This article aims to identify the sociodemographic predictors associated with overnight and emergency hospital treatment among a sample of homeless adults.

This article conducts a review study to measure the effectiveness of mobile technologies to support children's literacy achievement on pre-kindergarten through 5th grade students from 2007 to 2019.

This article discusses closed-form expressions for the magnetic fields produced by rectangular- and circular-shaped finite-length solenoids and current loops. The closed-form expression for the magnetic field of a rectangular-shaped finite-length solenoid is derived using the Biot–Savart law. Closed-form expressions for the magnetic fields of solenoids and current loops can be used to avoid approximations in analytical models and may reduce computation time in computer simulations.

The performance of an idealized geothermal binary-fluid-cycle energy conversion system is shown to be a function of the temperatures of brine and working fluid leaving the heat exchanger. System power output, heat exchanger area required and initial well and heat exchanger costs are determined for counterflow, single and multi-pass parallel-counterflow exchangers. Results are presented graphically as functions of the brine and working fluid exit temperatures from the exchanger. Use of the system analysis developed is illustrated by showing quantitatively the advantage of the counterflow over the other flow arrangements considered.

Superconducting combined function magnets will be utilized for the 50GeV-750kW proton beam line for the J-PARC neutrino experiment and an R and D program has been launched at KEK. The magnet is designed to provide a combined function with a dipole field of 2.59 T and a quadrupole field of 18.7 T/m in a coil aperture of 173.4 mm. A single layer coil is proposed to reduce the fabrication cost and the coil arrangement in the 2-D cross-section results in left-right asymmetry. This paper reports the design study of the magnet.

NSTX High Harmonic Fast Wave (HHFW) current drive discharges will require density control for acceptable efficiency. We have compared boronization on hot and cold surfaces, varying helium glow discharge conditioning (HeGDC) durations, and brief morning boronization with between discharge boronization for improving density control. Access to Ohmic H-modes was enabled by boronization on hot surfaces, however, the duration of the effectiveness of hot and cold boronization was comparable. A 15 min HeGDC between discharges was needed for reproducible L-H transitions. Brief morning boronization followed by a comparable duration of applied HeGDC restored and enhanced good conditions. Additional short boronizations between discharges did not improve plasma performance (reduced recycling, reduced impurity luminosities, earlier L-H transitions, longer plasma current flattops, higher stored energies) if conditions were already good. Between discharge boronization requires increases in the duty cycle due to the need for additional HeGDC to remove co-deposited D{sub 2}.

Under the sponsorship of the U.S. DOE and DHS, we have developed a Computational Fluid Dynamics (CFD) model for simulating airflow and dispersion of chemical/biological agents released in the urban environment. Our model, FEM3MP, is based on solving the three-dimensional, time-dependent, incompressible Navier-Stokes equations on massively parallel computer platforms. The numerical algorithm uses the finite element method for accurate representation of complex building shapes and variable terrain, together with a semi-implicit projection method and modern iterative solvers for efficient time integration (Gresho and Chan, 1998). Physical processes treated in our code include turbulence modeling via the RANS (Reynolds Averaged Navier-Stokes) and LES (Large Eddy Simulation) approaches, atmospheric stability, aerosols, UV radiation decay, surface energy budget, and vegetative canopies, etc.

The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 300T{center_dot}m and 10OT{center_dot}m. Fast ramp times are needed. These can cause problems of ac loss and field distortion in the magnets. For the high energy ring, a lm model dipole magnet has been built, based on the RHIC dipole design. This magnet was tested under boiling liquid helium in a vertical dewar. The quench current showed very little dependence on ramp rate. The ac losses, measured by an electrical method, were fitted to straight line plots of loss/cycle versus ramp rate, thereby separating the eddy current and hysteresis components. These results were compared with calculated values, using parameters which had previously been measured on short samples of cable. Reasonably good agreement between theory and experiment was found, although the measured hysteresis loss is higher than expected in ramps to the highest field levels.

