3,043 research outputs found

    The Effect of Reaction Control System Thruster Plume Impingement on Orion Service Module Solar Array Power Production

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    NASA's new Orion Crew Exploration Vehicle has geometry that orients the reaction control system (RCS) thrusters such that they can impinge upon the surface of Orion's solar array wings (SAW). Plume impingement can cause Paschen discharge, chemical contamination, thermal loading, erosion, and force loading on the SAW surface, especially when the SAWs are in a worst-case orientation (pointed 45 towards the aft end of the vehicle). Preliminary plume impingement assessment methods were needed to determine whether in-depth, timeconsuming calculations were required to assess power loss. Simple methods for assessing power loss as a result of these anomalies were developed to determine whether plume impingement induced power losses were below the assumed contamination loss budget of 2 percent. This paper details the methods that were developed and applies them to Orion's worst-case orientation

    Big Hole (41TV2161): Two Stratigraphically Isolated Middle Holocene Components in Travis County, Texas Volume I

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    During April and May 2006, an archeological team from the Cultural Resources Section of the Planning, Permitting and Licensing Practice of TRC Environmental Corporation’s (TRC) Austin office conducted geoarcheological documentation and data recovery excavations at prehistoric site 41TV2161 (CSJ: 0440-06-006). Investigations were restricted to a 70 centimeter (cm) thick target zone between ca. 220 and 290 cm below surface (bs) on the western side of site 41TV2161 – the Big Hole site in eastern Travis County, Texas. This cultural investigation was necessary under the requirements of Section 106 of the National Historic Preservation Act (NHPA), the implementing regulations of 36CRF Part 800 and the Antiquities Code of Texas (Texas Natural Resource Code, Title 9, Chapter 191 as amended) to recover a sample of the significant cultural materials prior to destruction by planned construction of State Highway 130 (SH 130). The latter by a private construction firm – Lone Star Infrastructure. This necessary data recovery was for Texas Department of Transportation (TxDOT), Environmental (ENV) Affairs Division under a Scientific Services Contract No. 577XXSA003 (Work Authorization No. 57701SA003). Over the years since the original award, multiple work authorizations between TxDOT and TRC were implemented and completed towards specific aspects of the analyses and reporting. The final analyses and report were conducted under contract 57-3XXSA004 (Work Authorization 57-311SA004). All work was under Texas Antiquities Committee Permit No. 4064 issued by the Texas Historical Commission (THC) to J. Michael Quigg. Initially, an archeological crew from Hicks & Company encountered site 41TV2161 during an intensive cultural resource inventory conducted south of Pearce Lane along the planned construction zone of SH 130 in the fall of 2005. Following the initial site discovery, archeologists expanded their investigations to the west across the SH 130 right-of-way, and completed excavation of 10 backhoe trenches, 13 shovel tests, and 11 test units at site 41TV2161. The investigations encountered at least seven buried cultural features and 1,034 artifacts, some in relatively good context. The survey and testing report to TxDOT presented their findings and recommendations (Campbell et al. 2006). The ENV Affairs Division of TxDOT and the THC reviewed the initial findings and recommendations, and determined site 41TV2161 was eligible for listing on the National Register of Historic Places and as State Antiquities Landmark as the proposed roadway development was to directly impact this important site and further excavations were required. Subsequently, TRC archeologists led by Paul Matchen (Project Archeologist) and J. Michael Quigg (Principal Investigator) initiated data recovery excavations through the mechanical-removal of between 220 and 250 cm of sediment from a 30-by-40 meter (m) block area (roughly 3,000 m3). This was conducted to allow hand-excavations to start just above the deeply buried, roughly 70 cm thick targeted zone of cultural material. Mechanical stripping by Lone Star Infrastructure staff created a large hole with an irregular bottom that varied between 220 and 260 cmbs. To locate specific areas to initiate hand-excavations within the mechanically stripped area, a geophysical survey that employed ground penetrating radar (GPR) was conducted by Tiffany Osburn then with Geo-Marine in Plano, Texas. Over a dozen electronic anomalies were detected through the GPR investigation. Following processing, data filtering, and assessment, Osburn identified and ranked the anomalies for investigation. The highest ranked anomalies (1 through 8) were thought to have the greatest potential to represent cultural features. Anomalies 1 through 6 were selected and targeted through hand-excavations of 1-by-1 m units that formed continuous excavation blocks of various sizes. Blocks were designated A, B, C, D, E, and F. The type, nature, quantity, and context of encountered cultural materials in each block led the direction and expansion of each excavation block as needed. In total, TRC archeologists hand-excavated 38.5 m3 (150 m2) from a vertically narrow target zone within this deep, multicomponent and stratified prehistoric site. Hand-excavation in the two largest Blocks, B and D (51 m2 and 62 m2 respectively), revealed two vertically separate cultural components between roughly 220 and 290 cmbs. The younger component was restricted to Block B and yielded a Bell/Andice point and point base, plus a complete Big Sandy point. These points were associated with at least eight small burned rock features, one cluster of ground stone tools, limited quantities of lithic debitage, few formal chipped and ground stone tools, and a rare vertebrate faunal assemblage. Roughly 20 to 25 cm below the Bell/Andice component in Block B and across Block D was a component identified by a single corner-notched Martindale dart point. This point was associated with a scattered burned rocks, three charcoal stained hearth features, scattered animal, bird, and fish bones, mussel shells, and less than a dozen formal chipped and ground stone tools. Both identified components contained cultural materials in good stratigraphic context with high spatial integrity. Significant, both were radiocarbon dated by multiple charcoal samples to a narrow 200-year period between 5250 and 5450 B.P. during the middle Holocene. With exception of the well-preserved faunal assemblages, perishable materials were poorly preserved in the moist silty clay loam. Charcoal lacked structure and was reduced to dark stains. Microfossils (e.g., phytoliths and starch gains) were present, although in very limited numbers and deteriorated conditions. The four much smaller Blocks (A, C, E, and F) yielded various quantities of cultural material and features, but these blocks also lacked sufficient charcoal dates and diagnostic artifacts Those artifacts and samples were left unassigned and analyzed separately from the Bell/Andice and Martindale components. The two well-defined components in Blocks B and D are the focus of this technical report. The components provide very significant data towards understanding rare and poorly understood hunter-gatherer populations during late stages of the Altithermal climate period. This final report builds upon the interim report submitted to TxDOT (Quigg et al. 2007) that briefly described the methods, excavations, preliminary findings, initial results from six feasibility studies, and proposed an initial research design for data analyses. Context and integrity of the cultural materials in the two identified components was excellent. This rare circumstance combined with detailed artifact analyses, solid documentation of their ages through multiple radiocarbon dates, and multidisciplinary approach to analyses, allowed significant insights and contributions concerning the two populations involved. Results provide a greater understanding of human behaviors during a rarely identified time in Texas Prehistory. The cultural materials and various collected samples were temporarily curated at TRC’s Austin laboratory. Following completion of analyses and acceptance of this final report, the artifacts, paper records, photographs, and electronic database were permanently curated at the Center for Archaeological Studies (CAS) at Texas State University in San Marcos

