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Biosphere dose conversion Factor Importance and Sensitivity Analysis (open access)

Biosphere dose conversion Factor Importance and Sensitivity Analysis

This report presents importance and sensitivity analysis for the environmental radiation model for Yucca Mountain, Nevada (ERMYN). ERMYN is a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis concerns the output of the model, biosphere dose conversion factors (BDCFs) for the groundwater, and the volcanic ash exposure scenarios. It identifies important processes and parameters that influence the BDCF values and distributions, enhances understanding of the relative importance of the physical and environmental processes on the outcome of the biosphere model, includes a detailed pathway analysis for key radionuclides, and evaluates the appropriateness of selected parameter values that are not site-specific or have large uncertainty.
Date: October 15, 2004
Creator: Wasiolek, M.
Object Type: Report
System: The UNT Digital Library
ENHANCED PRACTICAL PHOTOSYNTHETIC CO{sub 2} MITIGATION (open access)

ENHANCED PRACTICAL PHOTOSYNTHETIC CO{sub 2} MITIGATION

This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 1/2/2004 through 4/1/2004. Specific results and accomplishments for the first quarter of 2004 include: (1) CRF-2 test system: After the recent successful test results were achieved, the system was taken off-line for re-sealing and other operational improvements to prepare for the next level of testing, which will include direct measurement of carbon uptake in addition to organism mass measurements. (2) 15 biomass slurry samples are currently being analyzed with carbon dating techniques at Galbraith Labs, and statistical analysis of the results will determine if pre and post test carbon analysis is an acceptable means for carbon uptake estimation. (3) Pilot Scale: Quantitative organism growth testing is underway in the pilot scale bioreactor. Problems with uniformity of organism loading delayed the start of quantitative testing, and it remains as a continuing issue that has not been completely resolved. (4) The sustainability test was begun with approximately 30 gallons of algae and 2 Omnisil membranes. The initial mass determination procedure was completed, and the biomass growth over the course of the experiment has been preliminarily quantified.
Date: April 15, 2004
Creator: Kremer, Gregory; Bayless, David J.; Vis, Morgan; Prudich, Michael; Cooksey, Keith & Muhs, Jeff
Object Type: Report
System: The UNT Digital Library
URI Program Final Report FY 2001 Grant for the University of Florida Training Reactor (open access)

URI Program Final Report FY 2001 Grant for the University of Florida Training Reactor

The purpose of the URI program is to upgrade and improve university nuclear research and training reactors and to contribute to strengthening the academic community's nuclear engineering infrastructure.
Date: March 15, 2004
Creator: Vernetson, William G.
Object Type: Report
System: The UNT Digital Library
The Effect of Government Actions on Environmental Technology Innovation: Applications to the Integrated Assessment of Carbon Sequestration Technologies (open access)

The Effect of Government Actions on Environmental Technology Innovation: Applications to the Integrated Assessment of Carbon Sequestration Technologies

This project seeks to improve the ability of integrated assessment models (IA) to incorporate changes in technology, especially environmental technologies, cost and performance over time. In this report, we present results of research that examines past experience in controlling other major power plant emissions that might serve as a reasonable guide to future rates of technological progress in carbon capture and sequestration (CCS) systems. In particular, we focus on U.S. and worldwide experience with sulfur dioxide (SO{sub 2}) and nitrogen oxide (NO{sub x}) control technologies over the past 30 years, and derive empirical learning rates for these technologies. The patterns of technology innovation are captured by our analysis of patent activities and trends of cost reduction over time. Overall, we found learning rates of 11% for the capital costs of flue gas desulfurization (FGD) system for SO{sub 2} control, and 13% for selective catalytic reduction (SCR) systems for NO{sub x} control. We explore the key factors responsible for the observed trends, especially the development of regulatory policies for SO{sub 2} and NO{sub x} control, and their implications for environmental control technology innovation.
Date: January 15, 2004
Creator: Rubin, E. S.; Hounshell, D. A.; Yeh, S.; Taylor, M.; Schrattenholzer, L.; Riahi, K. et al.
Object Type: Report
System: The UNT Digital Library
Materials System for Intermediate Temperature Solid Oxide Fuel Cell (open access)

