively long ranged and inelastic scattering is observed at a magnetic zone center, in YFe2Al10 the scattering is independent of wave vector in the critical plane, indicating that the fluctuations are spatially localized, while out of plane scattering indicates that the interplaner interactions are restricted to nearest neighbors. The dynamical susceptibility χ'' ~=E-2 , and is wholly temperature independent, indicating that E/T scaling is present, the signature of QC fluctuations. These results hint that the the criticality in YFe2Al10 is local, which until now has only been found in a few f-electron based compounds.

  10. Kinematics of Disease Progression in Bulbar ALS

    PubMed Central

    Yunusova, Yana; Green, Jordan; Lindstrom, Mary; Ball, Laura; Pattee, Gary; Zinman, Lorne

    2009-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar Amyotrophic Lateral Sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech performance such as speaking rate and speech intelligibility. Movements of the lip and jaw were quantified with respect to their size (i.e., path distance measure), speed, and duration. The data revealed several changes in lip and jaw movement that coincided with ALS progression. In two out of three speakers, the changes in measures of path distance and speed anticipated the drop in speech intelligibility by approximately 3 months. With disease progression, increases in movement duration coincided with declines in speech intelligibility. Overall, the movement measures appeared to be sensitive to disease progression in ALS. Learning outcomes By the end of the manuscript, the reader should be able to: (1) describe the changes that occur in articulatory movements of the jaw and lower lip in ALS; (2) understand the relationship between physiologic measures of movement and speech intelligibility and speaking rate; (3) identify critical points in the disease progression and understand which quantitative measures reveal the state of the bulbar system at these time points. PMID:19683250

  11. Cryptanalysis on Cheng et al. protocol

    NASA Astrophysics Data System (ADS)

    Thakur, Tejeshwari

    2016-06-01

    Deployment of new node in any wireless sensor network is a sensitive task. This is the reason why, an Access Control Protocol is required in WSN. In this paper, we demonstrate that Access Control Protocol proposed by Cheng et al.[1] for Wireless Sensor Network is insecure. The reason is that this protocol fails to resist the active attack.

  12. U-ALS: A Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Piovesan, Sandra Dutra; Passerino, Liliana Maria; Medina, Roseclea Duarte

    2012-01-01

    The diffusion of the use of the learning virtual environments presents a great potential for the development of an application which meet the necessities in the education area. In view of the importance of a more dynamic application and that can adapt itself continuously to the students' necessities, the "U-ALS" (Ubiquitous Adapted Learning…

  13. Al-Ghazali on Moral Education

    ERIC Educational Resources Information Center

    Alavi, Hamid Reza

    2007-01-01

    Al-Ghazali (1058-1111 CE) is probably the most influential scholar, philosopher, theologian, legal expert, religious reformer and mystic in the history of Islam. Although he wrote extensively about education, and particularly about moral education, this writing is scattered through a number of different works and has received less scholarly…

  14. 75 FR 26814 - Alabama Disaster #AL-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00031 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  15. 76 FR 29810 - Alabama Disaster #AL-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00037 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  16. 75 FR 474 - Alabama Disaster #AL-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  17. 78 FR 4967 - Alabama Disaster #AL-00046

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00046 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of ALABAMA dated...

  18. 76 FR 27141 - Alabama Disaster # AL-00036

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00036 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  19. 78 FR 22361 - Alabama Disaster #AL-00049

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00049 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  20. 75 FR 26813 - Alabama Disaster #AL-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00029 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  1. 77 FR 60003 - Alabama Disaster #AL-00044

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00044 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  2. 77 FR 7227 - Alabama Disaster #AL-00040

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00040 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  3. 75 FR 1420 - Alabama Disaster # AL-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00025 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  4. 76 FR 62481 - Incapital LLC, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-07

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Incapital LLC, et al.; Notice of Application September 30, 2011. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of application for an order under section 12(d)(1)(J) of...

  5. 78 FR 26100 - Alabama Disaster #AL-00050

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00050 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  6. SPI measurements of Galactic 26Al

    NASA Astrophysics Data System (ADS)

    Diehl, R.; Knödlseder, J.; Lichti, G. G.; Kretschmer, K.; Schanne, S.; Schönfelder, V.; Strong, A. W.; von Kienlin, A.; Weidenspointner, G.; Winkler, C.; Wunderer, C.

    2003-11-01

    The precision measurement of the 1809 keV gamma-ray line from Galactic 26Al is one of the goals of the SPI spectrometer on INTEGRAL with its Ge detector camera. We aim for determination of the detailed shape of this gamma-ray line, and its variation for different source regions along the plane of the Galaxy. Data from the first part of the core program observations of the first mission year have been inspected. A clear detection of the 26Al line at =~ 5-7 sigma significance demonstrates that SPI will deepen 26Al studies. The line intensity is consistent with expectations from previous experiments, and the line appears narrower than the 5.4 keV FWHM reported by GRIS, more consistent with RHESSI's recent value. Only preliminary statements can be made at this time, however, due to the multi-component background underlying the signal at =~ 40 times higher intensity than the signal from Galactic 26Al.

  7. Al/Cl2 molten salt battery

    NASA Technical Reports Server (NTRS)

    Giner, J.

    1972-01-01

    Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

  8. Correction to Rothermund et al. (2005)

    ERIC Educational Resources Information Center

    Rothermund, Klaus; Wentura, Dirk; De Houwer, Jan

    2005-01-01

    This article reports an error in the article "Retrieval of Incidental Stimulus-Response Associations as a Source of Negative Priming" by Rothermund et al. ("Journal of Experimental Psychology: Learning, Memory, and Cognition," Vol 31(3) May 2005, 482-495). Table 1 (p. 484) was incorrectly typeset. The correct layout is provided. (The following…

  9. Joint SSRTNet/ALS-MES Workshop report

    SciTech Connect

    Shuh, David; Van Hove, Michel

    2001-11-30

    This joint workshop brought together experimentalists and theorists interested in synchrotron radiation and highlighted subjects relevant to molecular environmental science (MES). The strong mutual interest between the participants resulted in joint sessions on the first day, followed by more specialized parallel sessions on the second day. Held in conjunction with the Advanced Light Source (ALS) Users' Association Annual Meeting at the Lawrence Berkeley National Laboratory (Berkeley Lab), the Synchrotron Radiation Research Theory Network (SRRTNet) workshop was co-organized by Michel Van Hove (Berkeley Lab and University of California, Davis) and Andrew Canning (Berkeley Lab), while David Shuh (Berkeley Lab) organized the ALS-MES workshop. SRRTNet is a global network that promotes the interaction of theory and experiment (http://www.cse.clrc.ac.uk/Activity/SRRTnet). The ALS-MES project is constructing Beamline 11.0.2.1-2, a new soft x-ray beamline for MES investigations at photon energies from 75 eV to 2 keV, to provide photons for wet spectroscopy end stations and an upgraded scanning transmission x-ray microscope (STXM). The ALS-MES beamline and end stations will be available for users in the late fall of 2002.

  10. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  11. Thermal mixing of Al-Fe multilayers

    NASA Astrophysics Data System (ADS)

    Meyer, M.; Mendoza Zélis, L.; Sánchez, F. H.; Traverse, A.

    1994-12-01

    Al-Fe multilayers have been mixed by thermal treatment and their evolution followed by conversion electron Mössbauer spectroscopy. The initial and final states have been characterized by Rutherford backscattering spectrometry. The results are compared with those previously obtained in the ion beam mixing of similar systems.

  12. Hydrogen Solubility in Al-bearing Perovskite

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Krawczynski, M. J.; Fei, Y.

    2005-12-01

    It is generally accepted that silicate perovskite is the dominant mineral in the Earth's lower mantle. Previous studies have been completed to determine the physical and chemical characteristics of the pure end-member MgSiO3. Recent studies have shown that the addition of Al to MgSiO3 can have a significant effect on the material properties of the mineral, such as compressibility, and defect structure, as well as a great potential to dissolve water. We have synthesized Al-bearing perovskite samples under hydrous conditions in a multi-anvil apparatus at pressures ranging from 23-26 GPa and 1800oC. The starting materials consisted of brucite and silica powders mixed together and finely ground in a 1:1 molar ratio, with subsequent addition of Al2O3 powder at 2wt% intervals from 0%-6%. The mixed powders were tightly packed in Au capsules, housed in BN sleeves, and loaded into standard 8/3 multi-anvil assemblies. The experiments were brought to the appropriate pressure conditions for solubility of the different Al2O3 contents. The resulting perovskite crystals range in size from <20 microns to >100 microns in size. Their major element chemistry has been characterized by EPMA, and the H content of some samples has been measured by secondary ion mass spectrometry using a 6f Cameca ion microprobe and is substantial (>1200ppm in some samples). In this study, we correlate H content in the perovskites with Al concentration, and discussion follows on what effects this may have on potential substitution mechanisms, and correlated formation of oxygen vacancies, as well as water storage in the mantle, oxygen diffusion, and the potential of an oxygen ionic diffusion contribution to electrical conductivity in the mantle.

  13. Calculation of the structure of the Al(331) stepped surface

    SciTech Connect

    Nelson, J.S.; Feibelman, P.J. )

    1992-04-06

    Car-Parinello-like calculations have been used to compute the relaxation of the Al(331) surface, with results that are in remarkable agreement with the low-energy electron-diffraction analysis of Adams and So( )renson. Rapid screening of the steps on Al(331) is illustrated by comparing its charge density and relaxations to those of Al(110) and Al(111).

