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The use of a permanent magnet for water content measurements ofwood chips (open access)

The use of a permanent magnet for water content measurements ofwood chips

The Lawrence Berkeley National Laboratory has developed a device that measures the water content of wood chips, pulp and brown stock for the paper industry. This device employs a permanent magnet as the central part of a NMR measurement system. This report describes the magnet and the NMR measurement system. The results of water content measurements in wood chips in a magnetic field of 0.47 T are presented.
Date: September 20, 2001
Creator: Barale, P. J.; Fong, C. G.; Green, M. A.; Luft, P. A.; McInturff, A. D.; Reimer, J. A. et al.
System: The UNT Digital Library
Limitations of science and adaptive management (open access)

Limitations of science and adaptive management

Adaptive management consists in patterning human sustenancewithin the constraints of Earth and biological systems whose behavior isinherently uncertain and difficult to control. For successful adaptivemanagement, a mind-set recognizing the limitations of science isneeded.
Date: December 20, 2001
Creator: Narasimhan, T.N.
System: The UNT Digital Library
Modeling Large-Strain, High-Rate Deformation in Metals (open access)

Modeling Large-Strain, High-Rate Deformation in Metals

The large strain deformation response of 6061-T6 and Ti-6Al-4V has been evaluated over a range in strain rates from 10{sup -4} s{sup -1} to over 10{sup 4} s{sup -1}. The results have been used to critically evaluate the strength and damage components of the Johnson-Cook (JC) material model. A new model that addresses the shortcomings of the JC model was then developed and evaluated. The model is derived from the rate equations that represent deformation mechanisms active during moderate and high rate loading. Another model that accounts for the influence of void formation on yield and flow behavior of a ductile metal (the Gurson model) was also evaluated. The characteristics and predictive capabilities of these models are reviewed.
Date: July 20, 2001
Creator: Lesuer, D. R.; Kay, G. J. & LeBlanc, M. M.
System: The UNT Digital Library
Measurement of synchrotron pulse durations using surfacephotovoltage transients (open access)

Measurement of synchrotron pulse durations using surfacephotovoltage transients

None
Date: March 20, 2001
Creator: Glover, T. E.; Ackermann, G. D.; Belkacem, A.; Feinberg, B.; Heimann, P. A.; Hussain, Z. et al.
System: The UNT Digital Library
Fluctuation probes of quark deconfinement (open access)

Fluctuation probes of quark deconfinement

Fluctuations in the multiplicities and momentum distributions of particles emitted in relativistic heavy-ion collisions have been widely considered as probes of thermalization and the statistical nature of particle production in such reactions. The characteristic behavior of temperature and pion multiplicity fluctuations in the final state has been proposed as a tool for the measurement of the specific heat and, specifically, for the detection of a critical point in the nuclear matter phase diagram.
Date: June 20, 2001
Creator: Asakawa, M.; Heinz, U. & Muller, B.
System: The UNT Digital Library
The next linear collider damping ring lattices (open access)

The next linear collider damping ring lattices

We report on the lattice design of the Next Linear Collider (NLC) damping rings. The damping rings are required to provide low emittance electron and positron bunch trains to the NLC linacs, at a rate of 120 Hz. We present an optical design, based on a theoretical minimum emittance (TME) lattice, to produce the required normalized extracted beam emittances gex = 3 mm-mrad and gey = 0.02 mm mrad. An assessment of dynamic aperture and non-linear effects is given. The positron pre-damping ring, required to reduce the emittance of the positron beam such that it may be accepted by a main damping ring, is also described.
Date: June 20, 2001
Creator: Wolski, Andrzej & Corlett, John N.
System: The UNT Digital Library
Proton radiation damage in high-resistivity n-type silicon CCDs (open access)

