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Thermal dissociation of SO₃ at 1000-1400 K

Description: Article on the thermal dissociation of SO3 at 1000 - 1400 K.
Date: January 12, 2006
Creator: Yilmaz, Ayten; Hindiyarti, Lusi; Jensen, Anker Degn; Glarborg, Peter & Marshall, Paul
Partner: UNT College of Arts and Sciences

The E-FAC: One Year Later

Description: This article discusses the Florida Administrative Register (FAR) and the Florida Administrative Code (FAC) one year after changes were made by the Florida Legislature.
Date: January 2015
Creator: Wondracek, Jennifer
Partner: UNT Dallas College of Law

1995 verification flow testing of the HDR reservoir at Fenton Hill, New Mexico

Description: Recent flow testing of the Fenton Hill HDR reservoir has demonstrated that engineered geothermal systems can be shut-in for extended periods of d= with apparently no adverse effects. However, when this particular reservoir at Venton Hill was shut-in for 2 years in a pressurized condition, natural convection within the open-jointed reservoir region appears to have leveled out the preexisting temperature gradient so that the gradient has now approached a condition more typical of liquid-dominated hydrothermal reservoirs which air invariably almost isothermal due to natural convection. As a result of the sudden flow impedance reduction that led to an almost 50% increase in Production flow new the end of the Second Phase of the LTFR in May 1993, we were uncertain as to the state of the reservoir after being shut-in for 2 years. The flow performance observed during the current testing was found to be intermediate between that at-the end of the Second Phase of the LTFT and that following, the subsequent sudden flow increase, implying that whatever caused the sudden reduction in impedance in the first place is probably somehow associated with the cooldown of the reservoir near the injection interval, since temperature recovery at the surfaces of the surrounding open joints is the most obvious phenomenon expected to occur over time within the reservoir.
Date: January 1, 1995
Creator: Brown, D.
Partner: UNT Libraries Government Documents Department

The impact of repository heat on hydrological behavior at Yucca Mountain

Description: This report describes the role of radioactive heat-of-decay in the the performance of the Yucca Mountain Facility. Waste package and waste form degradation due to water contact is described.
Date: January 1, 1994
Creator: Buscheck, T.A. & Nitao, J.J.
Partner: UNT Libraries Government Documents Department

Preliminary drift design analyses for nuclear waste repository in tuff

Description: The Yucca Mountain Project (YMP) is examining the feasibility of siting a repository for high-level nuclear waste at Yucca Mountain, on and adjacent to the Nevada Test Site (NTS). The proposed repository will be excavated in the Topopah Spring Member, which is a moderately fractured, unsaturated, welded tuff. Excavation stability will be required during construction, waste emplacement, retrieval (if required), and closure to ensure worker safety. The subsurface excavations will be subject to stress changes resulting from thermal expansion of the rock mass and seismic events associated with regional tectonic activity and underground nuclear explosions (UNEs). Analyses of drift stability are required to assess the acceptable waste emplacement density, to design the drift shapes and ground support systems, and to establish schedules and cost of construction. This paper outlines the proposed methodology to assess drift stability and then focuses on an example of its application to the YMP repository drifts based on preliminary site data. Because site characterization activities have not begun, the database currently lacks the extensive site-specific field and laboratory data needed to form conclusions as to the final ground support requirements. This drift design methodology will be applied and refined as more site-specific data are generated and as analytical techniques and methodologies are verified during the site characterization process.
Date: January 30, 1990
Creator: Hardy, M.P.; Brechtel, C.E.; Goodrich, R.R. & Bauer, S.J.
Partner: UNT Libraries Government Documents Department

Estimating the effects of air pollution on buildings and structures: The US experience since 1985 and some lessons for the future

