Will at least one of the Higgs bosons of the next-to-minimal supersymmetric extension of the standard model be observable at LEP2 or the LHC? (open access)

Will at least one of the Higgs bosons of the next-to-minimal supersymmetric extension of the standard model be observable at LEP2 or the LHC?

We demonstrate that there are regions of parameter space in the next-to-minimal (i.e. two-Higgs-doublet, one-Higgs-singlet superfield) supersymmetric extension of the SM for which none of the Higgs bosons are observable either at LEP2 with $\sqrt{s}=192 GeV$ and an integrated luminosity of $L=1000inverse pb$ or at the LHC with $L=600 inverse fb$.
Date: June 24, 1996
Creator: Gunion, John F.; Haber, Howard E. & Moroi, Takeo
Object Type: Article
System: The UNT Digital Library
The Salvage Timber Sale Rider: Overview and Policy Issues (open access)

The Salvage Timber Sale Rider: Overview and Policy Issues

The salvage timber rider is actually the Emergency Salvage Timber Sale Program, enacted as �2001 of P.L. 104-19, the 1995 Emergency Supplemental Appropriations and Rescissions Act on July 27, 1995.
Date: June 24, 1996
Creator: Gorte, Ross W.
Object Type: Report
System: The UNT Digital Library
Development of a carburizing and quenching simulation tool: A material model for low carbon steels undergoing phase transformations (open access)

Development of a carburizing and quenching simulation tool: A material model for low carbon steels undergoing phase transformations

An internal state variable formulation for phase transforming alloy steels is presented. We have illustrated how local transformation plasticity can be accommodated by an appropriate choice for the corresponding internal stress field acting between the phases. The state variable framework compares well with a numerical micromechanical calculation providing a discrete dependence of microscopic plasticity on volume fraction and the stress dependence attributable to a softer parent phase. The multiphase model is used to simulate the stress state of a quenched bar and show qualitative trends in the response when the transformation phenomenon is incorporated on the length scale of a global boundary value problem.
Date: June 24, 1996
Creator: Bammann, D.; Prantil, V. & Kumar, A.
Object Type: Article
System: The UNT Digital Library
Farinon microwave end of life cycle (open access)

Farinon microwave end of life cycle

This engineering report evaluates alternatives for the replacement of the Farinon microwave radio system. The system is beyond its expected life cycle and has decreasing maintainability. Principal applications supported by the Farinon system are two electrical utility monitor and control systems, the Integrated Transfer Trip System (ITTS), and the Supervisory Control and Data Acquisition (SCADA) system.
Date: June 24, 1996
Creator: Poe, R. C.
Object Type: Report
System: The UNT Digital Library
Computational modeling of neoclassical and resistive MHD tearing modes in tokamaks (open access)

Computational modeling of neoclassical and resistive MHD tearing modes in tokamaks

Numerical studies of the nonlinear evolution of MHD-type tearing modes in three-dimensional toroidal geometry with neoclassical effects are presented. The inclusion of neoclassical physics introduces an additional free-energy source for the nonlinear formation of magnetic islands through the effects of a bootstrap current in Ohm`s law. The neoclassical tearing mode is demonstrated to be destabilized in plasmas which are otherwise {Delta}` stable, albeit once an island width threshold is exceeded. The plasma pressure dynamics and neoclassical tearing growth is shown to be sensitive to the choice of the ratio of the parallel to perpendicular diffusivity ({Chi}{parallel}/{Chi}{perpendicular}). The study is completed with a demonstration and theoretical comparison of the threshold for single helicity neoclassical MHD tearing modes, which is described based on parameter scans of the local pressure gradient, the ratio of perpendicular to parallel pressure diffusivities {Chi}{perpendicular}/{Chi}{parallel}, and the magnitude of an initial seed magnetic perturbation.
Date: June 24, 1996
Creator: Gianakon, T. A.; Hegna, C. C. & Callen, J. D.
Object Type: Report
System: The UNT Digital Library
Reticle blanks for extreme ultraviolet lithography: Ion beam sputter deposition of low defect density Mo/Si multilayers (open access)

Reticle blanks for extreme ultraviolet lithography: Ion beam sputter deposition of low defect density Mo/Si multilayers

We report on growth of low defect density Mo/Si multilayer (ML) coatings. The coatings were grown in a deposition system designed for EUVL reticle blank fabrication. Complete, 81 layer, high reflectance Mo/Si ML coatings were deposited on 150 mm dia (100) oriented Si wafer substrates using ion beam sputter deposition. Added defects, measured by optical scattering, correspond to defect densities of 2x10{sup -2}/cm{sup 2}. This represents a reduction in defect density of Mo/Si ML coatings by a factor of 10{sup 5}.
Date: June 24, 1996
Creator: Vernon, S.P.; Kania, D.R.; Kearney, P.A.; Levesque, R.A.; Hayes, A.V.; Druz, B. et al.
Object Type: Article
System: The UNT Digital Library
Development of carbon-carbon composites from solvent extracted pitch (open access)