  14. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids have been observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. It was postulated that the voids resulted from an excess number of oxygen vacancies near the oxide-metal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidations of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al,Cr)2O3 and Ni(Al,Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationships between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  15. Electrical defects in AlGaN and InAlN

    NASA Astrophysics Data System (ADS)

    Johnstone, D.; Leach, Jacob H.; Kovalskii, Vladimir A.; Fan, Qian; Xie, Jingqiao; Morkoç, Hadis

    2009-02-01

    Compound semiconductors based on GaN have multiple functional applications. Useful compositions include GaN, and ternary and quaternary compositions of (AlGaIn)N. Defects arising from lattice mismatch, point defects, or impurities may act as electrical trapping centers and degrade device efficiency. Current-voltage, capacitance-voltage, thermal admittance spectroscopy (TAS), and deep level transient spectroscopy (DLTS) measurements are applied to characterize the defects in Al0.40Ga0.80N and In0.18Al0.82N in this report. Broad peaks with a shoulder at high temperature dominate the DLTS spectra in each of the materials. An acceptor trap associated with a dislocation appears at 340 K in AlGaN. The defect has an energy of 0.2 eV and capture cross section of 10-21 cm2. A second trap at 0.35 eV, 10-14 cm2 appears in the TAS measurements in addition to the trap at 0.2 eV. Defects in InAlN are dominated by a peak near 150 K. Two traps appear in the TAS measurements. Both traps in the InAlN are acceptors, based on a lack of field dependent emission rates using double pulse DLTS (DDLTS). The two energy levels in InAlN appear to be coupled, with only one state occupied at a time.

  16. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids were observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. The voids resulted from an excess number of oxygen vacancies near the oxidemetal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidation of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al, Cr)2O3 and Ni(Al, Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationship between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  17. Thermoelectric Powers of Cells With NaF-AlF3-Al2O3 Melts

    NASA Astrophysics Data System (ADS)

    Flem, Belinda E.; Xu, Qian; Kjelstrup, Signe; Sterten, Åsmund

    2001-07-01

    A thermodynamic description of the Peltier heat at the aluminum and the oxygen electrode in the system NaF-AlF3-Al2O3 is given. The thermoelectric power in melts with molar ratios n NaF/n AlF3 from 3.0 to 1.0, saturated with alumina are measured. Seebeck coefficients for molten fluoride electrolytes saturated with alumina, electrolytes that are relevant for aluminum electrowinning electrolysis cells, are reported. The results allow determinations of Peltier heats of aluminum, oxygen and carbon electrodes in NaF-AlF3 electrolytes saturated with alumina. For molar ratios of n NaF/n AlF3 between 2.6 and 1.2, there is a Peltier heating of the aluminum cathode. This heating is in the same order of magnitude as the electrolyte Joule heat, when the current density is 0.7 A cm-2. For molar ratio n NaF/n AlF3 equal to 1.0 the Peltier effect at the aluminum electrode approaches zero. From theoretical considerations we expect a drop also for molar ratio 3.0. For the anode we report a Peltier cooling that is larger than the heat produced by the anodic overvoltage, in melts with NaF/AlF3 molar ratio between 2.6 and 1.2 saturated with alumina.

  18. High noise suppression using magnetically isotropic (CoFe-AlN)/(AlN) multilayer films

    NASA Astrophysics Data System (ADS)

    Kijima, Hanae; Ohnuma, Shigehiro; Masumoto, Hiroshi; Shimada, Yutaka; Endo, Yasushi; Yamaguchi, Masahiro

    2015-05-01

    Magnetically isotropic (CoFe-AlN)n/(AlN)n+1 multilayer films, in which the number of CoFe-AlN magnetic layers n ranged from 1 to 27, were prepared by radio frequency sputtering to achieve noise suppression at gigahertz frequencies. The soft CoFe-AlN magnetic layers consisted of nanometer-sized CoFe ferromagnetic grains embedded in an insulating AlN amorphous matrix, while the insulating AlN layers comprised AlN columnar crystals. All films showed a similar frequency dependence of permeability and ferromagnetic resonance of 1.7 GHz. Noise suppression was evaluated using a microstrip line as a noise source by determining the in-line conductive loss and the near-field intensity picked up by magnetic field detective probes. High noise suppression effects were observed in every direction in the film plane. Maximum noise suppression values amounted to 60% for the in-line conductive loss and -20 dB for the magnetic near-field intensity at around 1.7 GHz in the 27-layer film. These high-frequency noise suppression levels may be attributed to eddy current losses and ferromagnetic resonance.

  19. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA1

    PubMed Central

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma. Emily; Medina-Mora, Dra. Ma. Elena

    2010-01-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio. La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos. Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos. PMID:20830214

  20. del, Einstein, Mach, Gamow, and Lanczos: Gödel's remarkable excursion into cosmology

    NASA Astrophysics Data System (ADS)

    Rindler, Wolfgang

    2009-06-01

    This article is an expanded version of a talk given at the International Symposium Celebrating the 100th Birthday of Kurt Gödel (Vienna, 2006). It seeks to trace the path which led this preeminent mathematical logician to discover one of the famous results of General Relativity, the rotating Gödel Universe. This universe has some remarkable properties, which gave the philosophers plenty to worry about. It allows a person to travel into his own past, with all the ensuing causal paradoxes; it allows no unique temporal ordering of events; and though Gödel's Universe is rigid and infinite, the Foucault pendulum planes everywhere in it rotate in unison, a clear affront to adherents of Mach's Principle. We also discuss some lesser known precursors in the field, who just missed discovering Gödel's universe. While the article gives all the necessary derivations in simplified form (for example, of the metric and its geodesics), much of it should be accessible to the general reader, who can simply skip most of the mathematics. [Reprinted, with permission, from Kurt Gödel and the Foundations of Mathematics: Horizons of Truth, edited by Matthias Baaz, Christos H. Papadimitriou, Dana S. Scott, Hilary Putnam, and Charles L. Harper, Jr. (Cambridge U. P., New York, 2009).

  1. A 25-year replication of Katz et al.'s (1988) metaphor norms.

    PubMed

    Campbell, Spencer J; Raney, Gary E

    2016-03-01

    Research in metaphor processing has made extensive use of the normed metaphor database created by Katz, Paivio, Marschark, & Clark (Metaphor and Symbolic Activity, 3, 191-214, 1988). Because of the plasticity of figurative language, we conducted a renorming of selected metaphors from the database on a new student population. Correlations between Katz et al.'s and the present data showed that the pattern of responses has remained highly consistent across time and populations. The consistency of the normative ratings allows us to be confident in future research that will use the Katz et al. collection. PMID:25772671

  2. Ferromagnetic ordering in NpAl2: Magnetic susceptibility and 27Al nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Martel, L.; Griveau, J.-C.; Eloirdi, R.; Selfslag, C.; Colineau, E.; Caciuffo, R.

    2015-08-01

    We report on the magnetic properties of the neptunium based ferromagnetic compound NpAl2. We used magnetization measurements and 27Al NMR spectroscopy to access magnetic features related to the paramagnetic and ordered states (TC=56 K). While very precise DC SQUID magnetization measurements confirm ferromagnetic ordering, they show a relatively small hysteresis loop at 5 K reduced with a coercive field HCo~3000 Oe. The variable offset cumulative spectra (VOCS) acquired in the paramagnetic state show a high sensitivity of the 27Al nuclei spectral parameters (Knight shifts and line broadening) to the ferromagnetic ordering, even at room temperature.

  3. Revisiting Deng et al.'s Multiparty Quantum Secret Sharing Protocol

    NASA Astrophysics Data System (ADS)

    Hwang, Tzonelih; Hwang, Cheng-Chieh; Yang, Chun-Wei; Li, Chuan-Ming

    2011-09-01

    The multiparty quantum secret sharing protocol [Deng et al. in Chin. Phys. Lett. 23: 1084-1087, 2006] is revisited in this study. It is found that the performance of Deng et al.'s protocol can be much improved by using the techniques of block-transmission and decoy single photons. As a result, the qubit efficiency is improved 2.4 times and only one classical communication, a public discussion, and two quantum communications between each agent and the secret holder are needed rather than n classical communications, n public discussions, and 3n/2 quantum communications required in the original scheme.

  4. Low cycle fatigue of FeAl(42 at. % Al) at room temperature

    SciTech Connect

    Hanes, D.B.; Gibala, R.

    1997-12-31

    The monotonic mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonic testing.

  5. Al-based metal matrix composites reinforced with nanocrystalline Al-Ti-Ni particles

    NASA Astrophysics Data System (ADS)

    Scudino, S.; Ali, F.; Surreddi, K. B.; Prashanth, K. G.; Sakaliyska, M.; Eckert, J.

    2010-07-01

    Al-based metal matrix composites containing different volume fractions of nanocrystalline Al70Ti20Ni10 reinforcing particles have been produced by powder metallurgy and the effect of the volume fraction of reinforcement on the mechanical properties of the composites has been studied. Room temperature compression tests reveal a considerable improvement of the mechanical properties as compared to pure Aluminum. The compressive strength increases from 155 MPa for pure Al to about 200 and 240 MPa for the samples with 20 and 40 vol.% of reinforcement, respectively, while retaining appreciable plastic deformation with a fracture strain ranging between 43 and 28 %.

  6. Adherent Al2O3 scales formed on undoped NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1987-01-01

    Changes in the spalling behavior of Al2O3 scales formed on an undoped NiCrAl alloy are described. Two samples of Ni-15Cr-13Al (wt pct), one a control and the other sanded, were subjected to 25 oxidation cycles. It is observed that adherent scales formed on the sanded sample; however, the control sample had speckled, spalled scales. The data reveal that the adherent scales are caused by repeated removal of surface layers after each oxidation cycle. It is determined that interfacial segregation of sulfur influences spallation and sulfur removal increases bonding. The effect of moisture on scale adhesions is investigated.

  7. Atomic layer epitaxy of AlAs and AlGaAs

    NASA Astrophysics Data System (ADS)

    Meguro, T.; Iwai, S.; Aoyagi, Y.; Ozaki, K.; Yamamoto, Y.; Suzuki, T.; Okano, Y.; Hirata, A.

    1990-01-01

    Atomic layer epitaxy (ALE) of AlAs and AlGaAs with metalorganic vapor-phase epitaxy (MOVPE) under Ar-ion laser irradiation has been successfully realized in a triethylaluminum (TEA)/AsH 3 system for the first time. Comparison with the growth characteristics of MOVPE with alternative feeding modes of TMA/AsH 3 and TEA/AsH 3 is discussed. Application to laser-ALE of AlGaAs using a triethylgallium (TEG)/TEA/AsH 3 system is also discussed.

  8. On the crack growth resistance and strength of the B2 iron aluminides Fe-40Al, Fe-45Al, and Fe-10Ni-40Al (at. %)

    SciTech Connect

    Schneibel, J.H.; Maziasz, P.J.

