PREDICTION OF THERMODYNAMIC PROPERTIES OF COMPLEX FLUIDS (open access)

PREDICTION OF THERMODYNAMIC PROPERTIES OF COMPLEX FLUIDS

ABSTRACT The goal of this research has been to generalize Density Functional Theory (DFT) for complex molecules, i.e. molecules whose size, shape, and interaction energies cause them to show significant deviations from mean-field behavior. We considered free energy functionals and minimized them for systems with different geometries and dimensionalities including confined fluids (such as molecular layers on surfaces and molecules in nano-scale pores), systems with directional interactions and order-disorder transitions, amphiphilic dimers, block copolymers, and self-assembled nano-structures. The results of this procedure include equations of equilibrium for these systems and the development of computational tools for predicting phase transitions and self-assembly in complex fluids. DFT was developed for confined fluids. A new phenomenon, surface compression of confined fluids, was predicted theoretically and confirmed by existing experimental data and by simulations. The strong attraction to a surface causes adsorbate molecules to attain much higher densities than that of a normal liquid. Under these conditions, adsorbate molecules are so compressed that they repel each other. This phenomenon is discussed in terms of experimental data, results of Monte Carlo simulations, and theoretical models. Lattice version of DFT was developed for modeling phase transitions in adsorbed phase including wetting, capillary condensation, and ordering. Phase …
Date: January 5, 2006
Creator: Donohue, Marc
Object Type: Report
System: The UNT Digital Library
Development and Application of a Paleomagnetic/Geochemical Method for Constraining the Timing of Burial Diagenetic Events (open access)

Development and Application of a Paleomagnetic/Geochemical Method for Constraining the Timing of Burial Diagenetic Events

Studies of diagenesis caused by fluid migration or other events are commonly hindered by a lack of temporal control. Our results to date demonstrate that a paleomagnetic/geochemical approach can be used to date fluid migration as well as burial diagenetic events. Our principal working hypothesis is that burial diagenetic processes (e.g., maturation of organic-rich sediments and clay diagenesis) and the migration of fluids can trigger the authigenesis of magnetic mineral phases. The ages of these events can be constrained by comparing chemical remanent magnetizations (CRMs) to independently established Apparent Polar Wander Paths. Whilst geochemical (e.g. stable isotope and organic analyses) and petrographic studies provide important clues for establishing these relationships, the ultimate test of this hypothesis requires the application of independent dating methods to verify the paleomagnetic ages. Towards this end, we have used K-Ar dating of illitization as an alternative method for constraining the ages of magnetic mineral phases in our field areas. We have made significant progress toward understanding the origin and timing of chemical remagnetization related to burial diagenetic processes. For example, a recently completed field study documents a relationship between remagnetization and the maturation of organic matter (Blumstein et al., 2004). We have tested the hypothesized …
Date: January 5, 2006
Creator: Elmore, Richard D. & Engel, Michael H.
Object Type: Report
System: The UNT Digital Library
Gamma-ray Imaging Methods (open access)

Gamma-ray Imaging Methods

In this document we discuss specific implementations for gamma-ray imaging instruments including the principle of operation and describe systems which have been built and demonstrated as well as systems currently under development. There are several fundamentally different technologies each with specific operational requirements and performance trade offs. We provide an overview of the different gamma-ray imaging techniques and briefly discuss challenges and limitations associated with each modality (in the appendix we give detailed descriptions of specific implementations for many of these technologies). In Section 3 we summarize the performance and operational aspects in tabular form as an aid for comparing technologies and mapping technologies to potential applications.
Date: October 5, 2006
Creator: Vetter, K; Mihailescu, L; Nelson, K; Valentine, J & Wright, D
Object Type: Report
System: The UNT Digital Library
Attractor Explosions and Catalyzed Vacuum Decay (open access)

Attractor Explosions and Catalyzed Vacuum Decay

We present a mechanism for catalyzed vacuum bubble production obtained by combining moduli stabilization with a generalized attractor phenomenon in which moduli are sourced by compact objects. This leads straightforwardly to a class of examples in which the Hawking decay process for black holes unveils a bubble of a different vacuum from the ambient one, generalizing the new endpoint for Hawking evaporation discovered recently by Horowitz. Catalyzed vacuum bubble production can occur for both charged and uncharged bodies, including Schwarzschild black holes for which massive particles produced in the Hawking process can trigger vacuum decay. We briefly discuss applications of this process to the population and stability of metastable vacua.
Date: May 5, 2006
Creator: Green, Daniel; Silverstein, Eva & Starr, David
Object Type: Report
System: The UNT Digital Library
Dalitz Plot Analysis of the Decay B+ -> K+K+K- (open access)

