Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells (open access)

Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells

Spin Hall effect can be induced both by the extrinsic impurity scattering and by the intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. This difference gives a direct mechanism to experimentally distinguish the intrinsic spin Hall effect from the extrinsic one.
Date: March 19, 2010
Creator: Yang, Wen; Chang, Kai & Zhang, Shou-Cheng
Object Type: Article
System: The UNT Digital Library
Jitter Studies for a 2.4 GeV Light Source Accelerator Using LiTrack (open access)

Jitter Studies for a 2.4 GeV Light Source Accelerator Using LiTrack

Electron beam quality is an important factor in the performance of a free electron laser (FEL). Parameters of particular interest are the electron beam energy, slice emittance and energy spread, peak current, and energy chirp. Jitter in average energy is typically many times the slice energy spread. A seeded FEL is sensitive not only to these local properties but also to factors such as shot-to-shot consistency and the uniformity of the energy and current profiles across the bunch. The timing and bunch length jitter should be controlled to maximize the interval of time over which the electron beam can be reliably seeded by a laser to produce good output in the FEL. LiTrack, a one-dimensional tracking code which includes the effect of longitudinal wakefields, is used to study the sensitivity of the accelerator portion of a 2.4 GeV FEL to sources of variability such as the radio frequency (RF) cavities, chicanes, and the timing and efficiency of electron production at the photocathode. The main contributors to jitter in the resulting electron beam are identified and quantified for various figures of merit.
Date: March 19, 2010
Creator: Penn, Gregory E
Object Type: Report
System: The UNT Digital Library
The Lanczos Method Applied to Statistical Stark Broadening of Spectral Lines (open access)

The Lanczos Method Applied to Statistical Stark Broadening of Spectral Lines

None
Date: February 19, 2010
Creator: Sonnad, V & Iglesias, C A
Object Type: Article
System: The UNT Digital Library
Lessons from Two Years of Building Fusion Ignition Targets with the Precision Robotic Assembly Machine (open access)

Lessons from Two Years of Building Fusion Ignition Targets with the Precision Robotic Assembly Machine

The Precision Robotic Assembly Machine was developed to manufacture the small and intricate laser-driven fusion ignition targets that are being used in the world's largest and most energetic laser, the National Ignition Facility (NIF). The National Ignition Campaign (NIC) goal of using the NIF to produce a self-sustaining nuclear fusion burn with energy gain - for the first time ever in a laboratory setting - requires targets that are demanding in materials fabrication, machining, and assembly. We provide an overview of the design and function of the machine, with emphasis on the aspects that revolutionized how NIC targets are manufactured.
Date: February 19, 2010
Creator: Montesanti, R C; Alger, E T; Atherton, L J; Bhandarkar, S D; Castro, C; Dzenitis, E G et al.
Object Type: Article
System: The UNT Digital Library
Low Dose Radiation-Induced Genome and Epigenome Instability Symposium and Epigenetic Mechanisms, DNA Repair, and Chromatin Symposium at the EMS 2008 Annual Meeting - October 2008 (open access)

Low Dose Radiation-Induced Genome and Epigenome Instability Symposium and Epigenetic Mechanisms, DNA Repair, and Chromatin Symposium at the EMS 2008 Annual Meeting - October 2008

The Low Dose Radiation Symposium thoughtfully addressed ionizing radiation non-mutational but transmissable alterations in surviving cells. Deregulation of epigenetic processes has been strongly implicated in carcinogenesis, and there is increasing realization that a significant fraction of non-targeted and adaptive mechanisms in response to ionizing radiation are likely to be epigenetic in nature. Much remains to be learned about how chromatin and epigenetic regulators affect responses to low doses of radiation, and how low dose radiation impacts other epigenetic processes. The Epigenetic Mechanisms Symposium focused on on epigenetic mechanisms and their interplay with DNA repair and chromatin changes. Addressing the fact that the most well understood mediators of epigenetic regulation are histone modifications and DNA methylation. Low levels of radiation can lead to changes in the methylation status of certain gene promoters and the expression of DNA methyltransferases, However, epigenetic regulation can also involve changes in higher order chromosome structure.
Date: February 19, 2010
Creator: Morgan, William F.; Kovalchuk, Olga; Dolinoy, Dana C.; Dubrova, Yuri E.; Coleman, Matthew A.; Schär, Primo et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the 208Pb(52Cr, n)259Sg Excitation Function (open access)

