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Multi-grid and ICCG for problems with interfaces

Description: Computation times for the multi-grid (MG) algorithm, the incomplete Cholesky conjugate gradient (ICCG) algorithm (J. Comp. Phys. 26, 43-65 (1978); Math. Comp. 31, 148-162 (1977)), and the modified ICCG (MICCG) algorithm (BIT 18, 142-156 (1978)) to solve elliptic partial differential equations are compared. The MICCG and ICCG algorithms are more robust than the MG for general positive definite systems. A major advantage of the MG algorithm is that the structure of the problem can be exploited to… more
Date: January 1, 1980
Creator: Dendy, J.E. & Hyman, J.M.
Partner: UNT Libraries Government Documents Department
open access

Neutron scattering cross sections for /sup 232/Th and /sup 238/U inferred from proton scattering and charge exchange measurements. [7 MeV, 26 and 27 MeV]

Description: Differential cross sections for the (p,n) reactions to the isobaric analog states (IAS) of /sup 232/Th and /sup 238/U targets were measured at 26 and 27 MeV. The analysis of the data was done in conjunction with the proton elastic and inelastic (2/sup +/, 4/sup +/, 6/sup +/) differential cross sections measured at 26 MeV. Because collective effects are important in this mass region, deformed coupled-channels calculations were carried out for the simultaneous analysis of the proton and neutron o… more
Date: January 1, 1980
Creator: Hansen, L. F.; Grimes, S. M.; Pohl, B. A.; Poppe, C. H. & Wong, C.
Partner: UNT Libraries Government Documents Department
open access

Statistical analysis of the DWPF prototypic sampler

Description: The DWPF process will be controlled using assay measurements on samples of feed slurry. These slurries are radioactive, and thus will be sampled remotely. A Hydraguard{trademark} pump-driven sampler system will be used as the remote sampling device. A prototype Hydraguard{trademark} sampler has been studied in a full-scale mock-up of a DWPF process vessel. Two issues were of dominant interest: (1) what accuracy and precision can be provided by such a pump-driven sampler in the face of the slurr… more
Date: January 1, 1991
Creator: Postles, R.L.; Reeve, C.P.; Jenkins, W.J. & Bickford, D.F.
Partner: UNT Libraries Government Documents Department
open access

Full Wave Analysis of RF Signal Attenuation in a Lossy Rough Surface Cave using a High Order Time Domain Vector Finite Element Method

Description: We present a computational study of signal propagation and attenuation of a 200 MHz planar loop antenna in a cave environment. The cave is modeled as a straight and lossy random rough wall. To simulate a broad frequency band, the full wave Maxwell equations are solved directly in the time domain via a high order vector finite element discretization using the massively parallel CEM code EMSolve. The numerical technique is first verified against theoretical results for a planar loop antenna in a … more
Date: October 31, 2005
Creator: Pingenot, J; Rieben, R; White, D & Dudley, D
Partner: UNT Libraries Government Documents Department
open access

A Global Approach to the Physics Validation of Simulation Codes for Future Nuclear Systems

Description: This paper presents a global approach to the validation of the parameters that enter into the neutronics simulation tools for advanced fast reactors with the objective to reduce the uncertainties associated to crucial design parameters. This global approach makes use of sensitivity/uncertainty methods; statistical data adjustments; integral experiment selection, analysis and “representativity” quantification with respect to a reference system; scientifically based cross section covariance data … more
Date: September 1, 2008
Creator: Palmiotti, Giuseppe; Salvatores, Massimo; Aliberti, Gerardo; Hiruta, Hikarui; McKnight, R.; Oblozinsky, P. et al.
Partner: UNT Libraries Government Documents Department
open access

Fast Flux Test Facility noise data management

Description: An extensive collection of spectra from an automated data collection system at the Fast Flux Test Facility has features from neutron data extracted and managed by database software. Inquiry techniques, including screening, applied to database results show the influences of control rods on wideband noise and, more generally, abilities to detect diverse types of off-normal noise. Uncovering a temporary 0.1-Hz resonance shift gave additional diagnostic information on a 13-Hz mechanical motion char… more
Date: January 1, 1987
Partner: UNT Libraries Government Documents Department
open access

Reliability of the Solar One plant during the power production phase.

