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De-coupling of exchange and persistence times in atomistic modelsof glass formers

Description: With molecular dynamics simulations of a fluid mixture of classical particles interacting with pair-wise additive Weeks-Chandler-Andersen potentials, we consider the time series of particle displacements and thereby determine distributions for local persistence times and local exchange times. These basic characterizations of glassy dynamics are studied over a range of super-cooled conditions and shown to have behaviors, most notably de-coupling, similar to those found in kinetically constrained lattice models of structural glasses. Implications are noted.
Date: August 15, 2007
Creator: Hedges, Lester O.; Maibaum, Lutz; Chandler, David & Garrahan, Juan P.
Partner: UNT Libraries Government Documents Department

Loss of xylidines in overwater storage of xylidine-blended fuel

Description: Tests were undertaken to determine the relationships for estimating the maximum amount of a water-soluble gasoline additive that will diffuse from the gasoline to the water when fuel is stored over the water and to determine from the relationships the amount of xylidines that will diffuse from the gasoline to the water in an overwater-storage system.
Date: March 1944
Creator: Tischler, Adelbert O. & Tischler, Adelbert O.
Partner: UNT Libraries Government Documents Department

Effects of additives on pressure limits of flame propagation of propane-air mixtures

Description: Report presenting a study of seven additives in 0.5-volume-percent concentration for their effects on the low-pressure limits of flame propagation of propane-air mixtures. Limits were measured in a flame tube of new design. Results regarding propane-air mixtures, propane-air-additive mixtures, and flame propagation qualities are provided.
Date: December 18, 1953
Creator: Belles, Frank E. & Simon, Dorothy M.
Partner: UNT Libraries Government Documents Department

Ignition of Ammonia and Mixed Oxides of Nitrogen in 200-Pound-Thrust Rocket Engines at 160 Degrees F

Description: Memorandum presenting a study of the ignition of ammonia and mixed oxides of nitrogen at 160 degrees Fahrenheit made with and without fuel additives utilizing small-scale rocket engines of approximately 200 pounds thrust. All experiments were conducted at sea-level pressures except two at a range of pressure altitudes. Results regarding the use of lithium as a catalyst, calcium as a catalyst, and no apparent catalyst are provided.
Date: May 13, 1954
Creator: Hennings, Glen; Ladanyi, Dezso J. & Enders, John H.
Partner: UNT Libraries Government Documents Department

Static Crucible Investigation of Corrosion and Mass-Transfer of Nickel in Molten Sodium Hydroxide With Various Additives

Description: Memorandum presenting an investigation of the effects of a number of additives on the phenomena of corrosion and mass transfer of nickel by molten sodium hydroxide in the neighborhood of 1500 degrees Fahrenheit by means of static crucible tests. The additives are classified by their effects, including being detrimental, inert, and beneficial. The additives found to reduce mass transfer were calcium hydride, sodium aluminate, and hydrogen.
Date: August 1953
Creator: Forestieri, Americo F. & Zelezny, William F.
Partner: UNT Libraries Government Documents Department

Correlation Between Hydrogen Pressure and Protective Action of Additives in the Molten Sodium Hydroxide - Nickel System

Description: Memorandum presenting an investigation of the effect of various metallic additives on the molten sodium hydroxide - nickel system. The hydrogen evolved from such systems was measured and the evolution was correlated with the effect of the metal on mass transfer. Results regarding a check with standard tests, purging, presence of two valences for chromium, reaction time of the additive, and pressure within nickel crucibles are provided.
Date: February 9, 1956
Creator: May, Charles E.
Partner: UNT Libraries Government Documents Department

Phosphazene Based Additives for Improvement of Safety and Battery Lifetimes in Lithium-Ion Batteries

Description: There need to be significant improvements made in lithium-ion battery technology, principally in the areas of safety and useful lifetimes to truly enable widespread adoption of large format batteries for the electrification of the light transportation fleet. In order to effect the transition to lithium ion technology in a timely fashion, one promising next step is through improvements to the electrolyte in the form of novel additives that simultaneously improve safety and useful lifetimes without impairing performance characteristics over wide temperature and cycle duty ranges. Recent efforts in our laboratory have been focused on the development of such additives with all the requisite properties enumerated above. We present the results of the study of novel phosphazene based electrolytes additives.
Date: October 1, 2011
Creator: Harrup, Mason K; Gering, Kevin L; Rollins, Harry W; Sazhin, Sergiy V; Benson, Michael T; Jamison, David K et al.
Partner: UNT Libraries Government Documents Department

Temperature response of turbine-blade metal covered with oxide coatings supplied by fuel additives

