18,779 research outputs found
Field measurement of penetrator seismic coupling in sediments and volcanic rocks
Field experiments were conducted to determine experimentally how well a seismometer installed using a penetrator would be coupled to the ground. A dry lake bed and a lava bed were chosen as test sites to represent geological environments of two widely different material properties. At each site, two half-scale penetrators were fired into the ground, a three-component geophone assembly was mounted to the aft end of each penetrator, and dummy penetrators were fired at various distances to generate seismic signals. The recorded signals were digitized, and cross-spectral analyses were performed to compare the observed signals in terms of power spectral density ratio, coherence and phase difference. The analyses indicate that seismometers deployed by penetrators will be as well coupled to the ground as are seismometers installed by conventional methods for the frequency range of interest in earthquake seismology, although some minor differences were observed at frequencies near the upper limit of the frequency band
Lunar seismic data analysis
The scientific data transmitted continuously from all ALSEP (Apollo Lunar Surface Experiment Package) stations on the Moon and recorded on instrumentation tapes at receiving stations distributed around the Earth were processed. The processing produced sets of computer-compatible digital tapes, from which various other data sets convenient for analysis were generated. The seismograms were read, various types of seismic events were classified; the detected events were cataloged
Lattice QCD thermodynamics at finite chemical potential and its comparison with Experiments
We compare higher moments of baryon numbers measured at the RHIC heavy ion
collision experiments with those by the lattice QCD calculations. We employ the
canonical approach, in which we can access the real chemical potential regions
avoiding the sign problem. In the lattice QCD simulations, we study several
fits of the number density in the pure imaginary chemical potential, and
analyze how these fits affects behaviors at the real chemical potential. In the
energy regions between =19.6 and 200 GeV, the susceptibility
calculated at is consistent with experimental data at , while the kurtosis shows similar behavior with that of the
experimental data in the small regions . The
experimental data at 11.5 shows quite different behavior. The
lattice result in the deconfinement region,, is far from
experimental data
Study of lattice QCD at finite baryon density using the canonical approach
At finite baryon density lattice QCD first-principle calculations can not be
performed due to the sign problem. In order to circumvent this problem, we use
the canonical approach, which provides reliable analytical continuation from
the imaginary chemical potential region to the real chemical potential region.
We briefly present the canonical partition function method, describe our
formulation, and show the results, obtained for two temperatures: and in lattice QCD with two flavors of improved Wilson
fermions.Comment: 8 pages, 4 figures, Contribution to XIIth Quark Confinement and the
Hadron Spectru
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