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Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV
Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.
Date:
October 6, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Multi-strange baryon production in Au+Au collisions at {radical}s{sub NN} = 130 GeV
The transverse mass spectra and mid-rapidity yields for {Xi}s and {Omega}s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to {pi}, K, p and {lambda}s.
Date:
July 30, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Multi-strange baryon production in Au-Au collisions at sqrt(sNN) = 130 GeV
The transverse mass spectra and mid-rapidity yields for {Xi}s and {Omega}s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to {pi}, K, p and {Lambda}s.
Date:
July 31, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Particle-type dependence of azimuthal anisotropy and nuclearmodification of particle production in Au+Au collisions at sNN = 200GeV
We present STAR measurements of the azimuthal anisotropy parameter v{sub 2} and the binary-collision scaled centrality ratio R{sub CP} for kaons and lambdas ({Lambda} + {bar {Lambda}}) at mid-rapidity in Au+Au collisions at {radical}s{sub NN} = 200 GeV. In combination, the v{sub 2} and R{sub CP} particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish p{sub T} {approx} 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K{sub S}{sup 0} and {Lambda} + {bar {Lambda}} v{sub 2} values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.
Date:
June 18, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Pion-Kaon correlations in central Au+Au collisions at {radical}(s{sub NN}) = 130 GeV
No abstract prepared.
Date:
July 31, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV
Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse momentum range 1.2 < p{sub T} < 3.0 GeV/c is measured to be 1.19 {+-} 0.05(stat) {+-} 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + {bar p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.
Date:
September 16, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Rapidity and centrality dependence of proton and anti-proton production from 197Au+197Au collisions at {radical}(s{sub NN}) = 130 GeV
We report on the rapidity and centrality dependence of proton and anti-proton transverse mass distributions from {sup 197}Au + {sup 197}Au collisions at {radical}s{sub NN} = 130 GeV as measured by the STAR experiment at RHIC. Our results are from the rapidity and transverse momentum range of |y| < 0.5 and 0.35 < p{sub t} < 1.00 GeV/c. For both protons and anti-protons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y| < 0.5. Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton(anti-proton) yields and transverse mass distributions the possibility of pre-hadronic collective expansion may have to be taken into account.
Date:
June 20, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Transverse-Momentum and Collision Energy Dependence of High p{sub T} Hadron Suppression in Au+Au Collisions at Ultrarelativistic Energies
No abstract prepared.
Date:
September 2, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Three-pion Hanbury-Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment
Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at {radical}s{sub NN} = 130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freezeout. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.
Date:
June 19, 2003
Creator:
Adams, J.; Adler, C.; Ahammed, Z.; Allgower, C.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
Fresnel Integral Equations: Numerical Properties
A spatial-domain solution to the problem of electromagnetic scattering from a dielectric half-space is outlined. The resulting half-space operators are referred to as Fresnel surface integral operators. When used as preconditioners for nonplanar geometries, the Fresnel operators yield surface Fresnel integral equations (FIEs) which are stable with respect to dielectric constant, discretization, and frequency. Numerical properties of the formulations are discussed.
Date:
July 22, 2003
Creator:
Adams, R. J.; Champagne, N. J., II & Davis, B. A.
