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Motion Planning for a Direct Metal Deposition Rapid Prototyping System (open access)

Motion Planning for a Direct Metal Deposition Rapid Prototyping System

A motion planning strategy was developed and implemented to generate motion control instructions from solid model data for controlling a robotically driven solid free-form fabrication process. The planning strategy was tested using a PUMA type robot arm integrated into a LENS{trademark} (Laser Engineered Net Shape) system. Previous systems relied on a series of x, y, and z stages, to provide a minimal coordinated motion control capability. This limited the complexity of geometries that could be constructed. With the coordinated motion provided by a robotic arm, the system can produce three dimensional parts by ''writing'' material onto any face of existing material. The motion planning strategy relied on solid model geometry evaluation and exploited robotic positioning flexibility to allow the construction of geometrically complex parts. The integration of the robotic manipulator into the LENS{trademark} system was tested by producing metal parts directly from CAD models.
Date: October 18, 1999
Creator: AMES,ARLO L.; HENSINGER,DAVID M. & KUHLMANN,JOEL L.
Object Type: Article
System: The UNT Digital Library
Study of electron and neutrino interactions (open access)

Study of electron and neutrino interactions

This is the final report for the DOE-sponsored experimental particle physics program at Virginia Tech to study the properties of the Standard Model of strong and electroweak interactions. This contract (DE-AS05-80ER10713) covers the period from August 1, 1980 to January 31, 1993. Task B of this contract, headed by Professor Alexander Abashian, is described in this final report. This program has been pursued on many fronts by the researchers-in a search for axions at SLAC, in electron-positron collisions in the AMY experiment at the TRISTAN collider in Japan, in measurements of muon decay properties in the MEGA and RHO experiments at the LAMPF accelerator, in a detailed analysis of scattering effects in the purported observation of a 17 keV neutrino at Oxford, in a search for a disoriented chiral condensate with the MiniMax experiment at Fermilab, and in an R&D program on resistive plate counters that could find use in low-cost high-quality charged particle detection at low rates.
Date: March 18, 1997
Creator: Abashian, A.
Object Type: Report
System: The UNT Digital Library
Study of electron and neutrino interactions. Final report (open access)

Study of electron and neutrino interactions. Final report

This is the final report for the DOE-sponsored experimental particle physics program at Virginia Tech to study the properties of the Standard Model of strong and electroweak interactions. This contract (DE-AS05-80ER10713) covers the period from August 1, 1980 to January 31, 1993. Task B of this contract, headed by Professor Alexander Abashian, is described in this final report. This program has been pursued on many fronts by the researchers in a search for axions at SLAC, in electron-positron collisions in the AMY experiment at the TRISTAN collider in Japan, in measurements of muon decay properties in the MEGA and RHO experiments at the LAMPF accelerator, in a detailed analysis of scattering effects in the purported observation of a 17 keV neutrino at Oxford, in a search for a disoriented chiral condensate with the MiniMax experiment at Fermilab, and in an R&D program on resistive plate counters that could find use in low-cost high-quality charged particle detection at low rates.
Date: March 18, 1997
Creator: Abashian, A.
Object Type: Report
System: The UNT Digital Library
Deuteron photodisintegration : new results from TJNAF. (open access)

Deuteron photodisintegration : new results from TJNAF.

The first measurements of the differential cross section from d({gamma},p)n up to 4.0 GeV were performed at the Thomas Jefferson National Accelerator Facility (TJNAF, formerly CEBAF). Bremsstrahlung photons from electron beam impinging on a copper radiator and a liquid deuterium target were employed for this experiment. The experiment was performed in Hall C where the photoprotons at forward angles in the center-of-mass were detected in the High Momentum Spectrometer (HMS) and photoprotons at backward angles were detected in the Short Orbit Spectrometer (SOS). The bremsstrahlung photon energy was reconstructed from the measured proton momentum and angle using the two-body kinematics. We report the cross section results at the proton center-of-mass angles of 37{degree} and 90{degree}. These results are in good agreement with previous lower energy measurements. The 90{degree} data continue to show the constituent-counting-rule behavior up to 4 GeV. The results will be compared with models based on QCD as well as those based on meson-exchange theory.
Date: November 18, 1997
Creator: Abbott, D. J.; Ahmidouch, A.; Armstrong, C. S.; Arrington, J.; Cummings, W. J.; Geesaman, D. F. et al.
Object Type: Article
System: The UNT Digital Library
[Letter from Julie Anne Abel to Harriet Laney, July 18, 1997] (open access)