Measurement of the 208Pb(52Cr, n)259Sg Excitation Function

The excitation function for the 208Pb(52Cr, n)259Sg reaction has been measured using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. The maximum cross section of pb is observed at a center-of-target laboratory-frame energy of 253.0 MeV. In total, 25 decay chains originating from 259Sg were observed and the measured decay properties are in good agreement with previous reports. In addition, a partial excitation function for the 208Pb(52Cr, 2n)258Sg reaction was obtained, and an improved 258Sg half-life of ms was calculated by combining all available experimental data.
Date: March 19, 2010
Creator: Folden, C. M., III; Dragojevic, I.; Dullmann, Ch. E.; Eichler, R.; Garcia, M. A.; Gates, J. M. et al.
Object Type: Article
System: The UNT Digital Library
Measurements of the Ion Species of Cathodic Arc Plasma in an Axial Magnetic Field (open access)

Measurements of the Ion Species of Cathodic Arc Plasma in an Axial Magnetic Field

Metal and gas ion species and their charge state distributions were measured for pulsed copper cathodic arcs in argon background gas in the presence of an axial magnetic field. It was found that changing the cathode position relative to anode and ion extraction system as well as increasing the gas pressure did not much affect the arc burning voltage and the related power dissipation. However, the burning voltage and power dissipation greatly increased as the magnetic field strength was increased. The fraction of metal ions and the mean ion charge state were reduced as the discharge length was increased. The observations can be explained by the combination of charge exchange collisions and electron impact ionization. They confirm that previously published data on characteristic material-dependent charge state distributions (e.g., Anders and Yushkov, J. Appl. Phys., Vol. 91, pp. 4824-4832, 2002) are not universal but valid for high vacuum conditions and the specifics of the applied magnetic fields.
Date: October 19, 2010
Creator: Oks, Efim & Anders, Andre
Object Type: Article
System: The UNT Digital Library
Microtomography and pore-scale modeling of two-phase Fluid Distribution (open access)

Microtomography and pore-scale modeling of two-phase Fluid Distribution

Synchrotron-based X-ray microtomography (micro CT) at the Advanced Light Source (ALS) line 8.3.2 at the Lawrence Berkeley National Laboratory produces three-dimensional micron-scale-resolution digital images of the pore space of the reservoir rock along with the spacial distribution of the fluids. Pore-scale visualization of carbon dioxide flooding experiments performed at a reservoir pressure demonstrates that the injected gas fills some pores and pore clusters, and entirely bypasses the others. Using 3D digital images of the pore space as input data, the method of maximal inscribed spheres (MIS) predicts two-phase fluid distribution in capillary equilibrium. Verification against the tomography images shows a good agreement between the computed fluid distribution in the pores and the experimental data. The model-predicted capillary pressure curves and tomography-based porosimetry distributions compared favorably with the mercury injection data. Thus, micro CT in combination with modeling based on the MIS is a viable approach to study the pore-scale mechanisms of CO{sub 2} injection into an aquifer, as well as more general multi-phase flows.
Date: October 19, 2010
Creator: Silin, D.; Tomutsa, L.; Benson, S. & Patzek, T.
Object Type: Article
System: The UNT Digital Library
Multiscale analysis of nonlinear systems using computational homology (open access)

Multiscale analysis of nonlinear systems using computational homology

This is a collaborative project between the principal investigators. However, as is to be expected, different PIs have greater focus on different aspects of the project. This report lists these major directions of research which were pursued during the funding period: (1) Computational Homology in Fluids - For the computational homology effort in thermal convection, the focus of the work during the first two years of the funding period included: (1) A clear demonstration that homology can sensitively detect the presence or absence of an important flow symmetry, (2) An investigation of homology as a probe for flow dynamics, and (3) The construction of a new convection apparatus for probing the effects of large-aspect-ratio. (2) Computational Homology in Cardiac Dynamics - We have initiated an effort to test the use of homology in characterizing data from both laboratory experiments and numerical simulations of arrhythmia in the heart. Recently, the use of high speed, high sensitivity digital imaging in conjunction with voltage sensitive fluorescent dyes has enabled researchers to visualize electrical activity on the surface of cardiac tissue, both in vitro and in vivo. (3) Magnetohydrodynamics - A new research direction is to use computational homology to analyze results of large …
Date: May 19, 2010
Creator: Mischaikow, Konstantin; Schatz, Michael; Kalies, William & Wanner, Thomas
Object Type: Report
System: The UNT Digital Library
Nevada Test Site 2009 Data Report: Groundwater Monitoring Program, Area 5 Radioactive Waste Management Site (open access)

