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Particle Correlations with the PHENIX Experiment (open access)

Particle Correlations with the PHENIX Experiment

Results of identical pion correlations from the first year of data collection with the PHENIX detector at RHIC ({radical}S{sub NN} = 130 GeV) are presented. PHENIX has good particle identification using an electromagnetic calorimeter for timing, leading to identified pions from .2 to 1 GeV/c. This extends the range of previously measured correlation radii at this energy to (k{sub T}) = 633MeV/c. The beam energy dependence of the HBT radii are studied in depth and no significant dependence of the transverse radii is present. The longitudinal correlation length has a moderate energy dependence. Furthermore, theoretical predictions of R{sub out}/R{sub side} severely underpredict the measured ratio, which is consistent with unity for all k{sub T}. The implications of these results are considered.
Date: January 20, 2002
Creator: Johnson, S C
System: The UNT Digital Library
Structure of the LDL receptor extracellular domain at endosomalpH (open access)

Structure of the LDL receptor extracellular domain at endosomalpH

The structure of the low-density lipoprotein receptor extracellular portion has been determined. The document proposes a mechanism for the release of lipoprotein in the endosome. Without this release, the mechanism of receptor recycling cannot function.
Date: December 20, 2002
Creator: Rudenko, Gabby; Henry, Lisa; Henderson, Keith; Ichtchenko, Konstantin; Brown, Michael S.; Goldstein, Joseph L. et al.
System: The UNT Digital Library
Experimental evidence of a dynamic Jahn-Teller effect in C-60(+) (open access)

Experimental evidence of a dynamic Jahn-Teller effect in C-60(+)

Detailed analysis of the HOMO bandshape in the photoelectron spectrum of gaseous C60 reveals a dynamic Jahn-Teller effect in the ground state of C60+. The direct observation of three tunneling states asserts a D3d geometry for the isolated cation, originating from a strong vibronic coupling. These results show that the ionic motion of the ions plays an important role in the electron-phonon interaction.
Date: May 20, 2002
Creator: Canton, S.E.; Yencha, A.J.; Kukk, E.; Bozek, J.D.; Lopes, M.C.A.; Snell, G. et al.
System: The UNT Digital Library
The Science of Climate Change (open access)

The Science of Climate Change

What constitutes 'dangerous anthropogenic interference' is a value judgment arrived at through a socio-political process, taking issues like equity and sustainability into account. Science provides key information needed to arrive at an informed judgment. However, that judgment is primarily a political one, and not a purely scientific decision. Such judgments are based on risk assessment, and lead to risk management choices by decision makers, about actions and policies.
Date: September 20, 2002
Creator: Makundi, Willy R.
System: The UNT Digital Library
High-Frequency and Very-high-Frequency (HF&VHF) above-groundelectromagnetic impedance measurements (open access)

High-Frequency and Very-high-Frequency (HF&VHF) above-groundelectromagnetic impedance measurements

We have field-tested an apparatus for measuring the electromagnetic impedance above the ground at a plurality of frequencies in the 0.3 - 30 MHz range. This window in the frequency spectrum, which lies between frequencies used for GPR and those used for conventional loop-loop EM soundings, has not been used because of difficulties in fielding equipment for making absolute and accurate measurements. Model and physical parameter studies however confirm that data in this frequency band can be used to construct high-resolution maps of electrical conductivity and permittivity of near-surface material. Our equipment was assembled using commercial electric and magnetic antennas. The magnetic loop source is excited by a conventional signal generator - power amplifier assembly. Signal detection is accomplished using RF lock-in amplifiers. All system elements are appropriately isolated by optic - fiber links. We estimate a measurement accuracy of about {+-} 10% for an 8-m separation between source and detector. Field tests were done at the University of California Richmond Field Station where the near surface electrical structure is well known. The experimental data at this site are mainly a function of electrical conductivity. In this context, we have obtained good agreement with the known local variations in resistivity …
Date: September 20, 2002
Creator: Frangos, William; Becker, Alex & Lee, K. H.
System: The UNT Digital Library
The organizing principle: microenvironmental influences in the normal and malignant breast (open access)

The organizing principle: microenvironmental influences in the normal and malignant breast

The current paradigm for cancer initiation and progression rests on the groundbreaking discoveries of oncogenes and tumor suppressor genes. This framework has revealed much about the role of genetic alterations in the underlying signaling pathways central to normal cellular function and to tumor progression. However, it is clear that single gene theories or even sequential acquisition of mutations underestimate the nature of the genetic and epigenetic changes in tumors, and do not account for the observation that many cancer susceptibility genes (e.g. BRCA1, APC) show a high degree of tissue specificity in their association with neoplastic transformation. Therefore, the cellular and tissue context itself must confer additional and crucial information necessary for mutated genes to exert their influence. A considerable body of evidence now shows that cell - cell and cell - extracellular matrix (ECM) interactions are essential organizing principles that help define the nature of the tissue context, and play a crucial role in regulating homeostasis and tissue specificity. How this context determines functional integrity, and how its loss can lead to malignancy, appears to have much to do with tissue structure and polarity.
Date: August 20, 2002
Creator: Bissell, Mina; Radisky, Derek C.; Rizki, Aylin; Weaver, Valerie M. & Petersen, Ole W.
System: The UNT Digital Library
Energy-efficient appliance labeling in China: Lessons for successful labeling programs in varied markets (open access)

Energy-efficient appliance labeling in China: Lessons for successful labeling programs in varied markets

Appliance ownership and production has increased dramatically in China in the past two decades. From extremely low levels in 1980, China's appliance industry has become one of the largest in the world, with sales topping U.S. $14.4 billion in 2000. In 1981, less than 1 percent of urban Chinese households owned a refrigerator; by 1998, that number had increased to over 75 percent. This dramatic increase in sales and ownership leads to an excellent opportunity to impact energy consumption in China by affecting the energy efficiency of appliances being bought and sold. In general, Chinese consumers value energy efficiency and are knowledgeable about the operating costs of major appliances. However, the Chinese marketplace does not provide information that consumers trust about the energy consumption of specific products. Thus, several interdependent organizations have emerged in China to provide information and market supports for energy efficiency. This paper describes the appliance market in China and the evolution of its standards and labeling programs and the agencies that implement them. It discusses the authors' work with these organizations in developing energy efficiency criteria and supporting an energy efficiency endorsement labeling program in China. It describes how the authors have used their experience with …
Date: August 20, 2002
Creator: Lin, Jiang; Townend, Jeanne; Fridley, David; McNeil, Gary; Silva, Tony & Clark, Robin
System: The UNT Digital Library
Heavy ion physics at RHIC and in CMS and the participation of the US nuclear physicists in CMS (open access)

Heavy ion physics at RHIC and in CMS and the participation of the US nuclear physicists in CMS

The field of relativistic heavy ion physics entered a new era with the start of the physics program at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory on Long Island, New York. This dedicated facility allows extensive studies of the nuclear matter phase diagram at the highest temperatures so far available in the laboratory. The goal of the program is to conclusively establish the existence of the deconfined state of nuclear matter predicted by QCD, the Quark Gluon Plasma (QGP), and study its properties.
Date: May 20, 2002
Creator: Vogt, Ramona; Wyslouch, Bolek & Yepes, Pablo
System: The UNT Digital Library
In situ Gas Conditioning in Fuel Reforming for Hydrogen Generation (open access)

In situ Gas Conditioning in Fuel Reforming for Hydrogen Generation

The production of hydrogen for fuel cell applications requires cost and energy efficient technologies. The Absorption Enhanced Reforming (AER), developed at ZSW with industrial partners, is aimed to simplify the process by using a high temperature in situ CO2 absorption. The in situ CO2 removal results in shifting the steam reforming reaction equilibrium towards increased hydrogen concentration (up to 95 vol%). The key part of the process is the high temperature CO2 absorbent. In this contribution results of Thermal Gravimetric Analysis (TGA) investigations on natural minerals, dolomites, silicates and synthetic absorbent materials in regard of their CO2 absorption capacity and absorption/desorption cyclic stability are presented and discussed. It has been found that the inert parts of the absorbent materials have a structure stabilizing effect, leading to an improved cyclic stability of the materials.
Date: September 20, 2002
Creator: Bandi, A.; Specht, M.; Sichler, P. & Nicoloso, N.
System: The UNT Digital Library
Integration and conventional systems at STAR (open access)

Integration and conventional systems at STAR

At the beginning of the design and construction of the STAR Detector, the collaboration assigned a team of physicists and engineers the responsibility of coordinating the construction of the detector. This group managed the general space assignments for each sub-system and coordinated the assembly and planning for the detector. Furthermore, as this group was the only STAR group with the responsibility of looking at the system as a whole, the collaboration assigned it several tasks that spanned the different sub-detectors. These items included grounding, rack layout, cable distribution, electrical, power and water, and safety systems. This paper describes these systems and their performance.
Date: February 20, 2002
Creator: Matis, Howard S.; Brown, Ralph L.; Christie, William; Edwards, W.R.; Jared, Richard; Minor, Bob et al.
System: The UNT Digital Library
Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents (open access)

Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents

The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash …
Date: September 20, 2002
Creator: Hemmer, G.; Kasper, G.; Wang, J. & Schaub, G.
System: The UNT Digital Library
Studies of Alkali Sorption Kinetics for Pressurized Fluidized Bed Combustion by High Pressure Mass Spectrometry (open access)

Studies of Alkali Sorption Kinetics for Pressurized Fluidized Bed Combustion by High Pressure Mass Spectrometry

This work describes the first approach to use High Pressure Mass Spectrometry (HPMS) for the quantification and analysis of alkali species in a gas stream downstream a sorbent bed of different tested alumosilicates.
Date: September 20, 2002
Creator: Wolf, K.J.; Willenborg, W.; Fricke, C.; Prikhodovsky, A.; Hilpert, K. & Singheiser, L.
System: The UNT Digital Library
Techniques for Mercury Control and Measurement in Gasification Systems (open access)

Techniques for Mercury Control and Measurement in Gasification Systems

A major concern for power systems that use coal as an energy source is the air emissions from the plant. Although certain air emissions are currently regulated, the emergence of new regulations for other pollutants are on the horizon. Gasification is an important strategy for increasing the utilization of abundant domestic coal reserves. The Department of Energy envisions increased use of gasification in the United States during the next twenty years. As such, the DOE Gasification Technologies Program will strive to approach a near-zero emissions goal with respect to pollutants. The mercury research detailed in this proposal addresses the Gas Cleaning and Conditioning program technology area.
Date: September 20, 2002
Creator: Granite, E. J.; King, W. P. & Pennline, H. W.
System: The UNT Digital Library
A Hybrid Gas Cleaning Process for Production of Ultraclean Syngas (open access)

A Hybrid Gas Cleaning Process for Production of Ultraclean Syngas

The overall objective of this project is to develop technologies for cleaning/conditioning IGCC generated syngas to meet contaminant tolerance limits for fuel cell and chemical production applications. The specific goals are to develop processes for (1) removal of reduced sulfur species to sub-ppm levels using a hybrid process consisting of a polymer membrane and a regenerable ZnO-coated monolith or a mixed metal oxide sorbent; (2) removal of hydrogen chloride vapors to sub-ppm levels using an inexpensive, high-surface-area material; and (3) removal of NH3 with acidic adsorbents followed by conversion of this NH3 into nitrogen and water. Existing gasification technologies can effectively and efficiently convert a wide variety of carbonaceous feedstocks (coal, petcoke, resids, biomass, etc.) into syngas, which predominantly contains carbon monoxide and hydrogen. Unfortunately, the impurities present in these carbonaceous feedstocks are converted to gaseous contaminants such as H2S, COS, HCl, NH3, alkali macromolecules and heavy metal compounds (such as Hg) during the gasification process. Removal of these contaminants using conventional processes is thermally inefficient and capital intensive. This research and development effort is focused on investigation of modular processes for removal of sulfur, chlorine, nitrogen and mercury compounds from syngas at elevated temperature and pressures at significantly lower …
Date: September 20, 2002
Creator: Merkel, Timothy C.; Turk, Brian S.; Gupta, Raghubir P.; Cicero, Daniel C. & Jain, Suresh C.
System: The UNT Digital Library
Earth Systems Questions in Experimental Climate Change Science: Pressing Questions and Necessary Facilities (open access)

Earth Systems Questions in Experimental Climate Change Science: Pressing Questions and Necessary Facilities

Sixty-four scientists from universities, national laboratories, and other research institutions worldwide met to evaluate the feasibility and potential of the Biosphere2 Laboratory (B2L) as an inclusive multi-user scientific facility (i.e., a facility open to researchers from all institutions, according to agreed principles of access) for earth system studies and engineering research, education, and training relevant to the mission of the United States Department of Energy (DOE).
Date: May 20, 2002
Creator: Osmond, B.
System: The UNT Digital Library
Thermodynamic Properties Of Alkali Species In Coal Based Combined Cycle Power Systems (open access)

Thermodynamic Properties Of Alkali Species In Coal Based Combined Cycle Power Systems