A numerical methodology to incorporate anisotropic elasticity into three-dimensional dislocation dynamics codes has been developed, employing theorems derived by Lothe (1967), Brown (1967), Indenbom and Orlov (1968) and Asaro and Barnett (1976). The formalism is based on the stress field solution for a straight dislocation segment of arbitrqq orientation in 3-dimensional space. The general solution is given in a complicated closed integral form. To reduce the computation complexity, look-up tables are used to avoid heavy computations for the evaluation of the angular stress factor ({Sigma}{sub ij}) and its first derivative term ({Sigma}{sub ij}). The computation methodology and error analysis are discussed in comparison with known closed form solutions for isotropic elasticity. For the case of Mo single crystals, it is shown that the difference between anisotropic and isotropic elastic stress fields can be as high as 15% close to the dislocation line, and decreases significantly far away from it. This suggests that short-range interactions should be evaluated based on anisotropic elasticity, while long-range interaction can be approximated using isotropic elasticity.

We examine the efficiency with which supernova-enriched gas may be ejected from dwarf disk galaxies, using a methodology previously employed to study the self-enrichment efficiency of dwarf spheroidal systems. Unlike previous studies that focused on highly concentrated starbursts, in the current work we consider discrete supernova events spread throughout various fractions of the disk. We model disk systems having gas masses of 10{sup 8} and 10{sup 9} M{sub {circle_dot}} with supernova rates of 30, 300, and 3000 Myr{sup -1}. The supernova events are confined to the midplane of the disk, but distributed over radii of 0, 30, and 80% of the disk radius, consistent with expectations for Type II supernovae. In agreement with earlier studies, we find that the enriched material from supernovae is largely lost when the supernovae are concentrated near the nucleus, as expected for a starburst event. In contrast, we find the loss of enriched material to be much less efficient (as low as 21%) when the supernovae occur over even a relatively small fraction of the disk. The difference is due to the ability of the system to relax following supernova events that occur over more extended regions. Larger physical separations also reduce the likelihood of …

During the epoch of large galaxy formation, thermal instability leads to the formation of a population of cool fragments which are embedded within a background of tenuous hot gas. The hot gas attains a quasi hydrostatic equilibrium. Although the cool clouds are pressure confined by the hot gas, they fall into the galactic potential, subject to drag from the hot gas. The release of gravitational energy due to the infall of the cool clouds is first converted into their kinetic energy which is subsequently dissipated as heat. The cool clouds therefore represent a potentially significant energy source for the background hot gas, depending upon the ratio of thermal energy deposited within the clouds versus the hot gas. In this paper, we show that most of dissipated energy is deposited in to the tenuous hot halo gas, which provides a source of internal energy to replenish its loss in the hot gas through Bremsstrahlung cooling and conduction into the cool clouds. Through this process, the multi-phase structure of the interstellar medium is maintained.

The authors have measured the reaction propagation rate (RPR) in weapons-grade, ultrafine octahydro-1,3,57-tetranitro-1,3,5,7-tetrazocine (HMX) powder in a diamond anvil cell over the pressure range 0.7-35 GPa. In order to have a cross-comparison of their experiments, they carried out a series of experiments on nitromethane (NM) up to 15 GPa. The results on NM are indistinguishable from previous measurements of Rice and Folz. In comparison to high-pressure, NM, the burn process for solid HMX is not spatially uniform.

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Climate models, numerical weather prediction (NWP) models, and atmospheric dispersion models often rely on parameterizations of planetary boundary layer height. In the case of a stable boundary layer, errors in boundary layer height estimation can result in gross errors in boundary-layer evolution and in prediction of turbulent mixing within the boundary layer.

A neutrino oscillation experiment using the J-PARC SO GeV 0.75 MW proton beam is planned as a successor to the K2K project currently being operated at KEK. A superconducting magnet system is required for the arc section of the primary proton beam line to be within the space available at the site. A system with 28 combined function magnets is proposed to simplify the system and optimize the cost. The required fields for the magnets are 2.6 T dipole and 19 T/m quadrupole. The magnets are also required to have a large aperture, 173.4 mm diameter, to accommodate the large beam emittance. The magnets will be protected by cold diodes and cooled by forced flow supercritical helium produced by a 4.5 K, 2 {approx} 2.5 kW refrigerator. This paper reports the system overview and the design status.

