Advanced Motors (open access)

Advanced Motors

Project Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling …
Date: December 14, 2012
Creator: Knoth, Edward A.; Chelluri, Bhanumathi & Schumaker, Edward J.
Object Type: Report
System: The UNT Digital Library
Assssment and Mapping of the Riverine Hydrokinetic Resource in the Continental United States (open access)

Assssment and Mapping of the Riverine Hydrokinetic Resource in the Continental United States

The U.S. Department of Energy (DOE) funded the Electric Power Research Institute and its collaborative partners, University of Alaska ? Anchorage, University of Alaska ? Fairbanks, and the National Renewable Energy Laboratory, to provide an assessment of the riverine hydrokinetic resource in the continental United States. The assessment benefited from input obtained during two workshops attended by individuals with relevant expertise and from a National Research Council panel commissioned by DOE to provide guidance to this and other concurrent, DOE-funded assessments of water based renewable energy. These sources of expertise provided valuable advice regarding data sources and assessment methodology. The assessment of the hydrokinetic resource in the 48 contiguous states is derived from spatially-explicit data contained in NHDPlus ?a GIS-based database containing river segment-specific information on discharge characteristics and channel slope. 71,398 river segments with mean annual flow greater than 1,000 cubic feet per second (cfs) mean discharge were included in the assessment. Segments with discharge less than 1,000 cfs were dropped from the assessment, as were river segments with hydroelectric dams. The results for the theoretical and technical resource in the 48 contiguous states were found to be relatively insensitive to the cutoff chosen. Raising the cutoff to 1,500 …
Date: December 14, 2012
Creator: Jacobson, Paul T.; Ravens, Thomas M.; Cunningham, Keith W. & Scott, George
Object Type: Report
System: The UNT Digital Library
Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope (open access)

Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope

None
Date: December 14, 2012
Creator: Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G. et al.
Object Type: Article
System: The UNT Digital Library
Effect of Thermal Anneal on Growth Behavior of Laser-Induced Damage Sites on the Exit Surface of Fused Silica (open access)

Effect of Thermal Anneal on Growth Behavior of Laser-Induced Damage Sites on the Exit Surface of Fused Silica

None
Date: December 14, 2012
Creator: Raman, R N; Negres, R A; Matthews, M J & Carr, C W
Object Type: Article
System: The UNT Digital Library
Final report for the NSF/DOE partnership in basic plasma science grant DE-FG02-06ER54906 '˜Laser-driven collisionless shocks in the Large Plasma Device'™ (open access)

Final report for the NSF/DOE partnership in basic plasma science grant DE-FG02-06ER54906 '˜Laser-driven collisionless shocks in the Large Plasma Device'™

We have performed several thousand high-energy laser shots in the LAPD to investigate the dynamics of an exploding laser-produced plasma in a large ambient magneto-plasma. Debris-ions expanding at super-Alfvenic velocity (up to MA=1.5) expel the ambient magnetic field, creating a large (> 20 cm) diamagnetic cavity. We observed field compressions of up to B/B{sub 0} = 1.5 at the edge of the bubble, consistent with the MHD jump conditions, as well as localized electron heating at the edge of the bubble. Two-dimensional hybrid simulations reproduce these measurements well and show that the majority of the ambient ions are energized by the magnetic piston to super-Alfvenic speeds and swept outside the bubble volume. Nonlinear shear-Alfven waves ({delta}B/B{sub 0} > 25%) are radiated from the cavity with a coupling efficiency of 70% from magnetic energy in the bubble to the wave. While the data is consistent with a weak magneto-sonic shock, the experiments were severely limited by the low ambient plasma densities (10{sup 12} cm{sup -3}). 2D hybrid simulations indicate that future experiments with the new LAPD plasma source and densities in excess of 10{sup 13} cm{sup -3} will drive full-blown collisionless shocks with MA>10 over several c/wpi and shocked Larmor radii. …
Date: December 14, 2012
Creator: Niemann, Christoph; Gekelman, W.; Winske, D. & Larsen, D.
Object Type: Report
System: The UNT Digital Library
Fundamental Physics at the Intensity Frontier (open access)

Fundamental Physics at the Intensity Frontier

None
Date: December 14, 2012
Creator: Hewett, J. L.; Weerts, H.; Brock, R.; Butler, J. N.; Casey, B. C. K.; Collar, J. et al.
Object Type: Article
System: The UNT Digital Library
Halo-to-Halo Similarity and Scatter in the Velocity Distribution of Dark Matter (open access)

