31,059 research outputs found
Proposal for a High Energy Nuclear Database
We propose to develop a high-energy heavy-ion experimental database and make
it accessible to the scientific community through an on-line interface. This
database will be searchable and cross-indexed with relevant publications,
including published detector descriptions. Since this database will be a
community resource, it requires the high-energy nuclear physics community's
financial and manpower support. This database should eventually contain all
published data from Bevalac, AGS and SPS to RHIC and LHC energies,
proton-proton to nucleus-nucleus collisions as well as other relevant systems,
and all measured observables. Such a database would have tremendous scientific
payoff as it makes systematic studies easier and allows simpler benchmarking of
theoretical models to a broad range of old and new experiments. Furthermore,
there is a growing need for compilations of high-energy nuclear data for
applications including stockpile stewardship, technology development for
inertial confinement fusion and target and source development for upcoming
facilities such as the Next Linear Collider. To enhance the utility of this
database, we propose periodically performing evaluations of the data and
summarizing the results in topical reviews.Comment: 8 pages, 3 figures. Proceedings of the 21st Winter Workshop on
Nuclear Dynamics, Breckenridge, Colorado, February 5--12, 200
A High Energy Nuclear Database Proposal
We propose to develop a high-energy heavy-ion experimental database and make
it accessible to the scientific community through an on-line interace. This
database will be searchable and cross-indexed with relevant publications,
including published detector descriptions. Since this database will be a
community resource, it requires the high-energy nuclear physics community's
financial and manpower support. This database should eventually contain all
published data from the Bevalac, AGS and SPS to RHIC and LHC energies,
proton-proton to nucleus-nucleus collisions as well as other relevant systems
and all measured observables. Such a database would have tremendous scientific
payoff as it makes systematic studies easier and allows simpler benchmarking of
theoretical models to a broad range of old and new experiments. Furthermore,
there is a growing need for compilations of high-energy nuclear data for
applications including stockpile stewardship, technology development for
intertial confinement fusion and target and source development for upcoming
facilities such as the Next Linear Collider. To enhance the utility of this
database, we propose periodically performing evaluations of the data and
summarizing the results in topical reviews.Comment: 4 pages, poster proceedings from Quark Matter 200
Allocating and splitting free energy to maximize molecular machine flux
Biomolecular machines transduce between different forms of energy. These
machines make directed progress and increase their speed by consuming free
energy, typically in the form of nonequilibrium chemical concentrations.
Machine dynamics are often modeled by transitions between a set of discrete
metastable conformational states. In general, the free energy change associated
with each transition can increase the forward rate constant, decrease the
reverse rate constant, or both. In contrast to previous optimizations, we find
that in general flux is neither maximized by devoting all free energy changes
to increasing forward rate constants nor by solely decreasing reverse rate
constants. Instead the optimal free energy splitting depends on the detailed
dynamics. Extending our analysis to machines with vulnerable states (from which
they can break down), in the strong driving corresponding to in vivo cellular
conditions, processivity is maximized by reducing the occupation of the
vulnerable state.Comment: 22 pages, 7 figure
Resonant Acoustic Determination of Complex Elastic Moduli
A simple, inexpensive, yet accurate method for measuring the dynamic complex modulus of elasticity is described. Using a 'free-free' bar selectively excited in three independent vibrational modes, the shear modulus is obtained by measuring the frequency of the torsional resonant mode and the Young's modulus is determined from measurement of either the longitudinal or flexural mode. The damping properties are obtained by measuring the quality factor (Q) for each mode. The Q is inversely proportional to the loss tangent. The viscoelastic behavior of the sample can be obtained by tracking a particular resonant mode (and thus a particular modulus) using a phase locked loop (PLL) and by changing the temperature of the sample. The change in the damping properties is obtained by measuring the in-phase amplitude of the PLL which is proportional to the Q of the material. The real and imaginary parts or the complex modulus can be obtained continuously as a function of parameters such as temperature, pressure, or humidity. For homogeneous and isotropic samples only two independent moduli are needed in order to characterize the complete set of elastic constants, thus, values can be obtained for the dynamic Poisson's ratio, bulk modulus, Lame constants, etc
Fiber-optic push-pull sensor systems
Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems
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