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Effect of pressure quenching on the structures and properties of borosilicate glasses: Insights from molecular dynamics simulations

Description: Article describes how processes including hot compression, cold compression and subsequent annealing on the structures and properties are investigated and compared. They found that applying pressure up to 10 GPa at the glass transition temperature led to permanent densifications and a dramatic increase of elastic moduli by 90%, while thermal annealing reversed the increase and applying pressure at ambient temperature did not increase the modulus.
Date: August 23, 2022
Creator: Ren, Mengguo & Du, Jincheng
Partner: UNT College of Engineering
open access

Acetaldehyde oxidation at elevated pressure

Description: A detailed chemical kinetic model for oxidation of CH3CHO at intermediate to high temperature and elevated pressure has been developed and evaluated by comparing predictions to novel high-pressure flow reactor experiments as well as shock tube ignition delay measurements and jet-stirred reactor data from literature. The flow reactor experiments were conducted with a slightly lean CH3CHO/O2 mixture highly diluted in N2 at 600–900 K and pressures of 25 and 100 bar. This is the accepted manuscript… more
Date: April 10, 2021
Creator: Hashemi, Hamid; Christensen, Jakob M.; Marshall, Paul & Glarborg, Peter
Partner: UNT College of Science
open access

Dynamic Shear Deformation of a Precipitation Hardened Al0.7CoCrFeNi Eutectic High-Entropy Alloy Using Hat-Shaped Specimen Geometry

Description: The article reports on the shear deformation of a eutectic structured HEA and effect of precipitation on shear deformation, particularly Al₀.₇CoCrFeNi high-entropy alloy (HEA). A split-Hopkinson pressure bar (SHPB) was used to compress the hat-shaped specimens to study the local dynamic shear response of the alloy. The change in the width of shear bands with respect to precipitation and deformation rates was studied. The precipitation of L1₂ phase did not delay the formation of adiabatic shear… more
Date: April 10, 2020
Creator: Gwalani, Bharat; Wang, Tianhao; Jagetia, Abhinav; Gangireddy, Sindhura; Muskeri, Saideep; Mukherjee, Sundeep et al.
Partner: UNT College of Engineering
open access

Hydrostatic High-Pressure Post-Processing of Specimens Fabricated by DLP, SLA, and FDM: An Alternative for the Sterilization of Polymer-Based Biomedical Devices

Description: This article assesses the effects of sterilization in materials manufactured using additive manufacturing by employing a sterilization technique used in the food industry.
Date: December 13, 2018
Creator: Robles Linares-Alvelais, José; Figueroa-Cavazos, J. Obedt; Chuck-Hernandez, C.; Siller Carrillo, Héctor Rafael; Rodríguez, Ciro A. & Martínez-López, J. Israel
Partner: UNT College of Engineering
open access

The C₂H₂ + NO₂ Reaction: Implications for High Pressure Oxidation of C₂H₂/NOx Mixtures

Description: Article discussing an experimental and kinetic modeling study of the interaction between C₂H₂ and NOx under flow reactor conditions in the intermediate temperature range (600–900 K), high pressure (50–60 bar), and for stoichiometries ranging from reducing to strongly oxidizing. The results show that presence of NOx serves both to sensitize and inhibit oxidation of C₂H₂.
Date: July 25, 2018
Creator: Marshall, Paul; Leung, Caroline; Lopez, Jorge Gimenez; Rasmussen, Christian T.; Hashemi, Hamid; Glarborg, Peter et al.
Partner: UNT College of Science
open access

An Exploratory Flow Reactor Study of Hydrogen Sulfide Oxidation at 30–100 Bar

Description: Article exploring experiments on hydrogen sulfide oxidation that were conducted in O₂/N₂ at high pressure (30 and 100 bar) under oxidizing and stoichiometric conditions.
Date: November 9, 2016
Creator: Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt; Zou, Chun; Haynes, Brian S.; Marshall, Paul et al.
Partner: UNT College of Arts and Sciences
open access

