Unification and extension of the similarity scaling criteria and mixing transition for studying astrophysics using high energy density laboratory experiments or numerial simulations (open access)

Unification and extension of the similarity scaling criteria and mixing transition for studying astrophysics using high energy density laboratory experiments or numerial simulations

The Euler similarity criteria for laboratory experiments and time-dependent mixing transition are important concepts introduced recently for application to prediction and analysis of astrophysical phenomena. However Euler scaling by itself provides no information on the distinctive spectral range of high Reynolds number turbulent flows found in astrophysics situations. On the other hand, time-dependent mixing transition gives no indication on whether a flow that just passed the mixing transition is sufficient to capture all of the significant dynamics of the complete astrophysical spectral range. In this paper, a new approach, based on additional insight gained from review of Navier-Stokes turbulence theory, is developed. It allows for revelations about the distinctive spectral scale dynamics associated with high Reynolds number astrophysical flows. From this perspective, we caution that the energy containing range of the turbulent flow measured in a laboratory setting must not be unintentionally contaminated in such a way that the interactive influences of this spectral scale range in the corresponding astrophysical situation cannot be faithfully represented. In this paper we introduce the concept of a minimum state as the lowest Reynolds number turbulent flow that a time-dependent mixing transition must achieve to fulfill this objective. Later in the paper we show …
Date: August 21, 2006
Creator: Zhou, Y
System: The UNT Digital Library
Partially redundant functions of two SET-domain polycomb-group proteins in controlling initiation of seed development in Arabidopsis (open access)

Partially redundant functions of two SET-domain polycomb-group proteins in controlling initiation of seed development in Arabidopsis

In Arabidopsis, a complex of Polycomb-group (PcG) proteins functions in the female gametophyte to control the initiation of seed development. Mutations in the PcG genes, including MEDEA (MEA) and FERTILIZATION-INDEPENDENT SEED 2 (FIS2), produce autonomous seeds where endosperm proliferation occurs in the absence of fertilization. By using a yeast two-hybrid screen, we identified MEA and a related protein, SWINGER (SWN), as SET-domain partners of FIS2. Localization data indicated that all three proteins are present in the female gametophyte. Although single-mutant swn plants did not show any defects, swn mutations enhanced the mea mutant phenotype in producing autonomous seeds. Thus, MEA and SWN perform partially redundant functions in controlling the initiation of endosperm development before fertilization in Arabidopsis.
Date: August 29, 2006
Creator: Wang, Dongfang; Tyson, Mark D.; Jackson, Shawn S. & Yadegari, Ramin
System: The UNT Digital Library
Efficient System Design and Sustainable Finance for China's Village Electrification Program: Preprint (open access)

Efficient System Design and Sustainable Finance for China's Village Electrification Program: Preprint

This paper describes a joint effort of the Institute for Electrical Engineering of the Chinese Academy of Sciences (IEE), and the U.S. National Renewable Energy Laboratory (NREL) to support China's rural electrification program. This project developed a design tool that provides guidelines both for off-grid renewable energy system designs and for cost-based tariff and finance schemes to support them. This tool was developed to capitalize on lessons learned from the Township Electrification Program that preceded the Village Electrification Program. We describe the methods used to develop the analysis, some indicative results, and the planned use of the tool in the Village Electrification Program.
Date: August 1, 2006
Creator: Ma, S.; Yin, H. & Kline, D. M.
System: The UNT Digital Library
Development of Nanofluidic Cells for Ultrafast X-ray Studies of Water (open access)