    1994-09-01

    The crack growth resistance and yield strength of the B2 iron aluminides Fe-40Al, Fe-45Al, are Fe-10Ni-40Al (at. %) have been investigated at room temperature laboratory air. After fast cooling from 1273 K, Fe-45Al and Fe-10Ni-40Al are much stronger than Fe-40Al, and exhibit considerably lower crack growth resistance. The crack growth resistance decreases with decreasing crack propagation velocity. Low crack propagation velocities favor intergranular fracture, whereas high velocities can lead to significant contributions from transgranular fracture. Boron additions to Fe-40Al and Fe-10Ni-40Al improve the crack growth resistance, reduce its dependence on the crack propagation velocity, and cause the path to be predominantly transgranular. In a plot of fracture toughness versus yield strength, the properties of the iron aluminides are similar to those of typical aluminum alloys.

  9. Density of Low-Temperature KF-AlF3 Aluminum Baths with Al2O3 and AlPO4 Additives

    NASA Astrophysics Data System (ADS)

    Vasková, Zuzana; Kontrík, Martin; Mlynáriková, Jarmila; Boča, Miroslav

    2015-02-01

    The density of the KF-AlF3 melts of various KF and AlF3 ratio with Al2O3 and AlPO4 addition has been measured using the Archimedean method. On the basis of the obtained density data the molar volumes of the melts were calculated. These molar volumes decrease with concentration of Al2O3 or AlPO4. In the system containing AlPO4, the relation between cryolite ratios (CRs) vs slopes of molar volume trend lines was identified with excellent correlation factor of R 2 = 0.9844, while in the system containing Al2O3 a discontinuity at CR = 2.5 can be observed.

  10. Procesamiento Digital de Imagenes del Cometa Halley

    NASA Astrophysics Data System (ADS)

    Ferrin, L.; Fuenmayor, F.; Naranjo, O.; Bulka, P.; Mendoza, C.

    1987-05-01

    Se reportan observaciones fotográficas del cometa Halley, obtenidas con los telescopios Schmidt de 1-m del CIDA, y de 35 cms de la ULA. Se hicieron exposiciones desde 2 segundos a 30 minutos y se utilizaron emulsiones IIa-O, 103a-F, y 103a-D, guladas manualmente 0 automaticámente. Las imágenes fueron digitalizadas con el microdensitómetro PDS, y procesadas con el sistema HACIENDA del CCIBM. Se experimentó con la Transformada de Fourier en dos dimensiones, y con la aplicación de filtros de paso alto y bajo. Se encontró que el metodo de "autocorrelación" es el mejor para separar "la vegetación" de "la montaña". Se aplicaron diversas técnicas a fin de cubrir ambos extremos: a) enfatizar detalles débiles en la cola, y b) penetrar en las regiones más intensas de la coma. Se lograron ambos objetivos. Detalles en la cola permitieron determinar velocidades de propagación de unos 50 a 90 kms/ seg. Se pudieron detectar no menos de tres perturbaciones en "Y", y una en 5? Co de Cisne). Se cree que las primeras están asociadas a eventos de desconexión. Se puede separar la cola de gas de la de polvo. Las fotos de color permiten enfatizar diferentes regiones espectrales con mayor claridad aún. El "balance" del color puede ser hecho con la computadora.

  11. [Assay of three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions by Al-Ferron timed spectrophotometry and demarcation of their time limits].

    PubMed

    Wang, Chen-yi; Zhang, Cai-hua; Bi, Shu-ping; Zhang, Zhen-chao; Yang, Wei-hua

    2005-02-01

    Al-Ferron timed spectrophotometry assay is a basic method in the study on the formation of polynuclear hydroxyl aluminum species and their transformation laws in aqueous systems. In actual working process, this methodology has some dogmatism and arbitrariness in the time limits demarcation of the three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions, which makes this kind of classification rougher, and the experimental results non-reproducible. The reason for this difference is that the specific species within Al(a), Al(b) and Al(c) have different reaction mechanism and dynamics, and that specific species of Al(b) having different OH/Al ratios have different reaction rates with ferron. In this paper, the ExpAssoc distribution was applied to quantitatively fit the Al-Ferron reaction dynamics curve, and the extrapolation method was used to survey the 1 min measured value [Al(a)] of monomeric Al, which is hard to obtain in manual manipulation. The time demarcation between Al(b) and Al(c) should reach the point of the experimental data curve up to horizontal platform. The microwave-radiated technology was used to fast assay the total aluminum concentration [Al(T)]. With these methods, the contents of monomeric Al(a), polynuclear Al(b) and gel Al(c) can be conveniently and quantitatively measured. It offers a novel method for surmounting the arbitrariness in the measurement of the three kinds of aluminum fractions and the repetitive calculation of Al(a) and Al(b). PMID:15852869

  12. Visualization of the Gödel universe

    NASA Astrophysics Data System (ADS)

    Buser, M.; Kajari, E.; Schleich, W. P.

    2013-01-01

    The standard model of modern cosmology, which is based on the Friedmann-Lemaître-Robertson-Walker metric, allows the definition of an absolute time. However, there exist (cosmological) models consistent with the theory of general relativity for which such a definition cannot be given since they offer the possibility for time travel. The simplest of these models is the cosmological solution discovered by Kurt Gödel, which describes a homogeneous, rotating universe. Disregarding the paradoxes that come along with the abolishment of causality in such space-times, we are interested in the purely academic question of how an observer would visually perceive the time travel of an object in Gödel's universe. For this purpose, we employ the technique of ray tracing, a standard tool in computer graphics, and visualize various scenarios to bring out the optical effects experienced by an observer located in this universe. In this way, we provide a new perspective on the space-time structure of Gödel's model.

  13. VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HOWLAND HILL ROAD, JEDEDIAH SMITH STATE PARK. CRESCENT CITY, DEL NORTH COUNTY, CALIFORNIA. LOOKING ESE. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  14. Characterization of Al30 in commercial poly-aluminum chlorohydrate by solid-state (27)Al NMR spectroscopy.

    PubMed

    Phillips, Brian L; Vaughn, John S; Smart, Scott; Pan, Long

    2016-08-15

    Investigation of commercially produced hydrolysis salts of aluminum by solid-state (27)Al NMR spectroscopy and size-exclusion chromatography (SEC) reveals well-defined and distinct Al environments that can be related to physicochemical properties. (27)Al MAS and MQ-MAS NMR spectroscopic data show that the local structure of the solids is dominated by moieties that closely resemble the Al30 polyoxocation (Al30O8(OH)56(H2O)26(18+)), accounting for 72-85% of the total Al. These Al30-like clusters elute as several size fractions by SEC. Comparison of the SEC and NMR results indicates that the Al30-like clusters includes intact isolated clusters, moieties of larger polymers or aggregates, and possibly fragments resembling δ-Al13 Keggin clusters. The coagulation efficacy of the solids appears to correlate best with the abundance of intact Al30-like clusters and of smaller species available to promote condensation reactions. PMID:27232539

  15. Synthesis and characterization of Al-Zn/Al2O3 nano-powder composites.

    PubMed

    Durai, T G; Das, Karabi; Das, Siddhartha

    2007-06-01

    Composites consisting of Al-Zn/Al2O3 have been synthesized using high energy mechanical milling. High energy ball milling increases the sintering rate of the composite powder due to increased diffusion rate. Owing to the finer microstructure, the hardness of the sintered composite produced by using the mechanically milled nanocomposite powder is significantly higher than that of the sintered composite produced by using the as-mixed powder. The mean crystallite size of the matrix has been determined to be 27 nm by Scherrer equation using X-ray diffraction data. The powders have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and differential thermal analysis (DTA). The effect of high-energy ball milling and subsequent annealing on a mixture of Al and ZnO has also been investigated. DTA result show that the reaction temperature of Al-ZnO decreases with the increase in the ball milling time. PMID:17654976

  16. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  17. Nonstatistical fluctuations for deep inelastic processes in {sup 27}Al+{sup 27}Al collisions

    SciTech Connect

    Berceanu, I.; Duma, M.; Moisa, D.; Petrovici, M.; Pop, A.; Simion, V.; Zoppo, A. Del; D'Erasmo, G.; Imme, G.; Lanzano, G.; Pagano, A.; Pantaleo, A.; Raciti, G.

    2006-08-15

    The excitation functions (EFs) for different fragments produced in the {sup 27}Al+{sup 27}Al dissipative collisions have been measured in steps of 250 keV in the incident energy range 122-132 MeV. Deep inelastic processes have been selected by integrating events on a total kinetic energy loss window of 12 MeV between 20 and 32 MeV. Large fluctuations are observed in all the studied EFs. Large-channel cross-correlation coefficients confirm the nonstatistical origin of these fluctuations. The energy autocorrelation function (EAF) shows damped oscillation structure as expected when a dinuclear system with a lifetime [{tau}=(5.1{+-}2.1){center_dot}10{sup -21}s], similar with its revolution period (T=4.9{center_dot}10{sup -21}sec), is formed. From the periodicity of the EAF oscillations, information on the deformation of the {sup 27}Al+{sup 27}Al dinucleus is inferred.

  18. Formation of AlN in laser ablated plasma of Al in nitrogen ambient

    NASA Astrophysics Data System (ADS)

    Thareja, Raj K.; Sharma, A. K.

    2005-05-01

    We report on spectroscopic investigations of interaction of an expanding laser ablated plume of aluminum and graphite with nitrogen gas and the formation of AlN and CN. AlN and CN bands are formed by reactive process of ablated aluminum and graphite in ambient nitrogen pressures of 70 and 0.1 Torr and laser fluence of 500 and 12 Jcm-2 respectively. Images of the expanding plasma plume were captured using ICCD to understand the role of vapor and shock temperature in the formation of AlN. Instability observed in laser ablated plume at later times attributed to Rayleigh-Taylor instability could be the cause for weak AlN band observed in the emission spectrum.

  19. Fabrication and properties of functionally graded NiAl/Al2O3 composites

    NASA Technical Reports Server (NTRS)

    Miller, D. P.; Lannutti, J. J.; Noebe, R. D.