Description: Solar One is the world's largest central receiver power plant. During the last 4 years the plant availability was 80%, 83%, and 96%, respectively, during hours of sunshine. This reliability is considered to be excellent considering the plant is a first-of-a-kind facility and because it has been subjected to daily cyclic service. In this paper we present the frequencies and causes of the plant outages that occurred. The ten most important causes comprised 72% of the total outage time. Qualitativ… more
Date: January 1, 1989
Creator: Kolb, Gregory J. & Lopez, Charles W.
Partner: UNT Libraries Government Documents Department
open access

An organizational survey of the Los Alamos Site

Description: An Organizational Survey (OS) was administered at the Los Alamos Site that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental, safety, and health concern, hazardous nature of work, safety and overall job satisfaction. The purpose of the OS is to measure in a quantitative and objective way the notion of culture;'' that is, the values, attitudes, and beliefs of the individual… more
Date: November 1, 1991
Creator: Shurberg, D.A. & Haber, S.B.
Partner: UNT Libraries Government Documents Department
open access

Environmental restoration and statistics: Issues and needs

Description: Statisticians have a vital role to play in environmental restoration (ER) activities. One facet of that role is to point out where additional work is needed to develop statistical sampling plans and data analyses that meet the needs of ER. This paper is an attempt to show where statistics fits into the ER process. The statistician, as member of the ER planning team, works collaboratively with the team to develop the site characterization sampling design, so that data of the quality and quantity… more
Date: October 1, 1991
Creator: Gilbert, R.O.
Partner: UNT Libraries Government Documents Department
open access

Scavenging ratios based on inflow air concentrations

Description: Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, … more
Date: July 1, 1991
Creator: Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N. & Thorp, J.M.
Partner: UNT Libraries Government Documents Department
open access

Validation study for secretarial/administrative classifications using computer-based testing

Description: This paper presents the results of a content and concurrent criterion-related validity study conducted at Los Alamos National Laboratory for clerical, secretarial and administrative classifications using computer-based testing. The advantages and disadvantages of different types of testing software incorporated in the study are explored. Job analysis methodology, adverse impact analysis, procedure for establishing cut-off score and problems associated with criterion development and restriction … more
Date: January 1, 1991
Creator: Burns, J.M.
Partner: UNT Libraries Government Documents Department
open access

Forecasting urban highway travel for year 2005

Description: As part of a study aimed at estimating suburban highway needs for year 2005, models were developed for forecasting daily vehicle miles of travel (DVMT) for urban areas and its distribution by highway functional class, urban location, and urban area size. A regression model combining both time series and cross-sectional data is used to establish the relationship between the per capita DVMT of 339 urban areas in the United States and a set of explanatory variables including real income, employmen… more
Date: August 1, 1990
Creator: Miaou, Shaw-Pin (Tennessee Univ., Knoxville, TN (USA). Transportation Center); Rathi, A.K.; Southworth, F. & Greene, D.L. (Oak Ridge National Lab., TN (USA))
Partner: UNT Libraries Government Documents Department
open access

Estimating monthly and state-level NO sub x , SO sub 2 , VOC and CO sub 2 emissions using the MSCET database

Description: This paper describes the Month and State Current Emission Trends (MSCET) database. It describes the methodology used to estimate NO{sub x}, SO{sub 2}, VOC, and CO{sub 2} emissions and the data sources used by the methodology. Selected emissions results from the database are presented. 2 refs., 6 figs.
Date: January 1, 1992
Creator: Cilek, C.M. & Kohout, E.
Partner: UNT Libraries Government Documents Department
open access

The tau decay mode problem

Description: The problem of understanding the branching fractions of the 1-charged particle decay modes of the /tau/ lepton is reviewed. The emphasis is on a recent study by K.G. Hayes and M.L. Perl of the statistical validity of the branching fraction measurements. Unconventional explanations of the problem, none of them satisfactory, are also discussed. 25 refs., 4 tabs.
Date: May 1, 1988
Creator: Perl, M. L.
Partner: UNT Libraries Government Documents Department
open access

Energy Proportionality and Performance in Data Parallel Computing Clusters

Description: Energy consumption in datacenters has recently become a major concern due to the rising operational costs andscalability issues. Recent solutions to this problem propose the principle of energy proportionality, i.e., the amount of energy consumedby the server nodes must be proportional to the amount of work performed. For data parallelism and fault tolerancepurposes, most common file systems used in MapReduce-type clusters maintain a set of replicas for each data block. A coveringset is a group… more
Date: February 14, 2011
Creator: Kim, Jinoh; Chou, Jerry & Rotem, Doron
Partner: UNT Libraries Government Documents Department
open access

Gridded state maps of wind electric potential

Description: Estimates of wind electric potential and available windy land area in the contiguous United States, calculated in 1991, have been revised by incorporating actual data on the distribution of environmental exclusion areas where wind energy development would be prohibited or severely restricted. The new gridded data base with actual environmental exclusion areas, in combination with a 'moderate' land-use scenario, is the basis for developing the first gridded maps of available windy land and wind … more
Date: October 1, 1992
Creator: Schwartz, M. N.; Elliott, D. L. & Gower, G. L.
Partner: UNT Libraries Government Documents Department
open access

