4,442 research outputs found

    Archaeological Testing of Four Sites on Camp Bowie, Brown County, Texas

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    In August of 2002, a crew from the Center for Archaeological Research (CAR) of The University of Texas at San Antonio tested four sites at Camp Bowie in Brown County Texas. Three sites, 41BR471, 41BR500, and 41BR522, were prehistoric and one site, 41BR392, had both historic and prehistoric components. This work was done under Texas Antiquities Permit No. 2926 for the Adjutant General’s Department of Texas. Testing at these sites was done based on recommendations made for 41BR500 by Mauldin and Broehm (2001) and recommendations made for 41BR392, 41BR471 and 41BR522 by Greaves (2002). Testing at 41BR392 centered on a prehistoric burned rock midden. Excavations took place in and around the midden. A few bifaces and a considerable amount of lithic debris were recovered. The size, location and density of burned rock within the midden were examined as a means of investigating the internal midden structure. Analysis of these data suggest that the midden represents an earth oven. Ethnobotanical recovery revealed the presence of geophytes. Radiocarbon dates place the feature within the Late Prehistoric period. Testing at 41BR471 involved surface collection and excavation. Excavations confirmed that the site is deflated with sub-surface deposits being shallow and very minor. What remains of this site is a moderate to dense surface scatter of unmodified debitage and a few lithic cores. Testing at 41BR500 centered on a suspected buried burned rock feature discovered during the spring 2001 survey. Excavations recovered unmodified lithic debitage, biface fragments and a scraper. Excavations in a separate area of the site where high debitage density was noted recovered a Nolan dart point dating to the Middle Archaic along with a number of bifaces and a considerable amount of unmodified lithic debitage. This additional testing uncovered a single charcoal stain, and radiocarbon dates place this feature within the Late Prehistoric period. Our analysis of the distribution of the diagnostic points, the distribution of debitage, and the radiocarbon date, suggest that much of this material is in secondary context. Test excavations at 41BR522 showed very little debitage in or around the prehistoric burned rock midden. This small midden is nearly a perfect ring of burned rock surrounding a central hearth depression. Preservation was excellent for the recovery of both charred botanical remains and for examination of the midden structure. A Montell dart point, dating to the Late Archaic was recovered. As with 41BR392, the size, location and density of burned rock within the midden was examined as a means of investigating the internal midden structure. Analysis revealed the midden to be a central hearth/earth-oven type burned rock midden. Ethnobotanical recovery revealed the presence of geophytes. Radiocarbon dates place the feature within the Late Prehistoric period. Based on the results of this testing, it is recommended that sites 41BR471 and 41BR500 are not eligible to the National Register of Historic Places and do not warrant status as State Archeological Landmarks. The sites have data that are of questionable integrity, and CAR’s testing work has effectively exhausted any remaining research potential. Sites 41BR392 and 41BR522 are recommended as eligible to the National Register of Historic Places and do warrant status as State Archeological Landmarks. Both recommended sites have data with good integrity. In addition, both sites have charcoal present, and good recovery of ethnobotanical material. Data from these sites can be used to consider a variety of research questions that are significant for understanding the prehistory of the region

    Optimal symmetric flight studies

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    Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory

    Enhanced hydrogen storage in Ni/Ce composite oxides

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    The properties of dried (but not calcined) coprecipitated nickel ceria systems have been investigated in terms of their hydrogen emission characteristics following activation in hydrogen. XRD and BET data obtained on the powders show similarities to calcined ceria but it is likely that the majority of the material produced by the coprecipitation process is largely of an amorphous nature. XPS data indicate very little nickel is present on the outermost surface of the particles. Nevertheless, the thermal analytical techniques (TGA, DSC and TPD-MS) indicate that the hydrogen has access to the catalyst present and the nickel is able to generate hydrogen species capable of interacting with the support. Both unactivated and activated materials show two hydrogen emission features, viz. low temperature and high temperature emissions (LTE and HTE, respectively) over the temperature range 50 and 500 °C. A clear effect of hydrogen interaction with the material is that the activated sample not only emits much more hydrogen than the corresponding unactivated one but also at lower temperatures. H2 dissociation occurs on the reduced catalyst surface and the spillover mechanism transfers this active hydrogen into the ceria, possibly via the formation and migration of OH− species. The amount of hydrogen obtained (0.24 wt%) is 10× higher than those observed for calcined materials and would suggest that the amorphous phase plays a critical role in this process. The affiliated emissions of CO and CO2 with that of the HTE hydrogen (and consumption of water) strongly suggests a proportion of the hydrogen emission at this point arises from the water gas shift type reaction. It has not been possible from the present data to delineate between the various hydrogen storage mechanisms reported for ceria

