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2001 Gordon Research Conference on MYOGENESIS (open access)

2001 Gordon Research Conference on MYOGENESIS

The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.
Date: May 4, 2001
Creator: unknown
System: The UNT Digital Library
Absence of X-point band overlap in divalent hexaborides and variability of the surface chemical potential (open access)

Absence of X-point band overlap in divalent hexaborides and variability of the surface chemical potential

Angle-resolved photoemission measurements of divalent hexaborides reveals a >1 eV X-point gap between the valence and conduction bands, in contradiction to the band overlap assumed in several models of their novel ferromagnetism. While the global ARPES band structure and gap size observed are consistent with the results of bulk-sensitive soft x-ray absorption and emission boron K-edge spectroscopy, the surface-sensitive photoemission measurements also show a variation with cation, surface and time of the position of the surface chemical potential in the band structure.
Date: November 4, 2001
Creator: Denlinger, Jonathan D.; Gweon, Gey-Hong; Mo, Sung-Kwan; Allen, James W.; Sarrao, John L.; Bianchi, Adrian D. et al.
System: The UNT Digital Library
An Analysis of Gas Pressure Forming of Superplastic AL 5083 Alloy (open access)

An Analysis of Gas Pressure Forming of Superplastic AL 5083 Alloy

Al 5083 disks of a superplastic forming grade were gas-pressure formed to hemispheres and cones at constant forming pressures with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of the hemispheres and cones were measured for the different forming and back pressures applied. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to closely follow the flow stress-strain rate relationship obtained from the strain rate change tests performed at the same temperature using uniaxial tensile samples.
Date: May 4, 2001
Creator: Syn, C K; O'Brien, M J; Lesuer, D R & Sherby, O D
System: The UNT Digital Library
Are multiple runs better than one? (open access)

Are multiple runs better than one?

This paper investigates whether it is better to use a certain constant amount of computational resources in a single run with a large population, or in multiple runs with smaller populations. The paper presents the primary tradeoffs involved in this problem and identifies the conditions under which there is an advantage to use multiple small runs. The paper uses an existing model that relates the quality of the solutions reached by a GA with its population size. The results suggest that in most cases a single run with the largest population possible reaches a better solution than multiple isolated runs. The findings are validated with experiments on functions of varying difficulty.
Date: January 4, 2001
Creator: Cantú-Paz, E.
System: The UNT Digital Library
Beauty Physics at CDF (open access)

Beauty Physics at CDF

The CDF experiment has performed several measurements in the area of beauty and charm physics with the data collected during the Run I of the Tevatron. The experiment is now ready to collect new data at higher luminosity with a substantially improved detector. We discuss these improvements and the future measurements in this area of physics accessible after the first few years of data taking. These include the measurement of the mixing frequency of B{sub s} mesons and that of CP violation effects in the B{sub 0} sector.
Date: September 4, 2001
Creator: Bedeschi, Franco
System: The UNT Digital Library
Calculations of carrier localization in In/sub x/Ga/sub 1-x/N (open access)

Calculations of carrier localization in In/sub x/Ga/sub 1-x/N

None
Date: April 4, 2001
Creator: Wang, Lin-Wang
System: The UNT Digital Library
Can we distinguish an MSSM higgs from a SM higgs at a linear collider? (open access)

Can we distinguish an MSSM higgs from a SM higgs at a linear collider?

The authors study the prospects for distinguishing the CP-even Higgs boson of the minimal supersymmetric extension of the Standard Model (MSSM) from the Standard Model (SM) Higgs boson by measuring its branching ratios at an e{sup +}e{sup {minus}} linear collider. The regions of the M{sub A} - tan {beta} plane in which an MSSM Higgs boson can be distinguished from the SM Higgs boson depend strongly upon the supersymmetric parameters that enter the radiative corrections to the Higgs mass matrix and the Higgs couplings to fermions. In some regions of parameter space it is possible to extract the supersymmetric correction to the relation between the b quark mass and its Yukawa coupling from Higgs branching ratio measurements.
Date: January 4, 2001
Creator: Logan, H.E.
System: The UNT Digital Library
Corrosion of glass-bonded sodalite and its components as a function of pH and temperature. (open access)

Corrosion of glass-bonded sodalite and its components as a function of pH and temperature.

