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Serial/Series Title
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Day
The CDF Run IIa Silicon Detector and Its Upgrade RunIIb
The CDF RunIIa silicon detector made the transition from commissioning to data taking. CDF's online and offline tracking algorithms, the performance of Layer 00 and the RunIIb silicon upgrade project are covered in this article.
Date:
December 19, 2003
Creator:
Issever, Cigdem
Object Type:
Article
System:
The UNT Digital Library
IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems
With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration/Heat Recovery Systems) under the ''IEA Implementing Agreement on Heat Pumping Technologies''. Annex 26 focuses on demonstrating and documenting the energy saving and environmental benefits of advanced systems design for food refrigeration and space heating and cooling for supermarkets. Advanced in this context means systems that use less energy, require less refrigerant and produce lower refrigerant emissions. Stated another way, the goal is to identify supermarket refrigeration and HVAC technology options that reduce the total equivalent warming impact (TEWI) of supermarkets by reducing both system energy use (increasing efficiency) and reducing total refrigerant charge. The Annex has five participating countries: Canada, Denmark, Sweden, the United Kingdom, and the United States. The working program of the Annex has involved analytical and experimental investigation of several candidate system design approaches to determine their potential to reduce refrigerant usage and energy consumption. Advanced refrigeration system …
Date:
May 19, 2003
Creator:
Baxter, VAN
Object Type:
Report
System:
The UNT Digital Library
Hera Beam Tail Shaping by Tune Modulation.
To study CP violation, the HEM-B experiment uses an internal wire target in the transverse halo of the stored HERA proton beam. Operational experience shows that the resulting interaction rates are extremely sensitive to tiny orbit jitter amplitudes. Various methods have been studied to stabilize these interaction rates by increasing diffusion in the transverse proton beam tails without affecting the luminosity at the electron-proton collider experiments ZEUS and H1. Tune modulation was found to be a promising method for this task. Experiments performed in recent years will be reported.
Date:
May 19, 2003
Creator:
Montag, C.
Object Type:
Article
System:
The UNT Digital Library
Final Scientific Report DE-FGO3-97ER62460 Stomatal Responses to CO2: A Comparison of Woody and Herbaceous Species in Arid and Humid Climates
OAK-B135 The project involved a study of a fundamental response of terrestrial vegetation to rising atmospheric carbon dioxide (CO2) concentration, namely, the change in leaf conductance to gas diffusion associated with a change in the aperture of the microscopic pores (stomata) on the surface of leaves.
Date:
December 19, 2003
Creator:
Koch, George W.
Object Type:
Report
System:
The UNT Digital Library
Rheology Modifiers for Radioactive Waste Slurries
The goals of this study were to determine if trace levels of chemical additives could be used to reduce the rheological characteristics of radioactive waste slurries, identify potential chemical additives for this work and future testing, test a limited set of chemical additive candidates on simulated radioactive wastes, and develop advanced techniques to visualize the internal slurry structure and particle-particle interaction within the slurry.
Date:
February 19, 2003
Creator:
Calloway, T.B. Jr.
Object Type:
Article
System:
The UNT Digital Library
Lithium-Based Electrochromic Mirrors
Antimony, antimony-copper, and antimony-silver thin films were prepared by DC magnetron sputtering on glass substrates. Their reflectance and transmittance in the visible range were measured before and after electrochemical lithiation. The mixed metal films exhibited larger changes in reflectance and small shifts in the optical absorption edge compared with pure antimony films. Electrochromic cycling speed and stability of the Sb-Li system were improved by the addition of copper and silver.
Date:
May 19, 2003
Creator:
Richardson, Thomas J. & Slack, Jonathan L.
Object Type:
Article
System:
The UNT Digital Library
Enhancing the Atomic-Level Understanding of co2 Mineral Sequestration Mechanisms via Advanced Computational Modeling
Fossil fuels currently provide 85% of the world's energy needs, with the majority coming from coal, due to its low cost, wide availability, and high energy content. The extensive use of coal-fired power assumes that the resulting CO{sub 2} emissions can be vented to the atmosphere. However, exponentially increasing atmospheric CO{sub 2} levels have brought this assumption under critical review. Over the last decade, this discussion has evolved from whether exponentially increasing anthropogenic CO{sub 2} emissions will adversely affect the global environment, to the timing and magnitude of their impact. A variety of sequestration technologies are being explored to mitigate CO{sub 2} emissions. These technologies must be both environmentally benign and economically viable. Mineral carbonation is an attractive candidate technology as it disposes of CO{sub 2} as geologically stable, environmentally benign mineral carbonates, clearly satisfying the first criteria. The primary challenge for mineral carbonation is cost-competitive process development. CO{sub 2} mineral sequestration--the conversion of stationary-source CO{sub 2} emissions into mineral carbonates (e.g., magnesium and calcium carbonate, MgCO{sub 3} and CaCO{sub 3})--has recently emerged as one of the most promising sequestration options, providing permanent CO{sub 2} disposal, rather than storage. In this approach a magnesium-bearing feedstock mineral (typically serpentine or olivine; …
Date:
December 19, 2003
Creator:
Chizmeshya, A. V. G.
