Resource Type

Degree Department

States

201 Matching Results

Results open in a new window/tab.

Emerging energy-efficient technologies for industry (open access)

Emerging energy-efficient technologies for industry

For this study, we identified about 175 emerging energy-efficient technologies in industry, of which we characterized 54 in detail. While many profiles of individual emerging technologies are available, few reports have attempted to impose a standardized approach to the evaluation of the technologies. This study provides a way to review technologies in an independent manner, based on information on energy savings, economic, non-energy benefits, major market barriers, likelihood of success, and suggested next steps to accelerate deployment of each of the analyzed technologies. There are many interesting lessons to be learned from further investigation of technologies identified in our preliminary screening analysis. The detailed assessments of the 54 technologies are useful to evaluate claims made by developers, as well as to evaluate market potentials for the United States or specific regions. In this report we show that many new technologies are ready to enter the market place, or are currently under development, demonstrating that the United States is not running out of technologies to improve energy efficiency and economic and environmental performance, and will not run out in the future. The study shows that many of the technologies have important non-energy benefits, ranging from reduced environmental impact to improved productivity. …
Date: March 20, 2001
Creator: Worrell, Ernst; Martin, Nathan; Price, Lynn; Ruth, Michael; Elliott, Neal; Shipley, Anna et al.
System: The UNT Digital Library
How Does a System Respond When Driven Away From Thermal Equilibrium? (open access)

How Does a System Respond When Driven Away From Thermal Equilibrium?

It is widely appreciated that our understanding of non-equilibrium phenomena has not kept pace with its equilibrium counterpart. In recent years, however, consideration of the above question, posed at the microscopic level of statistical mechanics, has yielded some intriguing theoretical results distinguished by two common features. First, they remain valid far from equilibrium, that is, even if the system is disturbed violently from its initial equilibrium state. Second, they incorporate information about the history of the system over some span of time: effectively, these are statistical predictions about what we would see if we could watch a movie of the system filmed at the atomic level, rather than predictions about individual snapshots. To date, this work has been theoretical, though supplemented with numerical simulations. However, in the current issue of PNAS, Hummer and Szabo [1] show how to combine these theoretical advances with single molecule manipulation experiments, so as to extract useful equilibrium information from non-equilibrium laboratory data. What these authors propose amounts to a novel method of deducing the equilibrium mechanical properties of individual molecules.
Date: March 1, 2001
Creator: Jarzynski, C.
System: The UNT Digital Library
High Luminosity Polarized Proton Collisions at RHIC (open access)

High Luminosity Polarized Proton Collisions at RHIC

The Brookhaven Relativistic Heavy Ion Collider (RHIC) provides the unique opportunity to collide polarized proton beams at a center-of-mass energy of up to 500 GeV and luminosities of up to 2 x 10{sup 32} cm{sup {minus}2} s{sup {minus}1}. Such high luminosity and high energy polarized proton collisions will open up the possibility of studying spin effects in hard processes. However, the acceleration of polarized beams in circular accelerators is complicated by the numerous depolarizing spin resonances. Using a partial Siberian snake and a rf dipole that ensure stable adiabatic spin motion during acceleration has made it possible to accelerate polarized protons to 25 GeV at the Brookhaven AGS. After successful operation of RHIC with gold beams polarized protons from the AGS have been successfully injected into RHIC and accelerated using a full Siberian snakes built from four superconducting helical dipoles. A new high energy proton polarimeter was also successfully commissioned. Operation with two snakes per RHIC ring is planned for next year.
Date: March 26, 2001
Creator: Roser, T.
System: The UNT Digital Library
Equilibrium and Nonequilibrium Foundations of Free Energy Computational Methods (open access)

Equilibrium and Nonequilibrium Foundations of Free Energy Computational Methods

Statistical mechanics provides a rigorous framework for the numerical estimation of free energy differences in complex systems such as biomolecules. This paper presents a brief review of the statistical mechanical identities underlying a number of techniques for computing free energy differences. Both equilibrium and nonequilibrium methods are covered.
Date: March 1, 2001
Creator: Jarzynski, C.
System: The UNT Digital Library
Towards the Standardization of a MATLAB-Based Control Systems Laboratory Experience for Undergraduate Students (open access)

Towards the Standardization of a MATLAB-Based Control Systems Laboratory Experience for Undergraduate Students

