1,540 Matching Results

Search Results

Advanced search parameters have been applied.

In Situ Redox Manipulation of Subsurface Sediments from Fort Lewis, Washington: Iron Reduction and TCE Dechlorination Mechanisms

Description: The feasibility of chemically treating sediments from the Ft. Lewis, Washington, Logistics Center to develop a permeable barrier for dechlorination of TCE was investigated in a series of laboratory experiments.
Date: March 17, 2000
Creator: Szecsody, James E.; Fruchter, Jonathan S.; Sklarew, Deborah S. & Evans, John C.
Partner: UNT Libraries Government Documents Department

Electrochemical Reduction of Titanium in Nonaqueous Solvents

Description: Abstract: Electrorefining of Ti in nonaqueous solvents has been studied by the U.S. Bureau of Mines as a method for recycling impure scrap Ti. Electrochemical behavior of Ti species was investigated using cyclic voltammetry. Research results showed that Ti metal can be dissolved in polar solvents such as dimethylformamide or dimethyl sulfoxide. However, deposition of Ti from these solvents was not successful. Several solvent systems were investigated for electrodepos.tion of Ti but no deposits were obtained. Reduction of Ti' complexes to Ti" proved to be straightforward, but reduction to lower oxidation states could not be confirmed. In dimethylformamide solutions, cyclic voltammetry results demonstrated the reduction of Ti to an oxidation state of less than three, but no Ti metal was identified. In dimethyl sulfoxide solutions containing LiCl, it was possible to deposit Li metal. After adding Ti salts to the solution, electrolysis quickly passivated the electrode. Deposition of Ti was also investigated in solutions of dimethoxyethane and propylene carbonate but, again, no reduction of Ti to oxidation states of less than three occurred. Therefore, the prospects for a nonaqueous electrorefining system for Ti metal do not appear promising.
Date: 1995
Creator: Sibrell, P. L.
Partner: UNT Libraries Government Documents Department

Synthetic Approaches to (smif)₂Ti (smif=1,3-di-(2-pyridyl)-2-azaallyl) Reveal Redox Non-Innocence and C-C Bond-Formation

Description: Article discussing synthetic approaches to (smif)₂Ti(smif=1,3-di-(2-pyridyl)-2-azallyl) revealing redox non-innocence and C-C bond-formation.
Date: July 25, 2012
Creator: Frazier, Brenda A.; Wolczanski, Peter T.; Keresztes, Ivan; DeBeer, Serena 1973-; Lobkovsky, Emil B.; Pierpont, Aaron W. et al.
Partner: UNT College of Arts and Sciences

Reduction of wave drag of wing-body combinations at supersonic speeds through body distortions

Description: Report presenting some methods providing sizable reductions in drag for aspect ratios of current interest. The drag savings are maintained over a wide Mach number range, particularly for low-aspect-ratio wings. A significant part of the drag reduction is found to be due to the nonaxisymmetric distortion.
Date: April 13, 1956
Creator: Pitts, William C.
Partner: UNT Libraries Government Documents Department

Determination of Shapes of Boattail Bodies of Revolution for Minimum Wave Drag

Description: By use of an approximate equation for the wave drag of slender bodies of revolution in a supersonic flow field, the optimum shapes of certain boattail bodies are determined for minimum wave drag. The properties of three specific families of bodies are determined, the first family consisting of bodies having a given length and base area and a contour passing through a prescribed point between the nose and base, the second family having fixed length, base area, and maximum area, and the third family having given length, volume, and base area. The method presented is easily generalized to determine minimum-wave-drag profile shapes which have contours that must pass through any prescribed number of points. According to linearized theory, the optimum profiles are found to have infinite slope at the nose but zero radius of curvature so that the bodies appear to have pointed noses, a zero slope at the body base, and no variation of wave drag with Mach number. For those bodies having a specified intermediate.diameter (that is, location and magnitude given), the maximum body diameter is shown to be larger, in general, than the specified diameter. It is also shown that, for bodies having a specified maximum diameter, the location of the maximum diameter is not arbitrary but is determined from the ratio of base diameter to maximum diameter.
Date: August 21, 1951
Creator: Adams, Mac C.
Partner: UNT Libraries Government Documents Department

The use of pure twist for drag reduction on arrow wings with subsonic leading edges

Description: Report presenting linearized-theory calculations of the drag reduction achieved by applying the first three terms of a power series for twist to flat delta wings. For the family of wings investigated, the maximum drag reduction is 2 percent in the medium sweepback range with a steady diminution in both directions. Results for the delta and arrow wings and the optimum settings are provided.
Date: August 1957
Creator: Grant, Frederick C.
Partner: UNT Libraries Government Documents Department

An Analysis of the Administration's Deficit Reduction Goal

Description: This report briefly discusses the Bush Administration's proposal to reduce the deficit between FY2004 and FY2009. It discusses the provisions of the FY2006 budget proposal in respect to the Administration's deficit reduction goal. CRS has constructed a modified baseline budget which, arguably, provides a “best guess” of the path of future deficits if current policy is extended. Under this alternative, the deficit is projected to rise to $425 billion in FY2009.
Date: March 2, 2005
Creator: Esenwein, Gregg A. & Labonte, Marc
Partner: UNT Libraries Government Documents Department

Combustion in the Wake as a Means of Body-Drag Reduction as Determined from Free-Flight Tests of 40-Millimeter Shells

