5,091 research outputs found

    Effect of weathering product assemblages on Pb bioaccessibility in mine waste: implications for risk management

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    General assessments of orebody types and associated mine wastes with regards to their environmental signature and human health hazards are needed to help managing present and historical mine waste facilities. Bioaccessibility tests and mineralogical analysis were carried out on mine waste from a systematic sampling of mine sites from the Central Wales orefield, UK. The bioaccessible Pb widely ranged from 270 to 20300 mg/kg (mean 7250 mg/kg; median 4890 mg/kg) and the bioaccessible fraction from 4.53 % to >100 % (mean 33.2 %; median 32.2 %), with significant (p=0.001) differences among the mine sites. This implies sensitivity of bioaccessibility to site-specific conditions and suggests caution in the use of models to assess human health impacts generalised on the basis of the mineral deposit type. Mineralogical similarities of the oxidation products of primary galena provided a better control over the observed Pb bioaccessibility range. The higher Pb bioaccessibility (%) was related to samples containing cerussite, irrespective of the presence of other Pb minerals in the mineral assemblage; lower Pb bioaccessibility resulted where anglesite was the main Pb mineral phase and cerussite was absent. A solubility diagram for the various Pb minerals in the waste was derived using PHREEQC model and the experimental Pb concentration measured in the simulated gastric solution compared with the equilibrium modelling results. For samples containing cerussite, the model well predicted the soluble Pb concentrations measured in the experimental simulated gastric solution, indicative of the carbonate mineral phase control on the Pb in solution for these samples and little kinetic control on the dissolution of cerussite. On the contrary, most mine waste samples containing dominant anglesite and or plumbojarosite (no cerussite) had lower solution Pb values, falling at or below the anglesite and plumbojarosite solubility equilibrium concentrations, implying kinetic or textural factors hindering the dissolution

    Authority in the Virtual Sangat : Sikhism, Ritual and Identity in the Twenty-First Century

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    In her paper Authority in the Virtual Sanga. Sikhism, Ritual and Identity in the Twenty-First Century, Doris Jakobsh analyses the change of authority based on her research on Sikhs on the Internet. She stresses the Web as a ‘third place’ of communication among the Sikhs as well as the phenomenon of new authorities online. However, this does not imply the replacement of the traditional seats of authority, the Akal Takht, SGPC, or gurdwara managements, but one can recognize a significant shift away from these traditional sites of authority toward the ‘new authorities’, the intermediaries of cyberspace. Her analysis shows that this aspect of the Sikh experience brings with it the most profound challenges and, most importantly, a need to bridge the post-modern individual, i.e. ‘Sikh tradition’ intertwined and legitimated by the metanarrative, and the proliferation of new authorities who have become intermediaries of Sikhism online by virtue of their expertise within the digital domain

    Electron capture to continuum in collisions of bare projectiles with Ne targets

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    Abstract. We have investigated the cusp resulting from electron capture to the continuum of 1.25-5 MeV m u- ' fully stripped hydrogen and oxygen as a function of the collision energy and the detector angular resolution B o. It is revealed that the characteristic cusp shape parameters depend strongly on the experimental resolution. Our experimental data are "pared with the second-order Born theory and the impulse approximation. Both theories mnhrm the 8, dependence of the shape parameters and gjve a reasonable descrip-lion of the cusp asymmetry. However, theory tends to overestimate the absolute cross sections, in particular in the case of oxygen. 1

    The Use of Copyright Law to Block the Importation of Gray-Market Goods: The Black and White of It All

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    Procedural Rules -- Emergency -- Judge\u27s Discretion

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    Alien Registration- Macgorman, Doris R. (Caribou, Aroostook County)

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    https://digitalmaine.com/alien_docs/26169/thumbnail.jp
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