Statistical estimation of process holdup

Description: Estimates of potential process holdup and their random and systematic error variances are derived to improve the inventory difference (ID) estimate and its associated measure of uncertainty for a new process at the Savannah River Plant. Since the process is in a start-up phase, data have not yet accumulated for statistical modelling. The material produced in the facility will be a very pure, highly enriched 235U with very small isotopic variability. Therefore, data published in LANL's uncl… more
Date: January 1, 1988
Creator: Harris, S P
Partner: UNT Libraries Government Documents Department
open access

Self limiting features of accidental criticality in a solution system

Description: Experience with the SHEBA solution critical assembly during validation testing of accidental criticality alarm detectors provided several insights into the character of potential accidental excursions. Two observations were of particular interest. First, it is nearly impossible to maintain a solution system, particularly one employing low-enrichment material, in a constant state. If super-critical, the system will heat up, expand (or form bubbles), return to a sub-critical state, and shut down … more
Date: January 1, 1988
Creator: Malenfant, R.E.
Partner: UNT Libraries Government Documents Department
open access

Central nervous system tumors and related intracranial pathologies in radium dial workers

Description: Among the female radiation workers in the radium dial industry there is no overall excess of brain or central nervous system tumors. A significant excess did appear, however, in one of three major cohorts; the excess was not due to an excess of gliomas and cannot be ascribed with certainty to radium or external radiation. A significant proportional excess of tumors outside the brain was observed, and is consistent with irradiation of nervous system tissue from adjacent bone. Early deaths from b… more
Date: January 1, 1988
Creator: Stebbings, J.H. & Semkiw, W.
Partner: UNT Libraries Government Documents Department
open access

New Accelerated Testing and Lifetime Modeling Methods Promise Faster Development of More Durable MEAs

Description: For the successful commercialization of fuel cell technology, it is imperative that membrane electrode assembly (MEA) durability is understood and quantified. MEA lifetimes of 40,000 hours remain a key target for stationary power applications. Since it is impractical to wait 40,000 hours for durability results, it is critical to learn as much information as possible in as short a time period as possible to determine if an MEA sample will survive past its lifetime target. Consequently, 3M has ut… more
Date: November 1, 2005
Creator: Pierpont, D. M.; Hicks, M. T.; Turner, P. L. & Watschke, T. M.
Partner: UNT Libraries Government Documents Department
open access

Feasibility of quantitative performance measures for evaluating nuclear power plant operators

Description: A more valid measure of team performance in nuclear power plants is needed. A study is described which was oriented towards evaluating the feasibility of synthesizing performance measures by deriving measures for crews responding to an off-normal event in a full-scope simulator. The thesis was that performance assessment is based on the subjective judgment of training instructors. The procedure used to synthesize the performance measure consisted of: identification of the factors believed to be… more
Date: January 1, 1989
Creator: Carter, R. J.; Connelly, E. M. & Krois, P. A.
Partner: UNT Libraries Government Documents Department
open access

Assessment of the basis for modeling releases from plutonium oxidation

Description: Ideally, a model of the release of plutonium aerosols from plutonium during oxidation or combustion should begin from a description of the plutonium material and its surroundings and proceed unequivocally to a situation-dependent estimate of the amount of oxide released and its size distribution. Such a model would need to provide a description of the heat- and mass-transfer processes involved and link them directly to the rate of aerosol production. The first step, the description of heat and … more
Date: August 1, 1990
Creator: Mahoney, L. A. & Mishima, J.
Partner: UNT Libraries Government Documents Department
open access

The Evolution of a Hierarchical Partitioning Algorithm for Large-Scale Scientific Data: Three Steps of Increasing Complexity

Description: As scientific data sets grow exponentially in size, the need for scalable algorithms that heuristically partition the data increases. In this paper, we describe the three-step evolution of a hierarchical partitioning algorithm for large-scale spatio-temporal scientific data sets generated by massive simulations. The first version of our algorithm uses a simple top-down partitioning technique, which divides the data by using a four-way bisection of the spatio-temporal space. The shortcomings of … more
Date: April 16, 2003
Creator: Baldwin, C.; Eliassi-Rad, T.; Abdulla, G. & Critchlow, T.
Partner: UNT Libraries Government Documents Department
open access

International technology exchange in support of the Defense Waste Processing Facility wasteform production

Description: The nearly completed Defense Waste Processing Facility (DWPF) is a Department of Energy (DOE) facility at the Savannah River Site that is designed to immobilize defense high level radioactive waste (HLW) by vitrification in borosilicate glass and containment in stainless steel canisters suitable for storage in the future DOE HLW repository. The DWPF is expected to start cold operation later this year (1990), and will be the first full scale vitrification facility operating in the United States,… more
Date: August 23, 1989
Creator: Kitchen, Bruce G.
Partner: UNT Libraries Government Documents Department
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