The Advanced Petroleum-Based Fuels Program DECSE and APBF Overview (open access)

The Advanced Petroleum-Based Fuels Program DECSE and APBF Overview

The following topics are summarized: Role of fuel blends in controlling engine-out emissions; Effect of fuels and lubricants on emission control devices; and Effect of fuels and lubricants on vehicle emissions and operations.
Date: April 11, 2000
Creator: unknown
System: The UNT Digital Library
Aggregation quenching in thin films of meh-ppv studied by near-field scanning optical microscopy and spectroscopy (open access)

Aggregation quenching in thin films of meh-ppv studied by near-field scanning optical microscopy and spectroscopy

Aggregates in thin films of conjugated polymers form excimer states and significantly reduce the photo- and electroluminescence efficiency in devices produced from these materials. We have studied the aggregate formation in thin films of MEH-PPV by near-field scanning optical microscopy and spectroscopy. Local photoluminescence spectroscopy and photo-bleaching experiments have been used to show that thin films of MEH-PPV are homogeneously aggregated and do not form aggregated domains.
Date: April 11, 2000
Creator: Huser, T & Yan, M
System: The UNT Digital Library
Analysis of Forcing, Response, and Feedbacks in a Paleoclimate Modeling Experiment (open access)

Analysis of Forcing, Response, and Feedbacks in a Paleoclimate Modeling Experiment

It is often argued that paleoclimate studies are necessary to determine whether climate models and their predictions of future climate change can be trusted. An overall measure of the sensitivity of global mean surface temperature to a given radiative perturbation is provided by the global climate sensitivity parameter. In climate model experiments, this parameter appears to be moderately independent of the cause of the perturbation [see, for example, Hansen et al. (1997) and Hewitt and Mitchell (1997)], but it may differ from one model to the next by as much as a factor of three (IPCC, 1995). Moreover, there are some scientists who claim that all models are much more sensitive than the climate system itself (Lindzen, 1997). Thus it would be valuable to determine which models (if any) are consistent with the paleoclimate record and what factors are responsible for model differences in sensitivity. In an analysis of the Paleoclimate Modeling Intercomparison Project (PMIP) simulations of the Last Glacial Maximum (LGM) of 21,000 years ago, we have calculated how the ''forcing'' and feedbacks determine the climatic response. In the PMIP context, the ice sheet distribution is prescribed and the resulting increase in planetary albedo is the most important ''forcing'' …
Date: April 11, 2001
Creator: Taylor, K E; Hewitt, C D; Braconnot, P; Broccoli, A J; Doutriaux, C & Mitchell, J F B
System: The UNT Digital Library
Analytical Review (open access)

Analytical Review

ANL Performs Independent Review for DOE on the following topics: (1) Systematic analysis--Depends on question asked; (2) Compare technologies and pathways--Examples: (a) fuels, power plant technologies, vehicle materials; (b) Total lifecycle analysis reveals national and global impacts; and (3) Direction of R&D to most fruitful areas.
Date: April 11, 2000
Creator: Stodolsky, Frank
System: The UNT Digital Library
An Automated Implementation of On-shell Methods for One-Loop Amplitudes (open access)

An Automated Implementation of On-shell Methods for One-Loop Amplitudes

None
Date: April 11, 2008
Creator: Berger, C.F.; Bern, Z.; Dixon, L.J.; Febres Cordero, F.; Forde, D.; Ita, H. et al.
System: The UNT Digital Library
Betatron radiation from density tailored plasmas (open access)

Betatron radiation from density tailored plasmas

In laser wakefield accelerators, electron motion is driven by intense forces that depend on the plasma density. Transverse oscillations in the accelerated electron orbits produce betatron radiation. The electron motion and the resulting betatron radiation spectrum can therefore be controlled by shaping the plasma density along the orbit of the electrons. Here, a method based on the use of a plasma with a longitudinal density variation (density depression or step) is proposed to increase the transverse oscillation amplitude and the energy of the electrons accelerated in a wakefield cavity. For fixed laser parameters, by appropriately tailoring the plasma profile, the betatron radiation emitted by these electrons is significantly increased in both flux and energy.
Date: April 11, 2009
Creator: Ta Phuoc, Kim; Esarey, E.; Leurent, V.; Cormier-Michel, E.; Geddes, C. G. R.; Schroeder, C. B. et al.
System: The UNT Digital Library
A case study in modeling company policy documents as a source of requirements (open access)

