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80 HP PLASMA ASSISTED CATALYST SYSTEM (open access)

80 HP PLASMA ASSISTED CATALYST SYSTEM

The US economy is linked to efficient heavy vehicle transportation and diesel remains the fuel of choice for mass transportation of goods and services. Diesel engines remain the most reliable and cost effective system for commerce. Recent deleterious effects of diesel exhaust on health and environment have led to an urgent need for cost effective technologies that would bring about reduction in NOx and PM. CARB estimates on-road diesel mobile source will contribute almost 50% NOx and 78% PM emissions by 2010. As a result recent Federal and State mandates have been adopted to reduce emissions from diesel exhaust to 1 Gm/bhp.-Hr of NOx and 0.05 Gm/bhp-hr of PM by the year 2007. The 2007 standard is to be achieved in a stepwise manner starting with the standards for 2002 namely 2 Gm/bhp-hr NOx and 0.1 Gm/bhp-hr of PM. 2002 standards are likely to be met by most engine manufacturer by some modified form of exhaust gas recirculation (EGR) system or by employing a sophisticated engine control system. Importance of cost effective technology requirement is further exaggerated by the fact that in recent years diesel engine production have increased dramatically see figure 1 and has out stripped the gasoline engine …
Date: August 5, 2001
Creator: Slone, Ralph
System: The UNT Digital Library
2011 Archaea: Ecology, Metabolism, & Molecular Biology (open access)

2011 Archaea: Ecology, Metabolism, & Molecular Biology

Archaea, one of three major evolutionary lineages of life, are a fascinating and diverse group of microbes with deep roots overlapping those of eukaryotes. The focus of the 'Archaea: Ecology Metabolism & Molecular Biology' GRC conference expands on a number of emerging topics highlighting new paradigms in archaeal metabolism, genome function and systems biology; information processing; evolution and the tree of life; the ecology and diversity of archaea and their viruses. The strength of this conference lies in its ability to couple a field with a rich history in high quality research with new scientific findings in an atmosphere of stimulating exchange. This conference remains an excellent opportunity for younger scientists to interact with world experts in this field.
Date: August 5, 2011
Creator: Stedman, Keneth
System: The UNT Digital Library
2011 Quantum Control of Light & Matter Gordon Research Conference (July 31-August 5, 2011, Mount Holyoke College, South Hadley, MA) (open access)

2011 Quantum Control of Light & Matter Gordon Research Conference (July 31-August 5, 2011, Mount Holyoke College, South Hadley, MA)

Quantum control of light and matter is the quest to steer a physical process to a desirable outcome, employing constructive and destructive interference. Three basic questions address feasibility of quantum control: (1) The problem of controllability, does a control field exist for a preset initial and target state; (2) Synthesis, constructively finding the field that leads to the target; and (3) Optimal Control Theory - optimizing the field that carries out this task. These continue to be the fundamental theoretical questions to be addressed in the conference. How to realize control fields in the laboratory is an ongoing challenge. This task is very diverse viewing the emergence of control scenarios ranging from attoseconds to microseconds. How do the experimental observations reflect on the theoretical framework? The typical arena of quantum control is an open environment where much of the control is indirect. How are control scenarios realized in dissipative open systems? Can new control opportunities emerge? Can one null decoherence effects? An ideal setting for control is ultracold matter. The initial and final state can be defined more precisely. Coherent control unifies many fields of physical science. A lesson learned in one field can reflect on another. Currently quantum information …
Date: August 5, 2011
Creator: Weinacht, Thomas
System: The UNT Digital Library
Accretion onto the first stellar mass black holes (open access)

