UNT Libraries Government Documents Department - 342 Matching Results

Search Results

Mica-Bearing Pegmatites of New Hampshire: a Preliminary Report

Description: From abstract: Mica has been mined in New Hampshire since 1803. Production from 1908 through 1939 has aggregated 13,326,990 pounds of sheet and punch mica, an annual average of 416,470 pounds. Since 1931 production has been below this average, because of economic conditions rather than depletions. The mica-bearing pegmatites of the Grafton and Keene districts occur mostly in sillimanite-mica schist adjacent to large areas of biotite gneiss. The pegmatite bodies range from a fraction of an inch to more than 200 feet in thickness; most of them are crosscutting, and about 75 percent strike northeast. Mica occurs sporadically in most of them but where present in commercial quantities it is localized in one or more of the following zones: (1) In quartz-plagioclase-muscovite zones 2 to 10 feet from the walls of large pegmatite bodies, (2) in or near quartz masses that occur mostly near the centers of the bodies, (3) in thin dikes 5 to 15 feet thick or in similar offshoots from larger bodies, (4) within large pegmatite bodies, in more or less tabular streaks or zones composed principally of plagioclase, quartz, and muscovite.
Date: 1942
Creator: Olson, J. C.

Subsurface Geology and Oil and Gas Resources of Osage County, Oklahoma: Part 11. Summary of Subsurface Geology with Special Reference to Oil and Gas

Description: From foreword: This report on the subsurface geology of Osage County, Okla., describes the structual features, the character of the oil- and gas-producing beds, and the localities where additional oil and gas may be found. It embodies a part of the results of a subsurface geologic investigation of the Osage Indian Reservation, which coincides in area with Osage County. The investigation was conducted by a field party of the Geological Survey of the United States Department of the Interior from 1934 to 1937 and involved the study of the records of about 17,000 wells that have been drilled in Osage County.
Date: 1942
Creator: Bass, N. Wood

Occurrences of Molybdenum Minerals in Alaska

Description: Abstract: In the accompanying report reference is made to all of the deposits in Alaska in which molybdenum minerals have been definitely recognized and reported. None of the deposits have been mined commercially, and none of them have been prospected thoroughly enough to afford quantitative estimates as to their tenor and potential reserves ; in fact, at only a few of the localities has there been more than surficial testing. Forty-one separate and distinct localities where molybdenum minerals occur are listed, and the available information on factors of geologic significance regarding each occurrence is given. A small-scale map of Alaska on which the various localities are indicated forms part of the bulletin, and in the text are extensive references to the various published reports and records of the Survey upon which the statements are based. In spite of the widespread distribution of molybdenum mineralization in Alaska, the remoteness of many of the localities, their handicap through dearth of transportation facilities and labor supplies, and the already wellsupplied condition of the American market for molybdenum ores discourage the early development of any of the known deposits or search for them in unsurveyed areas. These draw-backs will doubtless become -less important factors as the settlement and development of Alaska as a whole takes place. It is, therefore, with a view to the future that one must consider these deposits, and from that standpoint it becomes evident that some of them merit watchful consideration.
Date: 1942
Creator: Smith, Philip S.

The Tin-Spodumene Belt of the Carolinas: a Preliminary Report

Description: From abstract: Cassiterite and spodumene, of possible economic importance, occur in a belt, 24.5 miles long and 1.8 miles in maximum width, extending southwestward from Lincolnton to Grover, N. C. This belt is in the Piedmont province, an upland with an average altitude of 1,000 feet, and is readily accessible by rail and highway. The region is underlain by crystalline limestone, quartzite, schists, gneisses, and granite. The rocks strike northeast and, in most of the belt, dip steeply northwest. Most of them are deeply weathered.
Date: 1942
Creator: Kesler, Thomas L.

Nickel-Copper Deposits on the West Coast of Chichagof Island, Alaska

Description: From abstract: On the west coast of Chichagof Island, southeastern Alaska, are three nickel-copper deposits that consist of norite containing the sulfide minerals pyrrhotite, pentlandite, and chalcopyrite. The deposits are within less than a mile of each other and are, by water, 160 miles southwest of Juneau and 70 miles northwest of Sitka. The norite is part of a stock, about 5 square miles of which is above sea level. Other rocks of the stock are amphibolite, amphibolitic norite, gabbro, diorite, quartz diorite, monzonite, granite, pegmatites, quartz veins, and schist inclusions. The stock is intrusive into a Lower Cretaceous (?) graywacke formation and an Upper Triassic (?) greenstone formation, both of which are now metamorphosed to schist.
Date: 1942
Creator: Pecora, W. T.

