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Engineering development for a small-scale recirculator experiment (open access)

Engineering development for a small-scale recirculator experiment

Lawrence Livermore National Laboratory (LLNL) is evaluating the physics and technology of recirculating induction accelerators for heavy-ion inertial-fusion drivers. As part of this evaluation, the authors are building a small-scale recirculator to demonstrate the concept and to use as a test bed for the development of recirculator technologies. System designs have been completed and components are presently being designed and developed for the small-scale recirculator. This paper discusses results of the design and development activities that are presently being conducted to implement the small-scale recirculator experiments. An, overview of the system design is presented along with a discussion of the implications of this design on the mechanical and electrical hardware. The paper focuses primarily on discussions of the development and design of the half-lattice period hardware and the advanced solid-state modulator.
Date: September 4, 1995
Creator: Newton, M. A.; Deadrick, F. J.; Hanks, R. L.; Hawkins, S. A.; Holm, K. A.; Kirbie, H. C. et al.
System: The UNT Digital Library
What Oracle doesn`t tell you about CASE: An incremental approach (open access)

What Oracle doesn`t tell you about CASE: An incremental approach

Oracle CASE is a very large, complex software tool. The incremental-approach method described here helps developers break the analysis paralysis syndrome by using a group of rules of thumb to build more and better applications faster.
Date: April 4, 1995
Creator: Weinstein, Arnold M.
System: The UNT Digital Library
Observation on radiation transfer experiments using k-shell absorption spectra (open access)

Observation on radiation transfer experiments using k-shell absorption spectra

Recent laser-produced plasma experiments have relied on spectroscopic comparisons with models to infer plasma temperatures. Here, the technique is applied to study thermal radiation transfer experiments. The transmission model combines high-quality atomic data with an ionization balance obtained from systematic expansions of the grand canonical ensemble. The latter avoids the ad hoc cutoffs required in free energy minimization schemes and includes Coulomb corrections usually neglected in other models. It is shown that the improved equation of state significantly affects inferred temperatures at the higher densities expected in the heat flow experiments. Even though good agreement is obtained between the experimental and theoretical transmission spectrum, the experimental uncertainties are sufficiently large that is compromises the intended bench marking of the thermal transport models.
Date: January 4, 1995
Creator: Iglesias, C. A.; Chen, M. H.; McWilliams, D. L.; Nash, J. K. & Rogers, F. J.
System: The UNT Digital Library
Nondestructive assay of TRU waste using gamma-ray active and passive computed tomography (open access)

Nondestructive assay of TRU waste using gamma-ray active and passive computed tomography

The authors have developed an active and passive computed tomography (A and PCT) scanner for assaying radioactive waste drums. Here they describe the hardware components of their system and the software used for data acquisition, gamma-ray spectroscopy analysis, and image reconstruction. They have measured the performance of the system using ``mock`` waste drums and calibrated radioactive sources. They also describe the results of measurements using this system to assay a real TRU waste drum with relatively low Pu content. The results are compared with X-ray NDE studies of the same TRU waste drum as well as assay results from segmented gamma scanner (SGS) measurements.
Date: October 4, 1995
Creator: Roberson, G. P.; Decman, D.; Martz, H.; Keto, E. R. & Johansson, E. M.
System: The UNT Digital Library
Durabilities and Microstructures of Radioactive Glasses to Immobilize Excess Actinides and Reprocessing Wastes at SRS (open access)

Durabilities and Microstructures of Radioactive Glasses to Immobilize Excess Actinides and Reprocessing Wastes at SRS

This paper presents results of an investigation of the microstructures and durabilities of glasses for immobilization of excess Pu, Am, and Cm, and of the reprocessing wastes at Savannah River Site (SRS). The reprocessing wastes will be vitrified in the Defense Waste Processing Facility (DWPF) at SRS. Another facility at SRS will be used for the Pu, Am, and Cm glasses. In this paper results are presented for a DWPF radioactive glass containing the actual fission product-actinide waste from one the million gallon storage tanks at SRS. This waste is the first radioactive sludge that will be processed in DWPF. The actinide glasses investigated had compositions based on a commercial borosilicate glass composition. All the glasses were so radioactive that they had to be prepared remotely in shielded cells and the analyses had to be performed in gloveboxes or radiobenches. Durabilities were measured using the ASTM C-1285 standard leach test. Results for four glasses are presented. The glasses are a DWPF type glass containing Tank 51 radioactive waste, two glasses containing 15 and 13 wt.percent Pu, respectively, and a glass containing Am and Cm. The radioactive DWPF glass contained 28 wtpercent waste from SRS Tank 51 and was homogeneous. The …
Date: December 4, 1995
Creator: Bibler, N.E.
System: The UNT Digital Library
Ultrahigh carbon steel for automotive applications (open access)

Ultrahigh carbon steel for automotive applications

Ultrahigh carbon steels (UHCSs), which contain 1--2.1% carbon, have remarkable structural properties for automotive application when processed to achieve fine ferrite grains with fine spheroidized carbides. When processed for high room temperature ductility, UHCS can have good tensile ductility but significantly higher strength than current automotive high strength steels. The material can also be made superplastic at intermediate temperatures and exhibits excellent die fill capability. Furthermore, they can be made hard with high compression ductility. In wire form it is projected that UHCS can exhibit extremely high strengths (5,000 MPa) for tire cord applications. Examples of structural components that have been formed from fine-grained spheroidized UHCSs are illustrated.
Date: December 4, 1995
Creator: Lesuer, D. R.; Syn, C. K. & Sherby, O. D.
System: The UNT Digital Library
Induced magnetic-field effects in inductively coupled plasmas (open access)