Proton radiation damage in high-resistivity n-type silicon CCDs

A new type of p-channel CCD constructed on high-resistivity n-type silicon was exposed to 12 MeV protons at doses up to 1x1011 protons/cm2. The charge transfer efficiency was measured as a function of radiation dose and temperature. We previously reported that these CCDs are significantly more tolerant to radiation damage than conventional n-channel devices. In the work reported here, we used pocket pumping techniques and charge transfer efficiency measurements to determine the identity and concentrations of radiation induced traps present in the damaged devices.
Date: December 20, 2001
Creator: Bebek, C. J.; Groom, D. E.; Holland, S. E.; Karcher, A.; Kolbe, W. F.; Lee, J. et al.
System: The UNT Digital Library
Inhibition of heregulin expression blocks tumorigenicity and metastasis of breast cancer (open access)

Inhibition of heregulin expression blocks tumorigenicity and metastasis of breast cancer

The growth factor Heregulin (HRG) is expressed in 30% of breast cancer tumors. HRG induces tumorigenicity and metastasis of breast cancer cells. Our investigation into whether blockage of HRG reduces the aggressiveness of breast cancer cells demonstrated that transfection of MDA-MB-231 with an HRG antisense cDNA suppressed proliferation, tumorigenicity, and metastasis. Blockage of the aggressive phenotype is mediated possibly through inactivation of the erbB signaling pathways and a decrease in MMP-9 activity. Our study is the first to report that HRG is a key promoter of breast cancer progression and should be deemed as a potential target in developing therapies for the treatment of breast carcinomas.
Date: December 20, 2001
Creator: Tsai, Miaw-Sheue; Shamon-Taylor, Lisa A.; Mehmi, Inderjit; Tang, Careen K.; Cardillo, Marina & Lupu, Ruth
System: The UNT Digital Library
Application of a Sixth Order Generalized Stress Function To Determine Limit Loads for Plates with Triangular Penetration Patterns (open access)

Application of a Sixth Order Generalized Stress Function To Determine Limit Loads for Plates with Triangular Penetration Patterns

The capabilities to obtain limit load solutions of plates with triangular penetration patterns using fourth order functions to represent the collapse surface has been presented in previous papers. These papers describe how equivalent solid plate elastic-perfectly plastic finite element capabilities are generated and demonstrated how such capabilities can be used to great advantage in the analysis of tubesheets in large heat exchanger applications. However, these papers have pointed out that although the fourth order functions can produce sufficient accuracy for many practical applications, there are situations where improvements in the accuracy of inplane and transverse shear are desirable. This paper investigates the use of a sixth order function to represent the collapse surface for improved accuracy of the inplane response. Explicit elastic-perfectly plastic finite element solutions are obtained for unit cells representing an infinite array of circular penetrations arranged in an equilateral triangular array. These cells are used to create a numerical representation of the complete collapse surfaces for a number of ligament efficiencies (h/P where h is the minimum ligament width and P is the distance between hole centers). Each collapse surface is then fit to a sixth order function that satisfies the periodicity of the hole pattern. Sixth-order …
Date: December 20, 2001
Creator: Gordon, J.L. & Jones, D.P.
System: The UNT Digital Library
Corrosion tests of LWR fuels-nuclide release rates. (open access)

Corrosion tests of LWR fuels-nuclide release rates.

None
Date: December 20, 2001
Creator: Finn, P.A.; Tsai, Y. & Cunnane, J.C.
System: The UNT Digital Library
Self assembled magnetic dots, antidots, dot chains, and stripes : epitaxial Co on Ru (0001). (open access)

Self assembled magnetic dots, antidots, dot chains, and stripes : epitaxial Co on Ru (0001).

None
Date: December 20, 2001
Creator: Li, D. & Yu, C.
System: The UNT Digital Library
Kinetics of electron transfer reactions in hydrothermal and supercritical water. (open access)

Kinetics of electron transfer reactions in hydrothermal and supercritical water.

The rates of several radiation-induced reactions are assessed via pulse radiolysis in order to extend a model for nuclear reactor coolant radiolysis to supercritical conditions. They find changes in radiolysis yields and significant deviations from Arrhenius behavior at 250 bar as the temperature approaches and exceeds the critical temperature of pure water. At 380 C they also observe a strong pressure dependence of the reaction rates of ions and hydrophobic species. Using a homogeneous chemistry model, they find by 350 C that the relatively mild changes in these reaction rates increase the predicted critical hydrogen concentration relative to 325 C.
Date: November 20, 2001
Creator: Cline, J. A.; Takahashi, K.; Marin, T. W.; Jonah, C. D. & Bartels, D. M.
System: The UNT Digital Library
Intelligent monitoring and analysis for safeguards applications. (open access)

Intelligent monitoring and analysis for safeguards applications.