    1993-01-01

    A modified sedimentation process was used in the production of a functionally gradient material (FGM), NiAl/Al2O3. A simple finite element model was used to guide our design and fabrication efforts by estimating residual stress states as a function of composite structure. This approach could lead to tailored designs that enhance or avoid specific residual stress states. Thermal cycling tests were factored into the model to predict time dependent or steady-state internal temperature and stress profiles. Four-point bend tests were conducted to establish the mechanical load-displacement behavior of a single interlayer FGM at room temperature, 800 and 1000 K. Room temperature bend strength of the FGM was 3-4 times that of the base NiAl. At elevated temperatures, composite fracture occurred in a gradual, noncatastrophic mode involving NiAl retardation of a succession of cracks originating in the alumina face.

  20. 'Abd al-Rahman al-Sufi's 3-Step Magnitude System

    NASA Astrophysics Data System (ADS)

    Hafez, Ihsan; Stephenson, F. Richard; Orchiston, Wayne

    'Abd al-Rahmān al-ūfī's Book of the Fixed Stars dates from around AD 964 and is one of the most important medieval Arabic treatises on astronomy. In this paper we begin with a very brief introduction to the Book of the Fixed Stars. This book contains an extensive star catalogue that lists star coordinates and magnitude estimates for all of the Ptolemaic stars. However, in his book al-hūfī utilized three distinct intermediate magnitude values whereas Ptolemy only mentioned two. We believe that al-hūfī used what we have termed a '3-step intermediate magnitude system,' which is more accurate than Ptolemy's 2-step intermediate system. In this paper we examine in detail the accuracy of this unique 3-step system in comparison with Ptolemy's and modern magnitude values.

  1. Al Knight-shift measurement in the superconducting state of UNi 2Al 3

    NASA Astrophysics Data System (ADS)

    Ishida, K.; Tou, H.; Tateiwa, N.; Kitaoka, Y.; Sato, K. N.; Aso, N.; Geibel, C.; Steglich, F.

    2003-05-01

    We report 27Al Knight-shift (27K) measurement on a single-crystal UNi2Al3 that reveals a coexistence of superconductivity and a spin-density-wave (SDW) type of magnetic ordering (TSDW=4.5 K). The spin part of 27K, 27Ks does not change down to 50 mK across the superconducting (SC) transition temperature Tc∼0.9 K. In contrast with the isostructural compound UPd2Al3 (Tc∼2 K), which was identified to be a spin-singlet d-wave superconductor, the behavior of 27K strongly supports that UNi2Al3 belongs to a class of spin-triplet SC pairing state superconductor.

  2. Local stress-induced effects on AlGaAs/AlOx oxidation front shape

    SciTech Connect

    Chouchane, F.; Almuneau, G. Arnoult, A.; Lacoste, G.; Fontaine, C.; Cherkashin, N.

    2014-07-28

    The lateral oxidation of thick AlGaAs layers (>500 nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized Al{sub x}Ga{sub 1−x}As/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.

  3. Interdiffusion in the Mg-Al system and Intrinsic Diffusion in (Al3Mg2) Phase

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S; Sohn, Yong Ho

    2011-01-01

    Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics -Al12Mg17 and -Al3Mg2, but not -phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  4. Morphology, geology and geochemistry of the "Salar del Gran Bajo del Gualicho" (Rio Negro, Argentina)

    USGS Publications Warehouse

    Angelucci, A.; Barbieri, M.; Brodtkorb, A.; Ciccacci, S.; Civitelli, G.; De Barrio, R.; Di, Filippo M.; Fredi, P.; Friedman, I.; Lombardi, S.; Schalamuk, A.I.; Toro, B.

    1996-01-01

    A multidisciplinary study of the Gran Bajo del Gualicho area (Rio Negro - Argentina) was carried out; the aim was to delineate its geological and geomorphological evolution and to estabilish the genesis of salts filling the depression. Climatic conditions were analized first to individuate their role in the present morphogenetic processes; moreover the main morphological features of present landscape were examined as well as the stratigraphy of the outcropping formations, and of the Gran Bajo del Gualicho Formation in particular. Finally, a possible geomorphological evolution of the studied area was traced. Geophysical analyses allowed to estabilish that the paleosurface shaped on the crystalline basement is strongly uneven and shows evidence of the strong tectonic phases it underwent. The result of isotope analyses confirmed that the salt deposits on the Gran Bajo del Gualicho bottom were produced by fresh water evaporation, while strontium isotope ratio suggested that such waters were responsible for solubilization of more ancient evaporitic deposits.

  5. A Description of Del Mod and Its Final Evaluation, Final Report, Volume I.

    ERIC Educational Resources Information Center

    Purnell, Charlotte H.; Bolig, John R.

    This monograph presents an overview of five Del Mod System final reports, comments by the project director, financial structure of the Del Mod System, and descriptions of Del Mod Projects. The Del Mod System was concerned with changing the science and mathematics education programs in the state of Delaware. Between 1970 and 1976, Del Mod conducted…

  6. Simulation of aluminothermic smelting of Al-Zr and Al-Zr-Mo-Sn alloys

    NASA Astrophysics Data System (ADS)

    Larionov, A. V.; Chumarev, V. M.; Udoeva, L. Yu.; Mansurova, A. N.; Rylov, A. N.; Raikov, A. Yu.; Aleshin, A. P.; Trubachev, M. V.

    2013-09-01

    Aluminothermic smelting of Al-Zr and Al-Zr-Mo-Sn alloys has been simulated in terms of thermodynamics. The thermodynamic properties of molybdenum and zirconium intermetallic compounds are calculated. It is demonstrated that, with consideration for their formation, the calculated compositions of aluminothermic blends and the forecasted extraction of target metals into an alloy are in good agreement with the data obtained during pilot tests.

  7. Alkali metal adsorption on Al(111)

    NASA Astrophysics Data System (ADS)

    Andersen, J. N.; Lundgren, E.; Nyholm, R.; Qvarford, M.

    1993-06-01

    The submonolayer adsorption of Na, K, Rb, and Cs on the Al(111) surface at 100 K and at room temperature is investigated by high resolution core level spectroscopy and low energy electron diffraction. It is found that the first alkali atoms on the surface adsorb at surface defects. At higher coverages, up to approximately one third of the maximum submonolayer coverage, alkali atoms adsorbed at defects coexist with a dispersed phase. At higher coverages island formation is found to occur for the majority of the systems. It is argued that all of the ordered structures formed at room temperature involve a disruption of the Al(111) surface in contrast to the situation at 100 K where the alkali atoms adsorb as adatoms.

  8. Forging of FeAl intermetallic compounds

    SciTech Connect

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L.; Schneibel, J.H.

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  9. Observable Proxies For 26 Al Enhancement

    SciTech Connect

    Fryer, Christopher L; Young, Patrick A; Ellinger, Carola I; Arnett, William D

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  10. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1979-01-01

    Cold pressing and sintering techniques were used to produce ceramic test specimens in which the major phase was either Si3N4 or a solid solution having the beta Si3N4 structure. Additional components were incorporated to promote liquid phase sintering. Glass and/or crystalline phase were consequently retained in boundaries between Si3N4 grains which largely determined the physical properties of the bodies. Systems investigated most extensively included R-Si-Al-O-N (R = rare earth element) Zr-Si-Al-O-N, Y-Si-Be-O-N, and R1-R2-Si-O-N. Room temperature and 1370 C modulus of ruptured, 1370 C creep, and oxidation behavior are discussed in terms of phase relationships in a parent quinery, and relavent oxide systems.

  11. Stress evolution during ultrasonic Al ribbon bonding

    NASA Astrophysics Data System (ADS)

    Ando, Masaya; Takashima, Kazumasa; Maeda, Masakatsu; Takahashi, Yasuo

    2014-08-01

    The present study reveals the stress distribution in the substrate during ultrasonic bonding. The deformations of the Si substrate, Al ribbon, and Al pad were numerically analyzed using a finite element method. Experimental observation of the interface using a highspeed video camera was also conducted to determine the actual interfacial slip amplitude. This amplitude becomes smaller than that of tool-tip with bonding time. It was suggested from the numerical simulations that frictional adhesion enhanced the friction force, resulting in an increase in the equivalent stress in the ribbon and pad. As a result, very large stresses occur in the substrate during ultrasonic bonding. These stresses evolve with the progress of ultrasonic bonding, i.e., frictional adhesion.

  12. 14th Annual ALS Users' Association meeting

    SciTech Connect

    Robinson, Art

    2001-11-29

    Sponsored by the Users' Executive Committee (UEC) and spread over three days from October 15-17, the fourteen annual ALS Users' Association Meeting featured an exceptional program with science as the main theme. While the first day was reserved for the traditional facility and Washington reports and for science highlights, the following two days, devoted to several workshops covering topics from theory to detectors, new experimental facilities, and forefront science, were strong draws. As a result, it should not be surprising that the number of registered attendees jumped to a record level of 352, more than 100 above the typical attendance in recent years. The successful commissioning of the long-awaited superconducting bend magnets, or superbends, in the ALS storage-ring lattice just before the meeting opened also helped stimulate interest.

  13. Antiferromagnetic behaviour of Tb2Al alloy

    NASA Astrophysics Data System (ADS)

    Rojas, D. P.; André, G.; Rodríguez Fernández, J.; Sánchez Marcos, J.; Fernández Barquín, L.; Echevarria, C.

    2011-10-01

    The structural, thermal and magnetic properties ol the Tb2Al alloy have been investigated by AC/DC magnetic susceptibility, specific heat, X-ray and neutron diffraction measurements. DC and AC-magnetic susceptibility results are consistent with an AFM order at TN = 52 K. The specific heat data show a lambda anomaly associated to the magnetic transition with a peak at 52 K (cord = 99 J/molTbK). The analysis of thermodiffractograms of neutron diffraction patterns indicates that, below the ordering temperature, the magnetic reflections can be indexed with a commensurate lattice related to the crystallographic cell (Pmna) by a propagation vector k = (1/2, 1/2, 1/2). The results are compared with those reported for other magnetic rare earth alloys of R2Al-type (with R = Nd, Gd and Dy).

