نتایج جستجو برای: u3o8

تعداد نتایج: 69  

Journal: :Journal of Nuclear Materials 2023

Particle analysis is one of the key-techniques used in field nuclear safeguards. Beyond traditional uranium isotopy measurement, other methodologies are implemented to better characterize materials. Among them, age dating at particle scale enables determine time elapsed since last chemical step separation/purification or enrichment. The 230Th-234U couple being most common radiochronometer, ther...

Journal: :Minerals 2023

The Lower Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska hosts a high-grade uranium-thorium deposit with past production. complex is circular body (~3 km in diameter) which intruded Paleozoic granitoids as well metasedimentary and metavolcanic rocks the Alexander Terrane North American Cordillera. This shallow seated intrus...

Journal: :Environmental science & technology 2015
Olga N Batuk Steven D Conradson Olga N Aleksandrova Hakim Boukhalfa Boris E Burakov David L Clark Ken R Czerwinski Andrew R Felmy Juan S Lezama-Pacheco Stepan N Kalmykov Dean A Moore Boris F Myasoedov Donald T Reed Dallas D Reilly Robert C Roback Irina E Vlasova Samuel M Webb Marianne P Wilkerson

The speciation of U and Pu in soil and concrete from Rocky Flats and in particles from soils from Chernobyl, Hanford, Los Alamos, and McGuire Air Force Base and bottom sediments from Mayak was determined by a combination of X-ray absorption fine structure (XAFS) spectroscopy and X-ray fluorescence (XRF) element maps. These experiments identify four types of speciation that sometimes may and oth...

Journal: : 2021

Актуальность исследования обоснована целесообразностью создания благоприятных условий при проведении термохимической обработки топливных фрагментов с целью обеспечения одновременной трансформации керамического топлива в порошкообразный материал и полного высвобождения продукта реакции из оболочки, а также удаления топливной композиции перед гидрометаллургическими операциями летучих продуктов де...

Journal: :Economic Geology 2022

Abstract The Coles Hill uranium deposit, with an indicated resource of about 130 Mlb U3O8, is the largest unmined deposit in United States. hosted Taconian (approx. 480–450 Ma) Martinsville igneous complex, which consists Ordovician Leatherwood Granite (granodiorite) and Silurian Rich Acres Formation (diorite). host rock was metamorphosed to orthogneiss during Alleghanian orogeny 325–260 Ma), w...

2006
Giovanni La Macchia Marcin Brynda Laura Gagliardi

Use of sterically hindered ligands to maintain the integrity of normally unstable chemical entities is a widespread technique in modern synthetic chemistry. Bulky aryl and alkyl substituents have been designed to stabilize sensitive compounds, such as main-group-element dimers with multiple bonds, including the alkyne analogues of heavier Group 14 elements. 3] This methodology was recently empl...

2005
Stephen Croft Debbie Curtis Malcolm R. Wormald

Microsoft Excel spreadsheet functions have been developed for the calculation of the self attenuation of gamma-rays in simple bodies viewed from afar. The cases are a uniform rod viewed along its axis, a sphere viewed along a diameter and a cylinder (or disk) viewed along a mid-plane diameter. The results for the former two cases can be expressed in closed form while the algorithm used for the ...

2000
R. A. Guilmette M. D. Hoover G. J. Newton R. J. Howard R. N. Ortiz J. M. Thomas S. M. Trotter

The use of in vitro dissolution tests for estimating the in vivo solubility of inhaled radioactive aerosols is being increasingly considered for both prospective and retrospective exposure/dose assessments, mainly because such tests are relatively simple to conduct (compared to in vivo experiments) and because current respiratory tract dosimetry models (e.g., ICRP Publication 66, 1994) provide ...

2015
Celin Acharya

Uranium contamination is a worldwide problem. Preventing uranium contamination in the environment is quite challenging and requires a thorough understanding of the microbiological, ecological and biogeochemical features of the contaminated sites. Bioremediation of uranium is largely dependent on reducing its bioavailability in the environment. In situ bioremediation of uranium by microbial proc...

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