Accretion onto the first stellar mass black holes

The first stars, forming at redshifts z > 15 in minihalos with M {approx} 10{sup 5-6} M{sub {circle_dot}} may leave behind remnant black holes, which could conceivably have been the 'seeds' for the supermassive black holes observed at z {approx}< 7. We study remnant black hole growth through accretion, including for the first time the radiation emitted due to accretion, with adaptive mesh refinement cosmological radiation-hydrodynamical simulations. The effects of photo-ionization and heating dramatically affect the large-scale inflow, resulting in negligible mass growth. We compare cases with accretion luminosity included and neglected to show that accretion radiation drastically changes the environment within 100 pc of the black hole, increasing gas temperatures by an order of magnitude. Gas densities are reduced and further star formation in the same minihalo is prevented for the two hundred million years we followed. Without radiative feedback included most seed black holes do not gain mass as efficiently as has been hoped for in previous theories, implying that black hole remnants of Pop III stars in minihalos are not likely to be miniquasars. Most importantly, however, our calculations demonstrate that if these black holes are indeed accreting close to the Bondi-Hoyle rate with ten percent radiative …
Date: August 5, 2009
Creator: Alvarez, Marcelo A.; Wise, John H. & Abel, Tom
System: The UNT Digital Library
Accumulator, Transporter, Substrate, and Reactor: Multidimensional Perspectives and Approaches to the Study of Bark (open access)

Accumulator, Transporter, Substrate, and Reactor: Multidimensional Perspectives and Approaches to the Study of Bark

This article is a short review that explores different perspectives and approaches to the study of bark and what they reveal about the myriad ways bark surfaces influence the quality of sub-canopy precipitation.
Date: August 5, 2021
Creator: Ponette-González, Alexandra G.
System: The UNT Digital Library
Accuracy of Density Functional Theory for First-Principles Simulations of Water (open access)

Accuracy of Density Functional Theory for First-Principles Simulations of Water

None
Date: August 5, 2004
Creator: Schwegler, E.; Grossman, J.; Draeger, E.; Allesch, M.; Gygi, F. & Galli, G.
System: The UNT Digital Library
Advanced Techniques for Fourier Transform Wavefront Reconstruction (open access)

Advanced Techniques for Fourier Transform Wavefront Reconstruction

The performance of Fourier transform (FT) reconstructors in large adaptive optics systems with Shack-Hartmann sensors and a deformable mirror is analyzed. FT methods, which are derived for point-based geometries, are adapted for use on the continuous systems. Analysis and simulation show how to compensate for effects such as misalignment of the deformable mirror and wavefront sensor gain. Further filtering methods to reduce noise and improve performance are presented. All these modifications can be implemented at the filtering stage, preserving the speed of FT reconstruction. Simulation of a large system shows how compensated FT methods can have equivalent or better performance to slower vector-matrix-multiply reconstructions.
Date: August 5, 2002
Creator: Poyneer, L A
System: The UNT Digital Library
Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions (open access)

Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions

None
Date: August 5, 2011
Creator: Heuze, O. & Swift, D. C.
System: The UNT Digital Library
Analysis of the DWPF glass pouring system using neural networks (open access)

Analysis of the DWPF glass pouring system using neural networks

Neural networks were used to determine the sensitivity of 39 selected Melter/Melter Off Gas and Melter Feed System process parameters as related to the Defense Waste Processing Facility (DWPF) Melter Pour Spout Pressure during the overall analysis and resolution of the DWPF glass production and pouring issues. Two different commercial neural network software packages were used for this analysis. Models were developed and used to determine the critical parameters which accurately describe the DWPF Pour Spout Pressure. The model created using a low-end software package has a root mean square error of {+-} 0.35 inwc (< 2% of the instrument`s measured range, R{sup 2} = 0.77) with respect to the plant data used to validate and test the model. The model created using a high-end software package has a R{sub 2} = 0.97 with respect to the plant data used to validate and test the model. The models developed for this application identified the key process parameters which contribute to the control of the DWPF Melter Pour Spout pressure during glass pouring operations. The relative contribution and ranking of the selected parameters was determined using the modeling software. Neural network computing software was determined to be a cost-effective software tool …
Date: August 5, 1997
Creator: Calloway, T.B., Jr.; Jantzen, Carol M.; Medich, L. & Spennato, N.
System: The UNT Digital Library
ASPARTATE 458 of Human Glutathione Synthetase is Important for Cooperativity and Active Site Structure (open access)

