8,652 research outputs found

    An experimental investigation of the aerodynamics and cooling of a horizontally-opposed air-cooled aircraft engine installation

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    A flight-test based research program was performed to investigate the aerodynamics and cooling of a horizontally-opposed engine installation. Specific areas investigated were the internal aerodynamics and cooling mechanics of the installation, inlet aerodynamics, and exit aerodynamics. The applicable theory and current state of the art are discussed for each area. Flight-test and ground-test techniques for the development of the cooling installation and the solution of cooling problems are presented. The results show that much of the internal aerodynamics and cooling technology developed for radial engines are applicable to horizontally opposed engines. Correlation is established between engine manufacturer's cooling design data and flight measurements of the particular installation. Also, a flight-test method for the development of cooling requirements in terms of easily measurable parameters is presented. The impact of inlet and exit design on cooling and cooling drag is shown to be of major significance

    Variable maternal nutrition and growth hormone treatment in the second quarter of pregnancy in pigs alter semitendinosus muscle in adolescent progeny

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    Maternal nutrition and growth hormone (GH) treatment during early- to mid-pregnancy can each alter the subsequent growth and differentiation of muscle in progeny. We have investigated the effects of varying maternal nutrition and maternal treatment with porcine (p) GH during the second quarter of pregnancy in gilts on semitendinosus muscle cross-sectional area and fibre composition of progeny, and relationships between maternal and progeny measures and progeny muscularity. Fifty-three Large White×Landrace gilts, pregnant to Large White×Duroc boars, were fed either 2·2 kg (about 35 % ad libitum intake) or 3·0 kg commercial ration (13·5 MJ digestible energy, 150 g crude protein (N×6·25)/kg DM)/d and injected with 0, 4 or 8 mg pGH/d from day 25 to 50 of pregnancy, then all were fed 2·2 kg/d for the remainder of pregnancy. The higher maternal feed allowance from day 25 to 50 of pregnancy increased the densities of total and secondary fibres and the secondary:primary fibre ratio in semitendinosus muscles of their female progeny at 61 d of age postnatally. The densities of secondary and total muscle fibres in semitendinosus muscles of progeny were predicted by maternal weight before treatment and maternal plasma insulin-like growth factor-II during treatment. Maternal pGH treatment from day 25 to day 50 of pregnancy did not alter fibre densities, but increased the cross-sectional area of the semitendinosus muscle; this may be partially explained by increased maternal plasma glucose. Thus, maternal nutrition and pGH treatment during the second quarter of pregnancy in pigs independently alter muscle characteristics in progeny.Kathryn L. Gatford, Jason E. Ekert, Karina Blackmore, Miles J. De Blasio, Jodie M. Boyce, Julie A. Owens, Roger G. Campbell and Phillip C. Owen

    Punch-through jets in A+AA+A collisions at RHIC/LHC

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    High pTp_T single and dihadron production is studied within a NLO pQCD parton model with jet quenching in high energy A+AA+A collisions at the RHIC/LHC energy. A simultaneous χ2\chi^2-fit to both single and dihadron spectra can be achieved within a narrow range of energy loss parameter. Punch-through jets are found to result in the dihadron suppression factor slightly more sensitive to medium than the single hadron suppression factor at RHIC. Such jets at LHC are found to dominate high pTp_T dihadron production and the resulting dihadron spectra are more sensitive to the initial parton distribution functions than the single hadron spectra.Comment: 4 pages, 4 figures, proceedings for the 20th international conference on ultra-relativistic nucleus-nucleus collisions (QM2008), Jaipur, India, February 4-10, 200

    Scout motor performance analysis and prediction study /PAPS/

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    Scout motor performance analysis and predictio

    Nuclear corrections in neutrino-nucleus DIS and their compatibility with global NPDF analyses

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    We perform a global chi^2-analysis of nuclear parton distribution functions using data from charged current neutrino-nucleus deep-inelastic scattering (DIS), charged-lepton-nucleus DIS, and the Drell-Yan (DY) process. We show that the nuclear corrections in nu-A DIS are not compatible with the predictions derived from l^+A DIS and DY data. We quantify this result using a hypothesis-testing criterion based on the chi^2 distribution which we apply to the total chi^2 as well as to the chi^2 of the individual data sets. We find that it is not possible to accommodate the data from nu-A and l^+A DIS by an acceptable combined fit. Our result has strong implications for the extraction of both nuclear and proton parton distribution functions using combined neutrino and charged-lepton data sets.Comment: 5 page

    Neutrino Dimuon Production and the Strangeness Asymmetry of the Nucleon

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    We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and anti-strange parton distributions, s(x)s(x) and sˉ(x)\bar{s}(x). To explore the strangeness sector, we adopt a general parametrization of the non-perturbative s(x),sˉ(x)s(x), \bar{s}(x) functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral [S]01x[s(x)sˉ(x)]dx[S^{-}]\equiv \int_0^1 x [s(x)-\bar{s}(x)] dx, is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange Multiplier method to probe the quality of the global fit as a function of [S][S^-] and find 0.001<[S]<0.004-0.001 < [S^-] < 0.004. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made.Comment: 23 pages, 4 figures; expanded version for publicatio

    Nuclear PDFs from neutrino deep inelastic scattering

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    We study nuclear effects in charged current deep inelastic neutrino-iron scattering in the frame-work of a chi^2 analysis of parton distribution functions. We extract a set of iron PDFs and show that under reasonable assumptions it is possible to constrain the valence, light sea and strange quark distributions. Our iron PDFs are used to compute x_{Bj}-dependent and Q^2-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for charged lepton-iron scattering. We find that, except for very high x_{Bj}, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering.Comment: 25 pages, 10 figures; minor updates to match published versio

    Programming the brain: common outcomes and gaps in knowledge from animal studies of IUGR

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    Available online 7 June 2016Abstract not availableDamien S. Hunter, Susan J. Hazel, Karen L. Kinda, Julie A. Owens, Julia B. Pitcher, Kathryn L. Gatfor
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