The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

Demonstration of Argonne National Laboratory's electrometallurgical treatment of spent nuclear fuel is currently being conducted on irradiated, metallic driver fuel and blanket fuel elements from the Experimental Breeder Reactor-II (EBR-II) in Idaho. The residual metallic material from the electrometallurgical treatment process is consolidated into an ingot, the metal waste form (MWF), by employing an induction furnace in a hot cell. Scanning electron microscopy (SEM) and chemical analyses have been performed on irradiated cladding hulls from the driver fuel, and on samples from the alloy ingots. This paper presents the microstructures of the radioactive ingots and compares them with observations on simulated waste forms prepared using non-irradiated material. These simulated waste forms have the baseline composition of stainless steel - 15 wt % zirconium (SS-15Zr). Additions of noble metal elements, which serve as surrogates for fission products, and actinides are made to that baseline composition. The partitioning of noble metal and actinide elements into alloy phases and the role of zirconium for incorporating these elements is discussed in this paper.

Microfluidic devices with microelectrodes have the potential to enable studies of phenomena at size scales where behavior may be dominated by different mechanisms than at macroscales. Through our work developing microfluidic devices for dielectrophoretic separation and sensing of cells and particles, we have fabricated devices from which general or more specialized research devices may be derived. Fluid channels from 80 {micro}m wide X 20 {micro}m deep to 1 mm wide to 200 {micro}m deep have been fabricated in glass, with lithographically patterned electrodes from 10 to 80 {micro}m wide on one or both sides on the channels and over topographies tens of microns in heights. the devices are designed to easily interface to electronic and fluidic interconnect packages that permit reuse of devices, rather than one-time use, crude glue-based methods. Such devices may be useful for many applications of interest to the electrochemical and biological community.

As part of Argonne National Laboratory`s Fuel Conditioning Facility (FCF), a computer-based Mass-Tracking (MTG) System has been developed. The MTG System collects, stores, retrieves and processes data on all operations which directly affect the flow of process material through FCF and supports such activities as process modeling, compliance with operating limits (e.g., criticality safety), material control and accountability and operational information services. Its architecture is client/server, with input and output connections to operator`s equipment-control stations on the floor of FCF as well as to dumb terminals and terminal emulators. Its heterogeneous database includes a relational-database manager as well as both binary and ASCII data files. The design of the database, and the software that supports it, is based on a model of discrete accountable items distributed in space and time and constitutes a complete historical record of the material processed in FCF. Although still under development, much of the MTG system has been qualified and is in production use.

The US Department of Energy (DOE) National Center of Excellence for Metals Recycle has recently been established. The vision of this new program is to develop a DOE culture that promotes pollution prevention by considering the recycle and reuse of metal as the first and primary disposition option and burial as a last option. The Center of Excellence takes the approach that unrestricted release of metal is the first priority because it is the most cost-effective disposition pathway. Where this is not appropriate, restricted release, beneficial reuse, and stockpile of ingots are considered. Current recycling activities include the sale of 40,000 tons of scrap metal from the East Tennessee Technology Park (formerly K-25 Plant) K-770 scrap yard, K-1064 surplus equipment and machinery, 7,000 PCB-contaminated drums, 12,000 tons of metal from the Y-l2 scrap yard, and 1,000 metal pallets. In addition, the Center of Excellence is developing a toolbox for project teams that will contain a number of specific tools to facilitate metals recycle. This Internet-based toolbox will include primers, computer programs, and case studies designed to help sites to perform life cycle analysis, perform ALARA (As Low As is Reasonably Achievable) analysis for radiation exposures, provide pollution prevention information and …

The Mixed Waste Management Facility (MWMF) is a national demonstration test bed that will be used to evaluate, at pilot scale, emerging technologies for the effective treatment of low-level radioactive, organic mixed wastes. The treatment technologies will be selected from candidates of advanced processes that have been sufficiently demonstrated in laboratory and bench-scale tests, and most closely meet suitable criteria for demonstration. The primary and initial goal will be to demonstrate technologies that have the potential to effectively treat a selection of organic-based mixed waste streams, currently in storage within the DOE, that list incineration as the best demonstrated available technology (BDAT). In future operations, the facility may also be used to demonstrate technology that addresses a broader range of government, university, medical, and industry needs. The primary objective of the MWMF is to demonstrate integrated mixed-waste processing technologies. While primary treatment processes are an essential component of integrated treatment trains, they are only a part of a fully integrated demonstration.

