Search Results

open access

Chemical Effects of Nuclear Transformations and Their Use in Making Labeled Compounds

Description: The chemical effects of nuclear transformations can be utilized to introduce the radioactive atoms produced into chemical species useful for tracer studies. Gas chromatography offers a means of separating the tagged compounds with high specific activity. A chromatographic apparatus for separating and identifying labeled compounds is described. Comparisons are made of this with other labeling techniques. (auth)
Date: January 1, 1957
Creator: Evans, J.B.; Quinlan, J.E. & Willard, J.E.
Partner: UNT Libraries Government Documents Department
open access

Thermodynamic Properties of Nonstoichiometric Nickel Tellurides and of Tellurium

Description: As part of a thermodynamic study of NiTe and NiTe/sub 2/, an attempt was made to gather data which would determine zero-point entropies as a function of composition. Part of the necessary data have been gathered, and in addition a number of other pertinent or interesting properties of the nickel tellurides, and of Te, have been investigated. Specific heats from 4 to 350 deg K have been measured on NiTe/sub 1.1/ NiTe/sub 1.5/, and NiTe/sub 2.0/, and the thermodynamic functions of these and all intermediate compositions may be considered accurately known over this temperature range. The method employed was conventional precise adiabatic calorimetry in an existing apparatus. The melting point of Te has been redetermined and the highly discordant literature critically reexamined; the triple point may now be stated with some confidence to be 449.7 plus or minus 0.2 deg C. The dissociation pressures of compositions from NiTe/sub 1.5/ to NiTe/ sub 2.0/ have been accurately measured at temperatures up to 780 deg C in order to determine the partial molal free energies and entropies of Te in these compounds. These measurements have incidentally elucidated the phase behavior in the Te-rich region, showing a high solubility of Ni in liquid Te at elevated temperatures, and incongruent melting of the solid solutions such that Te-rich solid solutions are unstable at elevated temperatures. By extrapolation, the boiling point of Te is computed to be 993.6 plus or minus 2 deg C. and the heat of vaporization to be 33,850-908 t cal/mole (one mole equals two gram-atoms). with an accuracy of plus or minus several hundred calories, from the triple point to t = 850 deg , or perhaps 950 deg C. This figure may be considered more accurate, though stated with less precision, than those of previous investigators. (auth)
Date: January 1, 1957
Creator: Machol, R. E.
Partner: UNT Libraries Government Documents Department
open access

A STUDY OF MECHANICAL-ELECTROLYTIC POLISHING ON URANIUM METALLOGRAPHIC SPECIMENS

Description: Proposed techniques for 'hot'' metallographic preparation are described. The following data from experiments on saw cutting, hand grinding, and electrolytic polishing have been obtained: radioactive contamination from saw cutting and grinding; depths of scratches and cold worked metal from saw cutting and grinding; metal removal rates for various grades of emery grinding papers; metal removal rates for electropolishing; optimum sequence for specimen grinding on emery papers; and time requirements for satisfactory electrolytic polishing of saw cut, rough ground, and fine ground uranium specimens. It has been shown that an efficient and effective procedure for preparation of saw cut uranium is the removal of about three-fourths of the cold worked layer with grade number 2 paper, followed by grades 3/0 and 4/0. The remaining fine scratches and thin layer of cold worked metal were removed by prolonged electropolishing in phosphoric acidethylene glycol-ethyl alcohol solution. (auth)
Date: January 1, 1957
Creator: Brown, F.L.
Partner: UNT Libraries Government Documents Department
open access

PHOTOELASTIC STUDY OF STRESS IN PERFORATED HEMISPHERICAL CLOSURES FOR A PRESSURE VESSEL. Research Report 100FF996-R1

Description: Photoelastic ''frozen stress'' tests were made of perforated hemispherical closures for a pressure vessel. Three different hole patterns were investigated. The ''circular'' and ''square'' arrangements of holes showed the highest peak stress, a value of stress + pressure of about 10 being noted in each. In comparison, the ''triangular'' arrangement of holes yielded a peak value of 8.20. (auth)
Date: January 1, 1957
Creator: Sampson, R.C. & Leven, M.M.
Partner: UNT Libraries Government Documents Department
open access

GRAPHITE-MODERATED, GRAPHITE-REFLECTED CRITICAL ASSEMBLIES

Description: Graphite-moderated, graphite reflected critical assemblies have been set up in the LASL Honeycomb remotely controlled machine. lnformation has been obtained on the critical masses of systems having C/Oy ratios of 6650 and 4093. A third system at a smaller ratio is planned. The reactivity contribution of channels through the core and reflector was determined. (auth)
Date: January 1, 1957
Creator: Byers, C.C.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen