Search Results

open access

Theoretical Investigation of the Effects of the Artificial-Feel System on the Maneuvering Characteristics of the F-89 Airplane

Description: The possibility of overshooting the anticipated normal acceleration as a result of the artificial-feel characteristics of the F-89C airplane at a condition of minimum static stability was investigated analytically by means of an electronic simulator. Several methods of improving the stick-force characteristics were studied. It is shown that, due to the lag in build-up of the portion of the stick force introduced by the bobweight, it would be possible for excessive overshoots of normal acceleration to occur in abrupt maneuvers with reasonable assumed control movements. The addition of a transient stick force proportional to pitching acceleration (which leads the normal acceleration) to prevent this occurring would not be practical due to the introduction of an oscillatory mode to the stick-position response. A device to introduce a viscous damping force would Improve the stick-force characteristics so that normal acceleration overshoots would not be likely, and the variation of the maximum stick force in rapid pulse-type maneuvers with duration of the maneuver then would have a favorable trend.
Date: December 31, 1952
Creator: Abramovitz, Marvin; Schmidt, Stanley F. & Belsley, Steven E.
Partner: UNT Libraries Government Documents Department
open access

Diffusion of Uranium with Various Transitional Metals; DIFFUSION DE L'URANIUM AVEC QUELQUES METAUX DE TRANSITION

Description: The diffusion process in uranium and its alloys was studied from 550 to 1075 deg C with diffusion couples of U with Zr, Mo, Ti, and Nb and with the alloys U--Nb and U--Mo. A brief description is given of the experimental methods. Results relative to the concentration-penetration curves are presented, and the coefficients of diffusion are calculated. The equilibrium diagram was established for the U--Zr system. The results obtained by micrographic examination, microhardness measurements, and autoradiography are compared with each other. The mechanisms of diffusion are investigated by studying the Kirkendall effect and calculating the Darken intrinsic coeffi cients in the U--Zr and U--UMo diffusion couples. (J.S.R.)
Date: October 31, 1959
Creator: Adda, Y. & Philibert, J.
Partner: UNT Libraries Government Documents Department
open access

THREE NEW DELAYED ALPHA EMITTERS OF LOW MASS

Description: Two new positron active isotopes, B{sup 8} and Na{sup 20}, have been found to decay to excited states of Be{sup 8} and Ne{sup 20}, which in turn decay 'instantaneously' by alpha emission. Their half-lives are 0.65 {+-} 0.1 sec. and 1/4 sec. respectively. N{sup 12} is also found to have a low energy positron group which leads to an {alpha}-unstable excited state in C{sup 12}. The masses of B{sup 8} and Na{sup 20} are 8.027 and 20.015 respectively. B{sup 8} decays by a 13.7 {+-} 0.3 Mev positron, through the same excited state of Be{sup 8} as does Li{sup 8}. Estimates of the energies of the excited state in C{sup 12} and Ne{sup 20} are made.
Date: May 31, 1950
Creator: Alvarez, Luis W.
Partner: UNT Libraries Government Documents Department
open access

Sodium Reactor Experiment (Sre) Shielding Evaluation for Thermal Neutron Streaming at Reactor Vessel Coolant Pipe Penetrations

Description: The experimental program performed in the SRE auxiliary and main primary galleries was part of a program to determine the adequacy of the shielding configuration for the SRE. The work discussed in this report is concerned with analysis of neutron streaming at coolant pipe penetrations of the reactor vessel, analysis of the shielding required, testing and evaluation of recommended shielding, and measurement and correlation of neutron streaming in labyrinths with theory. The activation analysis method using zinc sheets which was developed for the program of determining thermal neutron streaming in the SRE primary galleries was proven to be versatile, accurate, and reliable. A modified form of the theoretical method of Price, Horton, and Spinney, used to determine neutron scattring through labyrinths, was found to agree favorably with the experimental results obtained from the SRE primary galleries. The theoretical attenuation method used no determine the neutron shield configuration installed in the auxiliary primary gallery was found to give an overestimate of the actual attenuation properties of this shield. The neutron shield configuration installed in the auxiliary primary gallery proved to be adequate in reducing the thermal neutron streaming flux to an acceptable level. It is concluded that both SRE primary galleries are now adequately shielded to prevent excessive neutron- induced activation of the components and equipment located therein. (auth)
Date: October 31, 1959
Creator: Anderson, F. D.
Partner: UNT Libraries Government Documents Department
open access

Steady State Temperature Distributions in Hollow Slugs

Description: This document is a sequel to HW-30226, "Steady State Temperature Distribution in a Solid Slug." A primary feature of the present as well as the former paper is a treatment of the stand heat flow equation in a manner which accounts accurately for the dependence of the thermal conductivity, K, on temperature, v.
Date: December 31, 1953
Creator: Anselone, P. M.; Banks, D. O. & Dean, R. Y.
Partner: UNT Libraries Government Documents Department
open access

