321 research outputs found
A Study of the Cyclone Fractional Efficiency Curves
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Article from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 4 (2002): L. Wang, C.B. Parnell and B.W. Shaw. A Study of the Cyclone Fractional Efficiency Curves. Vol. IV. June 2002
Computationally efficient velocity profile solutions for cardiac haemodynamics
DOI: 10.1109/IEMBS.2004.1403316This paper reformulates the non-linear differential equations associated with time varying resistance in minimal cardio-vascular system models into a system of linear equations with an analytical solution. The importance of including time varying resistance is shown for a single chamber model where there is a 17.5% difference in cardiac output when compared with a constant resistance model. However, the increased complexity has significant extra computational cost. This new formulation provides a significant computational saving of 15x over the previous method. This improvement enables more physiological accuracy with minimal cost in computational time. As a result, the model can be used in clinical situations to aid diagnosis and therapy selection without compromising on physiological accuracy
Simulating transient ventricular interaction using a minimal cardiovascular system model
A minimal closed-loop cardiovascular system (CVS) model has been developed that can simulate ventricular interaction due to both direct interaction through the septum and series interaction through the circulation system. The model is used to simulate canine experiments carried out to study the transient response of the left ventricle due to changes in right ventricle pressures and volumes. The model-simulated trends in left and right ventricle pressures and volumes, septum deflection and arterial flow rates are compared with the experimental results. In spite of the limited physiological data available describing the animals, the model is shown to capture all the transient trends in the experimental data. This is the first known example of a physiological model that can capture all these trends. The model is then used to illustrate the separate effects of direct and series interactions independently. This study proves the value of this modelling method to be used in conjunction with experimental data for delineating and understanding the factors that contribute to ventricular dynamic
Liver transplantation for biliary atresia
Orthotopic liver transplantation was performed 15 months to 20 years ago in 126 recipients, all of whom were under 18 years of age. Eighty-six of these pediatric recipients were treated before 1980 with azathioprine (or eyclophosphamide) and prednisone, to which antilymphocyte globulin (ALG) usually was added. One-year patient survival was 40%. In the last 40 cases, the new drug cyclosporine has been given with low doses of steroids. The one-year patient survival increased to 65%. Both in the pre-cyclosporine era and more recently, the survival of patients with biliary atresia has been lower than in the next largest category of patients, namely, those with liver-based inborn metabolic errors. The difficulty of operation in patients with biliary atresia has been greater than in recipients with other diagnoses, partly because of previous operations such as portoenterostomy (Kasai procedure). Hepatic portoenterostomy, worthwhile as it is, has posed technical difficulties for eventual liver transplantation, particularly when complicated Roux limb techniques or venting procedures have been applied. In our total experience the longest survival after liver replacement in a child whose original diagnosis was biliary atresia is 132/3 years. © 1984 Société Internationale de Chirurgie
Improvements in Modeling 90 degree Bleed Holes for Supersonic Inlets
The modeling of porous bleed regions as boundary conditions in computational fluid dynamics (CFD) simulations of supersonic inlet flows has been improved through a scaling of sonic flow coefficient data for 90deg bleed holes. The scaling removed the Mach number as a factor in computing the sonic flow coefficient and allowed the data to be fitted with a quadratic equation, with the only factor being the ratio of the plenum static pressure to the surface static pressure. The implementation of the bleed model into the Wind-US CFD flow solver was simplified by no longer requiring the evaluation of the flow properties at the boundary-layer edge. The quadratic equation can be extrapolated to allow the modeling of small amounts of blowing, which can exist when recirculation of the bleed flow occurs within the bleed region. The improved accuracy of the bleed model was demonstrated through CFD simulations of bleed regions on a flat plate in supersonic flow with and without an impinging oblique shock. The bleed model demonstrated good agreement with experimental data and three-dimensional CFD simulations of bleed holes
Rare Charm Decays in the Standard Model and Beyond
We perform a comprehensive study of a number of rare charm decays,
incorporating the first evaluation of the QCD corrections to the short distance
contributions, as well as examining the long range effects. For processes
mediated by the transitions, we show that sensitivity to
short distance physics exists in kinematic regions away from the vector meson
resonances that dominate the total rate. In particular, we find that
and are sensitive to non-universal
soft-breaking effects in the Minimal Supersymmetric Standard Model with
R-parity conservation. We separately study the sensitivity of these modes to
R-parity violating effects and derive new bounds on R-parity violating
couplings. We also obtain predictions for these decays within extensions of the
Standard Model, including extensions of the Higgs, gauge and fermion sectors,
as well as models of dynamical electroweak symmetry breaking.Comment: 45 pages, typos fixed, discussions adde
Psychology and aggression
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68264/2/10.1177_002200275900300301.pd
Study of Charm Fragmentation into D^{*\pm} Mesons in Deep-Inelastic Scattering at HERA
The process of charm quark fragmentation is studied using meson
production in deep-inelastic scattering as measured by the H1 detector at HERA.
Two different regions of phase space are investigated defined by the presence
or absence of a jet containing the meson in the event. The
parameters of fragmentation functions are extracted for QCD models based on
leading order matrix elements and DGLAP or CCFM evolution of partons together
with string fragmentation and particle decays. Additionally, they are
determined for a next-to-leading order QCD calculation in the fixed flavour
number scheme using the independent fragmentation of charm quarks to
mesons.Comment: 33 pages, submitted to EPJ
A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site
This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be â„3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poissonâs ratio, P- and S-wave velocities, Youngâs modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda
Measurement of the cross section for isolated-photon plus jet production in pp collisions at âs=13 TeV using the ATLAS detector
The dynamics of isolated-photon production in association with a jet in protonâproton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fbâ1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photonâjet invariant mass and the scattering angle in the photonâjet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements
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