Description: The results of free-flight drag tests of 40-millimeter shells conducted by the National Advisory Committee for Aeronautics for the Ballistic Research Laboratories, Ordnance Department, U. S. Army, are presented. A drag reduction at supersonic speeds of approximately 20 percent of the projectile's drag was obtained by combustion in the wake of the projectile in flight.
Date: 1953
Creator: Welsh, Clement J.
Partner: UNT Libraries Government Documents Department

Preliminary Tests of Blowers of Three Designs Operating in Conjunction with a Wing-Duct Cooling System for Radial Engines, Special Report

Description: This paper is one of several dealing with methods intended to reduce the drag of present-day radial engine installations and improve the cooling at zero and low air speeds, The present paper describes model wind-tunnel tests of blowers of three designs tested in conjunction with a wing-nacelle combination. The principle of operation involved consists of drawing cooling air into ducts located in the wing root at the point of maximum slipstream velocity, passing the air through the engine baffles from rear to front, and exhausting the air through an annular slot located between the propeller and the engine with the aid of a blower mounted on the spinner. The test apparatus consisted essentially of a stub wing having a 5-foot chord and a 15-foot span, an engine nacelle of 20 inches diameter enclosing a 25-horsepower electric motor, and three blowers mounted on propeller spinners. Two of the blowers utilize centrifugal force while the other uses the lift from airfoils to force the air out radially through the exit slot. Maximum efficiencies of over 70 percent were obtained for the system as a whole. Pressures were measured over the entire flight range which were in excess of those necessary to cool present-day engines, The results indicated that blowers mounted on propeller spinners could be built sufficiently powerful and efficient to warrant their use as the only, or chief, means of forcing air through the cooling system, so that cooling would be independent of the speed of the airplane.
Date: June 1939
Creator: Biermann, David & Valentine, E. Floyd
Partner: UNT Libraries Government Documents Department

Comparison of the minimum drag of two versions of a modified delta-wing fighter as obtained from flight tests of rocket-boosted models and equivalent bodies between Mach numbers of 0.80 and 1.64

Description: Report presenting an investigation to determine the reduction in minimum drag that could be obtained at supersonic speeds by redesigning the fuselage and reducing the wing and tail thickness of a modified delta-wing fighter-type airplane. Results regarding the mass-flow ratio, total-pressure recovery, and drag are provided.
Date: September 24, 1956
Creator: Hasting, Earl C., Jr. & Mitcham, Grady L.
Partner: UNT Libraries Government Documents Department

Fast Facts: Climate Change and UNDP

Description: Making poverty history and tackling climate change go hand-in-hand because receding forests, changing rainfall patterns and rising sea levels trap people in hardship and undermine their future. Studies in Ethiopia show that children exposed to drought in early childhood are 36 percent more likely to be malnourished five years later.
Date: October 2009
Creator: United Nations Environment Programme
Partner: UNT Libraries

Improved Grindability of Taconite Ores by Microwave Heating

Description: The 11.S. Bureau of Mines has conducted studies to utilize rapid microwave heating to stress fracture ore samples. Iron ores containing hematite, magnetite, and goethite were subjected to microwave energy in batch operations at 3 kW and heated to average maximum temperatures between 840 and 940 *C. Standard Bond grindability tests showed that microwave heating reduced the work index of iron ores by 10 to 24 pct. In a microwave chamber designed to simulate a continuous throughput operation at 3 kW, the grindability of a tacon-te ore was improved by 13 pct at a bulk temperature of 197 *C. Because stress cracking occurred at a lower temperature, less energy was consumed. To further improve the economics of microwave fracturing, higher powers up to 16 kW were used to rapidly heat samples to relatively low temperatures in a continuous, belt-fed applicator. A significant improvement of grindability was obtained with a larger rod mill feed size in comparison to a minus 6-mesh Bond feed.
Date: 1995
Creator: Walkiewicz, John W.; Lindroth, David P. & Clark, Andrea E.
Partner: UNT Libraries Government Documents Department

Some systematic model experiments of the bow-spray characteristics of flying-boat hulls operating at low speeds in waves

Description: Report discusses the results of testing on several models of flying boats, the XPB2M-1, the XPBB-1, the JRM-1, and 11 other models to determine the effect of bow form on the amount of spray thrown onto the windshield of a flying boat in rough water. Several recommendations for reducing the height and volume of spray are provided. Any change in the hull form that softens the impact between the hull and waves seems to reduce the spray.
Date: December 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Massed Group Desensitization in the Reduction of Anxiety

Description: The problem with which this investigation was concerned was that of determining the effectiveness of massed group desensitization in the reduction of anxiety. Thirty test-anxious nursing students who scored in the upper quartile on the Test Anxiety Questionnaire (TAQ) served as the subjects. The subjects were assigned by the use of a randomized block procedure to one of the following three groups matched on the basis of their pre-test TAQ scores: (1) desensitization, (2) placebo, and (3) control.
Date: August 1972
Creator: Dawley, Harold H., 1940-
Partner: UNT Libraries

Clarification of Redox Feed (1AF) by Filtration : A Semi-Works Study Progress, Redox Technical Data Study No. 8

Description: The following report was made to determine the effective clarity improvement, flow rate characteristics, and operational problems encountered on passing Redox uranium feed solution through sintered, modified Type 304 stainless steel filter elements.
Date: October 15, 1948
Creator: Cooper, V. R. & Coleman, E. M.
Partner: UNT Libraries Government Documents Department