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Effect of equivalence ratio on premixed flame response to unsteady strain-rate and curvature

Effect of equivalence ratio on premixed flame response to unsteady strain-rate and curvature

Date: March 1, 1998
Creator: Najm, H.N.; Wyckoff, P.S. & Knio, O.M.
Description: The interaction of a premixed stoichiometric methane-air flame with a two-dimensional counter-rotating vortex pair is studied under stoichiometric and rich conditions using a detailed C{sub 1}C{sub 2} chemical mechanism. The focus is on the effect of equivalence ratio on flame response to unsteady strain-rate and curvature. Flame structure and transient response are studied, both at curved cusps and on the vortex-pair centerline. The rich flame is found to exhibit faster response to flow disturbances. Results suggest this is due to the increased sensitivity of the flame to H concentration at rich conditions. Significant differences are observed in the unsteady behavior of some C{sub 2} species, where substantial transient accumulation is observed at stoichiometric conditions, but not at rich conditions. Transient response of flame observables, such as CH, OH, and HCO, is studied and compared to experimental data.
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Estradiol-17(beta), Goitrogen (T3), and Flutamide on Gene Expression in Medaka, Oryzias latipes

The Effect of Estradiol-17(beta), Goitrogen (T3), and Flutamide on Gene Expression in Medaka, Oryzias latipes

Date: September 6, 2005
Creator: E.Haut, J
Description: Concern has been generated over the discovery of endocrine disrupting chemicals in rivers near sewage outflows. The presence of endocrine disrupting chemicals such as estradiol-17{beta} has been associated with a reduction of reproductive success in fish and an increase in the female phenotype and gonadal intersex in fish downstream of sewage treatment facilities. Such effects are believed to result from a disruption in the normal estrogenic pathways since estrogen plays a vital role in reproduction, sexual differentiation, the developments of secondary sex characteristics, and ovulation. Most studies have focused on the effect of a single endocrine disruptor on a single gene which does not provide for the interaction between genes. Microarray technology has made it possible to put an entire genome on a single chip so that researchers can get a clearer picture of the interaction of genes expressed in a cell and changes of said interactions when those cells are exposed to various conditions. Medaka males were exposed to known endocrine disruptors, estradial-17{beta} and goitrogen, and medaka females were exposed to flutamide. All treatments were then compared to controls. Total RNA was extracted from the livers of both treated and untreated males and hybridized to a microarray chip designed ...
Contributing Partner: UNT Libraries Government Documents Department
Effect of ethanol fuel additive on diesel emissions.

Effect of ethanol fuel additive on diesel emissions.

Date: September 11, 2001
Creator: Cole, R. L.; Poola, R. B.; Sekar, R.; Schaus, J. E. & McPartlin, P.
Description: Engine-out emissions from a Volkswagen model TDI engine were measured for three different fuels: neat diesel fuel, a blend of diesel fuel and additives containing 10% ethanol, and a blend of diesel fuel and additives containing 15% ethanol. The test matrix covered five speeds from 1,320 to 3,000 rpm, five torques from 15 Nm to maximum plus the 900-rpm idle condition, and most of the points in the FTP-75 and US-06 vehicle tests. Emissions of particulate matter (PM), nitrogen oxides (NO{sub x}), unburned hydrocarbons (HCs), and carbon monoxide (CO) were measured at each point, as were fuel consumption, exhaust oxygen, and carbon dioxide output. PM emissions were reduced up to 75% when ethanol-diesel blends were used instead of neat diesel fuel. Significant reductions in PM emissions occurred over one-half to two-thirds of the test matrix. NO{sub x} emissions were reduced by up to 84%. Although the regions of reduced NO{sub x} emissions were much smaller than the regions of reduced PM emissions, there was considerable overlap between the two regions where PM emissions were reduced by up to 75% and NO{sub x} emissions were reduced by up to 84%. Such simultaneous reduction of both PM and NO{sub x} emissions would ...
Contributing Partner: UNT Libraries Government Documents Department
The effect of ethylene dibromide on the knock-limited performance of leaded and nonleaded S reference fuel

The effect of ethylene dibromide on the knock-limited performance of leaded and nonleaded S reference fuel

Date: February 1, 1946
Creator: Niemi, Richard O
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Excess Carbon on the Crystallographic, Microstructural, and Mechanical Properties of CVD Silicon Carbide Fibers

