176 research outputs found

    Application of CARS to scramjet combustion

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    A coherent anti-Stokes Raman spectroscopic (CARS) instrument has been developed for measuring simultaneously temperature and N2 - O2 species concentration in hostile flame environments. A folded BOXCARS arrangement was employed to obtain high spatial resolution. Polarization discrimination against the nonresonant background decreased the lower limits of O2 detectivity. The instrument has been primarily employed for validation of computational fluid-dynamics computer-model codes. Comparisons have been made to both the CHARNAL and TEACH codes on a hydrogen diffusion flame with good results

    The Three Tsunamis

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    We often talk about how different our world is from our parent's world. We then extrapolate this thinking to our children and try to imagine the world they will face. This is hard enough. However, change is changing! The rate at which change is occurring is accelerating. These new ideas, technologies and ecologies appear to be coming at us like tsunamis. Our approach to responding to these oncoming tsunamis will frame the future our children will live in. There are many of these tsunamis; I am just going to focus on three really big ones heading our way

    Rayleigh Scattering Measurements in NASA Langley's Hypersonic Facilities

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    The charts used in a presentation on Rayleigh scattering measurements in a hypersonic wind tunnel are presented. These charts depict advanced two dimensional laser diagnostics and the ArF excimer laser setup used in the measurements

    The 1992 NASA Langley Measurement Technology Conference: Measurement Technology for Aerospace Applications in High-Temperature Environments

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    An intensive 2-day conference to discuss the current status of measurement technology in the areas of temperature/heat flux, stress/strain, pressure, and flowfield diagnostics for high temperature aerospace applications was held at Langley Research Center, Hampton, Virginia, on April 22 and 23, 1993. Complete texts of the papers presented at the Conference are included in these proceedings

    Yield differences between Sultana clones related to virus status and genetic factors

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    Differences in yield between Sultana clones were found to be partly transmissible by grafting and partly not. The most important graft transmissible factor was leafroll, mild symptoms being associat.ed with yield reduction in 3 out of 6 seasons with a mean overall of 14 %, and severe symptoms in all 6 seasons with a mean of 35 %. The lower yields were related to fewer bunches per vine and in some seasons for severe leafroll with fewer berries per bunch. Shoot growth was delayed in spring with severe leafroll and less total annual growth was produced. There was a smaller reduction in total annual growth with mild leafrqll. Severe leafroll did not alter the colour of the fruit, either fresh, or dried with or without dipping. Sugar concentration was only slightly reduced when either mild or severe leafroll was present. Fanleaf virus in addition to severe leafroll was associated with a further reduction in yield and growth in some seasons.Yield differences not transmissible by grafting ranged up to about 50 %. The lowest yielding source vine which did not transmit reduced yield by grafting also showed puckered leaf and more oblate berry characters which were not transmitted by grafting. This was the only source vine showing any obvious morphological differences.Ertragsdifferenzen zwischen Sultana-Klonen in Beziehung zum Grad der Viruserkrankung und zu genetischen Faktoren Ertragsdifferenzen zwischen Sultana-Klonen konnten teilweise durch Pfropfung übertragen werden, teilweise nicht. Der wichtigste pfropfübertragbare Faktor war die Rollkrankheit. Beim Vorliegen leichter Krankheitssymptome war der Traubenertrag in 3 von 6 Jahren um durchschnittlich 14 % verringert; bei stark rollkranken Reben war in allen 6 Jahren ein mittlerer Ertragsrückgang von 35 % zu verzeichnen. Die niedrigeren Erträge waren durch weniger Trauben je Rebe, in einigen Jahren bei starker Erkrankung auch durch weniger Beeren je Traube bedingt. Das Triebwachstum war bei schwerer Rollkrankheit im Frühjahr verzögert, und es wurde weniger Holz erzeugt; bei leichter Erkrankung war die Holzproduktion weniger rückläufig. Starke Erkrankung veränderte die Beerenfärbung nicht, weder bei frischen noch bei getauchten oder nichtgetauchten getrockneten Beeren. Die Zuckerkonzentration war sowohl bei milder wie bei starker Rollkrankheit nur geringfügig vermindert. Schwere Rollkrankheit mit zusätzlichem Fanleafvirus war in einigen Jahren mit einer weiteren Verringerung von Traubenertrag und Holzproduktion verbunden.Die durch Pfropfung nicht übertragbaren Ertragsunterschiede erreichten annähernd 50 %. Die am schwächsten tragende Ausgangsrebe dieser Kategorie zeigte runzliges Laub und stärker abgeplattete Beeren; diese Merkmale waren nicht pfropfübertragbar. Nur diese eine Ausgangsrebe wies überhaupt deutliche morphologische Abweichungen auf

