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Plasma gate switch experiment on Pegasus II
The plasma gate switch is a novel technique for producing a long conduction time vacuum opening switch. The switch consists of an aluminum foil which connects the cathode to the anode in a coaxial geometry. The foil is designed so that the maximum axial acceleration is in the center of the foil and that at the appropriate time, the center opens up and magnetic flux is carried down the gun to the load region. The switch is designed to minimize the amount of mass transported into the load region. We have completed the first experimental test of this design and present results from the test. These results indicate there were some asymmetry problems in the construction of the switch but that otherwise the switch performed as expected.
Date:
September 1995
Creator:
Wysocki, F. J.; Benage, J. F., Jr. & Shlachter, J. S.
Object Type:
Article
System:
The UNT Digital Library
Neutron diffraction study of NiTi during compressive deformation and after shape-memory recovery
Neutron diffraction measurements of internal elastic strains and texture were performed during compressive deformation of martensitic NiTi deforming by twinning. Rietveld refinement of the diffraction spectrum was performed in order to obtain lattice parameter variations and preferred orientation of martensitic variants. The elastic internal strains, are proportional to the externally applied stress but strongly dependent on crystallographic orientation. Plastic deformation by matrix twinning is consistent with type I (1-1-1) twinning, whereby (100) and (011) planes tend to align perpendicular and parallel to the stress axis, respectively. The preferred orientation ratio r according to the model by March and Dollase is proportional to the macroscopic plastic strain for (100) and (011) planes for loading, unloading and shape-memory recovery. To the best of our knowledge, this is the first in situ bulk measurement of reversible twinning in NiTi. Finally, shape-memory recovery results in a marked change of NiTi cell parameters.
Date:
September 1995
Creator:
Dunand, D. C.; Mari, D.; Bourke, Mark A. M. & Goldstone, Joyce A.
Object Type:
Report
System:
The UNT Digital Library
Network improvement problems
The authors study budget constrained optimal network improvement problems. Such problems aim at finding optimal strategies for improving a network under some cost measure subject to certain budget constraints. As an example, consider the following prototypical problem: Let G = (V, E) be an undirected graph with two cost values L(e) and C(e) associated with each edge e, where L(e) denotes the length of e and C(e) denotes the cost of reducing the length of e by a unit amount. A reduction strategy specifies for each edge e, the amount by which L(e) is to be reduced. For a given budget B, the goal is to find a reduction strategy such that the total cost of reduction is at most B and the minimum cost tree (with respect to some measure M) under the modified L costs is the best over all possible reduction strategies which obey the budget constraint. Typical measures M for a tree are the total weight and the diameter. They provide both hardness and approximation results for the two measures M mentioned above. For the problem of minimizing the total weight of a spacing tree, they provide an algorithm that, for any fixed {gamma},{var_epsilon} > 0, …
Date:
September 1, 1995
Creator:
Krumke, S. O.; Noltemeier, H.; Drangmeister, K. U.; Marathe, M. V. & Ravi, S. S.
Object Type:
Article
System:
The UNT Digital Library
National low-level waste management program radionuclide report series, Volume 14: Americium-241
This report, Volume 14 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of americium-241 ({sup 241}Am). This report also includes discussions about waste types and forms in which {sup 241}Am can be found and {sup 241}Am behavior in the environment and in the human body.
Date:
September 1, 1995
Creator:
Winberg, M. R. & Garcia, R. S.