One of the drawbacks of standard volume rendering techniques is that is it often difficult to comprehend the three-dimensional structure of the volume from a single frame; this is especially true in cases where there is no solid surface. Generally, several frames must be generated and viewed sequentially, using motion parallax to relay depth. Another option is to generate a single spectroscopic pair, resulting in clear and unambiguous depth information in both static and moving images. Methods have been developed which take advantage of the coherence between the two halves of a stereo pair for polygon rendering and ray-tracing, generating the second half of the pair in significantly less time than that required to completely render a single image. This paper reports the results of implementing these techniques with parallel ray-traced volume rendering. In tests with different data types, the time savings is in the range of 70--80%.

The commitment by Westinghouse Savannah River Company (WSRC) to bring safety analysis and risk management codes into compliance with national and sitewide quality assurance requirements necessitated a systematic, structured approach. As a part of this effort, WSRC, in cooperation with the Westinghouse Hanford Company, has developed and implemented a certification process for the development and control of computer software. Safety analysis and risk management computer codes pertinent to reactor analyses were selected for inclusion in the certification process. As a first step, documented plans were developed for implementing verification and validation of the codes, and establishing configuration control. User qualification guidelines were determined. The plans were followed with an extensive assessment of the codes with respect to certification status. Detailed schedules and work plans were thus determined for completing certification of the codes considered. Although the software certification process discussed is specific to the application described, it is sufficiently general to provide useful insights and guidance for certification of other software.

A program is now underway to develop commercial power conversion systems that use parabolic dish mirrors in conjunction with Stirling engines to convert solar energy to electric power. In early prototypes, the solar concentrator focused light directly on the heater tubes of the Stirling engine. Liquid-metal heat-pipes are now being developed to transfer energy from the focus of the solar concentrator to the heater tubes of the engine. The dome-shaped heat-pipe receivers are approximately one-half meters in diameter and up to 77-kW of concentrated solar energy is delivered to the absorber surface. Over the past several years, Sandia National Laboratories, through the sponsorship of the Department of Energy, has conducted a major program to explore receiver designs and identify suitable wick materials. A high-flux bench-scale system has been developed to test candidate wick designs, and full-scale systems have been tested on an 11-meter test-bed solar concentrator. Procedures have also been developed in this program to measure the properties of wick materials, and an extensive data-base on wick materials for high temperature heat pipes has been developed. This paper provides an overview of the receiver development program and results from some of the many heat-pipe tests.

We present model-independent measurements of the vertical trajectory jitter of the positron beam in the Stanford Linear Collider (SLC) linac and discuss the results of studies aimed at isolating its source.

The Stanford Linear collider was designed to operate with round beams; horizontal and vertical emittance made equal in the damping rings. The main motivation was to facilitate the optical matching through beam lines with strong coupling elements like the solenoid spin rotator magnets and the SLC arcs. Tests in 1992 showed that ``flat`` beams with a vertical to horizontal emittance ratio of around 1/10 can be successfully delivered to the end of the linac. Techniques developed to measure and control the coupling of the SLC arcs allow these beams to be transported to the Interaction Point (IP). Before flat beams could be used for collisions with polarized electrons, a new method of rotating the electron spin orientation with vertical arc orbit bumps had to be developed. Early in the 1993 run, the SLC was switched to ``flat`` beam operation. Within a short time the peak luminosity of the previous running cycle was reached and then surpassed. The average daily luminosity is now a factor of about two higher than the best achieved last year. In the following we present an overview of the problems encountered and their solutions for different parts of the SLC.

In the design of the Next Linear Collider (NLC), multi-bunch operation is employed to improve efficiency at the cost of substantial beam loading. The RF pulse that powers the accelerator structures will be shaped to compensate for the effect of the transient loading along the bunch train. This scheme has been implemented in the Next Linear Collider Test Accelerator (NLCTA), a facility built to test the key accelerator technology of the NLC. In this paper the authors describe the compensation method, the techniques used to measure the energy variation along the bunch train, and results from tests with NLC-like beam currents.

