We have examined the mechanical response of unalloyed Ta and Ta-W alloy annealed plates over a wide range of loadings. It was observed in general that Ta exhibits nonuniform mechanical behavior, for example, hourglassing of compression samples and multiple instabilities during tensile deformation. In contrast, the Ta-W alloys do not exhibit any unusual nonuniform behavior. This work presents data revealing the spatial distribution of texture in Ta and Ta-W alloys. Significant variations in texture both through the thickness and from one area of the plate to another were found to be characteristic of Ta. The dominant feature of the texture variations was found to be enhanced <111> crystal direction fractions at the center of the plate, with a decreasing fraction near the surface. We find that the variation in texture in the Ta-W alloys is substantially less than that seen in Ta with primarily a <100> cube texture throughout. This study suggest that the texture gradients are responsible for the nonuniform mechanical response of Ta and that the uniform behavior of the Ta-W alloys is a consequence of the absence of texture gradients.

Ion implantation of O into Al and growth of Al(O) layers using electro-cyclotron resonance plasma and pulsed laser depositions produce composite alloys with a high density of nanometer-size oxide precipitates in an Al matrix. The precipitates impart high strength to the alloy and reduced adhesion during sliding contact, while electrical conductivity and ductility are retained. Implantation of N into Al produces similar microstructures and mechanical properties. The athermal energies of deposited atoms are a key factor in achieving these properties.

Methods for limiting the size of hadronic spin-flip in the Coulomb- Nuclear Interference. region are critically assessed. This work was presented at the High Energy Polarimetry Workshop in Amsterdam, Sept. 9, 1996 and the RHIC Spin Collaboration meeting in Marseille, Sept. 17, 1996.

We explore the capability of a 500 or 1000 GeV e{sup +} e{sup {minus}} linear collider to measure anomalous quartic gauge boson couplings. In the framework of a non-linear effective Lagrangian with a custodial SU(2) symmetry, there are only two next-to-leading order operators which contribute to quartic, but not to two- and three-gauge boson interactions. The limits on the coefficients of these operators from present and future e{sup +} e{sup {minus}} colliders are compared with those available from other sources.

We present a general phenomenological analysis of a class of Two Higgs Doublet Models with Flavor Changing Neutral Currents arising at the tree level. The existing constraints mainly affect the couplings of the first two generations of quarks, leaving the possibility for non negligible Flavor Changing couplings of the top quark open. The next generation of lepton and hadron colliders will offer the right environment to study the physics of the top quark and to unravel the presence of new physics beyond the Standard Model. In this context we discuss some interesting signals from Flavor Changing Scalar Neutral Currents.

This report contains the proceedings of the Imaging Sciences Workshop sponsored by C.A.S.LS., the Center for Advanced Signal & Image Sciences. The Center, established primarily to provide a forum where researchers can freely exchange ideas on the signal and image sciences in a comfortable intellectual environment, has grown over the last two years with the opening of a Reference Library (located in Building 272). The Technical Program for the 1996 Workshop include a variety of efforts in the Imaging Sciences including applications in the Microwave Imaging, highlighted by the Micro-Impulse Radar (MIR) system invented at LLNL, as well as other applications in this area. Special sessions organized by various individuals in Speech, Acoustic Ocean Imaging, Radar Ocean Imaging, Ultrasonic Imaging, and Optical Imaging discuss various applica- tions of real world problems. For the more theoretical, sessions on Imaging Algorithms and Computed Tomography were organized as well as for the more pragmatic featuring a session on Imaging Systems.

The Transportable Vitrification System (TVS) is a large-scale, fully-integrated, transportable, vitrification system for the treatment of low-level nuclear and mixed wastes in the form of sludges, soils, incinerator ash, and similar waste streams. The TVS was built to demonstrate the vitrification of actual mixed waste at U. S. Department of Energy (DOE) sites. Currently, Westinghouse Savannah River Company (WSRC) is working with Lockheed Martin Energy Systems (LMES) to apply field scale vitrification to actual mixed waste at Oak Ridge Reservation`s (ORR) K-25 Site. Prior to the application of the TVS to actual mixed waste it was tested on simulated K-25 B and C Pond waste at Clemson University. This paper describes the results of that testing and preparations for the demonstration on actual mixed waste.

