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Cloud to CAD

Description: This paper documents work performed to convert scanned range data to CAD solid model representation. The work successfully developed surface fitting algorithms for quadric surfaces (e.g. plane, cone, cylinder, and sphere), and a segmentation algorithm based entirely on surface type, rather than on a differential metric like Gaussian curvature. Extraction of all CAD-required parameters for quadric surface representation was completed. Approximate face boundaries derived from the original point cloud were constructed. Work to extrapolate surfaces, compute exact edges and solid connectivity was begun, but left incomplete due to funding reductions. The surface fitting algorithms are robust in the face of noise and degenerate surface forms.
Date: May 1, 2001
Creator: AMES,ARLO L.
Partner: UNT Libraries Government Documents Department
open access

OPTIMUM ENERGY ABSORPTION OF A SHORT-PULSE LASER IN A DOPED DIELECTRIC SLAB

Description: A model is used to calculate energy absorption efficiency when a short-pulse laser impinges on a dielectric slab doped with an impurity for which the electrons have a resonant line at the laser wavelength. The amount of the energy resonant absorption is due to the overlapping between laser spectrum and resonance spectrum. The energy absorption efficiency can be maximized for a certain degree of doping concentration (at a given pulselength) and also for a certain pulselength (at a given doping concentration). For a modest amount of impurity, the resonant absorption may increase the fraction of energy absorption up to tens of percent of laser energy at 100s optical cycles when the laser wavelength is tuned within 1% of the resonant line. Dimensionless parameters are constructed so that the scaling to various parameters: laser wavelength, laser pulselength, dielectric constant, slab thickness, impurity concentration, resonant linewidth, and separation between the laser wavelength and the line resonance, could easily be obtained.
Date: May 1, 2001
Creator: ANG, L.
Partner: UNT Libraries Government Documents Department
open access

The CLAS Forward Electromagnetic Calorimeter

Description: The CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab utilizes six iron-free superconducting coils to provide an approximately toroidal magnetic field. The six sectors are instrumented individually to form six independent spectrometers. The forward region (8deg < (theta) < 45deg) of each sector is equipped with a lead-scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy and position resolution, the EC is used to provide the primary electron trigger for CLAS. It is also used to reject pions, reconstruct pi-0 and eta decays and detect neutrons, This paper treats the design, construction and performance of the calorimeter.
Date: May 1, 2001
Creator: Amarian, M.; Asryan, Geram; Beard, Kevin; Brooks, Will; Burkert, Volker; Carstens, Tom et al.
Partner: UNT Libraries Government Documents Department
open access

Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

Description: This report documents experiments and analyses that have been done at the Idaho National Engineering and Environmental Laboratory (INEEL) to measure the steam chemical reactivity of two types of carbon fiber composites, NS31 and NB31, proposed for use at the divertor strike points in an ITER-like tokamak. These materials are 3D CFCs constituted by a NOVOLTEX preform and densified by pyrocarbon infiltration and heat treatment. NS31 differs from NB31 in that the final infiltration was done with liquid silicon to reduce the porosity and enhance the thermal conductivity of the CFC. Our approach in this work was twofold: (1) physical characterization measurements of the specimens and (2) measurements of the chemical reactivity of specimens exposed to steam.
Date: May 1, 2001
Creator: Anderl, Robert Andrew; Pawelko, Robert James & Smolik, Galen Richard
Partner: UNT Libraries Government Documents Department
open access

MINIMIZING WASTE AND COST IN DISPOSITION OF LEGACY RESIDUES

Description: Research is being conducted at the Los Alamos National Laboratory (LANL) which is directed toward development of a quantitative basis for disposition of actinide-bearing process residues (both legacy residues and residues generated from ongoing programmatic operations). This research is focused in two directions: (1) identifying minimum negative consequence (waste, dose, cost) dispositions working within regulatory safeguards termination criteria, and (2) evaluating logistics/consequences of across-the-board residue discards such as authorized at Rocky Flats under a safeguards termination variance. The first approach emphasizes Laboratory commitments to environmental stewardship, worker safety, and fiscal responsibility. This approach has been described as the Plutonium Disposition Methodology (PDM) in deference to direction provided by DOE Albuquerque. The second approach is born of the need to expedite removal of residues from storage for programmatic and reasons and residue storage safety concerns. Any disposition path selected must preserve the legal distinction between residues as Special Nuclear Material (SNM) and discardable materials as waste in order to insure the continuing viability of Laboratory plutonium processing facilities for national security operations.
Date: May 1, 2001
Creator: BALKEY, J. & ROBINSON, M.
Partner: UNT Libraries Government Documents Department
open access