    Effect of multi-component fertilizers on seeds yield, yield components and physiological parameters of winter oilseed rape (Brassica napus L.)

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    ArticleSubject of the discussed studies was an analysis of the impact of mineral multicomponent fertilizers, from Polish and foreign producers, on the yield and yield components of winter oilseed rape (Brassica napus var. oleifera). Two field experiments were carried out in 2015–2017 in Lipnik. The experimental crop was winter oilseed rape, hybrid cultivar DK EXPLICIT. Two factors were studied in the experiment A: 4 multi-component mineral fertilizers - two Belarusian (1 i 2), one Russian and one Polish (Polifoska 6) and 4 doses of fertilization (250, 500 and 750 kg ha-1 ). In the experiment (B) were compared two factors: 3 multi-component mineral fertilizers - Belarusian, Russian and Polish production - Polifoska 8 and 4 doses of fertilization (200, 400 and 600 kg ha-1 ). The fertilizers applied in the experiments, manufactured in Belarus, Russia and Poland, did not show variations in the amount of yield of winter rape. The number of winter rapeseed plants on the area unit (in autumn and spring) was independent of the type of fertilizers. In the experiment B, higher number of rapeseed siliques was obtained after application of Polifoska 8, than other fertilizers. Rapeseed grown on soil with the fertilizers manufactured in Belarus showed a lower value of greenness index (SPAD) and leaf area index (LAI). As a result of the application of multi-component fertilizers, manufactured in Belarus, Russia and Poland, the recorded differences in the winter rapeseed yield, yield components and physiological parameters did not exceed 10%