  14. DFT study of Al doped armchair SWCNTs

    NASA Astrophysics Data System (ADS)

    Dhiman, Shobhna; Rani, Anita; Kumar, Ranjan; Dharamvir, Keya

    2016-05-01

    Electronic properties of endohedrally doped armchair single-walled carbon nanotubes (SWCNTs) with a chain of six Al atoms have been studied using ab-initio density functional theory. We investigate the binding energy/atom, ionization potential, electron Affinity and Homo-Lumo gap of doped armchair SWNTs from (4,4) to (6,6) with two ends open. BE/dopant atom and ionization potential is maximum for (6, 6) doped armchair carbon nanotube; suggest that it is more stable than (4, 4) and (5, 5) doped tubes. HOMO - LUMO gap of Al doped arm chair carbon nanotubes decreases linearly with the increase in diameter of the tube. This shows that confinement induce a strong effect on electronic properties of doped tubes. These combined systems can be used for future nano electronics. The ab-initio calculations were performed with SIESTA code using generalized gradient approximation (GGA).

  15. Polarized Cold Neutron Capture in ^27Al

    NASA Astrophysics Data System (ADS)

    Balascuta, Septimiu

    2013-04-01

    The NPDGamma Experiment at the Spallation Neutron Source at ORNL is measuring the parity-odd correlation between the neutron spin and the direction of the emitted photon in the capture of cold neutrons on a 16-liter liquid parahydrogen target. The goal is to determine the strength of the weak nucleon-nucleon interaction. One of the main background contributions comes from the gamma rays produced by neutrons captured in the Al walls of the target vessel. To quantify this effect a commissioning experiment measured the parity-odd and parity-even asymmetries in the angular distribution of the gamma rays from the capture of polarized cold neutrons in a solid Al target. A status of the analysis of this experiment will be presented.

  16. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Viswanathan, S.; Santella, M.L.

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, and wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.

  17. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Santella, M.L.; Alexander, D.J.

    1995-05-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for (1)high-strength castable composition for turbochargers, furnace furniture, and hot-die applications; (2) castability (fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) hot fabricability of cast ingots. All of the issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes work completed to address some of these issues during the fourth quarter of FY 1994.

  18. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS. PMID:26441696

  19. Response to de la Iglesia et al.

    PubMed

    Yetish, Gandhi; Kaplan, Hillard; Gurven, Michael; Wood, Brian; Pontzer, Herman; Manger, Paul R; Wilson, Charles; McGregor, Ronald; Siegel, Jerome M

    2016-04-01

    We wish to respond to the commentary of de la Iglesia et al. [1]. Studies comparing sleep in different communities have different goals. One frequent goal has been to determine how sleep is affected by manipulating specific 'modern' conditions. Many studies have investigated the effect of artificial light and electronic entertainment. Such studies have clearly shown that light, particularly blue light, delays sleep onset [2]. Studying the effect of artificial light on sleep was not a goal of our study. PMID:27046810

  20. Redistribution of Ti and Al in deuterium charged TiAl

    NASA Technical Reports Server (NTRS)

    Legzdina, D.; Robertson, I. M.; Birnbaum, H. K.

    1992-01-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration.

  1. Softening Kinetics in High Al and High Al-Nb-Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Pereda, B.; Aretxabaleta, Z.; López, B.

    2015-03-01

    Double-hit torsion tests were performed in order to study the effect of high Al levels (up to 2 wt.%) and Nb microalloying (up to 0.07 wt.%) on the static softening kinetics of 0.2%C-2%Mn steels. The addition of 1%Al leads to a delay in the softening kinetics due to solute-drag effect, equivalent to that exerted by 0.027%Nb. For the 2%Al steels, at temperatures below 1000 °C, γ → α phase transformation occurs after deformation, resulting in a larger retardation of the softening kinetics. At temperatures higher than 1000 °C, Nb in solid solution also contributes to the retardation of the static softening kinetics, and at lower temperatures NbC strain-induced precipitation leads to incomplete softening for the 1%Al steel, and to a complex interaction between softening, phase transformation, and NbC strain-induced precipitation for the 2%Al-Nb steels. The effect of Al on the static softening kinetics was quantified and introduced in a model developed in previous works for the prediction of the austenite microstructural evolution. In order to validate the results of the model, multipass torsion tests were carried out at conditions representative of hot strip and plate rolling mills. Model predictions show reasonable agreement with the results obtained at different deformation conditions.

  2. A comparative wear study on Al-Li and Al-Li/SiC composite

    SciTech Connect

    Okumus, S. Cem Karslioglu, Ramazan Akbulut, Hatem

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  3. A comparative wear study on Al-Li and Al-Li/SiC composite

    NASA Astrophysics Data System (ADS)

    Okumus, S. Cem; Karslioglu, Ramazan; Akbulut, Hatem

    2013-12-01

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al2O3 ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms-1 and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  4. FeAl and NbAl3 Intermetallic-HVOF Coatings: Structure and Properties

    NASA Astrophysics Data System (ADS)

    Guilemany, J. M.; Cinca, N.; Dosta, S.; Cano, I. G.

    2009-12-01

    Transition metal aluminides in their coating form are currently being explored in terms of resistance to oxidation and mechanical behavior. This interest in transition metal aluminides is mainly due to the fact that their high Al content makes them attractive for high-temperature applications. This is also a reason to study their resistance to wear; they may be suitable for use in applications that produce a lot of wear in aggressive environments, thus replacing established coating materials. In this study, the microstructure, microhardness, and wear and oxidation performance of FeAl and NbAl3 coatings produced by high-velocity oxy-fuel spraying are evaluated with two main aims: (i) to compare these two coating systems—a commonly studied aluminide (FeAl) and, NbAl3, an aluminide whose deposition by thermal spraying has not been attempted to date—and (ii) to analyze the relationship between their microstructure, composition and properties, and so clarify their wear and oxidation mechanisms. In the present study, the higher hardness of niobium aluminide coatings did not correlate with a higher wear resistance and, finally, although pesting phenomena (disintegration in oxidizing environments) were already known of in bulk niobium aluminides, here their behavior in the coating form is examined. It was shown that such accelerated oxidation was inevitable with respect to the better resistance of FeAl, but further improvements are foreseen by addition of alloying elements in that alloy.

  5. Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

    PubMed Central

    Abedini, Alam; Saion, Elias; Larki, Farhad; Zakaria, Azmi; Noroozi, Monir; Soltani, Nayereh

    2012-01-01

    Colloidal Cu@CuAlO2-Al2O3 bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a 60Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO2-Al2O3 nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO2-Al2O3 nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation. PMID:23109893

  6. Anomalous phonon properties in the silicide superconductors CaAlSi and SrAlSi

    NASA Astrophysics Data System (ADS)

    Kuroiwa, S.; Hasegawa, T.; Kondo, T.; Ogita, N.; Udagawa, M.; Akimitsu, J.

    2008-11-01

    Lattice-dynamical properties of CaAlSi and SrAlSi with a similar layer structure to MgB2 have been first investigated by both Raman-scattering and ab initio calculations. All Raman-active phonons with E' symmetry have been clearly observed for both compounds. Their line shapes are asymmetric but their linewidths are ˜10cm-1 , which is very narrower than that of MgB2 . In addition to the Raman-active modes, several extra peaks have been observed below 160cm-1 . These low-energy extra modes can be assigned to the out-of-plane vibrations of Al perpendicular to Al-Si basal plane. Since these peak intensities are strongly affected by the incident energy (resonance Raman process), the electronic state is important for them. Moreover, in both crystals of CaAlSi and SrAlSi, we point out the energy difference for the different propagation directions along the c axis and the c plane, in spite of the very close wave vector to the Brillouin-zone center. This energy difference cannot be explained by a usual Raman-scattering scenario at this stage.

  7. Redistribution of Ti and Al in deuterium charged TiAl

    SciTech Connect

    Legzdina, D.; Robertson, I.M.; Birnbaum, H.K. )

    1992-06-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration. 10 refs.

  8. Diet and dietetics in al-Andalus.

    PubMed

    Salas-Salvadó, Jordi; Huetos-Solano, Maria D; García-Lorda, Pilar; Bulló, Mònica

    2006-08-01

    Al-Andalus society (711-1492) based its idea of health on the wisdom of Classical Greece, the Hippocratic-Galenic theories, as well as the Persian and Hindu cultures. The twelfth century in al-Andalus is considered to be the most prolific period for works of a scientific and technical nature. At the time, the main treatises on dietetics were written and this science reached its widest expression with such leading figures as Ibn Wāfīd, Avenzoar, Averroes and Maimonides, whose works revealed the first scientific knowledge on the nutritional processes of the human body. Diet was regarded as being essential for health and the prevention of disease. Dietary guidelines were written for different age groups, different body types and different seasons of the year. The amount of food to be ingested, the number of meals recommended and the order in which the food should be consumed were all issues that were discussed. A variety of foods were thought to have medicinal properties, some of which are known today. The diet in al-Andalus was varied and very probably made a substantial contribution to the origin of the present-day Mediterranean diet, rich in olive oil, wholemeal cereals, fruit and vegetables, fish, lamb, poultry, nuts and spices. We also find that many of the terms in current use in diet and agriculture are a living testimony to the Arabic influence, as are many of the dishes of our varied Mediterranean gastronomy. PMID:16923240

  9. Energetic ion bombarded Fe/Al multilayers

    SciTech Connect

    Al-Busaidy, M.S.; Crapper, M.D.

    2006-05-15

    The utility of ion-assisted deposition is investigated to explore the possibility of counteracting the deficiency of back-reflected current of Ar neutrals in the case of lighter elements such as Al. A range of energetically ion bombarded Fe/Al multilayers sputtered with applied surface bias of 0, -200, or -400 V were deposited onto Si(111) substrates in an argon atmosphere of 4 mTorr using a computer controlled dc magnetron sputtering system. Grazing incidence reflectivity and rocking curve scans by synchrotron x rays of wavelength of 1.38 A were used to investigate the structures of the interfaces produced. Substantial evidence has been gathered to suggest the gradual suppression of interfacial mixing and reduction in interfacial roughness with increases of applied bias. The densification of the Al microstructure was noticeable and may be a consequence of resputtering attributable to the induced ion bombardment. The average interfacial roughnesses were calculated for the 0, -200, and -400 V samples to be 7{+-}0.5, 6{+-}0.5, and 5{+-}0.5 A respectfully demonstrating a 30% improvement in interface quality. Data from rocking curve scans point to improved long-range correlated roughness in energetically deposited samples. The computational code based on the recursive algorithm developed by Parratt [Phys. Rev. 95, 359 (1954)] was successful in the simulation of the specular reflectivity curves.

