The accuracy of Cartesian embedded boundary methods for the second order wave equation in general two-dimensional domains subject to Dirichlet boundary conditions is analyzed. Based on the analysis, we develop a numerical method where both the solution and its gradient are second order accurate. We avoid the small-cell stiffness problem without sacrificing the second order accuracy by adding a small artificial term to the Dirichlet boundary condition. Long-time stability of the method is obtained by adding a small fourth order dissipative term. Several numerical examples are provided to demonstrate the accuracy and stability of the method. The method is also used to solve the two-dimensional TM{sub z} problem for Maxwell's equations posed as a second order wave equation for the electric field coupled to ordinary differential equations for the magnetic field.

Daily student newspaper from the University of North Texas in Denton, Texas that includes local, state and campus news along with advertising.

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This report examines the factors that bolster or weaken international relations between the U.S. and Indonesian including the rise of separatist movements and terrorist activities in Indonesia.

We show that a gravitational interaction between the derivative of the Ricci scalar curvature and the baryon-number current dynamically breaks CPT in an expanding universe and, combined with baryon-number-violating interactions, can drive the universe towards an equilibrium baryon asymmetry that is observationally acceptable.

The Lynx arc, with a redshift of 3.357, was discovered during spectroscopic follow-up of the z = 0.570 cluster RX J0848+4456 from the ROSAT Deep Cluster Survey. The arc is characterized by a very red R - K color and strong, narrow emission lines. Analysis of HST WFPC 2 imaging and Keck optical and infrared spectroscopy shows that the arc is an H II galaxy magnified by a factor of {approx} 10 by a complex cluster environment. The high intrinsic luminosity, the emission line spectrum, the absorption components seen in Ly{alpha} and C IV, and the restframe ultraviolet continuum are all consistent with a simple H II region model containing {approx} 10{sup 6} hot O stars. The best fit parameters for this model imply a very hot ionizing continuum (T{sub BB} {approx} 80, 000 K), high ionization parameter (log U {approx} -1), and low nebular metallicity (Z/Z{sub {circle_dot}} {approx} 0.05). The narrowness of the emission lines requires a low mass-to-light ratio for the ionizing stars, suggestive of an extremely low metallicity stellar cluster. The apparent overabundance of silicon in the nebula could indicate enrichment by past pair instability supernovae, requiring stars more massive than {approx}140M{sub {circle_dot}}.

We investigate the Butcher-Oemler effect using samples of galaxies brighter than observed frame K* + 1.5 in 33 clusters at 0.1 {approx}< z {approx}< 0.9. We attempt to duplicate as closely as possible the methodology of Butcher & Oemler. Apart from selecting in the K-band, the most important difference is that we use a brightness limit fixed at 1.5 magnitudes below an observed frame K* rather than the nominal limit of rest frame M(V ) = -20 used by Butcher & Oemler. For an early type galaxy at z = 0.1 our sample cutoff is 0.2 magnitudes brighter than rest frame M(V ) = -20, while at z = 0.9 our cutoff is 0.9 magnitudes brighter. If the blue galaxies tend to be faint, then the difference in magnitude limits should result in our measuring lower blue fractions. A more minor difference from the Butcher & Oemler methodology is that the area covered by our galaxy samples has a radius of 0.5 or 0.7 Mpc at all redshifts rather than R{sub 30}, the radius containing 30% of the cluster population. In practice our field sizes are generally similar to those used by Butcher & Oemler. We find the fraction of …

Press release from the Black Academy of Arts and Letters discussing a film festival featuring actor Tim Reid on March 13, 2004 at the Dallas Convention Center Theatre Complex.

Weekly newspaper from Emory, Texas that includes local, state, and national news along with advertising.

The newly discovered exotic {Theta} baryon of mass 1540 MeV (and very small width) truly has a very low mass, if it is a pentaquark system of even parity. A schematic model in which the coherent interaction of u{bar s} and d{bar s} pairs leads to a very large residual (non-confining) attractive interaction is introduced. This collective vibrational model accounts for the mass and small decay width to the KN channel, but yields a significant coupling to the virtual K*N channel. The schematic model predicts an attractive {Theta}-nucleon interaction strong enough to bind a {Theta} particle to a nucleus in a state that is stable against decay via strong interactions. The discovery of {Theta}-nuclei could be a definitive proof that the {Theta} parity is even.