    CARS Temperature Measurements in a Hypersonic Propulsion Test Facility

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    Nonintrusive diagnostic measurements were performed in the supersonic reacting flow of the Hypersonic Propulsion Test Cell 2 at NASA-Langley. A Coherent Anti-stokes Raman Spectroscopy (CARS) system was assembled specifically for the test cell environment. System design considerations were: (1) test cell noise and vibration; (2) contamination from flow field or atmospheric borne dust; (3) unwanted laser or electrically induced combustion (inside or outside the duct); (4) efficient signal collection; (5) signal splitting to span the wide dynamic range present throughout the flow field; (6) movement of the sampling volume in the flow; and (7) modification of the scramjet model duct to permit optical access to the reacting flow with the CARS system. The flow in the duct was a nominal Mach 2 flow with static pressure near one atmosphere. A single perpendicular injector introduced hydrogen into the flow behind a rearward facing step. CARS data was obtained in three planes downstream of the injection region. At least 20 CARS data points were collected at each of the regularly spaced sampling locations in each data plane. Contour plots of scramjet combustor static temperature in a reacting flow region are presented

    Union learning representatives in the UK: activity, impact and organization

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    The debate over the significance of union learning representatives (ULRs) in the UK has become increasingly polarized. Some commentators see little prospect of ULRs contributing to advancing either workplace learning or union organization due to the constraints of neo-liberal state policy. An opposing view emphasizes union agency in developing a collective approach to learning and extended joint regulation through a process of critical engagement. This article presents analysis of data from the 2009 National Survey of ULRs, which finds a positive relationship between ULR activity and its impact in enhancing training outcomes, increasing union membership and the joint regulation of workplace learning. This supports arguments that agency of ULRs is not inevitably suppressed by the structural limitations of union learning

    Daily surveillance of falls is feasible and reveals a high incidence of falls among older adults

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    OBJECTIVE: To ensure accurate data capture for a fall study through a system of daily contact with participants. METHODS: Fifty‐eight adults older than 60 years of age and living independently in the community in Canberra, Australia, were recruited for a prospective fall study. We adopted a system of daily contact with study participants for at least 12 months, either by email or by text, asking whether they had suffered a fall in the previous 24 h. At the final testing session, we asked participants whether they had experienced a fall during the previous twelve months. RESULTS: We found no evidence that the daily reporting regime led to excess participant attrition. Only three participants withdrew over the course of the study, and the burden of responding was not cited as a factor in any of these cases. Of the 55 participants who completed the full twelve‐month study period, 38 (69%) experienced at least one fall. We also identified inconsistencies between recall of falls occurring during the last twelve months of the study and the contemporaneously recorded data. CONCLUSIONS: Previous studies have found that increasing the reporting demands on fall study participants will lead to higher attrition. This study demonstrates that it is possible to maintain participant engagement and minimise attrition with appropriate design of reporting procedures. We confirm existing evidence regarding the unreliability of retrospective recall of falls. The study highlights the importance of comprehensive and accurate data capture and points to the possibility of under‐reporting of fall incidence

    A Future State for NASA Laboratories - Working in the 21st Century

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    The name "21 st Century Laboratory" is an emerging concept of how NASA (and the world) will conduct research in the very near future. Our approach is to carefully plan for significant technological changes in products, organization, and society. The NASA mission can be the beneficiary of these changes, provided the Agency prepares for the role of 21st Century laboratories in research and technology development and its deployment in this new age. It has been clear for some time now that the technology revolutions, technology "mega-trends" that we are in the midst of now, all have a common element centered around advanced computational modeling of small scale physics. Whether it is nano technology, bio technology or advanced computational technology, all of these megatrends are converging on science at the very small scale where it is profoundly important to consider the quantum effects at play with physics at that scale. Whether it is the bio-technology creation of "nanites" designed to mimic our immune system or the creation of nanoscale infotechnology devices, allowing an order of magnitude increase in computational capability, all involve quantum physics that serves as the heart of these revolutionary changes

    Activity pacing: moving beyond taking breaks and slowing down

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    This brief communication responds to the paper by Jeong and Cho (Qual Life Res 26(4):903–911, 2017) that has described activity pacing in limited terms of adjusting activities through going at a slower rate and taking breaks. Activity pacing was reported as not involving goal setting, in comparison to other strategies for long-term conditions such as Acceptance and Commitment Therapy. This brief communication aims to challenge this limited perception of activity pacing in light of numerous studies that recognise pacing to be a more complex strategy. Pacing is considered to be a multifaceted coping strategy, including broad themes of not only adjusting activities, but also planning activities, having consistent activity levels, acceptance of current abilities and gradually increasing activities, and one that includes goal setting as a key facet. It is essential that pacing is both defined and measured as a multifaceted strategy in order to assess the outcomes of pacing, and for meaningful comparisons with other strategies regarding efficacy for the management of long-term conditions
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