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CODA performance in the real world (open access)

CODA performance in the real world

The most ambitious implementation of the Jefferson Lab data acquisition system (CODA) to date is for the CLAS spectrometer in Experimental Hall B. CLAS has over 40,000 instrumented channels and uses up to 30 front-end (FASTBUS/VME) crates in the DAQ subsystem. During the initial experiments the authors found that performance of the fully instrumented DAQ system did not scale as expected based on single point to point benchmarks. Over the past year the authors have been able to study various performance bottlenecks in the CLAS DAQ system including front-end real time performance, switched 100BaseT Ethernet data transport, and online data distribution and recording. Performance tuning was necessary for components on both real time (VxWorks) and UNIX (Solaris) operating systems. In addition, a new efficient Event Transfer System (ET) was developed to provide faster online monitoring while having minimal impact on data throughput to storage. They discuss these issues and efforts to overcome the real world problems associated with running a high performance DAQ system on a variety of commercial hardware and software.
Date: June 1, 1999
Creator: Abbott, D.J.; Heyes, W.G.; Jastrzembski, E.; MacLeod, R.W.; Timmer, C. & Wolin, E.
Object Type: Article
System: The UNT Digital Library
Progress and Critical Issues for IFE Blanket and Chamber Research (open access)

Progress and Critical Issues for IFE Blanket and Chamber Research

Advances in high gain target designs for Inertial Fusion Energy (IFE), and the initiation of construction of large megajoule-class laser facilities in the U.S. (National Ignition Facility) and France (Laser-Megajoule) capable of testing the requirements for inertial fusion ignition and propagating burn, have improved the prospects for IFE. Accordingly, there have recently been modest increases in the US fusion research program related to the feasibility of IFE. These research areas include heavy-ion accelerators, Krypton-Fluoride (KrF) gas lasers, diode-pumped, solid-state (DPSSL) lasers, IFE target designs for higher gains, feasibility of low cost IFE target fabrication and accurate injection, and long-lasting IFE fusion chambers and final optics. Since several studies of conceptual IFE power plant and driver designs were completed in 1992-1996 [1-5], U.S. research in the IFE blanket, chamber, and target technology areas has focused on the critical issues relating to the feasibility of IFE concepts towards the goal of achieving economically-competitive and environmentally-attractive fusion energy. This paper discusses the critical issues in these areas, and the approaches taken to address these issues. The U.S. research in these areas, called IFE Chamber and Target Technologies, is coordinated through the Virtual Laboratory for Technology (VLT) formed by the Department of Energy in …
Date: June 23, 1999
Creator: Abdou, M.; Kulcinski, G. L.; Latkowski, J. F.; Logan, B. G.; Meier, W. R.; Moir, R. W. et al.
Object Type: Article
System: The UNT Digital Library
A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays (open access)

A Preliminary measurement of the gluon splitting rate into b\bar{b} pairs in hadronic Z0 decays

We present a measurement of the rate of gluon splitting into bottom quarks, g --> b anti-b, in hadronic Z<sup>0</sup> decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary avor. A topological vertex mass technique was used to tag the two jets with the smallest angle between them as b/anti-b. We obtained a rate of g --> b anti-b per hadronic event to be (3.07 ± 0.71(stat:) ± 0.66(syst:)) × 10&sup3; (preliminary).
Date: June 10, 1999
Creator: Abe, Toshinori
Object Type: Report
System: The UNT Digital Library
Surface Characterization of a Paper Web at the Wet End (open access)