  10. Lower motor neuron dysfunction in ALS.

    PubMed

    de Carvalho, Mamede; Swash, Michael

    2016-07-01

    In the motor system there is a complex interplay between cortical structures and spinal cord lower motor neurons (LMN). In this system both inhibitory and excitatory neurons have relevant roles. LMN loss is a marker of motor neuron disease/amyotrophic lateral sclerosis (MND/ALS). Conventional needle electromyography (EMG) does not allow LMN loss to be quantified. Measurement of compound muscle action potential (CMAP) amplitude or area, and the neurophysiological index, provide a surrogate estimate of the number of functional motor units. Increased motor neuronal excitability is a neurophysiological marker of ALS in the context of a suspected clinical and electrophysiological diagnosis. In the LMN system, fasciculation potentials (FPs) are the earliest changes observed in affected muscles, a feature of LMN hyperexcitability. Reinnervation is best investigated by needle EMG although other methods can be explored. Moreover needle EMG give information about the temporal profile of the reinnervation process, important ancillary data. Quantitative motor unit potential analysis is a valuable method of evaluating reinnervation. The importance of FPs has been recognized in the Awaji criteria for the electrodiagnosis of ALS, criteria that are a sensitive adjunct to the revised El Escorial criteria. Finally, functionality of LMN's, and perhaps excitability studies in motor nerves, aids understanding of the disease process, allowing measurement of potential treatment effects in clinical trials. Other investigational techniques, such as electrical impedance myography, muscle and nerve ultrasound, and spinal cord imaging methods may prove useful in future. PMID:27117334

  11. Complete fusion of 15N+27Al

    NASA Astrophysics Data System (ADS)

    Prosser, F. W., Jr.; Racca, R. A.; Daneshvar, K.; Geesaman, D. F.; Henning, W.; Kovar, D. G.; Rehm, K. E.; Tabor, S. L.

    1980-05-01

    The total fusion cross section for the system 15N + 27Al has been measured over an energy range 27 MeV<=Elab<=70 MeV by detection of the fusion-evaporation residues. In addition elastic scattering was measured at six energies and fitted by optical model calculations. The fusion cross section for the system saturates at 1150+/-50 mb. The data can be well described by the model of Glas and Mosel, using a reasonable set of parameters. The model of Horn and Ferguson also describes the data well if an appropriate charge radius is used. Comparison is made between these results and the fusion cross sections for 16O + 26Mg and 18O + 24Mg, which lead to the same compound nucleus. The results for 15N + 27Al are quite similar to those for 18O + 24Mg, and the differences between the fusion cross sections for these two systems and those for 16O + 26Mg may be evidence for an entrance channel effect. NUCLEAR REACTIONS 15N+27Al, Elab=27-70 MeV; measured σfusion(E) measured dσdΩ elastic scattering; data fitted with Glas and Mosel model, Horn and Ferguson model.

  12. Moléculas orgánicas obtenidas en simulaciones experimentales del medio interestelar.

    NASA Astrophysics Data System (ADS)

    Muñoz-Caro, Guillermo Manuel

    Las nubes moleculares son regiones de formación de estrellas, con temperaturas cinéticas entre 10-50 K y densidades de 103-106 átomos cm-3. Su materia está formada por gas y polvo interestelar. Estas partículas de polvo están cubiertas por una fina capa de hielo, de unos 0.01 μm, que contiene H2O y a menudo CO, CO2, CH3OH y NH3. El hielo es presumiblemente irradiado por fotones ultravioleta y rayos cósmicos en las zonas poco profundas de las nubes moleculares y las regiones circunestelares. En un sistema de vacío, P ˜ 10-7 mbar, simulamos la deposición de hielo a partir de 10 K y la irradiación ultravioleta por medio de una lámpara de descarga de hidrógeno activada con microondas. La evolución del hielo se observa por medio de un espectrómetro infrarrojo. De este modo es posible determinar la composición del hielo observado en el medio interestelar y predecir la presencia de moléculas aún no detectadas en el espacio, que han sido producto del procesamiento del hielo en nuestros experimentos. También es posible calentar el sistema hasta temperatura ambiente para sublimar el hielo depositado. Cuando el hielo ha sido previamente irradiado, se observa un residuo compuesto por moléculas orgánicas complejas, algunas prebióticas, como varios ácidos carboxílicos, aminas, amidas, ésteres y en menor proporción moléculas heterocíclicas y aminoácidos. Algunas de estas moléculas podrían detectarse en estado gaseoso por medio de observaciones milimétricas y de radio. También podrían estar presentes en el polvo cometario, cuyo análisis químico está planeado por las misiones Stardust y Rosetta. Mientras tanto, nuestro grupo está llevando a cabo el análisis de partículas de polvo interplanetario (IDPs), algunas de las cuales pueden ser de origen cometario. Al igual que ocurre con los productos obtenidos por irradiación del hielo en nuestros experimentos, algunas IDPs son ricas en material orgánico que contiene oxígeno.

  13. Solidification Behavior of gamma'-Ni3Al Containing Alloys in the Ni-Al-O System

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2007-01-01

    The chemical activities of Al and Ni in gamma(prime)-Ni3Al-containing systems were measured using the multi-cell Knudsen effusion-cell mass spectrometry technique (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K. From these measurements a better understanding of the equilibrium solidification behaviour of gamma(prime)-Ni3Al-containing alloys in the Ni-Al-O system was established. Specifically, these measurements revealed that (1) gamma(prime)-Ni3Al forms via the peritectiod reaction, gamma + Beta (+ A12O3) = gamma (prime) (+ Al2O3), at 1633 +/- 1 K, (2) the {gamma + Beta + Al2O3} phase field is stable over the temperature range 1633 through 1640 K, and (3) equilibrium solidification occurs by the eutectic reaction, L (+ Al2O3) = gamma + Beta (+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%Al (at an unknown oxygen content). When projected onto the Ni-Al binary, this behaviour is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(prime)-Ni3Al phase field.

  14. Errores fotométricos debido al uso del filtro anular de mediana en imágenes CCD

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.; Cañada, M.; Noel, N.

    El filtro anular de mediana tiene la importante propiedad de tener una escala claramente definida, lo que permite remover de una imagen CCD todos los objetos con tamaños menores a esta escala, independientemente de su morfología particular, y reemplazarlos por el correspondiente ``background" local. Este filtro es de gran utilidad para remover gradientes de fondo, ``fringing" y halos de objetos extendidos mediante el simple procedimiento de restar a la imagen original una imagen filtrada, repitiendo el proceso las veces que sea necesario. En este trabajo se presentan resultados sobre los errores que introduce este filtro en la fotometría de objetos con diferente relación S/N y su aplicación a imágenes con gradientes de fondo y ``fringing".

  15. Prevalencia y Consecuencias del Abuso Sexual al Menor en Espana (Prevalence and Consequences of Child Sexual Abuse in Spain).

    ERIC Educational Resources Information Center

    Lopez, Felix; And Others

    1995-01-01

    The prevalence and effects of child sexual abuse in Spain were studied, using interview and survey responses from 1,821 individuals. Results indicated a high prevalence of sexual abuse prior to age 17 (15 percent of males and 22 percent of females) and a number of short-term and long-term effects, including a tendency toward mental health…

  16. Creep and Toughness of Cryomilled NiAl Containing Cr

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Aikin, Beverly; Salem, Jon

    2000-01-01

    NiAl-AlN + Cr composites were produced by blending cryomilled NiAl powder with approx. 10 vol % Cr flakes. In comparison to the as-consolidated matrices, hot isostatically pressed Cr-modified materials did not demonstrate any significant improvement in toughness. Hot extruded NiAl-AlN+10.5Cr, however, possessed a toughness twice that determine for the base NiAl-AlN alloy. Measurement of the 1200 to 1400 K plastic flow properties revealed that the strength of the composites was completely controlled by the properties of the NiAl-AlN matrices. This behavior could be successfully modeled by the Rule-of-Mixtures, where load is shed from the weak Cr to the strong matrix.

  17. The oxidation of Ni-rich Ni-Al intermetallics

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Smialek, J. L.; Barrett, C. A.

    1989-01-01

    The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al203 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.

  18. The oxidation of Ni-rich Ni-Al intermetallics

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph; Smialek, James L.; Barrett, Charles A.

    1988-01-01

    The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al2O3 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.

  19. The Nature of Interfaces in Al-1050/Al-1050 and Al-1050/Mg-AZ31 Couples Joined by Magnetic Pulse Welding (MPW)

    NASA Astrophysics Data System (ADS)

    Stern, A.; Aizenshtein, M.; Moshe, G.; Cohen, S. R.; Frage, N.

    2013-07-01

    The microstructure and the phase composition of the interfaces of Al-1050/Al-1050 and Al-1050/Mg-AZ31 magnetic pulse welding (MPW) joints were characterized by SEM and TEM analyses. The mechanical properties were tested by nanoindentation. Properties of the Al-1050/Al-1050 interface joint were established. The interface is almost free from Al3Fe precipitates, which are present in the base metal. The hardness value is higher than that of the base metal; however, values of the Young's modulus of the interface and base metal are similar. It was suggested that the interface evolution in the Al-1050/Al-1050 system includes local melting and rapid solidification of the base materials. A wavy shaped heterogeneous interface was detected in the Al-1050/Mg-AZ31 joints. Some areas are free from visible intermetallic phases (IMPs), while others contain pockets of relatively coarse intermetallic precipitates. The presence of a relatively large fraction of globular porosity at the interface indicates that local melting takes place in the course of MPW. TEM characterization of regions free of IMPs at the interface reveals regions consisting of fcc supersaturated Al-Mg solid solution, apparently formed as a result of local mechanical alloying during MPW. In other regions, the composition and structure correspond to the Mg17Al12 phase, which was probably formed by local melting and rapid solidification.

  20. Short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N grown on AlN substrates

    SciTech Connect

    Nikishin, S.A.; Borisov, B.A.; Chandolu, A.; Kuryatkov, V.V.; Temkin, H.; Holtz, M.; Mokhov, E.N.; Makarov, Yu.; Helava, H.