Nevada Test Site 2009 Data Report: Groundwater Monitoring Program, Area 5 Radioactive Waste Management Site

This report is a compilation of the groundwater sampling results from the Area 5 Radioactive Waste Management Site (RWMS). The data have been collected since 1993 and include calendar year 2009 results. During 2009, groundwater at each of the three pilot wells was sampled on March 10, 2009, and August 18, 2009, and water levels at each of the three pilot wells were measured on February 17, May 6, August 17, and November 10, 2009. Groundwater samples were analyzed for the following indicators of contamination: pH, specific conductance, total organic carbon, total organic halides, and tritium. Indicators of general water chemistry (cations and anions) were also measured. Results from all samples collected in 2009 were within the limits established by agreement with the Nevada Division of Environmental Protection for each analyte. These data indicate that there has been no measurable impact to the uppermost aquifer from the Area 5 RWMS. There were no significant changes in measured groundwater parameters compared to previous years. The report contains an updated cumulative chronology for the Area 5 RWMS Groundwater Monitoring Program and a brief description of the site hydrogeology.
Date: January 19, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
NEXT GENERATION MELTER OPTIONEERING STUDY - INTERIM REPORT (open access)

NEXT GENERATION MELTER OPTIONEERING STUDY - INTERIM REPORT

The next generation melter (NOM) development program includes a down selection process to aid in determining the recommended vitrification technology to implement into the WTP at the first melter change-out which is scheduled for 2025. This optioneering study presents a structured value engineering process to establish and assess evaluation criteria that will be incorporated into the down selection process. This process establishes an evaluation framework that will be used progressively throughout the NGM program, and as such this interim report will be updated on a regular basis. The workshop objectives were achieved. In particular: (1) Consensus was reached with stakeholders and technology providers represented at the workshop regarding the need for a decision making process and the application of the D{sub 2}0 process to NGM option evaluation. (2) A framework was established for applying the decision making process to technology development and evaluation between 2010 and 2013. (3) The criteria for the initial evaluation in 2011 were refined and agreed with stakeholders and technology providers. (4) The technology providers have the guidance required to produce data/information to support the next phase of the evaluation process. In some cases it may be necessary to reflect the data/information requirements and overall approach …
Date: October 19, 2010
Creator: MF, GRAY; RB, CALMUS; G, RAMSEY; J, LOMAX & H, ALLEN
Object Type: Report
System: The UNT Digital Library
Origin of the Delayed Current Onset in High Power Impulse Magnetron Sputtering (open access)

Origin of the Delayed Current Onset in High Power Impulse Magnetron Sputtering

Repetitive pulses of voltage and current are applied in high power impulse magnetron sputtering. The current pulse usually lags the applied voltage by a significant time, which in some cases can reach many 10s of microseconds. The current time lag is generally highly reproducible and jitters less than 1percent of the delay time. This work investigates the time lag experimentally and theoretically. The experiments include several different target and gas combinations, voltage and current amplitudes, gas pressures, pulse repetition rates, and pulse durations. It is shown that in all cases the inverse delay is approximately proportional to the applied voltage, where the proportionality factor depends on the combination of materials and the conditions selected. The proportionality factor contains the parameters of ionization and secondary electron emission. The statistical time lag is negligible while the formative time lag is large and usually dominated by the ion motion (inertia), although, at low pressure, the long free path of magnetized electrons causing ionization contributes to the delay.
Date: July 19, 2010
Creator: Yushkov, Georgy Yu. & Anders, Andre
Object Type: Article
System: The UNT Digital Library
Parametric System Curves: Correlations Between Fan Pressure Rise and Flow for Large Commercial Buildings (open access)

Parametric System Curves: Correlations Between Fan Pressure Rise and Flow for Large Commercial Buildings