Surface Characterization of a Paper Web at the Wet End

We present an algorithm for the detection and representation of structures and non-uniformities on the surface of a paper web at the wet end (slurry). This image processing/analysis algorithm is developed as part of a complete on-line web characterization system. Images of the slurry, carried by a fast moving table, are obtained using a stroboscopic light and a CCD camera. The images have very poor contrast and contain noise from a variety of sources. Those sources include the acquisition system itself, the lighting, the vibrations of the moving table being imaged, and the scattering water from the same table's movement. After many steps of enhancement, conventional edge detection methods were still inconclusive and were discarded. The facet model algorithm, is applied to the images and is found successful in detecting the various topographic characteristics of the surface of the slurry. Pertinent topographic elements are retained and a filtered image is computed based on the general appearance and characteristics of the structures in question. Morphological operators are applied to detect and segment regions of interest. Those regions are then filtered according to their size, elongation, and orientation.Their bounding rectangles are computed and superimposed on the original image. Real time implementation of …
Date: June 23, 1999
Creator: Abidi, B.R.; Goddard, J.S. & Sari-Sarraf, H.
Object Type: Article
System: The UNT Digital Library
Stable isotope investigations of chlorinated aliphatic hydrocarbons. (open access)

Stable isotope investigations of chlorinated aliphatic hydrocarbons.

Stable isotope ratio measurements for carbon (C) and chlorine (Cl) can be used to elucidate the processes affecting transformation and transportation of chlorinated aliphatic hydrocarbons (CAHs) in the environment. Methods recently developed in our laboratory for isotopic analysis of CAHs have been applied to laboratory measurements of the kinetic isotope effects associated with aerobic degradation of dichloromethane (DCM) and with both anaerobic and aerobic cometabolic degradation of trichlomethene (TCE) in batch and column microbial cultures. These experimental determinations of fractionation factors are crucial for understanding the behavior of CAHs in complex natural systems, where the extent of biotransformation can be masked by dispersion and volatilization. We have also performed laboratory investigations of kinetic isotope effects accompanying evaporation of CAHs, as well as field investigations of natural attenuation and in situ remediation of CAHs in a number of contaminated shallow aquifers at sites operated by the federal government and the private sector.
Date: June 1, 1999
Creator: Abrajano, T.; Heraty, L. J.; Holt, B. D.; Huang, L. & Sturchio, N. C.
Object Type: Article
System: The UNT Digital Library
Oxidation of K-West Basin Spent Nuclear Fuel in Moist Helium Atmosphere (open access)

Oxidation of K-West Basin Spent Nuclear Fuel in Moist Helium Atmosphere

None
Date: June 15, 1999
Creator: Abrefah, J. & Sell, R. L.
Object Type: Report
System: The UNT Digital Library
The Migration and Entrapment of DNAPLs in Physically and Chemically Heterogeneous Porous Media (open access)

The Migration and Entrapment of DNAPLs in Physically and Chemically Heterogeneous Porous Media

Dense nonaqueous phase liquids (DNAPLs) are common subsurface contaminants at many Department of Energy (DOE) hazardous waste sites. The migration and entrapment of DNAPLs at these sites is greatly influenced by subsurface heterogeneity, both physical and chemical. Unfortunately, the physics of DNAPL flow in chemically heterogeneous systems is poorly understood and, hence, multiphase flow simulators typically assume that subsurface soils are completely water-wet (chemically homogeneous). The primary objective of this research is to improve our understanding of and ability to simulate the influence of subsurface chemical heterogeneities on DNAPL flow and entrapment in the saturated zone. Laboratory and numerical investigations are being conducted for a matrix of organic contaminants and porous media encompassing a range of wettability characteristics. Specific project objectives include: (1) quantification of system wettability and interfacial tensions; (2) determination of hydraulic property relations; (3) investigation of DNAPL infiltration behavior in two-dimensional systems; (4) modification of a continuum based multiphase flow simulator to account for coupled physical and chemical heterogeneity; and (5) exploration of the migration of DNAPLs and the development of innovative remediation schemes under heterogeneous conditions using this model.
Date: June 1, 1999
Creator: Abriola, Linda M.; Demond, Avery H. & Glass, Robert
Object Type: Report
System: The UNT Digital Library
The ASCI Network for SC '98: Dense Wave Division Multiplexing for Distributed and Distance Computing (open access)