None
Date: December 20, 2001
Creator: Laurin-Kovitz, K.F. & Ewing, T.F.
System: The UNT Digital Library
KAON PHYSICS AT BNL. (open access)

KAON PHYSICS AT BNL.

The rare kaon decay program at BNL is summarized. A brief review of recent results is provided along with a discussion of prospects for the future of this program. The primary focus is the two golden modes: K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} and K{sub L}{sup o} {yields} {pi}{sup o} {nu}{bar {nu}}. The first step in an ambitious program to precisely measure both branching ratios has been successfully completed with the observation of two K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} events by E787. The E949 experiment is poised to reach an order of magnitude further in sensitivity and to observe {approx}10 Standard Model events.
Date: November 20, 2001
Creator: KETTELL,S.H.
System: The UNT Digital Library
Direct index of refraction measurement at extreme ultraviolet wavelength region with a novel interferometer (open access)

Direct index of refraction measurement at extreme ultraviolet wavelength region with a novel interferometer

None
Date: November 20, 2001
Creator: Chang, Chang; Anderson, Erik H.; Naulleau, Patrick P.; Gullikson, Eric; Goldberg, Kenneth A. & Attwood, David T.
System: The UNT Digital Library
The U.S. RIA project SRF linac. (open access)

The U.S. RIA project SRF linac.

None
Date: December 20, 2001
Creator: Shepard, K.W.
System: The UNT Digital Library
Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements (open access)

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements

People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.
Date: March 20, 2001
Creator: Candy, J V & Meyer, A W
System: The UNT Digital Library
PDE-based Non-Linear Diffusion Techniques for Denoising Scientific and Industrial Images: An Empirical Study (open access)

PDE-based Non-Linear Diffusion Techniques for Denoising Scientific and Industrial Images: An Empirical Study

Removing noise from data is often the first step in data analysis. Denoising techniques should not only reduce the noise, but do so without blurring or changing the location of the edges. Many approaches have been proposed to accomplish this; in this paper, they focus on one such approach, namely the use of non-linear diffusion operators. This approach has been studied extensively from a theoretical viewpoint ever since the 1987 work of Perona and Malik showed that non-linear filters outperformed the more traditional linear Canny edge detector. They complement this theoretical work by investigating the performance of several isotropic diffusion operators on test images from scientific domains. They explore the effects of various parameters such as the choice of diffusivity function, explicit and implicit methods for the discretization of the PDE, and approaches for the spatial discretization of the non-linear operator etc. They also compare these schemes with simple spatial filters and the more complex wavelet-based shrinkage techniques. The empirical results show that, with an appropriate choice of parameters, diffusion-based schemes can be as effective as competitive techniques.
Date: December 20, 2001
Creator: Weeratunga, S K & Kamath, C
System: The UNT Digital Library
Study of Positronium in Low-k Dielectric Films by means of 2D-Angular Correlation Experiments at a High-Intensity Slow-Positron Beam (open access)

Study of Positronium in Low-k Dielectric Films by means of 2D-Angular Correlation Experiments at a High-Intensity Slow-Positron Beam

Depth-resolved measurements of the two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed at the high-intensity slow-positron beam of Lawrence Livermore National Laboratory. We studied the formation of positronium in thin films of methyl-silsesquioxane (MSSQ) spin-on glass containing open-volume defects in the size of voids. Samples with different average void sizes were investigated and positronium formation could be found in all cases. The width of the angular correlation related to the annihilation of parapositronium increased with the void size indicating the annihilation of non-thermalized parapositronium.
Date: June 20, 2001
Creator: Gessmann, T; Petkov, M P; Weber, M H; Lynn, K G; Rodbell, K P; Asoka-Kumar, P et al.
System: The UNT Digital Library
Flow and Fracture of Bulk Metallic Glass Alloys and their Composites (open access)