Object Type:
Article
System:
The UNT Digital Library
Orientation for New State WAP Directors and Staff
NASCSP has been providing The Orientation for New Weatherization Assistance Program (WAP) State Directors and Staff yearly for the past four years. This report is a general description of the trainings and supporting documentation from the most recent event. The Orientation and Training provides attendees with a comprehensive overview of the WAP from the federal, state, and local perspectives. A variety of presenters make information available on a wide range of subjects deemed necessary to effectively operate the Program. During the first day of training, staff from the Department of Energy WAP office, NASCSP, the National Energy Assistance Director's Association, Economic Opportunity Studies, and Oak Ridge National Laboratory present materials and participate in open discussion with the attendees about the federal program requirements. Some of the day's subjects include: History of the WAP; Funding, Rules, Regulations, and Program Guidance Documents; WAP State Plan Application Process and Submission; Training and Technical Assistance Activity; Administration and Federal/State Monitoring Requirements; and National Significance of WAP and the Political Process. The second day focuses on implementation strategies for the Program. Presenters from state offices and local management provide their perspective on the following subjects: Utility Restructuring Integration Strategies; Program Expansion Issues; Integration of New …
Date:
April 14, 2003
Creator:
Adams, Robert & Barone, Tracy
Object Type:
Report
System:
The UNT Digital Library
The Development of Mobile Melt-Dilute Technology for the Treatment of Former Soviet Union Research Reactor Fuel
On-site application of the MMD process offers an economical method for converting weapons usable Former Soviet Union (FSU) High Enriched Uranium (HEU) research reactor fuel to a safe and secure Low Enriched Uranium (LEU) ingot. The objective of the MMD Project is to develop the mobile melt and dilute technology in preparation for active equipment deployment in the Newly Independent States (NIS) of the FSU.
Date:
October 9, 2003
Creator:
Adams, T.
Object Type:
Article
System:
The UNT Digital Library
Alternative HEPA Filter Full-Scale Single Element Testing
Conventional disposable glass-fiber high efficiency particulate air (HEPA) filters are used throughout the Department of Energy complex in various process systems. Alternative filter media is being addressed that would have a long life on the HLW tanks.
Date:
January 15, 2003
Creator:
Adamson, D. J.
Object Type:
Report
System:
The UNT Digital Library
Doctoral Recital: 2003-04-14 – Michael Adduci, oboe
Recital presented at the UNT College of Music Recital Hall in partial fulfillment of the Doctor of Musical Arts (DMA) degree.
Date:
April 14, 2003
Creator:
Adduci, Michael
Object Type:
Sound
System:
The UNT Digital Library
Nucleation of GaN/AlN quantum dots
We study the nucleation of GaN islands grown by plasma-assisted molecular-beam epitaxy on AlN in a Stranski-Krastanov mode. In particular, we assess the variation of their height and density as a function of GaN coverage. We show that the GaN growth passes four stages: initially, the growth is layer-by-layer; subsequently, bidimensional precursor islands form, which transform into genuine three-dimensional islands. During the latter stage, the height and the density of the islands increase with GaN coverage until the density saturates. During further GaN growth, the density remains constant and a bimodal height distribution appears. The variation of island height and density as a function of substrate temperature is discussed in the framework of an equilibrium model for Stranski-Krastanov growth [R. E. Rudd et al., Phys. Rev. Lett. 90, 146101 (2003)].
Date:
October 13, 2003
Creator:
Adelmann, C.; Daudin, B.; Oliver, R. A.; Briggs, G. A. D. & Rudd, R. E.
Object Type:
Article
System:
The UNT Digital Library
PRODUCTION WELL PERFORMANCE ENHANCEMENT USING SONICATION TECHNOLOGY
The objective of this project is to develop a sonic well performance enhancement technology that focuses on near wellbore formations. In order to successfully achieve this objective, a three-year project has been defined with each year consisting of four tasks. The first task is the laboratory-scale study whose goal is to determine the underlying principles of the technology. The second task will develop a scale-up mathematical model to serve as the design guide for tool development. The third task is to develop effective transducers that can operate with variable frequency so that the most effective frequencies can be applied in any given situation. The system, assembled as part of the production string, ensures delivery of sufficient sonic energy to penetrate the near-wellbore formation. The last task is the actual field testing of the tool. The first year of the project has been completed.
Date:
December 17, 2003
Creator:
Adewumi, Michael A.; Ityokumbul, M. Thaddeus; Watson, Robert W.; Farias, Mario; Heckman, Glenn; Olanrewaju, Johnson et al.