The Effect of Excess Carbon on the Crystallographic, Microstructural, and Mechanical Properties of CVD Silicon Carbide Fibers

Date: December 5, 2006
Creator: Marzik, J V; Croft, W J; Staples, R J & MoberlyChan, W J
Description: Silicon carbide (SiC) fibers made by chemical vapor deposition (CVD) are of interest for organic, ceramic, and metal matrix composite materials due their high strength, high elastic modulus, and retention of mechanical properties at elevated processing and operating temperatures. The properties of SCS-6{trademark} silicon carbide fibers, which are made by a commercial process and consist largely of stoichiometric SiC, were compared with an experimental carbon-rich CVD SiC fiber, to which excess carbon was added during the CVD process. The concentration, homogeneity, and distribution of carbon were measured using energy dispersive x-ray spectroscopy (SEM/EDS). The effect of excess carbon on the tensile strength, elastic modulus, and the crystallographic and microstructural properties of CVD silicon carbide fibers was investigated using tensile testing, x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Excimer Laser Treatment on the Surface Roughness and Fracture Strength of Alumina Substrates

The Effect of Excimer Laser Treatment on the Surface Roughness and Fracture Strength of Alumina Substrates

Date: May 13, 1998
Creator: Smoot, J. E.
Description: The microelectronics industry requires alumina substrates with exceptionally smooth surfaces and few surface defects to allow successful deposition of metallic films for reliable electronic performance. Irradiation by a 248-nm wavelength excimer laser beam (KrF) at a fluence of 125 mJ/mm{sup 2} and at various angles of incidence is shown to significantly reduce the surface roughness of alumina substrates. However, irradiation also creates a fine particulate deposit of alumina that only partially adheres to the substrate and impedes deposition of metal films. Annealing in air between 1350 C and 1450 C was found to remove the particles by sintering. As-received material showed surface roughness average (R{sub a}) mean values of 457 nm, which was reduced to 60 nm (mean) following irradiation and 71 nm (mean) following irradiation and annealing at 1350 C. Irradiation also produced a decrease in the number and severity of surface defects. The flexural strength and Weibull modulus were both increased by laser irradiation and thermal treatment. Flexural strength went from an as-received value of 450 MPa to 560 MPa following irradiation/sintering, measured at 10% probability of failure. The Weibull modulus was increased from the as-received value of about 9, to about 13 following irradiation/sintering. It was concluded ...
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust back pressure on engine power

Effect of exhaust back pressure on engine power

Date: June 1, 1943
Creator: Pinkel, Benjamin
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust-nozzle ejectors on turbojet noise generation

Effect of exhaust-nozzle ejectors on turbojet noise generation

Date: October 1, 1955
Creator: North, Warren J & Coles, Willard D
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust pressure on knock-limited performance of an air-cooled aircraft-engine cylinder

Effect of exhaust pressure on knock-limited performance of an air-cooled aircraft-engine cylinder

Date: June 1, 1948
Creator: Lord, Albert M; Heinicke, Orville H & Stricker, Edward G
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of Exhaust Pressure on the Cooling Characteristics of a Liquid-Cooled Engine

Effect of Exhaust Pressure on the Cooling Characteristics of a Liquid-Cooled Engine

Date: January 20, 1947
Creator: Doyle, Ronald B. & Desmon, Leland G.
Description: Data for a liquid-cooled engine with a displacement volume of 1710 cubic inches were analyzed to determine the effect of exhaust pressure on the engine cooling characteristics. The data covered a range of exhaust pressures from 7 to 62 inches of mercury absolute, inlet-manifold pressures from 30 to 50 inches of mercury absolute, engine speeds from 1600 to 3000 rpm, and fuel-air ratios from 0.063 to 0.100. The effect of exhaust pressure on engine cooling was satisfactorily incorporated in the NACA cooling-correlation method as a variation in effective gas temperature with exhaust pressure. Large variations of cylinder-head temperature with exhaust pressure were obtained for operation at constant charge flow. At a constant charge flow of 2 pounds per second (approximately 1000 bhp) and a fuel-air ratio of 0.085, an increase in exhaust pressure from 10 to 60 inches of mercury absolute resulted in an increase of 40 F in average cylinder-head temperature. For operation at constant engine speed and inlet-manifold pressure and variable exhaust pressure (variable charge flow), however, the effect of exhaust pressure on cylinder-head temperature is small. For example, at an inlet-manifold pressure of 40 inches of mercury absolute, an engine speed of 2400 rpm.- and a fuel-air ...
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust pressure on the cooling characteristics of an air-cooled engine

