We have calculated the resonant transfer and excitation cross sections in collisions of U{sup q+} (q = 82, 89, 90) ion with H{sub 2}, He and C in impulse approximation using the multi-configuration Dirac-Fock method. The calculations were carried out in intermediate coupling with configuration interaction. The quantum electrodynamic and finite nuclear size corrections were included in the calculations of transition energies. The Auger rates were calculated including the contributions from Coulomb as well as the transverse Breit interactions. For U{sup 89+} and U{sup 90+}, effects of relatively not only shift the peak positions but also change the peak structure. The total dielectronic recombination strength has been found to increase by 50% due to the effects of relativity. The present theoretical RTEX cross sections for U{sup 90+} in hydrogen agree well with experiment. For U{sup 82+}, Breit interaction had been found to have little effect on the RTEX cross sections involving L-shell excitation. However, the spin-orbit interaction can still make significant change in the peak structure. 24 refs., 4 figs.

Using two argon-ion lasers to pump a CW Ti:Sapphire laser we have demonstrated consistent high power (19 watts) operation with a low order spatial mode. Thermal lensing effects were controlled by enclosing the laser in a vacuum and cooling the rod with liquid nitrogen. Using this laser we also demonstrated a CW Ti:Sapphire amplifier with an efficiency of 20%. 5 refs., 5 figs.

Decontamination and dismantlement (D&D) tasks have been successfully completed on Plant 7 at the Fernald Environmental Management Project. The seven story facility was radiologically, chemically, and biologically contaminated. The work involved the D&D work beginning with safe shutdown and gross decontamination, and ended with removal of the structural steel. A series of lessons learned were gained which include use of explosives, bidding tactics, safe shutdown, building decontamination and lockdown, use of seam climbers, etc.

The monochromatic opacity, {kappa}{sub v}, quantifies the property of a material to remove energy of frequency v from a radiation field. A harmonic average of {kappa}{sub v}, known as the Rosseland mean, {kappa}{sub R}, is frequently used to simplify the calculation of energy transport in stars. The term ''opacity'' is commonly understood to refer to {kappa}{sub R}. Opacity plays an important role in stellar modeling because for most stars radiation is the primary mechanism for transporting energy from the nuclear burning region in the core to the surface. Depending on the mass, convection and electron thermal conduction can also be important modes of stellar energy transport. The efficiency of energy transport is related to the temperature gradient, which is directly proportional to the mean radiative opacity in radiation dominated regions. When the radiative opacity is large, convection can become the more efficient energy transport mechanism. Electron conductive opacity, the resistance of matter to thermal conduction, is inversely proportional to electron thermal conductivity. Thermal conduction becomes the dominant mode of energy transport at high density and low temperature.

Article on laser-induced fluorescence and mass spectrometric studies of the Cu + HCl reaction over a wide temperature range and the formation of HCuCl.

This article critically examines a two-step solvational model for mathematically describing the spectral properties of the DImroth-Reichardt betaine dye ET in binary aqueous-organic solvent mixures.

The Savannah River Site (SRS) has upgraded its aqueous emergency response capability to model the transport of pollutants released from SRS facilities during normal operation or accidents through onsite streams to the Savannah River. The transport and dispersion modules from the US Environmental Protection Agency (EPA) WASP5 model were incorporated into the SRS emergency response system, called the Weather Information and Display (WIND) System. WASP5 is a water quality analysis program that simulates surface water pollutant transport, using a finite difference method to solve the advective transport equation. Observed tritium concentrations in the SRS streams and the Savannah River from an accidental release from K-Reactor, one of the SRS nuclear material production reactors, were used to benchmark the new model. Although all SRS reactors have since been deactivated, this release of tritiated water occurred between December 22 and 25, 1991, through the K-Reactor secondary cooling water discharge. Analyses of reactor discharge water suggested the leak began sometime during December 22. The leak was positively identified and isolated on December 25. Following the release, tritium concentrations were tracked and measured as the tritiated water flowed from the K-Area outfall into Indian Grave Branch and pen Branch, through the Savannah River swamp, …

This paper presents aspects of DOE`s demonstration of compliance with the EPA regulation of the Waste Isolation Pilot Plant (WIPP). The WIPP, a geologic repository for transuranic (TRU) waste, is located 2150 feet below the ground surface in a bedded salt formation about 20 miles east of Carlsbad, NM. Performance of the WIPP as a repository requires that releases to the accessible environment not exceed the limits of the regulation 40 CFR Part 191(1) either when the WIPP is undisturbed, or if there is intrusion into the repository by drilling. In 1996, the EPA promulgated 40 CFR Part 194(2): the implementing regulation for 40 CFR Part 191. The regulatory subsection addressed here, 40 CFR 194.24(b), directs the DOE to identify and analyze the components and characteristics of the TRU waste that can impact performance of the WIPP repository, and thereby possibly impact waste containment. DOE must also analyze those waste characteristics and components that will not affect repository performance.

