10,921 research outputs found
A possible supersymmetric solution to the discrepancy between B -> \phi K_S and B -> \eta' K_S CP asymmetries
We present a possible supersymmetric solution to the discrepancy between the
observed mixing CP asymmetries in B -> \phi K_S and B -> \eta' K_S. We show
that due to the different parity in the final states of these processes, their
supersymmetric contributions from the R-sector have an opposite sign, which
naturally explain the large deviation between S_{\phi K_S} and S_{\eta' K_S}.
We also consider the proposed mechanisms to solve the puzzle of the observed
large branching ratio of B -> \eta' K and study their impact on S_{eta' K_S}.Comment: 4 pages, 2 figure
A calculation procedure for viscous flow in turbomachines, volume 3
A method for analyzing the nonadiabatic viscous flow through turbomachine blade passages was developed. The field analysis is based upon the numerical integration of the full incompressible Navier-Stokes equations, together with the energy equation on the blade-to-blade surface. A FORTRAN IV computer program was written based on this method. The numerical code used to solve the governing equations employs a nonorthogonal boundary fitted coordinate system. The flow may be axial, radial or mixed and there may be a change in stream channel thickness in the through-flow direction. The inputs required for two FORTRAN IV programs are presented. The first program considers laminar flows and the second can handle turbulent flows. Numerical examples are included to illustrate the use of the program, and to show the results that are obtained
Smooth Hybrid Inflation and Non-Thermal Type II Leptogenesis
We consider a smooth hybrid inflation scenario based on a supersymmetric
SU(2)_L x SU(2)_R x U(1)_B-L model. The Higgs triplets involved in the model
play a key role in inflation as well as in explaining the observed baryon
asymmetry of the universe. We show that the baryon asymmetry can originate via
non-thermal triplet leptogenesis from the decay of SU(2)_L triplets, whose tiny
vacuum expectation values also provide masses for the light neutrinos.Comment: 9 pages, 2 figure
Understanding tissue morphology: model repurposing using the CoSMoS process
We present CoSMoS as a way of structuring thinking on how to reuse parts of an existing model and simulation in a new model and its implementation. CoSMoS provides a lens through which to consider, post-implementation, the assumptions made during the design and implementation of a software simulation of physical interactions in the formation of vascular structures from endothelial cells. We show how the abstract physical model and its software implementation can be adapted for a different problem: the growth of cancer cells under varying environmental perturbations. We identify the changes that must be made to adapt the model to its new context, along with the gaps in our knowledge of the domain that must be filled by wet-lab experimentation when recalibrating the model. Through parameter exploration, we identify the parameters that are critical to the dynamic physical structure of the modelled tissue, and we calibrate these parameters using a series of in vitro experiments. Drawing inspiration from the CoSMoS project structure, we maintain confidence in the repurposed model, and achieve a satisfactory degree of model reuse within our in silico experimental system
Spacetime Foam and Dark Energy
Due to quantum fluctuations, spacetime is foamy on small scales. The degree
of foaminess is found to be consistent with the holographic principle. One way
to detect spacetime foam is to look for halos in the images of distant quasars.
Applying the holographic foam model to cosmology we "predict" that the cosmic
energy density takes on the critical value; and basing only on existing
archived data on active galactic nuclei from the Hubble Space Telescope, we
also "predict" the existence of dark energy which, we argue, is composed of an
enormous number of inert "particles" of extremely long wavelength. We speculate
that these "particles" obey infinite statistics.Comment: 6 pages, LaTeX, talk given at the Fourth International Workshop on
the Dark Side of the Universe in Cairo (June 1-5, 2008), to appear in the
Proceeding
Influence of Truss Plate Connectors on the Analysis of Light Frame Structures
A method of analysis for a plane framed structure with nonrigid connections is studied. The method encompasses the concept of matrix method. Structures are modeled using two types of elements, namely, a beam element and a joint element. Each two-dimensional joint element is composed of three linear springs having no physical dimensions, representing shear, axial, and moment resistance. The mechanical properties of the joint element are obtained experimentally. Two frames and several beams are tested, and results are compared to analytical results. Good correlations are obtained.A solution of a truss with toothed metal plate connectors is presented and a general agreement with available solutions is obtained. A sensitivity study presenting the influence of joint stiffnesses is also presented. It is found that moment and axial spring properties have appreciable influence on members end forces, while the shear spring properties have little effect
Influence of laser power on tensile properties and material characteristics of laser-sintered UHMWPE
Ultra High Molecular Weight Polyethylene (UHMWPE) has excellent properties, such as high mechanical performance, low friction, high wear and chemical resistance but so far there has been limited use in additive manufacturing (AM). Laser sintering of polymers is one of the most promising AM technologies due to its ability to produce complex geometries with accurate dimensions and good mechanical properties. Consequently, this study investigates the influence of laser power on physical and mechanical properties of UHMWPE parts produced by laser sintering. In particular mechanical properties, such as Ultimate Tensile Strength (UTS), Young’s Modulus and elongation at break were evaluated alongside relative density, dilation and shrinkage. Finally, the fracture surface of the tensile test specimens was examined by electron microscopy. Results show that within a laser power range of 6–12 W there appears to be an optimum where tensile strength and relative density reach a maximum, dilation is minimised and where elongation increases with laser power. UTS up to 2.42 MPa, modulus up to 72.6 MPa and elongation at break up to 51.4% were observed. Relative density and part dimensions are also influenced by laser power
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