This paper seeks to begin a discussion with regard to developing standardized Computer Aided Control System Design (CACSD) tools that are typically utilized in an undergraduate controls laboratory. The advocated CACSD design tools are based on the popular, commercially available MATLAB environment, the Simulink toolbox, and the Real-Time Workshop toolbox. The primary advantages of the proposed approach are as follows: (1) the required computer hardware is low cost, (2) commercially available plants from different manufacturers can be supported under the same CACSD environment with no hardware modifications, (3) both the Windows and Linux operating systems can be supported via the MATLAB based Real-Time Windows Target and the Quality Real Time Systems (QRTS) based Real-Time Linux Target, and (4) the Simulink block diagram approach can be utilized to prototype control strategies; thereby, eliminating the need for low level programming skills. It is believed that the above advantages related to standardization of the CACSD design tools will facilitate: (1) the sharing of laboratory resources within each university (i.e., between departments) and (2) the development of Internet laboratory experiences for students (i.e., between universities).
Date: March 15, 2001
Creator: Dixon, W.E.
System: The UNT Digital Library
A BENCHMARK PROGRAM FOR EVALUATION OF METHODS FOR COMPUTING SEISMIC RESPONSE OF COUPLED BUILDING-PIPING/EQUIPMENT WITH NON-CLASSICAL DAMPING. (open access)

A BENCHMARK PROGRAM FOR EVALUATION OF METHODS FOR COMPUTING SEISMIC RESPONSE OF COUPLED BUILDING-PIPING/EQUIPMENT WITH NON-CLASSICAL DAMPING.

Under the auspices of the US Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) developed a comprehensive program to evaluate state-of-the-art methods and computer programs for seismic analysis of typical coupled nuclear power plant (NPP) systems with nonclassical damping. In this program, four benchmark models of coupled building-piping/equipment systems with different damping characteristics were analyzed for a suite of earthquakes by program participants applying their uniquely developed methods and computer programs. This paper presents the results of their analyses, and their comparison to the benchmark solutions generated by BNL using time domain direct integration methods. The participant's analysis results established using complex modal time history methods showed good comparison with the BNL solutions, while the analyses produced with either complex-mode response spectrum methods or classical normal-mode response spectrum method, in general, produced more conservative results, when averaged over a suite of earthquakes. However, when coupling due to damping is significant, complex-mode response spectrum methods performed better than the classical normal-mode response spectrum method. Furthermore, as part of the program objectives, a parametric assessment is also presented in this paper, aimed at evaluation of the applicability of various analysis methods to problems with different dynamic characteristics unique to coupled NPP systems. …
Date: March 22, 2001
Creator: Xu, J.; Degrassi, G. & Chokshi, N.
System: The UNT Digital Library
Sub-Microsecond Decay Time Phosphors for Pressure Sensitive Paint Applications (open access)

Sub-Microsecond Decay Time Phosphors for Pressure Sensitive Paint Applications

The results suggest that garnet phosphors can be engineered to function thermographically over desired temperature ranges by adjusting gallium content. Substituting gadolinium for the yttrium in the host matrix also has an effect but it is not as large. A silicate phosphor showed the greatest temperature dependence though it could not be excited to fluoresce by a blue LED. All the garnet phosphors could be excited with such a blue source. Two phosphors tested showed an increase in intensity with temperature. Other garnet and silicate materials as mentioned above will be tested in the future. In addition, some perovskite phosphors, such as GdAlO{sub 3}:Ce, will also be investigated.
Date: March 22, 2001
Creator: Allison, S.W.
System: The UNT Digital Library
Observation of Au + Au --> Au + Au + rho(0) and Au + Au --> Au* + Au* + rho(0) with STAR (open access)

Observation of Au + Au --> Au + Au + rho(0) and Au + Au --> Au* + Au* + rho(0) with STAR

We report the first observation of the reactions Au + Au {yields} Au + Au + {rho}{sup 0} and Au + Au {yields} Au* + Au* + {rho}{sup 0} with the STAR detector. The {rho} are produced at small perpendicular momentum, as expected if they couple coherently to both nuclei. We discuss models of vector meson production and the correlation with nuclear breakup, and present a fundamental test of quantum mechanics that is possible with the system.
Date: March 10, 2001
Creator: Klein, Spencer
System: The UNT Digital Library
Cathodic Reduction of Passive Films on Iron in Borate and Phosphate Buffer Ph 8.4: Different Mechanisms Revealed by in Situ Techniques. (open access)

Cathodic Reduction of Passive Films on Iron in Borate and Phosphate Buffer Ph 8.4: Different Mechanisms Revealed by in Situ Techniques.