UTILIZATION OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY FIRE DYNAMICS SIMULATION COMPUTER MODEL

Description: The objective of this report is to provide a methodology for utilization of the NIST FDS code to evaluate the effects of radiant and convective heating from single and multiple fire sources, on heat sensitive targets as Special Nuclear Materials (SNM), and High Explosives (HE). The presentation will demonstrate practical applications of the FDS computer program in fire hazards analysis, and illustrate the advantages over hand calculations for radiant heat and convective transfer and fire progression. The ''visualization'' of radiant and convective heat effects will be demonstrated as a tool for supporting conclusions of fire hazards analysis and TSR development.
Date: May 1, 2001
Creator: BARTLEIN, L.
Partner: UNT Libraries Government Documents Department
open access

A PERSPECTIVE ON RELIABILITY: PROBABILITY THEORY AND BEYOND

Description: Reliability assessment in the coming era is inclined to be characterized by a difficult dilemma. On the one hand units and systems will be required to be ultra reliable; on the other hand, it may not be possible to subject them to a full-scale testing. A case in point occurs where testing is limited is one-of-a-kind complex systems, such as space exploration vehicles or where severe testing constraints are imposed such as full scale testing of strategic nuclear weapons prohibited by test ban treaties and international agreements. Decision makers also require reliability assessments for problems with terabytes of data, such as from complex simulations of system performance. Quantitative measures of reliability and their associated uncertainties will remain integral to system monitoring and tactical decision making. The challenge is to derive these defensible measures in light of these dilemmas. Because reliability is usually defined as a probability that the system performs to its required specification, probability enters into the heart of these dilemmas, both philosophically and practically. This paper provides an overview of the several interpretations of probability as they relate to reliability and to the uncertainties involved. The philosophical issues pertain to the interpretation and the quantification of reliability. For example, how must we interpret a number like 10{sup {minus}9}, for the failure rate of an airplane flight or an electrical power plant? Such numbers are common, particularly in the context of safety. Does it mean one failure in 10{sup 9} identical, or almost identical, trials? Are identical trials physically possible, let alone the fact that 10{sup 9} trials can take generations to perform? How can we make precise the notion of almost identical trials? If the trials are truly identical, then all of them must produce the same outcome and so the reliability must be either one or zero. …
Date: May 1, 2001
Creator: BOOKER, J. M. & SINGPURWALLA, N. D.
Partner: UNT Libraries Government Documents Department
open access

DEVELOPMENT AND IMPLEMENTATION OF THE LOS ALAMOS NATIONAL LABORATORY INDEPENDENT SAR REVIEW PROCESS.

Description: Contractor independent review of contractor prepared safety documents has ceased as a requirement under DOE orders. However, a recent study to determine root causes of the poor quality and extremely long approval times for Los Alamos National Laboratory nuclear safety document has identified such a review as a crucial step in ensuring quality. LANL has teamed with the DOE Field Office to reinstate an independent review process modeled after DOE-STD-1104. A review guide has been prepared predicated on the content of DOE-STD-3009. Discipline has been enforced to ensure that comments reflect important issues and that resolution of the comment is possible. Safety management at both LANL and DOE have embraced this concept. This process has been exercised and has resulted in improvements in safety analysis quality and a degree of uniformity between DOE and LANL reviews.
Date: May 1, 2001
Creator: BUECK, J. & MARTH, T.
Partner: UNT Libraries Government Documents Department
open access