Flow and Fracture of Bulk Metallic Glass Alloys and their Composites

The fracture and plastic deformation mechanisms of a Zr-Ti-Ni-Cu-Be bulk metallic glass and a composite utilizing a crystalline reinforcement phase are reviewed. The relationship between stress state, free volume and shear band formation are discussed. Positron annihilation techniques were used to confirm the predicted increase in free volume after plastic straining. Strain localization and failure were examined for a wide range of stress states. Finally, methods for toughening metallic glasses are considered. Significant increases in toughness are demonstrated for a composite bulk metallic glass containing a ductile second phase which stabilizes shear band formation and distributes plastic deformation.
Date: June 20, 2001
Creator: Flores, K M; Suh, D; Howell, R; Asoka-Kumar, P & Dauskardt, R H
System: The UNT Digital Library
Polarization Studies in Fast-Ion Beam Spectroscopy (open access)

Polarization Studies in Fast-Ion Beam Spectroscopy

In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.
Date: December 20, 2001
Creator: Trabert, E
System: The UNT Digital Library
UV Laser Conditioning for Reduction of 351-nm Damage Initiation in Fused Silica (open access)

UV Laser Conditioning for Reduction of 351-nm Damage Initiation in Fused Silica

This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-induced surface damage sites on large-aperture fused silica optics. We will show the effect of various 355-nm laser conditioning methodologies on the reduction of surface-damage initiation in fused silica samples that have varying qualities of polishing. With the best, generally available fused silica optic, we have demonstrated that 355-nm laser conditioning can achieve up to 10x reduction in surface damage initiation concentration in the fluence range of 10-14 J/cm{sup 2} (355-nm {at} 3 ns).
Date: December 20, 2001
Creator: Brusasco, R. M.; Penetrante, B. M.; Peterson, J. E.; Maricle, S. M. & Menapace, J. A.
System: The UNT Digital Library
Teller Medal Lecture IFSA2001: Problems and Solutions in the Design and Analysis of Early Laser Driven High Energy Density and ICF Target Physics Experiments (open access)

Teller Medal Lecture IFSA2001: Problems and Solutions in the Design and Analysis of Early Laser Driven High Energy Density and ICF Target Physics Experiments

The high energy density (HED) and inertial confinement fusion (ICF) physics community relies on increasingly sophisticated high power laser driven experiments to advance the field. We review early work in the design and analysis of such experiments, and discuss the problems encountered. By finding solutions to those problems we put the field on firmer ground, allowing the community to develop it to the exciting stage it is in today. Specific examples include: drive and preheat in complex hohlraum geometries with the complicating effects of sample motion; and issues in the successful design of laboratory soft x-ray lasers and in the invention of methods to reduce the required optical laser driver energy by several orders of magnitude.
Date: August 20, 2001
Creator: Rosen, M D
System: The UNT Digital Library
Partial Data Traces: Efficient Generation and Representation (open access)

Partial Data Traces: Efficient Generation and Representation

Binary manipulation techniques are increasing in popularity. They support program transformations tailored toward certain program inputs, and these transformations have been shown to yield performance gains beyond the scope of static code optimizations without profile-directed feedback. They even deliver moderate gains in the presence of profile-guided optimizations. In addition, transformations can be performed on the entire executable, including library routines. This work focuses on program instrumentation, yet another application of binary manipulation. This paper reports preliminary results on generating partial data traces through dynamic binary rewriting. The contributions are threefold. First, a portable method for extracting precise data traces for partial executions of arbitrary applications is developed. Second, a set of hierarchical structures for compactly representing these accesses is developed. Third, an efficient online algorithm to detect regular accesses is introduced. The authors utilize dynamic binary rewriting to selectively collect partial address traces of regions within a program. This allows partial tracing of hot paths for only a short time during program execution in contrast to static rewriting techniques that lack hot path detection and also lack facilities to limit the duration of data collection. Preliminary results show reductions of three orders of a magnitude of inline instrumentation over a …
Date: August 20, 2001
Creator: Mueller, F; De Supinski, B R; McKee, S A & Yoo, A
System: The UNT Digital Library