Materials System for Intermediate Temperature Solid Oxide Fuel Cell

AC complex impedance spectroscopy studies were conducted on symmetrical cells of the type [gas, electrode/LSGM electrolyte/electrode, gas]. The electrode materials were slurry-coated on both sides of the LSGM electrolyte support. The electrodes selected for this investigation are candidate materials for SOFC electrodes. Cathode materials include La{sub 1-x}Sr{sub x}MnO{sub 3} (LSM), LSCF (La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3}), a two-phase particulate composite consisting of LSM + doped-lanthanum gallate (LSGM), and LSCF + LSGM. Pt metal electrodes were also used for the purpose of comparison. Anode material investigated was the Ni + GDC composite. The study revealed important details pertaining to the charge-transfer reactions that occur in such electrodes. The information obtained can be used to design electrodes for intermediate temperature SOFCs based on LSGM electrolyte.
Date: February 15, 2004
Creator: Pal, Uday B. & Gopalan, Srikanth
Object Type: Report
System: The UNT Digital Library
Transport, Targeting, and Applications of Metallic Functional Nanoparticles for Degradation of DNAPL Chlorinated Organic solvents (open access)

Transport, Targeting, and Applications of Metallic Functional Nanoparticles for Degradation of DNAPL Chlorinated Organic solvents

This project addresses the need for methods to remove or degrade subsurface contaminants that are present as dense non-aqueous phase liquids (DNAPLs), and act as long-term sources of groundwater contamination. The goal is to build on a particle-based approach to subsurface contaminant remediation that is based partly on the recent success in using nanoparticle iron to degrade chlorinated compounds dissolved in groundwater, and knowledge of how colloids migrate in porous media. The objective is to engineer reactive nanoparticles that can decompose and potentially isolate DNAPL pollutants in the subsurface.
Date: June 15, 2004
Creator: Lowry, Gregory; Majetich, Sara; Matyjaszewski, Krzysztof; Sholl, David & Tilton, Robert
Object Type: Report
System: The UNT Digital Library
Hydrogeologic Framework Model for the Saturated Zone Site Scale flow and Transport Model (open access)

Hydrogeologic Framework Model for the Saturated Zone Site Scale flow and Transport Model

The purpose of this report is to document the 19-unit, hydrogeologic framework model (19-layer version, output of this report) (HFM-19) with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results in accordance with AP-SIII.10Q, Models. The HFM-19 is developed as a conceptual model of the geometric extent of the hydrogeologic units at Yucca Mountain and is intended specifically for use in the development of the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]). Primary inputs to this model report include the GFM 3.1 (DTN: MO9901MWDGFM31.000 [DIRS 103769]), borehole lithologic logs, geologic maps, geologic cross sections, water level data, topographic information, and geophysical data as discussed in Section 4.1. Figure 1-1 shows the information flow among all of the saturated zone (SZ) reports and the relationship of this conceptual model in that flow. The HFM-19 is a three-dimensional (3-D) representation of the hydrogeologic units surrounding the location of the Yucca Mountain geologic repository for spent nuclear fuel and high-level radioactive waste. The HFM-19 represents the hydrogeologic setting for the Yucca Mountain area that covers about 1,350 km2 and includes a saturated thickness of about 2.75 km. The boundaries of the conceptual model were primarily …
Date: November 15, 2004
Creator: Miller, T.
Object Type: Report
System: The UNT Digital Library
eShadow: A tool for comparing closely related sequences (open access)

eShadow: A tool for comparing closely related sequences

Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human to primate or mouse to rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements. The eShadow tool is publicly available at http://eshadow.dcode.org/
Date: January 15, 2004
Creator: Ovcharenko, Ivan; Boffelli, Dario & Loots, Gabriela G.
Object Type: Article
System: The UNT Digital Library
Feature article: adoption of an official ISEA glossary (open access)