    Characterizing contributions of glacier melt and groundwater during the dry season in a poorly gauged catchment of the Cordillera Blanca (Peru)

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    The retreat of glaciers in the tropics will have a significant impact on water resources. In order to overcome limitations with discontinuous to nonexistent hydrologic measurements in remote mountain watersheds, a hydrochemical and isotopic mass balance model is used to identify and characterize dry season water origins at the glacier fed Querococha basin located in southern Cordillera Blanca, Peru. Dry season water samples, collected intermittently between 1998 and 2007, were analyzed for major ions and the stable isotopes of water (δ^18 O and δ^2 H). The hydrochemical and isotopic data are analysed using conservative characteristics of selected tracers and relative contributions are calculated based on pre-identified contributing sources at mixing points sampled across the basin. The results show that during the dry-season, groundwater is the largest contributor to basin outflow and that the flux of groundwater is temporally variable. The groundwater contribution significantly correlates (P-value=0.004 to 0.044) to the antecedent precipitation regime at 3 and 18–36 months. Assuming this indicates a maximum of 4 years of precipitation accumulation in groundwater reserves, the Querococha watershed outflows are potentially vulnerable to multi-year droughts and climate related changes in the precipitation regime. The results show that the use of hydrochemical and isotopic data can contribute to hydrologic studies in remote, data poor regions, and that groundwater contribution to tropical proglacial hydrologic systems is a critical component of dry season discharge

    Cultural Resource Survey of the U.S. Highway 67 Water Improvement Project, City of Presidio, Presidio County, Texas

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    The City of Presidio is proposing to upgrade their water distribution system, provide services to the Colonia of Las Pampas, north of Presidio, and improve the overall water system reliability to accommodate these additional demands. Following a review of the proposed undertaking, the Texas Historic Commission (THC) recommended that a cultural resource survey be performed (THC letter dated October 21, 2015). To meet its responsibilities under existing State and Federal statutes, the City contracted TRC Environmental Corporation (TRC) of Austin to conduct the necessary cultural resource survey. Subsequently, TRC archeologists submitted a Texas Antiquities Permit Application to the THC, and Antiquities Permit #7722 was issued to archeologist Benjamin G. Bury, who served as Principal Investigator. The Area of Potential Effect (APE) consists of approximately 8.18 acres and includes the existing Texas Department of Transportation (TxDOT) ROW along U.S. 67 and two 0.02 acre parcels adjacent to the ROW that are currently privately owned, but will be acquired by TxDOT as new ROW easements prior to construction. The project will be funded by the Border Environment Cooperation Commission (BECC). Given the involvement of the U. S. Environmental Protection Agency (USEPA) with the BECC, the USEPA is the lead federal agency for this effort. Fieldwork was conducted on July 26th and July 27th, 2016. The field effort consisted of a systematic pedestrian survey at 15 m (50 ft.) intervals across the APE. Cultural resources documented during the survey included one historic site (41PS1220) and three isolated core reduction flakes that were widely separated and not associated with any other cultural materials. Site 41PS1220 consists of mid-to late-20th century trash left from informal dumping along U.S. 67. The dumping ground has been graded smooth in the last 30 years. Consequently, site materials are in a secondary context. Given these disturbances, TRC recommends that site 41PS1220 is not eligible for inclusion in the National Register of Historic Places (NRHP) or qualified for nomination as a State Antiquities Landmark (SAL). Additionally, one previously recorded site (41PS346) recorded within the ROW in 1976 was not relocated during the investigation, and has likely been significantly redeposited during previous road maintenance activities. TRC recommends that the portion of site 41PS346 within the U.S. 67 ROW is not eligible for inclusion in the NRHP or qualified for nomination as a SAL. Therefore, TRC recommends the project proceed as planned

    Communication skills training in undergraduate medicine.

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    Good communication with patients is now recognised as the cornerstone in effective medical practice. Medical students do not automatically acquire the art of good communication through clinical training. A new course to promote the development of communication skills at undergraduate level is described. The course was provided at the juncture between pre-clinical and clinical training. Course evaluation illustrated the value of the course as perceived by students themselves and highlighted the areas of greatest need for students in communication skills training
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