Object Type:
Report
System:
The UNT Digital Library
CP Violation in B Decays at the Tevatron
Between 1992 to 1996, the CDF and D0 detectors each collected data samples exceeding 100 pb{sup {minus}1} of p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. These data sets led to a large number of precision measurements of the properties of B hadrons including lifetimes, masses, neutral B meson flavor oscillations, and relative branching fractions, and to the discovery of the B{sub 0} meson. Perhaps the most exciting result was the first look at the CP violation parameter sin ({vert_bar}2{beta}){vert_bar} using the world's largest sample of fully reconstructed B{sup 0}/{bar B}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0} decays. A summary of this result is presented here. In the year 2000, the Tevatron will recommence p{bar p} collisions with an over order of magnitude expected increased in integrated luminosity (1 fb{sup {minus}1} per year). The CDF and D0 detectors will have undergone substantial upgrades, particularly in the tracking detectors and the triggers. With these enhancements, the Tevatron B physics program includes precision measurements of sin(2{beta}) and B{sub s}{sup 0} flavor oscillations, as well as studies of rare B decays that are sensitive to new physics. The studies of B{sub s}{sup 0} mesons will be particularly interesting as this …
Date:
September 17, 1999
Creator:
Kroll, I. Joseph
Object Type:
Article
System:
The UNT Digital Library
Nuclear properties for astrophysical applications
We tabulate the ground-state odd-proton and odd-neutron spins, proton and neutron pairing gaps, binding energies, neuton separation energies, quantities related to {beta}-delayed one, two and three neutron emission probabilities, {beta}-decay Q values and half-lives with respect to Gamow-Teller decay, proton separation energies, and {alpha}-decay Q values and half-lives. The starting point of the calculations is a calculation of nuclear ground-states and (information based on the finite-range droplet model and the folded-Yukawa single-particle model published in a previous issue of ATOMIC DATA AND NUCLEAR DATA TABLES. The {beta}-delayed neutron-emission probabilities and Gamow-Teller {beta}-decay rates are obtained from a QRPA model that uses single-particle levels and wave-functions at the calculated nuclear ground-state shape as the starting point.
Date:
September 23, 1994
Creator:
Moeller, P.; Nix, J. R. & Kratz, K. L.
Object Type:
Report
System:
The UNT Digital Library
Efficient separations and processing crosscutting program: Develop and test sorbents
This report summarizes work performed during FY 1995 under the task {open_quotes}Develop and Test Sorbents,{close_quotes} the purpose of which is to develop high-capacity, selective solid extractants to recover cesium, strontium, and technetium from nuclear wastes. This work is being done for the Efficient Separations and Processing Crosscutting Program (ESP), operated by the U.S. Department of Energy`s Office of Environmental Management`s Office of Technology Development. The task is under the direction of staff at Pacific Northwest Laboratory (PNL) with key participation from industrial and university staff at 3M, St. Paul, Minnesota; IBC Advanced Technologies, Inc., American Forks, Utah; AlliedSignal, Inc., Des Plaines, Illinois, and Texas A&M University, College Station, Texas. 3M and IBC are responsible for ligand and membrane technology development; AlliedSignal and Texas A&M are developing sodium titanate powders; and PNL is testing the materials developed by the industry/university team members. Major accomplishments for FY 1995 are summarized in this report.
Date:
September 1, 1995
Creator:
Bray, L.A.
Object Type:
Report
System:
The UNT Digital Library
Solid Waste Operations Complex W-113, Detail Design Report (Title II). Volume 2: Solid waste retrieval facilities -- Phase 1, detail design drawings
The Solid Waste Retrieval Facility--Phase 1 (Project W113) will provide the infrastructure and the facility required to retrieve from Trench 04, Burial ground 4C, contact handled (CH) drums and boxes at a rate that supports all retrieved TRU waste batching, treatment, storage, and disposal plans. This includes (1) operations related equipment and facilities, viz., a weather enclosure for the trench, retrieval equipment, weighing, venting, obtaining gas samples, overpacking, NDE, NDA, shipment of waste and (2) operations support related facilities, viz., a general office building, a retrieval staff change facility, and infrastructure upgrades such as supply and routing of water, sewer, electrical power, fire protection, roads, and telecommunication. Title I design for the operations related equipment and facilities was performed by Raytheon/BNFL, and that for the operations support related facilities including infrastructure upgrade was performed by KEH. These two scopes were combined into an integrated W113 Title II scope that was performed by Raytheon/BNFL. Volume 2 provides the complete set of the Detail Design drawings along with a listing of the drawings. Once approved by WHC, these drawings will be issued and baselined for the Title 3 construction effort.
Date:
September 1, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
The Effect of Shock Stress and Field Strength on Shock-Induced Depoling of Normally Poled PZT 95/5
Shock-induced depoling of the ferroelectric ceramic PZT 95/5 is utilized in a number of pulsed power devices. Several experimental and theoretical efforts are in progress in order to improve numerical simulations of these devices. In this study we have examined the shock response of normally poled PZT 95/5 under uniaxial strain conditions. On each experiment the current produced in an external circuit and the transmitted waveform at a window interface were recorded. The peak electrical field generated within the PZT sample was varied through the choice of external circuit resistance. Shock pressures were varied from 0.6 to 4.6 GPa, and peak electrical fields were varied from 0.2 to 37 kV/cm. For a 2.4 GPa shock and the lowest peak field, a nearly constant current governed simply by the remanent polarization and the shock velocity was recorded. Both decreasing the shock pressure and increasing the electrical field resulted in reduced current generation, indicating a retardation of the depoling kinetics.