Feature article: adoption of an official ISEA glossary

The International Society for Exposure Analysis (ISEA) and its Nomenclature Committee have been involved since the mid-1990s in an intermittent but ongoing effort to develop an official ISEA glossary. Several related activities have stimulated greater interest and discussion nationally and internationally on a common exposure language. Among these activities are a 1997 Journal of Exposure Analysis and Environmental Epidemiology feature article on exposure and dose definitions and a 1999-initiated project of the International Programme on Chemical Safety (IPCS) (WHO/ILO/UNEP) to confront terminology issues hindering harmonization in the area of exposure assessment. Recently the ISEA members voted in support of adopting the IPCS glossary as the official ISEA glossary, and the ISEA Executive Board agreed to accept this recommendation. In this feature article we (1) describe the process through which the ISEA adopted the IPCS glossary as the official ISEA glossary, (2) present the joint IPC S/ISEA glossary of terms and their definitions, and (3) discuss plans for how the glossary can be used by ISEA and updated over time by ISEA and IPCS. The glossary is intended to be a living document that reflects the latest usage and maintains international harmonization of exposure terminology that can be practically applied to …
Date: September 15, 2004
Creator: Zartarian, Valerie; Bahadori, Tina & McKone, Thomas
Object Type: Article
System: The UNT Digital Library
SOLAR POWERING OF HIGH EFFICIENCY ABSORPTION CHILLER (open access)

SOLAR POWERING OF HIGH EFFICIENCY ABSORPTION CHILLER

This is the Final Report for two solar cooling projects under this Cooperative Agreement. The first solar cooling project is a roof-integrated solar cooling and heating system, called the Power Roof{trademark}, which began operation in Raleigh, North Carolina in late July 2002. This system provides 176 kW (50 ton) of solar-driven space cooling using a unique nonimaging concentrating solar collector. The measured performance of the system during its first months of operation is reported here, along with a description of the design and operation of this system. The second solar cooling system, with a 20-ton capacity, is being retrofit to a commercial office building in Charleston, South Carolina but has not yet been completed.
Date: November 15, 2004
Creator: Gee, Randy C.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION (open access)

DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION

Mineral carbonation is a promising concept for permanent CO{sub 2} sequestration due to the vast natural abundance of the raw minerals, the permanent storage of CO{sub 2} in solid form as carbonates, and the overall reaction being exothermic. However, the primary drawback to mineral carbonation is the reaction kinetics. To accelerate the reaction, aqueous carbonation processes are preferred, where the minerals are firstly dissolved in solution. In aqueous carbonation, the key step is the dissolution rate of the mineral, where the mineral dissolution reaction is likely to be surface controlled. In order to accelerate the dissolution process, the serpentine can be ground to very fine particle size (<37 {micro}m), but this is a very energy intensive process. Alternatively, magnesium could be chemically extracted in aqueous solution. Phase I showed that chemical surface activation helps to dissolve the magnesium from the serpentine minerals (particle size {approx}100 {micro}m), and furthermore, the carbonation reaction can be conducted under mild conditions (20 C and 650 psig) compared to previous studies that required >185 C, >1850 psig and <37 {micro}m particle size. Phase I also showed that over 70% of the magnesium can be extracted at ambient temperature leaving amorphous SiO{sub 2} with surface areas …
Date: November 15, 2004
Creator: Maroto-Valer, M. Mercedes; Andresen, John M. & Alexander, George
Object Type: Report
System: The UNT Digital Library
A 20-year data set of surface longwave fluxes in the Arctic (open access)

A 20-year data set of surface longwave fluxes in the Arctic

Creation of 20-year data set of surface infrared fluxes from satellite measurements. A reliable estimate of the surface downwelling longwave radiation flux (DLF) is a glaring void in available forcing data sets for models of Arctic sea ice and ocean circulation. We have developed a new method to estimate the DLF from a combination of satellite sounder retrievals and brightness temperatures from the TIROS Operational Vertical Sounder (TOVS), which has flown on NOAA polar-orbiting satellites continuously since late 1979. The overarching goal of this project was to generate a 20-year data set of surface downwelling longwave flux measurements from TOVS data over the Arctic Ocean. Daily gridded fields of DLF were produced with a spatial resolution of (100 km){sup 2} north of 60{sup o}N for 22.5 years rather than only 20. Surface measurements from the field station at Barrow, AK--part of the Atmospheric Radiation Measurement (ARM) Program --and from the Surface Heat Budget of the Arctic (SHEBA) were used to validate the satellite-derived fluxes and develop algorithm improvements for conditions that had resulted in systematic errors in early versions of the algorithm. The resulting data set has already been sent to two other investigators for incorporation into their research, and …
Date: June 15, 2004
Creator: Francis, Jennifer
Object Type: Report
System: The UNT Digital Library
Boundary Layer Cloudiness Parameterizations Using ARM Observations (open access)