ASPARTATE 458 of Human Glutathione Synthetase is Important for Cooperativity and Active Site Structure

Article discussing ASPARTATE 458 of human glutathione synthetase.
Date: August 5, 2011
Creator: Brown, Teresa R.; Drummond, Michael L.; Barelier, Sarah; Crutchfield, Amanda S.; Dinescu, Adriana; Slavens, Kerri D. et al.
System: The UNT Digital Library
Breakdown During High-Field Bias-Temperature Stress (open access)

Breakdown During High-Field Bias-Temperature Stress

Measurements of dielectric breakdown during high-field electrical stress are typically performed at or near room temperature via constant voltage or current stress methods. In this summary they explore whether useful information might also be obtained by performing current measurements during a temperature ramp at high electric field.
Date: August 5, 1999
Creator: Fleetwood, D. M.; Krisch, K. S. & Sexton, F. W.
System: The UNT Digital Library
cctbx news: Geometry restraints and other new features (open access)

cctbx news: Geometry restraints and other new features

None
Date: August 5, 2004
Creator: Grosse-Kunstleve, Ralf W.; Afonine, Pavel V. & Adams, Paul D.
System: The UNT Digital Library
Cermet Filters To Reduce Diesel Engine Emissions (open access)

Cermet Filters To Reduce Diesel Engine Emissions

Pollution from diesel engines is a significant part of our nation's air-quality problem. Even under the more stringent standards for heavy-duty engines set to take effect in 2004, these engines will continue to emit large amounts of nitrogen oxides and particulate matter, both of which affect public health. To address this problem, the Idaho National Engineering and Environmental Laboratory (INEEL) invented a self-cleaning, high temperature, cermet filter that reduces heavy-duty diesel engine emissions. The main advantage of the INEEL cermet filter, compared to current technology, is its ability to destroy carbon particles and NOx in diesel engine exhaust. As a result, this technology is expected to improve our nation's environmental quality by meeting the need for heavy-duty diesel engine emissions control. This paper describes the cermet filter technology and the initial research and development effort.Diesel engines currently emit soot and NOx that pollute our air. It is expected that the U.S. Environmental Protection Agency (EPA) will begin tightening the regulatory requirements to control these emissions. The INEEL's self-cleaning, high temperature cermet filter provides a technology to clean heavy-duty diesel engine emissions. Under high engine exhaust temperatures, the cermet filter simultaneously removes carbon particles and NOx from the exhaust gas. The …
Date: August 5, 2001
Creator: Kong, Peter
System: The UNT Digital Library
Chamber wall response to target implosion in inertial fusion reactors : new and critical assessments. (open access)

Chamber wall response to target implosion in inertial fusion reactors : new and critical assessments.

The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include use of solid bare walls, gas-filled cavities, and liquid walls/jets. Detailed models have been developed for reflected laser light, emitted photons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The hydrodynamic response of gas filled cavities and photon radiation transport of the deposited energy has been calculated by means of new and advanced numerical techniques. Fragmentation models of liquid jets as a result of the deposited energy have also been developed, and the impact on chamber clearing dynamics has been evaluated. The focus of this study is to critically assess the reliability and the dynamic response of chamber walls in various proposed protection methods for IFE systems. Of particular concern is the effect on …
Date: August 5, 2002
Creator: Hassanein, A. & Morozov, V.
System: The UNT Digital Library
CHARACTERIZATION OF VITRIFIED SAVANNAH RIVER SITE SB4 WASTE SURROGATE PRODUCED IN COLD CRUCIBLE (open access)