Dalitz Plot Analysis of the Decay B+ -> K+K+K-

The authors perform an analysis of the three-body charmless decay B{sup {+-}} {yields} K{sup {+-}}K{sup {+-}}K{sup {-+}} using a sample of 226.0 {+-} 2.5 million B{bar B} pairs collected by the BABAR detector and measure the total branching fraction and Cp asymmetry to be {beta} = (35.2 {+-} 0.9 {+-} 1.6) x 10{sup -6} and A{sub CP} = (-1.7 {+-} 2.6 {+-} 1.5)%. They fit the Dalitz plot distribution using an isobar model and report the measured values of magnitudes and phases of the production coefficients. The decay dynamics is dominated by the K{sup +}K{sup -} S-wave, for which we perform a partial-wave analysis in the region m(K{sup +}K{sup -}) < 2 GeV/c{sup 2}. They find no evidence of CP violation for individual components of the isobar model.
Date: May 5, 2006
Creator: Dvoretskii, Alexei
Object Type: Report
System: The UNT Digital Library
Search for B Meson Decays to eta' eta' K (open access)

Search for B Meson Decays to eta' eta' K

The authors describe searches for decays of B mesons to the charmless final states {eta}'{eta}'K. The data consist of 228 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are {Beta}(B{sup 0} {yields} {eta}'{eta}'K{sup 0}) < 31 x 10{sup -6} and {Beta}(B{sup +} {yields} {eta}'{eta}'K{sup +}) < 25 x 10{sup -6}.
Date: May 5, 2006
Creator: Aubert, B.
Object Type: Report
System: The UNT Digital Library
Recent U.S. advances in ion-beam-driven high energy densityphysics and heavy ion fusion (open access)

Recent U.S. advances in ion-beam-driven high energy densityphysics and heavy ion fusion

During the past two years, significant experimental and theoretical progress has been made in the US heavy ion fusion science program in longitudinal beam compression, ion-beam-driven warm dense matter, beam acceleration, high brightness beam transport; and advanced theory and numerical simulations. Innovations in longitudinal compression of intense ion beams by > 50 X propagating through background plasma enable initial beam target experiments in warm dense matter to begin within the next two years. They are assessing how these new techniques might apply to heavy ion fusion drivers for inertial fusion energy.
Date: July 5, 2006
Creator: Logan, B. G.; Bieniosek, F. M.; Celata, C. M.; Coleman, J.; Greenway, W.; Henestroza, E. et al.
Object Type: Article
System: The UNT Digital Library
Magnetic Tools for Lab-on-a-chip Technologies (open access)

Magnetic Tools for Lab-on-a-chip Technologies

This study establishes a set of magnetics-based tools that have been integrated with microfluidic systems. The overall impact of the work begins to enable the rapid and efficient manipulation and detection of magnetic entities such as particles, picoliter-sized droplets, or bacterial cells. Details of design, fabrication, and theoretical and experimental assessments are presented. The manipulation strategy has been demonstrated in the format of a particle diverter, whereby micron-sized particles are actively directed into desired flow channels at a split-flow junction by means of integrated microelectromagnets. Magnetic detection has been realized by deploying Giant Magnetoresistance (GMR) sensors--microfabricated structures originally developed for use as readout elements in computer hard-drives. We successfully transferred the GMR technology to the lab-on-a-chip arena, and demonstrated the versatility of the concept in several important areas: real-time, integrated monitoring of the properties of multiphase droplet flows; rapid quantitative determination of the concentration of magnetic nanoparticles in droplets of ferrofluids; and high-speed detection of individual magnetic microparticles and magnetotactic bacteria. The study also includes novel schemes for hydrodynamic flow focusing that work in conjunction with GMR-based detection to ensure precise navigation of the sample stream through the GMR detection volume, therefore effectively establishing a novel concept of a microfabricated …
Date: August 5, 2006
Creator: Pekas, Nikola Slobodan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Optical Properties in Non-equilibrium Phase Transitions (open access)

Optical Properties in Non-equilibrium Phase Transitions

An open question about the dynamical behavior of materials is how phase transition occurs in highly non-equilibrium systems. One important class of study is the excitation of a solid by an ultrafast, intense laser. The preferential heating of electrons by the laser field gives rise to initial states dominated by hot electrons in a cold lattice. Using a femtosecond laser pump-probe approach, we have followed the temporal evolution of the optical properties of such a system. The results show interesting correlation to non-thermal melting and lattice disordering processes. They also reveal a liquid-plasma transition when the lattice energy density reaches a critical value.
Date: January 5, 2006
Creator: Ao, T; Ping, Y; Widmann, K; Price, D F; Lee, E; Tam, H et al.
Object Type: Article
System: The UNT Digital Library