Development of Nanofluidic Cells for Ultrafast X-ray Studies of Water

In order to study the molecular structure and dynamics of liquid water with soft x-ray probes, samples with nanoscale dimensions are needed. This paper describes a simple method for preparing nanofluidic water cells. The idea is to confine a thin layer of water between two silicon nitride windows. The windows are 1 mm x 1 mm and 0.5 mm x 0.5 mm in size and have a thickness of 150 nm. The thickness of the water layer was measured experimentally by probing the infrared spectrum of water in the cells with a Fourier Transform InfraRed (FTIR) apparatus and from soft x-ray static measurements at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Water layers ranging from 10 nm to more than 2 {micro}m were observed. Evidence for changes in the water structure compared to bulk water is observed in the ultrathin cells.
Date: August 23, 2006
Creator: Irizarry, Melvin E. & /Puerto Rico U., Mayaguez /SLAC
System: The UNT Digital Library
A FAMILY OF PEROXO-TITANATE MATERIALS TAILORED FOR OPTIMAL STRONTIUM ANDACTINIDE SORPTION (open access)

A FAMILY OF PEROXO-TITANATE MATERIALS TAILORED FOR OPTIMAL STRONTIUM ANDACTINIDE SORPTION

Achieving global optimization of inorganic sorbent efficacy, as well as tailoring sorbent specificity for target sorbates would facilitate increased wide-spread use of these materials in applications such as producing potable water or nuclear waste treatment. Sodium titanates have long been known as sorbents for radionuclides; {sup 90}Sr and transuranic elements in particular. We have developed a related class of materials, which we refer to as peroxo-titanates: these are sodium titanates or hydrous titanates synthesized in the presence of or treated post-synthesis with hydrogen peroxide. Peroxo-titanates show remarkable and universal improved sorption behavior with respect to separation of actinides and strontium from Savannah River Site (SRS) nuclear waste simulants. Enhancement in sorption kinetics can potentially result in as much as an order of magnitude increase in batch processing throughput. Peroxo-titanates have been produced by three different synthetic routes: post-synthesis peroxide-treatment of a commercially produced monosodium titanate, an aqueous-peroxide synthetic route, and an isopropanol-peroxide synthetic route. The peroxo-titanate materials are characteristically yellow to orange, indicating the presence of protonated or hydrated Ti-peroxo species; and the chemical formula can be generally written as H{sub v}Na{sub w}Ti{sub 2}O{sub 5}-(xH{sub 2}O)[yH{sub z}O{sub 2}] where (v+w) = 2, z = 0-2, and total volatile species accounts …
Date: August 7, 2006
Creator: Hobbs, D
System: The UNT Digital Library
INTERIM STORAGE AND LONG TERM DISPOSAL OF RESEARCH REACTOR SPENT FUEL (open access)

INTERIM STORAGE AND LONG TERM DISPOSAL OF RESEARCH REACTOR SPENT FUEL

Aluminum clad research reactor spent nuclear fuel (SNF) is currently being consolidated in wet storage basins (pools). Approximately 20 metric tons (heavy metal) of aluminum-based spent nuclear fuel (Al-SNF) is being consolidated for treatment, packaging, interim storage, and preparation for ultimate disposal in a geologic repository. The storage and disposal of Al-SNF are subject to requirements that provide for safety and acceptable radionuclide release. The options studied for interim storage of SNF include wet storage and dry storage. Two options have also been studied to develop the technical basis for the qualification and repository disposal of aluminum spent fuel. The two options studied include Direct Disposal and Melt-Dilute treatment. The implementation of these options present relative benefits and challenges. Both the Direct Disposal and the Melt-Dilute treatment options have been developed and their technical viability assessed. Adaptation of the melt-dilute technology for the treatment of spent fuel offers the benefits of converting the spent fuel into a proliferation resistant form and/or significantly reducing the volume of the spent fuel. A Mobile Melt-Dilute system concept has emerged to realize these benefits and a prototype system developed. The application of the melt-dilute technology for the treatment of legacy nuclear materials has been …
Date: August 22, 2006
Creator: Vinson, D
System: The UNT Digital Library
Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider (open access)

Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider

Precise collimation of the beam halo is required in the International Linear Collider (ILC) to prevent beam losses near the interaction region that could cause unacceptable backgrounds for the physics detector. The necessarily small apertures of the collimators lead to transverse wakefields that may result in beam deflections and increased emittance. A set of collimator wakefield measurements has previously been performed in the ASSET region of the SLAC Linac. We report on the next phase of this program, which is carried out at the recently commissioned End Station A (ESA) test facility at SLAC. Measurements of resistive and geometric wakefields using tapered collimators are compared with model predictions from MAFIA and GdfidL and with analytic calculations.
Date: August 18, 2006
Creator: Watson, N. K.; Adeya, D.; Stockton, M. C.; Kolomensky, Y.; Slater, M.; Angal-Kalinin, D. et al.
System: The UNT Digital Library
Inclusive jet production at the Tevatron (open access)

Inclusive jet production at the Tevatron

Preliminary results on inclusive jet production in proton-antiproton collisions at {radical}s = 1.96 TeV based on 1 fb{sup -1} of CDF Run II data are presented. Measurements are preformed using different jet algorithms in a wide range of jet transverse momentum and jet rapidity. The measured cross sections are compared to next-to-leading order perturbative QCD calculations
Date: August 1, 2006
Creator: Norniella, Olga
System: The UNT Digital Library
NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE (open access)

NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE

NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron activation of the stable carrier. In some of the cases where no suitable stable carriers exist, the source has been used to generate radioactive tracers to yield separations.
Date: August 14, 2006
Creator: Diprete, D; C Diprete, C & Raymond Sigg, R
System: The UNT Digital Library
Effects of Material Improvement on CZT Detectors. (open access)

Effects of Material Improvement on CZT Detectors.

CZT material quality improvement has been achieved by optimizing the crystal growth process. N-type conductivity has been measured on as-grown, undoped, Cd{sub 0.9}Zn{sub 0.1}Te. Cd{sub 0.85}Zn{sub 0.15}Te crystals have been grown. for producing high resistivity CZT radiation detectors. The best FWHM of {sup 57}Co 122KeV spectrum was measured to be 3.7% and ({mu}{tau}){sub e} was 3 x 10{sup -3} cm{sup 2}V{sup -1}. The microscopic gamma ray response using a beam size of 10 {micro}m has been used to map the entire 4 mm x 4 mm detector. Several black spots indicating no signal responses were observed while all other areas showed an average of 65-70% collection efficiency. The black spots suggest that at those locations, the Te precipitates are larger than 10 {micro}m. Detailed microscopic infrared transmission measurement on the sample found that most Te precipitates have sizes of 4-6 {micro}m. Theoretical analysis of the results suggests that singly and doubly ionized Te{sub Cd}V{sub Cd}{sup 2} might be the shallow and deep donors previously assigned to Te{sub Cd} by us.
Date: August 13, 2006
Creator: Chu, M. & Carini, G.A.
System: The UNT Digital Library
Effect of Aggregation on Thermal Conduction in Colloidal Nanofluids (open access)

Effect of Aggregation on Thermal Conduction in Colloidal Nanofluids

Using effective medium theory we demonstrate that the thermal conductivity of nanofluids can be significantly enhanced by the aggregation of nanoparticles into clusters. The enhancement is based purely on conduction and does not require a novel mechanism. Predictions of the effective medium theory are in excellent agreement with detailed numerical calculations on model nanofluids involving fractal clusters and show the importance of cluster morphology on thermal conductivity enhancements.
Date: August 10, 2006
Creator: Prasher, R; Evans, W; Fish, J; Meakin, P; Phelan, P & Keblinski, Pawel
System: The UNT Digital Library
Cost Comparison of Linear and Circular Accelerators. (open access)

Cost Comparison of Linear and Circular Accelerators.