A case study in modeling company policy documents as a source of requirements

This paper describes an approach that was developed to produce structured models that graphically reflect the requirements contained within a text document. The document used in this research is a draft policy document governing business in a research and development environment. In this paper, the authors present a basic understanding of why this approach is needed, the techniques developed, lessons learned during modeling and analysis, and recommendations for future investigation. The modeling method applied on the policy document was developed as an extension to entity relationship (ER) diagrams, which built in some structural information typically associated with object-oriented techniques. This approach afforded some structure as an analysis tool, while remaining flexible enough to be used with the text document. It provided a visual representation that allowed further analysis and layering of the model to be done.
Date: April 11, 2000
Creator: CRUMPTON,KATHLEEN MARIE; GONZALES,REGINA M. & TRAUTH,SHARON L.
System: The UNT Digital Library
Combustion Effects in Confined Explosions (open access)

Combustion Effects in Confined Explosions

None
Date: April 11, 2008
Creator: Kuhl, A L & Reichenbach, H
System: The UNT Digital Library
Comparison of the electrochemical properties of several commercial graphites with a templated disordered carbon (open access)

Comparison of the electrochemical properties of several commercial graphites with a templated disordered carbon

A templated carbon was prepared by the pyrolysis of pyrene impregnated into pillared clay (PILC). The electrochemical performance of this was evaluated with the goal of using this material as an anode in Li-ion cells. The reversible capacity was measured as a function of C rate and the cycling characteristics were determined for various intercalation protocols. The performance of this material was compared to that of several commercial graphites tested under the same conditions. The PILC carbon shows great promise as a Li-ion anode if the fade and first-cycle losses can be controlled.
Date: April 11, 2000
Creator: Guidotti, R. A.; Reinhardt, F. W. & Sandi, G.
System: The UNT Digital Library
Continuing Science and Technology for the Office of Civilian Radioactive Waste Management (open access)

Continuing Science and Technology for the Office of Civilian Radioactive Waste Management

None
Date: April 11, 2005
Creator: Finch, R. J.
System: The UNT Digital Library
Dark Energy in the Dark Ages (open access)

Dark Energy in the Dark Ages

Non-negligible dark energy density at high redshifts would indicate dark energy physics distinct from a cosmological constant or"reasonable'" canonical scalar fields. Such dark energy can be constrained tightly through investigation of the growth of structure, with limits of<~;;2percent of total energy density at z>> 1 for many models. Intermediate dark energy can have effects distinct from its energy density; the dark ages acceleration can be constrained to last less than 5percent of a Hubble e-fold time, exacerbating the coincidence problem. Both the total linear growth, or equivalently sigma 8, and the shape and evolution of the nonlinear mass power spectrum for z<2 (using the Linder-White nonlinear mapping prescription) provide important windows. Probes of growth, such as weak gravitational lensing, can interact with supernovae and CMB distance measurements to scan dark energy behavior over the entire range z=0-1100.
Date: April 11, 2006
Creator: Linder, Eric V.
System: The UNT Digital Library
Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX (open access)

Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX

None
Date: April 11, 2008
Creator: Bradac, Marusa; Schrabback, Tim; Erben, Thomas; McCourt, Michael; Million, Evan; Mantz, Adam et al.
System: The UNT Digital Library
A database prototype has been developed to help understand costs in photovoltaic systems (open access)

A database prototype has been developed to help understand costs in photovoltaic systems

High photovoltaic (PV) system costs hinder market growth. An approach to studying these costs has been developed using a database containing system, component and maintenance information. This data, which is both technical and non-technical in nature, is to be used to identify trends related to costs. A pilot database exists at this time and work is continuing. The results of this work may be used by the data owners to improve their operations with the goal of sharing non-attributable information with the public and industry at large. The published objectives of the DOE PV program are to accelerate the development of PV as a national and global energy option, as well as ensure US technology and global market leadership. The approach to supporting these objectives is to understand what drives costs in PV applications. This paper and poster session describe work-in-progress in the form of a database that will help identify costs in PV systems. In an effort to address DOE's Five-Year PV Milestones, a program was established in the summer of 1999 to study system costs in three PV applications--solar home lighting, water pumping, and grid-tied systems. This work began with a RFQ requesting data from these types of …
Date: April 11, 2000
Creator: MOORE,LARRY M.
System: The UNT Digital Library
Designing Remote Monitoring Systems for Long Term Maintenance and Reliability (open access)