Date:
September 1, 1999
Creator:
CHHABILDAS,LALIT C.; FURNISH,MICHAEL D.; MONTGOMERY,STEPHEN T. & SETCHELL,ROBERT E.
Object Type:
Article
System:
The UNT Digital Library
PVUSA procurement, acceptance, and rating practices for photovoltaic power plants
This report is one in a series of PVUSA reports on PVUSA experiences and lessons learned at the demonstration sites in Davis and Kerman, California, and from participating utility host sites. During the course of approximately 7 years (1988--1994), 10 PV systems have been installed ranging from 20 kW to 500 kW. Six 20-kW emerging module technology arrays, five on universal project-provided structures and one turnkey concentrator, and four turnkey utility-scale systems (200 to 500 kW) were installed. PVUSA took a very proactive approach in the procurement of these systems. In the absence of established procurement documents, the project team developed a comprehensive set of technical and commercial documents. These have been updated with each successive procurement. Working closely with vendors after the award in a two-way exchange provided designs better suited for utility applications. This report discusses the PVUSA procurement process through testing and acceptance, and rating of PV turnkey systems. Special emphasis is placed on the acceptance testing and rating methodology which completes the procurement process by verifying that PV systems meet contract requirements. Lessons learned and recommendations are provided based on PVUSA experience.
Date:
September 1, 1995
Creator:
Dows, R. N. & Gough, E. J.
Object Type:
Report
System:
The UNT Digital Library
Crystal field in the heavy fermion compound CeAl{sub 3}.
Although the crystal field has a strong influence on the heavy fermion properties of CeAl{sub 3}, the parameters of the crystal field Hamiltonian have not been established. We present the results of an analysis of inelastic neutron scattering data on CeAl{sub 3} to resolve this issue. By combining the neutron scattering results with measurements of the single crystal magnetic susceptibility, we have obtained an unambiguous set of crystal field parameters in CeAl{sub 3}: B{sub 2}{sup 0} = (5.8 {+-} 0.2) x 10{sup {minus}2} meV and B{sub 4}{sup 0} = (2.3 {+-} 0.1) x 10{sup {minus}2} meV. The corresponding level scheme of the ground multiplet of the Ce{sup 3+} ion is characterized by a {Lambda}{sub 9} {vert_bar} {+-} 3/2> ground state doublet and two close-lying excited doublets {Lambda}{sub 8} {vert_bar} {+-} 5/2> and {Lambda}{sub 7} {vert_bar} {+-} 1/2> at an energy of {approximately} 6.4 meV at 20 K. A comparison of the crystal field parameters along the RAl{sub 3} (R = Ce, Pr and Nd) series of isostructural compounds shows that in CeAl{sub 3}, A{sub 2}{sup 0} <r{sup 2}> is an order of magnitude larger, and A{sub 4}{sup 0} <R{sup 4}> is three times larger, than in PrAl{sub 3} and NdAl{sub …
Date:
September 11, 1998
Creator:
Goremychkin, E. A.
Object Type:
Article
System:
The UNT Digital Library
Research on oil recovery mechanisms in heavy oil reservoirs. [Quarterly] report, April--June 30, 1995
The goal of the Stanford University Petroleum Research Institute is to conduct research directed toward increasing the recovery of heavy oils. Presently, SUPRI is working in five main directions: (1) Flow properties studies -- To assess the influence of different reservoir conditions (temperature and pressure) on the absolute and relative permeability to oil and water and on capillary pressure. (2) In-situ combustion -- To evaluate the effect of different reservoir parameters on the in-situ combustion process. Ibis project includes the study of the kinetics of the reactions. (3) Steam with additives - To develop and understand the mechanisms of the process using commercially available surfactants for reduction of gravity override and channeling of steam. (4) Formation evaluation -- To develop and improve techniques of formation evaluation such as tracer tests and pressure transient tests. (5) Field support services -- To provide technical support for design and monitoring of DOE sponsored or industry initiated field projects. Accomplishments for this quarter are briefly described for each study.
Date:
September 1, 1995
Creator:
Brigham, W.E.
