996 research outputs found

    A data base of synthetic photometry in the GALEX ultraviolet bands for the stellar sources observed with the International Ultraviolet Explorer

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    The Galaxy Evolution Explorer (GALEX) has produced the largest photometric catalogue of ultraviolet (UV) sources. As such, it has defined the new standard bands for UV photometry: the near UV band (NUV) and the far UV band (FUV). However, due to brightness limits, the GALEX mission has avoided the Galactic plane which is crucial for astrophysical research and future space missions. The International Ultraviolet Explorer (IUE) satellite obtained 63,755 spectra in the low dispersion mode during its 18 years lifetime. We have derived the photometry in the GALEX bands for the stellar sources in the IUE Archive to extend the GALEX data base with observations including the Galactic plane.Good quality spectra have been selected for all IUE classes of stellar sources. The GALEX FUV and NUV magnitudes have been computed using the GALEX transmission curves, as well as the conversion equations between flux and magnitudes provided by the mission (galexgi.gsfc.nasa.gov). Consistency between GALEX and IUE synthetic photometries has been tested using White Dwarfs (WD) contained in both samples. The non-linear response performance of GALEX inferred from this data agrees with the results from GALEX calibration. The photometric data base is made available to the community through the services of the Centre de Donn\'ees Stellaires at Strasbourg (CDS). The catalogue contains FUV magnitudes for 1,631 sources, ranging from FUV=1.81 to FUV=18.65 mag. In the NUV band, the catalogue includes observations for 1,005 stars ranging from NUV = 3.08 to NUV= 17.74 mag . UV photometry for 1,493 not included in the GALEX AIS GR5 catalogue is provided; most of them are hot (O-A spectral type) stars. The sources in the catalogue are distributed over the full sky, including the Galactic plane.Comment: Submitted to Astronomy & Astrophysic

    Economic Assessment of a Highly Pathogenic Avian Influenza Outbreak in Washington and Benton Counties in Arkansas

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    Highly Pathogenic Avian Influenza (HPAI) presents a substantial economic risk to the poultry industry. Domesticated fowl contract HPAI initially through exposure, direct or indirect with migratory waterfowl and outbreaks can result in significant economic losses to growers and the poultry industry at large. A HPAI outbreak occurred in Minnesota and Iowa and spread across over 13 other states in 2014 and 2015. This caused an estimated 1.6billioninlosses(CDC,2016)andledtoshortagesofeggsandturkeystogetherwithelevatedprices(Annietal.2005).EvensmalloutbreaksofHPAIinflictsubstantialdamagesasUSDAAPHISguidelinesnecessitatea10kmradiusquarantineareaandpossiblecullfromthesiteofinfection.PreviousliteratureevaluateseconomicdamagesfromAIpredominantlyusingcasestudiesofpastoutbreaks,butaprioriestimationofpotentialeconomiclossesresultingfromHPAIoutbreaksincriticalindustryregionshasbeengivenlessattention.Weassesseconomicdamagestopoultrygrowers,companies,andthefederalgovernmentresultingfromasimulatedHPAIoutbreaksacrossspatiallyspecificpoultryhouselocationsinthehighvaluepoultrygrowingregionofWashingtonandBentoncountiesinArkansas.WithasimulationmodelbuiltusingStatisticalAnalysisSystem(SAS9.4),weassignedpoultryoperationtypes(Broilers,Breeders,Pullets,Turkeys,andLayers)tofacilitiesusingdiscretenonuniformprobabilitiesfromknowncountylevelpoultrytypedistributionsreportedbyUSDA.AsinglefacilityisrandomlyinfectedwithHPAI,andhouseswithinthequarantinezoneareidentifiedbasedonadistancematrixcalculatedinaGIS(ArcGISforDesktop10.4).Thevalueofeconomicdamagesisdeterminedusingmeanbirdvaluesbypoultrytypeonthelifecycleofthebirds.Becausethetotaldamagesandnumberofimpactedhousesdependonhousetypesandthelocationoftheinitialinfection,weranthemodelonethousandtimeswiththelocationofinfectionrandomlytoaccountforspatialvariability.Resultsshowthatonaverage,aninfectioninBentonorWashingtonCounty,impacts162poultryhouses,includingBroiler(119),Pullet(7),Breeder(17),BrownLayer(2),Turkey(16),andWhiteLayer(1)houses,thefederalgovernmentthroughindemnitypaymentsincursthegreatesteconomiclosses(1.6 billion in losses (CDC, 2016) and led to shortages of eggs and turkeys together with elevated prices (Anni et al. 2005). Even small outbreaks of HPAI inflict substantial damages as USDA-APHIS guidelines necessitate a 10-km radius quarantine area and possible cull from the site of infection. Previous literature evaluates economic damages from AI predominantly using case studies of past outbreaks, but a priori estimation of potential economic losses resulting from HPAI outbreaks in critical industry regions has been given less attention. We assess economic damages to poultry growers, companies, and the federal government resulting from a simulated HPAI outbreaks across spatially specific poultry house locations in the high-value poultry-growing region of Washington and Benton counties in Arkansas. With a simulation model built using Statistical Analysis System (SAS 9.4), we assigned poultry operation types (Broilers, Breeders, Pullets, Turkeys, and Layers) to facilities using discrete non-uniform probabilities from known county-level poultry type distributions reported by USDA. A single facility is randomly infected with HPAI, and houses within the quarantine zone are identified based on a distance matrix calculated in a GIS (ArcGIS for Desktop 10.4). The value of economic damages is determined using mean bird values by poultry type on the lifecycle of the birds. Because the total damages and number of impacted houses depend on house types and the location of the initial infection, we ran the model one thousand times with the location of infection randomly to account for spatial variability. Results show that on average, an infection in Benton or Washington County, impacts 162 poultry houses, including Broiler (119), Pullet (7), Breeder (17), Brown Layer (2), Turkey (16), and White Layer (1) houses, the federal government through indemnity payments incurs the greatest economic losses (57.4 million), while poultry companies and grower incur 17.3and17.3 and 3.1 million, respectively, in opportunity costs from quarantine time