The ASCI Network for SC '98: Dense Wave Division Multiplexing for Distributed and Distance Computing

This document highlights the DISCOM's Distance computing and communication team activities at the 1998 Supercomputing conference in Orlando, Florida. This conference is sponsored by the IEEE and ACM. Sandia National Laboratories, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory have participated in this conference for ten years. For the last three years, the three laboratories have a joint booth at the conference under the DOE's ASCI, Accelerated Strategic Computing Initiatives. The DISCOM communication team uses the forum to demonstrate and focus communications and networking developments. At SC '98, DISCOM demonstrated the capabilities of Dense Wave Division Multiplexing. We exhibited an OC48 ATM encryptor. We also coordinated the other networking activities within the booth. This paper documents those accomplishments, discusses the details of their implementation, and describes how these demonstrations support overall strategies in ATM networking.
Date: June 1, 1999
Creator: Adams, Roger L.; Butman, Wayne; Martinez, Luis G.; Pratt, Thomas J. & Vahle, Michael O.
Object Type: Report
System: The UNT Digital Library
Thermodynamics of the Volatilization of Actinind metals in the High-Temperature Treatment of Radioactive Wastes (open access)

Thermodynamics of the Volatilization of Actinind metals in the High-Temperature Treatment of Radioactive Wastes

We are performing a detailed study of the volatilization behavior of U, Pu and possibly Am and Np under conditions relevant to the thermal treatment (destruction) of actinide containing organic-based mixed and radioactive wastes. The primary scientific goal of the work is to develop a basic thermochemical understanding of actinide volatilization and partitioning/speciation behavior in the thermal processes that are central to DOE/EM's mixed waste treatment program. This subject addresses at least two key technical needs/problem areas recently identified by DOE/EM's Office of Science & Technology: emission-free destruction of organic wastes, and interactions between actinides and organic residues in materials stabilization. A sound basis for designing safe and effective treatment systems, and the ability to allay public concerns about radioactive fugitive emissions, will be the principal benefits of the project. The proposed work is a combination of experimental studies and thermodynamic modeling. Vapor pressure measurements will be made to determine U, Pu and possibly Am volatile species and the extent of their volatilization when UO2/U3O8, PuO2 and AmO2 solids are heated to temperatures of 500 to1200 C under pyrolyzing (reducing) conditions or under oxidizing conditions in the presence of chlorine. Work on uranium volatilization under reducing conditions is being performed …
Date: June 1, 1999
Creator: Adamson, Martyn, G. & Olander, Donald R.
Object Type: Report
System: The UNT Digital Library
Development and Testing of the NIF Prototype Module (open access)

Development and Testing of the NIF Prototype Module

The NIF Power Conditioning System (PCS) is required to deliver -68 kJ to each of the 3840 flashlamp pairs in the NIF laser in a current pulse with a peak of -500 kA and rise time of- 150 &micro;s. The PCS will consist of 192 modules each of which drive 20 lamp-pairs. Each module will basically be a 6 rnF capacitor bank with a nominal charge voltage of 23.5 kV which is switched by a single pressurized air gas switch to 20 RG-220 cables that are connected to individual lamp loads. In addition each module will have a number of subsystems including; a lamp pre-ionization system, power supplies, isolation circuits, trigger systems, safety dump systems, gas system, and an embedded control system. A module will also include components whose primary function is to limit fault currents and thus minimize collateral damage in faults. In the Prototype Development and Testing effort at Sandia National Laboratories all of these were integrated into a single system and proper fimctionality was demonstrated. Extensive testing was done at nominal operating levels into resistive dummy loads and some testing in fault modes was also done. A description of the system and a summary of testing is …
Date: June 25, 1999
Creator: Adcock, J.; Harjes, C.; Mowrer, G. & Wilson, M.
Object Type: Article
System: The UNT Digital Library
Risk management considerations for seismic upgrading of an older facility for short-term residue stabilization (open access)

