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Fabrication of high-density cantilever arrays and through-wafer interconnects (open access)

Fabrication of high-density cantilever arrays and through-wafer interconnects

Processes to fabricate dense, dry released microstructures with electrical connections on the opposite side of the wafer are described. A 10 x 10 array of silicon and polysilicon cantilevers with high packing density (5 tips/mm<sup>2</sup>) and high uniformity (<10 µm length variation across the wafer) are demonstrated. The cantilever release process uses a deep SF<sub>6</sub>/C<sub>4</sub>F<sub>8</sub>, plasma etch followed by a HBr plasma etch to accurately release cantilevers. A process for fabricating electrical contacts through the backside of the wafer is also described. Electrodeposited resist, conformal CVD metal deposition and deep SF<sub>6</sub>/C<sub>4</sub>F<sub>8</sub> plasma etching are used to make 30 µm/side square vias each of which has a resistance of 50 m(omega).
Date: November 3, 1998
Creator: A. Harley, J.; Abdollahi-Alibeik, S.; Chow, E. M.; Kenney, T. W.; McCarthy, A. M.; McVittie, J. P. et al.
System: The UNT Digital Library
Extending Performance and Evaluating Risks of PV Systems Failure Using a Fault Tree and Event Tree Approach: Analysis of the Possible Application (open access)

Extending Performance and Evaluating Risks of PV Systems Failure Using a Fault Tree and Event Tree Approach: Analysis of the Possible Application

Performance and reliability of photovoltaic (PV) systems are important issues in the overall evaluation of a PV plant and its components. While performance is connected to the amount of energy produced by the PV installation in the working environmental conditions, reliability impacts the availability of the system to produce the expected amount of energy. In both cases, the evaluation should be done considering information and data coming from indoor as well as outdoor tests. In this paper a way of re-thinking performance, giving it a probabilistic connotation, and connecting the two concepts of performance and reliability is proposed. The paper follows a theoretical approach and discusses the way to obtaining such information, facing benefits and problems. The proposed probabilistic performance accounts for the probability of the system to function correctly, thus passing through the complementary evaluation of the probability of system malfunctions and consequences. Scenarios have to be identified where the system is not functioning properly or at all. They are expected to be combined in a probabilistic safety analysis (PSA) based approach, providing not only the required probability, but also being capable of giving a prioritization of the risks and the most dominant scenario associated to a specific situation. …
Date: June 3, 2012
Creator: A., Colli
System: The UNT Digital Library
A MOBILE MELT-DILUTE MODULE FOR THE TREATMENT OF ALUMINUM RESEARCH REACTOR SPENT FUEL (open access)

A MOBILE MELT-DILUTE MODULE FOR THE TREATMENT OF ALUMINUM RESEARCH REACTOR SPENT FUEL

A mobile melt-dilute (MMD) module for the treatment of aluminum research reactor spent fuel is being developed jointly by the Savannah River National Laboratory and Argonne National Laboratory. The process uses a closed system approach to retain fission products/gases inside a sealed canister after treatment. The MMD process melts and dilutes spent fuel with depleted uranium to obtain an isotopic content of less than 20 percent. The final ingot is solidified inside the sealed canister and can be stored safely either wet or dry until final disposition or reprocessing. The MMD module can be staged at or near the research reactor fuel storage sites to facilitate the melt-dilute treatment of the spent fuel into a stable non-proliferable form.
Date: November 3, 2004
Creator: ADAMS, THAD
System: The UNT Digital Library
Limits on the Production of the Standard Model Higgs Boson in $Pp$ Collisions at $\sqrt{s}=7$ TeV with the ATLAS Detector (open access)
Measurement of the $\upsilon_{1S}$ Production Cross-Section in $Pp$ Collisions at $\sqrt{s} = 7 TeV in ATLAS (open access)

Measurement of the $\upsilon_{1S}$ Production Cross-Section in $Pp$ Collisions at $\sqrt{s} = 7 TeV in ATLAS

None
Date: June 3, 2013
Creator: Aad, Georges
System: The UNT Digital Library
The ATLAS level 2 trigger supervisor. (open access)

The ATLAS level 2 trigger supervisor.