Boundary Layer Cloudiness Parameterizations Using ARM Observations

This study used DOE ARM data and facilities to: (1) study macroscopic properties of continental stratus clouds at SGP and the factors controlling these properties, (2) develop a scientific basis for understanding the processes responsible for the formation of boundary layer clouds using ARM observations in conjunction with simple parametric models and LES, and (3) evaluate cumulus cloud characteristics retrieved from the MMCR operating at TWP-Nauru. In addition we have used high resolution 94 GHz observations of boundary layer clouds and precipitation to: (1) develop techniques for using high temporal resolution Doppler velocities to study large-eddy circulations and turbulence in boundary layer clouds and estimate the limitations of using current and past MMCR data for boundary layer cloud studies, (2) evaluate the capability and limitations of the current MMCR data for estimating reflectivity, vertical velocities, and spectral under low- signal-to-noise conditions associated with weak no n-precipitating clouds, (3) develop possible sampling modes for the new MMCR processors to allow for adequate sampling of boundary layer clouds, and (4) retrieve updraft and downdraft structures under precipitating conditions.
Date: September 15, 2004
Creator: Albrecht, Bruce
Object Type: Report
System: The UNT Digital Library
Efficient algorithms for multi-file caching (open access)

Efficient algorithms for multi-file caching

Multi-File Caching issues arise in applications where a set of jobs are processed and each job requests one or more input files. A given job can only be started if all its input files are preloaded into a disk cache. Examples of applications where Multi-File caching may be required are scientific data mining, bit-sliced indexes, and analysis of sets of vertically partitioned files. The difference between this type of caching and traditional file caching systems is that in this environment, caching and replacement decisions are made based on ''combinations of files (file bundles),'' rather than single files. In this work we propose new algorithms for Multi-File caching and analyze their performance. Extensive simulations are presented to establish the effectiveness of the Multi-File caching algorithm in terms of job response time and job queue length.
Date: March 15, 2004
Creator: Otoo, Ekow J.; Rotem, Doron & Seshadri, Sridhar
Object Type: Article
System: The UNT Digital Library
Understanding the Relationship Between Filling Pattern and Part Quality in Die Casting (open access)

Understanding the Relationship Between Filling Pattern and Part Quality in Die Casting

The overall objective of this research project was to investigate phenomena involved in the filling of die cavities with molten alloy in the cold chamber die-casting process. It has long been recognized that the filling pattern of molten metal entering a die cavity influences the quality of die-cast parts. Filling pattern may be described as the progression of molten metal filling the die cavity geometry as a function of time. The location, size and geometric configuration of points of metal entry (gates), as well as the geometry of the casting cavity itself, have great influence on filling patterns. Knowledge of the anticipated filling patterns in die-castings is important for designers. Locating gates to avoid undesirable flow patterns that may entrap air in the casting is critical to casting quality - as locating vents to allow air to escape from the cavity (last places to fill). Casting quality attributes that are commonly flow related are non-fills, poor surface finish, internal porosity due to trapped air, cold shuts, cold laps, flow lines, casting skin delamination (flaking), and blistering during thermal treatment.
Date: March 15, 2004
Creator: Brevick, Jerald & Miller, R. Allen
Object Type: Report
System: The UNT Digital Library
Isotropic-liquid crystalline phase diagram of a CdSe nanorod solution (open access)

Isotropic-liquid crystalline phase diagram of a CdSe nanorod solution

None
Date: January 15, 2004
Creator: Li, Liang-Shi; Marjanska, Malgorzata; Park, Gregory H. J.; Pines, Alexander & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors (Workshop Report) (open access)

Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors (Workshop Report)