Designing Remote Monitoring Systems for Long Term Maintenance and Reliability

As part of the effort to modernize safeguards equipment, the IAEA is continuing to acquire and install equipment for upgrading obsolete surveillance systems with digital technology; and providing remote-monitoring capabilities where and when economically justified. Remote monitoring is expected to reduce inspection effort, particularly at storage facilities and reactor sites. Remote monitoring technology will not only involve surveillance, but will also include seals, sensors, and other unattended measurement equipment. LLNL's experience with the Argus Security System offers lessons for the design, deployment, and maintenance of remote monitoring systems. Argus is an integrated security system for protection of high-consequence U.S. Government assets, including nuclear materials. Argus provides secure transmission of sensor data, administrative data, and video information to support intrusion detection and access control functions. LLNL developed and deployed the Argus system on its own site in 1988. Since that time LLNL has installed, maintained, and upgraded Argus systems at several Department of Energy and Department of Defense sites in the US as well as at the original LLNL site. Argus has provided high levels of reliability and integrity, as well as reducing overall lifecycle cost through incremental improvements to hardware and software. This philosophy permits expansion of functional capability, hardware …
Date: April 11, 2001
Creator: Davis, G. E.; Johnson, G. L.; Schrader, F. D.; Stone, M. A. & Wilson, E. F.
System: The UNT Digital Library
Detection of Materials of Interest to Non-Proliferation: A Novel Approach (open access)

Detection of Materials of Interest to Non-Proliferation: A Novel Approach

We propose the development of a novel detector that can locate and identify materials of interest to Nuclear Arms Non Proliferation. The device will combine nuclear acoustic resonance (NAR) with superconducting quantum interference device (SQUID) widely used in nuclear magnetic resonance (NMR), geophysics, nondestructive evaluations, and biomagnetism, to name only few. NAR works like NMR. Thus resonant absorption (of applied ultrasonic energy) by a nuclear spin system occurs when the ultrasonic frequency is equal to the appropriate frequency separations between the magnetic nuclear energy levels. Ultrasonic energy couples to the nuclear spin system via spin-phonon interaction. The resulting nuclear acoustic resonance can be detected via the changes in (a) ultrasonic attenuation, (b) ultrasonic velocity, (c) material magnetization, (d) or nuclear magnetic susceptibility, all of which carries ''intrinsic and unique signatures'' of the material under investigation. The device's sensitivity and penetration depth (into metals) will be enhanced by incorporating SQUID technology into the design. We will present the details of interaction physics and outline a plan of action needed to successfully transform the concepts into a practical detector.
Date: April 11, 2002
Creator: Ze, F; Tittmann, B R & Lehahan, P M
System: The UNT Digital Library
Developing a Process for Commercial Silica Production from Geothermal Brines (open access)

Developing a Process for Commercial Silica Production from Geothermal Brines

Useful mineral by-products can be produced from geothermal brines. Although silica has many commercial uses, problems remain in producing a marketable product. We are conducting laboratory and modeling studies aimed at optimizing for rubber additive use, the properties of silica precipitates from Salton Sea and Coso-like geothermal fluids, Our goal is to develop a robust technique for producing silicas that have desirable physical and chemical properties for commercial use, while developing a generic understanding of silica precipitation that will allow extraction to be extended to additional fluid types, and to be easily modified to produce new types of marketable silica. Our experiments start with an acidified geothermal fluid similar to those treated by pH modification technology. Silica precipitation is induced by adding base and/or adding Mg or Ca salts to affect the nature of the precipitate. For the analog Salton Sea fluids, adding base alone caused silica to precipitate fairly rapidly. To date, we have characterized precipitates from experiments in which the final pH varied from 4 to 8, where NaOH and Na{sub 2}C0{sub 3} were added as bases, and CaCl{sub 2} and MgCl{sub 2} were added as salts. SEM photos of the silica precipitates from the Salton Sea and …
Date: April 11, 2001
Creator: Bourcier, W; Martin, S; Viani, B & Bruton, C
System: The UNT Digital Library
Development of High Power Lasers for Materials Interactions (open access)