Harnessing Innovation for a Renewable Energy Future

Keynote presentation given by Dan Arvizu at the Green Engineering Summit held in Anaheim, California on October 5, 2006.
Date: October 5, 2006
Creator: Arvizu, D.
Object Type: Presentation
System: The UNT Digital Library
Approaches to Beam Stabilization in X-Band Linear Colliders (open access)

Approaches to Beam Stabilization in X-Band Linear Colliders

In order to stabilize the beams at the interaction point, the X-band linear collider proposes to use a combination of techniques: inter-train and intra-train beam-beam feedback, passive vibration isolation, and active vibration stabilization based on either accelerometers or laser interferometers. These systems operate in a technologically redundant fashion: simulations indicate that if one technique proves unusable in the final machine, the others will still support adequate luminosity. Experiments underway for all of these technologies have already demonstrated adequate performance.
Date: September 5, 2006
Creator: Frisch, Josef; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Raubenheimer, Tor; Seryi, Andrei et al.
Object Type: Article
System: The UNT Digital Library
Gas Centrifuge Enrichment Plant Safeguards System Modeling (open access)

Gas Centrifuge Enrichment Plant Safeguards System Modeling

None
Date: July 5, 2006
Creator: Elayat, H A; O'Connell, W J & Boyer, B D
Object Type: Article
System: The UNT Digital Library
Observational Signatures and Non-Gaussianities ofGeneral Single Field Inflation (open access)

Observational Signatures and Non-Gaussianities ofGeneral Single Field Inflation

We perform a general study of primordial scalar non-Gaussianities in single field inflationary models. We consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first derivative, and the sound speed is arbitrary. We find that under reasonable assumptions, the non-Gaussianity is completely determined by 5 parameters. In special limits of the parameter space, one finds distinctive ''shapes'' of the non-Gaussianity. In models with a small sound speed, several of these shapes would become potentially observable in the near future. Different limits of our formulae recover various previously known results.
Date: May 5, 2006
Creator: Chen, Xingang; Huang, Min-xin; Kachru, Shamit & Shiu, Gary
Object Type: Report
System: The UNT Digital Library
Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV (open access)

Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV

Using 230.2 fb{sup -1} of e{sup +}e{sup -} annihilation data collected with the BABAR detector at and near the peak of the {Upsilon}(4S) resonance, 489 {+-} 55 events containing the pure leptonic decay D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}} have been isolated in charm-tagged events. The ratio of partial widths {Lambda}(D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}})/{Lambda}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) is measured to be 0.143 {+-} 0.018 {+-} 0.006 allowing a determination of the pseudoscalar decay constant f{sub D{sub 2}} = (283 {+-} 17 {+-} 7 {+-} 14) MeV. The errors are statistical, systematic, and from the D{sub s}{sup +} {yields} {phi}{pi}{sup +} branching ratio, respectively.
Date: September 5, 2006
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Measurements of |V_{cb}| and |V_{ub}| at BaBar (open access)

Measurements of |V_{cb}| and |V_{ub}| at BaBar

We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V{sub cb}| and |V{sub ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.
Date: January 5, 2006
Creator: Godang, Romulus & U., /Mississippi
Object Type: Article
System: The UNT Digital Library
Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystem Services Quarterly Report: January-March 2006 (open access)

Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystem Services Quarterly Report: January-March 2006

The overall purpose of this project is to evaluate the biological and economic feasibility of restoring high-quality forests on mined land, and to measure carbon sequestration and wood production benefits that would be achieved from forest restoration procedures. In this quarterly report we present data that show the spatial distribution of carbon in mine soils. Soil carbon data from deep soil pits from grassland minelands located in Ohio, Virginia, and West Virginia were analyzed to determine the vertical distribution and variability of soil organic carbon (SOC) down to a 2-m depth. Regression analyses were used to describe and model the distribution by soil depth of C(wt%), BD{sub fines}(g cm{sup -3}), and fines (vol%) in mine soils. The volume of excavated mine soil samples was transformed in terms of costs of digging and sampling, including sample collection and preparation, and C(wt%) analysis, in order to determine the maximum cost-effective depth (MCD) for carbon inventorying on the mined sites analyzed. Based on the horizontal variation of SOC(g m{sup -2}), we determined the sampling intensity required to achieve a desired accuracy of the amount of sequestered SOC(g m{sup -2}) at certain probability levels. The MCD and sampling intensity measurements were used to determine …
Date: May 5, 2006
Creator: Burger, James A.; Galbraith, J.; Fox, T.; Amacher, G.; Sullivan, J. & Zipper, C.
Object Type: Report
System: The UNT Digital Library
Dalitz Plot Analysis of $B^0_d \to K+ \pi^- \pi^0$ Decays (open access)