Description: Damage to the built environment has always been the foster child of the environmental movement in the United States. Although the Clean Air Act includes damage to materials as one of the welfare effects to be considered when setting secondary air quality standards, the main activity by the U.S. Environmental Protection Agency (EPA) in this discipline seems to be the periodic review of literature required to assemble the official documents needed to review these standards. The one important exception was the National Acid Precipitation Assessment Program (NAPAP), which included a materials damage research activity amounting to a few percent of its total $500 million budget. The 1990 NAPAP State of Science and Technology Report includes three of its twenty-seven chapters on this topic, in addition to portions of the chapter on economic valuation methods. The 1990 NAPAP Integrated Assessment Report debated the economic importance of damage to galvanized steel and to carbonate stone buildings, discussed confounding and mitigating factors for damage to paints, and listed some priorities for assessment of damage to cultural resources. However, in contrast to NAPAP`s views, one independent assessment was that {open_quotes}The NAPAP study found that, at current levels, the major negative effects of acid deposition are probably reduced visibility and accelerated deterioration of outdoor cultural resources{close_quotes}. Since the 1990 reports and the passage of the 1990 Clean Air Act Amendments, NAPAP has contracted to a fraction of its former size. NAPAP now produces a biennial Report to Congress; release of the 1994 report is reported to be imminent. This paper will attempt to review what was accomplished by NAPAP with respect to economic assessment of materials damage and the supporting research and will then go on to postulate some guidelines for future assessments.
Date: January 1, 1996
Creator: Lipfert, F.W.
Partner: UNT Libraries Government Documents Department

A coaxial ring-sidearm power extraction design

Description: We report a successful klystron power extraction design, in which a TEM coaxial mode is transmitted into TE10 mode of a WR90 rectangular waveguide at 11.42 GHz, with very little TEM reflection and almost vanishing asymmetric (TEM {r_arrow} TE11, or monopole to dipole) reflectance. Our coupler consists of a ring (disk) around the coaxial waveguide, and a coax-WR90 sidearm junction. The methods used in the design are numerical simulation, performed on the MAFIA3 T3 time- domain module and on the High Frequency Structure Simulator, and analytical treatment to guide the numerical runs. The demerit parameters (dipole reflectance and TEM reflection) can be reduced as much as desired (to zero in principle), the only limitation being computer run time and memory. Results are accurate to a few percent.
Date: January 1, 1996
Creator: Ben-Menahem, S. & Yu, D.
Partner: UNT Libraries Government Documents Department

Surface state and normal layer effects in high T{sub c} superconductors

Description: In addition to the conducting CuO{sub 2} (S) layers, most high-{Tc}, superconductors also contain other conducting (N) layers, which are only superconducting due to the proximity effect. The combination of S and N layers can give rise to complicated electronic densities of states, leading to quasilinear penetration depth and NMR relaxation rate behavior at low temperatures. Surface states can also complicate the analysis of tunneling and photoemission measurements. Moreover, geometrical considerations and inhomogeneously trapped flux are possible explanations of the paramagnetic Meissner effect and of corner and ring SQUID experiments. Hence, all of the above experiments could be consistent with isotropic s-wave superconductive within the S layers.
Date: January 1, 1996
Creator: Klemm, R.A.; Ledvij, M. & Liu, Samuel H.
Partner: UNT Libraries Government Documents Department

Magnetic-Field-Induced V-Shaped Quantized Conductance Staircase in a Double-Layer Quantum Point Contact

Description: We show that the low-temperature conductance (G) of a quantum point contact consisting of ballistic tunnel-coupled double-layer quantum well wires is modulated by an in-layer magnetic field B{sub {parallel}} perpendicular to the wires due to the anticrossing. In a system with a small g factor, B{sub {parallel}} creates a V-shaped quantum staircase for G, causing it to decrease in steps of 2e{sup 2}/{Dirac_h} to a minimum and then increase to a maximum value, where G may saturate or decrease again at higher B{sub {parallel}}'s. The effect of B{sub {parallel}}-induced mass enhancement and spin splitting is studied. The relevance of the results to recent data is discussed.
Date: January 4, 1999
Creator: Lyo, S.K.
Partner: UNT Libraries Government Documents Department

Application of the FD-TD method to the electromagnetic modeling of patch antenna arrays

Description: FD-TD method and the Berenger Perfectly Matched Layer (PML) absorbing condition are applied to the modeling of a 32-element patch array. Numerical results for the return loss at the array feed are presented and compared to measured results for the purpose of model validation.
Date: January 10, 1996
Creator: Pasik, M.F.; Aguirre, G. & Cangellaris, A.C.
Partner: UNT Libraries Government Documents Department