The ''Workshop on Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors'' was convened to determine the degree to which an increased effort in modeling and simulation could help bridge the gap between the data that is needed to support the implementation of these advanced nuclear technologies and the data that can be obtained in available experimental facilities. The need to develop materials capable of performing in the severe operating environments expected in fusion and fission (Generation IV) reactors represents a significant challenge in materials science. There is a range of potential Gen-IV fission reactor design concepts and each concept has its own unique demands. Improved economic performance is a major goal of the Gen-IV designs. As a result, most designs call for significantly higher operating temperatures than the current generation of LWRs to obtain higher thermal efficiency. In many cases, the desired operating temperatures rule out the use of the structural alloys employed today. The very high operating temperature (up to 1000 C) associated with the NGNP is a prime example of an attractive new system that will require the development of new structural materials. Fusion power plants represent an even greater challenge to structural materials …
Date: July 15, 2004
Creator: Stoller, RE
Object Type: Report
System: The UNT Digital Library
NEW SYSTEMS FOR WASTE PROCESSING OF TRITIUM-CONTAINING GASESAT THE SAVANNAH RIVER SITE (open access)

NEW SYSTEMS FOR WASTE PROCESSING OF TRITIUM-CONTAINING GASESAT THE SAVANNAH RIVER SITE

A project to relocate and consolidate tritium processing activities from old, second generation buildings to newer buildings was initiated in the late 1990's at the Savannah River Site (SRS). This project replaces two existing gaseous process waste treatment systems currently operating in an older facility. The new waste gas processing systems located in the newer facility use recent technology, including metal getters, an innovative permeator design, and TCAP--Thermal Cycling Absorption Process--technology for removal of residual tritium prior to releasing the effluent to the environment. Startup testing results and corresponding lessons learned for these systems are presented. These systems have successfully completed startup testing and are operational.
Date: August 15, 2004
Creator: WILLIAM, JACOBS
Object Type: Article
System: The UNT Digital Library
MAG-GATE System for Molten metal Flow Control (open access)

MAG-GATE System for Molten metal Flow Control

The need for improved active flow control has been recognized as part of the Steel Industry Technology Roadmap. Under TRP 9808 for the American Iron and Steel Institute and the Department of Energy, Concept Engineering Group Inc. has developed MAG-GATE{trademark}, an electromagnetic system for active molten metal flow control. Two hot steel tests were successfully conducted in 2003 at the Whemco Foundry Division, Midland, PA. Approximately 110,000 pounds of 0.2% carbon steel were poured through the device subject to electromagnetic flow control. Excellent agreement between predicted and actual flow control was found. A survey of the molten metal flow control practices at 100 continuous casters in North America was also conducted in 2003. This report summarizes the results of the development program to date. Preliminary designs are described for the next step of a beta test at an operating billet/bloom or slab caster.
Date: May 15, 2004
Creator: Nathenson, Richard D.
Object Type: Report
System: The UNT Digital Library
Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report (open access)

Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report

In this quarter, the field, theoretical and programming works have been performed toward achieving the research goals set in the proposal. The main accomplishments in this quarter included: (1) two more sets of field tests have been conducted in an underground coal mine, (2) optimization studies of the control parameters have been conducted, (3) method to use torque to thrust ratio as indicator of rock relative hardness has also been explored, and (3) about 97% of the development work for the roof geology mapping program, MRGIS, has completed, (4) A special version of the geology mapping program for a limestone mine has been developed. The field test for the software and hardware has been successfully finished.
Date: September 15, 2004
Creator: Peng, Syd S.
Object Type: Report
System: The UNT Digital Library
Miniature Chemical Sensor combining Molecular Recognition with Evanescent Wave Cavity Ring-Down Spectroscopy (open access)

Miniature Chemical Sensor combining Molecular Recognition with Evanescent Wave Cavity Ring-Down Spectroscopy