The aim of this project is to support the development of a concept for a successful alkali removal. Two strategies are possible: optimizing the alkali retention potential of the coal ash slag in the combustion chamber and the liquid slag separators and separate alkali removal with solid sorbents (getters) at temperatures below 1450 C. Therefore in a first step the alkali partial pressure over coal ash slag should be determined in order to get information about the retention potential of the slag. The influence of additives on the retention potential of the slag should be investigated. The measurements should show if the alkali partial pressure over the slag is generally low enough in case of thermodynamic equilibrium. In case of too high alkali partial pressures a separate alkali removal is needed. Therefore in a second step commercial sorbent materials should be investigated concerning their sorption potential for alkalis. To get information about the influence of getter components on the sorption potential some mixtures of pure components, predicted by thermodynamic modeling to be most effective, should be investigated.
Date: September 20, 2002
Creator: Willenborg, W.; Wolf, K.J.; Fricke, C.; Moeller, M.; Prikhodovsky, A.; Hilpert, K. et al.
System: The UNT Digital Library
Development of the Ultra-Clean Dry Cleanup Process for Coal-Based Syngases (open access)

Development of the Ultra-Clean Dry Cleanup Process for Coal-Based Syngases

The Siemens Westinghouse Power Corporation (SWPC) has proposed a novel scheme for polishing sulfur species, halides, and particulate from syngas to meet stringent cleaning requirements, the ''Ultra-Clean syngas polishing process.'' The overall development objective for this syngas polishing process is to economically achieve the most stringent cleanup requirements for sulfur species, halide species and particulate expected for chemical and fuel synthesis applications (total sulfur species < 60 ppbv, halides < 10 ppbv, and particulate < 0.1 ppmw). A Base Program was conducted to produce ground-work, laboratory test data and process evaluations for a conceptual feasibility assessment of this novel syngas cleaning process. Laboratory testing focused on the identification of suitable sulfur and halide sorbents and operating temperatures for the process. This small-scale laboratory testing was also performed to provide evidence of the capability of the process to reach its stringent syngas cleaning goals. Process evaluations were performed in the Base Program to identify process alternatives, to devise process flow schemes, and to estimate process material & energy balances, process performance, and process costs. While the work has focused on sulfur, halide, and particulate control, considerations of ammonia, and mercury control have also been included.
Date: September 20, 2002
Creator: Newby, R. A.; Slimane, R. B.; Lau, F. S. & Jain, S. C.
System: The UNT Digital Library
High Temperature Flue Gas Desulfurization In Moving Beds With Regenerable Copper Based Sorbents (open access)

High Temperature Flue Gas Desulfurization In Moving Beds With Regenerable Copper Based Sorbents

The objective of this study was to develop new and improved regenerable copper based sorbent for high temperature flue gas desulfurization in a moving bed application. The targeted areas of sorbent improvement included higher effective capacity, strength and long-term durability for improved process control and economic utilization of the sorbent.
Date: September 20, 2002
Creator: Cengiz, P. A.; Ho, K. K.; Abbasian, J. & Lau, F. S.
System: The UNT Digital Library
Electrochemical Membrane Separation (EMS) of Hydrogen Sulfide from Coal Gasification Streams (open access)

Electrochemical Membrane Separation (EMS) of Hydrogen Sulfide from Coal Gasification Streams

The goal of this work is to prepare an electrolytic cell for scale-up that is capable of removing H2S continuously. The major hurdles that remain are cathode selection and optimizing cell design and operating conditions. Studies have focused upon determining critical cell parameters for process scale-up as well as finding more stable and catalytically active cathode materials.
Date: September 20, 2002
Creator: Burke, A.A.; Winnick, J.; Liu, M. & Li, S.
System: The UNT Digital Library
Source-independent full waveform inversion of seismic data (open access)

Source-independent full waveform inversion of seismic data

A rigorous full waveform inversion of seismic data has been a challenging subject partly because of the lack of precise knowledge of the source. Since currently available approaches involve some form of approximations to the source, inversion results are subject to the quality and the choice of the source information used. We propose a new full waveform inversion methodology that does not involve source spectrum information. Thus potential inversion errors due to source estimation can be eliminated. A gather of seismic traces is first Fourier-transformed into the frequency domain and a normalized wavefield is obtained for each trace in the frequency domain. Normalization is done with respect to the frequency response of a reference trace selected from the gather, so the complex-valued normalized wavefield is dimensionless. The source spectrum is eliminated during the normalization procedure. With its source spectrum eliminated, the normalized wavefield allows us construction of an inversion algorithm without the source information. The inversion algorithm minimizes misfits between measured normalized wavefield and numerically computed normalized wavefield. The proposed approach has been successfully demonstrated using a simple two-dimensional scalar problem.
Date: March 20, 2002
Creator: Lee, Ki Ha & Kim, Hee Joon
System: The UNT Digital Library
Development of a Liquid Metal Based Fuel Gas Scrubbing System (open access)

