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1

SEPARATION OF URANIUM AND THORIUM  

Microsoft Academic Search

A simple and direct ion-exchange method has been suggested for the ; separation of uranium from thorium. Both the elements are absorbed by the resin ; (Amberlite lR) from which uranium can be eluted first with 1.70 M hydrochloric ; acid. After neutralizing the acid by running ammonia solution through the resin ; column, thorium is eluted with l.1 M

S. V. Suryanarayana; Bh. S. V. R. RaO

1958-01-01

2

Method for the Separation of Uranium Isotopes.  

National Technical Information Service (NTIS)

A method for the separation of uranium isotopes, particularly U235 is disclosed. The method employs a frequency selective laser irradiation of an adiabatically cooled beam of UF6 molecules, followed by the 'chemionization' i.e., SbF5 + UF6 SbF6(-) + UF5(+...

A. Auerbach

1980-01-01

3

The use of selective extraction chromatographic columns as an alternative to solvent extraction for the separation of uranium followed by the use of Arsenazo III as a calorimetric reagent for uranium determination  

SciTech Connect

The use of U/TEVA{reg_sign} Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA{reg_sign} Spec columns have several advantages over the widely used 4-methyl-2-pentanone solvent extraction method. Among the advantages are: (1) no hazardous liquid organic waste, that creates regulatory waste disposal problems, is generated; (2) a clean separation of U from Zr, F, and fission products is obtained; (3) the sample preparation time is reduced; and (4) the exposure of analysts to ionizing radiation is reduced because the entire procedure may be performed in a hot cell using remote operations. This study also investigated the use of Arsenazo III (1,8-dihydroxynapthalene-3,6-disulfonic acid-2,7-bis [<-azo-2>-phenylarsonic acid]) as a calorimetric reagent to determine uranium concentrations over a wide range in waste streams and product streams at the Idaho Chemical Processing Plant. Process and waste stream samples were passed through a U/TEVA{reg_sign} Spec column to selectively remove the uranium. The uranium bearing fraction is compatible with the pH range for color development with Arsenazo III. Arsenazo III may be added to the uranium fraction, at a 3:1 mole ratio (Arsenazo:Uranium) at the high end of the method (10 {mu}/mL). Arsenazo III forms a highly stable complex with uranium. Stability tests from this and other studies show that the colored complex of Arsenazo III with U(VI) forms within one minute and remains stable for several hours. The complex with U(VI) varies in color with pH. However, with excess reagent, the color is varying shades of purple. Since the samples were passed through a highly selective extraction chromatographic column prior to adding the calorimetric reagent, no interferences were observed.

Miller, C.J.; Del Mastro, J.R.

1994-10-01

4

Separation of uranium on polyurethane foam impregnated with trioctylphosphine oxide  

SciTech Connect

A method is described for the quantitative separation of uranium from practically all other elements in 1M hydrochloric acid solution containing ascorbic acid. From such a solution uranium is retained selectively by a column containing open-cell polyurethane foam impregnated with tri-n-octylphosphine oxide (TOPO). The uranium together with TOPO is eluted with ethanol and then it is adsorbed on a column of Dowex 1 anion exchange resin from a HCl-organic solvent system. Uranium is eluted with 1M hydrochloric acid. 5 tables.

Korkisch, J.; Steffan, I.

1983-01-01

5

Thermodynamical estimation of the processes involved in the separation of uranium and plutonium hexafluorides by selective chemical reducing agents  

Microsoft Academic Search

The processes involved in the separation of UF6-PuF 6 mixtures are of considerable interest in connection with the technology of processing the nuclear fuel of breeder reactors by the fluoride volatility method. The separation is based on the differing physical and chemical properties of the hexafluorides. There are three methods of separation which have been most widely discussed: distillation, thermal

N. P. Galkin; V. T. Orekhov; A. G. Rybakov

1973-01-01

6

SELECTIVE DISSOLUTION OF URANIUM IN URANIUM-URANIUM OXIDE MIXTURES  

Microsoft Academic Search

An 8 N solution of Br in ethyl acetate selectively dissolves U metal, ; leaving uranium oxides unattacked. Interfering acids produced by side reactions ; of Br with the solvent are neutralized by MgO, permitting the dissolution period ; to be extended. (auth);

G. F. Brunzie; T. R. Johnson; R. K. Steunenberg

1961-01-01

7

SEPARATION OF PLUTONIUM FROM URANIUM  

Microsoft Academic Search

A three-column extraction process using tributyl phosphate is outlined ; for the effective separation of Pu from irradiated U. Means is provided for ; delaying the flow of solvent extractant to permit the Pu dibutyl phosphate ; complex to be converted into the tributyl phosphate complex for easier stripping ; from the solvent. (D.L.C.)

W. W. morgan; W. G. Mathers; R. G. Hart

1963-01-01

8

Use of selective extraction chromatographic columns as an alternative to solvent extraction for the separation of uranium followed by the use of Arsenazo III as a colorimetric reagent for uranium determination.  

National Technical Information Service (NTIS)

The use of U/TEVA(reg sign) Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA(reg sign) Spec colu...

C. J. Miller J. R. Del Mastro

1994-01-01

9

Tributyl-phosphate-impregnated sorbents for plutonium-uranium separations  

SciTech Connect

Bayer AG Lewatit OC-1023, a macroporous sorbent impregnated with tributyl phosphate (TBP), was evaluated for the separation of uranium and plutonium from mixed actinide residues. The sorbent was tested for uranium breakthrough capacity, plutonium washing, and uranium elution behavior. TBP-impregnated Amberlite XAD-4 was compared to the Lewatit OC-1023.

Alford, C.E.; Navratil, J.D.

1986-03-24

10

Separation of Uranium Isotopes by Gas Centrifugation.  

National Technical Information Service (NTIS)

The uranium isotope enrichment is studied by means of the countercurrent gas centrifuge driven by thermal convection. A description is given of (a) the transfer and purification of the uranium hexafluoride used as process gas in the present investigation;...

I. Jordan

1980-01-01

11

Uranium isotope separation from 1941 to the present  

Microsoft Academic Search

Uranium isotope separation was the key development for the preparation of highly enriched isotopes in general and thus became the seed for target development and preparation for nuclear and applied physics.In 1941 (year of birth of the author) large-scale development for uranium isotope separation was started after the US authorities were warned that NAZI Germany had started its program for

Peter Maier-Komor

2010-01-01

12

Innovative lasers for uranium isotope separation. [Progress report  

Microsoft Academic Search

Copper vapor lasers have important applications to uranium atomic vapor laser isotope separation (AVLIS). The authors have spent the first two years of their project investigating two innovative methods of exciting\\/pumping copper vapor lasers which have the potential to improve the efficiency and scaling of large laser systems used in uranium isotope separation. Experimental research has focused on the laser

M. L. Brake; R. M. Gilgenbach

1991-01-01

13

New separation process for neptunium, plutonium, and uranium using butyraldehydes as reductants in reprocessing  

Microsoft Academic Search

A new neptunium, plutonium, and uranium separation process using n- and iso-butyraldehydes as reductants for Np(VI) and Pu(IV), respectively, is described for nuclear fuel reprocessing. A kinetics study and a chemical flow sheet study are conducted to develop the selective separation process for neptunium, plutonium, and uranium. In the kinetics study, it is found that n-butyraldehyde reduces Np(VI) to Np(V)

Gunzo Uchiyama; Sachio Fujine; Shinobu Hotoku; Mitsuru Maeda

1993-01-01

14

Uranium Metal Analysis via Selective Dissolution  

SciTech Connect

Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Chenault, Jeffrey W.

2008-09-10

15

METHOD OF SEPARATING FISSION PRODUCTS FROM FUSED BISMUTH-CONTAINING URANIUM  

Microsoft Academic Search

A process is described for removing metal selectively from liquid metal ; compositions. The method effects separation of flssion product metals ; selectively from dilute solution in fused bismuth, which contains uraniunn in ; solution without removal of more than 1% of the uranium. The process comprises ; contacting the fused bismuth with a fused salt composition consisting of sodium,

Wiswall

1958-01-01

16

Uranium\\/plutonium and uranium\\/neptunium separation by the Purex process using hydroxyurea  

Microsoft Academic Search

Hydroxyurea dissolved in nitric acid can strip plutonium and neptunium from tri-butyl phosphate efficiently and has little\\u000a influence on the uranium distribution between the two phases. Simulating the 1B contactor of the Purex process by hydroxyurea\\u000a with nitric acid solution as a stripping agent, the separation factors of uranium\\/plutonium and uranium\\/neptunium can reach\\u000a values as high as 4.7. 104 and

Zhu Zhaowu; He Jianyu; Zhang Zefu; Zhang Yu; Zhu Jianmin; Zhen Weifang

2004-01-01

17

Uranium\\/plutonium and uranium\\/neptunium separation by the Purex process using hydroxyurea  

Microsoft Academic Search

Hydroxyurea dissolved in nitric acid can strip plutonium and neptunium from tri-butyl phosphate efficiently and has little influence on the uranium distribution between the two phases. Simulating the 1B contactor of the Purex process by hydroxyurea with nitric acid solution as a stripping agent, the separation factors of uranium\\/plutonium and uranium\\/neptunium can reach values as high as 4.7·104 and 260,

Zhu Zhaowu; He Jianyu; Zhang Zefu; Zhang Yu; Zhu Jianmin; Zhen Weifang

2004-01-01

18

Pulsed CO laser for isotope separation of uranium  

SciTech Connect

This article proposes a technical solution for using a CO laser facility for the industrial separation of uranium used in the production of fuel for nuclear power plants, employing a method of laser isotope separation of uranium with condensation repression in a free jet. The laser operation with nanosecond pulse irradiation can provide an acceptable efficiency in the separating unit and a high efficiency of the laser with the wavelength of 5.3 {mu}m. In the present work we also introduce a calculation model and define the parameters of a mode-locked CO laser with a RF discharge in the supersonic stream. The average pulsed CO laser power of 3 kW is sufficient for efficient industrial isotope separation of uranium in one stage.

Baranov, Igor Y.; Koptev, Andrey V. [Rocket-Space Technics Department, Baltic State Technical University, 1, 1st Krasnoarmeyskaya st.,St. Petersburg, 190005 (Russian Federation)

2012-07-30

19

Uranium isotope separation from 1941 to the present  

NASA Astrophysics Data System (ADS)

Uranium isotope separation was the key development for the preparation of highly enriched isotopes in general and thus became the seed for target development and preparation for nuclear and applied physics. In 1941 (year of birth of the author) large-scale development for uranium isotope separation was started after the US authorities were warned that NAZI Germany had started its program for enrichment of uranium and might have confiscated all uranium and uranium mines in their sphere of influence. Within the framework of the Manhattan Projects the first electromagnetic mass separators (Calutrons) were installed and further developed for high throughput. The military aim of the Navy Department was to develop nuclear propulsion for submarines with practically unlimited range. Parallel to this the army worked on the development of the atomic bomb. Also in 1941 plutonium was discovered and the production of 239Pu was included into the atomic bomb program. 235U enrichment starting with natural uranium was performed in two steps with different techniques of mass separation in Oak Ridge. The first step was gas diffusion which was limited to low enrichment. The second step for high enrichment was performed with electromagnetic mass spectrometers (Calutrons). The theory for the much more effective enrichment with centrifugal separation was developed also during the Second World War, but technical problems e.g. development of high speed ball and needle bearings could not be solved before the end of the war. Spying accelerated the development of uranium separation in the Soviet Union, but also later in China, India, Pakistan, Iran and Iraq. In this paper, the physical and chemical procedures are outlined which lead to the success of the project. Some security aspects and Non-Proliferation measures are discussed.

Maier-Komor, Peter

2010-02-01

20

SEPARATION OF URANIUM FROM THORIUM BY LIQUID METAL EXTRACTION THORIUM RECOVERY AND FISSION PRODUCT DISTRIBUTION  

Microsoft Academic Search

Additional results were obtained on the small-scale separation of ; uranium from thorium by molten magnesium extraction. This process is aimed at ; the separation and recovery of uranium and thorium from a thorium breeder blanket. ; On dissolution of a thorium-uranium alloy in molten magnesium, 90 to 95% of the ; uranium introduced was recovered as a uranium -thorium

J. D. Chilton; L. A. Hanson; E. W. Murbach; F. W. Dodge

1962-01-01

21

Separation of heavy metals from aqueous solutions using biosorbents: development of contacting devices for uranium removal  

SciTech Connect

The specific objective of the work described herein was to evaluate the utility of a mixed culture of denitrifying bacteria for the separation of uranium from process wastewaters. The selection of this culture was based upon the knowledge that wastewaters generated in a number of nuclear-materials processing operations require treatment to remove both nitrate and uranium. It was anticipated that microbial cells, resulting as a by-product in the conversion of nitrate to gaseous molecular nitrogen, might serve as an effective biosorbent for the separation of uranium from the wastewaters. The culture was evaluated with respect to the rate of uranium accumulation and the equilibrium distribution of uranium between the cell and solvent phases. The effects of process variables on the rate of uranium accumulation and equilibrium distribution were studied. Several methods for contacting the biosorbent with aqueous uranium solutions were examined. These included suspended cells or flocs in stirred-tank reactors and films of cells or inert particles in columnar reactors.

Shumate, S.E. II; Strandberg, G.W.; McWhirter, D.A.; Parrott, J.R. Jr.; Bogacki, G.M.; Locke, B.R.

1980-01-01

22

Bio-/Photo-Chemical Separation and Recovery of Uranium  

SciTech Connect

Citric acid forms bidentate, tridentate, binuclear or polynuclear species with transition metals and actinides. Biodegradation of metal citrate complexes is influenced by the type of complex formed with metal ions. While bidentate complexes are readily biodegraded, tridentate, binuclear and polynuclear species are recalcitrant. Likewise certain transition metals and actinides are photochemically active in the presence of organic acids. Although the uranyl citrate complex is not biodegraded, in the presence of visible light it undergoes photochemical oxidation/reduction reactions which result in the precipitation of uranium as UO{sub 3} {center_dot} H{sub 2}O. Consequently, we developed a process where uranium is extracted from contaminated soils and wastes by citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, whereas uranyl citrate which is recalcitrant remains in solution. Photochemical degradation of the uranium citrate complex resulted in the precipitation of uranium. Thus the toxic metals and uranium in mixed waste are recovered in separate fractions for recycling or for disposal. The use of naturally-occurring compounds and the combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in cost.

Francis,A.J.; Dodge, C.J.

2008-03-12

23

Separation of uranium and dibutyl phosphate contained in 30 vol % tributyl phosphate solvents  

Microsoft Academic Search

A number of solid sorbents were tested for the removal of uranium and dibutyl phosphate (DBP) from 30 vol % tributyl phosphate (TBP) solvent. The removal was required to result in separation of the uranium from the DBP with a clean uranium product. The preferred mode of operation was to remove the DBP, leaving the uranium in the cleaned solvent

J. C. Mailen; O. K. Tallent

1986-01-01

24

Uranium Metal Analysis via Selective Dissolution  

Microsoft Academic Search

Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation\\/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this

Calvin H. Delegard; Sergey I. Sinkov; Andrew J. Schmidt; Jeffrey W. Chenault

2008-01-01

25

Innovative lasers for uranium isotope separation. [Progress report  

SciTech Connect

Copper vapor lasers have important applications to uranium atomic vapor laser isotope separation (AVLIS). The authors have spent the first two years of their project investigating two innovative methods of exciting/pumping copper vapor lasers which have the potential to improve the efficiency and scaling of large laser systems used in uranium isotope separation. Experimental research has focused on the laser discharge kinetics of (1) microwave, and (2) electron beam excitation/pumping of large-volume copper vapor lasers. During the first year, the experiments have been designed and constructed and initial data has been taken. During the second year these experiments have been diagnosed. Highlights of some of the second year results as well as plans for the future include the following: Microwave resonant cavity produced copper vapor plasmas at 2.45 GHz, have been investigated. A CW (0--500 W) signal heats and vaporizes the copper chloride to provide the atomic copper vapor. A pulsed (5 kW, 0.5--5kHz) signal is added to the incoming CW signal via a hybrid mixer to excite the copper states to the laser levels. An enhancement of the visible radiation has been observed during the pulsed pardon of the signal. Electrical probe measurements have been implemented on the system to verify the results of the electromagnetic model formulated last year. Laser gain measurements have been initiated with the use of a commercial copper vapor laser. Measurements of the spatial profile of the emission are also currently being made. The authors plan to increase the amount of pulsed microwave power to the system by implementing a high power magnetron. A laser cavity will be designed and added to this system.

Brake, M.L.; Gilgenbach, R.M.

1991-06-01

26

Method of separating and recovering uranium and related cations from spent Purex-type systems  

DOEpatents

A process for separating uranium and related cations from a spent Purex-type solvent extraction system which contains degradation complexes of tributylphosphate wherein the system is subjected to an ion-exchange process prior to a sodium carbonate scrubbing step. A further embodiment comprises recovery of the separated uranium and related cations. 5 figs.

Mailen, J.C.; Tallent, O.K.

1987-02-25

27

Uranium Metal Analysis via Selective Dissolution.  

National Technical Information Service (NTIS)

Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorou...

A. J. Schmidt C. H. Delegard J. W. Chenault S. D. Sinkov

2008-01-01

28

Uranium isotope separation in the solid state. Final report for period ending September 30, 1978  

SciTech Connect

The final results of an investigation on the isotope separation of uranium in the solid state are presented in this report. The feasibility of separating uranium isotopes using the proposed system based on uranium borohydride (borodeuteride) in a low temperature mixed crystal has been determined. The first section of the report summarizes the background material relating to this work which includes: a calculation of isotope shifts (borodeuteride), details on the two-step, two-photon spectroscopic isotope separation technique, and a brief overview of the method and equipment used for separating uranium isotopes in the solid state. The second section concerns the experimental details of the present work performed in the laboratory. Representative spectroscopic data obtained in this investigation are presented and discussed in the third section. Finally, the report is concluded with recommendations for further investigations on the uranium borohydride (borodeuteride) system for isotope separation.

Bernstein, E.R.

1978-09-01

29

Separation of uranium using microcapsule of Tri-N-octylphosphine oxide  

SciTech Connect

A tri-n-octylphosphine oxide (TOPO) microcapsule has been developed for separating uranium from sulfuric acid solutions that have been used to decontaminate uranium waste. The distribution coefficient of the uranium was about 100 ml/g for a sulfuric acid concentration of 0.1-1.0 mol/L. The separation factor for uranium from iron, a representative metal dissolved in waste solution, was about 1000. A 1 g of TOPO microcapsule can remove uranium from about 50 mL of waste solution. The spent microcapsule easily decomposed when heated to about 300- 500 deg. C completely decomposed when heated to 300 deg. C. This TOPO microcapsule is thus well suited for volume reduction of uranium-bearing waste. (authors)

Kamoshida, M.; Iwamoto, T.; Fukasawa, T. [Hitachi, Ltd., Omika, Hitachi, Ibraki (Japan); Mimura, H. [Tohoku Univ., Sendai (Japan)

2007-07-01

30

Separation of uranium from technetium in recovery of spent nuclear fuel  

DOEpatents

Uranium and technetium in the product stream of the Purex process for recovery of uranium in spent nuclear fuel are separated by (1) contacting the aqueous Purex product stream with hydrazine to reduce Tc.sup.+7 therein to a reduced species, and (2) contacting said aqueous stream with an organic phase containing tributyl phosphate and an organic diluent to extract uranium from said aqueous stream into said organic phase.

Pruett, David J. (Knoxville, TN); McTaggart, Donald R. (Knoxville, TN)

1984-01-01

31

Separation of uranium from technetium in recovery of spent nuclear fuel  

DOEpatents

Uranium and technetium in the product stream of the Purex process for recovery of uranium in spent nuclear fuel are separated by (1) contacting the aqueous Purex product stream with hydrazine to reduce Tc/sup +7/ therein to a reduced species, and (2) contacting said aqueous stream with an organic phase containing tributyl phosphate and an organic diluent to extract uranium from said aqueous stream into said organic phase.