None
Date: December 4, 2001
Creator: Jeong, S.-Y.; Morss, L. R. & Ebert, W. L.
System: The UNT Digital Library
Detecting damage in steel with scanning SQUID microscopy (open access)

Detecting damage in steel with scanning SQUID microscopy

A ''Holy Grail'' of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards.
Date: September 4, 2001
Creator: Lee, Tae-Kyu; Clatterbuck, David; Morris Jr., J.W.; Shaw, T.J.; R., McDermott & Clarke, John
System: The UNT Digital Library
Developing a flexible system for multipathway environmental risk analysis. (open access)

Developing a flexible system for multipathway environmental risk analysis.

None
Date: October 4, 2001
Creator: LePoire, D. J.; Arnish, J. J.; Gnanapragasam, E.; Klett, T.; Biwer, B. M.; Johnson, R. L. et al.
System: The UNT Digital Library
Electrical Properties of Sand-Clay Mixtures Containing Trichloroethylene and Ethanol (open access)

Electrical Properties of Sand-Clay Mixtures Containing Trichloroethylene and Ethanol

A series of laboratory experiments, including the measurement of electrical properties and permeability, were performed on carefully characterized sand-clay mixtures. Different mixtures and configurations of quartz sand and 0 to 10% Na-montmorillonite clay were investigated using solutions of NaCl, CaCl{sub 2}, and deionized water. Samples containing 10% distributed clay were also studied using fluids containing 20 and 500 ppm trichloroethylene (TCE). Electrical properties were measured at frequencies between 10{sup 6} and 10{sup -2} Hz using the four-electrode method and Ag-AgCl inner electrodes on saturated samples at room temperature and 412 kPa confining pressure, corresponding to a soil depth of 15 to 20 m. Our results show that the addition of TCE has a small effect on electrical resistivity, with resistivity increasing with the addition of TCE. The influence of TCE on the electrical properties was most prominent in plots of loss tangent as a function of frequency. A loss tangent peak occurred at {approx}200 Hz. The height of the peak and the peak frequency both decrease with the addition of TCE. Further experiments were performed on samples containing a distinct clay layer parallel to current flow. Electrical properties were measured on water saturated samples and as a mixture of ethanol …
Date: December 4, 2001
Creator: Roberts, J. J. & Wildenschild, D.
System: The UNT Digital Library
ESR transmission experiments on {beta}'-(ET){sub 2}SF{sub 5}CF{sub 2}SO{sub 3} and (ET){sub 2}SF{sub 5}NNO{sub 2} investigations of spin-peierls systems. (open access)

ESR transmission experiments on {beta}'-(ET){sub 2}SF{sub 5}CF{sub 2}SO{sub 3} and (ET){sub 2}SF{sub 5}NNO{sub 2} investigations of spin-peierls systems.

None
Date: December 4, 2001
Creator: Rutel, B.; Brooks, J.; Ward, B. H.; VanDerveer, D.; Sitzmann, M. E.; Schlueter, J. et al.
System: The UNT Digital Library
Exploring new physics through contact interactions in lepton pair production at a linear collider (open access)

Exploring new physics through contact interactions in lepton pair production at a linear collider

If a contact interaction type correction to a Standard Model process is observed, studying its detailed properties can provide information on the fundamental physics responsible for it. Assuming that such a correction has been observed in lepton pair production at a 500 GeV-1 TeV linear collider, we consider a few possible models that could explain it, such as theories with large and TeV-scale extra dimensions and models with lepton compositeness. We show that using the measured cross-sections and angular distributions, these models can be distinguished with a high degree of confidence.
Date: December 4, 2001
Creator: Perelstein, Maxim & Pasztor, Gabriella
System: The UNT Digital Library
Fabrication by inclined-substrate deposition of biaxially textured buffer layer for coated conductors. (open access)

Fabrication by inclined-substrate deposition of biaxially textured buffer layer for coated conductors.

