7,151 research outputs found
Propagating plane harmonic waves through finite length plates of variable thickness using finite element techniques
An analysis is given using finite element techniques which addresses the propagaton of a uniform incident pressure wave through a finite diameter axisymmetric tapered plate immersed in a fluid. The approach utilized in developing a finite element solution to this problem is based upon a technique for axisymmetric fluid structure interaction problems. The problem addressed is that of a 10 inch diameter axisymmetric fixed plate totally immersed in a fluid. The plate increases in thickness from approximately 0.01 inches thick at the center to 0.421 inches thick at a radius of 5 inches. Against each face of the tapered plate a cylindrical fluid volume was represented extending five wavelengths off the plate in the axial direction. The outer boundary of the fluid and plate regions were represented as a rigid encasement cylinder as was nearly the case in the physical problem. The primary objective of the analysis is to determine the form of the transmitted pressure distribution on the downstream side of the plate
Speculations on Isolated Lepton Events at HERA
Speculations on mechanisms which might be responsible for events with an
isolated high p_T lepton, a hadron jet and missing energy, as observed in the
H1 experiment at HERA, are discussed.Comment: LaTeX, 6 pages, 2 figures, presented at the XXXI Conference of
Theoretical Physics "Matter to the Deepest", Ustron, Poland, September 5-11,
200
Reconstructing the Chargino System at Linear Colliders
In most supersymmetric theories charginos, , belong
to the class of the lightest supersymmetric particles. The chargino system can
be reconstructed completely in collider experiments:
. By measuring the total
cross sections and the asymmetries with polarized beams, the chargino masses
and the gaugino-higgsino mixing angles of these states can be determined
accurately. If only the lightest charginos are
kinematically accessible in a first phase of the machine, transverse beam
polarization or the measurement of chargino polarization in the final state is
needed to determine the mixing angles. From these observables the fundamental
SUSY parameters can be derived: the SU(2) gaugino mass , the modulus and
the cosine of the CP-violating phase of the higgsino mass parameter , and
, the ratio of the vacuum expectation values of the two
neutral Higgs doublet fields. The remaining two-fold ambiguity of the phase can
be resolved by measuring the normal polarization of the charginos. Sum rules of
the cross sections can be exploited to investigate the closure of the
two-chargino system.Comment: 25 pages, 6 figure
Critical issues of double-metal layer coating on FBG for applications at high temperatures
Use of fiber Bragg gratings (FBGs) to monitor high temperature (HT) applications is of great interest to the research community. Standard commercial FBGs can operate up to 600 ∘ C. For applications beyond that value, specific processing of the FBGs must be adopted to allow the grating not to deteriorate. The most common technique used to process FBGs for HT applications is the regeneration procedure (RP), which typically extends their use up to 1000 ∘ C. RP involves a long-term annealing of the FBGs, to be done at a temperature ranging from 550 to 950 ∘ C. As at that temperature, the original coating of the FBGs would burn out, they shall stay uncoated, and their brittleness is a serious concern to deal with. Depositing a metal coating on the FBGs prior to process them for RP offers an effective solution to provide them with the necessary mechanical strengthening. In this paper, a procedure to provide the FBG with a bimetallic coating made by copper and nickel electrodeposition (ED) is proposed, discussing issues related to the coating morphology, adherence to the fiber, and effects on the grating spectral response. To define the processing parameters of the proposed procedure, production tests were performed on dummy samples which were used for destructive SEM-EDS analysis. As a critical step, the proposed procedure was shown to necessitate a heat treatment after the nickel ED, to remove the absorbed hydrogen. The spectral response of the FBG samples was monitored along the various steps of the proposed procedure and, as a final proof test for adherence stability of the bimetallic coating, along a heating/cooling cycle from room temperature to 1010 ∘ C. The results suggest that, given the emergence of Kirkendall voids at the copper-nickel interface, occurring at the highest temperatures (700-1010 ∘ C), the bimetallic layer could be employed as FBG coating up to 700 ∘ C
Leptoquark/Squark Interpretation of HERA Events: Virtual Effects in e+e- Annihilation to Hadrons
In reference to the recently observed high Q^2, large x events in
deep-inelastic positron-proton scattering at HERA, various leptoquark and
supersymmetric scenarios are discussed. We study the impact of virtual
leptoquark or R-parity breaking squark exchange as well as generic contact
interaction on the production of quark-antiquark pairs in
annihilation, in particular at LEP2.Comment: LaTeX file, 20 pages, 7 figures, uses epsfig, typos fixed, a few
general references adde
Looking for CP violation in B -> tau+tau- decays
In supersymmetry with large tan(beta) the decays B0(B0bar) -> l+l- are
dominated by the scalar and pseudoscalar Higgs penguin diagrams leading to
strong enhancement of leptonic decay rates with potentially large CP
asymmetries in the tau+tau- decay modes measurable in BELLE or BaBar
experiments. The TAUOLA tau-lepton decay library supplemented by its universal
interface can efficiently be used to search for B0(B0bar) -> tau+tau- decays,
and to investigate how the CP asymmetry is reflected in realistic experimental
observables.Comment: LaTeX, 12 pages, 3 figures, Talk given at the International
Conference "Matter to the Deepest'', Ustron, Poland, 8-14 September 200
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