None
Date: August 6, 2006
Creator: Ruggiero, A.
System: The UNT Digital Library
Program Design Analysis using BEopt Building Energy Optimization Software: Defining a Technology Pathway Leading to New Homes with Zero Peak Cooling Demand; Preprint (open access)

Program Design Analysis using BEopt Building Energy Optimization Software: Defining a Technology Pathway Leading to New Homes with Zero Peak Cooling Demand; Preprint

An optimization method based on the evaluation of a broad range of different combinations of specific energy efficiency and renewable-energy options is used to determine the least-cost pathway to the development of new homes with zero peak cooling demand. The optimization approach conducts a sequential search of a large number of possible option combinations and uses the most cost-effective alternatives to generate a least-cost curve to achieve home-performance levels ranging from a Title 24-compliant home to a home that uses zero net source energy on an annual basis. By evaluating peak cooling load reductions on the least-cost curve, it is then possible to determine the most cost-effective combination of energy efficiency and renewable-energy options that both maximize annual energy savings and minimize peak-cooling demand.
Date: August 1, 2006
Creator: Anderson, R.; Christensen, C. & Horowitz, S.
System: The UNT Digital Library
The First Lasing of 193 Nm Sase, 4th Harmonic Hghg and Esase at the Nsls Sdl. (open access)

The First Lasing of 193 Nm Sase, 4th Harmonic Hghg and Esase at the Nsls Sdl.

The first lasing of three types of single-pass high-gain FELs, SASE at 193 nm, 4th harmonic HGHG at 199 nm and ESASE at the Source Development Lab (SDL) of Brookhaven National Laboratory (BNL) is reported. The saturation of 4th harmonic HGHG and ESASE FELs was observed. We also observed the spectral broadening and instability of the 4th harmonic HGHG.
Date: August 28, 2006
Creator: Wang, X. J.; Shen, Y.; Watanabe, T.; Murphy, J. B.; Rose, J. & Tsang, T.
System: The UNT Digital Library
The Radiation Dose Measurement System for the BaBar Electromagnetic Calorimeter (open access)

The Radiation Dose Measurement System for the BaBar Electromagnetic Calorimeter

An array of 116 p-channel radiation sensitive MOSFET transistors (RadFETs) has been operational for the past 6 years at the BaBar experiment at the PEP-II asymmetric B-Factory at the Stanford Linear Accelerator Center (SLAC). This system maps the integrated dose absorbed by different regions of the Electromagnetic Calorimeter (EMC) during the running of the experiment. We report on the design and implementation of the system and finally, the performance of the monitoring system during the last 6 years of BaBar data-taking.
Date: August 14, 2006
Creator: Khan, A.; U., /Brunel; Meyer, W.T.; U., /Iowa State; Stelzer, J.; /Stanford U., Phys. Dept. et al.
System: The UNT Digital Library
Measurement of the B+ ->eta l+ nu and B+ -> eta' l+ nu Branching Fractions using Upsilon(4S) -> B Bbar Events Tagged by a Fully Reconstructed B Meson (open access)

Measurement of the B+ ->eta l+ nu and B+ -> eta' l+ nu Branching Fractions using Upsilon(4S) -> B Bbar Events Tagged by a Fully Reconstructed B Meson

We report preliminary measurements of the exclusive charmless semileptonic branching fractions of the B{sup +} {yields} {eta}{ell}{sup +}{nu} and B{sup +} {yields} {eta}'{ell}{sup +}{nu} decays. These measurements are based on 316 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the BABAR detector. In events in which the decay of one B meson to a hadronic final state is fully reconstructed, the semileptonic decay of the recoiling B meson is identified by the detection of a charged lepton and an {eta} or {eta}'. We measure the branching fraction {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) = (0.84 {+-} 0.27 {+-} 0.21) x 10{sup -4}, where the first error is statistical and the second one systematic. We also set an upper limit on the branching fraction of {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) < 1.4 x 10{sup -4} and {Beta}(B{sup +} {yields} {eta}'{ell}{sup +}{nu}) < 1.3 x 10{sup -4} at the 90% confidence level.
Date: August 18, 2006
Creator: D'Orazio, A
System: The UNT Digital Library
A Measurement of CP-violation Parameters in B0B0barMixing using Partially Reconstructed D^{*-}l^+ nu_l Events at BaBar (open access)