[Letter from Julie Anne Abel to Harriet Laney, July 18, 1997]

A letter from Julie Abel to Harriet Laney about approving the use of the Getty Education Institute for the Arts grant funds for the North Texas Institute for Educators on the Visual Arts.
Date: July 18, 1997
Creator: Abel, Julie Anne
Object Type: Letter
System: The UNT Digital Library
[Letter from Julie Anne Abel to Phillip C. Diebel, March 18, 1997] (open access)

[Letter from Julie Anne Abel to Phillip C. Diebel, March 18, 1997]

A letter from Julie Anne Abel to Phillip C. Diebel about enclosing the final National Specialty Program grant payment to the North Texas Institute for Educators on the Visual Arts from The Getty Center for Education in the Arts. The payment is not attached to the document
Date: March 18, 1997
Creator: Abel, Julie Anne
Object Type: Letter
System: The UNT Digital Library
Metal waste forms from treatment of EBR-II spent fuel. (open access)

Metal waste forms from treatment of EBR-II spent fuel.

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.
Date: May 18, 1998
Creator: Abraham, D. P.
Object Type: Article
System: The UNT Digital Library
Stable Isotope Variations in Banded Iron Formations (open access)

Stable Isotope Variations in Banded Iron Formations

In spite of the significant amount of work already reported in the scientific literature, many aspects of the origin of Banded Iron Formations (BIF) remain enigmatic. The authors demonstrate that mineralogic microbanding in BIF is accompanied by autocorrelated isotopic microbanding of organic carbon and carbonate carbon and oxygen. They propose that these isotopic patterns formed as a result of episodic mixing of waters in the depositional environment of BIF.
Date: March 18, 1991
Creator: Abrajano, T. A., Jr. & Holt, B. D.
Object Type: Report
System: The UNT Digital Library
Project W-314 DST and DCRT instrument and control systems, initial assessment (open access)

Project W-314 DST and DCRT instrument and control systems, initial assessment

This report contains an assessment of the instrument and control systems in the Double Shell Tank Farms and the 244-A DCRT. The assessment report contains data from physical inspection activities and an overall engineering assessment of the instruments and control systems in use in the Double Shell Tanks.
Date: January 18, 1996
Creator: Acree, C. D.
Object Type: Report
System: The UNT Digital Library
High efficiency shale oil recovery (open access)

High efficiency shale oil recovery

The overall project objective is to demonstrate the high efficiency of the Adams Counter-Current shale oil recovery process. The efficiency will first be demonstrated at bench-scale, in the current phase, after which the demonstration will be extended to the operation of a small pilot plant. Thus the immediate project objective is to obtain data on oil shale retorting operations in a small batch rotary kiln that will be representative of operations in the proposed continuous process pilot plant. Although an oil shale batch sample is sealed in the batch kiln from the start until the end of the run, the process conditions for the batch are the same as the conditions that an element of oil shale would encounter in a larger continuous process kiln. For example, similar conditions of heatup rate, oxidation of the residue and cool-down prevail for the element in both systems. This batch kiln is a unit constructed in a 1987 Phase I SBIR tar sand retorting project. The kiln worked fairly well in that project; however, the need for certain modifications was observed. These modifications are now underway to simplify the operation and make the data and analysis more exact. The second quarter agenda consisted …
Date: July 18, 1992
Creator: Adams, C. D.
Object Type: Report
System: The UNT Digital Library
High efficiency shale oil recovery. Second quarterly report, April 1, 1992--June 30, 1992 (open access)

High efficiency shale oil recovery. Second quarterly report, April 1, 1992--June 30, 1992