    Grandeza. Sed de vida, hambre de amor

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    Design and development of high-performance thermoplastic vulcanizates with vibration damping properties.

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    164 p.Los componentes ligeros de vehículos eléctricos se enfrentarán a nuevos requerimientos relacionados con su generación de ruido y vibración debido a que, en ausencia de un motor de combustión interna, el ruido que se genere por su vibración se hará más evidente. Para afrontar estos nuevos desafíos los conceptos de diseño y selección de materiales tradicionales deberán reconsiderarse. En este contexto, los termoplásticos elastómeros vulcanizados (TPVs, por sus siglas en inglés) son materiales interesantes debido a su baja densidad, reciclabilidad, facilidad de procesamiento y flexibilidad de diseño. Esta Tesis se enfoca en el diseño y desarrollo de TPVs de alto rendimiento para aplicaciones de amortiguación de vibraciones estructurales. Para ello, se han desarrollado nuevas formulaciones de TPVs basadas en poliamida 6 (PA6) y caucho de acrilonitrilo butadieno hidrogenado (HNBR) y se ha investigado a fondo la relación existente entre su microestructura y sus propiedades. En primer lugar, se estudió la compatibilización reactiva de las mezclas de PA6/HNBR mediante la adición de HNBR carboxílico (XHNBR). En segundo lugar, se formularon mezclas de PA6/XHNBR vulcanizadas con peróxido que contienen óxidos metálicos y antioxidantes fenólicos como un nuevo concepto para diseñar TPVs de amortiguación de vibraciones de alto rendimiento. Finalmente, se investigó la relación entre la microestructura de los materiales desarrollados y su comportamiento cuasi-estático y dinámico mecánico no lineal. En general, los resultados obtenidos han señalado el potencial de los TPVs carboxílicos como materiales de amortiguación de vibraciones de alto rendimiento. Por un lado, el enfoque explorado, basado en la compatibilización reactiva de las mezclas de PA6/HNBR añadiendo XHNBR, reveló nuevas estrategias para desarrollar mezclas de elastómeros termoplásticos con propiedades térmicas y mecánicas superiores mediante el control de las interacciones interfaciales y la morfología. Además, los resultados obtenidos resaltaron que la generación de reticulaciones iónicas mediante la adición de óxidos metálicos, representa una estrategia muy prometedora para desarrollar TPVs de alto rendimiento con propiedades de amortiguación de vibraciones en un amplio rango de temperaturas. Además, la investigación de la microestructura y el comportamiento mecánico no lineal de los materiales permitió identificar y vincular los procesos de deformación micromecánica con sus correspondientes características microestructurales. Finalmente, se han presentado interpretaciones físicas de los mecanismos de deformación observados con el fin de construir una base de conocimiento para el modelado micromecánico de TPVs. En conclusión, esta Tesis abre nuevas posibilidades para obtener TPVs de alto rendimiento con propiedades térmicas, mecánicas y de amortiguación de vibraciones personalizadas, así como para prever su comportamiento mediante herramientas de modelado micromecánico
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