2,143 research outputs found

    Turbulent flow over a wavy boundary

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    CER71-72PSB-JEC44.Includes bibliographical references (pages 53-57).May 1972.An experimental study was made of turbulent flow over a wavy surface. Sinusoidal waves of three sizes were used to explore the variations of flow with wave size. Measurements of mean and turbulent velocities were taken with a two-wire method. Local heat transfer rates and pressures on the wavy surface were also measured. An equilibrium turbulent boundary layer, which conforms to Rotta's and Clauser's self-preservation requirements, develops in the region far downstream from the first wave. In the lower portion of this layer, the mean velocity is represented by the logarithmic velocity profile when the form-drag measurements of skin friction are used to determine the shift-in-origin. The roughness function is related to the wave height since the wavy surface is shown to be a "k" type surface. The velocity defect profile in the logarithmic form extends to higher values of yu*/Ļ*Uāˆž than those for smooth wall flows. Eddy viscosity results support the assumed logarithmic velocity variation in the lower part of the boundary layer. Measurements of shear stress by either the two-wire or the heated-film method disagree with the form drag measurements of skin friction. The wavy surface is an extended surface windbreak since it reduces the overall wind speed above the surface and creates vortices between the waves. However, surface shear stresses are increased, and the erosion rate of field waves is a function of wave height.U.S. Department of Interior, Office of Water Resources Research, Contract No. 14-01-0001, U.S. Department of Defense, Office of Naval Research, Contract No. N00014-68-A-0493-0001

    Editorial Board

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    This nursery was organized in response to the need for improving adaptation and obtaining genetic information on the resistance or reaction to the different stress environments (biotic and abiotic) to which beans are subjected in production areas. Results are given for the best black- and red-seeded lines of the 1987 VIDAC, covering characteristics such as 100 seeds, days to flowering and physiological maturity, wt. of and response to diseases such as rust (Uromyces phaseoli), bacterioses (Xanthomonas phaseoli), BGMV, and web blight (Thanatephorus cucumeris). The yield potential and genetic adaptation of the best materials over different sites are also analyzed. Information on these national and regional trials should be collected in an efficient regional information and documentation center. (CIAT)Este vivero se organizo con base en la necesidad de conseguir una mejor adaptacion e informacion genetica sobre la resistencia o la reaccion a los diferentes ambientes de estres (bioticos o abioticos) a los cuales se somete el frijol en las areas de produccion. Se presentan los resultados de las mejores lineas de semilla negra y semilla roja de los VIDAC de 1987, para las caracteristicas de peso de 100 semillas, dias a floracion y a madurez fisiologica, y respuesta a enfermedades como roya (Uromyces phaseoli), bacteriosis (Xanthomonas phaseoli), BGMV y mustia hilachosa (Thanathephorus cucumeris). Tambien, se examinan el potencial de rendimiento y la adaptacion genetica de los mejores materiales en diferentes sitios. Es necesario reunir gran cantidad de informacion sobre estos ensayos nacionales y regionales en un centro de informacion y documentacion regional eficiente. (CIAT

    Evolving the Technical Infrastructure of the Planetary Data System for the 21st Century

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    The Planetary Data System (PDS) was established in 1989 as a distributed system to assure scientific oversight. Initially the PDS followed guidelines recommended by the National Academies Committee on Data Management and Computation (CODMAC, 1982) and placed emphasis on archiving validated datasets. But overtime user demands, supported by increased computing capabilities and communication methods, have placed increasing demands on the PDS. The PDS must add additional services to better enable scientific analysis within distributed environments and to ensure that those services integrate with existing systems and data. To face these challenges the Planetary Data System (PDS) must modernize its architecture and technical implementation. The PDS 2010 project addresses these challenges. As part of this project, the PDS has three fundamental project goals that include: (1) Providing more efficient client delivery of data by data providers to the PDS (2) Enabling a stable, long-term usable planetary science data archive (3) Enabling services for the data consumer to find, access and use the data they require in contemporary data formats. In order to achieve these goals, the PDS 2010 project is upgrading both the technical infrastructure and the data standards to support increased efficiency in data delivery as well as usability of the PDS. Efforts are underway to interface with missions as early as possible and to streamline the preparation and delivery of data to the PDS. Likewise, the PDS is working to define and plan for data services that will help researchers to perform analysis in cost-constrained environments. This presentation will cover the PDS 2010 project including the goals, data standards and technical implementation plans that are underway within the Planetary Data System. It will discuss the plans for moving from the current system, version PDS 3, to version PDS 4

    PDS4: Developing the Next Generation Planetary Data System

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    The Planetary Data System (PDS) is in the midst of a major upgrade to its system. This upgrade is a critical modernization of the PDS as it prepares to support the future needs of both the mission and scientific community. It entails improvements to the software system and the data standards, capitalizing on newer, data system approaches. The upgrade is important not only for the purpose of capturing results from NASA planetary science missions, but also for improving standards and interoperability among international planetary science data archives. As the demands of the missions and science community increase, PDS is positioning itself to evolve and meet those demands

    Electron Beam Ion Source Pre-Injector Diagnostics

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    Differential effects of dietary supplements on metabolomic profile of smokers versus non-smokers.