Several tools have been developed at the Savannah River Site (SRS) to remotely sample stored radioactive waste. These sampling tools have been developed to determine the chemical characteristics of the waste prior to processing. The processing of waste material varies according to the chemical characteristics of the waste, which change due to additions, settling, mixing, and chemical reactions during storage. Once the waste has been sampled to identify its characteristics, the chemical composition of the waste can then be altered if needed to prepare for processing. Various types of waste material in several types of containment must be sampled at SRS. Stored waste materials consist of liquids, floating organics, sludge, salt and solids. Waste is stored in four basic types of tanks with different means of access and interior obstructions. The waste tanks can only be accessed by small openings: access ports, risers and downcomers. Requirements for sampling depend on the type of tank being accessed, the waste within the tank, and the particular location in the tank desired for taking the sample. Sampling devices have been developed to sample all of the waste material forms found in the SRS tank farms. The fluid type samplers are capable of sampling …

Nonabsorbing defects can lead to laser damage. Defects such as voids, microcracks, and localized stressed concentrations, even if they differ from the surrounding medium only by refractive index, can serve as positive or negative lenses for the incident laser light. The resulting interference pattern between refracted and diffracted light can result in intensity increases on the order of a factor of 2 some distance away from a typical negative microlens, and even larger for a positive microlens. Thus, the initial damage site can be physically removed from the defect which initiates damage. The parameter that determines the strength of such lensing is (Ka){sup 2}{Delta}{epsilon}, where the wavenumber K is 2{pi}/{lambda}, 2a is the linear size of the defect, and {Delta}{epsilon} is the difference in dielectric coefficient between matrix and scatterer. Thus, even a small change in refractive index results in a significant effect for a defect large compared to a wavelength. Geometry is also important. Three dimensional (e.g. voids) as well as linear and planar (e.g. cracks) microlenses can all have strong effects. This paper evaluates intensification due to spherical voids and high refractive index inclusions.

The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, …

This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model.

The Los Alamos National Laboratory (LANL) Decommissioning Program has decontaminated and demolished two filter plenum buildings at Technical Area 21 (TA-21). During the project a former hot cell was retrofitted to perform decontamination and size reduction of highly Pu contaminated process exhaust (1,100 ft) and gloveboxes. Pu-238/239 concentrations were as high a 1 Ci per linear foot and averaged approximately 1 mCi/ft. The Project decontamination objective was to reduce the plutonium contamination on surfaces below transuranic levels. If possible, metal surfaces were decontaminated further to meet Science and Ecology Group (SEG) waste classification guidelines to enable the metal to be recycled at their facility in oak Ridge, Tennessee. Project surface contamination acceptance criteria for low-level radioactive waste (LLRW), transuranic waste, and SEG waste acceptance criteria will be presented. Ninety percent of all radioactive waste for the project was characterized as LLRW. Twenty percent of this material was shipped to SEG. Process exhaust and glove boxes were brought to the project decontamination area, an old hot cell in Building 4 North. This paper focuses on process exhaust and glovebox decontamination methodology, size reduction techniques, waste characterization, airborne contamination monitoring, engineering controls, worker protection, lessons learned, and waste minimization. Decontamination objectives are …

We have measured gain and saturation in sing;e mode Yb:silica fiber, and developed fiber lasers and amplifiers at 1053 nm. The lasers are tunable over 10`s of nanometers, with amplifier gain flattened by fiber gratings or dielectric filters.

Guidelines for writing a decision paper are presented. The purpose of the decision paper is to present complex issues in an organized format; it is especially helpful when timeliness is important. The writing style and format of the decision paper are described. The format for a decision paper includes the issue or problem statement, relevant background material, options or alternatives, discussion, recommendation, coordination/endorsement, and record of decision.

Finite element methods (FEM) are demonstrated in combination with large-eddy simulations (LES) as a valuable tool for the study of turbulent, separating channel flows, specifically the flow over a backward facing step.