Dalitz Plot Analysis of $B^0_d \to K+ \pi^- \pi^0$ Decays

This thesis describes a Dalitz plot analysis of B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} decays. The data sample comprises 213 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center in California (SLAC). Preliminary results are presented for measurements of the inclusive branching fraction, quasi-two-body fractions and CP-violating charge asymmetries for intermediate states including K*(892){sup +}{pi}{sup -} and {rho}(770){sup -}K{sup +}. Observations of B{sup 0} decays to the K{pi} S-wave intermediate states, K*{sub 0}(1430){sup +}{pi}{sup -} and K*{sub 0}(1430){sup 0}{pi}{sup 0}, are reported. Evidence of the decay B{sup 0} {yields} K*(892){sup 0}{pi}{sup 0} is seen. We set upper limits at 90% confidence level on branching fractions of the nonresonant and other less significant intermediate states.
Date: May 5, 2006
Creator: Yu, Zhitang
Object Type: Report
System: The UNT Digital Library
TANK 50 BATCH 0 SALTSTONE FORMULATION CONFIRMATION (open access)

TANK 50 BATCH 0 SALTSTONE FORMULATION CONFIRMATION

Savannah River National Laboratory (SRNL) personnel were requested to confirm the Tank 50 Batch 0 grout formulation per Technical Task Request, SSF-TTR-2006-0001 (task 1 of 2) [1]. Earlier Batch 0 formulation testing used a Tank 50 sample collected in September 2005 and is described elsewhere [2]. The current testing was performed using a sample of Tank 50 waste collected in May 2006. This work was performed according to the Technical Task and Quality Assurance Plan (TT/QAP), WSRC-RP-2006-00594 [3]. The salt solution collected from Tank 50 in May 2006 contained approximately 3 weight percent more solids than the sample collected in September 2005. The insoluble solids took longer to settle in the new sample which was interpreted as indicating finer particles in the current sample. The saltstone formulation developed for the September 2005 Tank 50 Batch 0 sample was confirmed for the May 2006 sample with one minor exception. Saltstone prepared with the Tank 50 sample collected in May 2006 required 1.5 times more Daratard 17 set retarding admixture than the saltstone prepared with the September In addition, a sample prepared with lower shear mixing (stirring with a spatula) had a higher plastic viscosity (57 cP) than samples made with higher …
Date: June 5, 2006
Creator: Langton, C.
Object Type: Report
System: The UNT Digital Library
Potential Flammable Gas Explosion in the TRU Vent and Purge Machine (open access)

Potential Flammable Gas Explosion in the TRU Vent and Purge Machine

The objective of the analysis was to determine the failure of the Vent and Purge (V&P) Machine due to potential explosion in the Transuranic (TRU) drum during its venting and/or subsequent explosion in the V&P machine from the flammable gases (e.g., hydrogen and Volatile Organic Compounds [VOCs]) vented into the V&P machine from the TRU drum. The analysis considers: (a) increase in the pressure in the V&P cabinet from the original deflagration in the TRU drum including lid ejection, (b) pressure wave impact from TRU drum failure, and (c) secondary burns or deflagrations resulting from excess, unburned gases in the cabinet area. A variety of cases were considered that maximized the pressure produced in the V&P cabinet. Also, cases were analyzed that maximized the shock wave pressure in the cabinet from TRU drum failure. The calculations were performed for various initial drum pressures (e.g., 1.5 and 6 psig) for 55 gallon TRU drum. The calculated peak cabinet pressures ranged from 16 psig to 50 psig for various flammable gas compositions. The blast on top of cabinet and in outlet duct ranged from 50 psig to 63 psig and 12 psig to 16 psig, respectively, for various flammable gas compositions. The …
Date: April 5, 2006
Creator: Vincent, A
Object Type: Article
System: The UNT Digital Library
United States Energy Association Final Report International Partnership for the Hydrogen Economy Ministerial Conference (open access)

United States Energy Association Final Report International Partnership for the Hydrogen Economy Ministerial Conference

This report summarizes the activities of the United States Energy Association as it conducted the initial Ministerial Meeting of the International Partnership for the Hydrogen Economy in Washington, DC on November 18-21, 2003. The report summarizes the results of the meeting and subsequent support to the Office of Energy Efficiency and Renewable Energy in its role as IPHE Secretariat.
Date: April 5, 2006
Creator: Polen, William L.
Object Type: Report
System: The UNT Digital Library
Inhalation Exposure Input Parameters for the Biosphere Model (open access)