Tin Deposits of Northern Lander County, Nevada

Description: From abstract: Tin-bearing veinlets are exposed in a small area near Izenhood Ranch, 22 miles north of Battle Mountain, Nev. They occur in thick rhyolitic flows of Miocene (?) age, and wood tin, found in the gravels of arroyos that head in the surrounding rhyolite, presumably comes from -other veinlets not yet discovered. The exposed veinlets are about 20 feet in maximum length and a quarter of an inch in average thickness. Parallel and reticulating veinlets form lodes 4 to 6 feet thick and 15 or 20 feet long. Virtually no cassiterite is disseminated in the wall rock.
Date: 1942
Creator: Fries, Carl, Jr.

Nickel-Copper Deposit at Snipe Bay, Baranof Island, Alaska

Description: Abstract: At Snipe Bay, on the outer coast of Baranof Island, about 46 miles southeast of Sitka in southeastern Alaska, is a nickelcopper deposit that consists of a mass of basic rock intruded into quartzite and quartz schist. Neither the size nor the grade of the deposit is adequately known. Natural exposures and those in a few prospect openings indicate that to an assumed depth of about 130 feet below the lowest point on the outcrop there is a reserve of about 430,000 tons of low-grade nickelbearing material, which, to judge from available assays and from comparison with similar material from other places, probably does not contain more than 0.3 percent each of nickel and copper. The deposit thus appears too small and of too low grade to permit the recovery of the nickel and copper except at a considerable financial loss; but as the location is favorable for largescale, low-cost development, further prospecting may be justified, in the hope that a moderate amount of surface stripping, plus a few diamond-drill holes, might indicate that the deposit is larger, and possibly of higher grade, than it is safe to infer from the available data.
Date: 1942
Creator: Reed, John C. & Gates, George O.

Antimony Deposits of the Stampede Creek Area, Kantishna District, Alaska

Description: From abstract: The Stampede Creek area lies about 120 miles southwest of Fairbanks, Alaska. It is most readily accessible by air during the summer and by tractor road during the winter. Since 1936 approximately 2,400 tons of shipping-grade antimony ore and concentrates, containing about 1,300 tons of metallic antimony, have been produced at the Stampede mine. The mine was closed down in the spring of 1941, principally because of the high cost of transportation. The area is underlain largely by metamorphosed rocks of the Birch Creek schist. The schist has been warped and crumpled into many broad, open folds which strike northeast and also plunge to the northeast. The Stampede mine is in the schistose quartzite member of the Birch Creek schist.
Date: 1942
Creator: White, Donald Edward

Nickel-Copper Deposit at Funter Bay, Admiralty Island, Alaska

Description: From abstract: The nickel-copper deposit near the north end of Admiralty Island, about 18 miles in an airline west of Juneau, in southeastern Alaska, consists of a basic sill which averages somewhat more than 100 feet in thickness. The sill, which dips eastward, is intrusive into a thick sequence of phyllite and various types of schist. The rock of the sill consists principally of the silicate minerals labradorite and olivine, but it also contains magnetite and the sulfides pyrrhotite, pentlandite, and chalcopyrite. It assays, on the average, about 0.34 percent nickel and 0.35 copper, which are doubtless mostly in the pentlandite and chalcopyrite respectively but are probably constituents of other minerals also. A significant proportion of nickel and copper is probably contained in the olivine and perhaps in the pyrrhotite.
Date: 1942
Creator: Reed, John C.

Vanadium Deposits of Colorado and Utah: a Preliminary Report

Description: From abstract: Deposits of vanadium-bearing sandstone are widely distributed in western Colorado and eastern Utah and have been the principal domestic source of vanadium, uranium, and radium. Except during a few years when operations were relatively small, deposits at one or more places in this region have been intensively mined since 1909. Production has increased considerably each year since 1937.
Date: 1942
Creator: Fischer, Richard P.

Tin Deposits of Irish Creek, Virginia

Description: From abstract: Cassiterite was discovered along Irish Creek in the Blue Ridge in the northern part of Rockbridge County, Va., in 1846, but active prospecting and development work were not begun until 1884. The production has been small, probably less than 1,000 tons of ore, and has come chiefly from workings on Panther Run, a small tributary near the headwaters of Irish Creek.
Date: 1942
Creator: Koschmann, A. H.; Glass, J. J. & Vhay, J. S.