CHARACTERIZATION OF VITRIFIED SAVANNAH RIVER SITE SB4 WASTE SURROGATE PRODUCED IN COLD CRUCIBLE

Savannah River Site (SRS) sludge batch 4 (SB4) waste surrogate with high aluminum and iron content was vitrified with commercially available Frit 503-R4 (8 wt.% Li{sub 2}O, 16 wt.% B2O3, 76 wt.% SiO{sub 2}) by cold crucible inductive melting using lab- (56 mm inner diameter), bench- (236 mm) and large-scale (418 mm) cold crucible. The waste loading ranged between 40 and 60 wt.%. The vitrified products obtained in the lab-scale cold crucible were nearly amorphous with traces of unreacted quartz in the product with 40 wt.% waste loading and traces of spinel phase in the product with 50 wt.% waste loading. The glassy products obtained in the bench-scale cold crucible are composed of major vitreous and minor iron-rich spinel phase whose content at {approx}60 wt.% waste loading may achieve {approx}10 vol.%. The vitrified waste obtained in the large-scale cold crucible was also composed of major vitreous and minor spinel structure phases. No nepheline phase has been found. Average degree of crystallinity was estimated to be {approx}12 vol.%. Anionic motif of the glass network is built from rather short metasilicate chains and boron-oxygen constituent based on boron-oxygen triangular units.
Date: August 5, 2008
Creator: Marra, J
System: The UNT Digital Library
CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS (open access)

CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS

Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have already been identified but have not been implemented, (b) what other root causes may be involved, and (c) what new corrective actions should be taken to eliminate these newly identified root causes.
Date: August 5, 2008
Creator: Simmons, F
System: The UNT Digital Library
The Chemistry of the Thermal DeNOx Process: A Review of the Technology's Possible Application to control of NOx from Diesel Engines (open access)

The Chemistry of the Thermal DeNOx Process: A Review of the Technology's Possible Application to control of NOx from Diesel Engines

This paper presents a review of the Thermal DeNOx process with respect to its application to control of NOx emissions from diesel engines. The chemistry of the process is discussed first in empirical and then theoretical terms. Based on this discussion the possibilities of applying the process to controlling NOx emissions from diesel engines is considered. Two options are examined, modifying the requirements of the chemistry of the Thermal DeNOx process to suit the conditions provided by diesel engines and modifying the engines to provide the conditions required by the process chemistry. While the former examination did not reveal any promising opportunities, the latter did. Turbocharged diesel engine systems in which the turbocharger is a net producer of power seem capable of providing the conditions necessary for NOx reduction via the Thermal DeNOx reaction.
Date: August 5, 2001
Creator: Lyon, Richard
System: The UNT Digital Library
Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX (open access)

Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX

Dimensional changes related to temperature cycling of the beta and delta polymorphs of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are important for a variety of applications. The coefficient of thermal expansion (CTE) of the beta and delta phases are measured and reported in this work over a temperature range of -20 C to 215 C. In addition, dimensional changes associated with the phase transition were measured, both through the transition and back down. Initially, differential scanning calorimetry (DSC) was used to investigate back conversion of the delta phase to the beta phase polymorph. The most successful approach was first to measure the amount of the beta to delta conversion, then after a given cooling period a repeat analysis, to measure the heat consumed by a second pass through the beta to delta phase transition. In addition, TMA is used to measure the dimensional change of a 0.20-gram sample of HMX during its initial heating and then three days later during a 2nd heating. This HMX shows the beta to delta phase transition a second time, thereby confirming the back conversion from delta to beta phase HMX.
Date: August 5, 2004
Creator: Weese, R K; Burnham, A K & Maienschein, J L
System: The UNT Digital Library
''CPT Theorem'' for Accelerators (open access)

''CPT Theorem'' for Accelerators

In this paper we attempt to reveal common features in evolution of various colliders' luminosity over commissioning periods. A simplified formula, ''CPT theorem'' or CP = T, is proposed which relates the time needed for commissioning T, the ''complexity'' of the machine C and performance increase goal P.
Date: August 5, 2004
Creator: Shiltsev, Vladimir
System: The UNT Digital Library
The Deepest X-Ray View of High-Redshift Galaxies: Constraints on Low-Rate Black Hole Accretion (open access)

The Deepest X-Ray View of High-Redshift Galaxies: Constraints on Low-Rate Black Hole Accretion