This paper presents an overview of the hardware and software proposed for the ATLAS level 2 Trigger ROI Builder/Supervisor. The essential requirements of this system are that it operate at the design Level 1 Trigger rate of 100kHz and that it support the technical requirements of the architectures suggested for the ATLAS Level 2 Trigger. Commercial equipment and software support are used to the maximum extent possible, with support from dedicated hardware. Timing requirements and latencies are discussed and simulation results are presented.
Date: April 3, 1997
Creator: Abolins, M.; Blair, R. E.; Dawson, J. W.; Owen, D.; Pope, B. G.; Schlereth, J. L. et al.
System: The UNT Digital Library
2006 Electrochemistry Gordon Research Conference - February 12-17-2006 (open access)

2006 Electrochemistry Gordon Research Conference - February 12-17-2006

This report is a descriptive journey of 2006 Electrochemistry Gordon Research Conference.
Date: April 3, 2007
Creator: Abruna, Hector D.
System: The UNT Digital Library
Vehicular Storage of Hydrogen in Insulated Pressure Vessels (open access)

Vehicular Storage of Hydrogen in Insulated Pressure Vessels

This paper describes the development of an alternative technology for storing hydrogen fuel onboard automobiles. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept cryogenic liquid fuel, cryogenic compressed gas or compressed gas at ambient temperature. Insulated pressure vessels offer advantages over conventional H{sub 2} storage approaches. Insulated pressure vessels are more compact and require less carbon fiber than GH{sub 2} vessels. They have lower evaporative losses than LH{sub 2} tanks, and are much lighter than metal hydrides. After outlining the advantages of hydrogen fuel and insulated pressure vessels, the paper describes the experimental and analytical work conducted to verify that insulated pressure vessels can be used safely for vehicular H{sub 2} storage. The paper describes tests that have been conducted to evaluate the safety of insulated pressure vessels. Insulated pressure vessels have successfully completed a series of DOT, ISO and SAE certification tests. A draft procedure for insulated pressure vessel certification has been generated to assist in a future commercialization of this technology. An insulated pressure vessel has been installed in a hydrogen fueled truck and it is currently being subjected to extensive testing.
Date: January 3, 2005
Creator: Aceves, S. M.; Berry, G. D.; Martinez-Frias, J. & Espinosa-Loza, F.
System: The UNT Digital Library
Performance and Certification Testing of Insulated Pressure Vessels for Vehicular Hydrogen Storage (open access)

Performance and Certification Testing of Insulated Pressure Vessels for Vehicular Hydrogen Storage

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.
Date: June 3, 2001
Creator: Aceves, S. M.; Martinez-Frias, J.; Garcia-Villazana, O. & Espinosa-Loza, F.
System: The UNT Digital Library
U-Th/He age of phenocrystic garnet from the 79AD eruption of Mt. Vesuvius (open access)

U-Th/He age of phenocrystic garnet from the 79AD eruption of Mt. Vesuvius

None
Date: November 3, 2003
Creator: Aciego, Sarah; Kennedy, B. M.; DePaolo, Donald J.; Christensen, John N. & Hutcheon, Ian
System: The UNT Digital Library
Comments Regarding "Study of Molecular Interactions in Binary Mixtures of Formamide with 2-Methoxyethanol and 2-Ethoxyethanol at Varying Temperatures" (open access)

Comments Regarding "Study of Molecular Interactions in Binary Mixtures of Formamide with 2-Methoxyethanol and 2-Ethoxyethanol at Varying Temperatures"