Interest in the critical dynamics of superfluid <SUP>4</SUP> He in microgravity conditions has motivated the development of new high resolution thermometry technol- ogy for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide [Cu(NH<SUB>4</SUB>)<SUB>2</SUB>Br<SUB>4</SUB>2H<SUB>2</SUB>0) or "CAB", which undergoes a ferromagnetic phase transition at 1.8K1. HRTs made from CAB have demonstrated low drift (< 10fK/s) and a temperature resolu- tion of O.lnK. Unfortunately, paramagnetic salts such as CAB are difficult to prepare and handle, corrosive to most metals, and become dehydrated if kept, under vacuum conditions at room temperature. We have developed a magnetic thermometer using dilute magnetic alloys of Mn or Fe dissolved in a pure Pd matrix. These metallic thermometers are easy to fabricate, chemically inert, and mechanically robust. Unlike salts, they may be directly soldered to the stage to be measured. Also, the Curie temperature can be varied by changing the concentration of Fe or Mn, making them available for use in a wide temperature range. Susceptibility measurements, as well as preliminary noise and drifl measurements, show them, to have sub-nK resolution, with a drift of less than 10<SUP>-13</SUP> K/s.

This paper is a description of work-in-progress. It describes Sandia`s program to study the basic fluid mechanics of large-scale mixing in unbounded, compressible, turbulent flows, specifically, the turbulent mixing of an axisymmetric compressible helium jet in a parallel, coflowing compressible air freestream. Both jet and freestream velocities are variable over a broad range, providing a wide range mixing layer Reynolds number. Although the convective Mach number, M{sub c}, range is currently limited by the present nozzle design to values of 0.6 and below, straightforward nozzle design changes would permit a wide range of convective Mach number, to well in excess of 1.0. The use of helium allows simulation of a hot jet due to the large density difference, and also aids in obtaining optical flow visualization via schlieren due to the large density gradient in the mixing layer. The work comprises a blend of analysis, experiment, and direct numerical simulation (DNS). There the authors discuss only the analytical and experimental efforts to observe and describe the evolution of the large-scale structures. The DNS work, used to compute local two-point velocity correlation data, will be discussed elsewhere.

Single crystals of magnesium-aluminate spinel were implanted with 170 keV He{sup +} ions to fluences ranging from 1 x 10{sup 16}--1 x 10{sup 21} ions/m{sup 2} at 120 K. The effects of ion implantation were studied using optical absorption spectroscopy, Rutherford Backscattering Spectroscopy and Ion Channeling (RBS/C) and Transmission Electron Microscopy (TEM). In absorption spectra obtained from the implanted samples, growth of an F-center band at 5.3 eV was observed. At the fluence of 3 x 10{sup 20} ions/m{sup 2}, the growth of this band not only ceases but the intensity suddenly decreases. This may be due to formation of a new phase at this fluence. This is partially confirmed by the fact that beginning at this dose, a modulated absorbance becomes apparent in the absorption spectrum of spinel. This effect is caused by formation of a buried layer with refraction index lower than that of an unimplanted sample. RBS/C and TEM measurements show that spinel is not amorphized over the fluence range examined in this study. TEM microdiffraction observations show that in the damaged region the intensities of superlattice spots decrease significantly, suggesting that ion beam irradiation induces either an order-disorder phase transition or a transformation into the so-called …

As part of the Soviet-Designed Reactor Safety (SDRS) element of the International Nuclear Safety Program (INSP), the US Department of Energy (US DOE) is funding a plant safety evaluation (PSE) project for the Novovoronezh Nuclear Power Plant (NvNPP). The Novovoronezh PSE Project is a multi-faceted project with participants from sixteen different international organizations from five different countries scattered across eleven time zones. The purpose of this project is to provide a thorough Probabilistic Risk Analysis (PRA) and Deterministic Safety Analysis (DSA) for Units 3 and 4 of the NvNPP. In addition, this project provides assistance to the operation organizations in meeting their international commitments in support of safety upgrades, and their regulatory requirements for the conduct of safety analyses. Managing this project is a complex process requiring numerous management tools, constant monitoring, and effective communication skills. Employing management tools to resolve unanticipated problems one of the keys to project success. The overall scope, programmatic context, objectives, project interactions, communications, practical hindrances, and lessons learned from the challenging performance of the PSE project are summarized in this paper.

SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 10³Å and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size (~ 1 µm), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 µm. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a �blend� of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on µm-length scales, and USANS has also been used to quantify this phenomenon.

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Spattered carbon films are widely used as protective overcoats for thin film disk media. Raman spectroscopy is nondestructive and relatively rapid and is well suited for the characterization of carbon films. Specific features in the Raman spectra are empirically correlated with the rates of specific types of mechanical wear for both hydrogenated and unhydrogenated films. This observation is interpreted in terms of a random covalent network, in which the mechanical performance of the film is determined by the nature of the bonding that links sp{sup 2}-bonded domains.

Spattered carbon films are widely used as protective overcoats for thin film disk media. Raman spectroscopy is nondestructive and relatively rapid and is well suited for the characterization of carbon films. Specific features in the Raman spectra are empirically correlated with the rates of specific types of mechanical wear for both hydrogenated and unhydrogenated films. This observation is interpreted in terms of a random covalent network, in which the mechanical performance of the film is determined by the nature of the bonding that links sp{sup 2}-bonded domains.

The amount of data generated by CT scanners is enormous, making the reconstruction operation slow, especially for 3-D and limited-data scans requiring iterative algorithms. The Radon transform and its inverse, commonly used for CT image reconstruction from projections, are computationally burdensome for today's single-processor computer architectures. If the processing times for the forward and inverse Radon transforms were comparatively small, a large set of new CT algorithms would become feasible, especially those for 3-D and iterative tomographic image reconstructions. In addition to image reconstruction, a fast Radon Transform Computer'' could be naturally applied in other areas of multidimensional signal processing including 2-D power spectrum estimation, modeling of human perception, Hough transforms, image representation, synthetic aperture radar processing, and others. A high speed processor for this operation is likely to motivate new algorithms for general multidimensional signal processing using the Radon transform. In the proposed workshop paper, we will first describe interpolation schemes useful in computation of the discrete Radon transform and backprojection and compare their errors and hardware complexities. We then will evaluate through statistical means the fixed-point number system required to accept and generate 12-bit input and output data with acceptable error using the linear interpolation scheme selected. These …

We report on our program in detecting two-electron ionization using electron-electron and electron-ion coincidence measurements. The coincidence techniques have been applied to the multiphoton ionization (MPI) of xenon atoms with 0.527 {mu}m excitation. The results show that direct two electron ionization is not occurring which is in variance with an earlier report. We also present a polarization study on the MPI of helium at 0.62 {mu}m and discuss these results in context of existing models.

This paper presents an experimental/computational study of cold flow in the combustor-diffuser system of industrial gas turbines to address issues relating to flow interactions and pressure losses in the pre- and dump diffusers. The present configuration with can annular combustors differs substantially from the aircraft engines which typically use a 360 degree annular combustor. Experiments were conducted in a one-third scale, annular 360-degree model using several can combustors equispaced around the turbine axis. A 3-D computational fluid dynamics analysis employing the multidomain procedure was performed to supplement the flow measurements. The measured data correlated well with the computations. The airflow in the dump diffuser adversely affected the prediffuser flow by causing it to accelerate in the outer region at the prediffuser exit. This phenomenon referred to as the sink-effect also caused a large fraction of the flow to bypass much of the dump diffuser and go directly from the prediffuser exit to the bypass air holes on the combustor casing, thereby, rendering the dump diffuser ineffective in diffusing the flow. The dump diffuser was occupied by a large recirculation region which dissipated the flow kinetic energy. Approximately 1.2 dynamic head at the prediffuser inlet was lost in the combustor-diffuser system; …

A novel DRAM cell technology consisting of an access transistor and a bootstrapped storage capacitor with an integrated breakdown diode is proposed. This design offers considerable resistance to single event cell hits. The information change packet is shielded from an SE hit by placing the vulnerable node in a self-compensating standby state. The proposed cell is comparable in size to a conventional DRAM cell, but simulations show an improvement in critical charge of two orders of magnitude.