Object Type:
Report
System:
The UNT Digital Library
DEVELOPMENT OF ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS
Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away from fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of Fe FT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction. The objectives of this research were to develop a better understanding …
Date:
December 1, 2003
Creator:
Adeyiga, Adeyinka A.
Object Type:
Report
System:
The UNT Digital Library
A Binary Segmentation Approach for Boxing Ribosome Particles in Cryo EM Micrographs
Three-dimensional reconstruction of ribosome particles from electron micrographs requires selection of many single-particle images. Roughly 100,000 particles are required to achieve approximately 10 angstrom resolution. Manual selection of particles, by visual observation of the micrographs on a computer screen, is recognized as a bottleneck in automated single particle reconstruction. This paper describes an efficient approach for automated boxing of ribosome particles in micrographs. Use of a fast, anisotropic non-linear reaction-diffusion method to pre-process micrographs and rank-leveling to enhance the contrast between particles and the background, followed by binary and morphological segmentation constitute the core of this technique. Modifying the shape of the particles to facilitate segmentation of individual particles within clusters and boxing the isolated particles is successfully attempted. Tests on a limited number of micrographs have shown that over 80 percent success is achieved in automatic particle picking.
Date:
June 24, 2003
Creator:
Adiga, Umesh P. S.; Malladi, Ravi; Baxter, William & Glaeser, Robert M.
Object Type:
Article
System:
The UNT Digital Library
Extraction of macro-molecule images in cryo-EM micrographs
Advances in Electron Microscopy and single-particle reconstruction have led to results at increasingly high resolutions. This has opened up the possibility of complete automation of single particle reconstruction. Main bottleneck in automation of single particle reconstruction is manual selection of particles in the micrograph. This paper describes a simple but efficient approach for segmentation of particle projections in the micrographs obtained using cryo-electron microscope. Changing the shape of objects to facilitate segmentation from the cluster and reconstructing its actual shape after isolation is successfully attempted. Both low-level and high-level processing techniques are used and the whole process is made automatic. Over 90 percent success in automatic particle picking is achieved. Several areas for improvement and future research directions are discussed.
Date:
March 20, 2003
Creator:
Adiga, Umesha P.S.; Malladi, Ravi & Glaeser, Robert M.
Object Type:
Report
System:
The UNT Digital Library
Deployment of a Continuously Operated {mu}ChemLab
A continuously operating prototype chemical weapons sensor system based on the {mu}ChemLab{trademark} technology was installed in the San Francisco International Airport in late June 2002. This prototype was assembled in a National Electric Manufacturers Association (NEMA) enclosure and controlled by a personal computer collocated with it. Data from the prototype was downloaded regularly and periodic calibration tests were performed through modem-operated control. The instrument was installed just downstream of the return air fans in the return air plenum of a high-use area of a boarding area. A CW Sentry, manufactured by Microsensor Systems, was installed alongside the {mu}ChemLab unit and results from its operation are reported elsewhere. Tests began on June 26, 2002 and concluded on October 16, 2002. This report will discuss the performance of the prototype during the continuous testing period. Over 70,000 test cycles were performed during this period. Data from this first field emplacement have indicated several areas where engineering improvements can be made for future field emplacement.
Date:
May 1, 2003
Creator:
Adkins, Douglas R.; Kottenstette, Richard; Lewis, Patrick R.; Dulleck, George R., Jr.; Oborny, Michael C.; Gordon, Susanna P. et al.