A substantial fraction of HVAC energy use in large commercial buildings is due to fan operation. Fan energy use depends in part on the relationship between system pressure drop and flow through the fan, which is commonly called a "system curve." As a step toward enabling better selections of air-handling system components and analyses of common energy efficiency measures such as duct static pressure reset and duct leakage sealing, this paper shows that a simple four-parameter physical model can be used to define system curves. Our model depends on the square of the fan flow, as is commonly considered. It also includes terms that account for linear-like flow resistances such as filters and coils, and for supply duct leakage when damper positions are fixed or are changed independently of static pressure or fan flow. Only two parameters are needed for systems with variable-position supply dampers (e.g., VAV box dampers modulating to control flow). For these systems, reducing or eliminating supply duct leakage does not change the system curve. The parametric system curve may be most useful when applied to field data. Non-linear techniques could be used to fit the curve to fan pressure rise and flow measurements over a range …
Date: May 19, 2010
Creator: Sherman, Max & Wray, Craig
Object Type: Report
System: The UNT Digital Library
THE POSITIVE IMPACTS OF AMERICAN REINVESTMENT AND RECOVERY ACT (ARRA) FUNDING TO THE WASTE MANAGEMENT PROGRAM ON HANFORD'S PLATEAU REMEDIATION PROJECT (open access)

THE POSITIVE IMPACTS OF AMERICAN REINVESTMENT AND RECOVERY ACT (ARRA) FUNDING TO THE WASTE MANAGEMENT PROGRAM ON HANFORD'S PLATEAU REMEDIATION PROJECT

In April 2009, the Department of Energy (DOE) Richland Operations Office (RL) was allocated $1.6 billion (B) in ARRA funding to be applied to cleanup projects at the Hanford Site. DOE-RL selected projects to receive ARRA funding based on 3-criteria: creating/saving jobs, reducing the footprint of the Hanford Site, and reducing life-cycle costs for cleanup. They further selected projects that were currently covered under regulatory documents and existing prime contracts, which allowed work to proceed quickly. CH2M HILL Plateau Remediation Company (CHPRC) is a prime contractor to the DOE focused on the environmental cleanup of the DOE Hanford Site Central Plateau. CHPRC was slated to receive $1.36B in ARRA funding. As of January, 2010, CHPRC has awarded over $200 million (M) in subcontracts (64% to small businesses), created more that 1,100 jobs, and touched more than 2,300 lives - all in support of long-term objectives for remediation of the Central Plateau, on or ahead of schedule. ARRA funding is being used to accelerate and augment cleanup activities already underway under the baseline Plateau Remediation Contract (PRC). This paper details challenges and accomplishments using ARRA funding to meet DOE-RL objectives of creating/saving jobs, expediting cleanup, and reducing lifecycle costs for cleanup …
Date: January 19, 2010
Creator: LT, BLACKFORD
Object Type: Article
System: The UNT Digital Library
Proceedings of Pulsed Magnet Design and Measurement Workshop (open access)

Proceedings of Pulsed Magnet Design and Measurement Workshop

The goals of the Workshop are to assess the design of pulsed system at the NSLS-II and establish mitigation strategies for critical issues during development. The focus of the Workshop is on resolving questions related to the set-up of the pulsed magnet laboratory, on measuring the pulsed magnet's current waveforms and fields, and on achieving tight tolerances on the magnet's alignment and field quality.
Date: January 19, 2010
Creator: Shaftan, T.; Heese, R. & Ozaki,S.
Object Type: Report
System: The UNT Digital Library
Progress in Understanding Error-field Physics in NSTX Spherical Torus Plasmas (open access)