A Measurement of CP-violation Parameters in B0B0barMixing using Partially Reconstructed D^{*-}l^+ nu_l Events at BaBar

CP violation in B{sup 0}{bar B}{sup 0} mixing is characterized by the value of the parameter |q/p| being different from 1, and the Standard Model predicts this difference to be smaller than 10{sup -3}. We present a measurement of this parameter using a partial reconstruction of one of the B mesons in the semileptonic channel D*{sup -}{ell}{sup +}{nu}{sub {ell}}, where only the hard lepton and the soft pion from the D*{sup -} {yields} {bar D}{sup 0}{pi}{sup -} decay are reconstructed. The flavor of the other B is determined by means of lepton tagging. The determination of |q/p| is then performed with a fit to the proper time difference of the two B decays. We use a luminosity of 200.8 fb{sup -1}, collected at the {Upsilon}(4S) resonance by the BABAR detector at the PEP-II asymmetrical-energy e{sup +}e{sup -} collider, in the period 1999-2004. We obtain the preliminary result: |q/p| - 1 = (6.5 {+-} 3.4(stat.) {+-} 2.0(syst.)) {center_dot} 10{sup -3}.
Date: August 18, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Multi-Year Analysis of Renewable Energy Impacts in California: Results from the Renewable Portfolio Standards Integration Cost Analysis; Preprint (open access)

Multi-Year Analysis of Renewable Energy Impacts in California: Results from the Renewable Portfolio Standards Integration Cost Analysis; Preprint

California's Renewable Portfolio Standard (RPS, Senate Bill 1078) requires the state's investor-owned utilities to obtain 20% of their energy mix from renewable generation sources. To facilitate the imminent increase in the penetration of renewables, the California Energy Commission (CEC), in support of the California Public Utility Commission (CPUC), initiated a study of integration costs in the context of RPS implementation. This effort estimated the impact of renewable generation in the regulation and load-following time scales and calculated the capacity value of renewable energy sources using a reliability model. The analysis team, consisting of researchers from the National Renewable Energy Laboratory (NREL), Oak Ridge National Laboratory (ORNL) and the California Wind Energy Collaborative (CWEC), performed the study in cooperation with the California Independent System Operator (CaISO), the Pacific Gas and Electric Company (PG&E), and Southern California Edison (SCE). The study was conducted over three phases and was followed by an analysis of a multi-year period. This paper presents results from the multi-year analysis and the Phase III recommendations.
Date: August 1, 2006
Creator: Milligan, M.; Shiu, H.; Kirby, B. & Jackson, K.
System: The UNT Digital Library
Blind Analysis in Nuclear and Particle Physics (open access)

Blind Analysis in Nuclear and Particle Physics

None
Date: August 11, 2006
Creator: Klein, J.R.; U., /Texas & Roodman, A.
System: The UNT Digital Library
UPTAKE OF RADIONUCLIDE METALS BY SPME FIBERS (open access)

UPTAKE OF RADIONUCLIDE METALS BY SPME FIBERS

The Federal Bureau of Investigation (FBI) Laboratory currently does not have on site facilities for handling radioactive evidentiary materials and there are no established FBI methods or procedures for decontaminating high explosive (HE) and fire debris (FD) evidence while maintaining evidentiary value. One experimental method for the isolation of HE and FD residue involves using solid phase microextraction or SPME fibers to remove residue of interest. Due to their high affinity for organics, SPME fibers should have little affinity for most metals. However, no studies have measured the affinity of radionuclides for SPME fibers. The focus of this research was to examine the affinity of dissolved radionuclide ({sup 239/240}Pu, {sup 238}U, {sup 237}Np, {sup 85}Sr, {sup 133}Ba, {sup 137}Cs, {sup 60}Co and {sup 226}Ra) and stable radionuclide surrogate metals (Sr, Co, Ir, Re, Ni, Ba, Cs, Nb, Zr, Ru, and Nd) for SPME fibers at the exposure conditions that favor the uptake of HE and FD residues. Our results from radiochemical and mass spectrometric analyses indicate these metals have little measurable affinity for these SPME fibers during conditions that are conducive to HE and FD residue uptake with subsequent analysis by liquid or gas phase chromatography with mass spectrometric detection.
Date: August 28, 2006
Creator: Duff, M; S Crump, S; Robert02 Ray, R; Keisha Martin, K & Donna Beals, D
System: The UNT Digital Library
DEUTERIUM, TRITIUM, AND HELIUM DESORPTION FROM AGED TITANIUM TRITIDES. PART II. (open access)