Strength tests of thin-walled elliptic duralumin cylinders in pure bending and in combined pure bending and torsion

Description: An analysis is presented of the results of tests made by the Massachusetts Institute of Technology and by the National Advisory Committee for Aeronautics on an investigation of the strength of thin-walled circular and elliptic cylinders in pure bending and in combined torsion and bending. In each of the loading conditions, the bending moments were applied in the plane of the major axis of the ellipse.
Date: June 1, 1942
Creator: Lundquist, Eugene E. & Stowell, Elbridge Z.

The effect of valve cooling upon maximum permissible engine output as limited by knock

Description: A Wright GR-1820-G200 cylinder was tested over a wide range of fuel-air ratios at maximum permissible power output as limited by knock with three different degrees of valve cooling. The valves used were stock valves (solid inlet valve and hollow sodium-cooled exhaust valve), hollow valves with no coolant, and hollow valves with flowing water as a coolant. Curves showing the variation in maximum permissible values of inlet-air pressure, indicated mean effective pressure, cylinder charge, and indicated specific fuel consumption with change in fuel-air ratio and valve cooling are shown. The use of valves cooled by a stream of water passing through their hollow interiors permitted indicated mean effective pressures 10 percent higher than the mean effective pressures permissible with stock valves when the engine was operated with fuel-air ratios from 0.055 to 0.065. Operation of the engine with lean mixtures with uncooled hollow valves resulted in power output below the output obtained with the stock valves. The data show an increase in maximum permissible indicated mean effective pressure due to cooling the valves, which averages only 2.1 percent with fuel-air ratios from 0.075 to 0.105.
Date: September 1, 1942
Creator: Munger, Maurice; Wilsted, H D & Mulcahy, B A

Test of single-stage axial-flow fan

Description: A single-stage axial fan was built and tested in the shop of the propeller-research tunnel of the NACA. The fan comprised a simple 24-blade rotor having a diameter of 21 inches and a solidity of 0.86 and a set of 37 contravanes having a solidity of 1.33. The rotor was driven by a 25-horsepower motor capable of rotating at a speed of 3600 r.p.m. The fan was tested for volume, pressure, and efficiency over a range of delivery pressures and volumes for a wide range of contravane and blade-angle settings. The test results are presented in chart form in terms of nondimensional units in order that similar fans may be accurately designed with a minimum effort. The maximum efficiency (88 percent) was obtained by the fan at a blade angle of 30 degrees and a contravane angle of 70 degrees. An efficiency of 80 percent was obtained by the fan with the contravanes removed.
Date: January 1, 1942
Creator: Bell, E Barton

Shear lag in box beams methods of analysis and experimental investigations

Description: The bending stresses in the covers of box beams or wide-flange beams differ appreciably from the stresses predicted by the ordinary bending theory on account of shear deformation of the flanges. The problem of predicting these differences has become known as the shear-lag problem. The first part of this paper deals with methods of shear-lag analysis suitable for practical use. The second part of the paper describes strain-gage tests made by the NACA to verify the theory. Three tests published by other investigators are also analyzed by the proposed method. The third part of the paper gives numerical examples illustrating the methods of analysis. An appendix gives comparisons with other methods, particularly with the method of Ebner and Koller.
Date: January 1, 1942
Creator: Kuhn, Paul & Chiarito, Patrick T

High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane

Description: Report presents the results of force tests made of a 1/8-scale model of a twin-engine low-wing transport airplane in the NACA 8-foot high-speed tunnel to investigate compressibility and interference effects of speeds up to 450 miles per hour. In addition to tests of the standard arrangement of the model, tests were made with several modifications designed to reduce the drag and to increase the critical speed.
Date: January 1, 1942
Creator: Becker, John V & LEONARD LLOYD H

High-Speed Tests of Conventional Radial-Engine Cowlings

Description: The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the NACA 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination were used in the tests.
Date: January 1, 1942
Creator: Robinson, Russell G & Becker, John V

Flutter calculations in three degrees of freedom

Description: The present paper is a continuation of the general study of flutter published in NACA reports nos. 496 and 685. The paper is mainly devoted to flutter in three degrees of freedom (bending, torsion, and aileron) for which a number of selected cases have been calculated and presented in graphical form. The results are analyzed and discussed with regard to the effects of structural damping, of fractional-span ailerons, and of mass-balancing. The analysis shows that more emphasis should be put on the effect of structural damping and less on mass-balancing. The conclusion is drawn that a definite minimum amount of structural damping, which is usually found to be present, is essential in the calculations for an adequate description of the flutter case. Theoretical flutter predictions are thus brought into closer agreement with the facts of experience. A brief discussion is included of a particular biplane that had experienced flutter at about 200 miles per hour. Some simplifications have been achieved in the method of calculation. (author).
Date: January 1, 1942
Creator: Theodorsen, Theodore & Garrick, I E