This article exploits the 7 Ms Chandra observations in the Chandra Deep Field-South (CDF-S), the deepest X-ray survey to date, coupled with CANDELS/GOODS-S data, to measure the total X-ray emission arising from 2076 galaxies at 3.5 ≤ z ≤ 6.5.
Date: August 5, 2016
Creator: Vito, F.; Gilli, Roberto; Vignali, Christian; Brandt, William Nielsen; Comastri, Andrea; Yang, G. et al.
System: The UNT Digital Library
Development and test of the ITER SC conductor joints (open access)

Development and test of the ITER SC conductor joints

Joints for the ITER superconducting Central Solenoid should perform in rapidly varying magnetic field with low losses and low DC resistance. This paper describes the design of the ITER joint and presents its assembly process. Two joints were built and tested at the PTF facility at MIT. Test results are presented; losses in transverse and parallel field and the DC performance are discussed. The developed joint demonstrates sufficient margin for baseline ITRR operating scenarios.
Date: August 5, 1998
Creator: Gung, C. Y.; Jayakumar, R.; Manahan, R.; Martovetsky, N.; Michael, P.; Minervini, J. et al.
System: The UNT Digital Library
Development of A Microwave Assisted Particulate Filter Regeneration System (open access)

Development of A Microwave Assisted Particulate Filter Regeneration System

The need for active regeneration of diesel particulate filters and the advantages of microwave assisted regeneration are discussed. The current study has multiple objectives, which include developing a microwave assisted particulate filter regeneration system for future generation light-duty diesel applications, including PNGV type applications. A variable power 2.0 kW microwave system and a tuned waveguide were employed. Cavity geometry is being optimized with the aid of computational modeling and temperature measurements during microwave heating. A wall-flow ceramic-fiber filter with superior thermal shock resistance, high filtration efficiency, and high soot capacity was used. The microwave assisted particulate filter regeneration system has operated for more than 100 hours in an engine test-cell with a 5.9-liter diesel engine with automated split exhaust flow and by-pass flow capabilities. Filter regeneration was demonstrated using soot loads up to 10 g/liter and engine exhaust at idling flow rates as the oxygen source. A parametric study to determine the optimal combination of soot loading, oxidant flow rate, microwave power and heating time is underway. Preliminary experimental results are reported.
Date: August 5, 2001
Creator: Popuri, Sriram
System: The UNT Digital Library
Development of Neutral Red as a pH/pCO2 Luminescent Sensor for Biological Systems (open access)

Development of Neutral Red as a pH/pCO2 Luminescent Sensor for Biological Systems

This article demonstrates for the first time that Neutral Red (NR) can also serve as a CO2 sensor, because of NR’s unique optical properties, which change with dissolved carbon dioxide (dCO2) concentrations. In this article optical sensitivity of NR was quantified as a function of changes in absorption and emission spectra to dCO2 in a pH 7.3 buffer medium at eight dCO2 concentrations.
Date: August 5, 2021
Creator: Ericson, Megan N.; Shankar, Sindhu K.; Chahine, Laya M.; Omary, Mohammad A.; Hunt von Herbing, Ione & Marpu, Sreekar
System: The UNT Digital Library
Development of the third harmonic SC cavity at Fermilab (open access)

Development of the third harmonic SC cavity at Fermilab

The third harmonic 3.9 GHz superconducting cavity was recently proposed by DESY for a new generation of high brightness photo-injector (TTF photoinjector-2) to compensate nonlinear distortion of the longitudinal phase space due to RF curvature of the 1.3 GHz TESLA cavities [1,2]. Installation of the 3rd harmonic cavity will allow us to generate ultra-short (&lt;50 {micro}m rms) highly charged electron bunches with an extremely small transverse normalized emittance (&lt;1 {micro}m). This is required to support a new generation of linear colliders, free electron lasers and synchrotron radiation sources. In this paper we present the current status of the 3rd harmonic cavity being developed at Fermilab. We discuss the design procedure, the building and testing of the copper and niobium half-cells and components, the design of input and HOM couplers.
Date: August 5, 2004
Creator: al., Nikolay Solyak et
System: The UNT Digital Library