    2004-11-08

    High-quality short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N have been grown by gas-source molecular-beam epitaxy with ammonia on Al face of AlN (0001) substrates. A significant reduction was achieved in the dislocation density, down to 3x10{sup 8} cm{sup -2}. Complete removal of residual Al{sub 2}O{sub 3} surface oxide is needed in order to obtain low dislocation density in homoepitaxy on AlN. We show that the presence of Al{sub 2}O{sub 3} islands with the surface coverage as low as 0.2% results in increased dislocation density.

  1. Chemical ordering and large tunnel magnetoresistance in Co2FeAl/MgAl2O4/Co2FeAl(001) junctions

    NASA Astrophysics Data System (ADS)

    Scheike, Thomas; Sukegawa, Hiroaki; Inomata, Koichiro; Ohkubo, Tadakatsu; Hono, Kazuhiro; Mitani, Seiji

    2016-05-01

    Epitaxial magnetic tunnel junctions (MTJs) with a Co2FeAl/CoFe (0.5 nm)/MgAl2O4/Co2FeAl(001) structure were fabricated by magnetron sputtering. High-temperature in situ annealing led to a high degree of B2-order in the Co2FeAl layers and cation order of the MgAl2O4 barrier. Large tunnel magnetoresistance (TMR) of up to 342% was obtained at room temperature (616% at 4 K), in contrast to the TMR ratio ( ≲ 160%) suppressed by the band-folding effect in Fe/cation-ordered MgAl2O4/Fe MTJs. The present study reveals that the high degree of B2-order and the resulting high spin polarization in the Co2FeAl electrodes enable us to bypass the band-folding problem in spinel barriers.

  2. A novel TiAl3/Al2O3 composite coating on γ-TiAl alloy and evaluating the oxidation performance

    NASA Astrophysics Data System (ADS)

    Wang, Jiqiang; Kong, Lingyan; Li, Tiefan; Xiong, Tianying

    2016-01-01

    A novel TiAl3/Al2O3 composite coating was prepared on γ-TiAl alloy. The process included two steps: (1) TiAl3/Al2O3 composite powders were prepared by high energy ball milling of pure Al and nano-TiO2 powders, followed by a heat-treatment; (2) the as-prepared composite powders were deposited on γ-TiAl substrate by cold spray. The cyclic oxidation was conducted at 900 °C to test the performance of the composite coating. The results showed that the composite coating had good crack resistance and effectively decreased the oxidation rate of the substrate.

  3. 77 FR 73732 - In the Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka... fi Bilad al-Rafidayn, aka The Organization of al-Jihad's Base of Operations in Iraq, aka al-Qaida of Jihad in Iraq, aka al-Qaida in Iraq, aka al-Qaida in Mesopotamia, aka al-Qaida in the Land of the...

  4. Elevated temperature wear of Al6061 and Al6061-20%Al{sub 2}O{sub 3}

    SciTech Connect

    Singh, J.; Alpas, A.T.

    1995-04-01

    Both current and potential applications of particulate reinforced aluminum alloys involve components which are required to operate under sliding contact conditions at elevated temperatures. Examples include brake rotors, piston and cylinder liners in automotive engines where operating temperatures can reach 0.5--0.8 of the melting temperature of the matrix alloy. For this reason, study of the high temperature wear resistance of aluminum alloys reinforced by Al{sub 2}O{sub 3} or SiC particles is important. These studies are also of interest for the problem of die wear during hot extrusion of aluminum matrix composites and to rationalize the process of frictional welding involved in joining of the composites. Although the room temperature tribological and mechanical behaviors of aluminum matrix composites have received considerable attention, their high temperature properties have only recently started being considered. It has been shown that Al-Si-Mg (A356) alloys with or without SiC particles show a transition from mild to severe wear when a critical temperature (at about 0.4 T{sub m}, where T{sub m} is the melting temperature of aluminum) is reached as a result of frictional heating under dry sliding conditions. In this work, high temperature wear of A16061 and A16061-20%Al{sub 2}O{sub 3} was studied at temperatures between 25--500 C. The microstructural changes that occurred during wear have been delineated in order to understand the wear mechanisms that operate at high temperatures.

  5. Al-Ca and Al-Fe metal-metal composite strength, conductivity, and microstructure relationships

    SciTech Connect

    Kim, Hyong June

    2011-01-01

    Deformation processed metal-metal composites (DMMC’s) are composites formed by mechanical working (i.e., rolling, swaging, or wire drawing) of two-phase, ductile metal mixtures. Since both the matrix and reinforcing phase are ductile metals, the composites can be heavily deformed to reduce the thickness and spacing of the two phases. Recent studies have shown that heavily drawn DMMCs can achieve anomalously high strength and outstanding combinations of strength and conductivity. In this study, Al-Fe wire composite with 0.07, 0.1, and 0.2 volume fractions of Fe filaments and Al-Ca wire composite with 0.03, 0.06, and 0.09 volume fractions of Ca filaments were produced in situ, and their mechanical properties were measured as a function of deformation true strain. The Al-Fe composites displayed limited deformation of the Fe phase even at high true strains, resulting in little strengthening effect in those composites. Al-9vol%Ca wire was deformed to a deformation true strain of 13.76. The resulting Ca second-phase filaments were deformed to thicknesses on the order of one micrometer. The ultimate tensile strength increased exponentially with increasing deformation true strain, reaching a value of 197 MPa at a true strain of 13.76. This value is 2.5 times higher than the value predicted by the rule of mixtures. A quantitative relationship between UTS and deformation true strain was determined. X-ray diffraction data on transformation of Al + Ca microstructures to Al + various Al-Ca intermetallic compounds were obtained at the Advanced Photon Source at Argonne National Laboratory. Electrical conductivity was measured over a range of true strains and post-deformation heat treatment schedules.

  6. Interfacial microstructure and growth mechanism of Al4C3 in Grf/Al composites fabricated by liquid pressure method.

    PubMed

    Xu, Wang; Chenchong, Wang; Zhichao, Zhang; Ping, Liang; Yanhua, Shi; Guofu, Zhang

    2014-10-01

    In this study, Grf/Al composite was fabricated by liquid pressure method. The diffusion layer and the nucleation and growth of Al4C3 were observed at the interface of Grf/Al composites by TEM and HRTEM. The growth mechanism of Al4C3 was analyzed in detail by crystallography theory. It was found that Al4C3 had no phase relations with the carbon fiber. (0001) layer of Al4C3 was parallel with main growth direction. Both the diffusion layer at the interface and crystal structure of Al4C3 affected the shape of Al4C3. At a certain position, Al4C3 could connect two fibers when the fibers were close to each other. PMID:25041826

  7. Influence of Reaction with XeF2 on Surface Adhesion of Al and Al2O3 Surfaces

    SciTech Connect

    Zhang, Tianfu; Park, Jeong Y.; Huang, Wenyu; Somorjai, Gabor A.

    2008-07-28

    The change of surface adhesion after fluorination of Al and Al{sub 2}O{sub 3} surfaces using XeF{sub 2} was investigated with atomic force microscopy. The chemical interaction between XeF{sub 2} and Al and Al{sub 2}O{sub 3} surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al{sub 2}O{sub 3} surfaces were obtained by etching top silicon layers of Si/Al and Si/Al{sub 2}O{sub 3} with XeF{sub 2}. The surface adhesion and chemical composition were measured as a function of time after the exposure to air or annealing (at 200 C under vauum). The correlation between the adhesion force increase and presence of AlF{sub 3} on the surface was revealed.

  8. Fabrication of Al/Al3Ti Functionally Graded Materials by Reaction Centrifugal Mixed-Powder Method

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Miura-Fujiwara, Eri; Watanabe, Yoshimi

    2011-01-01

    Formation of compositional gradient in Al/Al3Ti Functionally graded materials (FGMs) fabricated by the centrifugal method (CM) depends mainly on the centrifugal force and the processing temperature. In this study, a novel centrifugal method, reaction centrifugal mixed-powder method (RCMPM), was proposed to fabricate Al/Al3Ti FGMs under fixed centrifugal force (G=80). The effects of RCMPM processing temperature on the formation of Al3Ti intermetallics, its morphology and its distribution in the fabricated Al/Al3Ti FGMs have been investigated. Fine granular Al3Ti were observed at relatively lower processing temperature while the known coarse platelet-like particles of Al3Ti could be achieved at higher casting temperatures. Moreover, Ti3Al intermetallics compound and unreacted Ti phases are also observed along with Al3Ti particles. In addition, distribution of Al3Ti intermetallics size and their volume fraction showed a significant change when the Al/Al3Ti FGMs processed at different temperatures relative to the liquidus temperature of the master alloy.

  9. Transplacental passage of 26Al from pregnant rats to fetuses and 26Al transfer through maternal milk to suckling rats

    NASA Astrophysics Data System (ADS)

    Yumoto, S.; Nagai, H.; Matsuzaki, H.; Kobayashi, T.; Tada, W.; Ohki, Y.; Kakimi, S.; Kobayashi, K.

    2000-10-01

    Aluminium (Al) is toxic to the growth of fetuses and sucklings. However, the incorporation of Al into fetuses and sucklings in the periods of gestation and lactation has not been well clarified because Al lacks a suitable isotope for a tracer experiment. In this study, we used 26Al (a radioisotope of Al with half-life of 716,000 yr) as a tracer, and measured 26Al incorporation into fetuses and sucklings by accelerator mass spectrometry (AMS). To investigate Al incorporation into fetuses through transplacental passage, 26Al ( 26AlCl 3) was subcutaneously injected into pregnant rats on day 15 of gestation. 26Al was also subcutaneoulsy injected into lactating rats from day 1 to day 20 postpartum. By day 20 of gestation, 0.2% of the 26Al injected into a pregnant rat had been transferred to the fetuses, and 26Al was detected in the brain and liver of the fetuses. On day 9 postpartum, high levels of 26Al were demonstrated in the brain, liver, kidneys and blood of suckling rats. It is concluded that 26Al subcutaneously injected into pregnant rats and/or lactating rats is incorporated into their offspring through transplacental passage and/or maternal milk.