Risk management considerations for seismic upgrading of an older facility for short-term residue stabilization

Building 707 and its addition, Building 707A, were selected, after the production mission of Rocky Flats was terminated a few years ago, to stabilize many of the plutonium residues remaining at the site by 2002. The facility had undergone substantial safety improvements to its safety systems and conduct of operations for resumption of plutonium operations in the early 1990s and appeared ideally suited for this new mission to support accelerated Site closure. During development of a new authorization basis, a seismic evaluation was performed. This evaluation addressed an unanalyzed expansion joint and suspect connection details for the precast concrete tilt-up construction and concluded that the seismic capacity of the facility is less than half of that determined by previous analysis. Further, potential seismic interaction was identified between a collapsing Building 707 and the seismically upgraded Building 707A, possibly causing the partial collapse of the latter. Both the operating contractor and the Department of Energy sought a sound technical basis for deciding how to proceed. This paper addresses the risks of the as-is facility and possible benefits of upgrades to support a decision on whether to upgrade the seismic capacity of Building 707, accept the risk of the as-is facility for …
Date: June 1, 1999
Creator: Additon, S. L.; Peregoy, W. L. & Foppe, T. L.
Object Type: Article
System: The UNT Digital Library
Detecting data and schema changes in scientific documents (open access)

Detecting data and schema changes in scientific documents

Data stored in a data warehouse must be kept consistent and up-to-date with the underlying information sources. By providing the capability to identify, categorize and detect changes in these sources, only the modified data needs to be transferred and entered into the warehouse. Another alternative, periodically reloading from scratch, is obviously inefficient. When the schema of an information source changes, all components that interact with, or make use of, data originating from that source must be updated to conform to the new schema. In this paper, the authors present an approach to detecting data and schema changes in scientific documents. Scientific data is of particular interest because it is normally stored as semi-structured documents, and it incurs frequent schema updates. They address the change detection problem by detecting data and schema changes between two versions of the same semi-structured document. This paper presents a graph representation of semi-structured documents and their schema before describing their approach to detecting changes while parsing the document. It also discusses how analysis of a collection of schema changes obtained from comparing several individual can be used to detect complex schema changes.
Date: June 8, 1999
Creator: Adiwijaya, I; Critchlow, T & Musick, R
Object Type: Article
System: The UNT Digital Library
Studies of ferroelectric heterostructure thin films, interfaces, and device-related processes via in situ analytical techniques. (open access)

Studies of ferroelectric heterostructure thin films, interfaces, and device-related processes via in situ analytical techniques.

The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMS) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and device processes relevant to device development. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed. Direct imaging of ferroelectric domains under applied electric fields can provide valuable information to understand domain dynamics in ferroelectric films. We discuss results of piezoresponse scanning force microscopy (SFM) imaging for nanoscale studies of polarization reversal …
Date: June 29, 1999
Creator: Aggarwal, S.; Auciello, O.; Dhote, A. M.; Gao, Y.; Gruen, D. M.; Im, J. et al.
Object Type: Article
System: The UNT Digital Library
Microstructural Properties of High Level Waste Concentrates and Gels with Raman And Infrared Spectroscopies (open access)

Microstructural Properties of High Level Waste Concentrates and Gels with Raman And Infrared Spectroscopies