Development of High Power Lasers for Materials Interactions

The Lawrence Livermore National Laboratory (LLNL) has a long history of developing high power lasers for use in basic science and applications. The Laser Science and Technology Program (LS&T) at LLNL supports advanced lasers and optics development both for the National Ignition Facility (NIF) as well as for high power lasers and optics technology for a broader range of government, military and industrial applications. The NIF laser is currently under construction with the first of the 192 beamlines being activated. When finished NIF will have an output energy of 2 MJ at 351 nm. This system will be used for studies of high energy density physics, equation of state and inertial confinement fusion. It is now generally acknowledged that the future of laser missile defense lies with solid state lasers. The leading laser technology for theater missile defense is under development within the LS&T and funded by the US Army SMDC. This high average power technology is based on a solid state laser operated in a heat capacity mode. In the concept the heat producing lasing cycle is separated in time from the cooling cycle thus reducing thermal gradients and allowing significantly greater average output power. Under the current program, …
Date: April 11, 2003
Creator: Hackel, L A
System: The UNT Digital Library
A discussion on life-cycle costs of residential photovoltaic systems (open access)

A discussion on life-cycle costs of residential photovoltaic systems

This paper discusses the characteristics and needed improvements/enhancements required for the expansion of the grid-tied residential power systems market. The purpose of the paper is to help establish a common understanding, between the technical community and the customers of the technology, of value and costs and what is required in the longer term for reaching the full potential of this application.
Date: April 11, 2000
Creator: THOMAS,MICHAEL G. & CAMERON,CHRISTOPHER P.
System: The UNT Digital Library
Evidence for Direct CP Violation from Dalitz-plot analysis of B+ to K+pi+pi- (open access)

Evidence for Direct CP Violation from Dalitz-plot analysis of B+ to K+pi+pi-

None
Date: April 11, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
System: The UNT Digital Library
Experience with parallel optical link for the CDF silicon detector (open access)

Experience with parallel optical link for the CDF silicon detector

The Dense Optical Interface Module (DOIM) is a byte-wide optical link developed for the Run II upgrade of the CDF silicon tracking system [1]. The module consists of a transmitter with a laser-diode array for conversion of digitized detector signals to light outputs, a 22 m optical fiber ribbon cable for light transmission, and a receiver converting the light pulses back to electrical signals. We report on the design feature, characteristics, and radiation tolerance.
Date: April 11, 2003
Creator: Hou, S.
System: The UNT Digital Library
Experimental Determination of Ca-Silicate Dissolution Rates: A Source of Calcium for Geologic CO2 (open access)

Experimental Determination of Ca-Silicate Dissolution Rates: A Source of Calcium for Geologic CO2

The international scientific community recognizes that greenhouse gases have the potential to influence climate, and that potential changes in sea level and weather patterns would be largely deleterious. Because CO{sub 2} is emitted in such large quantities and its atmospheric concentration has been consistently rising throughout the recent past, it is only prudent to focus attention on reducing its emission and on developing strategies for its removal from the atmosphere [1]. A variety of removal methods have been suggested ranging from deep-sea disposal, to recycling to methanol, and to conversion to solid carbonate [2]. Problems appear to remain with all these strategies, and more work is needed to develop an acceptable, efficient method or set of methods. The idea of converting the gas to solid carbonate is particularly appealing, because on a human time scale, this is permanent disposal. The reaction of CO{sub 2} and water with unstable silicate minerals to produce more stable silicates (e.g., clays) and solid carbonates is the natural weathering process which is a dominant part of the long-term global geochemical cycling process (e.g., [3]). The Earth's large deposits of limestone and dolomite (the two primary forms of carbonate rock) represent the Earth's natural response to …
Date: April 11, 2001
Creator: Carroll, S A & Knauss, K G
System: The UNT Digital Library
Finding Bent-double Radio Galaxies: A Case Study in Data Mining (open access)