The overall project objective is to demonstrate the high efficiency of the Adams Counter-Current shale oil recovery process. The efficiency will first be demonstrated at bench-scale, in the current phase, after which the demonstration will be extended to the operation of a small pilot plant. Thus the immediate project objective is to obtain data on oil shale retorting operations in a small batch rotary kiln that will be representative of operations in the proposed continuous process pilot plant. Although an oil shale batch sample is sealed in the batch kiln from the start until the end of the run, the process conditions for the batch are the same as the conditions that an element of oil shale would encounter in a larger continuous process kiln. For example, similar conditions of heatup rate, oxidation of the residue and cool-down prevail for the element in both systems. This batch kiln is a unit constructed in a 1987 Phase I SBIR tar sand retorting project. The kiln worked fairly well in that project; however, the need for certain modifications was observed. These modifications are now underway to simplify the operation and make the data and analysis more exact. The second quarter agenda consisted …
Date: July 18, 1992
Creator: Adams, C. D.
Object Type: Report
System: The UNT Digital Library
A new transport discretization scheme for arbitrary spatial meshes in XY geometry (open access)

A new transport discretization scheme for arbitrary spatial meshes in XY geometry

We introduce a new spatial discretization scheme for transport on arbitrary spatial grids in XY geometry. Our arbitrary'' spatial grid is composed of arbitrarily-connected polygons, each of which may have an arbitrary number of sides. We begin our derivation by imposing particle balance on every corner'' of each cell (Consequently, we call our scheme the corner-balance (CB) method.) We complete the derivation by introducing simple closure formulas that relate volume-averaged unknowns to surface-averaged unknowns in each corner. We discuss the relationship of the new scheme to discontinuous finite-element methods and to multiple-balance methods. We demonstrate that on simple grids, the method reduces to very robust schemes that have been studied previously. We discuss the theoretical performance of the method in the thick diffusion limit, and provide numerical results for that limit. We present additional numerical results from simple problems that test the new scheme in other limits. Finally, we offer some concluding remarks about the method. 9 refs., 6 figs.
Date: January 18, 1991
Creator: Adams, M.L.
Object Type: Article
System: The UNT Digital Library
The Paducah Post (Paducah, Tex.), Vol. 84, No. 10, Ed. 1 Wednesday, April 18, 1990 (open access)

The Paducah Post (Paducah, Tex.), Vol. 84, No. 10, Ed. 1 Wednesday, April 18, 1990

Weekly newspaper from Paducah, Texas that includes local, state, and national news along with advertising.
Date: April 18, 1990
Creator: Adams, Patty
Object Type: Newspaper
System: The Portal to Texas History
The Paducah Post (Paducah, Tex.), Vol. 84, No. 22, Ed. 1 Wednesday, July 18, 1990 (open access)

The Paducah Post (Paducah, Tex.), Vol. 84, No. 22, Ed. 1 Wednesday, July 18, 1990

Weekly newspaper from Paducah, Texas that includes local, state, and national news along with advertising.
Date: July 18, 1990
Creator: Adams, Patty
Object Type: Newspaper
System: The Portal to Texas History
Biological monitoring program for East Fork Poplar Creek (open access)

Biological monitoring program for East Fork Poplar Creek

In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Lear et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity …
Date: April 18, 1997
Creator: Adams, S. M.; Ashwood, T. L.; Beaty, T. W.; Brandt, C. C.; Christensen, S. W.; Cicerone, D. S. et al.
Object Type: Report
System: The UNT Digital Library
Volatilization of Fission Products from Metallic Melts in the Melt-Dilute Treatment Technology Development for Al-Based DOE Spent Nuclear Fuels (open access)

Volatilization of Fission Products from Metallic Melts in the Melt-Dilute Treatment Technology Development for Al-Based DOE Spent Nuclear Fuels