Nearly half of the high level radioactive waste stored at Hanford is composed of highly alkaline concentrates referred to as either salt cakes or Double-Shell Slurry (DSS), depending on their compositions and processing histories. The major components of these concentrates are water, sodium hydroxide, and sodium salts of nitrate, nitrite, aluminate, carbonate, phosphate, and sulfate. In addition, there are varying amounts of assorted organic salts such as EDTA, glycolate, and citrate. Although measurements of the bulk properties of these wastes (e.g. viscosity, gel point, density) have been reported, little is known about how the macroscopic characteristics are related to the microscopic physico-chemical properties. Viscosity, solids volume percent, and gas retention can dramatically change with relatively small changes in composition and temperature. Furthermore, these same properties are important in determining safe storage conditions as well as in planning retrieval, pretreatment, and disposal of the wastes. The focus of this effort will be on aluminate chemistry since large inventories of waste with aluminum are located at Hanford and Savannah River and little is known about the microstructure of these complex mixtures.
Date: June 1, 1999
Creator: Agnew, Stephen F. & Johnston, Clifford T.
Object Type: Report
System: The UNT Digital Library
Microstructural Properties of High Level Waste Concentrates and Gels with raman and Infrared Spectroscopies (open access)

Microstructural Properties of High Level Waste Concentrates and Gels with raman and Infrared Spectroscopies

Background: Although aluminum species constitute a predominant proportion of tank wastes, the chemistry of aluminum in these alkaline solutions is inadequately understood. This is due, in part, to the extreme conditions of the HLW supernatant tank liquors. In REDOX waste, for example, the concentration of Al in HLW supernatants can exceed 1.5 M. In addition, the pH is often greater than 14, and the individual molar concentrations of Na+, NOi, and NOa- are in excess of 2 M. As a consequence of the high molar concentrations of A13+, Na+, NO;z-, and N03-, the activity of water in these supernatant solutions is greatly decreased. The concentration of water in these solutions, is in the range of 35-45 M, a significant reduction from the pure bulk water value of 55 M. On the molecular scale, there is not enough water present to satisfy the hydration requirements of the Na+ and AI(O) ions in the alkaline aluminum solutions. Thus, most of the water present in the HLW supernatants is chemically ''tied up'' as hydrated water around the Na+ and Al(OH)d- ions, as well as structural water present in solid aluminate hydrates. The solution-solid phase behavior of the HLW supernatants can be thought of …
Date: June 1, 1999
Creator: Agnew, Stephen F. & Schoonover, Jon R.
Object Type: Report
System: The UNT Digital Library
PARTICLE TRANSPORT AND DEPOSITION IN THE HOT-GAS FILTER AT WILSONVILLE (open access)

PARTICLE TRANSPORT AND DEPOSITION IN THE HOT-GAS FILTER AT WILSONVILLE

Particle transport and deposition in the Wilsonville hot-gas filter vessel is studied. The filter vessel contains a total of 72 filters, which are arranged in two tiers. These are modeled by six upper and one lower cylindrical effective filters. An unstructured grid of 312,797 cells generated by GAMBIT is used in the simulations. The Reynolds stress model of FLUENT{trademark} (version 5.0) code is used for evaluating the gas mean velocities and root mean-square fluctuation velocities in the vessel. The particle equation of motion includes the drag, the gravitational and the lift forces. The turbulent instantaneous fluctuation velocity is simulated by a filtered Gaussian white-noise model provided by the FLUENT code. The particle deposition patterns are evaluated, and the effect of particle size is studied. The effect of turbulent dispersion, the lift force and the gravitational force are analyzed. The results show that the deposition pattern depends on particle size. Turbulent dispersion plays an important role in transport and deposition of particles. Lift and gravitational forces affect the motion of large particles, but has no effect on small particles.
Date: June 24, 1999
Creator: Ahmadi, Goodarz
Object Type: Report
System: The UNT Digital Library
Fuel-flexible partial oxidation reforming of hydrocarbons for automotive applications. (open access)

Fuel-flexible partial oxidation reforming of hydrocarbons for automotive applications.