Object Type:
Report
System:
The UNT Digital Library
Effective theory approach to unstable particles
The authors present a novel treatment of resonant massive particles appearing as intermediate states in high energy collisions. The approach uses effective field theory methods to treat consistently the instability of the intermediate resonant state. As a result gauge invariance is respected in every step and calculations can in principle be extended to all orders in perturbation theory, the only practical limitation in going to higher orders being the standard difficulties related to multi-loop integrals. The authors believe that the longstanding problem related to the treatment of instability of particles is now solved.
Date:
May 19, 2003
Creator:
Zanderighi, Giulia
Object Type:
Article
System:
The UNT Digital Library
Effect of surface carbon structure on the electrochemical performance of LiFePO{sub 4}
None
Date:
February 19, 2003
Creator:
Doeff, Marca M.; Hu, Yaoqin; McLarnon, Frank & Kostecki, Robert
Object Type:
Article
System:
The UNT Digital Library
Scattering of slow electrons by polar molecules: Application of effective-range potential theory to HC1
We present a non-empirical potential model for studying threshold vibrational excitation of polar molecules by electron impact. This work builds on the zero-range potential virtual state model of Gauyacq and Herzenberg (J.P. Gauyacq and A. Herzenberg, Phys. Rev. A 25, 2959 (1982)), using known analytic properties of the S-matrix for a dipole potential to predict the analytic continuation of the negative ion potential curve into the continuum. We derive an equation that determines the nuclear dynamics which can be solved without the need for an expansion in target vibrational states. The model is applied to e{sup -} - HCl and is found to capture the essential features of the observed excitation cross sections, including both the threshold peaks as well as oscillatory structures at energies above threshold.
Date:
June 19, 2003
Creator:
Vanroose, Wim; McCurdy, C. W. & Rescigno, T. N.
Object Type:
Article
System:
The UNT Digital Library
Three-Dimensional Neutral Transport Simulations of Gas Puff Imaging Experiments
Gas Puff Imaging (GPI) experiments are designed to isolate the structure of plasma turbulence in the plane perpendicular to the magnetic field. Three-dimensional aspects of this diagnostic technique as used on the National Spherical Torus eXperiment (NSTX) are examined via Monte Carlo neutral transport simulations. The radial width of the simulated GPI images are in rough agreement with observations. However, the simulated emission clouds are angled approximately 15 degrees with respect to the experimental images. The simulations indicate that the finite extent of the gas puff along the viewing direction does not significantly degrade the radial resolution of the diagnostic. These simulations also yield effective neutral density data that can be used in an approximate attempt to infer two-dimensional electron density and temperature profiles from the experimental images.
Date:
September 19, 2003
Creator:
Stotler, D. P.; DIppolito, D. A.; LeBlanc, B.; Maqueda, R. J.; Myra, J. R.; Sabbagh, S. A. et al.
Object Type:
Report
System:
The UNT Digital Library
Development of Compact Quasi-Axisymmetric Stellarator Reactor Configurations
We have started to examine the reactor potential of quasi-axisymmetric (QA) stellarators with an integrated approach that includes systems evaluation, engineering considerations, and plasma and coil optimizations. In this paper, we summarize the progress made so far in developing QA configurations with reduced alpha losses while retaining good MHD stability properties. The minimization of alpha losses is achieved by directly targeting the collisionless orbits to prolong the average resident times. Configurations with an overall energy loss rate of {approx}10% or less, including collisional contributions, have been found. To allow remotely maintaining coils and machine components in a reactor environment, there is a desire to simplify to the extent possible the coil design. To this end, finding a configuration that is optimized not only for the alpha confinement and MHD stability but also for the good coil and reactor performance, remains to be a challenging task.
Date:
September 19, 2003
Creator:
Ku, L. P.; Zarnstorff, M.; White, R. B.; Cooper, W. A.; Sanchez, R.; Neilson, H. et al.
Object Type:
Report
System:
The UNT Digital Library
Improved Conservation Properties for Particle-in-cell Simulations with Kinetic Electrons
It is shown that a simple algorithm which exactly segregates between adiabatic and non-adiabatic electrons in particle-in-cell simulations of drift modes yields excellent conservation properties (e.g. particle number, energy) compared to the conventional df scheme. The removal of the free streaming term in the evolution of the marker weight is shown to be responsible for the improved linear and nonlinear properties of the simulated plasma.
Date:
June 19, 2003
Creator:
Lewandowski, J.L.V.