Progress in Understanding Error-field Physics in NSTX Spherical Torus Plasmas

The low aspect ratio, low magnetic field, and wide range of plasma beta of NSTX plasmas provide new insight into the origins and effects of magnetic field errors. An extensive array of magnetic sensors has been used to analyze error fields, to measure error field amplification, and to detect resistive wall modes in real time. The measured normalized error-field threshold for the onset of locked modes shows a linear scaling with plasma density, a weak to inverse dependence on toroidal field, and a positive scaling with magnetic shear. These results extrapolate to a favorable error field threshold for ITER. For these low-beta locked-mode plasmas, perturbed equilibrium calculations find that the plasma response must be included to explain the empirically determined optimal correction of NSTX error fields. In high-beta NSTX plasmas exceeding the n=1 no-wall stability limit where the RWM is stabilized by plasma rotation, active suppression of n=1 amplified error fields and the correction of recently discovered intrinsic n=3 error fields have led to sustained high rotation and record durations free of low-frequency core MHD activity. For sustained rotational stabilization of the n=1 RWM, both the rotation threshold and magnitude of the amplification are important. At fixed normalized dissipation, kinetic …
Date: May 19, 2010
Creator: E. Menard, R.E. Bell, D.A. Gates, S.P. Gerhardt, J.-K. Park, S.A. Sabbagh, J.W. Berkery, A. Egan, J. Kallman, S.M. Kaye, B. LeBlanc, Y.Q. Liu, A. Sontag, D. Swanson, H. Yuh, W. Zhu and the NSTX Research Team
Object Type: Report
System: The UNT Digital Library
Progress with Tevatron Electron Lens Head-On Beam-Beam Compensation (open access)

Progress with Tevatron Electron Lens Head-On Beam-Beam Compensation

Tevatron electron lenses have been successfully used to mitigate bunch-to-bunch differences caused by longrange beam-beam interactions. For this purpose, the electron beam with uniform transverse density distribution was used. Another planned application of the electron lens is the suppression of tune spread due to head-on beam-beam collisions. For this purpose, the transverse distribution of the E{sup -} beam must be matched to that of the antiproton beam. In 2009, the Gaussian profile electron gun was installed in one of the Tevatron electron lenses. We report on the first experiments with non-linear beam-beam compensation. Discussed topics include measurement and control of the betatron tune spread, importance of the beam alignment and stability, and effect of electron lens on the antiproton beam lifetime.
Date: May 19, 2010
Creator: Valishev, A.; Kuznetsov, G.; Shiltsev, V.; Stancari, G. & Zhang, X.
Object Type: Article
System: The UNT Digital Library
Quantification of thin film crystallographic orientation using X-ray diffraction with an area detector (open access)

Quantification of thin film crystallographic orientation using X-ray diffraction with an area detector

As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological information is needed to predict and optimize the film's electronic, optical and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector and synchrotron radiation in two simple geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly-packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.
Date: February 19, 2010
Creator: Baker, Jessica L; Jimison, Leslie H; Mannsfeld, Stefan; Volkman, Steven; Yin, Shong; Subramanian, Vivek et al.
Object Type: Article
System: The UNT Digital Library
Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells (open access)

Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells

The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
Date: March 19, 2010
Creator: Liu, Chao-Xing; Qi, Xiao-Liang; Dai, Xi; Fang, Zhong & Zhang, Shou-Cheng
Object Type: Article
System: The UNT Digital Library
Radiation in Particle Simulations (open access)

Radiation in Particle Simulations

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third …
Date: November 19, 2010
Creator: More, R; Graziani, F; Glosli, J & Surh, M
Object Type: Article
System: The UNT Digital Library
RCRA Part A and Part B Permit Application for Waste Management Activities at the Nevada Test Site: Proposed Mixed Waste Disposal Unit (MWSU) (open access)

RCRA Part A and Part B Permit Application for Waste Management Activities at the Nevada Test Site: Proposed Mixed Waste Disposal Unit (MWSU)

The proposed Mixed Waste Storage Unit (MWSU) will be located within the Area 5 Radioactive Waste Management Complex (RWMC). Existing facilities at the RWMC will be used to store low-level mixed waste (LLMW). Storage is required to accommodate offsite-generated LLMW shipped to the Nevada Test Site (NTS) for disposal in the new Mixed Waste Disposal Unit (MWDU) currently in the design/build stage. LLMW generated at the NTS (onsite) is currently stored on the Transuranic (TRU) Pad (TP) in Area 5 under a Mutual Consent Agreement (MCA) with the Nevada Division of Environmental Protection, Bureau of Federal Facilities (NDEP/BFF). When the proposed MWSU is permitted, the U.S. Department of Energy (DOE) will ask that NDEP revoke the MCA and onsite-generated LLMW will fall under the MWSU permit terms and conditions. The unit will also store polychlorinated biphenyl (PCB) waste and friable and non-friable asbestos waste that meets the acceptance criteria in the Waste Analysis Plan (Exhibit 2) for disposal in the MWDU. In addition to Resource Conservation and Recovery Act (RCRA) requirements, the proposed MWSU will also be subject to Department of Energy (DOE) orders and other applicable state and federal regulations. Table 1 provides the metric conversion factors used in …
Date: July 19, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
A Review of X-ray Diagnostic Calibrations in the 2 to 100 keV Region Using the High Energy X-ray Calibration Facility (HEX) (open access)