Extremely large laser power might be obtained by compressing laser pulses through backward Raman amplification (BRA) in plasmas. Premature Raman backscattering of a laser pump by plasma noise might be suppressed by an appropriate detuning of the Raman resonance, even as the desired amplification of the seed persists with a high efficiency. In this paper, we analyze side-scattering of laser pumps by plasma noise in backward Raman amplifiers. Though its growth rate is smaller than that of backscattering, the side-scattering can nevertheless be dangerous, because of a longer path of side-scattered pulses in plasmas and because of an angular dependence of the Raman resonance detuning. We show that side-scattering of laser pumps by plasma noise in BRA might be suppressed to a tolerable level at all angles by an appropriate combination of two detuning mechanisms associated with plasma density gradient and pump chirp.

The purpose of this design calculation is to revise and update the previous criticality evaluation for the fuel handling, transfer and storage operations to be performed in the Surface Facility documented in BSC 2003c. The scope of this design calculation covers the operations in the Dry Transfer Facility (DTF) and Remediation Building (RB) and their processes as established at the date of this calculation. Also, this design calculation focuses on intact commercial spent nuclear fuel (SNF) assemblies, i.e., pressurized water reactor (PWR) and boiling water reactor (BWR) SNF. A description of the changes is as follows: (1) Update the supporting calculations for the various Category 1 and 2 event sequences as identified in the ''Preliminary Categorization of Event Sequences for License Application'' (BSC 2003a, Section 7). (2) Include comments from an informal review conducted by Y-12, located in Oak Ridge, Tennessee (Su 2004). (3) Revise the BWR calculations to reflect a different Boral loading. (4) Assess effects of potential moderator intrusion into the storage rack area with various water levels for defense in depth based on the new design of the DTF and RB.

The objective of this research project was to improve the basis for estimating environmental tobacco smoke (ETS) exposures in a variety of indoor environments. The research utilized experiments conducted in both laboratory and ''real-world'' buildings to (1) study the transport of ETS species from room to room, (2) examine the viability of using various chemical markers as tracers for ETS, and (3) to evaluate to what extent re-emission of ETS components from indoor surfaces might add to the ETS exposure estimates. A three-room environmental chamber was used to examine multi-zone transport and behavior of ETS and its tracers. One room (simulating a smoker's living room) was extensively conditioned with ETS, while a corridor and a second room (simulating a child's bedroom) remained smoking-free. A series of 5 sets of replicate experiments were conducted under different door opening and flow configurations: sealed, leaky, slightly ajar, wide open, and under forced air-flow conditions. When the doors between the rooms were slightly ajar the particles dispersed into the other rooms, eventually reaching the same concentration. The particle size distribution took the same form in each room, although the total numbers of particles in each room depended on the door configurations. The particle number …

This is a multiyear experimental research program that focuses on improving relevant material properties of high-critical temperature (Tc) superconductors and developing fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne National Laboratory (ANL) program.

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.

This report introduces selected basic sources that are useful in obtaining background information or specific facts on the status of federal legislative or regulatory initiatives. It includes telephone, online, and media sources are included, as well as pertinent directories, such as those of organizations that track areas of interest. Annotations describing each source's contents and organization are included so that researchers can select those that most closely fit their needs. Internet addresses usually provide information about the items, rather than access to them.

Recent laser ignition experiments on octahydro-1,3,5,7-tetranitro-1,3,5,7-terrazocine (HMX) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) subjected to laser fluxes ranging from 10 to 800 W/cm{sup 2} produced ignition times from seconds to milliseconds. Global chemical kinetic thermal decomposition models for HMX and TATB have been developed to calculate times to thermal explosion for experiments in the seconds to days time frame. These models are applied to the laser ignition experimental data in this paper. Excellent agreement was obtained for TATB, while the calculated ignition times were longer than experiment for HMX at lower laser fluxes. At the temperatures produced in the laser experiments, HMX melts. Melting generally increases condensed phase reaction rates so faster rates were used for three of the HMX reaction rates. This improved agreement with experiments at the lower laser fluxes but yielded very fast ignition at high fluxes. The calculated times to ignition are in reasonable agreement with the laser ignition experiments, and this justifies the use of these models for estimating reaction times at impact and shock ''hot spot'' temperatures.