The electrochemical behavior of passive Fe and thin, sputter-deposited films of Fe{sub 2}O{sub 3} was studied in borate and phosphate buffer pH 8.4 solutions. Cyclic voltammograms and in situ light absorption measurements--which enable the monitoring of the oxide film thickness--indicate a similar behavior of the Fe electrode in both pH 8.4 solution, especially a presence of a oxide-free surface at low cathodic potentials. However, X-ray absorption near edge structure (XANES) studies--which allow a simultaneous monitoring of changes in the samples' average valency and thickness - reveal that the reactions taking place during reduction of the passive film on iron are completely different for the two electrolytes. In borate buffer (pH 8.4), reduction leads to a complete dissolution of the passive film and the end product of reduction is soluble Fe(2+). In phosphate buffer (pH 8.4), there is no dissolution in a direct step to low cathodic potentials, but the resulting reduction product is metallic iron. Hence, the formation of the bare oxide-free metal surface at cathodic potentials takes place by different mechanisms in the two pH 8.4 solutions, depending on the type of anion present in the solution.
Date: March 25, 2001
Creator: Schmuki, P.; Virtanen, S. & Isaacs, H. S.
System: The UNT Digital Library
CDF Run I B physics results (open access)

CDF Run I B physics results

The CDF Run I B physics program has been very successful, making numerous measurements over a wide variety of B physics topics. Measurements have included masses and lifetimes; discovery of the B{sub c}; B{sub s} {r_arrow} J/{psi}{phi} polarization; B{sup 0} {leftrightarrow} {bar B}{sup 0} mixing; sin (2{beta}); and rare decay limits. Recent results include a search for {Lambda}{sub b} {r_arrow} {Lambda}{gamma} and a study of B{sup 0} {r_arrow} J/{psi}K(*){sup 0} {pi}{sup +}{pi}{sup {minus}} decays. The tools and experience developed during Run I are quite valuable as CDF enters Run II.
Date: March 8, 2001
Creator: Bailey, S.
System: The UNT Digital Library
Next-Generation Numerical Modeling: Incorporating Elasticity, Anisotropy and Attenuation (open access)

Next-Generation Numerical Modeling: Incorporating Elasticity, Anisotropy and Attenuation

A new effort has been initiated between the Department of Energy (DOE) and the Society of Exploration Geophysicists (SEG) to investigate what features the next generation of numerical seismic models should contain that will best address current technical problems encountered during exploration in increasingly complex geologies. This collaborative work is focused on designing and building these new models, generating synthetic seismic data through simulated surveys of various geometries, and using these data to test and validate new and improved seismic imaging algorithms. The new models will be both 2- and 3-dimensional and will include complex velocity structures as well as anisotropy and attenuation. Considerable attention is being focused on multi-component acoustic and elastic effects because it is now widely recognized that converted phases could play a vital role in improving the quality of seismic images. An existing, validated 3-D elastic modeling code is being used to generate the synthetic data. Preliminary elastic modeling results using this code are presented here along with a description of the proposed new models that will be built and tested.
Date: March 1, 2001
Creator: Larsen, S.
System: The UNT Digital Library
The Potential for Dating Groundwater Using Radiogenic Noble Gases (open access)

The Potential for Dating Groundwater Using Radiogenic Noble Gases

The accumulation in groundwater of products from the radioactive decay of elements naturally found in rocks offers a potential for measuring the time that the groundwater has been contact with the rock. This dating method has an advantage over using decay products from the atmosphere in that the amount of decay products increases with age rather than decreases. However, different decay products accumulate at different rates and, thus, have a different potential usefulness in age determinations. The most useful decay product is helium, produced from uranium and thorium. The use of Ar-40 produced from potassium is limited because Ar-40 is abundant in meteoric water. Neon, xenon and krypton are useful with great difficulty because they are produced in extremely small quantities. In general, the potential for error increases when a long time is required to produce a small quantity of the dating nuclide.
Date: March 23, 2001
Creator: Cornman, W.R.
System: The UNT Digital Library
Solid-State Electrochemical Sensors for Automotive Applications (open access)

Solid-State Electrochemical Sensors for Automotive Applications

None
Date: March 1, 2001
Creator: Mukundan, R.; Brosha, E. & Garzon, F.
System: The UNT Digital Library
The Clean Air Act and Renewable Energy: Opportunities, Barriers, and Options (open access)