This work sought to improve the communication between users and makers of fine diamond grinding wheels. A promising avenue for this is to formulate a voluntary product standard that comprises performance indicators that bridge the gap between specific user requirements and the details of wheel formulations. We propose a set of performance specifiers of figures-of-merit, that might be assessed by straightforward and traceable testing methods, but do not compromise proprietary information of the wheel user of wheel maker. One such performance indicator might be wheel hardness. In addition we consider technologies that might be required to realize the benefits of optimized grinding wheels. A non-contact wheel-to- workpiece proximity sensor may provide a means of monitoring wheel wear and thus wheel position, for wheels that exhibit high wear rates in exchange for improved surface finish.

Article on the solubility of pyrene in binary alcohol + cyclohexanol and alcohol + 1-pentanol solvent mixtures at 299.2 K.

A generalized Wakimoto realization of $\widehat\cal G_K$ can be associated with each parabolic subalgebra $\cal P=(\cal G_0 +\cal G_+)$ of a simple Lie algebra $\cal G$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconventional viewpoint. An explicit formula is derived for the Wakimoto current first at the Poisson bracket level by Hamiltonian symmetry reduction of the WZNW model. The quantization is then performed by normal ordering the classical formula and determining the required quantum correction for it to generate $\widehat\cal G_K$ by means of commutators. The affine-Sugawara stress-energy tensor is verified to have the expected quadratic form in the constituents, which are symplectic bosons belonging to $\cal G_+$ and a current belonging to $\cal G_0$. The quantization requires a choice of special polynomial coordinates on the big cell of the flag manifold $P\backslash G$. The effect of this choice is investigated in detail by constructing quantum coordinate transformations. Finally, the explicit form of the screening charges for each generalized Wakimoto realization is determined, and some applications are briefly discussed.

Newspaper article from The Houston Chronicle, discussing new evidence uncovered about the beginning of the Holocaust in 1941.

We are using the approach acoustic emission (AE) signal during a grinding operation to detect the proximity of the grinding wheel relative to a brittle material workpiece and are using this detection as a feed- back control signal in our CNC. The repeatability of the AE signal during the wheel approach is the key that allows AE to be used as a proximity detector and is demonstrated at LLNL to be about mm. We noted significant changes of the AE signal as process parameters are modified, but conclude that with a quick CNC calibration routine and holding the parameters constant during a given operation, the AE system can be successfully used to sense pre- contact wheel- to- workpiece separation. Additionally, the AE sensing system allows real- time monitoring during grinding to provide in- process information. The first prototype of an AE system on a commercially available generator is currently be tested at the Center for Optics Manufacturing.

We have used a two step (low and high temperature) strain-annealing process to evolve the two grain boundary character distribution (GBCD) in fully recrystallized oxygen (OFE) copper bar that was forged and rolled. Orientation imaging microscopy (OIM) has been used to characterize the GBCD after each step in the processing. The fraction of special grain boundaries, special fraction was about 70% in the starting recrystallized material. Three different processing conditions were employed: high, moderate, and low temperature. The high temperature process resulted in a reduction in the fraction of special grain boundaries while both of the lower temperature processes resulted in an increase in special fraction up to 85%. Further, the lower temperature processes resulted in average deviation angles from exact misorientation, for special boundaries, that were significantly smaller than observed from the high temperature process. Results indicate the importance of low temperature part of the two-step strain-annealing process in preparing the microstructure for the higher-temperature anneal and commensurate increase in the special fraction.

Several years ago, it was proposed that a dense nonneutral plasma could be produced in a Penning trap. Nonneutral plasmas have excellent confinement. Thus, such a dense plasma might produce simultaneously high density and good confinement (as needed for fusion). Recently, this theoretical conjecture has been demonstrated in a small (3 mm radius) electron experiment (PFX). Densities up to 35 times the Brillouin density (limiting number density in a static trap) have been inferred from the observed strong (100:1) spherical focussing. Electrons are injected at low energy from a single pole of the sphere. A surprising observation is the self-organization of the system into a spherical state, which occurs precisely when the trap parameters are adjusted to produce a spherical well. This organization is observed by a bootstrapping which produces a hysteresis. Additional observations which confirm the dense spherical focus are energy-scattered electrons and deflections of an electron probe beam by the space charge of the central focus.

In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called imprint. These non nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I=10X13 W/cm3. The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of 10 nm RMS. Modulation growth was examined using the Haan model, with linear growth as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two- dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved.

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, …