A Review of X-ray Diagnostic Calibrations in the 2 to 100 keV Region Using the High Energy X-ray Calibration Facility (HEX)

The precise and accurate measurement of X-rays in the 2 keV to 100 keV region is crucial to the understanding of HED plasmas and warm dense matter in general. With the emergence of inertially confined plasma facilities as the premier platforms for ICF, laboratory astrophysics, and national security related plasma experiments, the need to calibrate diagnostics in the high energy X-ray regime has grown. At National Security Technologies High Energy X-ray Calibration Facility (HEX) in Livermore, California, X-ray imagers, filter-fluorescer spectrometers, crystal spectrometers, image plates, and nuclear diagnostics are calibrated. The HEX can provide measurements of atomic line radiation, X-ray flux (accuracy within 10%), and X-ray energy (accuracy within 1%). The HEX source is comprised of a commercial 160 kV X-ray tube, a fluorescer wheel, a filter wheel, and a lead encasement. The X-ray tube produces a Tungsten bremsstrahlung spectrum which causes a foil to fluoresce line radiation. To minimize bremsstrahlung in the radiation for calibration we also provide various foils as filters. For experimental purposes, a vacuum box capable of 10{sup -7} Torr, as well as HPGe and CdTe radiation detectors, are provided on an optical table. Most geometries and arrangements can be changed to meet experimental needs.
Date: May 19, 2010
Creator: Ali, Zaheer; Pond, T.; Buckles, R. A.; Maddox, B. R.; Chen, C. D.; DeWald, E. L. et al.
Object Type: Article
System: The UNT Digital Library
RIVER PROTECTION PROJECT MISSION ANALYSIS WASTE BLENDING STUDY (open access)

RIVER PROTECTION PROJECT MISSION ANALYSIS WASTE BLENDING STUDY

Preliminary evaluation for blending Hanford site waste with the objective of minimizing the amount of high-level waste (HLW) glass volumes without major changes to the overall waste retrieval and processing sequences currently planned. The evaluation utilizes simplified spreadsheet models developed to allow screening type comparisons of blending options without the need to use the Hanford Tank Waste Operations Simulator (HTWOS) model. The blending scenarios evaluated are expected to increase tank farm operation costs due to increased waste transfers. Benefit would be derived from shorter operating time period for tank waste processing facilities, reduced onsite storage of immobilized HLW, and reduced offsite transportation and disposal costs for the immobilized HLW.
Date: April 19, 2010
Creator: DH, SHUFORD & G, STEGEN
Object Type: Report
System: The UNT Digital Library
Rnnotator: an automated de novo transcriptome assembly pipeline from stranded RNA-Seq reads (open access)

Rnnotator: an automated de novo transcriptome assembly pipeline from stranded RNA-Seq reads

Background: Comprehensive annotation and quantification of transcriptomes are outstanding problems in functional genomics. While high throughput mRNA sequencing (RNA-Seq) has emerged as a powerful tool for addressing these problems, its success is dependent upon the availability and quality of reference genome sequences, thus limiting the organisms to which it can be applied. Results: Here, we describe Rnnotator, an automated software pipeline that generates transcript models by de novo assembly of RNA-Seq data without the need for a reference genome. We have applied the Rnnotator assembly pipeline to two yeast transcriptomes and compared the results to the reference gene catalogs of these organisms. The contigs produced by Rnnotator are highly accurate (95percent) and reconstruct full-length genes for the majority of the existing gene models (54.3percent). Furthermore, our analyses revealed many novel transcribed regions that are absent from well annotated genomes, suggesting Rnnotator serves as a complementary approach to analysis based on a reference genome for comprehensive transcriptomics. Conclusions: These results demonstrate that the Rnnotator pipeline is able to reconstruct full-length transcripts in the absence of a complete reference genome.
Date: November 19, 2010
Creator: Martin, Jeffrey; Bruno, Vincent M.; Fang, Zhide; Meng, Xiandong; Blow, Matthew; Zhang, Tao et al.
Object Type: Article
System: The UNT Digital Library