Object Type:
Report
System:
The UNT Digital Library
1998 Environmental Monitoring Program Report for the Idaho National Engineering and Environmental Laboratory
This report describes the calendar year 1998 compliance monitoring and environmental surveillance activities of the Lockheed Martin Idaho Technologies Company Environmental Monitoring Program performed at the Idaho National Engineering and Environmental Laboratory. This report includes results of sampling performed by the Drinking Water, Effluent, Storm Water, Groundwater Monitoring, and Environmental Surveillance Programs. This report compares the 1998 results to program-specific regulatory guidelines and past data to evaluate trends. The primary purposes of the monitoring and surveillance activities are to evaluate environmental conditions, to provide and interpret data, to verify compliance with applicable regulations or standards, and to ensure protection of public health and the environment. Surveillance of environmental media did not identify any previously unknown environmental problems or trends, which would indicate a loss of control or unplanned releases from facility operations. The INEEL complied with permits and applicable regulations, with the exception of nitrogen samples in a disposal pond effluent stream and iron and total coliform bacteria in groundwater downgradient from one disposal pond. Data collected by the Environmental Monitoring Program demonstrate that the public health and environment were protected.
Date:
September 1, 1999
Creator:
Street, L. V.
Object Type:
Report
System:
The UNT Digital Library
Degradation of a N06690 borescope in a radioactive waste/glass melter system
Radioactive liquid waste from nuclear materials production processes wi11 be vitrified in the Defense Waste Process Facility (DWPF) melter. The melter borescope outer housing, fabricated from N06690, was severely degraded by the combined effects of corrosion and oxidation after only five months of non radioactive operation. The melter was idled and not being fed over 85% of the time during the cold run operations. The borescope was designed to perform in an oxygen rich, chloride containing environment with temperatures approaching 900{degree}C (1650{degree}F). The housing was designed for a minimum of two years of continuous service in the DWPF melter. Air and steam were purged through the borescope and swept over the optics assembly to keep molten glass and volatile gases from depositing on the lens cover. Upon exiting the borescope the air passes through a N06690 orifice and enters the melter. Severe oxidation was observed around the orifice. Extensive material loss was also observed on the side of the outer housing which protrudes through the dome of the melter. Redesign of the borescope is currently underway and will include a new set of optics that will allow the size of the orifice to be significantly decreased, thus reducing the amount …
Date:
September 1995
Creator:
Imrich, K. J.
Object Type:
Article
System:
The UNT Digital Library
A molecular architectural approach to second-order nonlinear optical materials
Design and synthesis of a family of calix[4]arene-based nonlinear optical (NLO) chromophores are discussed. The calixarene chromophores are macrocyclic compounds consisting These molecules were synthesized such of four simple D-{pi}-A units bridged by methylene groups. These molecules were synthesized such that four D-n-A units of the calix[4]arene were aligned along the same direction with the calixarene in a cone conformation. These nonlinear optical super-chromophores were subsequently fabricated into covalently bound self-assembled monolayers on the surfaces of fused silica and silicon. Spectroscopic second harmonic generation (SHG) measurements were carried out to determine the absolute value of the dominant element of the nonlinear susceptibility, {Chi}{sub zzz}, and the average molecular alignment, {Psi}. We find a value of {Chi}{sub zzz}{approximately} 1.5 {times} 10{sup {minus}7} esu (60 pm/V) at a wavelength of 890 nm, and {Psi} {approximately} 36{degrees} with respect to the surface normal.
Date:
September 1, 1995
Creator:
Yang, Xiaoguang; McBranch, D.; Swanson, B. & Li, DeQuan
Object Type:
Article
System:
The UNT Digital Library
Atomic physics with highly charged ions. Progress report, September 1, 1994--August 31, 1995
Grant DE-FG02-94ER14444 was obtained from the FY94 ARIM fund account of Energy Research. These funds were requested to address several upgrades of the Macdonald Laboratory facility. The largest item is the relocation and upgrade of the He compressor associated with providing LHe to the Nb split-ring superconducting LINAC accelerator and the superconducting CRYEBIS ion source. The move is prompted by the need to reduce the noise and vibration levels in the personnel working space in the laboratory. Several other issues related to the relocation are being addressed at the same time, such as additional electrical service and overhead crane for compressor maintenance. The Ion-Compressor Relocation Project consists of six major components. All necessary planning and engineering are completed. Many of the upgrades consist of obtaining commercially available items which are being installed by our local staff in the Macdonald Laboratory. No unexpected complications stand in the way of completing all projects within the scope, budget and time frame of the project. Of the project`s major components, the tandem resistor upgrade, tandem foil stripper upgrade, and LINAC upgrade are all complete, the CRYEBIS upgrade is partially completed and on schedule, the LHe compressor upgrade is in the early stages of development …
Date:
September 1995
Creator:
Richard, P.