Pruett, D.J.; McTaggart, D.R.

1983-08-31

32

Isotope Separation of Uranium by Laser: Tuning and Frequency Instability.  

National Technical Information Service (NTIS)

Intensity measurements of laser induced fluorescence in an uranium atomic beam are affected by the axial mode structure of the commercial pulsed dye laser used and by its strong frequency instability. Qualitative and quantitative evaluations on the possib...

M. Broglia M. Massimi U. Spoglia P. Zampetti P. Benetti

1983-01-01

33

Separation of Uranium by an Extractant Encapsulated Magnetic Alginate Gels  

NASA Astrophysics Data System (ADS)

The aim of this work is to prepare environmentally friendly and practically applicable alginate magnetic biopolymers encapsulated tri-n-butyl phosphate (TBP) for the removal uranium ions. Some important process parameters such as initial pH, initial U(VI) concentration, adsorbent dosage, time, temperature and sorption isotherms for uranium uptake were studied and the thermodynamic parameters for U(VI) were determined.

Portakal, Z.; Gok, C.; Aytas, S.

34

Separation of uranium and dibutyl phosphate contained in 30 vol % tributyl phosphate solvents  

SciTech Connect

A number of solid sorbents were tested for the removal of uranium and dibutyl phosphate (DBP) from 30 vol % tributyl phosphate (TBP) solvent. The removal was required to result in separation of the uranium from the DBP with a clean uranium product. The preferred mode of operation was to remove the DBP, leaving the uranium in the cleaned solvent for recycle. A method for removal of DBP from the solvent while allowing the uranium to remain in the solvent was not found. Both cation resins and diethylene triamine pentaacetic acid (DTPA) deposited on glass beads preferentially removed the uranium, leaving the DBP in the solvent. The DBP could then be readily removed by a number of simple treatments, and the uranium could be recovered by elution with acidified TBP. Both hydroxide-form, anion-exchange resins and activated alumina (used with dry solvent) removed uranium and DBP. It is possible that the DBP and uranium could be separately eluted from these sorbents, but it was not successfully tested. 4 refs., 17 figs., 1 tab.

Mailen, J.C.; Tallent, O.K.

1986-07-01

35

Status of Uranium Atomic Vapor Laser Isotope Separation Program  

SciTech Connect

This report discusses demonstrations of plant-scale hardware embodying AVLIS technology which were completed in 1992. These demonstrations, designed to provide key economic and technical bases for plant deployment, produced significant quantities of low enriched uranium which could be used for civilian power reactor fuel. We are working with industry to address the integration of AVLIS into the fuel cycle. To prepare for deployment, a conceptual design and cost estimate for a uranium enrichment plant were also completed. The U-AVLIS technology is ready for commercialization.

Chen, Hao-Lin; Feinberg, R.M.

1993-06-01

36

Protein Separation via Polyelectrolyte Coacervation: Selectivity and Efficiency  

Microsoft Academic Search

Selective phase separation with polyelectrolytes can be used to separate a mixture of proteins. The efficiency of separation was examined using the cationic polyelectrolyte poly(diallyldimethylammonium chloride) and the model proteins bovine serum albumin, ‚-lactoglobulin, Á-globulin, and ribonuclease A. The coacervation yield for individual proteins and the degree of separation, for selected protein pairs, were studied as a function of polymer

Ying-fan Wang; Jeff Y. Gao; Paul L. Dubin

1996-01-01

37

Selection and microstructures of high density uranium alloys  

SciTech Connect

Twelve uranium alloys have been selected for incorporation into very high density aluminum dispersion fuel plates for irradiation testing. These alloys are (nominally) U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-2Mo-1Nb-1Zr, U-6Mo-1Pt, U-6Mo-0.6Ru, U-6Mo-0.6Si, and U-10Mo-0.05Sn. The rationale for selection of these fuels based on gamma phase stability, reports of good irradiation performance, and high uranium density will be discussed. The microstructures of these fuels were examined by SEM/EDS and XRD at three storage during the powder fabrication process. Microstructures of selected alloys are discussed.

Meyer, M.K.; Trybus, C.L.; Hofman, G.L.; Frank, S.M.; Wiencek, T.C.

1997-10-01

38

Extraction-chromatographic separation of uranium from long-lived fission products using tributyl phosphate  

Microsoft Academic Search

Extraction-chromatographic separation of uranium from fission products was performed using undiluted tributyl phosphate sorbed\\u000a on Chromosorb W as a stationary phase, and nitric acid (1: 3) as a mobile phase. Most of the fission products that contributed\\u000a greatly to the radiation level of the sample passed through the column; this effected considerable decontamination. Uranium\\u000a retained on the column was quantitatively

N. Tamura; C. Yonezawa

1974-01-01

39

Separation of uranium from technetium in recovery of spent nuclear fuel  

DOEpatents

A method for decontaminating uranium product from the Purex process comprises addition of hydrazine to the product uranyl nitrate stream from the Purex process, which contains hexavalent (UO.sub.2.sup.2+) uranium and heptavalent technetium (TcO.sub.4 -). Technetium in the product stream is reduced and then complexed by the addition of oxalic acid (H.sub.2 C.sub.2 O.sub.4), and the Tc-oxalate complex is readily separated from the uranium by solvent extraction with 30 vol. % tributyl phosphate in n-dodecane.

Friedman, Horace A. (Oak Ridge, TN) [Oak Ridge, TN

1985-01-01

40

Separation of uranium from technetium in recovery of spent nuclear fuel  

DOEpatents

A method for decontaminating uranium product from the Purex 5 process comprises addition of hydrazine to the product uranyl nitrate stream from the Purex process, which contains hexavalent (UO/sub 2//sup 2 +/) uranium and heptavalent technetium (TcO/sub 4/-). Technetium in the product stream is reduced and then complexed by the addition of oxalic acid (H/sub 2/C/sub 2/O/sub 4/), and the Tc-oxalate complex is readily separated from the 10 uranium by solvent extraction with 30 vol % tributyl phosphate in n-dodecane.

Friedman, H.A.

1984-06-13

41

Separation of uranium from technetium in recovery of spent nuclear fuel  

NASA Astrophysics Data System (ADS)

A method for decontaminating uranium product from the Purex 5 process is described. Hydrazine is added to the product uranyl nitrate stream from the Purex process, which contains hexavalent (UO2(2+)) uranium and heptavalent technetius (TcO4-). Technetium in the product stream is reduced and then complexed by the addition of oxalic acid (H2O2O4), and the Tc-oxalate complex is readily separated from the 10 uranium by solvent extraction with 30 vol % tributyl phosphate in n-dodecane.

Friedman, H. A.

1984-06-01

42

Ion separation by selective crystallization of organic frameworks  

SciTech Connect

Selective crystallization of organic frameworks is presented as a promising alternative to ion separation from competitive aqueous environments. The review focuses primarily on the principles determining ion selectivity in crystallization, as well as on structure-selectivity relationships. Specific examples involving anion separation by selective crystallization are discussed.

Custelcean, Radu [ORNL

2009-01-01

43

Separation of tc from Uranium and development of metallic Technetium waste forms  

NASA Astrophysics Data System (ADS)

The isotope Technetium-99 (99Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO4]-, Tc represents long-term concern to the biosphere. Various options have been considered to manage 99Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric acid and extraction of U and Tc in organic media, previously developed methods can be used to separate Tc from U, convert the separate Tc stream to the metal and reuse the uranium component of the fuel. A variety of metallic waste forms, ranging from pure Tc metal to ternary Tc alloys combined with stainless steel (SS) and Zr are proposed. The goal of this work was to examine three major questions: What is the optimal method to separate Tc from U? After separation, what is the most efficient method to convert the Tc stream to Tc metal? Finally, what is the corrosion behavior of Tc metal, Tc-SS alloys and Tc-Zr-SS alloys in 0.01M NaCl? The goal is to predict the long term behavior of Tc metallic waste in a hypothetical storage environment. In this work, three methods have been used to separate Tc from U: anionic exchange resin, liquid-liquid extraction and precipitation. Of the three methods studied, anionic exchange resins is the most selective. After separation of Tc from U, three different methods were studied to convert the Tc stream to the metal: thermal treatment under hydrogen atmosphere, electrochemical and chemical reduction of pertechnetate in aqueous media. The thermal treatment of the Tc stream under hydrogen atmosphere is the preferred method to produce Tc metal. After Tc metal is isolated, it will be incorporated into a metal host phase. Three different waste forms were produced for corrosion studies in this work: Pure Tc metal, SS(Tc 2 wt%)Zr and SS(Tc 1.34 wt%) alloys. Corrosion rate measurements indicate that both SS(Tc 2 wt%)Zr and SS(Tc 1.34 wt%) alloys corrode more slowly than metallic Tc in the solutions tested.

Mausolf, Edward John

44

Tributyl phosphate impregnated sorbent for plutonium--uranium separation  

Microsoft Academic Search

Extraction, or reverse-phase partition chromatography, as used mostly for analytical separations, employs an organic solvent extractant as a stationary phase on an inert support material. This technique has the advantage of utilizing the versatility of solvent extraction systems with the less expensive operation of ion exchange equipment. Bayer AG Lewatit OC-1023, a tributyl phosphate impregnated sorbent developed for extraction chromatography,

C. E. Alford; J. D. Navratil

1978-01-01

45

Supercritical fluid extraction and separation of uranium from other actinides.  

PubMed

The feasibility of separating U from nitric acid solutions of mixed actinides using tri-n-butylphosphate (TBP)-modified supercritical fluid carbon dioxide (sc-CO2) was investigated. The actinides U, Np, Pu, and Am were extracted into sc-CO2 modified with TBP from a range of nitric acid concentrations, in the absence of, or in the presence of, a number of traditional reducing and/or complexing agents to demonstrate the separation of these metals from U under sc-CO2 conditions. The separation of U from Pu using sc-CO2 was successful at nitric acid concentrations of less than 3M in the presence of acetohydroxamic acid (AHA) or oxalic acid (OA) to mitigate Pu extraction, and the separation of U from Np was successful at nitric acid concentrations of less than 1M in the presence of AHA, OA, or sodium nitrite to mitigate Np extraction. Americium was not well extracted under any condition studied. PMID:24801893

Quach, Donna L; Mincher, Bruce J; Wai, Chien M

2014-06-15

46

Selective Recovery of Enriched Uranium from Inorganic Wastes  

SciTech Connect

Uranium as U(IV) and U(VI) can be selectively recovered from liquids and sludge containing metal precipitates, inorganic salts, sand and silt fines, debris, other contaminants, and slimes, which are very difficult to de-water. Chemical processes such as fuel manufacturing and uranium mining generate enriched and natural uranium-bearing wastes. This patented Framatome ANP (FANP) uranium recovery process reduces uranium losses, significantly offsets waste disposal costs, produces a solid waste that meets mixed-waste disposal requirements, and does not generate metal-contaminated liquids. At the head end of the process is a floating dredge that retrieves liquids, sludge, and slimes in the form of a slurry directly from the floor of a lined surface impoundment (lagoon). The slurry is transferred to and mixed in a feed tank with a turbine mixer and re-circulated to further break down the particles and enhance dissolution of uranium. This process uses direct steam injection and sodium hypochlorite addition to oxidize and dissolves any U(IV). Cellulose is added as a non-reactive filter aid to help filter slimes by giving body to the slurry. The slurry is pumped into a large recessed-chamber filter press then de-watered by a pressure cycle-controlled double-diaphragm pump. U(VI) captured in the filtrate from this process is then precipitated by conversion to U(IV) in another Framatome ANP-patented process which uses a strong reducing agent to crystallize and settle the U(IV) product. The product is then dewatered in a small filter press. To-date, over 3,000 Kgs of U at 3% U-235 enrichment were recovered from a 8100 m2 hypalon-lined surface impoundment which contained about 10,220 m3 of liquids and about 757 m3 of sludge. A total of 2,175 drums (0.208 m3 or 55 gallon each) of solid mixed-wastes have been packaged, shipped, and disposed. In addition, 9463 m3 of low-U liquids at <0.001 KgU/m3 were also further processed and disposed.

Kimura, R. T.

2003-02-26

47

Sample selection and testing of separation processes  

NASA Technical Reports Server (NTRS)

Phase partitioning, which has become an important tool for the separation and purification of biological materials, was studied. Instruments available for this technique were researched and a countercurrent distribution apparatus, the Biosheff MK2N, was purchased. Various proteins, polysaccharides and cells were studied as models to determine operating procedures and conditions for this piece of equipment. Results were compared with those obtained from other similar equipment, including a nonsynchronous coil planet centrifuge device. Additionally, work was done with affinity ligands attached to PEG, which can further enhance the separation capabilities of phase partitioning.

Karr, L. J.

1985-01-01

48

Quantum criticality in selected uranium intermetallic and organometallic compounds  

NASA Astrophysics Data System (ADS)

My thesis presents the studies of the bulk properties of materials that exhibit unusual low-temperature properties due to the proximity of a quantum-critical point (QCP), for which long-range magnetic order can be suppressed to 0 K as a consequence of quantum fluctuations. A material can be tuned to the QCP by variation of a non-thermal control parameter such as hydrostatic pressure, magnetic field and chemical pressure/doping. Most of my experimental studies were performed at extreme conditions, such as high magnetic fields, low temperatures and/or high pressures. Two classes of materials were studied, namely uranium intermetallics and organometallics. The investigations on uranium intermetallics were done on compounds close to the edge of magnetism, i.e. the UCu4+xAl 8-x, UCuxAl5-x and UFe1-xNixAl compounds. Several of those compounds exhibit deviations from traditional Fermi-liquid theory and show non-Fermi liquid (NFL) scaling at low temperatures. Field-induced magnetic transitions were studied for some selected uranium compounds (UNiAl, UNiGa, UNiGe and UIrGe) as well. Furthermore, a study of organometallic quantum magnet (DTN: NiCl2-4SC(NH 2)2), which exhibits field-induced quantum criticality, is presented. In DTN, the magnetic-field induced polarization shows magneto-electric couplings between the antiferromagnetic Ni spins and the soft organic lattice.

Nasreen, Farzana

49

Isotope Separation by Selective Photodissociation of Glyoxal.  

National Technical Information Service (NTIS)

Dissociation products, mainly formaldehyde and carbon monoxide, enriched in a desired isotope of carbon, oxygen, or hydrogen are obtained by the selective photodissociation of glyoxal wherein glyoxal is subjected to electromagnetic radiation in a predeter...

J. B. Marling

1976-01-01

50

Effects of selected physical and chemical parameters on uranium uptake by the bacterium Chryseomonas MGF-48  

Microsoft Academic Search

The effect of selected physical and chemical parameters, including media composition, uranium concentration, and metabolic inhibitors, on uranium uptake from aqueous solution by Chryseomonas sp. MGF-48, a bacterium isolated from electroplating effluent, was analysed. It was found that 198 mg\\/g (dry weight) of uranium was taken up from a 150 ppm (mg\\/l) solution of uranium when cells were maintained under

F. Malekzadeh; A. M. Latifi; M. Shahamat; M. Levin; R. R. Colwell

2002-01-01

51

Studies on separation and purification of fission (99)Mo from neutron activated uranium aluminum alloy.  

PubMed

A new method has been developed for separation and purification of fission (99)Mo from neutron activated uranium-aluminum alloy. Alkali dissolution of the irradiated target (100mg) results in aluminum along with (99)Mo and a few fission products passing into solution, while most of the fission products, activation products and uranium remain undissolved. Subsequent purification steps involve precipitation of aluminum as Al(OH)3, iodine as AgI/AgIO3 and molybdenum as Mo-?-benzoin oxime. Ruthenium is separated by volatilization as RuO4 and final purification of (99)Mo was carried out using anion exchange method. The radiochemical yield of fission (99)Mo was found to be >80% and the purity of the product was in conformity with the international pharmacopoeia standards. PMID:24657474

Rao, Ankita; Kumar Sharma, Abhishek; Kumar, Pradeep; Charyulu, M M; Tomar, B S; Ramakumar, K L

2014-07-01

52

Rubber separators for tomorrow: performance characteristics and selection guide  

NASA Astrophysics Data System (ADS)

A brief description is given of the basic differences in manufacturing processes and composition of the three types of rubber separator, namely: (i) sulfur-cured, hard rubber, ACE-SIL® separator; (ii) electron-beam crosslinked, FLEX-SIL® rubber separator; (iii) coated glass-mat MICROPOR-SIL® separator containing rubber. The physical, chemical, electrical and electrochemical properties of the three types of rubber separator are considered and the primary differences are explained. The beneficial performance characteristics found with rubber separators are presented, such as on-charge voltage characteristics, electrochemical compatibility for float-charging systems, retardation of antimony transfer, prevention of dendrite growth, and good wettability. Based on analysis of separator properties and battery requirements, a selection guide for rubber separators applicable to various types of lead/acid battery is compiled.

Paik, Syng L.; Terzaghi, Giovanni

53

Method for the Separation of Uranium from Plutonium Concentrates and Subsequent Colorimetric Measurements as the Bromo-PADAP Complex.  

National Technical Information Service (NTIS)

Uranium is separated from plutonium and other impurities by solvent-extraction using tributyl phosphate/odourless kerosene (TBP/OK). The uranium in solvent is measured colourimetrically using the sensitive chromogenic reagent bromo-PADAP (2-(5-bromo-2-pyr...

M. A. Mair, D. J. Savage

1986-01-01

54

??????????????????????????????????????????????????????????????????????? D2EHPA SEPARATION OF URANIUM FROM TRISODIUM PHOSPHATE SOLUTION BY D2EHPA IMPREGNATED RESINS ????????? ???????????1, ??????? ??????????1 ??? ????? ????????????1  

Microsoft Academic Search

In the monazite ore breakdown by alkali process to separate nuclear elements and rare earth elements composed in this phosphate ore, trisodium phosphate byproduct from the digestion process may contain uranium up to 300 ppm. Therefore, it is necessary to purify this trisodium phosphate. This study has used di(2-ethylhexyl) phosphoric acid (D2EHPA) impregnated resins to extract uranium from the trisodium

Uthaiwan Injarean; Pipat Pichestapong; Wannee Srinuttrakul

55

THE RECOVERY OF URANIUM FROM GAS MIXTURE  

Microsoft Academic Search

A method of separating uranium from a mixture of uranium hexafluoride ; and other gases is described that comprises bringing the mixture into contact ; with anhydrous calcium sulfate to preferentially absorb the uranium hexafluoride ; on the sulfate. The calcium sulfate is then leached with a selective solvent for ; the adsorbed uranium. (AEC)

Jury

1964-01-01

56

Separation of Selected Bile Acids by TLC. I  

Microsoft Academic Search

Seven of the selected bile acids were investigated: cholic acid (C), chenodeoxycholic acid (CDC), deoxycholic acid (DC), lithocholic acid (LC), glycocholic acid (GC), glycodeoxycholic acid (GDC), and glycolithocholic acid (GLC). The retardation factor (RF), ?RF values, the separation factors (?), resolution factors (RS), as well as the constants of the pair separation (RF ), indicate that the mobile phase n?heptane–ethyl

A. Pyka; M. Do?owy

2003-01-01

57

Validation of Electrochemically Modulated Separations Performed On-Line with MC-ICP-MS for Uranium and Plutonium Isotopic Analyses  

SciTech Connect

The most time consuming process in uranium or plutonium isotopic analyses is performing the requisite chromatographic separation of the actinides. Filament preparation for thermal ionization (TIMS) adds further delays, but is generally accepted due to the unmatched performance in trace isotopic analyses. Advances in Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) are beginning to rival the performance of TIMS. Methods, such as Electrochemically Modulated Separations (EMS) can efficiently pre-concentrate U or Pu quite selectively from small solution volumes in a matrix of 0.5 M nitric acid. When performed in-line with ICP-MS, the rapid analyte release from the electrode is fast, and large transient analyte signal enhancements of >100 fold can be achieved as compared to more conventional continuous nebulization of the original starting solution. This makes the approach ideal for very low level isotope ratio measurements. In this paper, some aspects of EMS performance are described. These include low level Pu isotope ratio behavior versus concentration by MC-ICP-MS and uranium rejection characteristics that are also important for reliable low level Pu isotope ratio determinations.