Object Type:
Report
System:
The UNT Digital Library
Melt Rate Testing for the DWPF: Summary of FY02 Testing
A study performed in FY01 recommended that the Defense Waste Process Facility (DWPF) replace Frit 200 with Frit 320 for the processing of sludge batch 2 (SB2) to improve melt rate (Lambent et al., 2001) contingent upon additional testing which included slurry feeding. The FY02 melt rate program was developed to support this recommendation as well as to investigate alternative methods of improving melt rate above and beyond a change in frit composition. The integrated program was primarily based on a sound testing methodology from which the frit change was recommended. In addition, the program included the development of additional tools to provide further insight into melt rate enhancements. The overall strategy of the FY02 testing program was to design suites of melt rate tests based on recommendations from previous work that provided insight into other methods of improving melt rate for the DWPF. The objectives of the FY02 testing program included how melt rate might be influenced by increases in waste loading, differences in frit particle size, the use of batch chemicals rather than a pre-fabricated frit, and the impact of uranium. This report summarizes the equipment development and setup, procedures, and results of this testing, and includes recommendations …
Date:
February 19, 2003
Creator:
Lorier, T.H.
Object Type:
Report
System:
The UNT Digital Library
HANFORD TANK FARM CONTRACTOR SELF ASSESSMENT PROGRAM
None
Date:
November 19, 2003
Creator:
AROMI, E.S. & ANDERSON, C.E.
Object Type:
Report
System:
The UNT Digital Library
Self-Consistent System of Equations for a Kinetic Description of the Low-Pressure Discharges Accounting for the Nonlocal and Collisionless Electron Dynamics
In low-pressure discharges, when the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially non-local. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the non-local conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study a self-consistent system of equations for the kinetic description of nonlocal, non-uniform, nearly collisionless plasmas of low-pressure discharges is derived. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. The importance of accounting for the non-uniform plasma density profile on both the current density profile and the EEDF is demonstrated.
Date:
May 19, 2003
Creator:
Kaganovich, Igor D. & Polomarov, Oleg
Object Type:
Report
System:
The UNT Digital Library
Cold asymmetrical fermion superfluids
The recent experimental advances in cold atomic traps have induced a great amount of interest in fields from condensed matter to particle physics, including approaches and prospects from the theoretical point of view. In this work we investigate the general properties and the ground state of an asymmetrical dilute gas of cold fermionic atoms, formed by two particle species having different densities. We have show in a recent paper, that a mixed phase composed of normal and superfluid components is the energetically favored ground state of such a cold fermionic system. Here we extend the analysis and verify that in fact, the mixed phase is the preferred ground state of an asymmetrical superfluid in various situations. We predict that the mixed phase can serve as a way of detecting superfluidity and estimating the magnitude of the gap parameter in asymmetrical fermionic systems.
Date:
December 19, 2003
Creator:
Caldas, Heron
Object Type:
Article
System:
The UNT Digital Library
Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes
The report describes progress made in the various thrust areas of the project, which include internal drives for oil recovery, vapor-liquid flows, combustion and reaction processes and the flow of fluids with yield stress.
Date:
March 19, 2003
Creator:
Yorstos, Yannis C.
Object Type:
Report
System:
The UNT Digital Library
Testing of the TriP Chip Running at 132 nsec Using a Modified AFE Board
In this note we describe the first set of tests done with a sample of TriP chips that were mounted on a modified AFE board. The modifications consisted of different firmware and the replacement of one power supply switch. The board used was a standard AFEIc board (red type) on which new MCMs (MCMIIs) were mounted. The new MCMs were designed to support the TriP and emulate the SVX for readout when mounted on an AFEIc board. The TriP and the MCMs are described in Ref. [1]. Two versions of the MCMII were designed and built: one (MCMIIb) supports two TriP chips wirebonded directly to the MCM substrate. The other, (MCMIIc) supports one TriP which can be either wirebonded directly or packaged into a standard TQFP surface mount package. Due to space constraints, this MCM can support only 1 TriP. We tested 6 TriP chips on 3 different MCMIIb (MCMIIb-1, MCMIIb-2 and MCMIIb-3) and 2 other TriPs were tested on MCMIIc, one of them with an unpackaged TriP (MCMIIc-1) and the other with a packaged TriP (MCMIIc-2). A set of 10 programable internal registers control the TriP operation, the description of these registers can be found in [1]. Table 1 …
Date:
December 19, 2003
Creator:
al., Juan Estrada et
Object Type:
Report
System:
The UNT Digital Library
QUANTIFICATION OF MERCURY IN FLUE GAS EMISSION USING BORON-DOPED DIAMOND ELECTROCHEMISTRY
In this project, we have attempted to develop a new technique utilizing Boron-doped diamond (BDD) films to electrochemically detect mercury dissolved in solution via the initial deposition of metallic mercury, followed by anodic linear sweep voltammetry in the range from 10-10{sup -10} M to 10{sup -5} M. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were employed. The extremely low background current for BDD electrodes compared to glassy carbon (GC) provides a strong advantage in trace metal detection. CV peak currents showed good linearity in the micromolar range. A detection level of 6.8 x 10{sup -10} M was achieved with DPV in 0.1 M KNO{sub 3} (pH = 1) for a deposition time of 20 minutes. Reproducible stripping peaks were obtained, even for the low concentration range. A comparison with GC shows that BDD is superior. Linear behavior was also obtained in the mercury concentration range from 10{sup -10} M to 10{sup -9} M.