Micro-reactor tests indicate that our partial oxidation catalyst is fuel-flexible and can reform conventional (gasoline and diesel) and alternative (ethanol, methanol, natural gas) fuels to hydrogen rich product gases with high hydrogen selectivity. Alcohols are reformed at lower temperatures (&lt; 600 C) while alkanes and unsaturated hydrocarbons require slightly higher temperatures. Cyclic hydrocarbons and aromatics have also been reformed at relatively low temperatures, however, a different mechanism appears to be responsible for their reforming. Complex fuels like gasoline and diesel, which are mixtures of a broad range of hydrocarbons, require temperatures of &gt; 700 C for maximum hydrogen production.
Date: June 7, 1999
Creator: Ahmed, S.; Carter, J. D.; Kopasz, J. P.; Krumpelt, M. & Wilkenhoener, R.
Object Type: Article
System: The UNT Digital Library
Contaminant-Organic Complexes, Their Structure and Energetics in Surface Decontamination Processes (open access)

Contaminant-Organic Complexes, Their Structure and Energetics in Surface Decontamination Processes

There are a wide variety of compounds that are naturally occurring biodegradable organic chelates (siderophores) that appear to be more effective at oxide dissolution and actinide complexation than EDTA or other organic acids now used in decontamination processes. These chelates bind hard acids [Fe(III) and actinides(IV)] with extraordinarily high affinities. For example, the binding constant for the siderophore enterobactin with iron is about 1050, and its binding constant for Pu(IV) is estimated to be as high. Hence, this project is investigating the efficacy of using siderophores (or siderophore-like chelates) as decontamination agents of metal surfaces. The specific goals of this project are as follows: 1. develop an understanding of the surface interaction between siderophores (and their functional moieties), iron, and actinide oxides; their surface chemical properties that foster their dissolution; and the conditions that maximize that dissolution 2. develop the computational tools necessary to predict the reactivity of different siderophore functional groups toward oxide dissolution and actinide(IV) solubilization 3. identify likely candidate chelates for use in decontamination processes. To meet these objectives, the project combines molecular spectroscopy and computational chemistry to provide basic information on the structure and bonding of siderophore functional groups to metal (iron and uranium) oxide specimens …
Date: June 1999
Creator: Ainsworth, Calvin C.; Friedrich, Donald M.; Hay, Benjamin P.; Myneni, Satish C. B. & Traina, Samuel J.
Object Type: Report
System: The UNT Digital Library
Three-Body Breakup Dynamics in Dissociative Recombination (open access)

Three-Body Breakup Dynamics in Dissociative Recombination

Using the CRYRing Facility in Stockholm Coupled with an MCP-CCD detector, and a differential stopping foil, we have determined dynamic parameters in the three-body dissociative recombination of H<sub>2</sub>O<sup>+</sup>. These include the distribution between the O(<sup>3</sup>P) and O(<sup>1</sup>D) channels, the distribution of H atom recoil energies in the O(<sup>3</sup>P) channel and the distribution of angles between the two departing H atoms.
Date: June 16, 1999
Creator: Al-Khalili, A.; Datz, S.; Derkatch, A.; Larsson, M.; Rosén, S.; Shi, W. et al.
Object Type: Article
System: The UNT Digital Library
Multivariate Analysis of Seismic Field Data (open access)

Multivariate Analysis of Seismic Field Data

This report includes the details of the model building procedure and prediction of seismic field data. Principal Components Regression, a multivariate analysis technique, was used to model seismic data collected as two pieces of equipment were cycled on and off. Models built that included only the two pieces of equipment of interest had trouble predicting data containing signals not included in the model. Evidence for poor predictions came from the prediction curves as well as spectral F-ratio plots. Once the extraneous signals were included in the model, predictions improved dramatically. While Principal Components Regression performed well for the present data sets, the present data analysis suggests further work will be needed to develop more robust modeling methods as the data become more complex.
Date: June 1999
Creator: Alam, M. Kathleen
Object Type: Report
System: The UNT Digital Library
Eligibility of Indoor Plumbing Under Alaska Sanitation Infrastructure Grant Program (open access)

Eligibility of Indoor Plumbing Under Alaska Sanitation Infrastructure Grant Program