A research effort performed by the Target Fabrication Group has developed a method for producing precision, meso-scale gold support rings for laser targets. Many different laser targets consist of planar components that are built upon a gold support ring, such as the HyDiv and RadG targets shown in Figure 1. Because of the sequence in which laser targets such as these must be built to achieve the required overall precision, the washer-shaped support rings must fit precisely onto fixtures that are used throughout the manufacturing process. Because the support ring is the fundamental structure onto which the target is built, any imprecision in the support ring propagates through the entire target. Thus, even if the physics performance of a laser target does not require a flat and precise support ring, the manufacturing methods used to achieve the overall level of precision demanded in the targets rely heavily on the precision of the support rings. Past efforts to purchase gold support rings from outside vendors have been either extremely costly, or the vendors were unable to deliver acceptable parts. On several occasions, difficulties in obtaining acceptable support rings in a timely manner have compromised the ability to manufacture and deliver targets …

Various aspects of the Laboratory's national security mission are now highly dependent on accurate computer code simulations of plastic flow (i.e., non-reversible deformation) of materials under conditions of high hydrostatic pressure. Strength models are typically dependent on pressure, temperature, and strain rate. Current strength models can not be extrapolated to high pressure because they are not based on the underlying mechanisms of plastic deformation. The critical need for predictive models of material strength, which describe flow stress in computer code simulations, has motivated LLNL's multiscale modeling efforts. Over the past three years, the ''Material Strength at High Pressure'' LDRD Strategic Initiative has established a framework for the development of predictive strength models for deformation of metals under conditions of high hydrostatic pressure. Deformation experiments have been developed to measure the effect of high pressure on the yield strength and work hardening behavior of high purity Mo and Ta single crystals. The over arching goal of the SI is to experimentally validate multiscale-modeling capabilities for deformation of metals under conditions of high pressure. The work performed and accomplished is a necessary next step in the development of predictive strength models. Our initial experimental results show that the influence of pressure is …

Most chemically stable organic materials age through changes on the mesoscopic scale (from 10 nm to 10 mm). Examples include the slow crystallization of polymers, changes in particle size distributions with age, and the swelling of pressed powders. We began the Mesochem project to develop a new mesoscopic modeling capability for organic materials, including polymers, molecular crystals, and filled polymer composites. Our goal was to develop and validate novel mesoscopic modeling techniques that are well suited for materials of interest to LLNL's nation security mission, such as high explosives, binding agents, and foams.

The National Museum of the Pacific War presents an oral interview with Tom D. Ellison. Ellison was born 14 August 1925 in Sierra Blanca, Texas. He joined the Navy in September 1942. After 12 weeks of boot camp at the Farragut Naval Training Center, Idaho, he went for 21 weeks of aircraft maintenance training in Norman, Oklahoma, and 4 weeks of air gunnery training in Purcel, Oklahoma. This was followed by more maintenance and gunnery training at NAS Jacksonville. Next it was to NAS Oceana, Virginia working on and flying in PB4Y patrol planes. Ellison then sailed to England on the USS Matagorda (AVP-22). He spent from December 1943 to August 1945 at Dunkeswell Airfield in Devon. His squadron, VP-105, performed anti-submarine patrols in the English Channel and the North Sea. Following the German surrender, Ellison went to San Diego, Guam, Japan, and finally Shanghai, China to join a PBM Mariner squadron operating from a seaplane tender in the Whangpoo River. They provided passenger, mail, and air-sea rescue services in the area. Having advanced to AMM 1/C, Ellison was discharged from the Navy in San Diego.

The National Museum of the Pacific War presents an oral interview with McGehee Word.. Word enlisted in the Army Air Corps flying cadet program in 1940 when he was 26 years old. Along the way, he was trained as a B-17 pilot and was sent overseas to England, via Africa, and was assigned to the 92nd Bomb Group, 326th Bomb Squadron. While stationed in England, Word had an encounter with J. Frank Dobie. Word returned to the US in November, 1944 after 32 missions. He was training in B-29 bombers when the war ended.

Interview with Buck A. Young, a radar bombadier in the US Air Force. He answers questions about his time in the military during WWII and the Vietnam War.

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.