2,624 research outputs found
Correctional Change Through Neuroscience
Currently, the U.S. criminal justice system is under intense scrutiny. High- profile cases question the appropriateness of specific types of evidence, decision making in sentencing, and the treatment of convicted offenders. Clearly, these issues are not new. And, as has been historically the case, the justice system looks toward science for assistance in addressing and redressing problems with the delivery of justice
IN DIVISION I HOCKEY, DOES THE PUCK STOP JUNIOR YEAR?
The 2004-2005 National Hockey League (NHL) lockout has had a twofold effect on men’s Division I college hockey programs. First, NHL entry-level contracts are now much less expensive than they were before the lockout. As a consequence, NHL teams are now more inclined to induce Division I hockey players to forego years of remaining eligibility. Second, the age of unrestricted free agency has dropped, encouraging rookies to begin their NHL career at a younger age. The authors show that there has been not only a surge in the number of Division I college players who have signed NHL contracts in the two years after 2004-2005 lockout than in the two years before the lockout, but since the lockout disproportionately more NHL bound college players have left college in their junior year.
Effect of thruster pulse length on thruster-exhaust damage of S13G white thermal control coatings
Rocket exhaust products which strike thermal control surfaces cause changes in solar absorptance (Alpha Sub s) and thermal emittance (Epsilon) of these surfaces. A study was made of the effect of rocket pulse duration on exhaust damage to S13G white coatings. Two pulse lengths were used - 14 msec and 50 msec. An MMH/N204 bipropellant 5-lb thrust rocket was fired into a simulated space environment with a vacuum of 0.00001 torr, a liquid helium temperature enclosure, and solar radiation. The changes in solar absorptance and thermal emittance of S13G white coatings due to rocket exhaust were made in-situ for total firing times of 58 seconds with 14 msec pulses and 223.7 sec with 50 msec pulses. The solar absorptance of S13G increased 25 percent due to 223.7 sec of exposure to 50 msec pulses and the thermal emittance was unaffected. The ratio of Alpha Sub s/Epsilon therefore increased by 25 percent. The short 14 msec pulse exhaust exposure caused between 40 and 70 percent increase in solar absorptance and a decrease of between 13 and 18 percent in thermal emittance. The corresponding increase in Alpha Sub s/Epsilon ratio was between 80 and 100 percent. Ultraviolet radiation was present in the short pulse test and may have contributed to the large damage of that test
Dynamical solutions of a quantum Heisenberg spin glass model
We consider quantum-dynamical phenomena in the ,
infinite-range quantum Heisenberg spin glass. For a fermionic generalization of
the model we formulate generic dynamical self-consistency equations. Using the
Popov-Fedotov trick to eliminate contributions of the non-magnetic fermionic
states we study in particular the isotropic model variant on the spin space.
Two complementary approximation schemes are applied: one restricts the quantum
spin dynamics to a manageable number of Matsubara frequencies while the other
employs an expansion in terms of the dynamical local spin susceptibility. We
accurately determine the critical temperature of the spin glass to
paramagnet transition. We find that the dynamical correlations cause an
increase of by 2% compared to the result obtained in the spin-static
approximation. The specific heat exhibits a pronounced cusp at .
Contradictory to other reports we do not observe a maximum in the -curve
above .Comment: 8 pages, 7 figure
Energy correlations for a random matrix model of disordered bosons
Linearizing the Heisenberg equations of motion around the ground state of an
interacting quantum many-body system, one gets a time-evolution generator in
the positive cone of a real symplectic Lie algebra. The presence of disorder in
the physical system determines a probability measure with support on this cone.
The present paper analyzes a discrete family of such measures of exponential
type, and does so in an attempt to capture, by a simple random matrix model,
some generic statistical features of the characteristic frequencies of
disordered bosonic quasi-particle systems. The level correlation functions of
the said measures are shown to be those of a determinantal process, and the
kernel of the process is expressed as a sum of bi-orthogonal polynomials. While
the correlations in the bulk scaling limit are in accord with sine-kernel or
GUE universality, at the low-frequency end of the spectrum an unusual type of
scaling behavior is found.Comment: 20 pages, 3 figures, references adde
Correlation of creep rate with microstructural changes during high temperature creep
Creep tests were conducted on Haynes 188 cobalt-base alloy and alpha titanium. The tests on Haynes 188 were conducted at 1600 F and 1800 F for stresses from 3 to 20 ksi, and the as-received, mill-annealed results were compared to specimens given 5%, 10%, and 15% room temperature prestrains and then annealed one hour at 1800 F. The tests on alpha titanium were performed at 7,250 and 10,000 psi at 500 C. One creep test was done at 527 C and 10,000 psi to provide information on kinetics. Results for annealed titanium were compared to specimens given 10% and 20% room temperature prestrains followed by 100 hours recovery at 550 C. Electron microscopy was used to relate dislocation and precipitate structure to the creep behavior of the two materials. The results on Haynes 188 alloy reveal that the time to reach 0.5% creep strain at 1600 F increases with increasing prestrain for exposure times less than 1,000 hours, the increase at 15% prestrain being more than a factor of ten
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