This is a memorandum to answer questions in regards to the Village Safe Water (VSW) Program,
Date: June 17, 1999
Creator: Albright, Richard
Object Type: Text
System: The UNT Digital Library
Observation of ionization instability of intense laser pulses (open access)

Observation of ionization instability of intense laser pulses

Theoretical analysis and preliminary experiment on ionization instability of intense laser pulses in ionizing plasmas are presented. The ionization instability is due to the dependence of the ionization rate on the laser intensity and scatters the laser energy off the original propagation direction.
Date: June 25, 1999
Creator: Alexeev, I.; Antonsen, T. M.; Li, Y.; Milchberg, H. M. & Nikitin, S.
Object Type: Article
System: The UNT Digital Library
Searching for R-Parity Violation at Run-II of the Tevatron. (open access)

Searching for R-Parity Violation at Run-II of the Tevatron.

The authors present an outlook for possible discovery of supersymmetry with broken R-parity at Run II of the Tevatron. They first present a review of the literature and an update of the experimental bounds. In turn they then discuss the following processes: (1) resonant slepton production followed by R{sub P} decay, (a) via LQD{sup c} and (b) via LLE{sup c}; (2) how to distinguish resonant slepton production from Z{prime} or W{prime} production; (3) resonant slepton production followed by the decay to neutralino LSP, which decays via LQD{sup c}; (4) resonant stop production followed by the decay to a chargino, which cascades to the neutralino LSP; (5) gluino pair production followed by the cascade decay to charm squarks which decay directly via L{sub 1}Q{sub 2}D{sub 1}{sup c}; (6) squark pair production followed by the cascade decay to the neutralino LSP which decays via L{sub 1}Q{sub 2}D{sub 1}{sup c}; (7) MSSM pair production followed by the cascade decay to the LSP which decays (a) via LLE{sup c}, (b) via LQD{sup c}, and (c) via U{sup c}D{sup c}D{sup c}, respectively; and (8) top quark and top squark decays in spontaneous R{sub P}.
Date: June 22, 1999
Creator: Allanach, B.; Banerjee, S.; Berger, E. L.; Chertok, M.; de Campos, F.; Dedes, A. et al.
Object Type: Article
System: The UNT Digital Library
Developing a CD-CBM Anticipatory Approach for Cavitation - Defining a Model-Based Descriptor Consistent Across Processes, Phase 1 Final Report Context-Dependent Prognostics and Health Assessment: A New Paradigm for Condition-based Maintenance SBIR Topic No. N98-114 (open access)

Developing a CD-CBM Anticipatory Approach for Cavitation - Defining a Model-Based Descriptor Consistent Across Processes, Phase 1 Final Report Context-Dependent Prognostics and Health Assessment: A New Paradigm for Condition-based Maintenance SBIR Topic No. N98-114

The objective of this research, and subsequent testing, was to identify specific features of cavitation that could be used as a model-based descriptor in a context-dependent condition-based maintenance (CD-CBM) anticipatory prognostic and health assessment model. This descriptor is based on the physics of the phenomena, capturing the salient features of the process dynamics. The test methodology and approach were developed to make the cavitation features the dominant effect in the process and collected signatures. This would allow the accurate characterization of the salient cavitation features at different operational states. By developing such an abstraction, these attributes can be used as a general diagnostic for a system or any of its components. In this study, the particular focus will be pumps. As many as 90% of pump failures are catastrophic. They seem to be operating normally and fail abruptly without warning. This is true whether the failure is sudden hardware damage requiring repair, such as a gasket failure, or a transition into an undesired operating mode, such as cavitation. This means that conventional diagnostic methods fail to predict 90% of incipient failures and that in addressing this problem, model-based methods can add value where it is actually needed.
Date: June 1, 1999
Creator: Allgood, G. O.; Dress, W. B. & Kercel, S. W.
Object Type: Report
System: The UNT Digital Library