48 research outputs found
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Argonne National Laboratory Reports
Report describing the research and development activities related to reactor fuels and fast-reactor programs conducted by the Argonne National Laboratory Chemical Engineering Division
Low-temperature properties of the heavy-fermion system U Cd
We present electrical-resistivity, magnetic-susceptibility, specific-heat, and thermal-expansion data for UCd11. The low-temperature specific heat indicates that the electronic subsystem has a highly enhanced specific heat which is partially removed by a phase transition at 5.0 K. © 1984 The American Physical Society
The influence of a relict distribution on genetic structure and variation in the Mediterranean tree, Platanus orientalis
The distribution of plant species around the Mediterranean basin is a product of the influence of both geographical barriers and of climatic changes experienced during the Tertiary, with the transition from a warm to cool periods. Several species, once largely distributed across the Northern Hemisphere, retracted to refugial areas in southern Europe where they are described as Tertiary relicts. Platanus orientalis is a typical representative of Tertiary flora in southwest Eurasia; its distribution spreads from the Caucasus to the Mediterranean, with its western border in Southern Italy and Sicily. We analysed genetic diversity and differentiation in the centre and western part of its distribution range using nuclear microsatellites and compared genetic parameters between core and western populations. We found an overall decrease in genetic diversity estimates (heterozygosity, private allelic richness) from central towards western populations, with those from Southern Italy and Sicily showing the lowest values. The low level of genetic diversity probably results from historic range fragmentation experienced by P. orientalis in its westernmost distribution as confirmed by high level genetic isolation of these populations. Ornamental hybrids were genetically distinguished from P. orientalis as contained private alleles, indicating that gene flow with natural populations is rare. Population assignment and neighbour-joining (NJ) analysis of populations identified four groups belonging to two main phyletic groups (the Southern Italian-Sicilian-Balkan and Cretan-Bulgarian-Turkish lineages) that seem to have different biogeographic origin and also excluded an artificial origin for southern Italian and Sicilian populations as previously suggested. These results show that quantifying the genetic variation of a Tertiary relict in a geographical context, and the potential effect of hybridization with introduced ornamental hybrids, can provide useful insights on factors influencing population genetic structure. Such information is crucial to predict how such taxa will respond to increasing anthropogenic influence on the environment
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Argonne National Laboratory Reports
Physicochemical and thermodynamic studies of liquid-lithium-containing systems have continued. Pressure-composition isotherms for the lithium-hydrogen system measured by a gravimetric technique are found to be in reasonably good agreement with earlier tensimetric results. Plateau-pressure studies of the lithium-hydrogen, lithium-deuterium, and lithium-tritium systems have been made at temperatures above and below the monotectic. The observed isotope effects were found to be near the predicted values. Measurements of the solubility of the lithium-deuterium in liquid lithium gave results in good agreement with prior data for the solubility of lithium-hydrogen in lithium and confirmed that the limits on cold trapping of lithium hydrides from lithium are too high for protected fusion reactor applications. Determination of the solubility of lithium dioxide in liquid lithium is nearing completion. Solubility values measured to date are slightly lower than, but in the range of, prior measurements
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Argonne National Laboratory Reports
Studies in basic energy science covered many different activities, nearly all of which were designed to gain information required for a better understanding of systems important to national needs in energy and environment. Studies of associating gases included measurements of thermal conductivities and basic molecular orbital calculations. Raman spectroscopy and spectrophotometry were used to determine thermodynamic and spectroscopic data on salt vapor complexes. Polarized Raman spectra of As2S3 thin films and vapors were recorded. Halogenation of lanthanide oxides with aluminum chloride allowed the separation of the resultant chloride complexes by vapor transport. Electrochemical titrations were used to obtain the solubility product of iron sulfide in molten LiCl-KCl eutectic. Solubility products of eleven sulfides in the same eutectic mixture were calculated. Galvanostatic techniques were used to study metal deposition/dissolution reactions in molten salts. Activity coefficients of lithium in lithium-lead alloys were determined electrochemically; phase diagrams of ternary alloys of Li-Al-Mg and Li-Ca-Mg were computed. Thermodynamic studies are being made of the sorption of hydrogen by Li-Al and Li-Pb alloys. The study of the solubility of oxygen in liquid lithium was completed. An electric resistance method for measuring distribution properties of nonmetallic elements in binary metallic systems containing lithium is being developed. Calorimetric methods were used to measure standard enthalpies of formation of some coal components, lanthanum and rare earth trifluorides, and gamma-UO3, UF6, Cs3CrO4, Cs4CrO4, As4S4, and As2S3. High-temperature enthalpy increments were measured for LaF3 and beta-As4S4. The acidities of airborne ammonium sulfate-bearing particles from various areas of the U.S. were measured using Fourier-transform infrared spectroscopy
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Chemical Engineering Division thermochemical studies. Annual report, July 1974--June 1975
Standard enthalpies of formation were determined for the following compounds: CsUO(c), -NaUO(c), BaUO(c), HI(aq), CsNO(c), CsCO(c), CsCl(c), RbCl(c), CsCrO(c), and CsCrO(c).Preliminary reaction calorimetric studies of WS and Li--Al alloys are described. High- temperature enthalpies and other thermodynamic properties are reported for - and -NaUO(c), CsUO(c), and AlO(c). (auth
Chemiluminescence in the oxidation of ionic organosodium compounds with naphthalene, anthracene, stilbene, and benzophenone in solution by oxygen
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Argonne National Laboratory Reports
The hydrogen permeabilities of selected metals, alloys, and multiplex preparations that are of interest to fusion reactor technology are being characterized. A high-vacuum hydrogen-permeation apparatus has been constructed for this purpose. A program of studies has been initiated to develop design details for the tritium-handling systems of near-term fusion reactors. This program has resulted in a better definition of reactor-fuel-cycle and enrichment requirements and has helped to identify major research and development problems in the tritium-handling area. The design and construction of a 50-gallon lithium-processing test loop (LPTL) is well under way. Studies in support of this project are providing important guidance in the selection of hardware for the LPTL and in the design of a molten-salt processing test section
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Argonne National Laboratory Reports
Standard enthalpies of formation at 298.15 K are reported for MgUO4, CaUO4, BaUO4, VF3, and PrF3 based on solution and fluorine bomb calorimetric measurements. High-temperature enthalpy increments have been determined for MgUO4 by drop calorimetry. Preliminary work on gamma -UO3 and beta-LiAl is described