Halo-to-Halo Similarity and Scatter in the Velocity Distribution of Dark Matter

Examines the velocity distribution function (VDF) in dark matter halos from milky way to cluster mass scales.
Date: December 14, 2012
Creator: Mao, Yao-Yuan; Strigari, Louis E.; Wechsler, Risa H.; Wu, Hao-Yi & Hahn, Oliver
Object Type: Article
System: The UNT Digital Library
Institute for Molecular Medicine Research Program (open access)

Institute for Molecular Medicine Research Program

The objectives of the project are the development of new Positron Emission Tomography (PET) imaging instrumentation, chemistry technology platforms and new molecular imaging probes to examine the transformations from normal cellular and biological processes to those of disease in pre-clinical animal models. These technology platforms and imaging probes provide the means to: 1. Study the biology of disease using pre-clinical mouse models and cells. 2. Develop molecular imaging probes for imaging assays of proteins in pre-clinical models. 3. Develop imaging assays in pre-clinical models to provide to other scientists the means to guide and improve the processes for discovering new drugs. 4. Develop imaging assays in pre-clinical models for others to use in judging the impact of drugs on the biology of disease.
Date: December 14, 2012
Creator: Phelps, Michael E.
Object Type: Report
System: The UNT Digital Library
Lightweight Aluminum/Nano composites for Automotive Drive Train Applications (open access)

Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter parts have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to …
Date: December 14, 2012
Creator: Chelluri, Bhanumathi; Knoth, Edward A. & Schumaker, Edward J.
Object Type: Report
System: The UNT Digital Library
Multiscale framework for predicting the coupling between deformation and fluid diffusion in porous rocks (open access)

Multiscale framework for predicting the coupling between deformation and fluid diffusion in porous rocks

In this project, a predictive multiscale framework will be developed to simulate the strong coupling between solid deformations and fluid diffusion in porous rocks. We intend to improve macroscale modeling by incorporating fundamental physical modeling at the microscale in a computationally efficient way. This is an essential step toward further developments in multiphysics modeling, linking hydraulic, thermal, chemical, and geomechanical processes. This research will focus on areas where severe deformations are observed, such as deformation bands, where classical phenomenology breaks down. Multiscale geometric complexities and key geomechanical and hydraulic attributes of deformation bands (e.g., grain sliding and crushing, and pore collapse, causing interstitial fluid expulsion under saturated conditions), can significantly affect the constitutive response of the skeleton and the intrinsic permeability. Discrete mechanics (DEM) and the lattice Boltzmann method (LBM) will be used to probe the microstructure---under the current state---to extract the evolution of macroscopic constitutive parameters and the permeability tensor. These evolving macroscopic constitutive parameters are then directly used in continuum scale predictions using the finite element method (FEM) accounting for the coupled solid deformation and fluid diffusion. A particularly valuable aspect of this research is the thorough quantitative verification and validation program at different scales. The multiscale homogenization …
Date: December 14, 2012
Creator: Andrade, José E & Rudnicki, John W
Object Type: Report
System: The UNT Digital Library
Observation of Supernova Remnant IC 443 with the Fermi Large Area Telescope (open access)

Observation of Supernova Remnant IC 443 with the Fermi Large Area Telescope

None
Date: December 14, 2012
Creator: Abdo, A. A.
Object Type: Report
System: The UNT Digital Library
OpenAtom: Ab initio Molecular Dynamics for Petascale Platforms (open access)

OpenAtom: Ab initio Molecular Dynamics for Petascale Platforms

None
Date: December 14, 2012
Creator: Martyna, G. J.; Bohm, E. J.; Venkataraman, R.; Arya, A.; Kale, L. V. & Bhatele, A.
Object Type: Book
System: The UNT Digital Library
Scalable Molecular Dynamics with NAMD (open access)

Scalable Molecular Dynamics with NAMD

None
Date: December 14, 2012
Creator: Phillips, J. C.; Schulten, K.; Bhatele, A.; Mei, C.; Sun, Y. & Kale, L. V.
Object Type: Book
System: The UNT Digital Library
Systematic Uncertainties in NLO PS Matching (open access)

Systematic Uncertainties in NLO PS Matching

None
Date: December 14, 2012
Creator: Schonherr, Marek; Hoeche, Stefan; Krauss, Frank & Siegert, Frank
Object Type: Article
System: The UNT Digital Library
Uncertainties in NLO + Parton Shower Matched Simulations of Inclusive Jet and Dijet Production (open access)

Uncertainties in NLO + Parton Shower Matched Simulations of Inclusive Jet and Dijet Production

None
Date: December 14, 2012
Creator: Hoeche, Stefan & Schonherr, Marek
Object Type: Article
System: The UNT Digital Library
W+n-jet Predictions at NLO Matched with a Parton Shower (open access)