This article provides comments on "Study of Molecular Interactions in Binary Mixtures of Formamide with 2-Methoxyethanol and 2-Ethoxyethanol at Varying Temperatures," published in 'Physics and Chemistry of Liquids,' 2013.
Date: June 3, 2013
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Analysis of compression behavior of a [011] Ta single crystal with orientation imaging microscopy and crystal plasticity (open access)

Analysis of compression behavior of a [011] Ta single crystal with orientation imaging microscopy and crystal plasticity

High-purity tantalum single crystal cylinders oriented with [011] parallel to the cylinder axis were deformed 10, 20, and 30 percent in compression. The engineering stress-strain curve exhibited an up-turn at strains greater than {approximately}20% while the samples took on an ellipsoidal shape during testing, elongated along the [100] direction with almost no dimensional change along [0{bar 1}1]. Two orthogonal planes were selected for characterization using Orientation Imaging Microscopy (OIM): one plane containing [100] and [011] (longitudinal) and the other in the plane containing [0{bar 1}1] and [011] (transverse). OIM revealed patterns of alternating crystal rotations that develop as a function of strain and exhibit evolving length scales. The spacing and magnitude of these alternating misorientations increases in number density and decreases in spacing with increasing strain. Classical crystal plasticity calculations were performed to simulate the effects of compression deformation with and without the presence of friction. The calculated stress-strain response, local lattice reorientations, and specimen shape are compared with experiment.
Date: February 3, 1999
Creator: Adams, B. L.; Campbell, G. H.; King, W. E.; Lassila, D. H.; Stolken, J. S.; Sun, S. et al.
System: The UNT Digital Library
Micromilling of Metal Alloys with Focused Ion Beam-Fabricated Tools (open access)

Micromilling of Metal Alloys with Focused Ion Beam-Fabricated Tools

None
Date: October 3, 2000
Creator: Adams, D.P.; Vasile, M.J.; Benavides, G.L. & Campbell, A.N.
System: The UNT Digital Library
Atomic Line Shapes in the Presence of an External Magnetic Field (open access)

Atomic Line Shapes in the Presence of an External Magnetic Field

Both the theoretical basis and computational approach for extending the capabilities of a spectral line broadening code are presented. Following standard line broadening theory, the effects of an external magnetic field are incorporated into the atomic Hamiltonian and plasma average. In the presence of an external magnetic field the atomic Hamiltonian angular properties are altered--atomic energy levels are perturbed and the spectral emission line is polarized. The magnetic field introduces a preferential axis that changes the plasma average. These extensions have been incorporated into a new spectral line broadening code that is applied to several problems of importance to the understanding of tokamak edge plasmas. Applications fall into two broad categories: (1) determination of local plasma properties from distinct line shape features; and (2) consideration of global plasma phenomenon, such as radiation transport. Observable features of the Zeeman effect make H{sub {alpha}} a good magnetic field diagnostic. H{sub {beta}} does not make a good electron density diagnostic since the Zeeman effect is comparable to the Stark effect for a majority of tokamak edge plasma conditions. When optically thick lines exist the details of the spectral line shapes are shown to significantly influence the transport of radiation throughout the system.
Date: July 3, 2002
Creator: Adams, M L; Lee, R W; Scott, H A; Chung, H K & Klein, L
System: The UNT Digital Library
DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK (open access)

DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK

In support of Hanford's feed delivery of high level waste (HLW) to the Waste Treatment and Immobilization Plant (WTP), pilot-scale testing and demonstrations with simulants containing cohesive particles were performed as a joint collaboration between Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL) staff. The objective of the demonstrations was to determine the impact that cohesive particle interactions in the simulants, and the resulting non-Newtonian rheology, have on tank mixing and batch transfer of large and dense seed particles. The work addressed the impacts cohesive simulants have on mixing and batch transfer performance in a pilot-scale system. Kaolin slurries with a range of wt% concentrations to vary the Bingham yield stress were used in all the non-Newtonian simulants. To study the effects of just increasing the liquid viscosity (no yield stress) on mixing and batch transfers, a glycerol/water mixture was used. Stainless steel 100 micron particles were used as seed particles due to their density and their contrasting color to the kaolin and glycerol. In support of Hanford's waste certification and delivery of tank waste to the Waste Treatment and Immobilization Plant (WTP), Savannah River National Laboratory (SRNL) was tasked by Washington River Protection Solutions (WRPS) …
Date: January 3, 2012
Creator: Adamson, D. & Gauglitz, P.
System: The UNT Digital Library
Scalable, top-down optical lithography for electrically contacting monolayer crystallites of vapor grown WSe2 for gas sensing applications (open access)