The Clean Air Act and Renewable Energy: Opportunities, Barriers, and Options

This paper examines the opportunities, obstacles, and potential options to promote renewable energy under the CAA and related programs. It deals, in sequence, with the regulation of SO2, NOx, regional haze/particulate matter, and CO2. For each pollutant, the paper discusses the opportunities, barriers, and options for boosting renewables under the CAA. It concludes by comparing the options discussed. The paper is based on a project on environmental regulation and renewable energy in electricity generation conducted by the National Renewable Energy Laboratory for the Office of Power Technologies, Office of Energy Efficiency and Renewable Energy, US Department of Energy.
Date: March 1, 2001
Creator: Wooley, D.R. (Young, Sommer, Ward, Ritzenberg, Wooley, Baker and Moore, LLC); Morss, E.M. (Young, Sommer, Ward, Ritzenberg, Wooley, Baker and Moore, LLC) & Fang, J.M. (National Renewable Energy Laboratory)
System: The UNT Digital Library
Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires, and Soot Generation (open access)

Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires, and Soot Generation

Piston-wetting effects are investigated in an optical direct-injection spark-ignition (DISI) engine. Fuel spray impingement on the piston leads to the formation of fuel films, which are visualized with a laser-induced fluorescence (LIF) imaging technique. Oxygen quenching is found to reduce the fluorescence yield from liquid gasoline. Fuel films that exist during combustion of the premixed charge ignite to create piston-top pool fires. These fires are characterized using direct flame imaging. Soot produced by the pool fires is imaged using laser elastic scattering and is found to persist throughout the exhaust stroke, implying that piston-top pool fires are a likely source of engine-out particulate emissions for DISI engines.
Date: March 5, 2001
Creator: Stevens, Eric & Steeper, Richard
System: The UNT Digital Library
STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS. (open access)

STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.
Date: March 22, 2001
Creator: Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P. et al.
System: The UNT Digital Library
DYNAMIC DEFORMATION AND DAMAGE IN CAST GAMMA-TiAl DURING TYALOR CYLINDER IMPACT: EXPERIMENTS AND MODEL VALIDATION (open access)

DYNAMIC DEFORMATION AND DAMAGE IN CAST GAMMA-TiAl DURING TYALOR CYLINDER IMPACT: EXPERIMENTS AND MODEL VALIDATION

The dynamic deformation, damage evolution, and cracking in two cast gamma titanium aluminide alloys has been investigated experimentally and theoretically. The purpose of this study was to create and validate experimentally a finite-element model of the high speed impact of a cylindrical {gamma}-TiAl projectile into a steel block in order to evaluate the accuracy of {gamma} constitutive properties used in FEA simulations. In this paper the damage evolution, cracking, and validation of the constitutive response of Ti-48-2-2 and WMS cast gamma alloys is discussed. The utility of validating the high-rate impact behavior of engineering aerospace materials using Taylor cylinder impact testing is detailed.
Date: March 1, 2001
Creator: GRAY, G. & AL, ET
System: The UNT Digital Library
SOFTWARE TOOLS THAT ADDRESS HAZARDOUS MATERIAL ISSUES DURING NUCLEAR FACILITY D and D (open access)

SOFTWARE TOOLS THAT ADDRESS HAZARDOUS MATERIAL ISSUES DURING NUCLEAR FACILITY D and D

The 49-year-old Chemistry and Metallurgy Research (CMR) Facility is where analytical chemistry and metallurgical studies on samples of plutonium and nuclear materials are conduct in support of the Department of Energy's nuclear weapons program. The CMR Facility is expected to be decontaminated and decommissioned (D and D) over the next ten to twenty years. Over the decades, several hazardous material issues have developed that need to be address. Unstable chemicals must be properly reassigned or disposed of from the workspace during D and D operation. Materials that have critical effects that are primarily chronic in nature, carcinogens, reproductive toxin, and materials that exhibit high chronic toxicity, have unique decontamination requirements, including the decontrolling of areas where these chemicals were used. Certain types of equipment and materials that contain mercury, asbestos, lead, and polychlorinated biphenyls have special provisions that must be addressed. Utilization of commercially available software programs for addressing hazardous material issues during D and D operations such as legacy chemicals and documentation are presented. These user-friendly programs eliminate part of the tediousness associated with the complex requirements of legacy hazardous materials. A key element of this approach is having a program that inventories and tracks all hazardous materials. Without …
Date: March 1, 2001
Creator: COURNOYER, M. & GRUNDEMANN, R.
System: The UNT Digital Library
Event by event fluctuations and the QGP (open access)