None
Date: December 4, 2001
Creator: Balachandran, U.; Ma, B.; Li, M.; Koritala, R. E.; Fisher, B. L.; Erck, R. A. et al.
System: The UNT Digital Library
Future CDF and D0 B Physics (open access)

Future CDF and D0 B Physics

A new period of data taking started on March 2001 for both collaborations CDF and D0. In 2 years around 2 fb{sup -1} of data should be collected by both experiments with a huge number of events containing B mesons available to perform many kinds of measurements. In this paper we discuss our expectations for a few of these measurements. These expectations rely on the experience gained by analyzing the Run I data whenever it is possible and on Monte Carlo otherwise.
Date: September 4, 2001
Creator: Lucchesi, Donatella
System: The UNT Digital Library
GUT breaking on the brane? (open access)

GUT breaking on the brane?

We present a five-dimensional supersymmetric SU(5) theory in which the gauge symmetry is broken maximally (i.e. at the 5D Planck scale M{sub *}) on the same 4D brane where chiral matter is localized. Masses of the lightest Kaluza-Klein modes for the colored Higgs and X and Y gauge fields are determined by the compactification scale of the fifth dimension, M{sub C} {approx} 10{sup 15} GeV, rather than by M{sub *}. These fields' wave functions are repelled from the GUT-breaking brane, so that proton decay rates are suppressed below experimental limits. Above the compactification scale, the differences between the standard model gauge couplings evolve logarithmically, so that ordinary logarithmic gauge coupling unification is preserved. The maximal breaking of the grand unified group can also lead to other effects, such as O(1) deviations from SU(5) predictions of Yukawa couplings, even in models utilizing the Froggatt-Nielsen mechanism.
Date: April 4, 2001
Creator: Smith, David; Nomura, Yasunori & Weiner, Neal
System: The UNT Digital Library
HCCl Combustion: Analysis and Experiments (open access)

HCCl Combustion: Analysis and Experiments

Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model and a multi-zone model. The single zone model has proven very successful in predicting start of combustion and providing reasonable estimates for peak cylinder pressure, indicated efficiency and NOX emissions. This model is being applied to develop detailed engine performance maps and control strategies, and to analyze the problem of engine startability. The multi-zone model is capable of very accurate predictions of the combustion process, including HC and CO emissions. The multi-zone model has applicability to the optimization of combustion chamber geometry and operating conditions to achieve controlled combustion at high efficiency and low emissions. On experimental work, we have done a thorough evaluation of operating conditions in a 4-cylinder Volkswagen TDI engine. The engine has been operated over a wide range of conditions by adjusting the intake …
Date: May 4, 2001
Creator: Aceves, S. M.; Flowers, D. L.; Martinez-Frias, J.; Smith, J. R.; Dibble, R.; Au, M. et al.
System: The UNT Digital Library
High Reflectivity of Silver Extended Down to 200 NM (open access)

High Reflectivity of Silver Extended Down to 200 NM

Silver has the highest reflectance of all of the metals, but it tarnishes in the presence of sulfides, chlorides, and oxides in the atmosphere. Also, the silver reflectance is very low at wavelengths below 400 nm making aluminum more desirable mirror coating for the W region. We have found a way to prevent silver tarnishing by sandwiching the silver layer between two thin layers of NiCrN{sub x}, and to extend the metal's high reflectance down to 200 nm by depositing the (thin) Ag layer on top of Al. Thus, the uv is transmitted through the thin Ag layer below 400 nm wavelength, and is reflected from the A1 layer underneath. This W-shifted durable coating provides a valuable alternative to the aluminum coating for telescope mirror coatings where collection efficiency is an important consideration.
Date: June 4, 2001
Creator: Thomas, N L & Wolfe, J D
System: The UNT Digital Library
Highly Efficient Tabletop Optical Parametric Chirped Pulse Amplifier at 1 (micron)m (open access)

Highly Efficient Tabletop Optical Parametric Chirped Pulse Amplifier at 1 (micron)m