Buildup and Decay Factors for Members of the U-232 Decay Chain

Description: Activity ratios for the important members of the U/sup 232/ chain are presented in tabular form. These ratios are presented for initially pure U/sup 232/, initially pure Th/sup 228/ and initially pure Ra/sup 224/.- (auth)
Date: July 31, 1958
Creator: Arnold, E.D.
Partner: UNT Libraries Government Documents Department
open access

A NEW VALENCE STATE OF AMERICIUM, Am(VI)

Description: No Description Available.
Date: October 31, 1951
Creator: Asprey, L. B.; Stephanou, S. E. & Penneman, R. A.
Partner: UNT Libraries Government Documents Department
open access

A Pilot Plant for the Reduction of Uranium Hexafluoride to Uranium Tetrafluoride with Trichloroethylene

Description: Pilot plant experiments are described in which trichloroethylene was used for the reduction of uranium hexafluoride to uranium tetrafluoride. After unsatisfactory preliminary results with liquid phase reduction, satisfactory results were obtained with a vapor phase reduction system. It was found that vapor phase reduction at approximately 450 deg F, produced a low density product which contained only small quantities of uranium(VI); sintering the uranium tetrafluoride in a hydrogen fluoride atmosphere increased the product density to approximately 3 g/cc. The reduction was essentially complete, and the effluent gas contained less than 1 ppm of uranium hexafluoride. The purity of the uranium tetrafluoride produced was equivalent to that of the uranium hexafluoride used as feed. A complete discussion is given of the operation of the various parts of the system. (auth)
Date: May 31, 1956
Creator: Baker, J. E.; Klaus, H. V.; Schmidt, R. A. & Smiley, S. H.
Partner: UNT Libraries Government Documents Department
open access

The effects of various parameters including Mach number on propeller blade flutter with emphasis on stall flutter

Description: Report presenting an investigation of the effects of many of the parameters significant to wing flutter on several untwisted rotating models to determine their significance with respect to stall flutter of propeller blades. The parameters included torsional stiffness, section thickness ratio, sweepback, length-chord ratio, section center-of-gravity location, blade taper, Mach number, and fluid density. Results regarding the considerations on method of presentation, experimental data and discussion, some possible applications, and a comparison of experiment with classical-flutter theory are provided.
Date: January 31, 1951
Creator: Baker, John E.
Partner: UNT Libraries Government Documents Department
open access

Interpretation and Evaluation of the Uranium Occurences Near Goodsprings, Nevada: Final Report

Description: Abstract: The uranium occurrences near Goodsprings, Clark Co., Nevada, are divided into two distinct types which differ from each other in geographic distribution, localization of mineralization, mineralogy and origin. None of the known deposits is of present commercial significance and therefore this study emphasizes the genetic rather than the economic aspects.
Date: December 31, 1954
Creator: Barton, Paul B., Jr. & Behre, Charles H., Jr.
Partner: UNT Libraries Government Documents Department
open access

ELECTRODEPOSITION OF NICKEL ON URANIUM

Description: Electrodeposited nickel coatings on uranium for protection from destructive corrosion in boiling water wns investigated. Correlation between the pretreatment of the uranium and subsequent protection by thin nickel coatings was established. Thin electrodeposited nickel coatings provide better protection when applied to a matte surface produced by blasting with an aqueous suspension of silica (100 mesh) followed by a cathodic treatment in 35 wt% sulfuric acid than when applied to the rough surfaces produced on uranium by anodic pretreatments and acid pickling. Blistering of nickel electrodeposits arising from hydrogen was encountered and eliminated. (auth)
Date: August 31, 1954
Creator: Beard, A. P. & Crooks, D. D.
Partner: UNT Libraries Government Documents Department
open access

Pulsed Neutron Experiments With Fast Assemblies

Description: "The pulsed source technique consists of introducing repeated short bursts of neutrons into a subcritical assembly, and following the decay of the leakage flux as a function of time...It is noted that plotting the decay constant as a function of buckling gives an apparently accurate way to extrapolate to prompt critical. The pulsed source technique can also be used to calibrate control rod and poison worth, and will give some estimate of the prompt neutron lifetime."
Date: October 31, 1957
Creator: Bengston, Joel & Passell, Lawrence
Partner: UNT Libraries Government Documents Department
open access

Basic Studies of the Separation of Uranium Hexafluoride from Mixtures Containing Chlorine Trifluoride and Hydrogen Fluoride

