3,913 research outputs found
Integration of the Distribution and Repair in Variable Environments (DRIVE) Model into MICAP Policy
The United States Air Force has implemented the Distribution and Repair In Variable Environments (DRIVE) Model to a limited degree for a limited range of items, and policy makers seem unsure as to the proper level of DRIVE utilization. New asset release sequences and policies have been proposed without evidence to support those decisions. The purpose of this study is to explore different levels of DRIVE implementation relating to proposed asset release policies in order to provide some evidence on which policy could best support Air Force weapon systems. A second purpose of this study is to show how the DRIVE Model works in terms of asset distribution decisions. The approach used in this research involved using the Uniform Material Movement and Issue Priority System (UMMIPS) as a baseline for comparison with DRIVE implementation. A historical requisition database was used in order to determine UMMIPS results, and to determine the actual allocated quantities of each asset during the two quarter period used for the comparison. The actual allocated quantities were then reallocated using five increasing levels of DRIVE implementation, resulting in a total of six research levels overall (including UMMIPS). The research results yielded evidence that DRIVE utilization does increase aircraft availability for all locations as a whole and bases with a FAD (force activity designator) of two (versus FAD one), although FAD one locations saw only a marginal decline in availability rates. Although greater DRIVE implementation over current operations did not yield higher results, pure DRIVE utilization performed as well as current operating policy, and better than UMMIPS logic without any requisition data
Using an analytic network process model to incorporate qualitative factors into multi-criteria global modal choice decisions
This research develops and evaluates an Analytic Network Process (ANP) model to choose the correct mode of global transportation in the presence of complicating qualitative influences. The ANP model effectively combines important qualitative and quantitative factors into a global modal choice model. Although there is a great deal of research in the area of modal choice, the research often focuses singularly on cost or time factors. This research incorporates security, public opinion, and customer opinion into modal choice. One of the most difficult choices a transportation planner faces is deciding when qualitative factors outweigh the quantitative ones. A reliable tool to validate choice by including the important qualitative factors with the quantitative is quite valuable in military operations, humanitarian support, and disaster relief
Loading a vapor cell magneto-optic trap using light-induced atom desorption
Low intensity white light was used to increase the loading rate of Rb
atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption
of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb
partial pressure reached a new equilibrium value in less than 10 seconds after
switching on the broadband light source. After the source was turned off, the
partial pressure returned to its previous value in times as short as 10
seconds.Comment: 7 pages, 6 figure
Stability of Solution of the Nonlinear Schr\"odinger Equation for the Bose-Einstein Condensation
We investigate the stability of the Bose-Einstein condensate (BEC) the case
of atoms with negative scattering lengths at zero temperature using the
Ginzburg-Pitaevskii-Gross (GPG) stationary theory. We have found a new exact
equation for determining the upper bound of the critical numbers of
atoms for a metastable state to exist. Our calculated value of for
Bose-Einstein condensation of lithium atoms based on our new equation is in
agreement with those observed in a agreement with those observed in a recent
experiment.Comment: 8 pages, Late
Observation of vortex dipoles in an oblate Bose-Einstein condensate
We report experimental observations and numerical simulations of the
formation, dynamics, and lifetimes of single and multiply charged quantized
vortex dipoles in highly oblate dilute-gas Bose-Einstein condensates (BECs). We
nucleate pairs of vortices of opposite charge (vortex dipoles) by forcing
superfluid flow around a repulsive gaussian obstacle within the BEC. By
controlling the flow velocity we determine the critical velocity for the
nucleation of a single vortex dipole, with excellent agreement between
experimental and numerical results. We present measurements of vortex dipole
dynamics, finding that the vortex cores of opposite charge can exist for many
seconds and that annihilation is inhibited in our highly oblate trap geometry.
For sufficiently rapid flow velocities we find that clusters of like-charge
vortices aggregate into long-lived dipolar flow structures.Comment: 4 pages, 4 figures, 1 EPAPS fil
Origin of ferroelectricity in the multiferroic barium fluorides BaMF4
We present a first principles study of the series of multiferroic barium
fluorides with the composition BaMF4, where M is Mn, Fe, Co, or Ni. We discuss
trends in the structural, electronic, and magnetic properties, and we show that
the ferroelectricity in these systems results from the "freezing in" of a
single unstable polar phonon mode. In contrast to the case of the standard
perovskite ferroelectrics, this structural distortion is not accompanied by
charge transfer between cations and anions. Thus, the ferroelectric instability
in the multiferroic barium fluorides arises solely due to size effects and the
special geometrical constraints of the underlying crystal structure.Comment: 8 pages, 6 figures, 3 table
Keys to successful balanced scorecard implementation and use based on published implementation attempts
In recent years many companies have evolved from being centrally located and managed to decentralized, multi-national companies consisting of many separate entities to be strategically managed. In response to this and other changes, such as the need for better measurement of performance, a strategic management tool was developed called the Balanced Scorecard (BSC). This research provides a tool to guide and evaluate BSC implementation. A meta-synthesis approach was used to examine qualitative BSC data available in the literature that suggested eleven keys to successful BSC implementation and use. These keys are then used to benchmark an implementation in a government logistics organization
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