We analyze simulations of present and future climates in the western U.S. performed with four regional climate models (RCMs) nested within two global ocean-atmosphere climate models. Our primary goal is to assess the range of regional climate responses to increased greenhouse gases in available RCM simulations. The four RCMs used different geographical domains, different increased greenhouse gas scenarios for future-climate simulations, and (in some cases) different lateral boundary conditions. For simulations of the present climate, we compare RCM results to observations and to results of the GCM that provided lateral boundary conditions to the RCM. For future-climate (increased greenhouse gas) simulations, we compare RCM results to each other and to results of the driving GCMs. When results are spatially averaged over the western U.S., we find that the results of each RCM closely follow those of the driving GCM in the same region, in both present and future climates. In present-climate simulations, the RCMs have biases in spatially-averaged simulated precipitation and near-surface temperature that seem to be very close to those of the driving GCMs. In future-climate simulations, the spatially-averaged RCM-projected responses in precipitation and near-surface temperature are also very close to those of the respective driving GCMs. Precipitation responses …

Some recent investigations have begun to quantify turbulence and dissipation in frontal zones to address the question of what physical mechanism counteracts the intensification of temperature and velocity gradients across a developing front. Frank (1994) examines the turbulence structure of two fronts that passed a 200m instrumented tower near Karlsruhe, Germany. In addition to showing the mean vertical structure of the fronts as they pass the tower, Frank demonstrates that there is an order of magnitude or more increase in turbulent kinetic energy across the frontal zone. Blumen and Piper (1999) reported turbulence statistics, including dissipation rate measurements, from the MICROFRONTS field experiment, where high-frequency turbulence data were collected from tower-mounted hotwire and sonic anemometers in a cold front and in a density current. Chapman and Browning (2001) measured dissipation rate in a precipitating frontal zone with high-resolution Doppler radar. Their measurements were conducted above the surface layer, to heights of 5km. The dissipation rate values they found are comparable to those measured in Kennedy and Shapiro (1975) in an upper-level front. Here, we expand on these recent studies by depicting the behavior of the fine scales of turbulence near the surface in a frontal zone. The primary objective of …

The authors have measured the reaction propagation rate (RPR) in weapons-grade, ultrafine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) powder in a diamond anvil cell over the pressure range 0.7-35 GPa. In order to have a cross-comparison of their experiments, they carried out a series of experiments on nitromethane (NM) up to 15 GPa. The results on NM are indistinguishable from previous measurements of Rice and Folz. In comparison to high-pressure NM, the burn process for solid HMX is between 5-10 times faster at pressures above 10 GPa.

The population size of genetic algorithms (GAs) affects the quality of the solutions and the time required to find them. While progress has been made in estimating the population sizes required to reach a desired solution quality for certain problems, in practice the sizing of populations is still usually performed by trial and error. These trials might lead to find a population that is large enough to reach a satisfactory solution, but there may still be opportunities to optimize the computational cost by reducing the size of the population. This paper presents a technique called plague that periodically removes a number of individuals from the population as the GA executes. Recently, the usefulness of the plague has been demonstrated for genetic programming. The objective of this paper is to extend the study of plagues to genetic algorithms. We experiment with deceptive trap functions, a tunable difficult problem for GAs, and the experiments show that plagues can save computational time while maintaining solution quality and reliability.