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    BackgroundCigarette smoking is well-known to associate with accelerated skin aging as well as cardiovascular disease and lung cancer, in large part due to oxidative stress. Because metabolites are downstream of genetic variation, as well as transcriptional changes and post-translational modifications of proteins, they are the most proximal reporters of disease states or reversal of disease states.MethodsIn this study, we explore the potential effects of commonly available oral supplements (containing antioxidants, vitamins and omega-3 fatty acids) on the metabolomes of smokers (n = 11) compared to non-smokers (n = 17). At baseline and after 12 weeks of supplementation, metabolomic analysis was performed on serum by liquid and gas chromatography with mass spectroscopy (LC-MS and GC-MS). Furthermore, clinical parameters of skin aging, including cutometry as assessed by three dermatologist raters blinded to subjects' age and smoking status, were measured.ResultsLong-chain fatty acids, including palmitate and oleate, decreased in smokers by 0.76-fold (P = 0.0045) and 0.72-fold (P = 0.0112), respectively. These changes were not observed in non-smokers. Furthermore, age and smoking status showed increased glow (P = 0.004) and a decrease in fine wrinkling (P = 0.038). Cutometry showed an increase in skin elasticity in smokers (P = 0.049) but not in non-smokers. Complexion analysis software (VISIA) revealed decreases in the number of ultraviolet spots (P = 0.031), and cutometry showed increased elasticity (P = 0.05) in smokers but not non-smokers.ConclusionsAdditional future work may shed light on the specific mechanisms by which long-chain fatty acids can lead to increased glow, improved elasticity measures and decreased fine wrinkling in smokers' skin. Our study provides a novel, medicine-focused application of available metabolomic technology to identify changes in sera of human subjects with oxidative stress, and suggests that oral supplementation (in particular, commonly available antioxidants, vitamins and omega-3 fatty acids) affects these individuals in a way that is unique (compared to non-smokers) on a broad level

    An apoptosis targeted stimulus with nanosecond pulsed electric fields (nsPEFs) in E4 squamous cell carcinoma

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    Stimuli directed towards activation of apoptosis mechanisms are an attractive approach to eliminate evasion of apoptosis, a ubiquitous cancer hallmark. In these in vitro studies, kinetics and electric field thresholds for several apoptosis characteristics are defined in E4 squamous carcinoma cells (SCC) exposed to ten 300Ā ns pulses with increasing electric fields. Cell death was >95% at the highest electric field and coincident with phosphatidylserine externalization, caspase and calpain activation in the presence and absence of cytochrome c release, decreases in Bid and mitochondria membrane potential (Ī”Ļˆm) without apparent changes reactive oxygen species levels or in Bcl2 and Bclxl levels. Bid cleavage was caspase-dependent (55ā€“60%) and calcium-dependent (40ā€“45%). Intracellular calcium as an intrinsic mechanism and extracellular calcium as an extrinsic mechanism were responsible for about 30 and 70% of calcium dependence for Bid cleavage, respectively. The results reveal electric field-mediated cell death induction and progression, activating pro-apoptotic-like mechanisms and affecting plasma membrane and intracellular functions, primarily through extrinsic-like pathways with smaller contributions from intrinsic-like pathways. Nanosecond second pulsed electric fields trigger heterogeneous cell death mechanisms in E4 SCC populations to delete them, with caspase-associated cell death as a predominant, but not an unaccompanied event

    Surface plasmon resonance modulation in nanopatterned Au gratings by the insulator-metal transition in vanadium dioxide films

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    Correlated experimental and simulation studies on the modulation of Surface Plasmon Polaritons (SPP) in Au/VO2 bilayers are presented. The modification of the SPP wave vector by the thermallyinduced insulator-to-metal phase transition (IMT) in VO2 was investigated by measuring the optical reflectivity of the sample. Reflectivity changes are observed for VO2 when transitioning between the insulating and metallic states, enabling modulation of the SPP in the Au layer by the thermally induced IMT in the VO2 layer. Since the IMT can also be optically induced using ultrafast laser pulses, we postulate the viability of SPP ultrafast modulation for sensing or control. (C)2015 Optical Society of Americ

    Optically Pumped Polarized 3^3He++^{++} Ion Source Development for RHIC/EIC

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    The proposed polarized 3^3He++^{++} acceleration in RHIC and the future Electron-Ion Collider will require about 2Ɨ10112\times10^{11} ions in the source pulse. A new technique had been proposed for production of high intensity polarized 3^3He++^{++} ion beams. It is based on ionization and accumulation of the 3^3He gas (polarized by metastability-exchange optical pumping and in the 5 T high magnetic field) in the existing Electron Beam Ion Source (EBIS). A novel 3^3He cryogenic purification and storage technique was developed to provide the required gas purity. An original gas refill and polarized 3^3He gas injection to the EBIS long drift tubes, (which serves as the storage cell) were developed to ensure polarization preservation. An infrared laser system for optical pumping and polarization measurements in the high 3--5 T field has been developed. The 3^3He polarization 80--85\% (and sufficiently long āˆ¼30\sim30 min relaxation time) was obtained in the \lq\lq{open}\rq\rq\ cell configuration with refilling valve tube inlet and isolation valve closed. The development of the spin-rotator and 3^3He 4^4He absolute nuclear polarimeter at 6 MeV 3^3He++^{++} beam energy is also presented.Comment: 9 pages, 11 figure
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