Scalable, top-down optical lithography for electrically contacting monolayer crystallites of vapor grown WSe2 for gas sensing applications

Article discusses how semiconducting two-dimensional transition-metal dichalcogenides (TMDs) have garnered a great deal of interest owing to their large surface-to-volume ratios compared to traditional three-dimensional (3D) semiconductors, and focuses on a specific TMD; tungsten diselenide (WSeâ‚‚). In their study, the authors demonstrate the halide-assisted low-pressure chemical vapor deposition (HA-LPCVD) of high crystalline-quality, monolayer WSeâ‚‚.
Date: October 3, 2022
Creator: Ademaj, Ideal; Mather, Thomas; Jayanand, Kishan & Kaul, Anupama
System: The UNT Digital Library
Electrode and electrolyte configurations for low frequency motion energy harvesting based on reverse electrowetting (open access)

Electrode and electrolyte configurations for low frequency motion energy harvesting based on reverse electrowetting

This article explores various combinations of electrolyte concentrations, dielectrics, and dielectric thicknesses to generate maximum output power employing REWOD energy harvester with the objective of implementing a fully self-powered wearable sensor.
Date: March 3, 2021
Creator: Adhikari, Pashupati R.; Tasneem, Nishat Tarannum; Reid, Russell C. & Mahbub, Ifana
System: The UNT Digital Library
Identification of Pueraria spp. through DNA barcoding and comparative transcriptomics (open access)

Identification of Pueraria spp. through DNA barcoding and comparative transcriptomics

This article presents research where various kudzu accessions were analyzed through barcoding and comparative transcriptomics, generating tools for identification and molecular pathway analysis.
Date: January 3, 2022
Creator: Adolfo, Laci M.; Rao, Xiaolan & Dixon, R. A.
System: The UNT Digital Library
ILC RF System R and D (open access)

ILC RF System R and D

The Linac Group at SLAC is actively pursuing a broad range of R&amp;D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system proposed for the ILC linacs. Current activities include the long-term evaluation of a 120 kV Marx Modulator driving a 10 MW Multi-Beam Klystron, design of a second-generation Marx Modulator, testing of a sheet-beam gun and beam transport system for a klystron, construction of an rf distribution system with remotely-adjustable power tapoffs, and development of a system to combine the power from many klystrons in low-loss circular waveguide where it would be tapped-off periodically to power groups of cavities. This paper surveys progress during the past few years.
Date: July 3, 2012
Creator: Adolphsen, Chris
System: The UNT Digital Library
Atomic electron correlations in intense laser fields (open access)

Atomic electron correlations in intense laser fields

Abstract. This talk examines two distinct cases in strong opbical fields where electron correlation plays an important role in the dynamic.s. In the first. example, strong coupling in a two-electron-like system is manifested as an intensity-dependent splitting in the ionized electron energy distribution. This two-electron phenomenon (dubbed continuum-continuum Autler-Townes effect) is analogous to a strongly coupled two- level, one-electron atom but raises some intriguing questions regarding the exact nature of electron-electron correlation. The second case examines the evidence for two-electron ionization in the strong-field tunneling limit. Although our ability to describe the one- electron dynamics has obtained a quantitative level of understanding, a description of the two (multiple) electron ionization remains unc
Date: September 3, 1998
Creator: Agostini, P. A.; DiMauro, L. F.; Kulander, K.; Sheehy, B. & Walker, B.
System: The UNT Digital Library
Supercritical Stability, Transitions, and (Pseudo)tachyons (open access)