Object Type:
Report
System:
The UNT Digital Library
Operating new 55-gallon drum shufflers at Los Alamos
Two passive-active shufflers for the assay of uranium and plutonium have begun operation at Los Alamos National Laboratory. An extensive period of safety and technology assessments were made to meet laboratory and DOE certification requirements. Many design features of the shufflers are in place to assist the operator in using the instruments efficiently, effectively, and safely. A calibration for uranium oxide has been completed and applied to a variety of uranium-bearing inventory materials. A new calibration for MOX materials is nearly complete and additional uranium and plutonium materials will be measured in the near future.
Date:
September 1, 1995
Creator:
Hsue, F.; Hurd, J. R. & Rinard, P. M.
Object Type:
Article
System:
The UNT Digital Library
Long-term methanol vehicle test program. Final subcontract report, 1 November 1992--1 February 1995
Work was sperformed to determine effects of methanol fuel on engine performance and exhaust emissions during long-term use in a 1988 Chevrolet Corsica. Engine wear, gasket performance, fuel economy, emissions level, oil consumption, and overall vehicle performance were monitored over 22,000 miles. Baselines were established at the beginning for comparison: engine was disassembled, bearing/ring clearances and cam profiles were measured. Higher flow rate fuel injectors from AC Rochester were installed and the computer system calibrated for M100 fuel. The vehicle durability test increased oil consumption by 26% under cold-start conditions, 9% under hot start. Oil consumption under hot start was higher than under cold start by as much as 56%; effect of component temperatures on oil viscosity appears to be the cause. It is recommended that oil consumption of a gasoline-fueled vehicle be measured in order to normalize the effect of methanol operation on oil consumption, and to study the effect of steady-state and transient conditions on oil consumption.
Date:
September 1, 1995
Creator:
Jones, J. C. & Maxwell, T. T.
Object Type:
Report
System:
The UNT Digital Library
Mongolia wind resource assessment project
The development of detailed, regional wind-resource distributions and other pertinent wind resource characteristics (e.g., assessment maps and reliable estimates of seasonal, diurnal, and directional) is an important step in planning and accelerating the deployment of wind energy systems. This paper summarizes the approach and methods being used to conduct a wind energy resource assessment of Mongolia. The primary goals of this project are to develop a comprehensive wind energy resource atlas of Mongolia and to establish a wind measurement program in specific regions of Mongolia to identify prospective sites for wind energy projects and to help validate some of the wind resource estimates. The Mongolian wind resource atlas will include detailed, computerized wind power maps and other valuable wind resource characteristic information for the different regions of Mongolia.
Date:
September 7, 1998
Creator:
Elliott, D.; Chadraa, B. & Natsagdorj, L.
Object Type:
Article
System:
The UNT Digital Library
ICF quarterly report October-December 1998 volume 8, number 1
This issue of the ICF Quarterly Report focuses on the final section of the 192-arm, 1.8-MJ National Ignition Facility (NIF). We describe both technological advances necessary for optimal utilization of the delivered energy and the hohlraum physics resulting from extremely high energy densities. Two articles belong to the first category. The conversion of infrared light to ultraviolet occurs at the tripler in the NIF's Final Optics Assembly. It is then necessary to separate any unconverted (first- and second-harmonic) light from the tripled-frequency light passed to the target. Large-Aperture Color-Separation Gratings for Diverting Unconverted Light Away from the NIF Target describes the design and fabrication of novel diffraction gratings that fulfill this function. In both direct- and indirect-drive ICF, the symmetry of the capsule as it compresses is crucial. The NIF will have 48 clusters of four beams incident on targets. Optimization of Beam Angles for the National Ignition Facility (p. 15) presents the rationale used to assign beam angles for cylindrical indirect drive while still allowing direct-drive and tetrahedral indirect-drive experiments to be performed.
