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- Magnusson, Daniel, 1978, et al.
(författare)
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Demonstration of a SANEX process in centrifugal contactors using the CyMe4-BTBP molecule on a genuine fuel solution
- 2009
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 27:2, s. 97-106
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Tidskriftsartikel (refereegranskat)abstract
- Efficient recovery of minor actinides from a genuine spent fuel solution has been successfully demonstrated by the CyMe4-BTBP/DMDOHEMA extractant mixture dissolved in octanol. The continuous countercurrent process, in which actinides(III) were separated from lanthanides(III), was carried out in laboratory centrifugal contactors using an optimized flow-sheet involving a total of 16 stages. The process was divided into 9 stages for extraction from a 2 M nitric acid feed solution, 3 stages for lanthanide scrubbing, and 4 stages for actinide back-extraction. Excellent feed decontamination factors for Am (7000) and Cm (1000) were obtained and the recoveries of these elements were higher than 99.9%. More than 99.9% of the lanthanides were directed to the raffinate except Gd for which 0.32% was recovered in the product.
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- Magnusson, Daniel, 1978, et al.
(författare)
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Demonstration of a TODGA based Extraction Process for the Partitioning of Minor Actinides from a PUREX Raffinate
- 2009
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 27:1, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Efficient recovery of minor actinides (MA) from genuine PUREX raffinate has been successfully demonstrated by the TODGA + TBP extractant mixture dissolved in an industrial aliphatic solvent TPH. The process was carried out in centrifugal contactors using an optimized flow-sheet involving a total of 32 stages, divided into 4 stages for extraction, 12 stages for scrubbing and 16 stages for back-extraction. Very high feed decontamination factors were obtained (Am, Cm 40 000) and the recovery of these elements was higher than 99.99%. Of the non-lanthanide fission products only Y and a small part of Ru were co-separated into the product fraction together with the lanthanides and the MA.
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- Magnusson, Daniel, 1978, et al.
(författare)
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Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors
- 2009
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Ingår i: Radiochimica Acta. - : Walter de Gruyter GmbH. - 0033-8230. ; 97:3, s. 155-159
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Tidskriftsartikel (refereegranskat)abstract
- The design of an efficient process flow-sheet requires accurate extraction data for experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe4-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. the results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed.
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- Maxwell, Karen L., et al.
(författare)
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Protein folding : Defining a "standard" set of experimental conditions and a preliminary kinetic data set of two-state proteins
- 2005
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Ingår i: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 14, s. 602-16
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Tidskriftsartikel (refereegranskat)abstract
- Recent years have seen the publication of both empirical and theoretical relationships predicting the rates with which proteins fold. Our ability to test and refine these relationships has been limited, however, by a variety of difficulties associated with the comparison of folding and unfolding rates, thermodynamics, and structure across diverse sets of proteins. These difficulties include the wide, potentially confounding range of experimental conditions and methods employed to date and the difficulty of obtaining correct and complete sequence and structural details for the characterized constructs. The lack of a single approach to data analysis and error estimation, or even of a common set of units and reporting standards, further hinders comparative studies of folding. In an effort to overcome these problems, we define here a "consensus" set of experimental conditions (25°C at pH 7.0, 50 mM buffer), data analysis methods, and data reporting standards that we hope will provide a benchmark for experimental studies. We take the first step in this initiative by describing the folding kinetics of 30 apparently two-state proteins or protein domains under the consensus conditions. The goal of our efforts is to set uniform standards for the experimental community and to initiate an accumulating, self-consistent data set that will aid ongoing efforts to understand the folding process.
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