Optical parametric chirped pulse amplification (OPCPA) is a scalable technology, for ultrashort pulse amplification. Its major advantages include design simplicity, broad bandwidth, tunability, low B-integral, high contrast, and high beam quality. OPCPA is suitable both for scaling to high peak power as well as high average power. We describe the amplification of stretched 100 fs oscillator pulses in a three-stage OPCPA system pumped by a commercial, single-longitudinal-mode, Q-switched Nd:YAG laser. The stretched pulses were centered around 1054 nm with a FWHM bandwidth of 16.5 nm and had an energy of 0.5 nJ. Using our OPCPA system, we obtained an amplified pulse energy of up to 31 mJ at a 10 Hz repetition rate. The overall conversion efficiency from pump to signal is 6%, which is the highest efficiency obtained With a commercial tabletop pump laser to date. The overall conversion efficiency is limited due to the finite temporal overlap of the seed (3 ns) with respect to the duration of the pump (8.5 ns). Within the temporal window of the seed pulse the pump to signal conversion efficiency exceeds 20%. Recompression of the amplified signal was demonstrated to 310 fs, limited by the aberrations initially present in the low energy …
Date: December 4, 2001
Creator: Jovanovic, I.; Ebbers, C. A.; Comaskey, B. J.; Bonner, R. A. & Morse, E. C.
System: The UNT Digital Library
Implicit solution of large-scale radiation diffusion problems (open access)

Implicit solution of large-scale radiation diffusion problems

In this paper, we present an efficient solution approach for fully implicit, large-scale, nonlinear radiation diffusion problems. The fully implicit approach is compared to a semi-implicit solution method. Accuracy and efficiency are shown to be better for the fully implicit method on both one- and three-dimensional problems with tabular opacities taken from the LEOS opacity library.
Date: January 4, 2001
Creator: Brown, P N; Graziani, F; Otero, I & Woodward, C S
System: The UNT Digital Library
In-situ TEM - a tool for quantitative observations of deformation behavior in thin films and nano-structured materials (open access)

In-situ TEM - a tool for quantitative observations of deformation behavior in thin films and nano-structured materials

This paper highlights future developments in the field of in-situ transmission electron microscopy, as applied specifically to the issues of deformation in thin films and nanostructured materials. Emphasis is place on the forthcoming technical advances that will aid in extraction of improved quantitative experimental data using this technique.
Date: September 4, 2001
Creator: Stach, E.A.
System: The UNT Digital Library
Influence of the core hole on the KBeta emission following photoionization or orbital electron capture - a comparison using MnO and {sup 55}Fe{sub 2}O{sub 3} (open access)

Influence of the core hole on the KBeta emission following photoionization or orbital electron capture - a comparison using MnO and {sup 55}Fe{sub 2}O{sub 3}

None
Date: August 4, 2001
Creator: Glatzel, Pieter; Bergmann, Uwe; de Groot, Frank M.F. & Cramer, Stephen P.
System: The UNT Digital Library
Integrated fuel processor development. (open access)

Integrated fuel processor development.

The Department of Energy's Office of Advanced Automotive Technologies has been supporting the development of fuel-flexible fuel processors at Argonne National Laboratory. These fuel processors will enable fuel cell vehicles to operate on fuels available through the existing infrastructure. The constraints of on-board space and weight require that these fuel processors be designed to be compact and lightweight, while meeting the performance targets for efficiency and gas quality needed for the fuel cell. This paper discusses the performance of a prototype fuel processor that has been designed and fabricated to operate with liquid fuels, such as gasoline, ethanol, methanol, etc. Rated for a capacity of 10 kWe (one-fifth of that needed for a car), the prototype fuel processor integrates the unit operations (vaporization, heat exchange, etc.) and processes (reforming, water-gas shift, preferential oxidation reactions, etc.) necessary to produce the hydrogen-rich gas (reformate) that will fuel the polymer electrolyte fuel cell stacks. The fuel processor work is being complemented by analytical and fundamental research. With the ultimate objective of meeting on-board fuel processor goals, these studies include: modeling fuel cell systems to identify design and operating features; evaluating alternative fuel processing options; and developing appropriate catalysts and materials. Issues and outstanding …
Date: December 4, 2001
Creator: Ahmed, S.; Pereira, C.; Lee, S. H. D. & Krumpelt, M.
System: The UNT Digital Library
Ion-Irradiation-Induced Amorphization of Cadmium Niobate Pyrochlore (open access)

Ion-Irradiation-Induced Amorphization of Cadmium Niobate Pyrochlore

None
Date: January 4, 2001
Creator: Meldrum, A.
System: The UNT Digital Library