W+n-jet Predictions at NLO Matched with a Parton Shower

None
Date: December 14, 2012
Creator: Siegert, Frank; Hoeche, Stefan; Krauss, Frank & Schonherr, Marek
Object Type: Article
System: The UNT Digital Library
2D Optical Streaking for Ultra-Short Electron Beam Diagnostics (open access)

2D Optical Streaking for Ultra-Short Electron Beam Diagnostics

We propose a novel approach to measure short electron bunch profiles at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a downstream screen where the angular modulation is converted to a circular shape. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and experimental consideration of this method are discussed. At Linac Coherent Light Source (LCLS), an S-band RF transverse deflector (TCAV) is used to measure the bunch length with a resolution 10 femtosecond (fs) rms. An X-band deflector (wavelength 2.6cm) is proposed recently to improve the resolution. However, at the low charge operation mode (20pC), the pulse length can be as short as fs. It is very challenging to measure femtosecond and sub-femtosecond level bunch length. One of the methods is switching from RF to {mu}m level wavelength laser to deflect the bunch. A powerful laser ({approx}10s GW) is required …
Date: December 14, 2011
Creator: Ding, Y.T.; Huang, Z. & Wang, L.
Object Type: Article
System: The UNT Digital Library
Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations. (open access)

Aerosol Absorption and Scattering Measurements: Field Measuremnets and Laboratory Characterizations.

The objective of this report is to determine the overall impact of atmospheric aerosols on radioactive balance.
Date: December 14, 2011
Creator: Marley, Nancy A. & Gaffney, Jeffrey S.
Object Type: Report
System: The UNT Digital Library
Criticality Safety Analysis on the Mixed Be, Nat-U, and C (Graphite) Reflectors in 55-Gallon Waste Drums and Their Equivalents for HWM Applications (open access)

Criticality Safety Analysis on the Mixed Be, Nat-U, and C (Graphite) Reflectors in 55-Gallon Waste Drums and Their Equivalents for HWM Applications

The objective of this analysis is to develop and establish the technical basis on the criticality safety controls for the storage of mixed beryllium (Be), natural uranium (Nat-U), and carbon (C)/graphite reflectors in 55-gallon waste containers and/or their equivalents in Hazardous Waste Management (HWM) facilities. Based on the criticality safety limits and controls outlined in Section 3.0, the operations involving the use of mixed-reflector drums satisfy the double-contingency principle as required by DOE Order 420.1 and are therefore criticality safe. The mixed-reflector mass limit is 120 grams for each 55-gallon drum or its equivalent. a reflector waiver of 50 grams is allowed for Be, Nat-U, or C/graphite combined. The waived reflectors may be excluded from the reflector mass calculations when determining if a drum is compliant. The mixed-reflector drums are allowed to mix with the typical 55-gallon one-reflector drums with a Pu mass limit of 120 grams. The fissile mass limit for the mixed-reflector container is 65 grams of Pu equivalent each. The corresponding reflector mass limits are 300 grams of Be, and/or 100 kilograms of Nat-U, and/or 110 kilograms of C/graphite for each container. All other unaffected control parameters for the one-reflector containers remain in effect for the mixed-reflector …
Date: December 14, 2011
Creator: Chou, P
Object Type: Report
System: The UNT Digital Library
Criticality Safety Controls for 55-Gallon Drums with a Mass Limit of 200 grams Pu-239 (open access)

Criticality Safety Controls for 55-Gallon Drums with a Mass Limit of 200 grams Pu-239

The following 200-gram Pu drum criticality safety controls are applicable to RHWM drum storage operations: (1) Mass (Fissile/Pu) - each 55-gallon drum or its equivalent shall be limited to 200 gram Pu or Pu equivalent; (2) Moderation - Hydrogen materials with a hydrogen density greater than that (0.133 g H/cc) of polyethylene and paraffin are not allowed and hydrogen materials with a hydrogen density no greater than that of polyethylene and paraffin are allowed with unlimited amounts; (3) Interaction - a spacing of 30-inches (76 cm) is required between arrays and 200-gram Pu drums shall be placed in arrays for 200-gram Pu drums only (no mingling of 200-gram Pu drums with other drums not meeting the drum controls associated with the 200-gram limit); (4) Reflection - no beryllium and carbon/graphite (other than the 50-gram waiver amount) is allowed, (note that Nat-U exceeding the waiver amount is allowed when its U-235 content is included in the fissile mass limit of 200 grams); and (5) Geometry - drum geometry, only 55-gallon drum or its equivalent shall be used and array geometry, 55-gallon drums are allowed for 2-high stacking. Steel waste boxes may be stacked 3-high if constraint.
Date: December 14, 2011
Creator: Chou, P
Object Type: Report
System: The UNT Digital Library
Criticality Safety Evaluations on the Use of 200-gram Pu Mass Limit for RHWM Waste Storage Operations (open access)