The melt-dilute treatment technology is being developed to facilitate the ultimate disposition of highly enriched Al-Base DOE spent nuclear fuels in a geologic repository such as that proposed for Yucca Mountain. Currently, approximately 28 MTHM is expected to be returned to the Savannah River Site from domestic and foreign research reactors. The melt-dilute treatment technology will melt the fuel assemblies to reduce their volume and alloys them with depleted uranium to isotopically dilute the 235U concentration. The resulting alloy is cast into a form for long term geologic repository storage. Benefits accrued from the melt-dilute process include the potential for significant volume reduction; reduced criticality potential, and proliferation concerns. A critical technology element in the development of the melt-dilute process is the development of offgas system requirements. The volatilization of radioactive species during the melting stage of the process primarily constitutes the offgas in this process. Several of the species present following irradiation of a fuel assembly have been shown to be volatile or semi-volatile under reactor core melt-down conditions. Some of the key species that have previously been studied are krypton, iodine, and cesium. All of these species have been shown to volatilize during melting experiments however, the degree …
Date: November 18, 1999
Creator: Adams, T.
Object Type: Article
System: The UNT Digital Library
Fifteenth Street News (Midwest City, Okla.), Vol. 21, No. 3, Ed. 1 Friday, September 18, 1992 (open access)

Fifteenth Street News (Midwest City, Okla.), Vol. 21, No. 3, Ed. 1 Friday, September 18, 1992

Newspaper from Rose State College in Midwest City, Oklahoma that includes national, local, and campus news along with advertising.
Date: September 18, 1992
Creator: Addington, Kathy
Object Type: Newspaper
System: The Gateway to Oklahoma History
LLW Notes, Volume 10, Number 6, August/September 1995 (open access)

LLW Notes, Volume 10, Number 6, August/September 1995

Newsletter distributed to the Low-Level Radioactive Waste Forum members describing current news, policies, and legislation, as well as other information relevant to the management of low-level radioactive waste.
Date: September 18, 1995
Creator: Afton Associates, Inc.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Performance of Ultra Hard Carbon Wear Coatings on Microgears Fabricated by Liga (open access)

Performance of Ultra Hard Carbon Wear Coatings on Microgears Fabricated by Liga

Stiction and friction are of concern for the reliable, long-term application of Ni-alloy micromachines. We have found that the application of a 30-70 nm hard carbon coating produces a significant reduction in the friction coefficient and wear rate of electroformed Ni substrates in reciprocating sliding contact under simulated MEMS operating conditions. To evaluate the performance of coated components, a series of 70-pm-thick microgears ranging in diameter from 0.2 to 2.2 mm were fabricated from electroformed Ni via standard LIGA processes and fixtured on posts in preparation for the coating procedure. A pulsed vacuum- arc deposition process was used to deposit a carbon coating on the gears with the plasma incident at a shallow angle to the gears' top surface. A sample bias of -2 keV was used in order to produce a coating with relatively low stress and good adhesion while maintaining high hardness. This coating process is known to be somewhat comformal to the component surfaces. The coating uniformity, particularly in the high-aspect-ratio areas between the gear teeth, was evaluated with micro-Raman spectroscopy. It is shown that the coating can be applied uniformly on the top gear surface. Between the gear teeth the coating was the same thickness as …
Date: December 18, 1998
Creator: Ager, J. W., III; Brown, I. G.; Christenson, T. R.; Dugger, M. T.; Follstaedt, D. M.; Knapp, J. A. et al.
Object Type: Article
System: The UNT Digital Library
Report to users of ATLAS - September 1998. (open access)

Report to users of ATLAS - September 1998.

The ATLAS facility has provided a total of 5749 hours of beam for research in FY1998. The accelerator operation had a very high 93% reliability factor during that period. With the startup of Gammasphere in January, our schedule has attempted to minimize scheduled downtime and maximize beam-time for research. Our best performance so far occurred during the month of May when a total of 639 hours was provided for research. From the accelerator point-of-view, recent major highlights have included first operation of a new production configuration for our {sup 17}F beams which increased the beam current on-target to 2 x 10{sup 6} {sup 17}F ions/see. The {sup 17}F production target was moved approximately 4 meters upstream and a new superconducting solenoid was added to the system to refocus the highly divergent secondary beam. This new location also places the target upstream of a new superconducting resonator which was used to reduce the energy spread of the beam delivered to the spectrograph to less than 300 keV (FWHM). An improved, liquid nitrogen cooled, multiple gas cell has also significantly contributed to better performance.
Date: November 18, 1998
Creator: Ahmad, I. & Hofman, D.
Object Type: Report
System: The UNT Digital Library
Vitrification pilot plant experiences at Fernald, Ohio (open access)