Liezers, Martin; Olsen, Khris B.; Mitroshkov, Alexandre V.; Duckworth, Douglas C.

2010-08-11

58

Separation and mass spectrometry of nanogram quantities of uranium and thorium from thorium-uranium dioxide fuels  

SciTech Connect

A microchemical procedure was developed for the separation and isotopic analysis of U and Th from irradiated (Th,U)O/sub 2/ fuel. The separation procedure consisted of two stages; in the first a tributyl phosphate impregnated resin bead was equilibrated with the dissolved fuel in 0.08 M HF/6 M HNO/sub 3/ solution. The bead sorbed approximately 1.7 ..mu..g of U and 4.8..mu..g of Th and provided good separation of these from the fission products. In the second stage, the U and Th were back-extracted into 0.025 M HF/8 M HNO/sub 3/ solution, which contained a small anion-exchange membrane disk. The disk adsorbed approximately 14 ng of U and 45 ng of Th, and subsequently was transferred to the ionizing filament of a thermal-ionization mass spectrometer and covered with a starch deposit. Sensitivities were sufficiently high for sequential analysis of these quantities of Th and U from a single disk. Isotopic data obtained for a combined U and Th standard showed excellent agreement with certified values: overall bias and precision were < 0.03% and 0.2% relative standard deviation, respectively, for both elements. The applicability of the procedure to uranium fuels was also demonstrated. 6 figures, 2 tables.

Green, L.W.; Elliot, N.L.; Longhurst, T.H.

1983-12-01

59

Development of non-denaturing off-gel isoelectric focusing for the separation of uranium-protein complexes in fish.  

PubMed

An off-gel non-denaturing isoelectric focusing (IEF) method was developed to separate uranium-biomolecule complexes from biological samples as a first step in a multidimensional metalloproteomic approach. Analysis of a synthetic uranium-bovine serum albumin complex demonstrated the focusing ability of the liquid-phase IEF method and the preservation of most of the uranium-protein interactions. The developed method was applied to gill cytosol prepared from zebrafish (Danio rerio) exposed to depleted uranium. The results were compared in terms of resolution, recovery, and protein identities with those obtained by in-gel IEF using an immobilized pH gradient gel strip. PMID:24691723

Bucher, Guillaume; Frelon, Sandrine; Simon, Olivier; Lobinski, Ryszard; Mounicou, Sandra

2014-05-01

60

Selective separation of ultra-fine particles by magnetophoresis  

Microsoft Academic Search

The selective and-specific extraction of species of interest fiom local environmental and other sample sources are importaut fbr scientific research, industrial processes, and environmental applications. A novel process for selective separation of ultrafine particles using 'magnetophoresis' is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field are determined by magnetic,

T. Ying; F. Coyne Prenger; R. M. Wingo; L. A. Worl

2002-01-01

61

TLC of Selected Bile Acids: Detection and Separation  

Microsoft Academic Search

The selected bile acids such as: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), lithocholic acid (LC) were separated by using thin layer chromatography on glass plates precoated with silica gel 60 with a concentrating zone. A robust and sensitive detection procedure for selected bile acids using the sulphuric acid

A. Pyka

2008-01-01

62

A Novel Magnetic Separation Technique: Selective Separation of Ultrafine Particles by Magnetophoresis  

Microsoft Academic Search

The selective and specific extraction of species of interest from local environmental and other sample sources are important for scientific research, industrial processes, and environmental applications. A novel process for selective separation of magnetic particles using magnetophoresis is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field gradient are determined

F. Coyne Prenger; Laura A. Worl; Michael D. Johnson; Joseph A. Waynert; Robert M. Wingo

2004-01-01

63

Environmental distribution of uranium and other trace elements at selected Kosovo sites  

Microsoft Academic Search

This paper reports the results of a study using lichens as biomonitors to investigate the environmental distribution of uranium and other trace elements at selected Kosovo sites. The results suggested that the use of depleted uranium (DU) ammunitions in Kosovo did not cause a diffuse environmental contamination in such a way to have caused a detectable U enrichment in lichens.

Luigi A Di Lella; Luisa Frati; Stefano Loppi; Giuseppe Protano; Francesco Riccobono

2004-01-01

64

Selective leaching of uranium from uranium-contaminated soils: Progress report 1  

Microsoft Academic Search

Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminated or remove uranium to acceptable regulatory levels. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. This facility is presently called the Femald Environmental

C. W. Francis; A. J. Mattus; L. L. Farr; M. P. Elless; S. Y. Lee

1993-01-01

65

Separation of Uranium from Nitric and Hydrochloric-Acid Solutions with Extractant-Coated Magnetic Microparticles  

Microsoft Academic Search

The magnetically assisted chemical separation (MACS) process utilizes selective magnetic microparticle composites to separate dissolved metals from solution. In this study, MACS particles were coated with neutral and acidic organophosphorus extractants,octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), and bis(2-ethyl-hexyl)phosphoric acid (D2EHPA or HDEHP) and were evaluated for the separation of uranyl ions from nitric- and hydrochloric-acid solutions.

M. D. KAMINSKI; L. NUÑEZ

2000-01-01

66

Incorporating Term Selection Into Separable Nonlinear Least Squares Identification Methods  

Microsoft Academic Search

In this paper, a method for the integration of the Least absolute shrinkage and selection operator (Lasso) into Separable Nonlinear Least Squares (SNLS) algorithms is presented. Lasso is reformulated as an equality constrained linear regression. The original SNLS problem is then solved subject to the resulting equality constraints. Simulations using the proposed algorithm to fit a Laguerre model to the

Mohammad Rasouli; David Westwick; William Rosehart

2007-01-01

67

Radium Removal from Canadian Uranium Mining Effluents by a Radium-Selective Ion Exchange Complexer.  

National Technical Information Service (NTIS)

A laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the applicability of a radium-selective ion exchange complexer for removing radium from Canadian urani...

1984-01-01

68

New chromatographic materials for the separation and concentration of uranium from environmental matrices  

SciTech Connect

Extraction chromatography, in which an inert support is impregnated with an extractant solution to form a chromatographic resin, combines the specificity of extraction with the ease of operation of an ion exchange column, thereby overcoming the principal drawbacks of the two methods when used alone. Previous work in this laboratory on the design of selective extractants for use in nuclear fuel reprocessing and in nuclear waste treatment has led to the development of several new phosphorus-based neutral organic extractants. In this report, we examine the use of two of these materials as stationary phases in extraction chromatography for the isolation of uranium from environmental samples. 2 refs., 2 figs., 1 tab.

Horwitz, E.P.; Dietz, M.L.; Chiarizia, R.; Diamond, H.

1991-01-01

69

Chromatographic selectivity study of 4-fluorophenylacetic acid positional isomers separation.  

PubMed

Unique properties of the fluorine atom stimulate widespread use and development of new organofluorine compounds in agrochemistry, biotechnology and pharmacology applications. However, relatively few synthetic methods exhibit a high degree of fluorination selectivity, which ultimately results in the presence of structurally related fluorinated isomers in the synthetic product. This outcome is undesirable from a pharmaceutical perspective as positional isomers possess different reactivity, biological activity and toxicity as compared to the desired product. It is advantageous to control positional isomers in the early stages of the synthetic process, as rejection and analysis of these isomers will likely become more difficult in later stages. The current work reports the development of a chromatographic analysis of 2- and 3-fluorophenylacetic acid positional isomer impurities in 4-fluorophenylacetic acid (4-FPAA), a building block in the synthesis of an active pharmaceutical ingredient. The method is employed as a part of a Quality by Design Approach to control purity of the starting material in order to eliminate the presence of undesirable positional isomers in the final drug substance. During method development, a wide range of chromatographic conditions and structurally related positional isomer probe molecules were exploited in an effort to gain insight into the specifics of the separation mechanism. For the systems studied it was shown that the choice of organic modifier played a key role in achieving acceptable separation. Further studies encompassed investigation of temperature influence on retention and selectivity of the FPAA isomers separation. Thermodynamic analysis of these data showed that the selectivity of the 2- and 4- fluorophenylacetic acids separation was dominated by an enthalpic process, while the selectivity of the 4- and 3-fluorophenylacetic acids separation was exclusively entropy driven (Delta(DeltaH degrees approximately 0). Studies of chromatographic behavior were complemented by solid state NMR experiments which provided valuable information regarding the relationship between stationary phase solvation and selectivity. PMID:17548091

Chasse, Tyson; Wenslow, Robert; Bereznitski, Yuri

2007-07-13

70

Development of a Selective Calixarene Sensor for Uranium.  

National Technical Information Service (NTIS)

Traditionally, measurements of uranium in wastewater have been obtained by laboratory based instrumentation, such as inductively coupled plasma spectroscopy, ion-chromatography and radiochemical methods. However, such methods and equipment, whilst offerin...

C. Evans-Thooompson S. E. Field A. H. Jones M. J. Kan

2002-01-01

71

Selective separation of ultra-fine particles by magnetophoresis  

SciTech Connect

The selective and-specific extraction of species of interest fiom local environmental and other sample sources are importaut fbr scientific research, industrial processes, and environmental applications. A novel process for selective separation of ultrafine particles using 'magnetophoresis' is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field are determined by magnetic, gravitational, and drag fbrces. By controlling these fbrces, one is able to control the migration rates of different species and then magnetically fiactionate mixtures of species into discrete groups. This study demonstrated for the fist time the selective separation of various species, such as iron (111) oxide, cupric (11) oxide, samarium (In) oxide, and cerium (III) oxide, by magnetophoresis. To better understand this phenomenon, a fbrce-balance model was developed that provides a good interpretation of the experimental results.

Ying, T. (Tung-yu); Prenger, F. Coyne; Wingo, R. M. (Robert M.); Worl, L. A. (Laura A.)

2002-01-01

72

Separation of Selected Bile Acids by TLC. III. Separation on Various Stationary Phases  

Microsoft Academic Search

The aim of our study was to determine the optimum conditions of the separation of selected bile acids, such as cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC) using thin?layer chromatography on aluminum plates which are precoated with silica gel 60 (E. Merck, #1.05553), silica gel

A. Pyka; M. Do?owy

2004-01-01

73

Contribution to ASTM C-26. 05 Task Group: determination of impurities in uranium by ICP-AES after separation with TBP  

Microsoft Academic Search

Uranium metal or uranium oxide is dissolved in nitric acid. Hydrofluoric acid is added to insure complete dissolution of HF, NB, SI, SN, TA, W, and ZR. The uranium is separated from the impurity elements using a tributyl phosphate and carbon tetrachloride solution. The aqueous phase containing the impurity elements is aspirated into the inductively coupled plasma. The concentrations of

G. F. Larson; R. E. Slagle

1983-01-01

74

Charge-separation in uranium diazomethane complexes leading to C-H activation and chemical transformation.  

PubMed

The reaction of diphenyldiazomethane with [((t-BuArO)3tacn)UIII] (1) results in an eta(2)-bound diphenyldiazomethane uranium complex. This complex exhibits unusual electronic properties as a charge-separated species with a radical anionic open-shell ligand, [((t-BuArO)3tacn)UIV(eta2-NNCPh2)] (2). Treating Ph2CN2 with a uranium complex that contains a sterically more demanding adamantane functionalized ligand, [((AdArO)3tacn)UIII] (3) results in an unprecedented C-H activation and nitrogen insertion to produce a five-membered heterocyclic indazole complex, [((AdArO)3tacn)UIV(eta(2)-3-phen(Ind))] (5). X-ray crystallography and spectroscopic characterization of these two compounds show that the [((t-BuArO)3tacn)UIV(eta(2)-NNCPh2)] compound is a U(IV) complex with a radical anionic ligand, whereas [((AdArO)3tacn)UIV(eta(2)-3-phen(Ind))] is a U(IV) f (2) species with a closed-shell ligand. PMID:18266361

Lam, Oanh P; Feng, Patrick L; Heinemann, Frank W; O'Connor, Joseph M; Meyer, Karsten

2008-03-01

75

Process for producing enriched uranium having a {sup 235}U content of at least 4 wt. % via combination of a gaseous diffusion process and an atomic vapor laser isotope separation process to eliminate uranium hexafluoride tails storage  

DOEpatents

An uranium enrichment process capable of producing an enriched uranium, having a {sup 235}U content greater than about 4 wt. %, is disclosed which will consume less energy and produce metallic uranium tails having a lower {sup 235}U content than the tails normally produced in a gaseous diffusion separation process and, therefore, eliminate UF{sub 6} tails storage and sharply reduce fluorine use. The uranium enrichment process comprises feeding metallic uranium into an atomic vapor laser isotope separation process to produce an enriched metallic uranium isotopic mixture having a {sup 235} U content of at least about 2 wt. % and a metallic uranium residue containing from about 0.1 wt. % to about 0.2 wt. % {sup 235} U; fluorinating this enriched metallic uranium isotopic mixture to form UF{sub 6}; processing the resultant isotopic mixture of UF{sub 6} in a gaseous diffusion process to produce a final enriched uranium product having a {sup 235}U content of at least 4 wt. %, and up to 93.5 wt. % or higher, of the total uranium content of the product, and a low {sup 235}U content UF{sub 6} having a {sup 235}U content of about 0.71 wt. % of the total uranium content of the low {sup 235}U content UF{sub 6}; and converting this low {sup 235}U content UF{sub 6} to metallic uranium for recycle to the atomic vapor laser isotope separation process. 4 figs.

Horton, J.A.; Hayden, H.W. Jr.

1995-05-30

76

Sequential separation of lanthanides, thorium and uranium using novel solid phase extraction method from high acidic nuclear wastes.  

PubMed

A novel grafted polymer for selective extraction and sequential separation of lanthanides, thorium and uranium from high acidic wastes has been developed by grafting Merrifield chloromethylated (MCM) resin with octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) (MCM-CMPO). The grafting process is well characterized using FT-IR spectroscopy, (31)P and (13)C CPMAS (cross-polarized magic angle spin) NMR spectroscopy and CHNPS elemental analysis. The influence of various physico-chemical parameters during metal ion extraction by the resin phase are studied and optimized by both static and dynamic methods. The resin shows very high sorption capacity values of 0.960mmolg(-1) for U(VI), 0.984mmolg(-1) for Th(IV), 0.488mmolg(-1) for La(III) and 0.502mmolg(-1) for Nd(III) under optimum HNO(3) medium, respectively. The grafted polymer shows faster rate exchange kinetics (<5min is sufficient for 50% extraction) and greater preconcentration ability, with reusability exceeding 20 cycles. During desorption process, sequential separation of the analytes is possible with varying eluting agents. The developed grafted resin has been successfully applied in extracting Th(IV) from high matrix monazite sand, U(VI) and Th(IV) from simulated nuclear spent fuel mixtures. All the analytical data is based on triplicate analysis and measurements are within 3.5% rsd reflecting the reproducibility and reliability of the developed method. PMID:17178189

Kesava Raju, Ch Siva; Subramanian, M S

2007-06-25

77

Preconcentration and selective metal ion separation using chelating micelles.  

PubMed

Chelating aggregates consisting of Triton X100 host micelles and hydrophobic derivatives of PAN have been examined as suitable candidates for preconcentration and selective separation of transition metal ions through micellar-enhanced ultrafiltration. The effective accumulation in the surfactant-rich retentate of nickel(II), copper(II), cobalt(II), manganese(II) and zinc(II), present at trace levels in aqueous samples, has been achieved by operating at pH ca. 6 with a ligand having a binding constant to the host micelles higher than 2000 l./mol. The efficient separation of micelle-bound metal chelates from unreactive ions has been assessed, together with the feasibility of selective enrichment and purification of the investigated metal ions present in mixtures through a multistage process. PMID:18966066

Pramauro, E; Prevot, A B; Zelano, V; Hinze, W L; Viscardi, G; Savarino, P

1994-08-01

78

Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices.  

PubMed

A technique for the isolation of thorium (Th), plutonium (Pu), americium (Am), uranium (U) and strontium (Sr) isotopes from various environmental matrices has been adapted from a previously published method specific to water samples (Maxwell, 2006). Separation and isolation of the various elemental fractions from a single sub-sample is possible, thereby eliminating the need for multiple analyses. The technique involves sample dissolution, concentration via calcium phosphate co-precipitation, rapid column extraction using TEVA™, TRU™ and Sr-Spec™ resin cartridges, alpha spectrometry for Th, Pu, U and Am and Cerenkov counting for Sr. Various standard reference materials were analysed and chemical yields are in the range of 70-80% for Th, Am, U and Sr and 50-60% for Pu. Sample sizes of up to 10 L for water, 5 g for dry soil and sediment and 10 g for dry vegetation and seaweed can be processed using this technique. PMID:20609501

Harrison, Jennifer J; Zawadzki, Atun; Chisari, Robert; Wong, Henri K Y

2011-10-01

79

Variable Selection for Clustering by Separability Based on Ridgelines  

Microsoft Academic Search

A new variable selection algorithm is developed for clustering based on mode association. In conventional mixture-model-based clustering, each mixture component is treated as one cluster and the separation between clusters is usually measured by the ratio of between- and within-component dispersion. In this paper, we allow one cluster to contain several components depending on whether they merge into one mode.

Hyangmin Lee; Jia Li

2012-01-01

80

Improved separate solution method for determination of low selectivity coefficients.  

PubMed

Simple, fast, and theoretically substantiated experimental method for determination of improved selectivity coefficients is proposed. The method is based on the well-known fact that low selectivity coefficients determined by the separate solution method (SSM) are time-dependent and, upon our finding, this dependence is a well-defined linear function of time raised to the certain negative power. In particular, the selectivity coefficients obtained for equally charged primary and foreign ions by SSM linearly depend on time to the minus one-fourth. It was found that extrapolation of experimental data using this function to the intersection with Y axes gives reliable values of rather low selectivity coefficients (down to n × 10(-7)), which strongly differ from those measured using SSM and correspond well with the values obtained using the modified separate solution method (MSSM) proposed by Bakker. At the same time, the new method is free of one very essential limitation inherent to MSSM, namely, it is applicable after the conditioning of electrodes in the primary ion solution and can be repeated many times. PMID:24625060

Egorov, Vladimir V; Zdrachek, Elena A; Nazarov, Valentine A

2014-04-15

81

SEPARATION OF CADMIUM FROM URANIUM, COBALT, NICKEL, MANGANESE, ZINC, COPPER, TITANIUM, AND OTHER ELEMENTS BY CATION EXCHANGE CHROMATOGRAPHY  

Microsoft Academic Search

A study of the distribution curves of cations with AG 5OW-X8 resin in ; hydrochloric acid showed that most cations are adsorbed strongly from 0.5 N ; hydrochloric acid, while cadmium is not. This fact was used to develop a cation ; exchange chromatographic procedure to separate cadmium from uranium, cobalt, ; nickel, manganese, zinc, copper, and titanium. Other cations

F. W. E. Strelow; F. W. E

1960-01-01

82

Anion Separation by Selective Crystallization of Metal-Organic-Frameworks  

SciTech Connect

A novel approach for the separation of anions from aqueous mixtures was demonstrated, which involves their selective crystallization with metal-organic frameworks (MOFs) containing urea functional groups. Self-assembly of Zn{sup 2+} with the N,N{prime}-bis(m-pyridyl)urea (BPU) linker results in the formation of one-dimensional MOFs including various anions for charge balance, which interact to different extents with the zinc nodes and the urea hydrogen-bonding groups, depending on their coordinating abilities. Thus, Cl{sup -}, Br{sup -}, I{sup -}, and SO{sub 4}{sup 2-}, in the presence of BPU and Zn{sup 2+}, form MOFs from water, in which the anions coordinate the zinc and are hydrogen-bonded to the urea groups, whereas NO{sub 3}{sup -} and ClO{sub 4}{sup -} anions either do not form MOFs or form water-soluble discrete coordination complexes under the same conditions. X-ray diffraction, FTIR, and elemental analysis of the coordination polymers precipitated from aqueous mixtures containing equivalent amounts of these anions indicated total exclusion of the oxoanions and selective crystallization of the halides in the form of solid solutions with the general composition ZnCl{sub x}Br{sub y}I{sub z} {center_dot} BPU (x + y + z = 2), with an anti-Hofmeister selectivity. The concomitant inclusion of the halides in the same structural frameworks facilitates the rationalization of the observed selectivity on the basis of the diminishing interactions with the zinc and urea acidic centers in the MOFs when going from Cl{sup -} to I{sup -}, which correlates with decreasing anionic charge density in the same order. The overall crystal packing efficiency of the coordination frameworks, which ultimately determines their solubility, also plays an important role in the anion crystallization selectivity under thermodynamic equilibration.