Collisionless relaxation in beam-plasma systems

Description: This thesis reports the results from the theoretical investigations, both numerical and analytical, of collisionless relaxation phenomena in beam-plasma systems. Many results of this work can also be applied to other lossless systems of plasma physics, beam physics and astrophysics. Different aspects of the physics of collisionless relaxation and its modeling are addressed. A new theoretical framework, named Coupled Moment Equations (CME), is derived and used in numerical and analytical studies of the relaxation of second order moments such as beam size and emittance oscillations. This technique extends the well-known envelope equation formalism, and it can be applied to general systems with nonlinear forces. It is based on a systematic moment expansion of the Vlasov equation. In contrast to the envelope equation, which is derived assuming constant rms beam emittance, the CME model allows the emittance to vary through coupling to higher order moments. The CME model is implemented in slab geometry in the absence of return currents. The CME simulation yields rms beam sizes, velocity spreads and emittances that are in good agreement with particle-in-cell (PIC) simulations for a wide range of system parameters. The mechanism of relaxation is also considered within the framework of the CME system. It is discovered that the rapid relaxation or beam size oscillations can be attributed to a resonant coupling between different modes of the system. A simple analytical estimate of the relaxation time is developed. The final state of the system reached after the relaxation is complete is investigated. New and accurate analytical results for the second order moments in the phase-mixed state are obtained. Unlike previous results, these connect the final values of the second order moments with the initial beam mismatch. These analytical estimates are in good agreement with the CME model and PIC simulations. Predictions for the final density …
Date: May 1, 2001
Creator: Backhaus, Ekaterina Yu.
Partner: UNT Libraries Government Documents Department
open access

ADVANCED FLUE GAS CONDITIONING AS A RETROFIT UPGRADE TO ENHANCE PM COLLECTION FROM COAL-FIRED ELECTRIC UTILITY BOILERS

Description: The U.S. Department of Energy and ADA Environmental Solutions has begun a project to develop commercial flue gas conditioning additives. The objective is to develop conditioning agents that can help improve particulate control performance of smaller or under-sized electrostatic precipitators on utility coal-fired boilers. The new chemicals will be used to control both the electrical resistivity and the adhesion or cohesivity of the flyash. There is a need to provide cost-effective and safer alternatives to traditional flue gas conditioning with SO{sub 3} and ammonia. During the fourth reporting quarter, laboratory-screening tests of more than 20 potential additive formulations were completed. For these tests, the electrostatic tensiometer method was used for determination of flyash cohesivity. Resistivity was measured for each screening test with a new multi-cell laboratory flyash resistivity furnace constructed for this project. An initial field trial of three additive formulations was also conducted at the City of Ames, Iowa Municipal Power Plant.
Date: May 1, 2001
Creator: Baldrey, Kenneth E.
Partner: UNT Libraries Government Documents Department
open access

ADVANCED FLUE GAS CONDITIONING AS A RETROFIT UPGRADE TO ENHANCE PM COLLECTION FROM COAL-FIRED ELECTRIC UTILITY BOILERS

Description: The U.S. Department of Energy and ADA Environmental Solutions has begun a project to develop commercial flue gas conditioning additives. The objective is to develop conditioning agents that can help improve particulate control performance of smaller or under-sized electrostatic precipitators on utility coal-fired boilers. The new chemicals will be used to control both the electrical resistivity and the adhesion or cohesivity of the flyash. There is a need to provide cost-effective and safer alternatives to traditional flue gas conditioning with SO{sub 3} and ammonia. During this reporting quarter, further laboratory-screening tests of additive formulations were completed. For these tests, the electrostatic tensiometer method was used for determination of flyash cohesivity. Resistivity was measured for each screening test with a multi-cell laboratory flyash resistivity furnace constructed for this project. Also during this quarter chemical formulation testing was undertaken to identify stable and compatible resistivity/cohesivity liquid products.
Date: May 1, 2001
Creator: Baldrey, Kenneth E.
Partner: UNT Libraries Government Documents Department
open access