    Overview of the Langley subsonic research effort on SCR configuration

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    Recent advances achieved in the subsonic aerodynamics of low aspect ratio, highly swept wing designs are summarized. The most significant of these advances was the development of leading edge deflection concepts which effectively reduce leading edge flow separation. The improved flow attachment results in substantial improvements in low speed performance, significant delay of longitudinal pitch up, increased trailing edge flap effectiveness, and increased lateral control capability. Various additional theoretical and/or experimental studies are considered which, in conjunction with the leading edge deflection studies, form the basis for future subsonic research effort

    Camp Maxey IV Archaeological Testing of Six Sites, Lamar County, Texas

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    From June 14 through July 4, 2001, the Center for Archaeological Research of The University of Texas at San Antonio conducted National Register of Historic Places eligibility testing of six prehistoric archaeological sites (41LR190, 41LR194, 41LR196, 41LR200, 41LR258, and 41LR259) at Camp Maxey, Lamar County, Texas, under contract with the Texas Army National Guard. The investigations were conducted under Texas Antiquities Permit No. 2180. The Phase II testing fieldwork consisted of the excavation of twelve backhoe trenches and nineteen 1 x 1-m test units across the sites to investigate significant cultural deposits encountered during the previous survey phase. In concert with the archaeological field investigations, lithic and native ceramic analyses and magnetic sediment susceptibility studies were performed to aid in the determination of site integrity and eligibility. The synthesis of these analyses has provided adequate data to determine temporal integrity and recommendation of National Register eligibility for site 41LR190. Further cultural resources investigations in the form of Phase III data recovery excavations are thus recommended for this site prior to proposed development. Conversely, due to lack of significance criteria, sites 41LR194, 41LR196, 41LR200, 41LR258, and 41LR259 are recommended as ineligible for inclusion in the National Register and require no further cultural resources investigations

    Sensitivity of Recalibrated Continuous Glucose Monitor Data

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    Continuous glucose monitors (CGMs) are increasingly used in research settings to examine glucose metabolism in newborn babies. Accuracy of these devices depends on calibration blood glucose (BG) measurements entered into the CGM device. The potential impact of variations in timing and accuracy of reference calibration measurements on CGM device output were assessed

    Facilitators and barriers to engagement with contact tracing during infectious disease outbreaks: A rapid review of the evidence

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    BACKGROUND: Until a vaccine is developed, a test, trace and isolate strategy is the most effective method of controlling the COVID-19 outbreak. Contact tracing and case isolation are common methods for controlling infectious disease outbreaks. However, the effectiveness of any contact tracing system rests on public engagement. Numerous factors may influence an individual's willingness to engage with a contact tracing system. Understanding these factors has become urgent during the COVID-19 pandemic. OBJECTIVE: To identify facilitators and barriers to uptake of, and engagement with, contact tracing during infectious disease outbreaks. METHOD: A rapid systematic review was conducted to identify papers based on primary research, written in English, and that assessed facilitators, barriers, and other factors associated with the uptake of, and engagement with, a contact tracing system. PRINCIPAL FINDINGS: Four themes were identified as facilitators to the uptake of, and engagement with, contact tracing: collective responsibility; personal benefit; co-production of contact tracing systems; and the perception of the system as efficient, rigorous and reliable. Five themes were identified as barriers to the uptake of, and engagement with, contact tracing: privacy concerns; mistrust and/or apprehension; unmet need for more information and support; fear of stigmatization; and mode-specific challenges. CONCLUSIONS: By focusing on the factors that have been identified, contact tracing services are more likely to get people to engage with them, identify more potentially ill contacts, and reduce transmission
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