Finding Bent-double Radio Galaxies: A Case Study in Data Mining

This paper presents our early results in applying data mining techniques to the problem of finding radio-emitting galaxies with a bent-double morphology. In the past, astronomers on the FIRST (Faint Images of the Radio Sky at Twenty-cm) survey have detected such galaxies by first inspecting the radio images visually to identify probable bent-doubles, and then conducting observations to confirm that the galaxy is indeed a bent-double. Our goal is to replace this visual inspection by a semi-automated approach. In this paper, we present a brief overview of data mining, describe the features we use to discriminate bent-doubles from non-bent-doubles, and discuss the challenges faced in defining meaningful features in a robust manner. Our experiments show that data mining, using decision trees, can indeed be a viable alternative to the visual identification of bent-double galaxies.
Date: April 11, 2000
Creator: Fodor, I.K; Cantu-Paz, E.; Kamath, C. & Tang, N.
System: The UNT Digital Library
First Measurements of Pion Correlations by the PHENIX Experiment (open access)

First Measurements of Pion Correlations by the PHENIX Experiment

First identical-pion correlations measured at RHIC energies by PHENIX are presented. Two analyses with separate detectors, systematics, and statistics provide consistent results. The resulting HBT radii are moderately larger than those measured at lower energies. The k{sub t} dependence of the Bertsch-Pratt HBT radii is also similar to previous measures and is consistent with the conjecture of an expanding source.
Date: April 11, 2001
Creator: Johnson, S. C.
System: The UNT Digital Library
Fracture Toughness of 6.4 Mm (0.25 Inch) Arc-Cast Molobdenum and Molybdenum-Tzm Plate at Room Temperature and 300 Degrees C (open access)

Fracture Toughness of 6.4 Mm (0.25 Inch) Arc-Cast Molobdenum and Molybdenum-Tzm Plate at Room Temperature and 300 Degrees C

THE FRACTURE TOUGHNESS OF 6.4 mm (0.25 INCH) LOW CARBON ARC-CAST (LCAC) MOLYBDENUM AND ARC-CAST MOLYBDENUM-TZM ALLOY PLATE WERE MEASURED AT ROOM TEMPERATURE AND 300 DEGREES C USING COMPACT TNESION SPECIMENTS. THE EFFECT OF CRACK PLANE ORIENTATION (LONGITUDINAL VS. TRANSVERSE) AND ANNEALING PRACTICE (STRESS-RELIEVED VS. RECRYSTALLIZED) WERE EVALUATED. DEPENDING UPON THE TEST TEMPERATURE EITHER A STANDARD K[SUB]IC OR A J-INTEGRAL ANALYSIS WAS USED TO OBTAIN THE TOUGHNESS VALUE. AT ROOM TEMPERATURE, REGARDLESS OF ALLOY, ORIENTATION, OR MICROSTURECTURE, FRACTURE TOUGHNESS VALUES BETWEEN 15 AND 22 MPa m{sup 1/2} (14 AND 20 KSI IN{sup 1/2}) WERE MEASURED. THESE K[SUB]IC VALUES WERE CONSISTENT WITH MEASUREMENTS BY THE AUTHORS. INCREASING TEMPERATURE IMPROVES THE TOUGHNESS, DUE TO THE FACT THAT ONE TAKES ADVANTAGE OF THE DUCTIVE-BRITTLE TRANSITION BEHAVIOR OF MOLYBDENUM. AT 300 DEGREES C, THE FRACTURE TOUGHNESS OF RECRYSTALLIZED LCAC AND ARC-CAST TZM MOLYBDENUM WERE ALSO SIMILAR AT APPROXI MATELY 64 MPa m{sup 1/2} (58 KSI IN{sup 1/2}). IN THE STRESS-RELIEVED CONDITION, HOWEVER, THE TOUGHNESS OF ARC-CAST TZM (91 MPa m{sup 1/2}/83 KSI IN{sup 1/2}) WAS HIGHER THAN THAT OF THE LCAC MOLYBDENUM (74 MPa m{sup 1/2}/67 KSI IN{sup 1/2}).
Date: April 11, 2001
Creator: Shields, J. A., Jr.; Lipetzky, P. & Mueller, A. J.
System: The UNT Digital Library