States

The three-point function as a probe of models for large-scale structure (open access)

The three-point function as a probe of models for large-scale structure

The authors analyze the consequences of models of structure formation for higher-order (n-point) galaxy correlation functions in the mildly non-linear regime. Several variations of the standard [Omega] = 1 cold dark matter model with scale-invariant primordial perturbations have recently been introduced to obtain more power on large scales, R[sub p] [approximately]20 h[sup [minus]1] Mpc, e.g., low-matter-density (non-zero cosmological constant) models, [open quote]tilted[close quote] primordial spectra, and scenarios with a mixture of cold and hot dark matter. They also include models with an effective scale-dependent bias, such as the cooperative galaxy formation scenario of Bower, et al. The authors show that higher-order (n-point) galaxy correlation functions can provide a useful test of such models and can discriminate between models with true large-scale power in the density field and those where the galaxy power arises from scale-dependent bias: a bias with rapid scale-dependence leads to a dramatic decrease of the hierarchical amplitudes Q[sub J] at large scales, r [approx gt] R[sub p]. Current observational constraints on the three-point amplitudes Q[sub 3] and S[sub 3] can place limits on the bias parameter(s) and appear to disfavor, but not yet rule out, the hypothesis that scale-dependent bias is responsible for the extra power observed …
Date: June 19, 1993
Creator: Frieman, J.A. (Fermi National Accelerator Lab., Batavia, IL (United States)) & Gaztanaga, E. (Univ. of Oxford (United Kingdom))
Object Type: Report
System: The UNT Digital Library
[Transformation toughening] (open access)

[Transformation toughening]

In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite transformation in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive transformation were used in simulating the transformation near a crack tip under Mode I loading; the transformation pattern and toughening are different from standard transformation toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic transformation in a polycrystalline sample of NiAl was simulated. In the ZrO[sub 2] system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic transformations have been started by doing a more elaborate total energy calculation.In the Al[sub 2]0[sub 3] system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.
Date: April 19, 1993
Creator: Rafa, M.J.
Object Type: Report
System: The UNT Digital Library
Midpoint technical report (open access)

Midpoint technical report

The research covers high-resolution imaging of electrical conductivity using low-frequency electromagnetic fields. This report contains two appendices: progress made in optimizing a 3D integral equations forward modeling code for imaging, and a technique for improving the resolution of the inverse problem.
Date: April 19, 1993
Creator: Tripp, A. C.
Object Type: Report
System: The UNT Digital Library
Texas Register, Volume 18, Number 6, Pages 339-381, January 19, 1993 (open access)

Texas Register, Volume 18, Number 6, Pages 339-381, January 19, 1993

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: January 19, 1993
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 18, Number 14, Pages 1057-1111, February 19, 1993 (open access)

Texas Register, Volume 18, Number 14, Pages 1057-1111, February 19, 1993

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: February 19, 1993
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 18, Number 22, Pages 1783-1825, March 19, 1993 (open access)

Texas Register, Volume 18, Number 22, Pages 1783-1825, March 19, 1993

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: March 19, 1993
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 18, Number [79], Pages 7211-7313, October 19, 1993 (open access)

Texas Register, Volume 18, Number [79], Pages 7211-7313, October 19, 1993

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: October 19, 1993
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Texas Register, Volume 18, Number 87, Pages 8477-8625, November 19, 1993 (open access)

Texas Register, Volume 18, Number 87, Pages 8477-8625, November 19, 1993

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: November 19, 1993
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Laser flash photolysis, EPR and raman studies of liquids at elevated pressures. Progress report, April 1, 1993--November 19, 1993 (open access)

Laser flash photolysis, EPR and raman studies of liquids at elevated pressures. Progress report, April 1, 1993--November 19, 1993