Description: Processes for the conversion of uranium compounds or uranium metal to uranium hexafluoride ordinarily involve the use of a powerful fluorinating agent. Elemental fluorine is used when the scale of operations justifies the construction of a fluorine generating plant, but for smaller operation the use of the interhalogens of fluorine has definite advantages. These compounds provide a high concentration of fluorinating power at moderate temperatures and pressures and are more easily stored and transported than fluorine. In addition, fluorinations in the liquid phase often proceed more smoothly than those with gaseous fluorine. However, the use of . the interhalogens introduces the problem of separating the uranium hexafluoride from the unreacted reagent and from any by-products which may have been formed. The present work is concerned with the determination of the phase equilibrai among the materials uranium hexafluoride, chlorine trifluoride, and hydrogen fluoride. metal with chlorine trifluoride-hydrogen fluoride solutions or as a result of treating many uranium compounds and ores with chlorine trifluoride. These phase equilibria define the physical conditions necessary for separating the components by the processes of crystallization or distillation and have made possinle the successful Operation of a pilot plant for the direct recovery of uranium hexafluoride from spent metallic uranium fuel elements. (auth)
Date: October 31, 1958
Creator: Bernhardt, H. A.; Barber, E. J.; Davis Jr., W. & McGill, R. M.
Partner: UNT Libraries Government Documents Department
open access

THEORETICAL ESTIMATE OF MAXIMUM POSSIBLE NUCLEAR EXPLOSION

Description: The maximum nuclear accident which could occur in a Na-cooled, Be moderated, Pu and power producing reactor is estimated theoretically. (T.R.H.) 2O82 Results of nuclear calculations for a variety of compositions of fast, heterogeneous, sodium-cooled, U-235-fueled, plutonium- and power-producing reactors are reported. Core compositions typical of plate-, pin-, or wire-type fuel elements and with uranium as metal, alloy, and oxide were considered. These compositions included atom ratios in the following range: U-23B to U-235 from 2 to 8; sodium to U-235 from 1.5 to 12; iron to U-235 from 5 to 18; and vanadium to U-235 from 11 to 33. Calculations were performed to determine the effect of lead and iron reflectors between the core and blanket. Both natural and depleted uranium were evaluated as the blanket fertile material. Reactors were compared on a basis of conversion ratio, specific power, and the product of both. The calculated results are in general agreement with the experimental results from fast reactor assemblies. An analysis of the effect of new cross-section values as they became available is included. (auth)
Date: January 31, 1950
Creator: Bethe, H.A.
Partner: UNT Libraries Government Documents Department
open access

The Hard-Core Pinch. I

Description: This report analyzes a linear, hard-core pinch tube built to examine tubes afflicted by small-scale instabilities evident from many observations.
Date: July 31, 1959
Creator: Birdsall, D. H.; Colgate, Stirling A. & Furth, Harold P.
Partner: UNT Libraries Government Documents Department
open access

The Hard-Core Pinch. II

Description: This report describes a toroidal version of the hard-core pinch and the additional information it can obtain to what the analogous linear pinch can get.
Date: July 31, 1959
Creator: Birdsall, D. H.; Colgate, Stirling A. & Furth, Harold P.
Partner: UNT Libraries Government Documents Department
open access

The Hard-Core Pinch. Part I

Description: It is well known that a pinch column with internal H/sub Z/ and external conducting shell can be made grossly stable, but that small-scale instabilities persist; especiaily in the tubular region of maximum current density. To investigate further these small-scale instabilities of the stabilized pinch,'' we are using 12-in.-i.d. linear pinch tube with a 3-in.-o.d. insulated center rod. By controlling a current along this rod, as well as a current along external conducting straps, and a third current in an external H/sub z/ coil, it is possible to create many grossly stable pinch configurations. The small-scale stability of the tubular region of maximum current density can thus be studied for a wide range of internal and external magnetic field vectors. The magnetic field distribution in each discharge is obtained by a string of 10 magnetic pick- up loops. The distribution of plasma density is determined by modulating the inner or outer wall current and measuring the radial velocity of the resultant compressional Alfven waves. In one experiment, an initial H/sub z/ is entrapped in plasma by preionization, and then pushed radially outward from the rod by a rising H/sub theta /. The resultant field distribution, in which H/sub theta / everywhere falls more rapidly than 1/r, should have absolute hydromagnetic stability. The persistence of small-scale instabilities, as observed by the magnetic probes, in this inverse stabilized pinch'' suggests that the basic trouble is nonhydromagnetic. It is also found that, when the magnetic field approximates a vacuum field distribution, perfectly smooth and reproducible probe signals can be obtained. The absolute plasma current densities at which nearvacuum field distributions have been found stable are larger than current densities at which the 'stabilized pinch'' and inverse stabilized pinch'' distributions have been found unstable. (auth)
Date: July 31, 1959
Creator: Birdsall, D.H.; Colgate, S.A. & Furth, H.P.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen