1,409 research outputs found

    Dynamics of tilt-based browsing on mobile devices

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    A tilt-controlled photo browsing method for small mobile devices is presented. The implementation uses continuous inputs from an accelerometer, and a multimodal (visual, audio and vibrotactile) display coupled with the states of this model. The model is based on a simple physical model, with its characteristics shaped to enhance usability. We show how the dynamics of the physical model can be shaped to make the handling qualities of the mobile device fit the browsing task. We implemented the proposed algorithm on Samsung MITs PDA with tri-axis accelerometer and a vibrotactile motor. The experiment used seven novice users browsing from 100 photos. We compare a tilt-based interaction method with a button-based browser and an iPod wheel. We discuss the usability performance and contrast this with subjective experience from the users. The iPod wheel has significantly poorer performance than button pushing or tilt interaction, despite its commercial popularity

    Hadronic ψ\psi production calculated in the NRQCD factorization formalism

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    The NRQCD factorization formalism of Bodwin, Braaten, and Lepage prescribes how to write quarkonium production rates as a sum of products of short-distance coefficients times non-perturbative long-distance NRQCD matrix elements. We present, in the true spirit of the factorization formalism, a detailed calculation of the inclusive cross section for hadronic ψ\psi production. We find that in addition to the well known {\it color-singlet} production mechanisms, there are equally important mechanisms in which the ccˉc\bar{c} pair that forms the ψ\psi is initially produced in a {\it color-octet} state, in either a 3S1{}^3S_1, 1S0{}^1S_0, 3P0{}^3P_0 or 3P2{}^3P_2 angular-momentum configuration. In our presentation, we emphasize the ``matching'' procedure, which %is the method that allows us to determine the short-distance coefficients appearing in the factorization formula. We also point out how one may systematically include relativistic corrections in these calculations.Comment: 25 pages, 3 postscript figures, use Revtex and epsfig.sty We fixed some typos, added some text regarding a reference, and changed some equations. The file will be available at http://phenom.physics.wisc.edu

    Charmonium production at neutrino factories

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    At existing and planned neutrino factories (high energy and high intensity neutrino beam facilities) precision studies of QCD in neutrino-nucleon interactions are a realistic opportunity. We investigate charmonium production in fixed target neutrino experiments. We find that J/ψJ/\psi production in neutrino-nucleon collision is dominated by the color octet 3S1^3S_1 NRQCD matrix element in a neutral current process, which is not accessible in photo or leptoproduction. Neutrino experiments at a future Muon Collider will acquire sufficient event rate to accurately measure color octet matrix element contributions. The currently running high energy neutrino experiments, NOMAD and NuTeV could also observe several such events.Comment: 13 pages Latex, with five embedded eps figures. Cosmetic fixups in the figures, otherwise unchange

    Evaluation of fermented whole crop wheat and barley feeding on growth performance, nutrient digestibility, faecal volatile fatty acid emission, blood constituents, and faecal microbiota in growing pigs

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    This study was conducted to determine the effects of feeding diets with fermented whole crop wheat (FWW) and fermented whole crop barley (FWB) on growth performance, nutrient digestibility, blood constituents, faecal volatile fatty acid (VFA) emission and faecal microbiota in growing pigs. A total of 200 growing pigs were randomly allotted to five treatments with eight replicates per treatment and five pigs per replicate. Dietary treatments consisted of i) CON (basal diet), ii) 0.5% FWW (CON + 0.5% fermented whole crop wheat), iii) 1.0% FWW (CON + 1.0% fermented whole crop wheat), iv) 0.5% FWB (CON + 0.5% fermented whole crop barley), and v) 1.0% FWB (CON + 1.0% fermented whole crop barley). The digestibility of total dietary fibre was significantly higher in pigs fed FWW diets. The faecal emissions of VFA of pigs fed the fermented treatments was increased significantly compared with CON. Concentrations of cortisol and triglyceride in blood of pigs fed 1.0% FWW were significantly lower than pigs fed CON diets. The pigs fed 1.0% FWB diets had a significantly decreased level of total cholesterol in blood compared with CON. In conclusion, the current results indicated that diets supplemented with FWW and FWB could increase faecal VFA emission and reduce concentration of triglyceride and cortisol, while 0.5% and 1.0% FWW had no negative effects on growth performance, and could increase digestibility of dietary fibre in growing pigs.Keywords: Dietary fibre, faecal short-chain fatty acid emissions, fermented feed, serum parameter, swin

    The stochastic gravitational wave background from turbulence and magnetic fields generated by a first-order phase transition

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    We analytically derive the spectrum of gravitational waves due to magneto-hydrodynamical turbulence generated by bubble collisions in a first-order phase transition. In contrast to previous studies, we take into account the fact that turbulence and magnetic fields act as sources of gravitational waves for many Hubble times after the phase transition is completed. This modifies the gravitational wave spectrum at large scales. We also model the initial stirring phase preceding the Kolmogorov cascade, while earlier works assume that the Kolmogorov spectrum sets in instantaneously. The continuity in time of the source is relevant for a correct determination of the peak position of the gravitational wave spectrum. We discuss how the results depend on assumptions about the unequal-time correlation of the source and motivate a realistic choice for it. Our treatment gives a similar peak frequency as previous analyses but the amplitude of the signal is reduced due to the use of a more realistic power spectrum for the magneto-hydrodynamical turbulence. For a strongly first-order electroweak phase transition, the signal is observable with the space interferometer LISA.Comment: 46 pages, 17 figures. Replaced with revised version accepted for publication in JCA

    Elastic Differential Cross Sctions for Electron Collisions with Polyatomic Molecules

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    Experimental data for electron-polyatomic molecule collisions are reviewed in connection with fusion and processing plasmas, as well as with the associated environmental issues. The electron scattering experiments for differential cross section (DCS) measurements for various processes, such as elastic scattering, have been performed across a broad range of energies (1-100 eV), mainly, at Sophia University since 1978, and some done under the collaborations with the Australian National University, Flinders University, and the Chungnam National University. As a benchmark cross section, elastic DCS are essential for the absolute scale conversion of inelastic DCS, as well as for testing computational methods. The need for cross-section data for a wide variety of molecular 2 species is also discussed, because there is an urgent need to develop an international program to provide the scientific and technological communities with authoritative cross sections for electron-molecule interactions. Note that the detailed comparison with other data available is not given here. Ruther, other available data can be found in the references we cite. This course of action was adopted to keep this report to a sensible length, so that only our numerical data is provided here

    Experimental and numerical investigation on cross flow in the PMR200 core

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    Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.The Prismatic Modular Reactor (PMR) is one of the major Very High Temperature Reactor (VHTR) concepts, which consists of hexagonal prismatic fuel blocks and reflector blocks made of nuclear grade graphite. However, the shape of graphite blocks could be easily changed by neutron damage during the reactor operation and the shape change can make the gaps between the blocks inducing bypass flow. Two types of gap shape should be considered. The vertical gap and horizontal gap are called bypass gap and cross gap, respectively. The cross gap complicates flow field in reactor core by connecting coolant channel and bypass gap and it could lead to loss of effective coolant flow in fuel blocks. In this paper, cross flow experimental facility was constructed to investigate the cross flow phenomena in the core of the VHTR and the experiment was carried out under varying flow rates and gap sizes. The results of the experiments were compared with CFD (Computational Fluid Dynamics) analysis results. In order to apply the CFD code to the cross flow phenomena, the prediction capability of the CFD code was verified. Good agreement between experimental results and CFD predictions was observed and the characteristics of the cross flow was discussed in detail.This work was supported by a Basic Atomic Energy Research Institute (BAERI) grant funded by the Korean government Ministry of Education and Science Technology (MEST) (NRF-2010-0018759)am201

    Resumming the color-octet contribution to e+ e- -> J/psi + X

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    Recent observations of the spectrum of J/psi produced in e+ e- collisions at the Upsilon(4S) resonance are in conflict with fixed-order calculations using the Non-Relativistic QCD (NRQCD) effective field theory. One problem is that leading order color-octet mechanisms predict an enhancement of the cross section for J/psi with maximal energy that is not observed in the data. However, in this region of phase space large perturbative corrections (Sudakov logarithms) as well as enhanced nonperturbative effects are important. In this paper we use the newly developed Soft-Collinear Effective Theory (SCET) to systematically include these effects. We find that these corrections significantly broaden the color-octet contribution to the J/psi spectrum. Our calculation employs a one-stage renormalization group evolution rather than the two-stage evolution used in previous SCET calculations. We give a simple argument for why the two methods yield identical results to lowest order in the SCET power counting.Comment: 27 pages, 7 figure

    NRQCD Analysis of Bottomonium Production at the Tevatron

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    Recent data from the CDF collaboration on the production of spin-triplet bottomonium states at the Tevatron p \bar p collider are analyzed within the NRQCD factorization formalism. The color-singlet matrix elements are determined from electromagnetic decays and from potential models. The color-octet matrix elements are determined by fitting the CDF data on the cross sections for Upsilon(1S), Upsilon(2S), and Upsilon(3S) at large p_T and the fractions of Upsilon(1S) coming from chi_b(1P) and chi_b(2P). We use the resulting matrix elements to predict the cross sections at the Tevatron for the spin-singlet states eta_b(nS) and h_b(nP). We argue that eta_b(1S) should be observable in Run II through the decay eta_b -> J/psi + J/psi.Comment: 20 pages, 3 figure

    A transient tribodynamic approach for the calculation of internal combustion engine piston slap noise

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    An analytical/numerical methodology is presented to calculate the radiated noise due to internal combustion engine piston impacts on the cylinder liner through a film of lubricant. Both quasi-static and transient dynamic analyses coupled with impact elasto-hydrodynamics are reported. The local impact impedance is calculated, as well as the transferred energy onto the cylinder liner. The simulations are verified against experimental results for different engine operating conditions and for noise levels calculated in the vicinity of the engine block. Continuous wavelet signal processing is performed to identify the occurrence of piston slap noise events and their spectral content, showing good conformance between the predictions and experimentally acquired signals
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