Electrical properties of SnSe under high-pressure

Description: This article investigates the pressure-induced phase transitions in SnSe using the first-principles density functional calculations.
Date: November 3, 2016
Creator: Ghosh, Angsula; Gusmão, M. S.; Chaudhuri, Puspitapallab; de Souza, S. Michielon; Mota, Cicero; Trichês, D. M. et al.
Partner: UNT College of Arts and Sciences
open access

Electrical Properties of Tin Selenide Under High-Pressure

Description: The article investigates the pressure-induced phase transitions in tin selenide (SnSe). using the first-principles density functional calculations. The experimental results in the nanostructured SnSe revealed a phase transition at 4 GPa whereas that in the well-crystallized samples showed at 10 GPa.
Date: November 3, 2016
Creator: Ghosh, Angsula; Gusmão, M. S.; Chaudhuri, Puspitapallab; de Souza, S. Michielon; Mota, Cicero; Trichês, D. M. et al.
Partner: UNT College of Arts and Sciences
open access

Experimental and Kinetic Modeling Study of Acetylene Oxidation at High Pressure

Description: Article describing a detailed chemical kinetic model for oxidation of acetylene at intermediate temperatures and high pressure that was developed and evaluated experimentally.
Date: August 29, 2016
Creator: Lopez, Jorge Gimenez; Rasmussen, Christian Lund; Hashemi, Hamid; Alzueta, María U.; Gao, Yide; Marshall, Paul et al.
Partner: UNT College of Arts and Sciences
open access

Ammonia Oxidation at High Pressure and Intermediate Temperatures

Description: This article describes ammonia oxidation experiments conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K.
Date: May 10, 2016
Creator: Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt; Zou, Chun; Marshall, Paul & Glarborg, Peter
Partner: UNT College of Arts and Sciences
open access

Effect of surfactants on pressure-sensitivity of carbon nanotube filled cement mortar composites

Description: In this article, the pressure-sensitivity of CNT filled cement mortar composites with different concentrations of MWNT and different surfactants is investigated under repeated loading and impulsive loading, respectively. Experimental results indicate that the response of the electrical resistance of composites with NaDDBS to external force is more stable and sensitive than that of composites with SDS. Therefore, NaDDBS has higher efficiency than SDS for the dispersion of MWNT in cement mortar, … more
Date: November 6, 2014
Creator: Han, Baoguo & Yu, Xun
Partner: UNT College of Engineering
open access

Modeling the Ductile Brittle Fracture Transition in Reactor Pressure Vessel Steels using a Cohesive Zone Model based approach

Description: Fracture properties of Reactor Pressure Vessel (RPV) steels show large variations with changes in temperature and irradiation levels. Brittle behavior is observed at lower temperatures and/or higher irradiation levels whereas ductile mode of failure is predominant at higher temperatures and/or lower irradiation levels. In addition to such temperature and radiation dependent fracture behavior, significant scatter in fracture toughness has also been observed. As a consequence of such variability … more
Date: October 1, 2013
Creator: Chakraborty, Pritam & Biner, S. Bulent
Partner: UNT Libraries Government Documents Department
open access

Direct-Steam Linear Fresnel Performance Model for NREL's System Advisor Model

Description: This paper presents the technical formulation and demonstrated model performance results of a new direct-steam-generation (DSG) model in NREL's System Advisor Model (SAM). The model predicts the annual electricity production of a wide range of system configurations within the DSG Linear Fresnel technology by modeling hourly performance of the plant in detail. The quasi-steady-state formulation allows users to investigate energy and mass flows, operating temperatures, and pressure drops for geom… more
Date: September 1, 2012
Creator: Wagner, M. J. & Zhu, G.
Partner: UNT Libraries Government Documents Department
open access

High-temperature treatment of In-doped CZT crystals grown by the high-pressure Bridgman method