Lawrence Livermore National Laboratory (LLNL) and Technic, Inc. have entered into a CRADA (Cooperative Research and Development Agreement) with the goal of providing industry with an environmentally benign alternative to the presently used silver cyanide plating process. This project has been in place for about six months and results are quite promising. The main objective, that of deposition of deposits as thick as 125 um (5 mils), has been met. Property data such as stress and hardness have been obtained and the structure of the deposit has been analyzed via metallography and x-ray diffraction. These results will be presented in this paper, along with plans for future work.

The development of a high current, heavy-ion beam driver for inertial confinement fusion requires a detailed understanding of the behavior of the beam, including effects of the strong self-fields. The necessity of including the self-fields of the beam makes particle-in-cell (PIC) simulation techniques ideal, and for this reason, the multi-dimensional PIC/accelerator code WARP has been developed. WARP has been used extensively to study the creation and propagation of ion beams both in experiments and for the understanding of basic beam physics. An overview of the structure of the code will be presented along with a discussion of features that make the code an effective tool in the understanding of space-charge dominated beam behavior. Much development has been done on WARP increasing its flexibility and generality. Major additions include a generalized field description, an efficient steady-state modelling technique, a transverse slice model with a bending algorithm, further improvement of the parallel processing version, and capabilities for linking to chamber transport codes. With these additions, the capability of modeling a large scale accelerator from end-to-end comes closer to reality.

For several reasons, Bayesian parameter estimation is superior to other methods for inductively learning a model for an anticipatory system. Since it exploits prior knowledge, the analysis begins from a more advantageous starting point than other methods. Also, since "nuisance parameters" can be removed from the Bayesian analysis, the description of the model need not be as complete as is necessary for such methods as matched filtering. In the limit of perfectly random noise and a perfect description of the model, the signal-to-noise ratio improves as the square root of the number of samples in the data. Even with the imperfections of real-world data, Bayesian methods approach this ideal limit of performance more closely than other methods. These capabilities provide a strategy for addressing a major unsolved problem in pump operation: the identification of precursors of cavitation. Cavitation causes immediate degradation of pump performance and ultimate destruction of the pump. However, the most efficient point to operate a pump is just below the threshold of cavitation. It might be hoped that a straightforward method to minimize pump cavitation damage would be to simply adjust the operating point until the inception of cavitation is detected and then to slightly readjust the …

Beam-steering algorithms are proposed for a small recirculating induction accelerator being built at the Lawrence Livermore National Laboratory. The principal problem is that the transverse position and velocity of the beam must be inferred from capacitive position monitors, and this determination is complicated by the limited probe resolution and by the lattice errors within steering modules. The fluid/envelope code CIRCE is used to evaluate these algorithms.

AISI 1020 carbon steel was exposed to air at various relative humidities at 65{degrees}C. A ``critical relative humidity`` (CRH) of 75--85% was determined. The CRH is the transitional relative humidity where oxidation/corrosion changes from dry oxidation to aqueous film electrochemical corrosion. Short term testing suggests that aqueous film electrochemical corrosion results in the formation of an inner oxide of Fe{sub 3}O{sub 4}, and an outer oxide of a powdery Fe{sub 2}O{sub 3} and/or Fe{sub 2}O{sub 3}{center_dot}xH{sub 2}O.

Rosen's modeling relation is embedded in Popper's three worlds to provide an heuristic tool for model building and a guide for thinking about complex systems. The utility of this construct is demonstrated by suggesting a solution to the problem of pseudo science and a resolution of the famous Bohr-Einstein debates. A theory of bizarre systems is presented by an analogy with entangled particles of quantum mechanics. This theory underscores the poverty of present-day computational systems (e.g., computers) for creating complex and bizarre entities by distinguishing between mechanism and organism.

Several studies have suggested that the uniformity of Cadmium Zinc Telluride (CZT) detectors play an important role in their performance when operated as gamma-ray spectrometers. However the detailed gamma response of simple planar detectors as a function of position over the device area is largely unknown. To address this issue the authors have built a system capable of measuring the detector response with a resolution of {approximately}250 {micro}m. The system consists of a highly collimated ({approximately}200 {micro}m) photon source (<150 kev) scanned over the detector using a computer controlled two-axis translation stage. Fifteen samples configured as planar detectors were examined with the new apparatus. The material grade of the detectors examined varied from counter to select discriminator. Two classes of spatial response variation were observed and are presented here. Infrared (IR) transmission images were also acquired for each sample and correlation between features in the pulse height spectrum and crystalline defects were observed.

Resistivity results from a 48x48 pixelated CdZnTe (CZT) radiation detector array are presented alongside X-ray topography and detector mapping with a collimated gamma-ray beam. By using a variety of measurements performed on the same sample and registering each data set relative to the others, the spatial dependence of relationships between them was examined. The local correlations between resistivity and one measure of detector performance were strongly influenced by the positions of grain boundaries and other gross crystal defects in the sample. These measurements highlight the need for material studies of spatially heterogeneous CZT to record position information along with the parameters under study.