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Abstract
Japanese iron artifacts contain a small amount of charcoal which was used in manufacturing. We developed a wet method of carbon extraction from the iron samples for AMS radiocarbon dating. The method consists of dissolution of iron with a Cu2+ solution and dissolution of deposited Cu in HCl. High extraction yields (80–90%) and low contamination by modern carbon were achieved by the wet method.
Abstract
Prehistoric metal findings from Liguria are numerous, however, even though there were many metalliferous mines, the metal-working sites have not yet been ascertained.
This work discusses results on some metal objects from different archaeological sites in Liguria.
The objects examined were: 1) two melting drops 2) an axe, and 3) a knife. The physico-chemical investigation techniques employed were:
- - X-ray diffraction,
- - radiography,
- - microdrawing method, followed by optical and electron scanning microscopy observations,
- - differential thermal and thermogravimetric analyses to characterize the clay core found inside a socketed knife.
Abstract
A gas pressurized extraction chromatography (GPEC) system has been developed to perform elemental separations on radioactive samples to determine total and isotopic compositions of Cs and Ba from an irradiated salt sample, fuel sample and two sealed radiation sources. The GPEC system employs compressed nitrogen to move liquid through the system, compared to gravity or pumped liquids that are typically used for separations. A commercially available Sr-Resin™ was used to perform the separation for the above mentioned analytes. A 1% acetic acid solution was determined to be the best extractant for Ba. A flow rate of 0.1 mL/min was determined to be optimal for the separation of Ba. Complete recovery of the Cs and Ba was achieved, within the systematic uncertainties of the experiments.
Abstract
Microfluidic solvent extraction (microSX) of metal ions from industrial grade mineral leach solutions was studied. In conventional bulk-scale SX, partially hydrophobic nanoparticles that are present in the leach solution readily adsorb at the liquid-liquid interface of the dispersed droplets, causing delayed or incomplete phase separation and reduce efficiency. In contrast, microSX employs continuous microscopic streams of aqueous and organic phases (without mixing the phases) and, in this way, bypasses the need for a conventional phase separation stage. This makes the technique promising for handling complex leach solutions. The stability of the two-phase flow is considered in terms of the surface wettability and guiding geometry of the microchannel, which determines the Laplace pressure window that stabilizes the liquid-liquid interface. We show that careful characterization of the microchannel wettability, including contact angle hysteresis, is essential to predict long-term flow stability.
formed by microbial decarboxylation and transamination of amino acids to aldehydes or ketones. During ageing or possible degradation, if the reaction conditions are favourable in terms of enzyme activity, the growth of microorganisms leads to the
Abstract
Assessment of the long-term performance of nuclear melt glass under saturated conditions provides insight into factors controlling radionuclide release into groundwater. Melt glass samples were collected from an underground nuclear detonation cavity at the Nevada Test Site that was in contact with groundwater for more than 10 years. The samples were made into thin sections and the distribution of alpha-activity mapped using CR-39 plastic detectors. The melt glass is visually heterogeneous and the results of the alpha-track radiography indicate that the highest alpha-activity is associated with areas of dark colored glass. Analyses of the thin sections by alpha-spectrometry show the prominent actinide species to be 238Pu, 239,240Pu and 241Am. Scanning electron microprobe analysis of the bulk glass shows conspicuous alteration layers lining internal vesicle surfaces in the glass. X-ray diffraction patterns for the alteration phases are consistent with clay mineral compositions. Glass dissolution models indicate these layers are too thick to have formed at ambient temperatures over the 10 year period in which they remained in a saturated environment. This implies the alteration layers likely formed at temperatures higher than ambient during cooling of the cavity following the underground detonation. Mobilization of this clay alteration layer as colloidal particles in groundwater represents a potential source of actinide release into the environment.