Description: We evaluated the effect of high-temperature treatment of Cd0.9Zn0.1Te:In single crystals using Hall-effect measurements, medium- and high-temperature annealing under various deviations from stoichiometry, and infra-red (IR) transmission microscopy Annealing at ~730 K sharply increased the electrical conductivity (by ~1-2 orders-of-magnitude). Plots of the temperature- and cadmium-pressure dependences of the electrical conductivity, carrier concentration, and mobility were obtained. Treating pre… more
Date: August 12, 2012
Creator: Bolotnikov, A.; Fochuk, P.; Nakonechnyi, I.; Kopach, O.; Verzhak, Ye.; Panchuk, O. et al.
Partner: UNT Libraries Government Documents Department
open access

APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS

Description: This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to… more
Date: July 11, 2012
Creator: Blanton, P.; Eberl, K. & Abramczyk, G.
Partner: UNT Libraries Government Documents Department
open access

The First ASME Code Stamped Cryomodule at SNS

Description: The first spare cryomodule for the Spallation Neutron Source (SNS) has been designed, fabricated, and tested by SNS personnel. The approach to design for this cryomodule was to hold critical design features identical to the original design such as bayonet positions, coupler positions, cold mass assembly, and overall footprint. However, this is the first SNS cryomodule that meets the pressure requirements put forth in the 10 CFR 851: Worker Safety and Health Program. The most significant differe… more
Date: July 1, 2012
Creator: Howell, M. P.; Crofford, M. T.; Douglas, D. L.; Kim, S. H.; Steward, S. T.; Strong, W. H. et al.
Partner: UNT Libraries Government Documents Department
open access

Large-Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell SRF Cavity

Description: We report the preliminary results on plasma generation in a 5-cell CEBAF superconducting radio-frequency (SRF) cavity for the application of cavity interior surface cleaning. CEBAF currently has {approx}300 of these five cell cavities installed in the Jefferson Lab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant CEBAF accelerator performance impro… more
Date: July 1, 2012
Creator: J. Mammosser, S. Ahmed, K. Macha, J. Upadhyay, M. Nikoli, S. Popovi, L. Vuakovi
Partner: UNT Libraries Government Documents Department
open access

METAL MEDIA FILTERS, AG-1 SECTION FI

Description: One application of metal media filters is in various nuclear air cleaning processes including applications for protecting workers, the public and the environment from hazardous and radioactive particles. To support this application the development of the ASME AG-1 FI Standard on Metal Media has been under way for more than ten years. Development of the proposed section has required resolving several difficult issues associated with operating conditions (media velocity, pressure drop, etc.), qua… more
Date: May 23, 2012
Creator: Adamson, D.
Partner: UNT Libraries Government Documents Department
open access

Duplex Oxide Formation during Transient Oxidation of Cu-5%Ni(001) Investigated by In situ UHV-TEM and XPS

Description: The transient oxidation stage of a model metal alloy thin film was characterized with in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and analytic high-resolution TEM. We observed the formations of nanosized NiO and Cu{sub 2}O islands when Cu-5a5%Ni(100) was exposed to oxygen partial pressure, pO{sub 2} = 1 x 10{sup -4} Torr and various temperatures in situ. At 350 C epitaxial Cu{sub 2}O islands formed initially and then NiO islands… more
Date: May 20, 2012
Creator: Yang, J.C.; Starr, D.; Kang, Y.; Luo, L.; Tong, X. & Zhou, G.
Partner: UNT Libraries Government Documents Department
open access

Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment

Description: The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels devel… more
Date: May 6, 2012
Creator: Ziomek-Moroz, M.; Hawk, J. A.; Ramgopal, Thodla & Gui, F.
Partner: UNT Libraries Government Documents Department
open access

CONTAINMENT OF LOW-LEVEL RADIOACTIVE WASTE AT THE DOE SALTSTONE DISPOSAL FACILITY

Description: As facilities look for permanent storage of toxic materials, they are forced to address the long-term impacts to the environment as well as any individuals living in affected area. As these materials are stored underground, modeling of the contaminant transport through the ground is an essential part of the evaluation. The contaminant transport model must address the long-term degradation of the containment system as well as any movement of the contaminant through the soil and into the groundwa… more
Date: March 29, 2012
Creator: Jordan, J. & Flach, G.
Partner: UNT Libraries Government Documents Department
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