Custelcean, Radu [ORNL

2006-01-01

83

The synthesis, characterization and application of iron oxide nanocrystals in magnetic separations for arsenic and uranium removal  

NASA Astrophysics Data System (ADS)

Arsenic and uranium in the environment are hazardous to human health and require better methods for detection and remediation. Nanocrystalline iron oxides offer a number of advantages as sorbents for water purification and environmental remediation. First, highly uniform and crystalline iron oxide nanocrystals (nMAG) were prepared using thermal decomposition of iron salts in organic solutions; for the applications of interest in this thesis, a central challenge was the adaptation of these conventional synthetic methods to the needs of low infrastructure and economically disadvantaged settings. We show here that it is possible to form highly uniform and magnetically responsive nanomaterials using starting reagents and equipment that are readily available and economical. The products of this approach, termed the 'Kitchen Synthesis', are of comparable quality and effectiveness to laboratory materials. The narrow size distributions of the iron oxides produced in the laboratory synthesis made it possible to study the size-dependence of the magnetic separation efficiency of nanocrystals; generally as the diameter of particles increased they could be removed under lower applied magnetic fields. In this work we take advantage of this size-dependence to use magnetic separation as a tool to separate broadly distributed populations of magnetic materials. Such work makes it possible to use these materials in multiplexed separation and sensing schemes. With the synthesis and magnetic separation studies of these materials completed, it was possible to optimize their applications in water purification and environmental remediation. These materials removed both uranium and arsenic from contaminated samples, and had remarkably high sorption capacities --- up to 12 wt% for arsenic and 30 wt% for uranium. The contaminated nMAG is removed from the drinking water by either retention in a sand column, filter, or by magnetic separation. The uranium adsorption process was also utilized for the enhanced detection of uranium in environmental matrices. By relying on alpha-particle detection in well-formed and dense nMAG films, it was possible to improve soil detection of uranium by more than ten-thousand-fold. Central for this work was a detailed understanding of the chemistry at the iron oxide interface, and the role of the organic coatings in mediating the sorption process.

Mayo, John Thomas

84

Feature Subset Selection, Class Separability, and Genetic Algorithms  

SciTech Connect

The performance of classification algorithms in machine learning is affected by the features used to describe the labeled examples presented to the inducers. Therefore, the problem of feature subset selection has received considerable attention. Genetic approaches to this problem usually follow the wrapper approach: treat the inducer as a black box that is used to evaluate candidate feature subsets. The evaluations might take a considerable time and the traditional approach might be unpractical for large data sets. This paper describes a hybrid of a simple genetic algorithm and a method based on class separability applied to the selection of feature subsets for classification problems. The proposed hybrid was compared against each of its components and two other feature selection wrappers that are used widely. The objective of this paper is to determine if the proposed hybrid presents advantages over the other methods in terms of accuracy or speed in this problem. The experiments used a Naive Bayes classifier and public-domain and artificial data sets. The experiments suggest that the hybrid usually finds compact feature subsets that give the most accurate results, while beating the execution time of the other wrappers.

Cantu-Paz, E

2004-01-21

85

Uranium  

SciTech Connect

The two important oxidation states for uranium in natural environments are 4+ and 6+. Compounds containing quadrivalent uranium are insoluble in mildly acidic to alkaline conditions; whereas, those containing the linearly uranyl moiety (O=U=O)2+, are highly soluble and mobile. In solution, UO22+ forms soluble complexes with carbonate, oxalate, and hydroxide; UO22+ is also highly susceptible to adsorption either by organic matter, Fe oxyhydroxides, or precipitation with various anions, such as silicate, vanadate, arsenate, and phosphate. In ground water systems U(VI) is reduced to U(IV) if an effective reductant is present, such as H2S. Other reducing agents may be fossil plants, methane, and transported humic material. Uranium minerals display an extraordinary range structural and chemical variability, resulting from the different chemical conditions under which U minerals are formed.

Grenthe, Ingmar; Buck, Edgar C.; Drozdynski, J.; Fujino, T.; Albrecht-Schmitt, Thomas; Wolf, Steven F.

2006-07-31

86

Method for producing a selectively permeable separation module  

DOEpatents

A method and apparatus is provided for casting a polymeric membrane on the inside surface of porous tubes to provide a permeate filter system capable of withstanding hostile operating conditions and having excellent selectivity capabilities. Any polymer in solution, by either solvent means or melt processing means, is capable of being used in the present invention to form a thin polymer membrane having uniform thickness on the inside surface of a porous tube. Multiple tubes configured as a tubular module can also be coated with the polymer solution. By positioning the longitudinal axis of the tubes in a substantially horizontal position and rotating the tube about the longitudinal axis, the polymer solution coats the inside surface of the porous tubes without substantially infiltrating the pores of the porous tubes, thereby providing a permeate filter system having enhanced separation capabilities.

Stone, Mark L. (Idaho Falls, ID); Orme, Christopher J. (Shelley, ID); Peterson, Eric S. (Idaho Falls, ID)

2000-03-14

87

The selective leaching of uranium, vanadium and phosphorus from phosphate ore with hydrochloric acid  

NASA Astrophysics Data System (ADS)

The selective leaching of uranium, vanadium, and phosphorus from phosphate ore may be useful in by-product recovery. Experimental results have shown that it is possible to preferentially remove uranium from phosphate ore using dilute HCl (0.05 M). 93 pct of the uranium is leached within 90 min, leaving 94 pct of the phosphorus and 82 pct of the vanadium unattacked. Phosphorus may then be removed by increasing the pH. The apparent activation energies and orders for the leaching reactions were found. For uranium, the apparent order with respect to H+ is 1.05 and the apparent activation energy is 7750 J. The apparent order for the leaching of the vanadium minerals with respect to H+ is 1.93 and the apparent activation energy is 12800 J. The phosphorus reaction has an apparent order, with respect to H+, of 1.98 and an apparent activation energy of 10200 J. The uranium readsorbs at longer times. The readsorption reaction is a function of temperature, particle size, and H+ concentration. Two methods of selectivity analysis were used in the analysis of the data-end point analysis and initial rate analysis.

Clements, J. L.; Prisbrey, K. A.; Taylor, P. R.

1980-06-01

88

Selective separation of phosphate and fluoride from semiconductor wastewater.  

PubMed

Hydrofluoric acid (HF) and phosphoric acid (H(3)PO(4)) are widely used in semiconductor industry for etching and rinsing purposes. Consequently, significant amount of wastewater containing phosphate and fluoride is generated. Selective separation of phosphate and fluoride from the semiconductor wastewater, containing 936 mg/L of fluoride, 118 mg/L of phosphate, 640 mg/L of sulfate, and 26.7 mg/L of ammonia, was studied. Chemical precipitation and flotation reactions were utilized in the two-stage treatment processes. The first-stage reaction involved the addition of magnesium chloride (MgCl(2)) to induce selective precipitation of magnesium phosphate. The optimal condition was pH 10 and molar ratio, [Mg(2 + )]/[(PO(4) (3-))], of 3:1, and 66.2% of phosphate was removed and recovered as bobierrite (Mg(3)(PO(4))(2).8H(2)O). No reaction was found between MgCl(2) and fluoride. Calcium chloride (CaCl(2)) was used in the second-stage reaction to induce precipitation of calcium fluoride and calcium phosphate. The optimum molar ratio, [Ca(2 + )]/[F(-)], was 0.7 at pH 10, and residual fluoride concentration of 10.7 mg/L and phosphate concentration of lower than 0.5 mg/L was obtained. Thermodynamic equilibrium was modeled with PHREEQC and compared with experimental results. Sodium dodecylsulfate (SDS) was an effective collector for subsequent solid-liquid removal via dispersed air flotation (DiAF). The study demonstrated that phosphate can be selectively recovered from the wastewater. Potential benefits include recovery of phosphate for reuse, lower required dosage of calcium for fluoride removal, and less amount of CaF(2) sludge. PMID:19474500

Warmadewanthi, B; Liu, J C

2009-01-01

89

Separation of Uranium and Rare Earth Elements with High Purity from Low-Grade Gibbsite-Bearing Shale Ore by Different Chelating Resins  

Microsoft Academic Search

It is very difficult to recover uranium and rare earth elements (REEs) from low-grade ore especially gibbsite-bearing shale. The difficulty lies not only in the separation of uranium from REEs, but also the very low concentration of uranyl ions and REEs comparison with other metal ions in liquor. In this study, we perform the recovery in three steps. In the

Mohammed F. Hamza; Ibrahim E. El Aassy; Fadia Y. Ahmed; Adel A.-H. Abdel-Rahman; Ayman M. Atta

2012-01-01

90

Separation and mass spectrometry of nanogram quantities of uranium and thorium from thorium-uranium dioxide fuels  

Microsoft Academic Search

A microchemical procedure was developed for the separation and isotopic analysis of U and Th from irradiated (Th,U)Oâ fuel. The separation procedure consisted of two stages; in the first a tributyl phosphate impregnated resin bead was equilibrated with the dissolved fuel in 0.08 M HF\\/6 M HNOâ solution. The bead sorbed approximately 1.7 ..mu..g of U and 4.8..mu..g of Th

L. W. Green; N. L. Elliot; T. H. Longhurst

1983-01-01

91

Separation and Purification of Uranium by Ion Exchange on Stannic Phosphate.  

National Technical Information Service (NTIS)

Exchange of uranium, plutonium and some fission product elements was investigated on stannic phosphate (SnP) exchanger from nitric acid solutions. Batch equilibration studies exhibited stronger absorption of plutonium (IV) and some of the fission products...

P. C. Mayankutty M. N. Nadkarni K. S. Venkateswarlu

1977-01-01

92

Separacao de tracos de neptunio de solucoes de uranio por cromatografia de extracao. (Neptunium separation in trace levels from uranium solutions by extraction chromatography).  

National Technical Information Service (NTIS)

Neptunium and uranium behavior in extraction chromatography system, aiming the separation of microquantities of neptunium from uranyl nitrate solutions is described. Tri-n-octylamina (TOA), tri-n-butylphosphate (TBP), thenoyltrifluoroacetone (TTA) as stat...

M. E. B. Figols

1991-01-01

93

Removal of toxic substances by a selective membrane plasma separator.  

PubMed

We devised a method of plasma exchange with dialysis (PED), in which selective plasma exchange (sPE) is performed using a selective membrane plasma separator (EC-2A) with an albumin-sieving coefficient of 0.3 while the dialysate flows outside the hollow fibers, and reported the usefulness of the system for treating acute liver failure. Thereafter, EC-4A with an albumin-sieving coefficient of 0.6 was developed, which was expected to be even more effective for removing protein-bound substances. In order to examine whether or not EC-4A might be applicable to blood purification therapy against drug poisoning, we compared the efficacies of sPE, PED, and direct hemoperfusion (DHP) using an activated carbon column for the removal of phenobarbital and lithium. Subjects undergoing the extracorporeal circulation study were assigned to the sPE group, PED group, or DHP group, and the changes in the blood concentrations of phenobarbital and lithium were measured over 180?min. A significant decrease of the phenobarbital concentration over time was seen in the PED group, as compared to that in the sPE group (P?

Nakae, Hajime; Hattori, Tomoko; Igarashi, Toshiko; Okuyama, Manabu; Tajimi, Kimitaka

2014-06-01

94

Phosphonated cross-linked polyethylenimine for selective removal of uranium ions from aqueous solutions.  

PubMed

Among many remediation techniques for metal ion removal, polymeric adsorbents are efficient and widely applied. This has made them comparable with other remediation techniques in terms of technical and economic efficiency, feasibility as well as green technology. This study was dedicated to the development of an insoluble modified chelating polymer for use as an adsorbent for abstraction of uranium from wastewaters. Cross-linked polyethylenimine (CPEI) was phosphonated by phosphorous acid for selective removal of uranium ions. The binding affinity of the phosphonated cross-linked polyethylenimine (PCPEI) to uranium ions was assessed as well as its ability to be regenerated for reuse. It exhibited high removal percentage for uranium ions up to 99% with high selectivity even in the presence of competing ions (Mn, Ni, As). The Freundlich isotherm was found to be the best fit describing the adsorption process of uranyl ions onto the PCPEI. The pseudo-second-order equation was found to better explain the adsorption kinetics, implying chemisorption. The thermodynamic study of the adsorption revealed high activation energies which confirmed the chemisorption as the mechanism of adsorption. PMID:22678208

Saad, Dalia M G; Cukrowska, Ewa M; Tutu, Hlanganani

2012-01-01

95

Selective Separation of Coal Feedstocks for Conversion by Magnetic Separation Techniques.  

National Technical Information Service (NTIS)

The Open-Gradient Magnetic Separation (OGMS) technique can separate particles on the basis of small differences in magnetic susceptibility. The highly reactive coal macerals are diamagnetic while the minerals and less reactive macerals range from slightly...

E. C. Hise A. S. Holman

1981-01-01

96

Determination of hexavalent and tetravalent uranium in phosphate ores through hydrochloric acid selective leaching  

Microsoft Academic Search

The tetravalent and hexavalent uranium content of three Egyptian phosphate type ore samples namely; Sebayia, Abu Tartur and\\u000a Qatrani have been studied through selective leaching by hydrochloric acid at normal, oxidized and reduced conditions at an\\u000a amount of hydrochloric acid less than the stoichiometric value i.e. before phosphoric acid production. Oxidizing condition\\u000a is attained by incorporating 2% of manganese dioxide

Hisham K. Fouad

2010-01-01

97

Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results  

Microsoft Academic Search

An analytical procedure was established in order to obtain selective fractions containing radium isotopes (228Ra), thorium (232Th), and rare earths from RETOTER (REsíduo de TÓrio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium

Antonio Alves de Freitas; Adir Janete Godoy Dos Santos; Brigitte Roxana Soreanu Pecequilo

2008-01-01

98

Solvent Extraction Separation and Spectrographic Determination of Palladium, Rhodium and Ruthenium in Uranium.  

National Technical Information Service (NTIS)

The determination of Pd, Rh and Ru in uranium at low ppm level, using solvent extraction has been studied. BPHA, TNOA, TOPO and TBP have been tried as complexing agents; TBP in hexane and 5 M nitric acid medium provides a virtually quantitative extraction...

C. Capdevila, F. A. Alduan

1980-01-01

99

Separating the Minor Actinides Through Advances in Selective Coordination Chemistry  

SciTech Connect

This report describes work conducted at the Pacific Northwest National Laboratory (PNNL) in Fiscal Year (FY) 2012 under the auspices of the Sigma Team for Minor Actinide Separation, funded by the U.S. Department of Energy Office of Nuclear Energy. Researchers at PNNL and Argonne National Laboratory (ANL) are investigating a simplified solvent extraction system for providing a single-step process to separate the minor actinide elements from acidic high-level liquid waste (HLW), including separating the minor actinides from the lanthanide fission products.

Lumetta, Gregg J.; Braley, Jenifer C.; Sinkov, Sergey I.; Carter, Jennifer C.

2012-08-22

100

Selective separation of coal feedstocks for conversion by magnetic separation techniques  

Microsoft Academic Search

The Open-Gradient Magnetic Separation (OGMS) technique can separate particles on the basis of small differences in magnetic susceptibility. The highly reactive coal macerals are diamagnetic while the minerals and less reactive macerals range from slightly diamagnetic to paramagnetic with the pyritic minerals exhibiting the greatest positive magnetic susceptibility. OGMS can spread a falling stream of fine coal into a spectrum

E. C. Hise; A. S. Holman

1981-01-01

101

Enriched Uranium  

NSDL National Science Digital Library

This Wikipedia website provides information about the various concentrations of uranium used for different applications. Topics include a brief description of the grades of uranium and methods of isotope separation. There are also links to other aspects of uranium enrichment and related information. This information lays the foundation for informed discussion about the potential of nuclear energy and the risks of nuclear proliferation.

Wikipedia

102

Evaluation of selected neutralizing agents for the treatment of uranium tailings leachates. Laboratory progress report  

SciTech Connect

Laboratory experiments were conducted to evaluate the performance of selected neutralizing agents for the treatment of uranium tailings solutions. Highly acidic tailings solutions (pH<2) from the Lucky Mc Mill in Gas Hills, Wyoming and the Exxon Highlands Mill near Casper, Wyoming were neutralized to a pH of 7 or greater using seven neutralizing agents. Reagents used included: Fly Ash from Boardman Coal Plant, Boardman, Oregon; Fly Ash from Wyodak Coal Plant, Gillette, Wyoming; Calcium carbonate (CaCO/sub 3/) reagent grade; Calcium hydroxide (Ca(OH)/sub 2/) reagent grade; Magnesium oxide (MgO) reagent grade; Sodium carbonate (Na/sub 2/CO/sub 3/) reagent grade; and Sodium hydroxide (NaOH) reagent grade. Evaluation of the effectiveness for the treatment of uranium tailings solutions for the selected neutralizing agents under controlled laboratory conditions was based on three criteria. The criteria are: (1) treated effluent water quality, (2) neutralized sludge handling and hydraulic properties, and (3) reagent costs and acid neutralizing efficiency. On the basis of these limited laboratory results calcium hydroxide or its dehydrated form CaO (lime) appears to be the most effective option for treatment of uranium tailings solutions.

Sherwood, D.R.; Serne, R.J.

1983-02-01

103

Separation of Selected Bile Acids by TLC. VI. Separation on Cyano? and Diol?Modified Silica Layers  

Microsoft Academic Search

Seven selected bile acids: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC) were separated on silica gel modified by cyano and diol groups, with the use of a mobile phase: n?hexane–ethyl acetate–acetic acid in different volume compositions, at 18°C. The estimation of separation was carried out

A. Pyka; M. Do?owy

2005-01-01

104

Measurements of Position Angle and Separation of Selected Binary Stars  

NASA Astrophysics Data System (ADS)

We report on measurements of position angle and separation of physical binary systems. Many such systems, characterized as "neglected binaries" by the Washington Double Star Catalog of the USNO, are included in our sample lists, some ignored for more than 100 years. The data reported here was acquired at the 31 inch NURO telescope near Flagstaff, AZ. We have found that many stars listed as neglected seem to show no change in separation and position angle for many years, suggesting that they are not physical binaries. We thank the Puerto Rico Space Grant Consortium and the Humacao Campus MARC programs for their support of this project.

Muller, Rafael J.; Cersosimo, J. C.; Miranda, V. J.; Martinez, C.; Centeno, D.; Rivera, L.