  10. Huave de San Mateo del Mar, Oaxaca (Huave of San Mateo del Mar, Oaxaca).

    ERIC Educational Resources Information Center

    Mexico Coll. (Mexico City)

    This document is one of 17 volumes on indigenous Mexican languages and is the result of a project undertaken by the Archivo de Lenguas Indigenas de Mexico. This volume contains information on Huave, an indigenous language of Mexico spoken in San Mateo del Mar, in the state of Oaxaca. The objective of collecting such a representative sampling of…

  11. Hot Corrosion Performance of AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa Coatings Deposited by Atmospheric Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Tao, Chong; Wang, Lei; Cheng, Nailiang; Hu, Hengfa; Liu, Yang; Song, Xiu

    2016-04-01

    AlO-CrO/NiCoCrAlYTa and AlO/NiCoCrAlYTa coatings were deposited on 316L stainless steel substrate using atmospheric plasma spraying, respectively, in order to improve the oxidation and corrosion resistance. The hot corrosion performance of the coatings at 700 and 900 °C were studied, and the detailed microstructures and phase composition of the coatings were analyzed using x-ray diffraction, scanning electron microscope with energy dispersive spectrometer, and transmission electron microscope. The results show that both coatings are structurally featured by slatted layers, consisting of amorphous phase, Cr2O3, Ni3Al, and Al2O3. The hot corrosion resistance of AlO-CrO/NiCoCrAlYTa coating is better than that of AlO/NiCoCrAlYTa coating. This improvement is attributed to lower porosity and more compact Cr2O3 in AlO-CrO/NiCoCrAlYTa coating which performs better than Al2O3 in blocking further inward progress of corrosion and oxidization.

  12. First-principles studies of Al-Ni intermetallic compounds

    SciTech Connect

    Shi Dongmin; Wen Bin; Melnik, Roderick; Yao Shan; Li Tingju

    2009-10-15

    The structural properties, heats of formation, elastic properties, and electronic structures of Al-Ni intermetallic compounds are analyzed here in detail by using density functional theory. Higher calculated absolute values of heats of formation indicate a very strong chemical interaction between Al and Ni for all Al-Ni intermetallic compounds. According to the computational single crystal elastic constants, all the Al-Ni intermetallic compounds considered here are mechanically stable. The polycrystalline elastic modulus and Poisson's ratio have been deduced by using Voigt, Reuss, and Hill (VRH) approximations, and the calculated ratio of shear modulus to bulk modulus indicated that AlNi, Al{sub 3}Ni, AlNi{sub 3} and Al{sub 3}Ni{sub 5} compounds are ductile materials, but Al{sub 4}Ni{sub 3} and Al{sub 3}Ni{sub 2} are brittle materials. With increasing Ni concentration, the bulk modulus of Al-Ni intermetallic compounds increases in a linear manner. The electronic energy band structures confirm that all Al-Ni intermetallic compounds are conductors. - Graphical abstract: Calculated bulk modulus compared to experimental and other theoretical values for the Al-Ni intermetallic compounds.

  13. Theory and X-ray Absorption Spectroscopy for Aluminum Coordination Complexes – Al K-Edge Studies of Charge and Bonding in (BDI)Al, (BDI)AlR2, and (BDI)AlX2 Complexes.

    PubMed

    Altman, Alison B; Pemmaraju, C D; Camp, Clément; Arnold, John; Minasian, Stefan G; Prendergast, David; Shuh, David K; Tyliszczak, Tolek

    2015-08-19

    Polarized aluminum K-edge X-ray absorption near edge structure (XANES) spectroscopy and first-principles calculations were used to probe electronic structure in a series of (BDI)Al, (BDI)AlX2, and (BDI)AlR2 coordination compounds (X = F, Cl, I; R = H, Me; BDI = 2,6-diisopropylphenyl-β-diketiminate). Spectral interpretations were guided by examination of the calculated transition energies and polarization-dependent oscillator strengths, which agreed well with the XANES spectroscopy measurements. Pre-edge features were assigned to transitions associated with the Al 3p orbitals involved in metal-ligand bonding. Qualitative trends in Al 1s core energy and valence orbital occupation were established through a systematic comparison of excited states derived from Al 3p orbitals with similar symmetries in a molecular orbital framework. These trends suggested that the higher transition energies observed for (BDI)AlX2 systems with more electronegative X(1-) ligands could be ascribed to a decrease in electron density around the aluminum atom, which causes an increase in the attractive potential of the Al nucleus and concomitant increase in the binding energy of the Al 1s core orbitals. For (BDI)Al and (BDI)AlH2 the experimental Al K-edge XANES spectra and spectra calculated using the eXcited electron and Core-Hole (XCH) approach had nearly identical energies for transitions to final state orbitals of similar composition and symmetry. These results implied that the charge distributions about the aluminum atoms in (BDI)Al and (BDI)AlH2 are similar relative to the (BDI)AlX2 and (BDI)AlMe2 compounds, despite having different formal oxidation states of +1 and +3, respectively. However, (BDI)Al was unique in that it exhibited a low-energy feature that was attributed to transitions into a low-lying p-orbital of b1 symmetry that is localized on Al and orthogonal to the (BDI)Al plane. The presence of this low-energy unoccupied molecular orbital on electron-rich (BDI)Al distinguishes

  14. Revisiting the Al/Al2O3 Interface: Coherent Interfaces and Misfit Accommodation

    PubMed Central

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; Lazić, Ivan; Valone, Steven M.; Liu, Xiang-Yang

    2014-01-01

    We study the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. Our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al2O3 composite heterostructures. PMID:24670940

  15. Deep SiO2 etching with Al and AlN masks for MEMS devices

    NASA Astrophysics Data System (ADS)

    Bliznetsov, Vladimir; Mao Lin, Hua; Zhang, Yue Jia; Johnson, David

    2015-08-01

    Silicon oxide-based materials such as quartz and silica are widely used in microelectromechanical systems (MEMS). One way to enhance the capability of their deep plasma etching is to increase selectivity by the use of hard masks. Although this approach was studied previously, information on the use of hard masks for the etching of silicon-oxide based materials on 200 mm substrates is scarce. We present the results of etching process development for amorphous silicon oxide using Al and AlN masks with a view of the application of the results for the etching of silica and quartz. Three gas chemistries (C4F8/O2, CF4 and SF6) and their mixtures were compared in an industrial reactive ion etch (RIE) chamber with two plasma sources. It was established that pure SF6 is the best etchant and AlN is a better mask than Al for providing higher selectivity and a sidewall angle close to vertical. A range of etching parameters for micromasking-free etching was established and etched structures of up to a 4 : 1 aspect ratio were created in 21 μm-thick oxide using the process with an etch rate of 0.32-0.36 μm min-1 and a selectivity to AlN mask of (38-49) : 1.

  16. Tribological Properties of Ti(Al,O)/Al2O3 Composite Coating by Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Salman, Asma; Gabbitas, Brian; Cao, Peng; Zhang, Deliang

    The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity air fuel (HVAF) thermally sprayed wear resistant Ti(Al,O)/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting and dummy blocks aluminium extrusion. A feedstock of Ti(Al,O)/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity air-fuel (HVAF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The wear resistance of the coating was investigated by a tribometer using a spherical ended alumina pin as a counter body under dry and lubricating conditions. The results showed that composite coating has lower wear rate at high temperature than at room temperature without using lubricant. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

  17. Microstructure evolution and properties of Al/Al-Mg-Si alloy clad wire during heat treatment

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Guan, Ren-guo; Zhang, Yang; Su, Ning; Ji, Lian-ze; Li, Yuan-dong; Chen, Ti-jun

    2016-06-01

    In this paper, heat treatment was carried out on Al/Al-Mg-Si alloy clad wire, and microstructure evolution and properties of Al/Al-Mg-Si alloy clad wire during heat treatment were investigated. During solution, contents of Mg and Si in inner matrix increased due to dissolution of primary Mg2Si, and they also increased in outer matrix because Mg and Si diffused across the interface. Tensile strength of the clad wire increased firstly and then decreased, and elongation continuously increased, while conductivity continuously decreased with the increase in solution time. In aging process, Mg2Si precipitated in both inner core and outer layer, and the content and average diameter of the precipitate increased with the increase in aging time. The content of precipitate was higher, and the average diameter was bigger in inner core. Tensile strength of the clad wire increased firstly and then decreased with the increase in aging time, and the elongation continuously decreased, while the conductivity continuously increased. The peak tensile strength of 202 MPa occurred at 8 h, when the corresponding elongation was 20 % and the conductivity reached 56.07 %IACS. Even tensile strength of the prepared clad wire approximately equaled to that of Al-0.5Mg-0.35Si alloy 203 MPa, the conductivity was obviously improved from 54.2 to 56.07 %IACS.

  18. Revisiting the Al/Al2O3 Interface: Coherent Interfaces and Misfit Accommodation

    DOE PAGESBeta

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; Lazić, Ivan; Valone, Steven M.; Liu, Xiang-Yang

    2014-03-27

    We report the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface.more » Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. In conclusion, our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al2O3 composite heterostructures.« less

  19. Distribución del continuo ultravioleta e infrarrojo en estrellas Be

    NASA Astrophysics Data System (ADS)

    Cruzado, A.; Ringuelet, A.; di Rocco, H.

    Estamos interesados en interpretar los excesos de flujo infrarrojo y/o ultravioleta observados en estrellas Be con respecto al de estrellas B normales, así como su posible correlación. Una envoltura rodeando la estrella distingue una estrella Be de una B normal; para explicar las observaciones es necesario entonces tener en cuenta todos los posibles procesos físicos que en ella tienen lugar. Adoptando un modelo atmosférico específico, hemos estudiado el proceso de recombinación dielectrónica de metales como MgII y FeII, teniendo en cuenta la posible influencia de la opacidad del medio en el flujo emitido.

  20. Transformation to Ni5Al3 in a 63.0 at. pct Ni-Al alloy

    NASA Technical Reports Server (NTRS)

    Khadkikar, P. S.; Locci, I. E.; Vedula, K.; Michal, G. M.

    1993-01-01

    Microstructures of 63 at. pct P/M Ni-Al alloys with a composition close to the stoichiometry of the Ni5Al3 phase were investigated using homogenized and quenched specimens aged at low temperatures for various times. Results of analyses of XRD data and electron microscopy observations were used for quantitative phase analysis, performed to calculate the (NiAl + Ni5Al3)/Ni5Al3 phase boundary locations. The measured lattice parameters of Ni5Al3 phase formed at 823, 873, and 923 K indicated an increase in tetragonality of the phase with increasing nickel content.