Object Type:
Report
System:
The UNT Digital Library
The Ghanaian Approach to the Development of an Effective Waste Management Regime
In Ghana, radioactive waste is generated mainly from spent sealed sources, various nuclear applications--diagnostic and therapeutic procedures in medicine and measurement and processing techniques in industry. The radionuclide composition in the waste arising from industry, research and teaching includes 14C, 137Cs, 60Co, 241Am, 3H, 32P, 125I, 192Ir, 131I, 99m Tc, 35S and 90Sr. Ghana is strengthening its radioactive waste management infrastructure, which include the development of a legal framework by providing laws, regulations and guidelines and allocating responsibilities of waste generators, the National Radioactive Waste Management Centre (NRWMC), and the Radiation Protection Board (RPB). The radioactive waste management regulations which is in it's final stage of promulgation set up the basic technical and organizational requirements to be complied with by waste generators and operators of waste management facilities and make provisions for penalties for non-compliance with the regulations. With the installation of a 30 kW Research Reactor for neutron activation analysis, 185 TBq 60Co facility for the treatment of cancer at the Korle-bu teaching hospital, 1850 TBq 60Co facility for irradiation of medical and agricultural products and 192Ir sources for industrial radiography, radioactive waste is expected to increase in the near future. At present, waste management is limited exclusively to …
Date:
February 24, 2003
Creator:
Adu, P. S.; Gbadago, J. K. & Glover, E. T.
Object Type:
Article
System:
The UNT Digital Library
Cesium Ion Exchange Using Tank 241-AN-104 Supernate
The River Protection Project is to design and build a high level nuclear waste treatment facility. The waste treatment plant is to process millions of gallons of radioactive waste stored in tanks at the Hanford Site. The high level nuclear waste treatment process includes various unit operations, such as ultrafiltration, precipitation, evaporation, ion exchange, and vitrification. Ion exchange is identified as the optimal treatment method for removal of cesium-137 and Tc-99 from the waste. Extensive ion exchange testing was performed using small-scale columns with actual waste samples. The objectives of this study were to: demonstrate SuperLig 644 ion exchange performance and process steps for the removal of cesium from actual AN-104 tank waste; pretreat actual AN-104 tank waste to reduce the concentration of cesium-137 in the waste below LAW vitrification limit; produce and characterize cesium eluate solutions for use in eluate evaporation tests. The experiments consisted of batch contact and small-scale column tests. The batch contact tests measured sorption partition coefficients Kds. The Kds were used to predict the effective resin capacity. The small-scale column tests, which closely mimic plant conditions, generated loading and elution profile data used to determine whether removal targets and design requirements were met.
Date:
December 22, 2003
Creator:
Adu-Wusu, K.
Object Type:
Report
System:
The UNT Digital Library
Evaluating the Effects of Tri-Butyl Phosphate and Normal Paraffin Hydrocarbon in Simulated Low-Activity Waste Solution on Ion Exchange
Ultrafiltration and ion exchange are among the pretreatment processes selected for the WTP at the Hanford Site. This study is the second part of a two-part study on Evaluating the Effects of Tri-Butyl Phosphate and Normal Paraffin Hydrocarbon in Simulated Low-Activity Waste Solution on Ultrafiltration and Ion Exchange.
Date:
May 13, 2003
Creator:
Adu-Wusu, K.
Object Type:
Report
System:
The UNT Digital Library
Proteomics: Technology and Applications
This meeting took place at the Keystone, Colorado resort from March 25-30, 2003. It was attended by 206 participants, of which 35 were students; 39% of attendees submitted abstracts. The meeting had 30% returning attendees and 70% new attendees. The group of speakers was composed of internationally recruited junior and senior experts in their respective fields. The group included representatives from academia and the private sector, highlights the convergence of proteomics efforts in the two sectors. The completion of the genome sequences of a large number of prokaryotic and eukaryotic species has catalyzed new research approaches to study the structure, function and control of biological processes. They are characterized by the systematic and in many cases quantitative analysis of all the molecules of a particular type expressed by a cell or tissue. The systematic analysis of proteins has been terms ''proteomics''. In an initial phase, most of the proteomics efforts were focused on large-scale protein identification. More recently, the objectives and technologies of proteomics have been diversified and expanded. Current proteomics research attempts to systematically and, where applicable, quantitatively determine the many properties of proteins and their biological function, including: protein abundance, state of modification, specific activity, interaction with other …
Date:
March 25, 2003
Creator:
Aebersold, Ruedi
Object Type:
Report
System:
The UNT Digital Library