Criticality Safety Evaluations on the Use of 200-gram Pu Mass Limit for RHWM Waste Storage Operations

This work establishes the criticality safety technical basis to increase the fissile mass limit from 120 grams to 200 grams for Type A 55-gallon drums and their equivalents. Current RHWM fissile mass limit is 120 grams Pu for Type A 55-gallon containers and their equivalent. In order to increase the Type A 55-gallon drum limit to 200 grams, a few additional criticality safety control requirements are needed on moderators, reflectors, and array controls to ensure that the 200-gram Pu drums remain criticality safe with inadvertent criticality remains incredible. The purpose of this work is to analyze the use of 200-gram Pu drum mass limit for waste storage operations in Radioactive and Hazardous Waste Management (RHWM) Facilities. In this evaluation, the criticality safety controls associated with the 200-gram Pu drums are established for the RHWM waste storage operations. With the implementation of these criticality safety controls, the 200-gram Pu waste drum storage operations are demonstrated to be criticality safe and meet the double-contingency-principle requirement per DOE O 420.1.
Date: December 14, 2011
Creator: Chou, P
Object Type: Report
System: The UNT Digital Library
Final Report for research grant "Development of Methods for High Specific Activity Labeling of Biomolecules Using Astatine-211 in Different Oxidation States" (open access)

Final Report for research grant "Development of Methods for High Specific Activity Labeling of Biomolecules Using Astatine-211 in Different Oxidation States"

The overall objective of this research effort was to develop methods for labeling biomolecules with higher oxidation state species of At-211. This was to be done in an effort to develop reagents that had higher in vivo stability than the present carbon-bonded At-211-labeled compounds. We were unsuccessful in that effort, as none of the approaches studied provided reagents that were stable to in vivo deastatination. However, we gained a lot of information about At-211 in higher oxidation states. The studies proved to be very difficult as small changes in pH and other conditions appeared to change the nature of the species that obtained (by HPLC retention time analyses), with many of the species being unidentifiable. The fact that there are no stable isotopes of astatine, and the chemistry of the nearest halogen iodine is quite different, made it very difficult to interpret results of some experiments. With that said, we believe that a lot of valuable information was obtained from the studies. The research effort evaluated: (1) methods for chemical oxidation of At-211, (2) approaches to chelation of oxidized At-211, and (3) approaches to oxidation of astatophenyl compounds. A major hurdle that had to be surmounted to conduct the research …
Date: December 14, 2011
Creator: Wilbur, D., Scott
Object Type: Report
System: The UNT Digital Library
Observation of Beam ION Instability in Spear3 (open access)

Observation of Beam ION Instability in Spear3

Weak vertical coupled bunch instability with oscillation amplitude at {mu}m level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail. In an electron accelerator, ions generated from the residual gas molecules can be trapped by the beam. Then these trapped ions interact resonantly with the beam and cause beam instability and emittance blow-up. Most existing light sources use a long single bunch train filling pattern, followed by a long gap to avoid multi-turn ion trapping. However, such a gap does not preclude ions from accumulating during one passage of the single bunch train beam, and those ions can still cause a Fast Ion Instability …
Date: December 14, 2011
Creator: Teytelman, D.; Cai, Y.; Corbett, W. J.; Raubenheimer, T. O.; Safranek, J. A.; Schmerge, J. F. et al.
Object Type: Article
System: The UNT Digital Library
An Optical Streaking Method for Measuring Femtosecond Electron Bunches (open access)

An Optical Streaking Method for Measuring Femtosecond Electron Bunches

The measurement of the ultra-short electron bunch length on the femtosecond time scale constitutes a very challenging problem. In the x-ray free electron laser facilities such as the Linac Coherent Light Source, generation of a sub-ten femtoseconds electron beam with 20pC charge is possible, but direct measurements are very difficult due to the resolution limit of the present diagnostics. We propose a new method here based on the measurement of the electron beam energy modulation induced from laser-electron interaction in a short wiggler. A typical optical streaking method requires a laser wavelength much longer than the electron bunch length. In this paper a laser with its wavelength shorter than the electron bunch length has been adopted, while the slope on the laser intensity envelope is used to distinguish the different periods. With this technique it is possible to reconstruct the bunch longitudinal profile from a single shot measurement. Generation of ultrashort x-ray pulses at femtoseconds (fs) scale is of great interest within synchrotron radiation and free electron laser (FEL) user community. One of the simple methods is to operate the FEL facility at low charge. At the Linac Coherent Light Source (LCLS), we have demonstrated the capability of generating ultrashort …
Date: December 14, 2011
Creator: Ding, Yuantao; Bane, Karl L.F. & Huang, Zhirong
Object Type: Article
System: The UNT Digital Library