2006-12-01

105

New selectivity in electrokinetic chromatography using a polymeric dye as novel separation carrier  

Microsoft Academic Search

A water-soluble polymeric dye was used as separation carrier in electrokinetic chromatography. For separations of aromatic analytes, alternative selectivities as compared to a sodium dodecyl sulfate system were obtained. Separation performance in such a system was further influenced and controlled by the application of a counter pressure from the cathodic side and by varying the modifier content over a wide

S Kolb; J. P Kutter; T Welsch

1997-01-01

106

Feature Subset Selection, Class Separability, and Genetic Algorithms  

Microsoft Academic Search

The performance of classiflcation algorithms in machine learn- ing is afiected by the features used to describe the labeled examples pre- sented to the inducers. Therefore, the problem of feature subset selection has received considerable attention. Genetic approaches to this problem usually follow the wrapper approach: treat the inducer as a black box that is used to evaluate candidate feature

Erick Cantú-paz

2004-01-01

107

Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results  

Microsoft Academic Search

An analytical procedure was established in order to obtain selective fractions containing radium isotopes (228Ra), thorium (232Th), and rare earths from RETOTER (REsi´duo de TO´rio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium

Antonio Alves de Freitas; Adir Janete Godoy dos Santos; Brigitte Roxana Soreanu Pecequilo; Alci´dio Abrão

2008-01-01

108

Combined procedure using radiochemical separation of plutonium, americium and uranium radionuclides for alpha-spectrometry  

Microsoft Academic Search

Radiochemical separation of Pu, Am and U was tested from synthetic solutions and evaporator concentrate samples from nuclear\\u000a power plants for isolation of each of them for alpha-spectrometry analysis. The separation was performed by anion-exchange\\u000a chromatography, extraction chromatography, using TRU resin, and precipitation techniques. The aim of the study was to develop\\u000a a sensitive analytical procedure for the sequential determination

Aluísio S. Reis; Eliane S. C. Temba; Geraldo F. Kastner; Roberto P. G. Monteiro

2011-01-01

109

Molecularly imprinted polymers for RGD selective recognition and separation.  

PubMed

Molecularly imprinted polymers that could recognize the tripeptide Arg-Gly-Asp have been produced with the use of two functional monomers and three different cross-linkers, respectively. Methacrylic acid and acrylamide were used as functional monomers and the role of the ethylene glycol dimethacrylate, trimethylpropane trimethacrylate and N,N'-methylene-bisacrylamide as crosslinking monomers, was investigated on their recognition capability. The % net rebinding and the imprinting factor values were obtained, giving for the methacrylic acid-trimethylpropane trimethacrylate polymer the highest values 12.3% and 2.44, respectively. In addition, this polymer presented lower dissociation constant (K(D)) value and the higher B (max)% of theoretical total binding sites than all the other polymers. Rebinding experiments with Lys-Gly-Asp, an analogue of Arg-Gly-Asp, and other different peptides, such as cholecystokinin C-terminal tri- and pentapeptide and gramicidin, further indicated the selectivity of methacrylic acid-trimethylpropane trimethacrylate copolymer for Arg-Gly-Asp giving specific selectivity factor values 1.27, 1.98, 1.31 and 1.67, respectively. PMID:18592344

Papaioannou, Emmanuel; Koutsas, Christos; Liakopoulou-Kyriakides, Maria

2009-03-01

110

Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results  

SciTech Connect

An analytical procedure was established in order to obtain selective fractions containing radium isotopes ({sup 228}Ra), thorium ({sup 232}Th), and rare earths from RETOTER (REsiduo de TOrio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium nitrate at IPEN -CNEN/SP. The paper presents preliminary results of {sup 228}Ra, {sup 226}Ra, {sup 238}U, {sup 210}Pb, and {sup 40}K concentrations in the selective fractions and total residue determined by high-resolution gamma spectroscopy, considering radioactive equilibrium of the samples.

Alves de Freitas, Antonio; Abrao, Alcidio [Centro de Quimica e do Meio Ambiente (Brazil); Godoy dos Santos, Adir Janete; Pecequilo, Brigitte Roxana Soreanu [Centro de Metrologia das Radiacoes Instituto de Pesquisas Energeticas e Nucleares Av. Prof. Lineu Prestes, 2242-Cidade Universitaria-Zip Code 05508-000 Sao Paulo-SP (Brazil)

2008-08-07

111

Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results  

NASA Astrophysics Data System (ADS)

An analytical procedure was established in order to obtain selective fractions containing radium isotopes (228Ra), thorium (232Th), and rare earths from RETOTER (REsíduo de TÓrio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium nitrate at IPEN -CNEN/SP. The paper presents preliminary results of 228Ra, 226Ra, 238U, 210Pb, and 40K concentrations in the selective fractions and total residue determined by high-resolution gamma spectroscopy, considering radioactive equilibrium of the samples.

de Freitas, Antonio Alves; Dos Santos, Adir Janete Godoy; Pecequilo, Brigitte Roxana Soreanu; Abra~O, Alcídio

2008-08-01

112

Selected annotated bibliography of the geology and occurrence of uranium-bearing marine black shales in the United States  

USGS Publications Warehouse

The bibliography consists of annotations or abstracts of selected reports that pertain to the geology and occurrence of uranium in marine black shales and their metamorphic equivalents in the United States. Only those reports that were available to the public prior to June 30, 1956, are included. Most of the reports may be consulted in the larger public, university, or scientific libraries. A few reports that have been released to the public in open file may be consulted at designated offices of the Geological Survey. An effort has been made to include only those references to shales whose uranium is believed to be of syngenetic origin and whose major source of radioactivity is uranium. Many general papers on the geology of uranium deposits refer to marine black shales, and some of these general papers have been included.

Fix, Carolyn E.

1956-01-01

113

Study on the use of macroporous cation exchange resins for the separation and purification of uranium from thorium.  

National Technical Information Service (NTIS)

The possibility of using macroporous cation exchange resins for the purification of uranium from thorium relevant to the final purification of uranium after reprocessing thorium breeder fuel was explored. Two macroporous cation exchange resins were studie...

R. K. Rastogi M. A. Mahajan N. K. Chaudhuri

1992-01-01

114

Geological and geochemical aspects of uranium deposits. A selected, annotated bibliography  

SciTech Connect

A bibliography of 479 references encompassing the fields of uranium and thorium geochemistry and mineralogy, geology of uranium deposits, uranium mining, and uranium exploration techniques has been compiled by the Ecological Sciences Information Center of Oak Ridge National Laboratory. The bibliography was produced for the National Uranium Resource Evaluation Program, which is funded by the Grand Junction Office of the Department of Energy. The references contained in the bibliography have been divided into the following eight subject categories: (1) geology of deposits, (2) geochemistry, (3) genesis O deposits, (4) exploration, (5) mineralogy, (6) uranium industry, (7) reserves and resources, and (8) geology of potential uranium-bearing areas. All categories specifically refer to uranium and thorium; the last category contains basic geologic information concerning areas which the Grand Junction Office feels are particularly favorable for uranium deposition. The references are indexed by author, geographic location, quadrangle name, geoformational feature, taxonomic name, and keyword.

Garland, P.A.; Thomas, J.M.; Brock, M.L.; Daniel, E.W. (comps.)

1980-06-01

115

Fast-steering mirror systems for the Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) program at Lawrence Livermore National Laboratory (LLNL)  

Microsoft Academic Search

We have successfully deployed several fast steering mirror systems in the Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) facility at Lawrence Livermore National Laboratory. These systems employ 25 mm to 150 mm optics and piezoelectric actuators to achieve microradian pointing accuracy with disturbance rejection bandwidths to a few hundred hertz.

James A. Watson; Kenneth Avicola; Anthony Page; Roger L. Peterson; Richard L. Ward

1995-01-01

116

Sulfate Separation by Selective Crystallization of a Urea-Functionalized Metal-Organic Framework  

SciTech Connect

Encapsulation of SO{sub 4}{sup 2-} into a Ni coordination framework functionalized with urea anion-binding groups allows selective separation of this strongly hydrophilic anion from a highly competitive aqueous environment.

Custelcean, Radu [ORNL; Sellin, Vincent [ORNL; Moyer, Bruce A [ORNL

2007-01-01

117

Selective aqueous extraction of organics coupled with trapping by membrane separation  

DOEpatents

An improvement to processes for the selective extractation of organic solutes from organic solvents by water-based extractants is disclosed, the improvement comprising coupling various membrane separation processes with the organic extraction process, the membrane separation process being utilized to continuously recycle the water-based extractant and at the same time selectively remove or concentrate organic solute from the water-based extractant.

van Eikeren, Paul (Bend, OR); Brose, Daniel J. (Bend, OR); Ray, Roderick J. (Bend, OR)

1991-01-01

118

Separation of uranium-233 by double decomposition of ThO$sub 2$ with sulfuric acid  

SciTech Connect

A method for separating /sup 233/U from irradiated thorium dioxide is presented in which the thorium dioxide changes to thorium sulfate when heated in H/sub 2/S0/sub 4/ (H/sub 2/0/sub 2/) solution. The thorium sulfat e is practically insoluble in this solution, while the /sup 233/U leaches out into the solution as U(VI). (DHM)

Akatsu, J.

1973-07-01

119

Optimal Band Selection for Hyperspectral Image Classification Based on InterClass Separability  

Microsoft Academic Search

Hyperspectral image's vast data volume brings about many problems in data processing. It also comes at a price that such wealthy spectral information is highly correlated. Selection of optimal bands is an effective means to mitigate the curse of dimensionality for remote sensing data. In this paper, we propose a new inter-class separability criterion, that is Spectral Separability Index, and

Jihao Yin; Yisong Wang; Zhanjie Zhao

2010-01-01

120

Flotation of molybdate oxyanions from dilute solutions Part II. Selective separation from phosphates, arsenates and silicates  

Microsoft Academic Search

Adsorbing colloid flotation was found to be an efficient method for selective separation of phosphates or silicates from aqueous solutions of molybdate oxyanions (binary mixtures); tertiary and quaternary mixtures of molybdates and arsenate, phosphate and silicate anions have been also separated effectively. The main parameters affecting this process, namely the concentrations of Fe(III) (used as co-precipitant), dodecylamine (used as surfactant

Y.-C. Zhao; A. I. Zouboulis; K. A. Matis

1996-01-01

121

Development of a composite palladium membrane for selective hydrogen separation at high temperature  

Microsoft Academic Search

In this paper a method is described for development of a composite palladium membrane for selective hydrogen separation at high temperature. Electroless plating is used to form a thin palladium film on a silver porous substrate. The composite formed showed excellent mechanical strength and very large selectivity for hydrogen. The studies performed so far suggest that electroless plating can be

Rakesh Govind; Devendra Atnoor

1991-01-01

122

Improvement of multi jet low pressure impactor for high collection efficiency of UF5 in the molecular laser isotope separation of uranium  

NASA Astrophysics Data System (ADS)

A numerical and experimental study for the collection of photo-produced UF 5 particles was performed for the low pressure impactors which have different design factors at typical flow conditions (upstream pressure of the impactor = 10-15 Torr, pressure ratio of downstream to upstream of the impactor, {P down}/{P up} = 0.2-0.5 ) in the molecular laser isotope separation of uranium at RIKEN (RIMLIS). Smaller {H}/{W} ratios (the distance between the impactor orifice exit and the impaction plate, H, divided by the orifice diameter of the impactor, W) and the smaller {P down}/{P up} were found to be preferable to obtain a higher collection efficiency from both numerical and experimental investigations. In addition it was experimentally demonstrated that the use of a 16 ?m laser system for the selective reaction of 235UF 6 to form 235UF 5 was not relevant for the study of the collection of UF 5 particles. So, we used an ultraviolet laser system (fourth harmonic YAG laser (266 nm) and an excimer laser (KrF, 248 nm)) which was more convenient to cope with various operating conditions. The collection efficiency was found to increase with the initial concentration of UF 5 molecules produced. Applying the improved impactor stage, we obtained a collection efficiency which was approximately 10 times higher than that of our previous work. Higher collection efficiencies of photo-produced UF 5 particles enriched in 235U reduce the enrichment cost.

Kuga, Yoshikazu; Jurcik, Benjamin; Satooka, Sakae; Takeuchi, Kazuo

1995-07-01

123

Ultrathin, molecular-sieving graphene oxide membranes for selective hydrogen separation.  

PubMed

Ultrathin, molecular-sieving membranes have great potential to realize high-flux, high-selectivity mixture separation at low energy cost. Current microporous membranes [pore size < 1 nanometer (nm)], however, are usually relatively thick. With the use of current membrane materials and techniques, it is difficult to prepare microporous membranes thinner than 20 nm without introducing extra defects. Here, we report ultrathin graphene oxide (GO) membranes, with thickness approaching 1.8 nm, prepared by a facile filtration process. These membranes showed mixture separation selectivities as high as 3400 and 900 for H2/CO2 and H2/N2 mixtures, respectively, through selective structural defects on GO. PMID:24092739

Li, Hang; Song, Zhuonan; Zhang, Xiaojie; Huang, Yi; Li, Shiguang; Mao, Yating; Ploehn, Harry J; Bao, Yu; Yu, Miao

2013-10-01

124

Isotope Separation.  

National Technical Information Service (NTIS)

Separation of isotopes is treated in a general way, with special reference to the production of enriched uranium. Uses of separated isotopes are presented quickly. Then basic definitions and theoretical concepts are explained: isotopic effects, non statis...

J. Ravoire

1978-01-01

125

A simple-rapid method to separate uranium, thorium, and protactinium for U-series age-dating of materials.  

PubMed

Uranium-series dating techniques require the isolation of radionuclides in high yields and in fractions free of impurities. Within this context, we describe a novel-rapid method for the separation and purification of U, Th, and Pa. The method takes advantage of differences in the chemistry of U, Th, and Pa, utilizing a commercially-available extraction chromatographic resin (TEVA) and standard reagents. The elution behavior of U, Th, and Pa were optimized using liquid scintillation counting techniques and fractional purity was evaluated by alpha-spectrometry. The overall method was further assessed by isotope dilution alpha-spectrometry for the preliminary age determination of an ancient carbonate sample obtained from the Lake Bonneville site in western Utah (United States). Preliminary evaluations of the method produced elemental purity of greater than 99.99% and radiochemical recoveries exceeding 90% for U and Th and 85% for Pa. Excellent purity and yields (76% for U, 96% for Th and 55% for Pa) were also obtained for the analysis of the carbonate samples and the preliminary Pa and Th ages of about 39,000 years before present are consistent with (14)C-derived age of the material. PMID:24681438

Knight, Andrew W; Eitrheim, Eric S; Nelson, Andrew W; Nelson, Steven; Schultz, Michael K

2014-08-01

126

Synthesis and characterization of new biopolymeric microcapsules containing DEHPA-TOPO extractants for separation of uranium from phosphoric acid solutions.  

PubMed

A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of [Formula: see text] ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of [Formula: see text] ions with the microdroplets of extractant, whereas it changed to intraparticle diffusion at higher acid concentration. The study also attempted identification of the diffusion paths of the ions within the microcapsules, and the mechanism of change of mass transfer rate during the uptake process. The prepared microcapsules preserved their entire capacity after three cycles of adsorption, and their breakthrough behaviour was well fitted by a new formula derived from shrinking core model. PMID:21545316

Outokesh, Mohammad; Tayyebi, Ahmad; Khanchi, Alireza; Grayeli, Fatemeh; Bagheri, Ghodrat

2011-01-01

127

A review of selected aspects of the effect of water vapor on fission gas release from uranium oxycarbide  

SciTech Connect

A selective review is presented of previous measurements and the analysis of experiments on the effect of water vapor on fission gas release from uranium oxycarbide. Evidence for the time-dependent composition of the uranium oxycarbide fuel; the diffusional release of fission gas; and the initial, rapid and limited release of stored fission gas is discussed. In regard to the initial, rapid release of fission gas, clear restrictions on mechanistic hypotheses can be deduced from the experimental data. However, more fundamental experiments may be required to establish the mechanism of the rapid release.

Myers, B.F.

1994-04-01

128

Introduction of structural affinity handles as a tool in selective nucleic acid separations  

NASA Technical Reports Server (NTRS)

The method is used for separating nucleic acids and other similar constructs. It involves selective introduction, enhancement, or stabilization of affinity handles such as single-strandedness in the undesired (or desired) nucleic acids as compared to the usual structure (e.g., double-strandedness) of the desired (or undesired) nucleic acids. The undesired (or desired) nucleic acids are separated from the desired (or undesired) nucleic acids due to capture by methods including but not limited to immobilized metal affinity chromatography, immobilized single-stranded DNA binding (SSB) protein, and immobilized oligonucleotides. The invention is useful to: remove contaminating genomic DNA from plasmid DNA; remove genomic DNA from plasmids, BACs, and similar constructs; selectively separate oligonucleotides and similar DNA fragments from their partner strands; purification of aptamers, (deoxy)-ribozymes and other highly structured nucleic acids; Separation of restriction fragments without using agarose gels; manufacture recombinant Taq polymerase or similar products that are sensitive to host genomic DNA contamination; and other applications.

Willson, III, Richard Coale (Inventor); Cano, Luis Antonio (Inventor)

2011-01-01

129

Microphase separated structures of block copolymer thin film with non-volatile selective solvent  

NASA Astrophysics Data System (ADS)

Microphase separated structures of block copolymer, polystyrene-b-polyisoprene (PS-b-PI, phiPS = 14%) including non-volatile selective solvent thin films were investigated using grazing incidence small angle X-ray scattering technique. The diethyl phthalate (DEP) was used as a non-volatile selective solvent which solves PS only. The DEP swelled PS phase selectively and the microphase separated structure transited from the PS spherical domain to the lamellar domain with an increase in DEP content in the bulk state. Similarly, the phase separated structure in the thin film prepared by spin cast on a silicon wafer from the mixture of toluene/DEP and block copolymer changed according to the initial DPE concentration. However, the morphologies developed in the thin film were shifted to the structures at lower DEP concentration than that expected from the initial concentration. Moreover, the cylindrical and lamellar domains were aligned parallel and perpendicularly to the substrate, respectively.

Yamamoto, Katsuhiro; Umegaki, Naoya; Matsutani, Taito; Takagi, Hideaki; Ito, Eri; Sakurai, Shinichi

2010-11-01

130

Insulator-based dielectrophoresis for the selective concentration and separation of live bacteria in water  

Microsoft Academic Search

Insulator-based dielectrophoresis (iDEP) was utilized to separate and concentrate selectively mixtures of two species of live bacteria simultaneously. Four species of bacteria were studied: the Gram-negative Escherichia coli and the Gram-positive Bacillus subtilis, B. cereus, and B. megaterium. Under an applied direct current (DC) electric field all the bacterial species exhibited negative dielectrophoretic behavior. The dielectrophoretic separations were carried out

Blanca H. Lapizco-Encinas; Blake A. Simmons; Eric B. Cummings; Yolanda Fintschenko

2004-01-01

131

[Selective separation of cinnamic and p-methoxycinnamic acids. The study on reactive extraction from mixture].  