Date:
September 8, 1998
Creator:
Feit, M
Object Type:
Report
System:
The UNT Digital Library
Calcination/dissolution chemistry development Fiscal year 1995
The task {open_quotes}IPC Liaison and Chemistry of Thermal Reconstitution{close_quotes} is a $300,000 program that was conducted in Fiscal Year (FY) 1995 with U.S. Department of Energy (DOE) Office of Research and Development (EM-53) Efficient Separations and Processing Crosscutting Program supported under technical task plan (TTP) RL4-3-20-04. The principal investigator was Cal Delegard of the Westinghouse Hanford Company (WHC). The task encompassed the following two subtasks related to the chemistry of alkaline Hanford Site tank waste: (1) Technical Liaison with the Institute of Physical Chemistry of the Russian Academy of Science (IPC/RAS) and its research into the chemistry of transuranic elements (TRU) and technetium (Tc) in alkaline media. (2) Laboratory investigation of the chemistry of calcination/dissolution (C/D) (or thermal reconstitution) as an alternative to the present reference Hanford Site tank waste pretreatment flowsheet, Enhanced Sludge Washing (ESW). This report fulfills the milestone for the C/D subtask to {open_quotes}Provide End-of-Year Report on C/D Laboratory Test Results{close_quotes} due 30 September 1995. A companion report, fulfilling the milestone to provide an end-of-year report on the IPC/RAS liaison, also has been prepared.
Date:
September 1, 1995
Creator:
Delegard, C.H.
Object Type:
Report
System:
The UNT Digital Library
Small Wind Turbine Applications: Current Practice in Colorado
Numerous small wind turbines are being used by homeowners in Colorado. Some of these installations are quite recent while others date back to the federal tax-credit era of the early 1980s. Through visits with small wind turbine owners in Colorado, I have developed case studies of six small wind energy applications focusing on the wind turbine technology, wind turbine siting, the power systems and electric loads, regulatory issues, and motivations about wind energy. These case studies offer a glimpse into the current state-of-the-art of small-scale wind energy and provide some insight into issues affecting development of a wider market.
Date:
September 30, 1999
Creator:
Green, J.
Object Type:
Article
System:
The UNT Digital Library
Water-Level Monitoring Plan for the Hanford Groundwater Monitoring Project
This document presents the water-level monitoring plan for the Hanford Groundwater Monitoring Project, conducted by the Pacific Northwest National Laboratory (PNNL). Water-level monitoring of the groundwater system beneath the Hanford Site is performed to fulfill the requirements of various state and federal regulations, orders, and agreements. The primary objective of this monitoring is to determine groundwater flow rates and directions. To meet this and other objectives, water-levels are measured annually in monitoring wells completed within the unconfined aquifer system, the upper basalt-confined aquifer system, and in the lower basalt-confined aquifers for surveillance monitoring. At regulated waste units, water levels are taken monthly, quarterly, semi-annually, or annually, depending on the hydrogeologic conditions and regulatory status of a given site. The techniques used to collect water-level data are described in this document along with the factors that affect the quality of the data and the strategies employed by the project to minimize error in the measurement and interpretation of water levels. Well networks are presented for monitoring the unconfined aquifer system, the upper basalt-confined aquifer system, and the lower basalt-confined aquifers, all at a regional scale (surveillance monitoring), as well as the local-scale well networks for each of the regulated waste units …
Date:
September 30, 1999
Creator:
Newcomer, D.R.; McDonald, J.P. & Chamness, M.A.
Object Type:
Report
System:
The UNT Digital Library
GYPSY field project in reservoir characterization. Quarterly progress report, April 1, 1995--June 30, 1995
We study the determination of possibly discontinuous reservoir parameter functions defined on two dimensional regions from sparse pointwise measurements supplemented with measurements of a nonlinear function of the parameter. The specific application we have in mind is that of determining a permeability function from core measurements and pressure data, cf. Our approach involves two steps. The first is to detect the discontinuous behavior, and the second is to isolate and refine the region containing it. For the first step we use a regularized output least squares procedure in which the reservoir mapping is approximated by linear combinations of bicubic B-splines. The regularization used is the H{sup 1} seminorm that is related to the potential energy functional of an elastic membrane. This regularization gives sufficient compactness to obtain the existence of a solution to the associated minimization problem while implying minimal additional smoothing. The result of the procedure is to obtain a discontinuous function. We then essentially subtract this function from the model coefficient thereby, at least intuitively, reducing the discontinuous behavior. In Section 2 we discuss the estimation of parameters by a regularized output least squares method in which there are data available in the form of measurements of permeability …
Date:
September 1, 1995
Creator:
O`Meara, D.J. Jr.
Object Type:
Report
System:
The UNT Digital Library