This paper discusses the design of an ultra-compact, Marx-type, high-voltage generator. This system incorporates high-performance components that are closely coupled and integrated into an extremely compact assembly. Low profile, custom ceramic capacitors with coplanar extended electrodes provide primary energy storage. Low-inductance, spark-gap switches incorporate miniature gas cavities imbedded within the central region of the annular shaped capacitors, with very thin dielectric sections separating the energy storage capacitors. Carefully shaped electrodes and insulator surfaces are used throughout to minimize field enhancements, reduce fields at triple-point regions, and enable operation at stress levels closer to the intrinsic breakdown limits of the dielectric materials. Specially shaped resistors and inductors are used for charging and isolation during operation. Forward-coupling ceramic capacitors are connected across successive switch-capacitor-switch stages to assist in switching. Pressurized SF, gas is used for electrical insulation in the spark-gap switches and throughout the unit. The pressure housing is constructed entirely of dielectric materials, with segments that interlock with the low-profile switch bodies to provide an integrated support structure for all of the components. This ultra-compact Marx generator employs a modular design that can be sized as needed for a particular application. Units have been assembled with 4, 10, and 30 stages …

X-ray line emission from 2{ell} - n{ell}{prime} transitions in Ne-like Kr and nearby ions has been observed from {approx} 1 {micro}m Kr clusters irradiated by fs-scale laser pulses at the JAERI facility in Kyoto, Japan. The incident laser intensity reached 10{sup 19} W/cm{sup 2}, with pulse energies from 50 to 300 mJ and pulse durations from 30 to 500 fs. The dependence of the x-ray spectral features and intensity on the incident laser intensity is rather weak, indicating that the 1 - 2 ps cluster lifetimes limit the number of ions beyond Ne-like Kr that can be produced by collisional ionization. Lines from F- to Al-like Kr emitted from the cluster plasmas have been identified using data from the relativistic multiconfiguration atomic structure code FAC. A collisional-radiative model based on this data has been constructed and used to determine that the cluster plasma has electron densities near 10{sup 22} cm{sup -3}, temperatures of a few hundred eV and hot electron fractions of a few percent.

Several recent applications for fast ramped magnets have been found that require precise measurement of the time-dependent fields. In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the typical level of accuracy for accelerators, {Delta} B/B better than 0.01%. To meet this need, we have begun development of a system containing 16 stationary pickup windings that will be sampled at a high rate. It is hoped that harmonics through the decapole can be measured with this system. Precise measurement of the time-dependent harmonics requires that both the pickup windings and the voltmeters be nearly identical. To minimize costs, printed circuit boards are being used for the pickup windings and a combination of amplifiers and ADC's for voltmeters. In addition, new software must be developed for the analysis. The paper will present a status report on this work.

A part of the Nuclear Energy Research Initiative (NERI) is the development of the Small Transportable Autonomous Reactor (STAR) for deployment in countries that do not have a nuclear industry. STARs would have an output of from 100 to 150 MW electric, would be fueled in the country of manufacture, and after 15 to 20 years of operation the reactor core would be returned to the country of manufacture for refueling. A candidate STAR design can be found in (Greenspan, 2000). This paper describes the design of the control and monitoring system that might be used. There are two unique features to this system. One is that the monitored information will be transmitted to a remote site for two purposes, safeguards, and allowing experts a great distance away direct access to view the reactor's operating parameters. The second feature is safeguards sensors will be designed into the system and there will monitoring of the safeguards aspects of the system for tampering. Any safeguards anomalies will be sent to the remote site as alarms. Encrypted satellite communications will be used to transmit the data. These features allow the STAR to be operated by a small staff and will reduce the costs …

We present results from two-dimensional numerical simulations of the interactions between magnetized shocks and radiative clouds. Our primary goal is to characterize the dynamical evolution of the shocked clouds. We perform runs in both the strong and weak magnetic field limits and consider three different field orientations. For the geometries considered, we generally find that magnetic fields external to, but concentrated near, the surface of the cloud suppress the growth of destructive hydrodynamic instabilities. External fields also increase the compression of the cloud by effectively acting as a confinement mechanism driven by the interstellar flow and local field stretching. This can have a dramatic effect on both the efficiency of radiative cooling, which tends to increase with increasing magnetic field strength, and on the size and distribution of condensed cooled fragments. In contrast, fields acting predominately internally to the cloud tend to resist compression, thereby inhibiting cooling. We observe that, even at modest strengths ({beta}{sub o} {approx}< 100), internal fields can completely suppress low-temperature (T < 100 K) cooling.