To address the chemical sensing needs of DOE, a new class of chemical sensors is being developed that enables qualitative and quantitative, remote, real-time, optical diagnostics of chemical species in hazardous gas, liquid, and semi-solid phases by employing evanescent wave cavity ring-down spectroscopy (EW-CRDS). The feasibility and sensitivity of EW-CRDS was demonstrated previously under Project No.60231. The objective of this project is to enhance the selectivity and range of application of EW-CRDS. Selectivity is achieved spectroscopically by using vibrational overtones in the near infrared and chemically by using modified surfaces to encourage selective adsorption of analyte while preventing non-selective adsorption. The range of application is expanded by extending EW-CRDS to liquids and by combining EW-CRDS with the unique optical properties of nanoparticles.
Date: June 15, 2004
Creator: Pipino, Andrew C. R. & Meuse, Curtis W.
Object Type: Report
System: The UNT Digital Library
Mechanism of lipid lowering in mice expressing human apolipoprotein A5 (open access)

Mechanism of lipid lowering in mice expressing human apolipoprotein A5

Recently, we reported that apoAV plays key role in triglycerides lowering. Here, we attempted to determine the mechanism underlying this hypotriglyceridemic effect. We showed that triglyceride turnover is faster in hAPOA5 transgenic compared to wild type mice. Moreover, both apoB and apoCIII are decreased and LPL activity is increased in postheparin plasma of hAPOA5 transgenic mice. These data suggest a decrease in size and number of VLDL. To further investigate the mechanism of hAPOA5 in hyperlipidemic background, we intercrossed hAPOA5 and hAPOC3 transgenic mice. The effect resulted in a marked decreased of VLDL triglyceride, cholesterol, apolipoproteins B and CIII. In postprandial state, the triglyceride response is abolished in hAPOA5 transgenic mice. We demonstrated that in response to the fat load in hAPOA5XhAPOC3 mice, apoAV shifted from HDL to VLDL, probably to limit the elevation of triglycerides. In vitro, apoAV activates lipoprotein lipase. However, apoAV does not interact with LPL but interacts physically with apoCIII. This interaction does not seem to displace apoCIII from VLDL but may induce conformational change in apoCIII and consequently change in its function leading the activation of lipoprotein lipase.
Date: January 15, 2004
Creator: Fruchart-Najib, Jamila; Bauge, Eric; Niculescu, Loredan-Stefan; Pham, Tatiana; Thomas, Benoit; Rommens, Corinne et al.
Object Type: Article
System: The UNT Digital Library
Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub t} in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub t} in Au+Au collisions at {radical}s{sub NN} = 130 GeV

We present STAR measurements of charged hadron production as a function of centrality in Au + Au collisions at {radical}s{sub NN} = 130 GeV. The measurements cover a phase space region of 0.2 < p{sub T} < 6.0 GeV/c in transverse momentum and 11 < {eta} < 1 in pseudorapidity. Inclusive transverse momentum distributions of charged hadrons in the pseudorapidity region 0.5 < |{eta}| < 1 are reported and compared to our previously published results for |{eta}| < 0.5. No significant difference is seen for inclusive p{sub T} distributions of charged hadrons in these two pseudorapidity bins. We measured dN/d{eta} distributions and truncated mean p{sub T} in a region of p{sub T} > P{sub T}{sup cut}, and studied the results in the framework of participant and binary scaling. No clear evidence is observed for participant scaling of charged hadron yield in the measured pT region. The relative importance of hard scattering process is investigated through binary scaling fraction of particle production.
Date: April 15, 2004
Creator: Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D. et al.
Object Type: Article
System: The UNT Digital Library
Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids (open access)

Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids

Nuclear magnetic resonance (NMR) techniques were used to study crown ether-water interactions in solvents of low dielectric constants such as chloroform and carbon tetrachloride. Water forms a 1:1 complex with a number of crown ethers including 12-crown-4, 15-crown-5, 18-crown-6, dicyclohexano-18=crown-6, dicyclohexano-24-crown 8, and dibenzl-24-crown-8 in chloroform. Among these crown ethers, the 18-crown-6-H2 complex has the largest equilibrium constant (K=545) and 97% of the crown is complexed to water in chloroform. Addition of carbon tetrachloride to chloroform lowers the equilibrium constants of the crown-water complexes. The partition coefficients of crown ethers (D=crown in water/crown in solvent) between water and organic solvent also vary with solvent composition.
Date: March 15, 2004
Creator: Wai, Chien M.; Rustenholtz, Anne; Wang, Shaofen; Lee, Su-Chen; Herman, Jamie & Porter, Richard A.
Object Type: Report
System: The UNT Digital Library