Development of carbon-carbon composites from solvent extracted pitch

There are several methods used to fabricate carbon-carbon composites. One used extensively in the fabrication of aerospace components such as rocket nozzles and reentry vehicle nosetips, as well as commercial components for furnace fixturing and glass manufacturing, is the densification of a woven preform with molten pitch, and the subsequent conversion of the pitch to graphite through heat treatment. Two types of pitch are used in this process; coal tar pitch and petroleum pitch. The objective of this program was to determine if a pitch produced by the direct extraction of coal could be used as a substitute for these pitches in the fabrication of carbon-carbon composites. The program involved comparing solvent extracted pitch with currently accepted pitches and rigidizing a carbon-carbon preform with solvent extracted pitch for comparison with carbon-carbon fabricated with currently available pitch.
Date: June 24, 1996
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Development of a carburizing and quenching simulation tool: Numerical simulations of rings and gears (open access)

Development of a carburizing and quenching simulation tool: Numerical simulations of rings and gears

This paper describes a calculational procedure using the ABAQUS finite element code that simulates a carburizing and quench heat treat cycle for automotive gears. The procedure features a numerically efficient 2-phase constitutive model to represent transformational plasticity effects for the austenite/martensite transformation together with refined finite element meshes to capture the steep gradients in stress and composition near the gear surfaces. The procedure is illustrated on carburizing and quenching of a thick ring, and comparison of model predictions for distortion, phase distribution, and residual stress with experiment is discussed. Sensitivity of predictions to mesh refinement is studied.
Date: June 24, 1996
Creator: Anderson, C.; Goldman, P. & Rangaswamy, P.
Object Type: Article
System: The UNT Digital Library
Atomic structure of the {sigma}5 (210)/[001] symmetric tilt grain boundary in yttrium aluminum garnet (open access)

Atomic structure of the {sigma}5 (210)/[001] symmetric tilt grain boundary in yttrium aluminum garnet

The {Sigma}5(210)/[100] symmetric tilt grain boundary in YAG was produced by UHV diffusion bonding precisely oriented single crystals. The boundary has been characterized by HREM along two different directions, parallel and perpendicular to the tilt axis. Models of the atomic structure of the boundary were formed following the Coincident Site Lattice scheme. The resulting models are equivalent to twins formed at the atomic scale. The high resolution images show no rigid crystal translations away from the perfect mirror reflection relation. Comparison of the simulated images using the atomic model as input with the experimental images identifies the plane of mirror symmetry. The atomic model is shown to be in good agreement with the experimental images when viewed parallel to tilt axis, but disagrees with the images perpendicular to tilt axis. Agreement between simulated and experimental images can be improved by changing the composition of the grain boundary with respect to the bulk. To reach a more certain conclusion on the structure of the grain boundary will require additional theoretical calculations.
Date: June 24, 1996
Creator: Campbell, G. H. & King, W. E.
Object Type: Article
System: The UNT Digital Library
A silicon microbench concept for optoelectronic packaging (open access)

A silicon microbench concept for optoelectronic packaging

Optoelectronics (o/e) is currently too expensive for widespread application. We believe that the packaging (or fiber pigtailing) process must be automated to realize a significant reduction in the cost of o.e packages. We are addressing issues of automating the fiber pigtailing process on silicon waferboards or microbenches. This paper focuses on reflowing solders for the attachment of o/e components. We have recently developed miniature polysilicon heaters which are integrated on silicon microbenches. These miniature heaters avoid the problem of raising the entire microbench to the solder melting point to attach components. Most importantly, these miniature heaters are completely compatible with automating the attachment process. Designing silicon microbenches with on-board heaters requires some care. The thermal properties of the microbench itself along with all coatings and any heatsinking materials must be understood. The heaters must operate in a current and voltage regime compatible with the overall characteristics of the o.e package. Inadvertently reflowing solder in unanticipated locations may occur unless the thermal behavior of the microbench thoroughly known. This paper describes the design and fabrication of our microbenches and an experimental and theoretical study on these silicon microbenches which gives a complete picture of their thermal behavior.
Date: June 24, 1996
Creator: Pocha, M. D.; Strand, O. T. & Kerns, J. A.
Object Type: Article
System: The UNT Digital Library
Natural gas monthly, June 1996 (open access)

Natural gas monthly, June 1996

The natural gas monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. The feature article for this month is Natural Gas Industry Restructuring and EIA Data Collection.
Date: June 24, 1996
Creator: unknown
Object Type: Report
System: The UNT Digital Library
A Regional-Scale GIS-Based Modeling System for Evaluating the Potential Costs and Supplies of Biomass from Biomass Crops (open access)

A Regional-Scale GIS-Based Modeling System for Evaluating the Potential Costs and Supplies of Biomass from Biomass Crops

A GIS-based modeling system was developed for analyzing the geographic variation in potential bioenergy feedstock supplies and optimal locations for siting bioenergy facilities. The modeling system is designed for analyzing individual US states but could readily be adapted to any geographic region.
Date: June 24, 1996
Creator: Graham, R. L.; English, B. C.; Noon, C. E.; Liu, W.; Daly, M. J. & Jager, H. I.
Object Type: Article
System: The UNT Digital Library
Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Final report (open access)

Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Final report

The factors that affect the rate and extent of a model aromatic compound, benzoate, in methanogenic environments was studied. Benzoate is degraded to a threshold concentration below which no further substrate degradation occurs. The threshold concentration depended on the substrate concentration and the amount of acetate present. The threshold value was not a function of the kinetic ability of the organism or toxicity of the end products. Rather a minimal Gibb's free energy value may exist where thermodynamic constraints preclude further benzoate degradation. In addition, new bacterial species were isolated and described, that degrade benzoate or reduce iron, cobalt and other metals.
Date: June 24, 1996
Creator: McInerney, Michael J.
Object Type: Report
System: The UNT Digital Library