DEUTERIUM, TRITIUM, AND HELIUM DESORPTION FROM AGED TITANIUM TRITIDES. PART II.

Six new samples of tritium-aged bulk titanium have been examined by thermal desorption and isotope exchange chemistry. The discovery of a lower temperature hydrogen desorption state in these materials, previously reported, has been confirmed in one of the new samples. The helium release of the samples shows the more severe effects obtained from longer aging periods, i.e. higher initial He/M ratios. Several of the more aged samples were spontaneously releasing helium. Part I discussed the new results on the new lower temperature hydrogen desorption state found in one more extensively studied sample. Part II will discuss the hydrogen/helium release behavior of the remaining samples.
Date: August 17, 2006
Creator: Shanahan, K & Jeffrey Holder, J
System: The UNT Digital Library
Whole-House Energy Analysis Procedures for Existing Homes: Preprint (open access)

Whole-House Energy Analysis Procedures for Existing Homes: Preprint

This paper describes a proposed set of guidelines for analyzing the energy savings achieved by a package of retrofits or an extensive rehabilitation of an existing home. It also describes certain field test and audit methods that can help establish accurate building system performance characteristics that are needed for a meaningful simulation of whole-house energy use. Several sets of default efficiency values have been developed for older appliances that cannot be easily tested and for which published specifications are not readily available. These proposed analysis procedures are documented more comprehensively in NREL Technical Report TP-550-38238.
Date: August 1, 2006
Creator: Hendron, R.
System: The UNT Digital Library
Comparison Between H-Ion and Heat Cleaning of Cu-Metal Cathodes (open access)

Comparison Between H-Ion and Heat Cleaning of Cu-Metal Cathodes

Understanding the quantum efficiency (QE) of a metal photocathode in an s-band RF gun is important to limit the drive laser energy requirement and provide the best quality electron beam. Systematic measurements of the qe vs. wavelength for varying surface contamination have been performed on copper samples using x-ray photoelectron spectroscopy (XPS). The sample is first cleaned to the theoretical limit of QE using a 1 keV hydrogen ion beam. The H-ion beam cleans an area approximately 1cm in diameter and has no effect on the surface roughness while removing essentially all contaminants and lowering the work function to 4.3eV[1]. The sample is then exposed to atmospheric contaminants (nitrogen and oxygen) and measured again with XPS to determine the degree of contamination and their effect on the QE. These results and comparison with theory are presented.
Date: August 18, 2006
Creator: Dowell, D. H.; King, F. K.; Kirby, R. E. & Schmerge, J. F.
System: The UNT Digital Library
An Integrated Front-End Readout And Feature Extraction System for the BaBar Drift Chamber (open access)

An Integrated Front-End Readout And Feature Extraction System for the BaBar Drift Chamber

The BABAR experiment has been operating at SLAC's PEP-II asymmetric B-Factory since 1999. The accelerator has achieved more than three times its original design luminosity of 3 x 10{sup 33} cm{sup -2} s{sup -1}, with plans for an additional factor of three in the next two years. To meet the experiment's performance requirements in the face of significantly higher trigger and background rates, the drift chamber's front-end readout system has been redesigned around the Xilinx Spartan 3 FPGA. The new system implements analysis and feature-extraction of digitized waveforms in the front-end, reducing the data bandwidth required by a factor of four.
Date: August 10, 2006
Creator: Zhang, Jinlong
System: The UNT Digital Library