Vitrification pilot plant experiences at Fernald, Ohio

A one metric ton/day Vitrification Pilot Plant (VITPP) at Fernald, Ohio, simulated the vitrification of radium and radon bearing silo residues using representative non-radioactive surrogates containing high concentrations of lead, sulfates, and phosphates. The vitrification process was carried out at temperatures of 1,150 to 1,350 C. The VITPP processed glass for seven months, until a breach of the melter containment vessel suspended operations. More than 70,000 pounds of surrogate glass were produced by the VITPP. Experiences, lessons learned, and path forward will be presented.
Date: July 18, 1997
Creator: Akgunduz, Nina; Gimpel, Rod F.; Paine, Donald & Pierce, Vernon H.
Object Type: Report
System: The UNT Digital Library
Chemometric Analysis of Two Dimensional Decay Data: Application to {sup 17}O NMR Relaxation Matrices (open access)

Chemometric Analysis of Two Dimensional Decay Data: Application to {sup 17}O NMR Relaxation Matrices

The use of {sup 17}O NMR spectroscopy as a tool to investigate aging in polymer systems has recently been demonstrated. Because the natural abundance of {sup 17}O is extremely low (0.037%), the use of labeled {sup 17}O{sub 2} during the oxidation of polymers produces {sup 17}O NMR spectra whose signals arise entirely from the degradation species (i.e. signals from the bulk or unaged material are not observed). This selective isotopic labeling eliminates the impact of interference from the unaged material, cause (1) above. As discussed by Alam et al. spectral overlap between different degradation species as well as errors in quantification remains a major difficulty in {sup 17}O NMR spectroscopy. As a demonstration of the DECRA and CTBSA methods, relaxation matrices obtained from {sup 17}O NMR for model alcohol systems are evaluated. The benefits and limitations of these newly developed chemometric techniques are discussed.
Date: March 18, 1999
Creator: Alam, M. K. & Alam, T. M.
Object Type: Article
System: The UNT Digital Library
Good News to Europe transcript

Good News to Europe

Lecture given Tuesday, June 18, 1996 at Abilene Christian University
Date: June 18, 1996
Creator: Albright & Curtis
Object Type: Sound
System: The Portal to Texas History
Finnigan ion trap mass spectrometer detection limits and thermal energy analyzer interface status report and present capabilities (open access)

Finnigan ion trap mass spectrometer detection limits and thermal energy analyzer interface status report and present capabilities

A new Finnigan ion trap mass spectrometer was purchased and installed at LLNL. Over a period of several months the instrument was tested under a variety of conditions utilizing a capillary gas chromatography interface which allowed separated organic compounds to be carried directly into the ion source of the mass spectrometer. This direct interface allowed maximum analytical sensitivity. A variety of critical tests were performed in order to optimize the sensitivity of the system under a variety of analysis conditions. These tests altered the critical time cycles of the ionization, ion trapping, and detection. Various carrier gas pressures were also employed in order to ascertain the overall sensitivity of the instrument. In addition we have also interfaced a thermal energy analyzer (TEA) to the gas chromatograph in order to simultaneously detect volatile nitrogen containing compounds while mass spectral data is being acquired. This is the first application at this laboratory of simultaneous ultra-trace detections while utilizing two orthogonal analytical techniques. In particular, explosive-related compound and/or residues are of interest to the general community in water, soil and gas sampler. In this paper are highlighted a few examples of the analytical power of this new GC-TEA-ITMS technology.
Date: October 18, 1990
Creator: Alcaraz, A.; Andresen, B. & Martin, W.
Object Type: Report
System: The UNT Digital Library