Effect of exhaust pressure on the cooling characteristics of an air-cooled engine

Date: March 1, 1947
Creator: Valerino, Michael F; Kaufman, Samuel J & Hughes, Richard F
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust pressure on the performance of a 12-cylinder liquid-cooled engine

Effect of exhaust pressure on the performance of a 12-cylinder liquid-cooled engine

Date: July 1, 1947
Creator: Desmon, Leland G & Doyle, Ronald B
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of exhaust pressure on the performance of an 18-cylinder air-cooled radial engine with a valve overlap of 40 degrees

Effect of exhaust pressure on the performance of an 18-cylinder air-cooled radial engine with a valve overlap of 40 degrees

Date: March 1, 1947
Creator: Boman, David S; Nagey, Tibor F & Doyle, Ronald B
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system

The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system

Date: November 1, 1942
Creator: Humble, Leroy V
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Date: January 1, 1940
Creator: Stickle, George W; Naiman, Irven & Crigler, John L
Description: Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.
Contributing Partner: UNT Libraries Government Documents Department
Effect of explicit representation of detailed stratigraphy on brine and gas flow at the Waste Isolation Pilot Plant

Effect of explicit representation of detailed stratigraphy on brine and gas flow at the Waste Isolation Pilot Plant

Date: April 1, 1996
Creator: Christian-Frear, T.L. & Webb, S.W.
Description: Stratigraphic units of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) disposal room horizon includes various layers of halite, polyhalitic halite, argillaceous halite, clay, and anhydrite. Current models, including those used in the WIPP Performance Assessment calculations, employ a ``composite stratigraphy`` approach in modeling. This study was initiated to evaluate the impact that an explicit representation of detailed stratigraphy around the repository may have on fluid flow compared to the simplified ``composite stratigraphy`` models currently employed. Sensitivity of model results to intrinsic permeability anisotropy, interbed fracturing, two-phase characteristic curves, and gas-generation rates were studied. The results of this study indicate that explicit representation of the stratigraphy maintains higher pressures and does not allow as much fluid to leave the disposal room as compared to the ``composite stratigraphy`` approach. However, the differences are relatively small. Gas migration distances are also different between the two approaches. However, for the two cases in which explicit layering results were considerably different than the composite model (anisotropic and vapor-limited), the gas-migration distances for both models were negligible. For the cases in which gas migration distances were considerable, van Genuchten/Parker and interbed fracture, the differences between the two models were fairly insignificant. Overall, this ...
Contributing Partner: UNT Libraries Government Documents Department
Effect of Explosive Impacting on Uranium

Effect of Explosive Impacting on Uranium

Date: April 23, 1964
Creator: Burditt, R. B.; Carey, W. T. & Coughlen, C. P.
Description: Abstract: The tensile and yield strengths of both cast and wrought uranium discs were substantially increased by explosively impacting them at room temperature and at 375 deg F. However, the room-temperature impacting caused gross damage in the cast material and slight internal damage in the wrought material at the highest impacting pressures. Impacting at 375 deg F, which is just above the brittle-ductile transition temperature for uranium, was the most effective method for increasing the strengths with no damage to either the cast or wrought material. This impacted material retained some of its increased strength after a low temperature (425 deg C) vacuum anneal that greatly increased the elongation. A salt anneal caused a partial recrystallization in the impacted cast uranium. (auth).
Contributing Partner: UNT Libraries Government Documents Department
EFFECT OF EXPLOSIVE IMPACTING ON URANIUM