Induced magnetic-field effects in inductively coupled plasmas

In inductive plasma sources, the rapid spatial decay of the electric field arising from the skin effect produces a large radio frequency (RF) magnetic field via Faraday`s law. We previously determined that this magnetic field leads to a reduction of the electron density in the skin region, as well as a reduction in the collisionless heating rate. The electron deficit leads to the formation of an electrostatic potential which pulls electrons in to restore quasineutrality. Here we calculate the electron density including both the induced and electrostatic fields. If the wave frequency is not too low, the ions respond only to the averaged fields, and hence the electrostatic field is oscillatory, predominantly at the second harmonic of the applied field. We calculate the potential required to establish a constant electron density, and compare with numerical orbit-code calculations. For times short compared to ion transit times, the quasineutral density is just the initial ion density. For timescales long enough that the ions can relax, the density profile can be found from the solution of fluid equations with an effective (ponderomotive-like) potential added. Although the time-varying electrostatic potential is an extra source of heating, the net effect of the induced magnetic and …
Date: November 4, 1995
Creator: Cohen, R.H. & Rognlien, T.D.
System: The UNT Digital Library
Determination of controlling earthquakes from probabilistic seismic hazard analysis for nuclear reactor sites (open access)

Determination of controlling earthquakes from probabilistic seismic hazard analysis for nuclear reactor sites

Recently, the US Nuclear Regulatory Commission published, for public comments, a revision to 10 CFR Part 100. The proposed regulation acknowledges that uncertainties are inherent in estimates of the Safe Shutdown Earthquake Ground Motion (SSE) and requires that these uncertainties be addressed through an appropriate analysis. One element of this evaluation is the assessment of the controlling earthquake through the probabilistic seismic hazard analysis (PSHA) and its use in determining the SSE. This paper reviews the basis for the various key choices in characterizing the controlling earthquake.
Date: April 4, 1995
Creator: Boissonnade, A.; Bernreuter, D.; Chokshi, N. & Murphy, A.
System: The UNT Digital Library
Preparation and characterization of beryllium doped organic plasma polymer coatings (open access)

Preparation and characterization of beryllium doped organic plasma polymer coatings

We report the formation of beryllium doped plasma polymerized coatings derived from a helical resonator deposition apparatus, using diethylberyllium as the organometaric source. These coatings had an appearance not unlike plain plasma polymer and were relatively stable to ambient exposure. The coatings were characterized by Inductively Coupled Plasma Mass Spectrometry and X-Ray Photoelectron Spectroscopy. Coating rates approaching 0.7 {mu}m hr{sup {minus}1} were obtained with a beryllium-to-carbon ratio of 1:1.3. There is also a significant oxygen presence in the coating as well which is attributed to oxidation upon exposure of the coating to air. The XPS data show only one peak for beryllium with the preponderance of the XPS data suggesting that the beryllium exists as BeO. Diethylberyllium was found to be inadequate as a source for beryllium doped plasma polymer, due to thermal decomposition and low vapor recovery rates.
Date: October 4, 1995
Creator: Brusasco, R.; Letts, S.; Miller, P.; Saculla, M. & Cook, R.
System: The UNT Digital Library
Non-thermal plasma techniques for abatement of volatile organic compounds and nitrogen oxides (open access)

Non-thermal plasma techniques for abatement of volatile organic compounds and nitrogen oxides

Non-thermal plasma processing is an emerging technology for the abatement of volatile organic compounds (VOCs) and nitrogen oxides (NO{sub x}) in atmospheric-pressure air streams. Either electrical discharge or electron beam methods can produce these plasmas. Each of these methods can be implemented in many ways. There are many types of electrical discharge reactors, the variants depending on the electrode configuration and electrical power supply (pulsed, AC or DC). Two of the more extensively investigated types of discharge reactors are based on the pulsed corona and dielectric-barrier discharge. Recently, compact low-energy (<200 keV) electron accelerators have been developed to meet the requirements of industrial applications such as crosslinking of polymer materials, curing of solvent-free coatings, and drying of printing inks. Special materials have also been developed to make the window thin and rugged. Some of these compact electron beam sources are already commercially available and could be utilized for many pollution control applications. In this paper we will present a comparative assessment of various nonthermal plasma reactors. The thrust of our work has been two-fold: (1) to understand the scalability of various non-thermal plasma reactors by focusing on the energy efficiency of the electron and chemical kinetics, and (2) to identify …
Date: December 4, 1995
Creator: Penetrante, B. M.; Hsiao, M. C.; Bardsley, J. N.; Merritt, B. T.; Vogtlin, G. E.; Wallman, P. H. et al.
System: The UNT Digital Library
Micro-electro-mechanical systems projects at Lawrence Livermore National Laboratory (open access)

Micro-electro-mechanical systems projects at Lawrence Livermore National Laboratory

The Lawrence Livermore National Laboratory (LLNL) MicroTechnology Center has developed a wide variety of special capabilities used to design, build, and test MEMS (Micro-Electro-Mechanical Systems). Our customers are both the LLNL Programs and a variety of external customers. Typical applications include: custom microstructures for scientific experiments; physical sensors; photonics; miniature tools for catheter-based surgery; and microinstruments for chemical analysis for biomedicine, environments and treaty verification. The majority of our prototype MEMS devices are fabricated with bulk silicon micromachining, but we also utilize surface micromachining capabilities.
Date: August 4, 1995
Creator: Folta, James A.
System: The UNT Digital Library