Description: Report presenting an investigation to determine the effects of turbine-blade coatings, supplied by fuel additives, on heat transfer with combustor exhaust gases to an S-816 alloy blade. Two fuel additives were used. The results indicated that the fuel additives provided an oxide coating on the combustor-liner wall and other metal parts, including the blade, exposed to the exhaust gas.
Date: August 20, 1952
Creator: McCafferty, Richard J. & Butze, Helmut F.
Partner: UNT Libraries Government Documents Department

Effect of chemical reactivity of lubricant additives on friction and surface welding at high sliding velocities

Description: Report presenting an investigation of the effect of chemical reactivity of lubricant additives on friction at high sliding velocities. The investigation was conducted with a kinetic-friction apparatus consisting of an elastically restrained spherical rider specimen sliding on a rotating steel disk lubricated with cetane containing lubricant additives of different chemical reactivities. Results regarding chlorine compounds and sulfur compounds are provided.
Date: August 1950
Creator: Bisson, Edmond E.; Swikert, Max A. & Johnson, Robert L.
Partner: UNT Libraries Government Documents Department

Reactions with steel of compounds containing chemical groups used in lubricant additives

Description: Report presenting an investigation of the chemical reactions between steel of a type used in aircraft-engine cylinder barrels and compounds containing reactive groups commonly found in lubricant additives. The products formed by reaction at temperatures from 400 to 650 degrees F were analyzed by reflection electron diffraction. Results regarding the diffraction patterns, a description of the products found, and correlation of the results with results form other investigations are provided.
Date: February 1947
Creator: Powell, Allen S.
Partner: UNT Libraries Government Documents Department

Effects of Additives on Corrosion and Mass Transfer in Sodium Hydroxide - Nickel Systems Under Free-Convection Conditions

Description: Memorandum presenting a study of the effect of additives on the extent of corrosion and mass transfer in sodium hydroxide - "L" nickel systems. The extent of corrosion and mass transfer was determined by a measurement of the weight change of a specimen in the hot zone, and by metallographic examination of the specimen cross section. Results regarding the reproducibility, appearance of specimens, and additives having a detrimental effect, no effect, or a beneficial effect are provided.
Date: August 2, 1954
Creator: Forestieri, Americo F.
Partner: UNT Libraries Government Documents Department

An infinite branching hierarchy of time-periodic solutions of the Benjamin-Ono equation

Description: We present a new representation of solutions of the Benjamin-Ono equation that are periodic in space and time. Up to an additive constant and a Galilean transformation, each of these solutions is a previously known, multi-periodic solution; however, the new representation unifies the subset of such solutions with a fixed spatial period and a continuously varying temporal period into a single network of smooth manifolds connected together by an infinite hierarchy of bifurcations. Our representation explicitly describes the evolution of the Fourier modes of the solution as well as the particle trajectories in a meromorphic representation of these solutions; therefore, we have also solved the problem of finding periodic solutions of the ordinary differential equation governing these particles, including a description of a bifurcation mechanism for adding or removing particles without destroying periodicity. We illustrate the types of bifurcation that occur with several examples, including degenerate bifurcations not predicted by linearization about traveling waves.
Date: July 1, 2008
Creator: Wilkening, Jon
Partner: UNT Libraries Government Documents Department

MODIFIED BOROHYDRIDES FOR REVERSIBLE HYDROGEN STORAGE

Description: This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing dehydriding temperature and generating dehydriding-rehydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature.
Date: May 10, 2006
Creator: Au, Ming
Partner: UNT Libraries Government Documents Department

A nonlocal, ordinary, state-based plasticity model for peridynamics.

Description: An implicit time integration algorithm for a non-local, state-based, peridynamics plasticity model is developed. The flow rule was proposed in [3] without an integration strategy or yield criterion. This report addresses both of these issues and thus establishes the first ordinary, state-based peridynamics plasticity model. Integration of the flow rule follows along the lines of the classical theories of rate independent J{sub 2} plasticity. It uses elastic force state relations, an additive decomposition of the deformation state, an elastic force state domain, a flow rule, loading/un-loading conditions, and a consistency condition. Just as in local theories of plasticity (LTP), state variables are required. It is shown that the resulting constitutive model does not violate the 2nd law of thermodynamics. The report also develops a useful non-local yield criterion that depends upon the yield stress and horizon for the material. The modulus state for both the ordinary elastic material and aforementioned plasticity model is also developed and presented.
Date: May 1, 2011
Creator: Mitchell, John Anthony
Partner: UNT Libraries Government Documents Department

Stack filter classifiers

Description: Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.
Date: January 1, 2009
Creator: Porter, Reid B & Hush, Don
Partner: UNT Libraries Government Documents Department