Supercritical Stability, Transitions, and (Pseudo)tachyons

Highly supercritical strings (c &gt;&gt; 15) with a time-like linear dilaton provide a large class of solutions to string theory, in which closed string tachyon condensation is under control (and follows the worldsheet renormalization group flow). In this note we analyze the late-time stability of such backgrounds, including transitions between them. The large friction introduced by the rolling dilaton and the rapid decrease of the string coupling suppress the back-reaction of naive instabilities. In particular, although the graviton, dilaton, and other light fields have negative effective mass squared in the linear dilaton background, the decaying string coupling ensures that their condensation does not cause large back-reaction. Similarly, the copious particles produced in transitions between highly supercritical theories do not back-react significantly on the solution. We discuss these features also in a somewhat more general class of time-dependent backgrounds with stable late-time asymptotics.
Date: January 3, 2007
Creator: Aharony, Ofer & Silverstein, Eva
System: The UNT Digital Library
Safeguards Effectiveness Evaluations in Safeguards Planning (open access)

Safeguards Effectiveness Evaluations in Safeguards Planning

This paper describes analytic tools we developed to quantify the effectiveness of safeguards against theft of special nuclear material by insiders. These tools help identify vulnerabilities in existing safeguards, suggest potential improvements, and help assess the benefits of these upgrades prior to implementation. Alone, these tools are not sufficient for safeguards planning, since the cost of implementing all suggested upgrades almost always exceeds the available resources. This paper describes another tool we developed to allow comparsion of benefits of various upgrades to identify those upgrade packages that achieve the greatest improvement in protection for a given cost and to provide a priority ranking among cost-effective packages, thereby helping decision-makers select the upgrades to implement and highlight the mount of residual risk. 5 refs., 3 figs.
Date: December 3, 1987
Creator: Al-Ayat, R. A.
System: The UNT Digital Library
Snapping Supernovae at z&gt;1.7 (open access)

Snapping Supernovae at z&gt;1.7

We examine the utility of very high redshift Type Ia supernovae for cosmology and systematic uncertainty control. Next generation space surveys such as the Supernova/Acceleration Probe (SNAP) will obtain thousands of supernovae at z&gt;1.7, beyond the design redshift for which the supernovae will be exquisitely characterized. We find that any z gtrsim 2 standard candles' use for cosmological parameter estimation is quite modest and subject to pitfalls; we examine gravitational lensing, redshift calibration, and contamination effects in some detail. The very high redshift supernovae - both thermonuclear and core collapse - will provide copious interesting information on star formation, environment, and evolution. However, the new observational systematics that must be faced, as well as the limited expansion of SN-parameter space afforded, does not point to high value for 1.7&lt;z&lt;3 SNe Ia in controlling evolutionary systematics relative to what SNAP can already achieve at z&lt;1.7. Synergy with observations from JWST and thirty meter class telescopes afford rich opportunities for advances throughout astrophysics.
Date: July 3, 2006
Creator: Aldering, Greg; Kim, Alex G.; Kowalski, Marek; Linder, Eric V. & Perlmutter, Saul
System: The UNT Digital Library
Sociodemographic characteristics and sexual behavior as risk factors for human papillomavirus infection in Saudi Arabia (open access)

Sociodemographic characteristics and sexual behavior as risk factors for human papillomavirus infection in Saudi Arabia

This article seeks to determine the prevalence and the sociodemographic characteristics and sexual behavior risk factors for human papillomavirus (HPV) infection in a hospital-based cohort of women in Saudi Arabia.
Date: April 3, 2016
Creator: Alhamlan, F. S.; Khayat, H. H.; Ramisetty-Mikler, Suhasini; Al-Muammar, T. A.; Tulbah, A. M.; Al-Badawi, I. A. et al.
System: The UNT Digital Library