A laser flash photolysis kinetic study of a W(CO){sub 5} intermediate reacting with several different substituted 2,2{prime}-bipyridine ligands at pressures up to 150 MPa in liquid toluene has confirmed the considerable influence of steric hindrance on the mechanism of a thermal ring closure reaction. A similar laser flash photolysis kinetic study has been carried out with Mo(CO){sub 6} and several bidentate ligands resembling 2,2{prime}-bipyridine dissolved in supercritical carbon dioxide. A much larger negative activation volume is found in supercritical carbon dioxide than observed previously with this solute system dissolved in liquid toluene. Rate of replacement of one polydentate ligand by another stronger chelating agent in the first coordination sphere of aqueous gadolinium(III) ion was measured over a range of pressures and other variables using a stopped-flow spectrophotometer. Two consecutive first order reaction steps are observed that show acid-catalysis.
Date: November 19, 1993
Creator: Eyring, E. M.
Object Type: Report
System: The UNT Digital Library
Effect of boron and hydrogen on the electronic structure of Ni{sub 3}Al (open access)

Effect of boron and hydrogen on the electronic structure of Ni{sub 3}Al

Using first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial born and hydrogen on the electronic structure of the Ll{sub 2} ordered intermetallic Ni{sub 3}Al. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound ``pure`` Ni{sub 3}Al crystal: Charge is depleted at Ni and Al region. Substitution Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.
Date: November 19, 1993
Creator: Kioussi, N.; Watanabe, H.; Hemker, R. G.; Gourdin, W.: Gonis, A. & Johnson, P. E.
Object Type: Article
System: The UNT Digital Library
Midpoint technical report (open access)

Midpoint technical report

The research covers high-resolution imaging of electrical conductivity using low-frequency electromagnetic fields. This report contains two appendices: progress made in optimizing a 3D integral equations forward modeling code for imaging, and a technique for improving the resolution of the inverse problem.
Date: April 19, 1993
Creator: Tripp, A. C.
Object Type: Report
System: The UNT Digital Library
[Transformation toughening]. Annual progress report (open access)

[Transformation toughening]. Annual progress report

In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite transformation in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive transformation were used in simulating the transformation near a crack tip under Mode I loading; the transformation pattern and toughening are different from standard transformation toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic transformation in a polycrystalline sample of NiAl was simulated. In the ZrO{sub 2} system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic transformations have been started by doing a more elaborate total energy calculation.In the Al{sub 2}0{sub 3} system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.
Date: April 19, 1993
Creator: Rafa, M. J.
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: DM-264 (open access)

Texas Attorney General Opinion: DM-264

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Dan Morales, regarding a legal question submitted for clarification; Whether the Denton County Bail Bond Board is authorized to set a limit on the value amount of bonds which a corporate surety may provide, and related questions under article 2372p-3 V.T.C.S. (RQ-191)
Date: October 19, 1993
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: LO93-093 (open access)

Texas Attorney General Opinion: LO93-093

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Dan Morales, regarding a legal question submitted for clarification: Whether an independent school district may award scholarships out of its general fund to its top graduates based solely on academic ranking (RQ-601)
Date: October 19, 1993
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Radiative corrections in the strongly interacting limit of the standard electroweak model (open access)

Radiative corrections in the strongly interacting limit of the standard electroweak model

Radiative corrections to the parameters of the standard electroweak model are considered in case that there is no light Higgs particle.
Date: April 19, 1993
Creator: Gaillard, M. K.
Object Type: Article
System: The UNT Digital Library
Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-third quarterly status report, April--June 1993 (open access)

Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-third quarterly status report, April--June 1993

The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: A baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.
Date: July 19, 1993
Creator: Newby, R. A.; Alvin, M. A.; Bachovchin, D. M.; Yang, W. C.; Smeltzer, E. E. & Lippert, T. E.
Object Type: Report
System: The UNT Digital Library
X-ray laser `` oscillator-amplifier`` experiments (open access)

X-ray laser `` oscillator-amplifier`` experiments

We present results from experiments directed toward increasing the degree of transverse coherence in x-ray laser beams. We have concentrated on the neon-like yttrium (Z=39) collisionally-pumped x-ray laser as the test system for these studies because of its unique combination of brightness, monochromaticity, and high-reflectivity optics availability. Attempts at improving laser performance using proximate feedback optics failed. Modest success has been found to date in ``double foil`` experiments, involving two x-ray lasers spatially separated by 29 cm and shot sequentially in an ``oscillator-amplifier`` configuration.
Date: March 19, 1993
Creator: Shimkaveg, G. M.; Carter, M. R.; Young, B. K. F.; Walling, R. S.; Osterheld, A. L.; Trebes, J. E. et al.
Object Type: Article
System: The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning. Final report (open access)