Inhalation Exposure Input Parameters for the Biosphere Model

This analysis is one of the technical reports that support the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), referred to in this report as the biosphere model. ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the conceptual model as well as the mathematical model and its input parameters. This report documents development of input parameters for the biosphere model that are related to atmospheric mass loading and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for a Yucca Mountain repository. ''Inhalation Exposure Input Parameters for the Biosphere Model'' is one of five reports that develop input parameters for the biosphere model. A graphical representation of the documentation hierarchy for the biosphere model is presented in Figure 1-1 (based on BSC 2006 [DIRS 176938]). This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and how this analysis report contributes to biosphere modeling. This analysis report defines and justifies values of atmospheric mass loading for the biosphere model. Mass loading is the total mass concentration of resuspended particles …
Date: June 5, 2006
Creator: Wasiolek, M.
Object Type: Report
System: The UNT Digital Library
Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$ (open access)

Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$

The present NLL prediction for the decay rate of the rare inclusive process {bar B} {yields} X{sub s}{gamma} has a large uncertainty due to the charm mass renormalization scheme ambiguity. We estimate that this uncertainty will be reduced by a factor of 2 at the NNLL level. This is a strong motivation for the on-going NNLL calculation, which will thus significantly increase the sensitivity of the observable {bar B} {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM. We also give a brief status report of the NNLL calculation.
Date: January 5, 2006
Creator: Asatrian, Hrachia M.; Hovhannisyan, Artyom; Poghosyan, Vahagn; Inst., /Yerevan Phys.; Greub, Christoph; U., /Bern et al.
Object Type: Article
System: The UNT Digital Library
An Investigation Into the Mechanics of Single Crystal Turbine Blades With a View Towards Enhancing Gas Turbine Efficiency (open access)

An Investigation Into the Mechanics of Single Crystal Turbine Blades With a View Towards Enhancing Gas Turbine Efficiency

The demand for increased efficiency of gas turbines used in power generation and aircraft applications has fueled research into advanced materials for gas turbine blades that can withstand higher temperatures in that they have excellent resistance to creep. The term ''Superalloys'' describes a group of alloys developed for applications that require high performance at elevated temperatures. Superalloys have a load bearing capacity up to 0.9 times their melting temperature. The objective of the investigation was to develop a thermodynamic model that can be used to describe the response of single crystal superalloys that takes into account the microstructure of the alloy within the context of a continuum model. Having developed the model, its efficacy was to be tested by corroborating the predictions of the model with available experimental data. Such a model was developed and it is implemented in the finite element software ABAQUS/STANDARD through a user subroutine (UMAT) so that the model can be used in realistic geometries that correspond to turbine blades.
Date: May 5, 2006
Creator: Rajagopal, K. R. & Rao, I. J.
Object Type: Report
System: The UNT Digital Library
Comparison of the LLNL ALE3D and AKTS Thermal Safety Computer Codes for Calculating Times to Explosion in ODTX and STEX Thermal Cookoff Experiments (open access)

Comparison of the LLNL ALE3D and AKTS Thermal Safety Computer Codes for Calculating Times to Explosion in ODTX and STEX Thermal Cookoff Experiments

Cross-comparison of the results of two computer codes for the same problem provides a mutual validation of their computational methods. This cross-validation exercise was performed for LLNL's ALE3D code and AKTS's Thermal Safety code, using the thermal ignition of HMX in two standard LLNL cookoff experiments: the One-Dimensional Time to Explosion (ODTX) test and the Scaled Thermal Explosion (STEX) test. The chemical kinetics model used in both codes was the extended Prout-Tompkins model, a relatively new addition to ALE3D. This model was applied using ALE3D's new pseudospecies feature. In addition, an advanced isoconversional kinetic approach was used in the AKTS code. The mathematical constants in the Prout-Tompkins code were calibrated using DSC data from hermetically sealed vessels and the LLNL optimization code Kinetics05. The isoconversional kinetic parameters were optimized using the AKTS Thermokinetics code. We found that the Prout-Tompkins model calculations agree fairly well between the two codes, and the isoconversional kinetic model gives very similar results as the Prout-Tompkins model. We also found that an autocatalytic approach in the beta-delta phase transition model does affect the times to explosion for some conditions, especially STEX-like simulations at ramp rates above 100 C/hr, and further exploration of that effect is warranted.
Date: April 5, 2006
Creator: Wemhoff, A P & Burnham, A K
Object Type: Report
System: The UNT Digital Library