PubMed

Cinnamic and p-methoxycinnamic acids have been separated from their mixture by reactive extraction with Amberlite LA-2 dissolved in n-heptane. The efficiency and the selectivity of their separation is controlled by the pH-value and extractant concentration, the optimum conditions being the pH-value of aqueous phase of 2 and the extractant concentration into the organic phase of 10 g/l. PMID:18389811

C?m?ru?, Maria; Galaction, Anca-Irina; Ca?caval, D

2007-01-01

132

Selective separation of Eu{sup 3+} using polymer-enhanced ultrafiltration  

SciTech Connect

A process to selectively remove {sup 241}Am from liquid radioactive waste was investigated as an actinide separation method applicable to Hanford and other waste sites. The experimental procedures involved removal of Eu, a nonradioactive surrogate for Am, from aqueous solutions at pH 5 using organic polymers in conjunction with ultrafiltration. Commercially available polyacrylic acid (60,000 MW) and Pacific Northwest Laboratory`s (PNL) synthesized E3 copolymer ({approximately}10,000 MW) were tested. Test solutions containing 10 {mu}g/mL of Eu were dosed vath each polymer at various concentrations in order to bind Eu (i.e., by complexation and/or cation exchange) for subsequent rejection by an ultrafiltration coupon. Test solutions were filtered with and without polymer to determine if enhanced Eu separation could be achieved from polymer treatment. Both polymers significantly increased Eu removal. Optimum concentrations were 20 {mu}g/mL of polyacrylic acid and 100 {mu}g/mL of E3 for 100% Eu rejection by the Amicon PM10 membrane at 55 psi. In addition to enhancement of removal, the polymers selectively bound Eu over Na, suggesting that selective separation of Eu was possible. This suggests that polymer-enhanced ultrafiltration is a potential process for separation of {sup 241}Am from Hanford tank waste, further investigation of binding agents and membranes effective under very alkaline and high ionic strength is warranted. This process also has potential applications for selective separation of toxic metals from industrial process streams.

Norton, M.V.

1994-03-01

133

Separation of positional isomers by the use of coupled shape-selective stationary phase columns.  

PubMed

The successful separation of 2- and 3-methyl-substituted positional isomers of butanol, butyl acetate, and butanoic acid and its ethyl ester, is reported. These compounds are of interest in the study of wine flavour, however the separation of the 2- and 3-methyl isomers may present problems, and more so in the presence of the wine matrix components, when single capillary column gas chromatography (GC) is used. The strategy to achieve separation was based on the use of shape-selective cyclodextrin derivative (CDD) capillary columns (commonly referred to as chiral columns). These columns provide simultaneous resolution of the enantiomeric pairs of the 2-methyl isomers, and at the same time the ability to separate the 3-methyl isomer from the 2-methyl is achieved in all but the case of the ( S)-2- and 3-methylbutanol. The advantages of using shape-selective columns to perform this study is demonstrated, with coupling of two CDD columns giving improved separations of these compounds. Although these compounds are relatively volatile, cryogenic modulated comprehensive two-dimensional GC was shown to provide good pulsed peak profiles with chiral separation in the first dimension when a thicker film trapping column segment was employed. The components of interest were well separated from other wine matrix components. PMID:12638047

Shao, Yajing; Marriott, Philip

2003-03-01

134

Dissolution of Uranium-Molybdenum ReACTOR Fuel Elements.  

National Technical Information Service (NTIS)

Uranium is separated from a uranium-molybdenum composition by contacting the composition with a gaseous mixture of hydrogen chloride and air at from 400 to 600 degrees C. to selectively volatilize a portion of the molybdenum as molybdenum oxychloride. The...

T. A. Gens

1964-01-01

135

Sequential separation of light rare-earth elements, thorium and uranium by miniaturized extraction chromatography: Application to isotopic analyses of silicate rocks  

Microsoft Academic Search

A new method for the concomitant separation of the light rare-earth elements (LREEs), thorium and uranium is described, and applied to the determination of 143Nd144Nd ratios, and concentrations of Sm, Nd, Th and U in silicate rocks, using isotope dilution and thermal ionization mass spectrometry. The proposed scheme is based on two recently introduced extraction chromatographic materials, referred to as

Christian Pin; JoséFrancisco Santos Zalduegui

1997-01-01

136

Super selective membranes in gas–liquid membrane contactors for olefin\\/paraffin separation  

Microsoft Academic Search

In the present paper, selective composite membranes containing sulfonated poly(ether ether ketone) (SPEEK) layers on top of a hydrophobic, polypropylene support are applied as absorber and desorber in a gas–liquid membrane contactor system for the separation of paraffins and olefins. The water present in the absorption liquid swells the hydrophilic polymer sufficiently, making the membranes olefin-selective. As a result, even

Kitty Nymeijer; Tymen Visser; Rijanne Assen; Matthias Wessling

2004-01-01

137

Simulation of nuclear-fuel solvent-extraction reprocessing 7. Separation of macroscopic amounts of plutonium and uranium by displacement reextraction of plutonium in reprocessing fast-reactor fuel (section 1)  

Microsoft Academic Search

These data have been obtained from simulating displacement reextraction in a system with two inputs (system for reprocessing a fast-reactor fuel), and they show that it is possible to obtain a uranium extract with not more than 100 ?g Pu\\/kg U in a counter current system with 18 stages to provide partial separation of the uranium and plutonium by reprocessing

É. V. Renard; M. Ya. Zel'venskii

1979-01-01

138

Selected bibliography pertaining to uranium occurrence in eastern New Mexico and west Texas and nearby parts of Colorado, Oklahoma, and Kansas. Interim report  

Microsoft Academic Search

Nearly 500 selected references to uranium and to stratigraphy, ; structure, and groundwater geology related to uranium-bearing formations in ; eastern New Mexico and West Texas and nearby parts of Colorado, Kansas, and ; Oklahoma are indexed topically and geographically. The list is nearly complete ; through 1972 and contains some references with later dates. (GRA)

W. I. Finch; J. C. Wright; M. W. Sullivan

1975-01-01

139

Selection of water-dispersible carbon black for fabrication of uranium oxicarbide microspheres  

Microsoft Academic Search

Fabrication of uranium oxicarbide microspheres, a component of TRISO fuel particles for high temperature nuclear power systems, is based on the internal gelation of uranium salts in the presence of carbon black. In order to obtain a high quality product, carbon black should remain dispersed during all phases of the gelation process. In this study, the surface and structural properties

Cristian I. Contescu; Frederick S. Baker; Rodney Dale Hunt; Jack Lee Collins; Timothy D. Burchell

2008-01-01

140

New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations  

SciTech Connect

The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be performed. A unifying feature of the ligand structures is the presence of one (or more) side arm with a pendent acidic function. When a metal ion is complexed within the central cavity of the ligand, ionization of the side arm(s) produces the requisite anion(s) for formation of an overall electroneutral complex. This markedly enhances extraction/transport efficiency for separations in which movement of aqueous phase anions of chloride, nitrate, or sulfate into an organic medium would be required. Through systematic structural variations, new ligands have been developed for efficient and selective separations of monovalent metal ions (e.g., alkali metal, silver, and thallium cations) and of divalent metal ion species (e.g., alkaline earth metal, lead, and mercury cations). Research results obtained in these fundamental investigations provide important insight for the design and development of ligands suitable for practical metal ion separation applications.

Bartsch, Richard A.

2012-06-04

141

SELECTIVE SEPARATION OF LEAD FROM ALKALINE ZINC SOLUTION BY SULFIDE PRECIPITATION  

Microsoft Academic Search

Zinc and lead are usually concomitantly present in Zn-Pb ores and solid wastes, such as electric arc furnace (EAF) dusts. One of the treatment methods is to extract zinc and lead from the ores and wastes by an alkaline leaching process if applicable. The selective and quantitative separation of lead from zinc is an important step in these processes. In

Zhao Youcai; Robert Stanforth

2001-01-01

142

Precursor Selection and Process Conditions in the Preparation of Carbon Membrane for Gas Separation: A Review  

Microsoft Academic Search

Carbon membranes prepared by pyrolysis\\/carbonization of polymeric precursors have been studied in the last few years as a promising candidate for gas separation process. As the aim of this paper, a review on polymer precursor selection and effect of pyrolysis conditions on carbon membrane characteristics and performances were discussed in detail. A number of different polymer precursors have been surveyed

W. N. W. Salleh; A. F. Ismail; T. Matsuura; M. S. Abdullah

2011-01-01

143

Thermodynamic principles of selectivity of organic solvents in separation of organosulfur compounds and hydrocarbons  

SciTech Connect

The efficiency of extractive separation depends on the ratio of the intermolecular forces prevailing in the extracting medium. The total energy of the intermolecular interaction of the extractant with the components to be separated can be characterized by the change in the molar free energy of their mutual solvation. The higher the proportion of the energy of the specific interaction in the overall balance of the intermolecular forces, the higher the efficiency of the extraction process. In an attempt to prove this premise the authors of this paper seek to evaluate the selectivity of a range of organic solvents in the separation of organosulfur compounds and hydrocarbons and to determine the dependence of extraction efficiency on the properties mentioned. Their test case involves the separation of petroleum sulfoxides and petroleum sulfones with some alcohols, esters, ketones, and amides.

Kozin, V.G.; Diyarov, I.N.; Okruzhnov, M.A.; Komleva, L.E.

1987-08-20

144

Functional Sorbents for Selective Capture of Plutonium, Americium, Uranium, and Thorium in Blood  

PubMed Central

Self-assembled monolayer on mesoporous supports (SAMMS™) are hybrid materials created from attachment of organic moieties onto very high surface area mesoporous silica. SAMMS with surface chemistries including three isomers of hydroxypyridinone, diphosphonic acid, acetamide phosphonic acid, glycinyl urea, and diethylenetriamine pentaacetate (DTPA) analog were evaluated for chelation of actinides (239Pu, 241Am, uranium, thorium) from blood. Direct blood decorporation using sorbents does not have toxicity or renal challenges associated with traditional chelation therapy and may have potential applications for critical exposure cases, reduction of nonspecific dose during actinide radiotherapy, and for sorbent hemoperfusion in renal insufficient patients, whose kidney clear radionuclides at very slow rate. Sorption affinity (Kd), sorption rate, selectivity, and stability of SAMMS were measured in batch contact experiments. An isomer of hydroxypyridinone (3,4-HOPO) on SAMMS demonstrated the highest affinity for all four actinides from blood and plasma and greatly outperformed the DTPA analog on SAMMS and commercial resins. In batch contact, a fifty percent reduction of actinides in blood was achieved within minutes, and there was no evidence of protein fouling or material leaching in blood after 24 hr. The engineered form of SAMMS (bead format) was further evaluated in a 100-fold scaled-down hemoperfusion device and showed no blood clotting after 2 hr. A 0.2 g quantity of SAMMS could reduce 50 wt.% of 100 ppb uranium in 50 mL of plasma in 18 min and that of 500 dpm mL?1 in 24 min. 3,4-HOPO-SAMMS has a long shelf-life in air and at room temperature for at least 8 years, indicating its feasibility for stockpiling in preparedness for an emergency. The excellent efficacy and stability of SAMMS materials in complex biological matrices suggest that SAMMS can also be used as orally administered drugs and for wound decontamination. By changing the organic groups of SAMMS, they can be used not only for actinides but also for other radionuclides. By using the mixture of these SAMMS materials, broad spectrum decorporation of radionuclides is very feasible.

Yantasee, Wassana; Sangvanich, Thanapon; Creim, Jeffery A; Pattamakomsan, Kanda; Wiacek, Robert J; Fryxell, Glen E; Addleman, R Shane; Timchalk, Charles

2010-01-01

145

Functional sorbents for selective capture of plutonium, americium, uranium, and thorium in blood.  

PubMed

Self-assembled monolayer on mesoporous supports (SAMMS) are hybrid materials created from attachment of organic moieties onto very high surface area mesoporous silica. SAMMS with surface chemistries including three isomers of hydroxypyridinone, diphosphonic acid, acetamide phosphonic acid, glycinyl urea, and diethylenetriamine pentaacetate (DTPA) analog were evaluated for chelation of actinides ((239)Pu, (241)Am, uranium, thorium) from blood. Direct blood decorporation using sorbents does not have the toxicity or renal challenges associated with traditional chelation therapy and may have potential applications for critical exposure cases, reduction of nonspecific dose during actinide radiotherapy, and for sorbent hemoperfusion in renal insufficient patients, whose kidneys clear radionuclides at a very slow rate. Sorption affinity (K(d)), sorption rate, selectivity, and stability of SAMMS were measured in batch contact experiments. An isomer of hydroxypyridinone (3,4-HOPO) on SAMMS demonstrated the highest affinity for all four actinides from blood and plasma and greatly outperformed the DTPA analog on SAMMS and commercial resins. In batch contact, a fifty percent reduction of actinides in blood was achieved within minutes, and there was no evidence of protein fouling or material leaching in blood after 24 h. The engineered form of SAMMS (bead format) was further evaluated in a 100-fold scaled-down hemoperfusion device and showed no blood clotting after 2 h. A 0.2 g quantity of SAMMS could reduce 50 wt.% of 100 ppb uranium in 50 mL of plasma in 18 min and that of 500 dpm mL(-1) in 24 min. 3,4-HOPO-SAMMS has a long shelf-life in air and at room temperature for at least 8 y, indicating its feasibility for stockpiling in preparedness for an emergency. The excellent efficacy and stability of SAMMS materials in complex biological matrices suggest that SAMMS can also be used as orally administered drugs and for wound decontamination. By changing the organic groups of SAMMS, they can be used not only for actinides but also for other radionuclides. By using the mixture of these SAMMS materials, broad spectrum decorporation of radionuclides is very feasible. PMID:20699706

Yantasee, Wassana; Sangvanich, Thanapon; Creim, Jeffery A; Pattamakomsan, Kanda; Wiacek, Robert J; Fryxell, Glen E; Addleman, R Shane; Timchalk, Charles

2010-09-01

146

Process for uranium separation and preparation of UOâ. 2NHâ. 2HF. [Effluents from UFâ. -->. UOâ conversion  

Microsoft Academic Search

A process for treating the aqueous effluents that are produced in converting gaseous UFâ (uranium hexafluoride) into solid UOâ (uranium dioxide) by way of an intermediate (NHâ)â UOâ (COâ)â (''AUC'' Compound) is disclosed. These effluents, which contain large amounts of NHâ\\/sup +\\/, COâ\\/sup 2 -\\/, F⁻, and a small amount of U are mixed with HâSOâ (sulfuric acid) in order

Dokuzoguz

1976-01-01

147

Cell adsorption and selective desorption for separation of microbial cells by using chitosan-immobilized silica.  

PubMed

Cell adsorption and selective desorption for separation of microbial cells were conducted by using chitosan-immobilized silica (CIS). When chitosan was immobilized onto silica surfaces with glutaraldehyde, bacterial cells adsorbed well and retained viability. Testing of the adsorption and desorption ability of CIS using various microbes such as Escherichia coli, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus casei, Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Saccharomyces cerevisiae, Saccharomyces ludwigii, and Schizosaccharomyces pombe revealed that most microbes could be adsorbed and selectively desorbed under different conditions. In particular, recovery was improved when L-cysteine was added. A mixture of two bacterial strains adsorbed onto CIS could also be successfully separated by use of specific solutions for each strain. Most of the desorbed cells were alive. Thus, quantitative and selective fractionation of cells is readily achievable by employing chitosan, a known antibacterial material. PMID:16332887

Kubota, Munehiro; Matsui, Masayoshi; Chiku, Hiroyuki; Kasashima, Nobuyuki; Shimojoh, Manabu; Sakaguchi, Kengo

2005-12-01

148

Strategy for selection of methods for separation of bioparticles from particle mixtures.  

PubMed

The desired product of bioprocesses is often produced in particulate form, either as an inclusion body (IB) or as a crystal. Particle harvesting is then a crucial and attractive form of product recovery. Because the liquid phase often contains other bioparticles, such as cell debris, whole cells, particulate biocatalysts or particulate by-products, the recovery of product particles is a complex process. In most cases, the particulate product is purified using selective solubilization or extraction. However, if selective particle recovery is possible, the already high purity of the particles makes this downstream process more favorable. This work gives an overview of typical bioparticle mixtures that are encountered in industrial biotechnology and the various driving forces that may be used for particle-particle separation, such as the centrifugal force, the magnetic force, the electric force, and forces related to interfaces. By coupling these driving forces to the resisting forces, the limitations of using these driving forces with respect to particle size are calculated. It shows that centrifugation is not a general solution for particle-particle separation in biotechnology because the particle sizes of product and contaminating particles are often very small, thus, causing their settling velocities to be too low for efficient separation by centrifugation. Examples of such separation problems are the recovery of IBs or virus-like particles (VLPs) from (microbial) cell debris. In these cases, separation processes that use electrical forces or fluid-fluid interfaces show to have a large potential for particle-particle separation. These methods are not yet commonly applied for large-scale particle-particle separation in biotechnology and more research is required on the separation techniques and on particle characterization to facilitate successful application of these methods in industry. PMID:16570310

van Hee, P; Hoeben, M A; van der Lans, R G J M; van der Wielen, L A M

2006-07-01

149

Method for converting uranium oxides to uranium metal  

DOEpatents

A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixtures is then cooled to a temperature less than -100/sup 0/C in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

Duerksen, W.K.

1987-01-01

150

Method for converting uranium oxides to uranium metal  

DOEpatents

A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

Duerksen, Walter K. (Norris, TN) [Norris, TN

1988-01-01

151

Ultrathin self-assembled anionic polymer membranes for superfast size-selective separation  

NASA Astrophysics Data System (ADS)

Nanoporous membranes with superior separation performance have become more crucial with increasing concerns in functional nanomaterials. Here novel ultrahigh permeable nanoporous membranes have been fabricated on macroporous supports by self-assembly of anionic polymer on copper hydroxide nanostrand templates in organic solution. This facile approach has a great potential for the fabrication of ultrathin anionic polymer membranes as a general method. The as-fabricated self-assembled membranes have a mean pore size of 5-12 nm and an adjustable thickness as low as 85 nm. They allow superfast permeation of water, and exhibit excellent size-selective separation properties and good fouling resistance for negatively-charged solutes during filtration. The 85 nm thick membrane has an ultrahigh water flux (3306 l m-2 h-1 bar-1) that is an order of magnitude larger than commercial membranes, and can highly efficiently separate 5 and 15 nm gold nanoparticles from their mixtures. The newly developed nanoporous membranes have a wide application in separation and purification of biomacromolecules and nanoparticles.Nanoporous membranes with superior separation performance have become more crucial with increasing concerns in functional nanomaterials. Here novel ultrahigh permeable nanoporous membranes have been fabricated on macroporous supports by self-assembly of anionic polymer on copper hydroxide nanostrand templates in organic solution. This facile approach has a great potential for the fabrication of ultrathin anionic polymer membranes as a general method. The as-fabricated self-assembled membranes have a mean pore size of 5-12 nm and an adjustable thickness as low as 85 nm. They allow superfast permeation of water, and exhibit excellent size-selective separation properties and good fouling resistance for negatively-charged solutes during filtration. The 85 nm thick membrane has an ultrahigh water flux (3306 l m-2 h-1 bar-1) that is an order of magnitude larger than commercial membranes, and can highly efficiently separate 5 and 15 nm gold nanoparticles from their mixtures. The newly developed nanoporous membranes have a wide application in separation and purification of biomacromolecules and nanoparticles. Electronic supplementary information (ESI) available: Synthesis and characterization of SPEK-C; effect of the sulfonation degree on membrane formation; structure and properties of the self-assembled membranes; separation of cyt.c by the self-assembled membranes; size-selective separation of gold nanoparticles by the self-assembled membranes; comparison with commercial flat sheet ultrafiltration membranes. See DOI: 10.1039/c3nr03362g

Deng, Chao; Zhang, Qiu Gen; Han, Guang Lu; Gong, Yi; Zhu, Ai Mei; Liu, Qing Lin

2013-10-01

152

Adsorbate shape selectivity: Separation of the HF/134a azeotrope over carbogenic molecular sieve  

SciTech Connect

Experimental evidence is provided for adsorptive shape selectivity in the separation of the azeotrope between HF and 1,1,1,2-tetrafluoroethane (134a) over pyrolyzed poly(furfuryl alcohol)-derived carbogenic molecular sieve (PPFA-CMS). The separation can be accomplished over coconut charcoal or Carbosieve G on the basis of the differences in the extent of equilibrium adsorption of HF and 134a. On these adsorbents 134a is more strongly bound than HF, thus it elutes much more slowly from the bed. The heat of adsorption for 134a in the vicinity of 200 C on Carbosieve G is {approximately}8.8 kcal/mol. In contrast, when the same azeotropic mixture is separated over PPFA-CMS prepared at 500 C, 134a is not adsorbed. As a result 134a elutes from the bed first, followed by HF. The reversal is brought about by the narrower pore size and pore size distribution of the PPFA-CMS versus that for Carbosieve G. Thus the separation over PPFA-CMS is an example of adsorbate shape selectivity and represents a limiting case of kinetic separation.