Control of pyrite surface chemistry in physical coal cleaning. Final report

In Part I, Surface Chemistry of Coal Pyrite the mechanisms responsible for the inefficient rejection of coal pyrite were investigated using a number of experimental techniques. The test results demonstrate that the hydrophobicity of coal pyrite is related to the surface products formed during oxidation in aqueous solutions. During oxidation, a sulfur-rich surface layer is produced in near neutral pH solutions. This surface layer is composed mainly of sulfur species in the form of an iron-polysulfide along with a smaller amount of iron oxide/hydroxides. The floatability coal pyrite increases dramatically in the presence of frothers and hydrocarbon collectors. These reagents are believed to absorb on the weakly hydrophobic pyrite surfaces as a result of hydrophobic interaction forces. In Part III, Developing the Best Possible Rejection Schemes, a number of pyrite depressants were evaluated in column and conventional flotation tests. These included manganese (Mn) metal, chelating agents quinone and diethylenetriamine (DETA), and several commercially-available organic depressants. Of these, the additives which serve as reducing agents were found to be most effective. Reducing agents were used to prevent pyrite oxidation and/or remove oxidation products present on previously oxidized surfaces. These data show that Mn is a significantly stronger depressant for pyrite than …
Date: May 19, 1993
Creator: Luttrell, G. H.; Yoon, R. H. & Richardson, P. E.
Object Type: Report
System: The UNT Digital Library
Weak neutral currents and collapse initiated supernova (open access)

Weak neutral currents and collapse initiated supernova

Since 1974 the neutrino processes mediated by neutral currents have been a part of supernova (SN) modeling calculations. In this report only present day SN calculations will be discussed. First I will give brief description of the SN computer model and an outline of the explosion process as depicted by that model. Then I will discuss the role weak neutral current (WNC) processes play in this explosion process. Finally, I will discus inelastic scattering of tau neutrinos by heavy elements in WNC or Earth as a mechanism for measuring the mass of tau neutrino.
Date: March 19, 1993
Creator: Wilson, J. R.
Object Type: Article
System: The UNT Digital Library
The three-point function as a probe of models for large-scale structure (open access)

The three-point function as a probe of models for large-scale structure

The authors analyze the consequences of models of structure formation for higher-order (n-point) galaxy correlation functions in the mildly non-linear regime. Several variations of the standard {Omega} = 1 cold dark matter model with scale-invariant primordial perturbations have recently been introduced to obtain more power on large scales, R{sub p} {approximately}20 h{sup {minus}1} Mpc, e.g., low-matter-density (non-zero cosmological constant) models, {open_quote}tilted{close_quote} primordial spectra, and scenarios with a mixture of cold and hot dark matter. They also include models with an effective scale-dependent bias, such as the cooperative galaxy formation scenario of Bower, et al. The authors show that higher-order (n-point) galaxy correlation functions can provide a useful test of such models and can discriminate between models with true large-scale power in the density field and those where the galaxy power arises from scale-dependent bias: a bias with rapid scale-dependence leads to a dramatic decrease of the hierarchical amplitudes Q{sub J} at large scales, r {approx_gt} R{sub p}. Current observational constraints on the three-point amplitudes Q{sub 3} and S{sub 3} can place limits on the bias parameter(s) and appear to disfavor, but not yet rule out, the hypothesis that scale-dependent bias is responsible for the extra power observed on large scales.
Date: June 19, 1993
Creator: Frieman, J. A. & Gaztanaga, E.
Object Type: Report
System: The UNT Digital Library
Older muons are wiser: Using time information in {mu}LCR spectroscopy (open access)

Older muons are wiser: Using time information in {mu}LCR spectroscopy

For {mu}LCR with slow polarization transfer, the weak resonance signals can be strengthened by delaying the positron observation period, for pulsed and chopped muon beams. Furthermore, the sensitivity to drifts can be reduced or eliminated by using the ratios of late to early e{sup +} counts. These possibilities for using time information are discussed quantitatively.
Date: May 19, 1993
Creator: Leon, M.
Object Type: Article
System: The UNT Digital Library
A lower cost development path for heavy ion fusion (open access)