Effective field theory for the small-x evolution

Description: The small-x behavior of structure functions in the saturation region is determined by the non-linear generalization of the BFKL equation. I suggest the effective field theory for the small-x evolution which solves formally this equation. The result is the 2+1 functional integral for the structure functions at small x.
Date: May 1, 2001
Creator: Balitsky, Ian
Partner: UNT Libraries Government Documents Department
open access

Conbined noble gas and stable isotope constraints on nitrogen gas sources within sedimentary basins. Final report for period 15 March 1996 - 14 March 1999 extended to 14 March 2000

Description: Nitrogen is one of the major non-hydrocarbon gases found in natural gas reservoirs. The objective of this work was to combine the information available from both noble gas and stable isotope systematics to understand the origin of nitrogen and related gas sources, transport behavior, and mass balance within natural gas reservoirs and sedimentary basin systems. The goals achieved are summarized under the following headings: Noble gas and stable isotopes in nitrogen-rich natural gases; Noble gases in groundwater; and Characterization of magmatic and crustal noble gas input into basin systems. Lists of publications and presentations are included.
Date: May 1, 2001
Creator: Ballentine, C.J.; Halliday, Alexander N. & Lollar, B. Sherwood
Partner: UNT Libraries Government Documents Department
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Oxygen Transport Ceramic Membranes Quarterly Report

Description: The mechanical properties of model systems were analyzed. A reasonably accurate finite element model was implemented and a rational metric to predict the strength of ceramic/metal concentrical joints was developed. The mode of failure of the ceramic/metal joints was determined and the importance of the mechanical properties of the braze material was assessed. Thermal cycling experiments were performed on the model systems and the results were discussed. Additionally, experiments using the concept of placing diffusion barriers on the ceramic surface to limit the extent of the reaction with the braze were performed. It was also observed that the nature and morphology of the reaction zone depends greatly on the nature of the perovskite structure being used. From the experiments, it is observed that the presence of Cr in the Fe-occupied sites decreases the tendency of Fe to segregate and to precipitate out of the lattice. In these new experiments, Ni was observed to play a major role in the decomposition of the ceramic substrate.
Date: May 1, 2001
Creator: Bandopadhyay, Sukumar & Nagabhushana, Nagendra
Partner: UNT Libraries Government Documents Department
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Lessons Learned from JTA Tester Safety Studies

Description: EP401575, Issue C, calls out a requirement to perform safety studies for testers that are used to accept Joint Test Assembly (JTA) product at Pantex (Reference 1). The underlying motivation is to ensure that personnel hazards due to inadvertent initiation of electro-explosive devices (EEDs) during JTA testing are understood and minimized. Studies have been performed on the B61-7/11 JTA, B61-3/4/10 JTA, B83 JTA, and W76 Type 2F testers at Pantex (References 2-5). Each of these studies includes an examination of the relevant Pantex tester as well as the instrumentation and War Reserve (WR) hardware. In performing these analyses, several themes have emerged that could be useful for the Phase 6.3 design efforts for the weapons, the associated instrumentation, and the JTA testers. This report summarizes the lessons learned from these studies. Note that in some cases, the recommendations provided below to enhance safety during JTA testing operations (e.g., adding isolation resistors in the monitoring lines) may result in a reliability degradation or other surety impact. Thus it is important to consider these lessons learned in the context of the overall design and to make tradeoffs in light of the integrated surety objectives. The lessons learned are listed in five different categories, summarized as: (1) Instrumentation considerations; (2) WR design considerations; (3) Tester considerations; (4) Administrative procedures during JTA assembly; and (5) Administrative procedures prior to and during JTA testing. The first three focus on minimizing the probability of inadvertent application of power to EED initiation lines due to component, connector, and assembly failures. The last two describe procedural steps that can be taken at Pantex to either minimize the risk (e.g., by ensuring that tester power supplies cannot supply excessive power to the unit under test) or to mitigate the consequences of unexpected EED initiation (e.g., by instructing test operators …
Date: May 1, 2001
Creator: Bierbaum, R. L.
Partner: UNT Libraries Government Documents Department
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