Hong, A.; Mariwala, R.K.; Kane, M.S.; Foley, H.C. [Univ. of Delaware, Nework, DE (United States)

1995-03-01

153

Selective separation of similarly sized proteins with tunable nanoporous block copolymer membranes.  

PubMed

An integral asymmetric membrane was fabricated in a fast and one-step process by combining the self-assembly of an amphiphilic block copolymer (PS-b-P4VP) with nonsolvent-induced phase separation. The structure was found to be composed of a thin layer of densely packed highly ordered cylindrical channels with uniform pore sizes perpendicular to the surface on top of a nonordered sponge-like layer. The as-assembled membrane obtained a water flux of more than 3200 L m(-2) h(-1) bar(-1), which was at least an order of magnitude higher than the water fluxes of commercially available membranes with comparable pore sizes, making this membrane particularly well suited to size-selective and charge-based separation of biomolecules. To test the performance of the membrane, we conducted diffusion experiments at the physiological pH of 7.4 using bovine serum albumin (BSA) and globulin-?, two proteins with different diameters but too close in size (2-fold difference in molecular mass) to be efficiently separated via conventional dialysis membrane processes. The diffusion rate differed by a factor of 87, the highest value reported to date. We also analyzed charge-based diffusive transport and separation of two proteins of similar molecular weight (BSA and bovine hemoglobin (BHb)) through the membrane as a function of external pH. The membrane achieved a selectivity of about 10 at pH 4.7, the isoelectric point (pI) of BSA. We then positively charged the membrane to improve the separation selectivity. With the modified membrane BSA was completely blocked when the pH was 7.0, the pI of BHb, while BHb was completely blocked at pH 4.7. Our results demonstrate the potential of our asymmetric membrane to efficiently separate biological substances/pharmaceuticals in bioscience, biotechnology, and biomedicine applications. PMID:23252799

Qiu, Xiaoyan; Yu, Haizhou; Karunakaran, Madhavan; Pradeep, Neelakanda; Nunes, Suzana P; Peinemann, Klaus-Viktor

2013-01-22

154

Large-Flow-Area Flow-Selective Liquid/Gas Separator  

NASA Technical Reports Server (NTRS)

This liquid/gas separator provides the basis for a first stage of a fuel cell product water/oxygen gas phase separator. It can separate liquid and gas in bulk in multiple gravity environments. The system separates fuel cell product water entrained with circulating oxygen gas from the outlet of a fuel cell stack before allowing the gas to return to the fuel cell stack inlet. Additional makeup oxygen gas is added either before or after the separator to account for the gas consumed in the fuel cell power plant. A large volume is provided upstream of porous material in the separator to allow for the collection of water that does not exit the separator with the outgoing oxygen gas. The water then can be removed as it continues to collect, so that the accumulation of water does not impede the separating action of the device. The system is designed with a series of tubes of the porous material configured into a shell-and-tube heat exchanger configuration. The two-phase fluid stream to be separated enters the shell-side portion of the device. Gas flows to the center passages of the tubes through the porous material and is then routed to a common volume at the end of the tubes by simple pressure difference from a pumping device. Gas flows through the porous material of the tubes with greater ease as a function of the ratio of the dynamic viscosity of the water and gas. By careful selection of the dimensions of the tubes (wall thickness, porosity, diameter, length of the tubes, number of the tubes, and tube-to-tube spacing in the shell volume) a suitable design can be made to match the magnitude of water and gas flow, developed pressures from the oxygen reactant pumping device, and required residual water inventory for the shellside volume.

Vasquez, Arturo; Bradley, Karla F.

2010-01-01

155

Selective Separation of Rare Earth Metals by Solvent Extraction in the Presence of New Hydrophilic Chelating Polymers Functionalized with Ethylenediaminetetraacetic Acid. II. Separation Properties by Solvent Extraction  

Microsoft Academic Search

The selective separation of rare earth metals by solvent extraction including chelating polymers in the aqueous phase was investigated. The chelating polymers were synthesized in this laboratory by introducing ethylenediaminetetraacetic acid (EDTA) onto water-soluble polyallylamine. The highest selectivity obtained for the Y\\/Er separation system was 14.7, which was much higher than that in conventional solvent extraction (about 1.4) and also

HIDETO MATSUYAMA; YOSHIKAZU MIYAMOTO; MASAAKI TERAMOTO; MASAHIRO GOTO; FUMIYUKI NAKASHIO

1996-01-01

156

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Paducah Gaseous Diffusion Plant site  

SciTech Connect

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. The U-AVLIS process is based on electrostatic extraction of photoionized U-235 atoms from an atomic vapor stream created by electron-beam vaporization of uranium metal alloy. The U-235 atoms are ionized when precisely tuned laser light -- of appropriate power, spectral, and temporal characteristics -- illuminates the uranium vapor and selectively photoionizes the U-235 isotope. A programmatic document for use in screening DOE site to locate a U-AVLIS production plant was developed and implemented in two parts. The first part consisted of a series of screening analyses, based on exclusionary and other criteria, that identified a reasonable number of candidate sites. These sites were subjected to a more rigorous and detailed comparative analysis for the purpose of developing a short list of reasonable alternative sites for later environmental examination. This environmental site description (ESD) provides a detailed description of the PGDP site and vicinity suitable for use in an environmental impact statement (EIS). The report is based on existing literature, data collected at the site, and information collected by Argonne National Laboratory (ANL) staff during a site visit. 65 refs., 15 tabs.

Marmer, G.J.; Dunn, C.P.; Moeller, K.L.; Pfingston, J.M.; Policastro, A.J.; Yuen, C.R.; Cleland, J.H. (ed.)

1991-09-01

157

Separation of Selected Bile Acids by TLC. IV. Comparison of Separation of Studied Bile Acids by the Use of Cluster Analysis  

Microsoft Academic Search

Selected bile acids such as cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC) were separated on both, silica gel and a mixture of silica gel 60 and Kieselguhr F254 by using adsorption thin?layer chromatography. The similar analyses were used to compare the separations of studied bile

A. Pyka; M. Dolowy

2005-01-01

158

Uranium hexafluoride handling. Proceedings  

SciTech Connect

The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

Not Available

1991-12-31

159

Gas Separation Using Organic-Vapor-Resistent Membranes In Conjunctin With Organic-Vapor-Selective Membranes  

DOEpatents

A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

Baker, Richard W. (Palo Alto, CA); Pinnau, Ingo (Palo Alto, CA); He, Zhenjie (Fremont, CA); Da Costa, Andre R. (Menlo Park, CA); Daniels, Ramin (San Jose, CA); Amo, Karl D. (Mountain View, CA); Wijmans, Johannes G. (Menlo Park, CA)

2003-06-03

160

Selective Separation and Determination of Heavy Metals (Cd, Pb, Cr) Speciation Forms from Hortic Antrosols  

NASA Astrophysics Data System (ADS)

The speciation, inter-phases distribution and biodisponibility of heavy metals in soils represent one of main problem of environmental geochemistry and agro-chemistry. This problem is very important in case of hortic antrosols (soils from glasshouses) for the elimination of agricultural products (fruits, vegetables) contamination with heavy metals. In soils from glass houses, the speciation and inter-phases distribution processes of heavy metals have a particular dynamic, different in comparison with those from non-protected soils. The predominant distribution forms of heavy metals in such soils types are: complexes with low mass organic molecules, organic-mineral complexes, complexes with inorganic ligands (hydroxide-complexes, carbonate-complexes, sulphate-complexes, etc.) and basic salts. All of these have high stabilities in conditions of soils from glass houses, and in consequence, the separation and determination of speciation forms (which is directly connected with biodisponibility of heavy metals) by usual methods id very difficult and has a high uncertain degree. In this study is presented an original method for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils, which is based by the combination of solid-liquid sequential extraction (SPE) with the extraction in aqueous polymer-inorganic salt two-phase systems (ABS). The soil samples used for this study have been sampled from three different locations (glass houses from Iasi, Barlad and Bacau - Romania) where the vegetables cultivation have bee performed by three different technologies. In this way was estimated the applicability and the analytical limits of method proposed by as, in function of the chemical-mineralogical and physical-chemical characteristics of soils. As heavy metals have been studied cadmium, lead and chromium, all being known for their high toxicity. The procedure used for the selective separation and differentiation of speciation forms of heavy metals from glass houses soils has two main steps: (i) non-destructive separation of chemical-mineralogical associations and aggregates from soils samples - for this the separation method with heavy liquids (bromophorme) and isodynamic magnetic method have been used; (ii) sequential extraction of heavy metals from soil fractions separated in the first step, by using combined SPE-ABS procedure. For the preparation of combined extraction systems was used polyethylene glycol (with different molecular mass: 2000, 4000 and 8000). As phase-forming inorganic salts and as selective extracting agents we have used different usual inorganic reagents. The type and concentration of phase-forming salts have been selected in function of, both nature of extracted heavy metals and chemical-mineralogical characteristics of soil samples. The experimental parameters investigated in this study are: molecular mass of polyethylene glycol and the concentration of polymeric solutions, nature and concentration of phase-forming salts, nature and concentration of extracting agents, pH in extraction system phase, type of extracted heavy metals, type of speciation forms of heavy metals and their concentrations. All these factors can influence significantly the efficiency and the selectivity of separation process. The experimental results have indicate that the combined SPE-ABS extraction systems have better separation efficiency, in comparison with traditional SPE systems and ca realized a accurate discrimination between speciation forms of heavy metals from soils. Under these conditions, the estimation of inter-phases distribution and biodisponibility of heavy metals has a high precision. On the other hand, when the combined SPE-ABS systems are used, the concomitant extraction of the elements from the same geochemical association with studied heavy metals (inevitable phenomena in case of separation by SPE procedures) is significant diminished. This increases the separation selectivity and facilitated the more accurate determination of speciation forms concentration. By adequat

Bulgariu, D.; Bulgariu, L.

2009-04-01

161

The Use of Polyacrylamide as a Selective Depressant in the Separation of Chalcopyrite and Galena  

NASA Astrophysics Data System (ADS)

High molecular weight polyacrylamide (PAM) was tested as a potential selective depressant in the differential flotation separation of galena and chalcopyrite using potassium ethyl xanthate (KEX) as a collector. In single mineral flotation, PAM depressed chalcopyrite while galena was floatable. Mechanism study indicated that PAM could adsorb on galena through hydrogen bonding, and on chalcopyrite through hydrogen bonding as well as ammonium-copper complexation. KEX could only break up the galena-PAM bonding. It is the combined use of PAM and KEX that caused the selectivity. In mineral mixture flotation, galena and chalcopyrite could be separated by PAM and KEX only after EDTA treatment of the mineral mixtures. Time of flight secondary ion mass spectrometric (ToF-SIMS) measurements indicated that when galena and chalcopyrite were present together in the suspension, PAM adsorbed on both galena and chalcopyrite. However, after prior treatment of the mineral mixture by EDTA, PAM mainly adsorbed on chalcopyrite.

Wang, Lei

162

Selective Separation of Normal Paraffins from Slack Wax Using the Molecular Sieve Adsorption Technique  

Microsoft Academic Search

The selective separation of heavy n?paraffins (C20–C30) from refinery slack wax was performed by adsorption onto zeolite molecular sieves (5A). Sorbents were characterized by thermogravimetric analyses, N2 adsorption, and mercury porosimetry. Three slack waxes: light, medium and heavy, were used, being analyzed by gas chromatography (GC) and simulated distillation. Several tests were carried out in a stirred batch reactor at

L. A. Angosto Olmos; M. A. Muñecas Vidal

2005-01-01

163

Use of Structural Descriptors to QSRR Analysis of Selected Bile Acids Separated by NP-TLC  

Microsoft Academic Search

The selected bile acids such as: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), lithocholic acid (LC), were separated by using normal phase thin-layer chromatography (NP-TLC) on glass plates precoated with silica gel 60 with concentrating zone (E. Merck, #1.11845) and n-hexane-ethyl acetate–methanol-acetic acid in volume composition 20:20:5:2 as the

Alina Pyka

2009-01-01

164

Novel syntergistic agent for selective separation of yttrium from other rare earth metals  

SciTech Connect

An oil-soluble synergistic agent has been developed for the selective separation of yttrium (Y) from the other rare earth metals. The synergistic agent is a polyaminocarboxylic acid alkylderivative and has interfacial activity like that of surfactants. Separation of yttrium from heavy rare earth metals (erbium (Er) and holmium (Ho)) in the presence of the synergistic agent was carried out with a 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester as a carrier using a hollow-fiber membrane extractor. The new agent shows a synergistic effect on the permeation rate of rare earth metals at the oil-water interface. By the addition of a small amount of the agent, the selectivity for yttrium from the two rare earth metals was enhanced remarkably, because of the permeation rate of Y was selectively decreased compared with those of Er and Ho. The synergistic effect is discussed from the viewpoint of the stability constant for rare earth metals and the interfacial activity of the synergistic agent. The difference in interaction between the synergistic agent and rare earth ions at the oil-water interface results in an increase in the separation efficiency.

Miyata, Terufumi; Goto, Masahiro; Nakashio, Fumiyuki [Kyushu Univ., Fukuoka (Japan)

1995-06-01

165

Flame treatment for the selective wetting and separation of PVC and PET  

SciTech Connect

Flame treatment has been used for many years to modify the surface of plastics to allow coatings to be added. The effect of the treatment is to produce hydrophilic species on the surface of the plastic making it water-wettable. The production of hydrophilic plastic surfaces is also required in the selective separation of plastics by froth flotation. For the process to be selective one plastic must be rendered hydrophilic while another remains hydrophobic. In this study the potential for separation of PVC and PET has been investigated. Flame treatment was shown to be very effective in producing a hydrophilic surface on both plastics, although the process was not selective under the conditions investigated. Raising the temperature of the plastics above their softening point produced a hydrophobic recovery. As the softening point of PVC was significantly lower than for PET it was possible to produce a significant difference in hydrophobicity, as judged using contact angle measurement. When immersed in water the contact angle of the PVC was found to be strongly dependent on the pH. Good separation efficiency of the two plastics was achieved by froth flotation from pH 4 to 9. One particular advantage of the technique is that no chemical reagents may be required in the flotation stage. The practicalities of designing a flake treatment system however have to be addressed before considering it to be a viable industrial process.

Pascoe, R.D.; O'Connell, B

2003-07-01

166

Selective separation of virgin and post-consumer polymers (PET and PVC) by flotation method  

SciTech Connect

More and more polymer wastes are generated by industry and householders today. Recycling is an important process to reduce the amount of waste resulting from human activities. Currently, recycling technologies use relatively homogeneous polymers because hand-sorting waste is costly. Many promising technologies are being investigated for separating mixed thermoplastics, but they are still uneconomical and unreliable. At present, most waste polymers cause serious environmental problems. Burning polymers for recycling is not practiced since poisonous gases are released during the burning process. Particularly, polyvinyl chloride (PVC) materials among waste polymers generate hazardous HCl gas, dioxins containing Cl, etc., which lead to air pollution and shorten the life of the incinerator. In addition, they make other polymers difficult to recycle. Both polyethylene terephthalate (PET) and PVC have densities of 1.30-1.35 g/cm{sup 3} and cannot be separated using conventional gravity separation techniques. For this reason, polymer recycling needs new techniques. Among these techniques, froth flotation, which is also used in mineral processing, can be useful because of its low cost and simplicity. The main objective of this research is to recycle PET and PVC selectively from post-consumer polymer wastes and virgin polymers by using froth flotation. According to the results, all PVC particles were floated with 98.8% efficiency in virgin polymer separation while PET particles were obtained with 99.7% purity and 57.0% efficiency in post-consumer polymer separation.

Burat, Firat; Gueney, Ali [Istanbul Technical University, Faculty of Mines, Mineral Processing Engineering Department, 34469 Maslak, Istanbul (Turkey); Olgac Kangal, M. [Istanbul Technical University, Faculty of Mines, Mineral Processing Engineering Department, 34469 Maslak, Istanbul (Turkey)], E-mail: kangal@itu.edu.tr

2009-06-15

167

Selective recognition and separation of nucleosides using carboxymethyl-?-cyclodextrin functionalized hybrid magnetic nanoparticles.  

PubMed

A novel magnetic nanoadsorbent (CMCD-APTS-MNPs) containing the superparamagnetic and molecular recognition properties was synthesized by grafting carboxymethyl-?-cyclodextrin (CM-?-CD) on 3-aminopropyltriethoxysile (APTS) modified Fe(3)O(4) nanoparticles. The feasibility of using CMCD-APTS-MNPs as magnetic nanoadsorbent for selective adsorption of adenosine (A) and guanosine (G) based on inclusion and molecular recognition was demonstrated. The as-synthesized magnetic nanoparticles were characterized by TEM, FTIR and TGA analyses. The effects of pH and initial nucleoside concentrations on the adsorption behavior were studied. The complexation of CMCD-APTS-MNPs with both nucleosides was found to follow the Langmuir adsorption isotherm. The CMCD-APTS-MNPs showed a higher adsorption ability and selectivity for G than A under identical experimental conditions, which results from the ability of selective binding and recognition of the immobilized CM-?-CD towards G. The driving force of the separation between G and A is through the different weak interaction with grafted CM-?-CD, i.e., hydrogen bond interaction, which is evidenced by different inclusion equilibrium constants and FTIR analyses of inclusion complexes between grafted cyclodextrin and the guest molecules. Our results indicated that this nanoadsorbent would be a promising tool for easy, fast and selective separation, analysis of nucleosides and nucleotides in biological samples. PMID:22177539

Badruddoza, A Z M; Junwen, L; Hidajat, K; Uddin, M S

2012-04-01

168

Selectivity in preparative separations of inorganic electrolytes by size-exclusion chromatography on hypercrosslinked polystyrene and microporous carbons  

Microsoft Academic Search

Preparative-scale separation of concentrated solutions of simplest mineral electrolytes by size-exclusion chromatography was performed on three samples of commercially available microporous hypercrosslinked polystyrene sorbents “Macronet Hypersol” and two experimental samples of activated carbons. Selectivity of separation of a pair of electrolytes was found to be determined by the largest ions in each pair. Fortunately, selectivity rises at higher concentrations of

V. A. Davankov; M. P. Tsyurupa; N. N. Alexienko

2005-01-01

169

Synthesis of magnetic ion-imprinted composites and selective separation and preconcentration of U(VI).  

