Article discussing artificial intelligence, libraries, and information retrieval.

Article on direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon.

Article discussing an ab initio study of methane activation by group IVB imido complexes.

Article discussing a wide range of transition metal imido (TMI) complexes using ab initio molecular orbital (MO) calculations.

Article on high-valent transition-metal alkylidene complexes and the effect of ligand and substituent modification.

Article on semiclassical chaos, the uncertainty principle, and quantum dissipation.

Article on phonon softening and high-pressure low-symmetry phases of cesium iodide.

Article on the utilization of cyanide as a nitrogenous substrate by Pseudomonas fluorescens NCIMB 11764 and evidence for multiple pathways of metabolic conversion.

Article on the spectroscopic properties of polycyclic aromatic compounds and an examination of nitromethane as a selective fluorescence quenching agent for alternant polycyclic aromatic nitrogen hetero-atom derivatives.

Article on a spectroscopic investigation of fluorescence quenching agents and the effect of nitromethane on the fluorescence emission behavior of select cyclopenta-PAH, aceanthrylene, and fluorene derivatives.

Article discussing thermodynamic properties of organic compounds and combustion and sublimation enthalpies of 2,4,6-trimethylbenzonitrile N-oxide.

Newspaper article about an upcoming Harvey Girls luncheon put on by the Temple, Texas Railroad and Pioneer Museum. The article was sent by Joe W. Zvolanek to Rosa Walston Latimer.

Newspaper article about Lillian Preas, a resident of Brownwood, Texas and former Harvey Girl whose story was used in the magazine Texas Highways.

Article on an ab initio study of sulfinic acid and related species.

Article on kinetic studies of the reactions of atomic chlorine and bromine with silane.

Article on kinetics studies of the reactions of atomic chlorine and bromine with trimethylsilane and an ab initio investigation.

We present a preliminary measurement of R{sub b}, the ratio of {Gamma}(Z{degree} - b{bar b}) relative to {Gamma}(Z{degree} {yields} hadrons) using the silicon CCD-pixel vertex detector of the SLD at the SLAC Linear Collider (SLC). An impact parameter method and a displaced vertex method are applied to all charged tracks, to efficiently tag Z{degree} - b{bar b} events. From the impact (displaced vertex) approach we find R{sub b} = 0.214 {plus_minus} 0.010 {plus_minus} 0.025 (R{sub b} = 0.204 {plus_minus} 0.010 {plus_minus} 0.030), consistent with the standard model value.

Lithologic variation, regional depositional trends, and the lack of written guidelines have resulted in inconsistencies in the recognition of stratigraphic contacts in drill holes at the Nevada Test Site (NTS). Stratigraphic identification, based on mineralogy of discrete samples, can be augmented by geophysical logs and downhole movies to more accurately and consistently locate contacts between units. Criteria are established for locating the base of the Pahute Mesa ash-flow tuff, the top of the Ammonia Tanks ash-flow tuff, the top of the Ammonia Tanks bedded tuff, and the top and the base of the Rainier Mesa Tuff.

The concept of a disturbed zone surrounding the mined openings of a potential geologic repository for high-level radioactive waste was introduced by the US Nuclear Regulatory Commission (NRC) as a region to be excluded for determining groundwater travel time to the accessible environment, but to be included for determining the impact of underground construction and radioactive decay heat on groundwater movement and radionuclide transport for total system performance analysis. This paper explores both the regulatory and technical necessity for characterizing and modeling a larger region -- the altered zone -- within which the temperature is increased significantly by heat from the high-level waste. Particular attention is given to addressing the effects of heterogeneity on groundwater flux and travel time, showing how these effects might be modeled simply on a macroscopic scale, and outlining its parameters. The effect of uncertainty in the parameter values on the performance of a potential repository can then be easily handled by probabilistic analysis.