Tailoring the intergranular phases in silicon nitride for improved toughness

Description: Intergranular glass phases can have a significant influence on fracture resistance (R-curve behavior) of Si nitride ceramics and appears to be related to debonding of the {beta}-Si{sub 3}N{sub 4}/oxynitride-glass interfaces. Applying the results from {beta}- Si{sub 3}N{sub 4}-whisker/oxynitride-glass model systems, self- reinforced Si nitrides with different sintering additive ratios were investigated. Si nitrides sintered with a lower Al{sub 2}O{sub 3}: Y{sub 2}O{sub 3} additive ratio exhibited higher stead-state fracture toughness together with a steeply rising R-curve. Analytical electron microscopy suggested that the different fracture behavior is related to the Al content in the SiAlON growth band on the elongated grains, which could result in differences in interfacial bonding structures between the grains and the intergranular glass.
Date: December 31, 1996
Creator: Sun, E. Y.; Becher, P. F.; Plucknett, K. P.; Waters, S. B.; Hirao, K. & Brito, M. E.
Partner: UNT Libraries Government Documents Department

Test report - caustic addition system operability test procedure

Description: This Operability Test Report documents the test results of test procedure WHC-SD-WM-OTP-167 ``Caustic Addition System Operability Test Procedure``. The Objective of the test was to verify the operability of the 241-AN-107 Caustic Addition System. The objective of the test was met
Date: October 13, 1995
Creator: Parazin, R.E.
Partner: UNT Libraries Government Documents Department

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS

Description: This first semiannual report covers efforts to select the materials that will be used in this project. Discussions of crude oils, rocks, smooth mineral surfaces, and drilling mud additives are included in this report.
Date: June 1, 2002
Creator: Buckley, Jill S. & Morrow, Norman r.
Partner: UNT Libraries Government Documents Department

Metallic fuels: The EBR-II legacy and recent advances

Description: Experimental Breeder Reactor – II (EBR-II) metallic fuel was qualified for high burnup to approximately 10 atomic per cent. Subsequently, the electrometallurgical treatment of this fuel was demonstrated. Advanced metallic fuels are now investigated for increased performance, including ultra-high burnup and actinide burning. Advances include additives to mitigate the fuel/cladding chemical interaction and uranium alloys that combine Mo, Ti and Zr to improve alloy performance. The impacts of the advances—on fabrication, waste streams, electrorefining, etc.—are found to be minimal and beneficial. Owing to extensive research literature and computational methods, only a modest effort is required to complete their development.
Date: September 1, 2012
Creator: Porter, Douglas L.; Hayes, Steven L. & Kennedy, J. Rory
Partner: UNT Libraries Government Documents Department

Enzymology of acetone-butanol-isopropanol formation. Final technical report, June 1, 1985--July 31, 1997

Description: Several species of anaerobic bacteria within the genus Clostridium produce acetone, n-butanol, and isopropanol (solvents), which are important industrial chemicals and fuel additives. Commercial production of solvents by the clostridia is a classical example of largescale chemical production by bacterial fermentation. Although the fermentation has been in use for decades, it still faces problems that include strain degeneration, a relatively low final product concentration due to butanol toxicity, and a need to fine-tune the growth conditions to achieve a high yield. The long-term goal of this project was to understand the fundamental properties of bacterial solvent production for the purpose of achieving a positive control on the metabolic switch leading to solvent production and on the proportion of useful products formed as well as of developing strategies for preventing the degeneration of producing strains. The objectives for the project included those approved in 1985 for the initial project period and those approved in 1988, 1991, and 1994 when the project was renewed. The objectives for the entire project period may be summarized as (1) To purify and characterize the enzymes that are specifically required for the formation of acetone, butanol, and isopropanol by the clostridia, (2) To clone and characterize the genes that encode enzymes or regulatory proteins for the production of solvents, and the emphasis was to determine the control mechanism for the transcription of the solvent-production genes, (3) To characterize the onset of solvent production and the intra- and extra-cellular parameters surrounding the metabolic switch to solvent production, and (4) To determine the genetic identity of the strains of solvent-producing clostridia that are currently in use by investigators around the world.
Date: March 1, 1998
Creator: Chen, Jiann-Shin
Partner: UNT Libraries Government Documents Department

Detailed chemical kinetic modeling of diesel combustion with oxygenated fuels

Description: The influence of oxygenated hydrocarbons as additives to diesel fuels on ignition, NOx emissions and soot production has been examined using a detailed chemical kinetic reaction mechanism. N-heptane was used as a representative diesel fuel, and methanol, ethanol, dimethyl ether and dimethoxymethane were used as oxygenated fuel additives. It was found that addition of oxygenated hydrocarbons reduced NOx levels and reduced the production of soot precursors. When the overall oxygen content in the fuel reached approximately 25% by mass, production of soot precursors fell effectively to zero, in agreement with experimental studies. The kinetic factors responsible for these observations are discussed.
Date: October 28, 1999
Creator: Pitz, W J; Curran, H J; Fisher, E; Glaude, P A; Marinov, N M & Westbrook, C K
Partner: UNT Libraries Government Documents Department