Date:
August 19, 2003
Creator:
Manivannan, A. & Seehra, M.S.
Object Type:
Report
System:
The UNT Digital Library
Observations of Anisotropic Ion Temperature during RF Heating in the NSTX Edge
A new spectroscopic diagnostic on the National Spherical Torus Experiment (NSTX) measures the velocity distribution of ions in the plasma edge with both poloidal and toroidal views. An anisotropic ion temperature is measured during the presence of high power HHFW RF heating in He plasmas, with the poloidal T(sub)i roughly twice the toroidal T(sub)i. Moreover, the measured spectral distribution suggests that two populations have temperatures of 500 eV and 50 eV with rotation velocities of -50 km/s and -10 km/s, respectively. This bi-modal distribution is observed in both the toroidal and poloidal views (in both He II and C III ions), and is well correlated with the period of RF power application to the plasma. The temperature of the edge ions is observed to increase with the applied RF power, which was scanned between 0 and 4.3MW. The ion heating mechanism from HHFW RF power has not yet been identified.
Date:
May 19, 2003
Creator:
Biewer, T. M.; Bell, R. E.; Darrow, D. S.; Phillips, C. K. & Wilson, J. R.
Object Type:
Report
System:
The UNT Digital Library
Evaluation of slurry injection technology for management of drilling wastes.
Each year, thousands of new oil and gas wells are drilled in the United States and around the world. The drilling process generates millions of barrels of drilling waste each year, primarily used drilling fluids (also known as muds) and drill cuttings. The drilling wastes from most onshore U.S. wells are disposed of by removing the liquids from the drilling or reserve pits and then burying the remaining solids in place (called pit burial). This practice has low cost and the approval of most regulatory agencies. However, there are some environmental settings in which pit burial is not allowed, such as areas with high water tables. In the U.S. offshore environment, many water-based and synthetic-based muds and cuttings can be discharged to the ocean if discharge permit requirements are met, but oil-based muds cannot be discharged at all. At some offshore facilities, drilling wastes must be either hauled back to shore for disposal or disposed of onsite through an injection process.
Date:
February 19, 2003
Creator:
Veil, J. A. & Dusseault, M. B.
Object Type:
Report
System:
The UNT Digital Library
Time-of-flight measurement in the DZero Central Fiber Tracker
We continue evaluation of the new electronics developed for the Central Fiber Tracker and Preshower detectors. With the custom TriP chip and MCM II we have measured the position of the hits along the fiber by comparing the time of arrival of the photons at the VLPC with the expected timing relative to the beam. The measured rms resolution at the center of the fibers is 46cm for hits with more than 8 photo-electrons and is dominated by the statistics of photon arrival time. The corresponding resolution near the ends of the fibers (where more photoelectrons are collected) is calculated to be of order 27cm. With a second submission of the TriP chip to add the time-of-flight measuring capability we will effectively double the number of channels in the central fiber tracker. This capability will increase the maximum luminosity at which D0 can do tracking from {approx} 100 {center_dot} 10{sup 30}cm{sup -2}s{sup -1} to {approx} 200 {center_dot} 10{sup 30} cm{sup -2}s{sup -1} (at a bench mark tracking specification). The cost of replacing the electronics is of order $500K and the necessary lead time is 1.5 years.
Date:
December 19, 2003
Creator:
al., Juan Estrada et
Object Type:
Report
System:
The UNT Digital Library
Private Appropriation, Public Dissemination and Commercial Product Development in Genomics (DOE)
With DOE funding, I have conducted research on the topic of patents and technology transfer in the Human Genome Project since 1994. My research has proceeded along the following tracks: (1) research and monitoring of legal developments relating to (a) the patenting of DNA sequences and (b) the role of patents in technology transfer; (2) investigating and monitoring the strategies of different institutions in the public and private sector that are involved in DNA sequencing with respect to patenting and disseminating sequence information; (3) investigating and monitoring the impact of these strategies on those who use sequence information in research and product development. I have published commentary as my research proceeds in a variety of forums directed at scientists, lawyers, and science policy-makers.
Date:
March 19, 2003
Creator:
Eisenberg, Rebecca S.
Object Type:
Report
System:
The UNT Digital Library