Development of a Liquid Metal Based Fuel Gas Scrubbing System

The objective of this research project is to perform studies on an analogous room temperature packed bed scrubber operating under non-wetting conditions, providing insight and understanding towards the development of a high temperature packed bed gas scrubber irrigated by molten tin.
Date: September 20, 2002
Creator: Chang, Boon Fuei; Swithenbank, Jim; Sharifi, Vida Nasserzadeh & Warner, Noel
System: The UNT Digital Library
RELATIVISTIC HEAVY ION PHYSICS : RESULTS FROM AGS TO RHIC. (open access)

RELATIVISTIC HEAVY ION PHYSICS : RESULTS FROM AGS TO RHIC.

High-energy collisions of heavy ions provide a means to study QCD in a regime of high parton density, and may provide insight into its phme structure. Results from the four experiments at RHIC (BRAHMS, PHENIX, PHOBOS and STAR) are presented, and placed in context with the lower energy data from the AGS and SPS accelerators. The focus is on the insights these measurements provide into the time history of the collision process. Taken together, the data point to the creation of a deconfined state of matter that forms quickly, expands rapidly and freezes out suddenly. With the new RHIC data, systematic data now exists for heavy ion collisions as a function of {radical}s over several orders of magnitude and as a function of impact parameter. These data test the interplay between hard and soft processes in a large-volume system where nucleons are struck multiple times. The data is consistent with creating a deconfined state (jet quenching) that forms quickly (saturation models), expands rapidly (radial and elliptic flow) and freezes out suddenly (single freezeout and blast wave fits). There are also intriguing connections with particle production in elementary systems, which point to the role of the energy available for particle production …
Date: June 20, 2002
Creator: Steinberg, Peter
System: The UNT Digital Library
Report of the Snowmass M6 Working Group on high intensity proton sources (open access)

Report of the Snowmass M6 Working Group on high intensity proton sources

The U.S. high-energy physics program needs an intense proton source, a 1-4 MW Proton Driver (PD), by the end of this decade. This machine will serve as a stand-alone facility that will provide neutrino superbeams and other high intensity secondary beams such as kaons, muons, neutrons, and anti-protons (cf. E1 and E5 group reports) and also serve as the first stage of a neutrino factory (cf. M1 group report). It can also be a high brightness source for a VLHC. Based on present accelerator technology and project construction experience, it is both feasible and cost-effective to construct a 1-4 MW Proton Driver. Two recent PD design studies have been made, one at FNAL and the other at the BNL. Both designed PD's for 1 MW proton beams at a cost of about U.S. $200M (excluding contingency and overhead) and both designs were upgradeable to 4 MW. An international collaboration between FNAL, BNL and KEK on high intensity proton facilities is addressing a number of key design issues. The superconducting (sc) RF cavities, cryogenics, and RF controls developed for the SNS can be directly adopted to save R&D efforts, cost, and schedule. PD studies are also actively being pursued at Europe …
Date: August 20, 2002
Creator: Wei, Weiren Chou and J.
System: The UNT Digital Library
Design features of high-intensity medium-energy superconducting heavy-ion Linac. (open access)

Design features of high-intensity medium-energy superconducting heavy-ion Linac.

The proposed Rare Isotope Accelerator (RIA) requires the construction of a cw 1.4 GV superconducting (SC) linac that is capable of producing 400 kW beams of all ions from protons at 900 MeV to uranium at 400 MeV/u. The design of such a linac was outlined at the previous Linac conference. This linac will accelerate multiple-charge-states (multi-q) of the heaviest ion beams, for which the beam current is limited by ion-source performance. The linac consists of two different types of accelerating and focusing lattice: for uranium below {approx}85 MeV/u the focusing is provided by SC solenoids installed in cryostats with the SC resonators while in the high-beta section the focusing elements are located outside of the cryostats. A detailed design has been developed for the focusing-accelerating lattice of the linac. Beam dynamics studies have been performed with the goal of optimization of the linac structure in order to reduce a possible effective emittance growth of the multi-q uranium beam. A wide tuning range of the accelerating and focusing fields is required for acceleration of the variety of ions with different charge-to-mass ratios to the highest possible energy in single charge state mode. The focusing must be retuned for different ion …
Date: September 20, 2002
Creator: Ostroumov, P. N.
System: The UNT Digital Library