1,213 research outputs found

    Method for casting polyethylene pipe

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    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene

    Study of spacecraft direct readout meteorological systems

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    Characteristics are defined of the next generation direct readout meteorological satellite system with particular application to Tiros N. Both space and ground systems are included. The recommended space system is composed of four geosynchronous satellites and two low altitude satellites in sun-synchronous orbit. The goesynchronous satellites transmit to direct readout ground stations via a shared S-band link, relayed FOFAX satellite cloud cover pictures (visible and infrared) and weather charts (WEFAX). Basic sensor data is transmitted to regional Data Utilization Stations via the same S-band link. Basic sensor data consists of 0.5 n.m. sub-point resolution data in the 0.55 - 0.7 micron spectral region, and 4.0 n.m. resolution data in the 10.5 - 12.6 micron spectral region. The two low altitude satellites in sun-synchronous orbit provide data to direct readout ground stations via a 137 MHz link, a 400 Mhz link, and an S-band link

    Advanced protective coating for superalloys

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    Superior oxidation protection for nickel-base alloys at temperatures up to 1367 K was obtained with cobalt-base alloy coating. Coating had 25 Cr, 14 Al, and 0.5 Y weight percent composition. Coating was applied by electron beam vapor deposition to thickness of 76 to 127 microns

    Predicting Arterial Oxygen Desaturation Events Via Patient Journal and Pulse Oximetry Data in Postoperative Ambulatory Surgery Patients

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    Associations between patient and procedural factors on the nature and quality of the immediate in-home recovery from anesthesia following ambulatory orthopedic surgery are unknown. Further, there is a paucity of outcomes research quantitatively categorizing in-home patient recovery and safety following discharge from same-day orthopedic procedures. Tools are available, however, to shed light on outcomes in this population, and integration of such available measures is critical. Ambulatory orthopedic surgery is a burgeoning specialty, with growth expected over the foreseeable future. The expected increased patient caseload subsequent to implementation of the Affordable Care Act and aging Baby Boom generation suggests greater morbidity and mortality is on the horizon unless aggressive measures are taken at mitigating risk. Similarly, as the obesity epidemic expands, obesity-related comorbid conditions including obstructive sleep apnea (OSA) are likely to grow. The purpose of this research was to explore the relationship between ambulatory orthopedic patient-reported activities (quality of life metrics) and diagnostic factors (physical and perioperative care data) in the immediate postoperative period that are predictive of arterial oxygen desaturation. Data was obtained using a novel patient journal exploring sleep, pain, nausea, tobacco use, alcohol use, and appetite in conjunction with a valid and reliable portable, wrist-worn pulse oximeter. Additional assessment data was taken from the preanesthetic assessment. All participants were scored according to the STOP-Bang questionnaire, an accepted survey of OSA risk. Patients were recruited from a busy metropolitan ambulatory surgery center in Richmond, Virginia that sees approximately 500 cases monthly, and a 309-bed tertiary care hospital in West Burlington, Iowa. The target sample included 52 individual patients with data collected over the first two post-operative nights following discharge. Two patients were excluded. Negative binomial regression, log10 transformation, and least-squares regression examined the relationships the STOP-Bang questionnaire, quality of life data, and physical perioperative data had on postoperative desaturation events. Results suggested the STOP-Bang score predicted desaturation events and that age and BMI were significant individual predictors. Opiate pain medication treatment, a happy mood, and home CPAP use were associated with decreased events. This study provided a unique perspective in patient safety research, relating human behaviors and experiences with postoperative oxygen desaturation. Future research projects aligned with postoperative monitoring, pulse oximetry, patient safety, and obstructive sleep apnea are potential following the findings of this study

    Sexually transmitted infection risk exposure among black and minority ethnic youth in northwest London: findings from a study translating a sexually transmitted infection risk-reduction intervention to the UK setting.

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    OBJECTIVES: Young black women are disproportionately affected by sexually transmitted infections (STI) in the UK, but effective interventions to address this are lacking. The Young Brent Project explored the nature and context of sexual risk-taking in young people to inform the translation of an effective clinic-based STI reduction intervention (Project SAFE) from the USA to the UK. METHODS: One-to-one in-depth interviews (n = 37) and group discussions (n = 10) were conducted among men and women aged 15-27 years from different ethnic backgrounds recruited from youth and genitourinary medicine clinic settings in Brent, London. The interviews explored the context within which STI-related risks were assessed, experienced and avoided, the skills needed to recognise risk and the barriers to behaviour change. RESULTS: Concurrent sexual partnerships, mismatched perceptions and expectations, and barriers to condom use contributed to STI risk exposure and difficulties in implementing risk-reduction strategies. Women attempted to achieve monogamy, but experienced complex and fluid sexual relationships. Low risk awareness, flawed partner risk assessments, negative perceptions of condoms and lack of control hindered condom use. Whereas men made conscious decisions, women experienced persuasion, deceit and difficulty in requesting condom use, particularly with older partners. CONCLUSIONS: Knowledge of STI and condom use skills is not enough to equip young people with the means to reduce STI risk. Interventions with young women need to place greater emphasis on: entering and maintaining healthy relationships; awareness of risks attached to different forms of concurrency and how concurrency arises; skills to redress power imbalances and building self-esteem

    Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements

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    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations

    Paper Session I-A - Robust Low Cost Liquid Rocket Combustion Chamber By Advanced Vacuum Plasma Process

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    Next-generation, regeneratively cooled rocket engines require materials that can meet high temperatures while resisting the corrosive oxidation-reduction reaction of combustion known as blanching, the main cause of engine failure. A project was initiated at NASA-Marshall Space Flight Center (MSFC) to combine three existing technologies to build and demonstrate an advanced liquid rocket engine combustion chamber that would provide a 100-mission life. Technology developed in microgravity research to build cartridges for space furnaces was utilized to vacuum plasma spray (VPS) a functional gradient coating on the hot wall of the combustion liner as one continuous operation, eliminating any bondline between the coating and the liner. (See Figure 1) The coating was NiCrAlY, developed previously as durable protective coatings on space shuttle high-pressure fuel turbopump (HPFTP) turbine blades. A thermal model showed that 0.035” NiCrAlY applied to the hot wall of the combustion liner would reduce the hot wall temperature 200°F, a 20% reduction, for longer life. Cu-8Cr-4Nb alloy, which was developed by NASA-Glenn Research Center (GRC), and which possesses excellent high-temperature strength, creep resistance, and low cycle fatigue behavior combined with exceptional thermal stability, was utilized as the liner material in place of NARloy-Z. The Cu-8Cr-4Nb material exhibits better mechanical properties at 650°C (1200°F) than NARloy-Z does at 538°C (1000°F). VPS formed Cu-8Cr-4Nb combustion chamber liners with a protective NiCrAlY functional gradient coating have been hot fire tested, successfully demonstrating a durable coating for the first time. Hot fire tests along with tensile and low cycle fatigue properties of the VPS formed combustion chamber liners and witness panel specimens are discussed

    A Synthesis of Implicit and Explicit Learning: Teaching Approaches and Learning Strategies

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    This synthesis has been compiled from three textbooks and two online articles. It focuses on Teaching English as a Second or Foreign Language edited and written by Marianne Celce-Murcia, which suggests "The Communicative Theory" is most effective for TESOL. This ideology is counterbalanced by two other texts, The Book of Learning and Forgetting by Frank Smith, which encourages "The Classic View" of learning or "Social Learning", and Principles of Language Learning and Teaching by Douglas Brown, which is concerned with "The Cognitive and Constructivist" view of learning. This manuscript attempts to explain implicit and explicit learning strategies, their relationship to Celce-Murcia\u27s "Nine Twentieth-Century Approaches to Language Teaching", and objectively gauge the amount of implicit and explicit learning strategies in different learning approaches

    Lightweight, Actively Cooled Ceramic Matrix Composite Thrustcells Successfully Tested in Rocket Combustion Lab

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    In a joint effort between the NASA Glenn Research Center and the NASA Marshall Space Flight Center, regeneratively cooled ceramic matrix composite (CMC) thrustcells were developed and successfully tested in Glenn's Rocket Combustion Lab. Cooled CMC's offer the potential for substantial weight savings over more traditional metallic parts. Two CMC concepts were investigated. In the first of these concepts, an innovative processing approach utilized by Hyper-Therm, Inc., allowed woven CMC coolant containment tubes to be incorporated into the complex thruster design. In this unique design, the coolant passages had varying cross-sectional shapes but maintained a constant cross-sectional area along the length of the thruster. These thrusters were silicon carbide matrix composites reinforced with silicon carbide fibers. The second concept, which was supplied by Ceramic Composites, Inc., utilized copper cooling coils surrounding a carbon-fiber-reinforced carbon matrix composite. In this design, a protective gradient coating was applied to the inner thruster wall. Ceramic Composites, Inc.'s, method of incorporating the coating into the fiber and matrix eliminated the spallation problem often observed with thermal barrier coatings during hotfire testing. The focus of the testing effort was on screening the CMC material's capabilities as well as evaluating the performance of the thermal barrier or fiber-matrix interfacial coatings. Both concepts were hot-fire tested in gaseous O2/H2 environments. The test matrix included oxygen-to-fuel ratios ranging from 1.5 to 7 with chamber pressures to 400 psi. Steady-state internal wall temperatures in excess of 4300 F were measured in situ for successful 30-sec test runs. Photograph of actively cooled composite thrustcell fabricated by Hyper-Therm is shown. The thrustcell is a silicon-carbide-fiber-reinforced silicon carbide matrix composite with woven cooling channels. The matrix is formed via chemical vapor infiltration. Photograph of hot-fire test of an actively cooled carbon-fiber-reinforced carbon matrix composite thrustcell is also shown. This composite thrustcell, which was fabricated by CCI, Inc., was wound with copper cooling coils to contain the water coolant. The tests were run with oxygen fuel ratios up to seven with chamber pressures of 200 psia

    Improving School Counselor Efficacy Through Principal-Counselor Collaboration: A Comprehensive Literature Review

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    The school counselor and principal have vital roles within a school which have a significant impact upon the way a school functions. One area of pressing conflict within principal-counselor relationships is disagreement over the appropriate role and function of the counselor. In order to investigate perceptions of the counselor role, as well as the elements of healthy relationships between principals and counselors, the authors conducted an extensive literature review. The following themes were found within the literature and are discussed: 1) school counselor roles and responsibilities, 2) principal and school counselor collaboration, and 3) characteristics of effective school counselor/principal relationships
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