Event by event fluctuations and the QGP

We discuss the physics underlying event-by-event fluctuations in relativistic heavy ion collisions. We will emphasize how the fluctuations of particle ratios can be utilized to explore the properties of the matter created in these collisions. In particular, we will argue that the fluctuations of the ratio of positively over negatively charged particles may serve as a unique signature for the Quark Gluon Plasma.
Date: March 30, 2001
Creator: Koch, V.; Bleicher, M. & Jeon, S.
System: The UNT Digital Library
DSDP3: dual scaling algorithm for general positive semidefinite programming. (open access)

DSDP3: dual scaling algorithm for general positive semidefinite programming.

We implement a dual scaling algorithm for positive semidefinite programming to handle a broader class of problems than could be solved with previous implementations of the algorithm. With appropriate representations of constraint matrices, we can solve general semidefinite programs and still exploit the structure of large-scale combinatorial optimization problems. Computational results show that our preliminary implementation is competitive with primal-dual solvers on many problems requiring moderate precision in the solution and is superior to primal-dual solvers for several types of problems.
Date: March 19, 2001
Creator: Benson, S.J. & Ye, Y.
System: The UNT Digital Library
Primary ion sources for EBIS (open access)

Primary ion sources for EBIS

This paper gives an introduction into the topic of primary ion sources that can be used to feed ions of normally solid elements into EBIS devices. Starting with a set of typical requirements for primary ion sources, some major types of ion generators are discussed first, with emphasis on their working principles rather than trying to give a fully representative listing of used and proposed generators. Beam-transport issues between primary ion source and EBIS are then examined, and generic characteristics of suitable beam-formation and transport systems are explained.
Date: March 21, 2001
Creator: Keller, R.
System: The UNT Digital Library
Search for charged Higgs bosons in decays of pair-produced top quarks at D0 (open access)

Search for charged Higgs bosons in decays of pair-produced top quarks at D0

The authors present a search for t {r_arrow} bH{sup +} in t{bar t} candidate events at D0 based on two methods. The first seeks a deficit in signal relative to expectations from the standard model (SM). Such a deficit would imply the presence of a non-SM decay of the top quark. This search involves the full data sample of {approx} 110 pb{sup {minus}1} of p{bar p} collisions at {radical}s = 1.8 TeV, collected with the D0 detector. The second method looks for charged Higgs decays to {tau} leptons (and associated neutrinos), and is based on a 62 pb{sup {minus}1} subset of the aforementioned data sample.
Date: March 2, 2001
Creator: Gutierrez, P.
System: The UNT Digital Library
ESTIMATION OF RELATIVISTIC ACCRETION DISK PARAMETERS FROM IRON LINE EMISSION (open access)

ESTIMATION OF RELATIVISTIC ACCRETION DISK PARAMETERS FROM IRON LINE EMISSION

The observed iron K{alpha} fluorescence lines in Seyfert I galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the emission. Here we present an analysis of the geometrical and kinematic properties of the disk based on the extreme frequency shifts of a line profile as determined by measurable flux in both the red and blue wings. The edges of the line are insensitive to the distribution of the X-ray flux over the disk, and hence provide a robust alternative to profile fitting of disk parameters. Our approach yields new, strong bounds on the inclination angle of the disk and the location of the emitting region. We apply our method to interpret observational data from MCG-6-30-15 and find that the commonly assumed inclination 30{degree} for the accretion disk in MCG-6-30-15 is inconsistent with the position of the blue edge of the line at a 3{sigma} level. A thick turbulent disk model or the presence of highly ionized iron may reconcile the bounds on inclination from the line edges with the full line profile fits based on simple, geometrically thin disk models. The bounds on the innermost radius of disk emission indicate that the …
Date: March 1, 2001
Creator: PARIEV, V.; BROMLEY, B. & MILLER, W.
System: The UNT Digital Library
Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds (open access)

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds

The purposes of this work were to: (1) develop preliminary operating data such as expected concentration endpoints for flow sheet development and evaporator design, and (2) examine the regulatory off-gas emission impacts from the evaporation of relatively organic-rich Hanford Tank 241-AN-107 Envelope C waste simulant containing 14 volatile, semi-volatile and pesticide organic compounds potentially present in actual Hanford RPP waste.
Date: March 28, 2001
Creator: Saito, H.H.
System: The UNT Digital Library