Fracture-mechanics crack growth tests were conducted on 25.4-mm-thick compact tension specimens of Types 304L and 316L Stainless steel and Incoloy 825 at 93{degrees}C and 1 atmosphere of pressure in simulated J-13 well water, which is representative of the groundwater at the Yucca Mountain site in Nevada that is proposed for a high-level nuclear waste repository. Crack growth rates were measured under various load conditions: load ratios of 0.2--1.0, frequencies of 2 {times} 10{sup {minus}4}{minus}1 Hz, rise times of 1--5000 s, and peak stress intensities of 25--40 MPa{center_dot}m{sup {1/2}}. The measured crack growthrates are bounded by the predicted rates from the current ASME Section 11 correlation for fatigue crack growth rates of austenitic stainless steel in air. Environmentally accelerated crack growth was not evident in any of the three materials under the test conditions investigated.

We report the results of preliminary studies of a 2 to 4 nm SASE FEL, using a photoinjector to produce the electron beam, and the SLAC linac to accelerate it to an energy up to 10 GeV. Longitudinal bunch compression is used to increases ten fold the peak current to 2.5 kA, while reducing the bunch length to the subpicosecond range. The saturated output power is in the multi-gigawatt range, producing about 10{sup 14} coherent photons within a bandwidth of about 0.2% rms, in a pulse of several millijoules. At 120Hz repetition rate the average power is about 1 W. The system is optimized for x-ray microscopy in the water window around 2 to 4 nm, and will permit imaging a biological sample in a single subpicosecond pulse.

An attempt is made at illustrating the many contributions to rock mechanics from US defense programs, over the past 30-plus years. Large advances have been achieved in the technology-base area covering instrumentation, material properties, physical modeling, constitutive relations and numerical simulations. In the applications field, much progress has been made in understanding and being able to predict rock mass behavior related to underground explosions, cratering, projectile penetration, and defense nuclear waste storage. All these activities stand on their own merit as benefits to national security. But their impact is even broader, because they have found widespread applications in the non-defense sector; to name a few: the prediction of the response of underground structures to major earthquakes, the physics of the earth`s interior at great depths, instrumentation for monitoring mine blasting, thermo-mechanical instrumentation useful for civilian nuclear waste repositories, dynamic properties of earthquake faults, and transient large-strain numerical modeling of geological processes, such as diapirism. There is not pretense that this summary is exhaustive. It is meant to highlight success stories representative of DOE and DOD geotechnical activities, and to point to remaining challenges.

In August 1988, two years after the Chernobyle accident, the United States and the Soviet Union signed an agreement to sponsor a Joint coordinating Committee on Civilian Nuclear Reactor Safety, (JCCCNRS). The Soviet Union agreed to provide some information on late effects of radiation exposures and to attempt to add some new insights into low dose and low dose rate radiation consequences. At that time, it had just been revealed that significant radiation exposures had occurred in the South Ural Mountains, associated with the early years of operation of the MAYAK nuclear complex. The need to be able to better predict the long term consequences of overexposures, such as occurred with the Chernobyl accident, was a major factor in organizing this workshop. We decided to invite a small number of experts from the Soviet Union, who had direct knowledge of the situation. A small group of American experts was invited to help in a discussion of the state of knowledge of continual low level exposure. The experts and expertise included: Aspects of bask theoretical radiobiological models, studies on experimental animals exposed to chronic or fractionated external or internal radiation, studies on populations exposed to chronic intake and continual exposures, workers …

Various commercial software packages and customized programs provide the ability to analyze and visualize the geology of Yucca Mountain. Starting with sparse, irregularly spaced data a series of gridded models has been developed representing the thermal/mechanical units within the mountain. Using computer aided design (CAD) software and scientific visualization software, the units can be manipulated, analyzed, and graphically displayed. The outputs are typically gridded terrain models, along with files of three-dimensional coordinates, distances, and other dimensional values. Contour maps, profiles, and shaded surfaces are the output for visualization.