A lower cost development path for heavy ion fusion

If two features of the inertial fusion process are exploited successfully, they can lead to significantly lower costs for demonstrating the feasibility of commercial electric power production from this source of energy. First, fusion capsule ignition and burn physics is independent of reaction chamber size and hydrodynamically-equivalent capsules can be designed to perform at small yield, exactly as they do at large yield. This means that an integrated test of all power plant components and feasibility tests of various reaction chamber concepts can be done at much smaller sizes (about 1--2 m first wall radius) and much lower powers (tens of MWs) than magnetic fusion development facilities such as ITER. Second, the driver, which is the most expensive component of currently conceived IFE development facilities, can be used to support more than one experiment target chamber/reactor (simultaneously and/or sequentially). These two factors lead to lower development facility costs, modular facilities, and the planning flexibility to spread costs over time or do several things in parallel and thus shorten the total time needed for development of Inertial Fusion Energy (IFE). In this paper the authors describe the general feature of a heavy ion fusion development plan that takes advantage of upgradable …
Date: May 19, 1993
Creator: Hogan, W. J. & Meier, W. R.
Object Type: Article
System: The UNT Digital Library
Advanced, soluble hydroliquefaction and hydrotreating catalysts. Quarterly reports No. 10 and 11, January 1, 1993--May 30, 1993 (open access)

Advanced, soluble hydroliquefaction and hydrotreating catalysts. Quarterly reports No. 10 and 11, January 1, 1993--May 30, 1993

The purpose of the present program is to develop soluble analogs of surface confined catalysts that can be impregnated directly into the coal structure at low temperatures. This approach should avoid problems related to surface area dependence, a two phase (surface-liquid) reaction system and, mass transport limitations. Heteropolyanions (HPAs) offer the opportunity to develop soluble forms of surface confined catalysts. HPAs, are inexpensive, well-characterized, water soluble metal oxide clusters, e.g. [EM {sub 12}O{sub 40}]{sup 14{minus}} where E = Si or P and M = Mo or W. They are easily modified to contain other transition metals such as Co, Ni or Ru and, can be made soluble in organic solvents. The protic forms exhibit extremely high acidities pK{sub a} {approx} 0--2. In addition, selectively modified RPAs can function as low temperature hydrogenation catalysts that exhibit microporosity HPAs are multifunctional catalysts that could be used to promote both hydroliquefaction and hydrotreating. In theory, these functions could be employed sequentially or simultaneously and could permit exceptional control of liquefaction reactions and reaction conditions. Thus, the current research program involves efforts to evaluate HPAs as soluble liquefaction and hydrotreating catalysts, with the goal of developing soluble analogs of surface confined catalysts. Alternately, if …
Date: May 19, 1993
Creator: Laine, R. M. & Stoebe, T.
Object Type: Report
System: The UNT Digital Library
Modeling the response of ecosystems to CO{sub 2} and climate change. Progress report, September 1, 1992--June 19, 1993 (open access)

Modeling the response of ecosystems to CO{sub 2} and climate change. Progress report, September 1, 1992--June 19, 1993

In recognition of the role of plants in the bio-geosphere carbon cycle, the Department of Energy (OHER) initiated a research program: The Direct Effects of Increasing Carbon Dioxide on Vegetation. This report describes the continuing research that we are conducting as part of this program. The ultimate goal of our research is to develop computer models capable of predicting responses of plants and ecosystems to the direct and indirect effects of atmospheric levels of carbon dioxide that are approximately twice those of the preindustrial period. The understanding of ecosystem responses to elevated CO{sub 2} necessarily depends on knowledge of responses of individual plants and their interactions with one another and their environment Our research approach incorporates the study and modeling of response to CO{sub 2} at all levels of the plant-community-ecosystem hierarchy, in an effort to understand the linkages and translation of effects of CO{sub 2} from one level to another. The research results reported here focus at several different levels of this hierarchy, and are highlights of accomplishments for the period September 1992 to June 1993.
Date: June 19, 1993
Creator: Reynolds, J. F.; Kemp, P. R. & Chen, J.
Object Type: Report
System: The UNT Digital Library