EFFECT OF EXPLOSIVE IMPACTING ON URANIUM

Date: June 17, 1963
Creator: Burditt, R.B.; Carey, W.T. & Coughlen, C.P.
Description: The tensile and yield strengths of both cast and wrought uranium discs were substantially increased by explosively impacting them at room teraperature and at 375 deg F. However, the room-temperature impacting caused gross damage in the cast material and slight internal damage in the wrought material at the highest impacting pressures. Impacting at 375 deg F, which is just above the brittie-ductile transition temperature for uranium, was the most effective method for increasing the strengths with no damage to either the cast or wrought material. This impacted material retained some of its increased strengih after a lowtemperature (425 deg C) vacuum anneal that greatly increased the elongation. A salt anneal caused a partial recrystallization in the impacted cast uranium. (auth)
Contributing Partner: UNT Libraries Government Documents Department
Effect of Exposure Site on Weather Resistance of Porcelain Enamels Exposed for Three Years

Effect of Exposure Site on Weather Resistance of Porcelain Enamels Exposed for Three Years

Date: April 10, 1962
Creator: Moore, Dwight G. & Potter, Alan
Description: From Introduction: "The present report describes the condition of all of the porcelain enamels after exposure for 3 yr."
Contributing Partner: UNT Libraries Government Documents Department
The Effect of Extending the Length of the Coupling Coils in a MuonIonization Cooling Channel

The Effect of Extending the Length of the Coupling Coils in a MuonIonization Cooling Channel

Date: November 10, 2007
Creator: Green, Michael A.
Description: RF cavities are used to re-accelerate muons that have beencooled by absorbers that are in low beta regions of a muon ionizationcooling channel. A superconducting coupling magnet (or magnets) arearound or among the RF cavities of a muon ionization-cooling channel. Thefield from the magnet guides the muons so that they are kept within theiris of the RF cavities that are used to accelerate the muons. Thisreport compares the use of a single short coupling magnet with anextended coupling magnet that has one or more superconducting coils aspart of a muon-cooling channel of the same design as the muon ionizationcooling experiment (MICE). Whether the superconducting magnet is shortand thick or long and this affects the magnet stored energy and the peakfield in the winding. The magnetic field distribution also affects is themuon beam optics in the cooling cell of a muon coolingchannel.
Contributing Partner: UNT Libraries Government Documents Department
The effect of external shape upon the drag of a scoop

The effect of external shape upon the drag of a scoop

Date: July 1, 1941
Creator: Hill, Paul R
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The effect of external stiffening ribs on the rolling power of ailerons on a swept wing

The effect of external stiffening ribs on the rolling power of ailerons on a swept wing

Date: October 25, 1956
Creator: Stephens, Emily W
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Effect of Extrusion Temperature on the Microstructural Development of Powder Metallurgy Ti-47A1-2Cr-1Nb-1Ta Alloy

Effect of Extrusion Temperature on the Microstructural Development of Powder Metallurgy Ti-47A1-2Cr-1Nb-1Ta Alloy

Date: June 29, 2000
Creator: Hsiung, L. & Nieh, T.G.
Description: Effect of extrusion temperatures on the microstructural development of a powder metallurgy (PM) Ti-47Al-2Cr-1Nb-1Ta (at. %) alloy has been investigated. Microstructure of the PM alloy extruded at 1150 C consists of a fine-grained ({gamma} + {alpha}{sub 2}) two-phase structure in association with coarse grains of metastable B2 (ordered bcc) phase. In addition, fine {omega} (ordered hexagonal) particles are also found within some B2 grains. The PM alloy containing the metastable B2 grains displays a low-temperature superplastic behavior, in which a tensile elongation of 310% is obtained at 800 C under a strain rate of 2 x 10{sup -5} s{sup -1}. It is suggested that the decomposition of metastable B2 phase and microstructural evolution during the deformation play a crucial role in the low-temperature superplasticity of the PM TiAl alloy. A refined fully-lamellar (FL) microstructure with alternating {gamma} and {alpha}{sub 2} lamellae is developed within the PM alloy extruded at 1400 C. The creep resistance of the refined FL-TiAl alloy is found to be superior to those of the TiAl alloys fabricated by conventional processing techniques. Creep mechanisms for the PM alloy with a refined FL microstructure are critically discussed according to TEM examination of deformation substructure.
Contributing Partner: UNT Libraries Government Documents Department
Effect of fabric deflection at high speeds on the aerodynamic characteristics of the horizontal tail surface of an SB2D-1 airplane

Effect of fabric deflection at high speeds on the aerodynamic characteristics of the horizontal tail surface of an SB2D-1 airplane

Date: June 1, 1945
Creator: Korycinski, Peter F
Description: None
Contributing Partner: UNT Libraries Government Documents Department