PubMed

The U(VI) magnetic ion-imprinted composite (MIIC) with a uniform core-shell structure for the selective separation and preconcentration of U(VI) was prepared by copolymerization of a ternary complex of uranyl ions with 4-vinylpyridine (4-VP) and acrylamide in the presence of 2,2'-azobisisobutyronitrile. The sorption of U(VI) on the MIIC from aqueous solution was evaluated. The maximum sorption capacity of MIIC for U(VI) was 354.85 mg g(-1), which was much higher than that of the magnetic nonimprinted composite. The MIIC could be recovered by desorbing the U(VI)-loaded MIIC with 0.5 mol L(-1) HNO3, and the surface morphology of MIIC after five consecutive sorption/desorption cycles was significantly damaged. The competitive sorption experiments showed that the MIIC had a desirable selectivity for U(VI) over a range of competing metal ions. The MIIC may be a promising sorbent material for the selective separation and preconcentration of U(VI). PMID:24667936

Liu, Mancheng; Chen, Changlun; Wen, Tao; Wang, Xiangke

2014-05-21

170

Imprint-coating synthesis of selective functionalized ordered mesoporous sorbents for separation and sensors  

DOEpatents

The present invention relates generally to mesoporous sorbent materials having high capacity, high selectivity, fast kinetics, and molecular recognition capability. The invention also relates to a process for preparing these mesoporous substrates through molecular imprinting techniques which differ from convention techniques in that a template molecule is bound to one end of bifunctional ligands to form a complex prior to binding of the bifunctional ligands to the substrate. The present invention also relates to methods of using the mesoporous sorbent materials, for example, in the separation of toxic metals from process effluents, paints, and other samples; detection of target molecules, such as amino acids, drugs, herbicides, fertilizers, and TNT, in samples; separation and/or detection of substances using chromatography; imaging agents; sensors; coatings; and composites.

Dai, Sheng (Knoxville, TN) [Knoxville, TN; Burleigh, Mark C. (Lenoir City, TN) [Lenoir City, TN; Shin, Yongsoon (Richland, WA) [Richland, WA

2001-01-01

171

Appraisal of selected epidemiologic issues from studies of lung cancer among uranium and hard rock miners  

SciTech Connect

An extensive body of published information about lung cancer among uranium miners was reviewed and diverse information, useful in identifying important issues but not in resolving them was found. Measuring exposure and response; thresholds of exposure; latency or the period from first mining experience to death; effort to predict excess risk of death, using a model; effects of smoking and radon daughter exposure on the histology of lung tumors; and the interplay of factors on the overall risk of death were all examined. The general concept of thresholds; that is, an exposure level below which risk does not increase was considered. The conclusion is that it should be possible to detect and estimate an epidemiologic threshold when the cohorts have been followed to the death of all members. Issues concerning latency in the studies of uranium miners published to date were examined. It is believed that the induction-latent period for lung cancer among uranium miners may be: as little as 10 to more than 40 years; dependent on age at which exposure begins; exposure rate; and ethnicity or smoking habits. Although suggested as factual, their existence is uncertain. An effect due to the exposure rate may exist although it has not been factual, their existence is uncertain. An effect due to the exposure rate may exist although it has not been confirmed. The median induction-latent period appears to be in excess of the 15 years frequently cited for US uranium miner. A distinct pattern of shorter induction-latent periods with increasing age at first mining exposure is reported. The evidence for and against an unusual histologic pattern of lung cancers among uranium miners was examined. The ratio of epidermoid to small cell types was close to 1:2; the ratio in the general population is nearer 2:1. The histologic pattern warrants closer attention of pathologists and epidemiologists. (ERB) (ERB)

Petersen, G.R.; Sever, L.E.

1982-04-01

172

Uranium extraction selectivities of dibutyl carbitol and tributyl phosphate in the system UOâ(NOâ)â-HNOâ-HâO-Al(NOâ)â-solvent  

Microsoft Academic Search

Historically, both the BUTEX (dibutyl carbitol-based) and PUREX (tributyl phosphate-based) processes have been used for uranium recovery and purification. Currently, BUTEX- and PUREX-type extraction processes are being used in series for recovery of isotopically enriched uranium at the Oak Ridge Y-12 Plant. The use of two solvents is predicated on the differing selectivities of each with regard to the contaminant

Birdwell

1999-01-01

173

Sulfate Separation from Aqueous Alkaline Solutions by Selective Crystallization of Alkali Metal Coordination Capsules  

SciTech Connect

Self-assembly of a tris(urea) anion receptor with Na{sub 2}SO{sub 4} or K{sub 2}SO{sub 4} yields crystalline capsules held together by coordinating Na{sup +} or K{sup +} cations and hydrogen-bonding water bridges, with the sulfate anions encapsulated inside urea-lined cavities. The sodium-based capsules can be selectively crystallized in excellent yield from highly competitive aqueous alkaline solutions ({approx}6 M Na{sup +}, pH 14), thereby providing for the first time a viable approach to sulfate separation from nuclear wastes.

Rajbanshi, Arbin [Oak Ridge National Laboratory (ORNL); Moyer, Bruce A [ORNL; Custelcean, Radu [ORNL

2011-01-01

174

The influence of the organic modifier in hydro-organic mobile phase on separation selectivity of steroid hormones separation using cholesterol-bonded stationary phases.  

PubMed

Chromatographic properties of four cholesterol bonded phases with different structures were studied. The columns used were packed with a stationary phase containing a cholesterol molecule attached to the silica surface using different types of linkage molecules. Columns were compared according to the retention and separation selectivity of steroid hormones. The measurements were done using binary hydro-organic mobile phases with methanol, ethanol and acetonitrile as an organic modifier. The presented results show that the coverage density of the bonded ligands and the type of organic modifier strongly influence the retention mechanism and separation selectivity of steroid hormones on cholesterol-containing adsorbents. PMID:22658299

Bocian, Szymon; Soukup, Jan; Matyska, Maria; Pesek, Joseph; Jandera, Pavel; Buszewski, Bogus?aw

2012-07-01

175

Application of topological indexes for evaluation of the TLC separation of selected essential oil components.  

PubMed

The selected essential oil components (menthol, (+)bomeol, geraniol, linalool, carvone, camphor, (IR)-(-)fenchone) were separated by adsorption thin-layer chromatography using benzene as mobile phase. Investigated terpenes were characterized by selected topological indexes based on the adjacency and distance matrix. From among all the topological indexes counted only Si(o) index (the sum of the distance between the oxygen atom and all the remaining atoms in graph) as well as cluster Randi? indexes (4chi(c), and 4chi(v)c) allow for estimation of the chromatograms obtained. With the fact mentioned above, there exists the possibility of prediction of relative situation on a chromatogram of the terpenes investigated. For the rest of topological indexes that possibility was not stated. PMID:12365610

Pyka, Alina; Bober, Katarzyna; Gurak, Danuta; Niestroj, Anna

2002-01-01

176

Separating Metallic Beryllium from Plutonium by Selective Dissolution with Ammonium Fluoride  

SciTech Connect

Plutonium metal is stabilized for long-term storage by calcining to produce PuO{sub 2}. However, if beryllium is present, the calcined product may have a high neutron dose rate because of the {sup 9}Be({alpha},n){sup 12}C reaction in the finely divided oxide mixture. (At LLNL, inadvertent calcining of a mixture of {approx}500 g Pu/50 g Be produced a neutron source of {approx}5 R/hr.) Therefore, for health physics reasons, we would like a convenient procedure to remove beryllium from plutonium with high selectivity. Two reagents, sodium hydroxide and ammonium fluoride, were considered for aqueous processing. Each reagent selectively dissolves beryllium, which can be separated from the insoluble plutonium by decanting/filtering operations followed by water washes to remove the excess reagent. The washed plutonium is calcined for storage; the beryllium and wash fractions are solidified for disposal.

Torres, R A

2006-11-29

177

Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite  

NASA Astrophysics Data System (ADS)

The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite.

Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

2014-05-01

178

Upgrading of Low-Grade Manganese Ore by Selective Reduction of Iron Oxide and Magnetic Separation  

NASA Astrophysics Data System (ADS)

The utilization of low-grade manganese ores has become necessary due to the intensive mining of high-grade ores for a long time. In this study, calcined ferruginous low-grade manganese ore was selectively reduced by CO, which converted hematite to magnetite, while manganese oxide was reduced to MnO. The iron-rich component was then separated by magnetic separation. The effects of the various reduction parameters such as particle size, reduction time, temperature, and CO content on the efficiency of magnetic separation were studied by single-factor experiments and by a comprehensive full factorial experiment. Under the best experimental conditions tested, the manganese content in the ore increased from around 36 wt pct to more than 44 wt pct, and almost 50 wt pct of iron was removed at a Mn loss of around 5 pct. The results of the full factorial experiments allowed the identification of the significant effects and yielded regression equations for pct Fe removed, Mn/Fe, and pct Mn loss that characterize the efficiency of the upgrading process.

Gao, Yubo; Olivas-Martinez, M.; Sohn, H. Y.; Kim, Hang Goo; Kim, Chan Wook

2012-12-01

179

Selection and Separation of Viable Cells Based on a Cell-Lethal Assay  

PubMed Central

A method to select and separate viable cells based on the results of a cell-lethal assay was developed. Cells were plated on an array of culture sites with each site composed of closely spaced, releasable micropallets. Clonal colonies spanning multiple micropallets on individual culture sites were established within 72 h of plating. Adjacent sites were widely spaced with 100% of the colonies remaining sequestered on a single culture site during expansion. A laser-based method mechanically released a micropallet underlying a colony to segment the colony into two genetically identical colonies. One portion of the segmented colony was collected with 90% efficiency while viability of both fractions was 100%. The segmented colonies released from the array were fixed and subjected to immunofluorescence staining of intracellular phospho-ERK kinase to identify colonies that were highly resistant or sensitive to phorbol ester-induced activation of ERK. These resistant and sensitive cells were then matched to the corresponding viable colonies on the array. Sensitive and resistant colonies on the array were released and cultured. When these cultured cells were reanalyzed for phorbol ester-induced ERK activity, the cells retained the sensitive or resistant phenotype of the originally screened subcolony. Thus cells were separated and collected based using the result of a cell-lethal assay as selection criteria. These microarrays enabling clonal colony segmentation permitted sampling and manipulation of the colonies at very early times and at small cell numbers to reduce reagent, time and manpower requirements.

Xu, Wei; Herman, Annadele; Phillips, Colleen; Pai, Jeng-Hao; Sims, Christopher E.; Allbritton, Nancy L.

2010-01-01

180

In-line assay monitor for uranium hexafluoride  

DOEpatents

An in-line assay monitor for determining the content of uranium-235 in a uranium hexafluoride gas isotopic separation system is provided which removes the necessity of complete access to the operating parameters of the system for determining the uranium-235 content. The method and monitor for carrying out the method involve cooling of a radiation pervious chamber connected in fluid communication with the selected point in the system to withdraw a specimen and solidify the specimen in the chamber. The specimen is irradiated by means of an ionizing radiation source of energy different from that of the 185 keV gamma emissions from uranium-235. The uranium-235 content of the specimen is determined from comparison of the accumulated 185 keV energy counts and reference energy counts. The latter is used to measure the total uranium isotopic content of the specimen.

Wallace, S.A.

1980-03-21

181

Selective separation of rare earth metals by solvent extraction in the presence of new hyrophilic chelating polymers functionalized with ethylenediaminetetraacetic acid. II. Separation properties by solvent extraction  

SciTech Connect

The selective separation of rare earth metals by solvent extraction including chelating polymers in the aqueous phase was investigated. The chelating polymers were synthesized in this laboratory by introducing ethylenediaminetetraacetic acid (EDTA) onto water-soluble polyallylamine. The highest selectivity obtained for the Y/Er separation system was 14.7, which was much higher than that in extraction including EDTA (about 5.0). This means that the number of extraction stages required can be considerably reduced by the addition of chelating polymers. The effects of several experimental conditions such as pH, extractant concentrations, chelating polymer concentrations, and initial total rare earth metal concentrations, chelating polymer concentrations, and initial total rare earth metal concentrations on the separation factors and the distribution ratios for the Y/Er system were studied in detail. Furthermore, this extraction method was applied to other separation systems (Y/Dy, Y/Ho, Y/Tm). A remarkably high separation factor (12.6) was obtained for the Y/Tm system and the Y/Er system, although the separation factors were comparable to those in the presence of EDTA in the Y/Dy and Y/Ho systems.

Matsuyama, Hideto; Miyamoto, Yoshikazu; Teramoto, Masaaki [Kyoto Inst. of Technology, Kyoto (Japan)] [and others

1996-03-01

182

Removal of uranium from uranium-contaminated soils -- Phase 1: Bench-scale testing. Uranium in Soils Integrated Demonstration  

SciTech Connect

To address the management of uranium-contaminated soils at Fernald and other DOE sites, the DOE Office of Technology Development formed the Uranium in Soils Integrated Demonstration (USID) program. The USID has five major tasks. These include the development and demonstration of technologies that are able to (1) characterize the uranium in soil, (2) decontaminate or remove uranium from the soil, (3) treat the soil and dispose of any waste, (4) establish performance assessments, and (5) meet necessary state and federal regulations. This report deals with soil decontamination or removal of uranium from contaminated soils. The report was compiled by the USID task group that addresses soil decontamination; includes data from projects under the management of four DOE facilities [Argonne National Laboratory (ANL), Los Alamos National Laboratory (LANL), Oak Ridge National Laboratory (ORNL), and the Savannah River Plant (SRP)]; and consists of four separate reports written by staff at these facilities. The fundamental goal of the soil decontamination task group has been the selective extraction/leaching or removal of uranium from soil faster, cheaper, and safer than current conventional technologies. The objective is to selectively remove uranium from soil without seriously degrading the soil`s physicochemical characteristics or generating waste forms that are difficult to manage and/or dispose of. Emphasis in research was placed more strongly on chemical extraction techniques than physical extraction techniques.

Francis, C. W.

1993-09-01

183

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Portsmouth Gaseous Diffusion Plant site  

SciTech Connect

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. In the 1970s, the US Department of Energy (DOE) began investigating more efficient and cost-effective enrichment technologies. In January 1990, the Secretary of Energy approved a plan for the demonstration and deployment of the Uranium Atomic Vapor Laser isotope Separation (U-AVLIS) technology with the near-term goal to provide the necessary information to make a deployment decision by November 1992. Initial facility operation is anticipated for 1999. A programmatic document for use in screening DOE sites to locate a U-AVLIS production plant was developed and implemented in two parts. The first part consisted of a series of screening analyses, based on exclusionary and other criteria, that identified a reasonable number of candidate sites. The final evaluation, which included sensitivity studies, identified the Oak Ridge Gaseous Diffusion Plant (ORGDP) site, the Paducah Gaseous Diffusion Plant (PGDP) site, and the Portsmouth Gaseous Diffusion Plant (PORTS) site as having significant advantages over the other sites considered. This environmental site description (ESD) provides a detailed description of the PORTS site and vicinity suitable for use in an environmental impact statement (EIS). This report is based on existing literature, data collected at the site, and information collected by Argonne National Laboratory (ANL) staff during site visits. The organization of the ESD is as follows. Topics addressed in Sec. 2 include a general site description and the disciplines of geology, water resources, biotic resources, air resources, noise, cultural resources, land use. Socioeconomics, and waste management. Identification of any additional data that would be required for an EIS is presented in Sec. 3.

Marmer, G.J.; Dunn, C.P.; Filley, T.H.; Moeller, K.L.; Pfingston, J.M.; Policastro, A.J.; Cleland, J.H.

1991-09-01

184

Electrothermal vaporization — inductively coupled plasma-atomic emission spectrometry for trace metal determination in uranium and thorium compounds without prior matrix separation  

NASA Astrophysics Data System (ADS)

The electrothermal vaporization (ETV) mode of sample introduction into inductively coupled plasma (ICP) has been examined for its suitability for the analysis of trace metals in uranium and thorium compounds without prior chemical separation of the matrices using atomic emission spectrometry (AES). The ETV interfaced with an ICP torch adapted for glove box operation, has led to determination of sub-nanogram amounts of Al, Be, Ca, Cd, Co, Cr, Cu, Mg, Mn, Na, Ni, Zn, Dy, Eu, Gd and Sm using 10 ?l of the sample aliquot containing 200 ?g of U/Th matrix with a precision of 1-2%RSD. The results obtained here especially for rare earths in the presence of the matrix are of significance.

Purohit, Paru J.; Goyal, Neelam; Thulasidas, S. K.; Page, A. G.; Sastry, M. D.

2000-08-01

185

Rapid and selective separation for mixed proteins with thiol functionalized magnetic nanoparticles  

PubMed Central

Thiol group functionalized silica-coated magnetic nanoparticles (Si-MNPs@SH) were synthesized for rapid and selective magnetic field-based separation of mixed proteins. The highest adsorption efficiencies of binary proteins, bovine serum albumin (BSA; 66 kDa; pI = 4.65) and lysozyme (LYZ; 14.3 kDa; pI = 11) were shown at the pH values corresponding to their own pI in the single-component protein. In the mixed protein, however, the adsorption performance of BSA and LYZ by Si-MNPs@SH was governed not only by pH but also by the molecular weight of each protein in the mixed protein.

2012-01-01

186

Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells  

PubMed Central

The ganglion cell output of the retina constitutes a bottleneck in sensory processing in that ganglion cells must encode multiple stimulus parameters in their responses. Here we investigate encoding strategies of On-Off directionally selective retinal ganglion cells (On-Off DS RGCs) in rabbits, a class of cells dedicated to representing motion. The exquisite axial discrimination of these cells to preferred vs. null direction motion is well documented: it is invariant with respect to speed, contrast, spatial configuration, spatial frequency, and motion extent. However, these cells have broad direction tuning curves and their responses also vary as a function of other parameters such as speed and contrast. In this study, we examined whether the variation in responses across multiple stimulus parameters is systematic, that is the same for all cells, and separable, such that the response to a stimulus is a product of the effects of each stimulus parameter alone. We extracellularly recorded single On-Off DS RGCs in a superfused eyecup preparation while stimulating them with moving bars. We found that spike count responses of these cells scaled as independent functions of direction, speed, and luminance. Moreover, the speed and luminance functions were common across the whole sample of cells. Based on these findings, we developed a model that accurately predicted responses of On-Off DS RGCs as products of separable functions of direction, speed, and luminance (r = 0.98; P < 0.0001). Such a multiplicatively separable encoding strategy may simplify the decoding of these cells' outputs by the higher visual centers.

Nowak, Przemyslaw; Dobbins, Allan C.; Gawne, Timothy J.; Grzywacz, Norberto M.

2011-01-01

187

Southern complex: geology, geochemistry, mineralogy, and mineral chemistry of selected uranium- and thorium-rich granites  

SciTech Connect

Four major rock groups are defined in the Southern Complex: the Bell Creek Granite (BCG), the Clotted Granitoids (CGR), the Albite Granite (AGR), and the Migmatite Complex. Metatexites of the Migmatite Complex are the oldest rocks and include paleosome of a metasedimentary and metavolcanic protolith represented by Banded Iron Formation, Banded Amphibolite, and Banded Gneisses, and interlayered or crosscutting leucogranites. The CGR span the range from metatexite to diatexite and represent in-situ partial melting of metapelitic layers in the protolith during intrusion of the BCG. The BCG cuts the migmatites, is locally cut by the CGR, and was derived by partial melting of a dominantly metasedimentary protolith at some depth below the presently exposed migmatites during a regional tectonothermal event. The Albite Granite is a 2km diameter, muscovite-fluorite-columbite-bearing intrusive stock that cuts all other major units. The thorium history of the BCG is a function of the history of monazite. The thorium history of the CGR is also dominated by monazite but the thorium content of this unit cannot be entirely accounted for by original restite monazite. The uranium history of the BCG and CGR was dominated by magmatic differentiation and post magmatic, metamorphic and supergene redistributions and is largely independent of the thorium history. The thorium and uranium history of the AGR was dominated by magmatic/deuteric processes unlike the BCG and CGR.

Hoffman, M.A.

1987-01-01

188

Selection of water-dispersible carbon black for fabrication of uranium oxicarbide microspheres  

NASA Astrophysics Data System (ADS)

Fabrication of uranium oxicarbide microspheres, a component of TRISO fuel particles for high temperature nuclear power systems, is based on the internal gelation of uranium salts in the presence of carbon black. In order to obtain a high quality product, carbon black should remain dispersed during all phases of the gelation process. In this study, the surface and structural properties of several commercial carbon black materials, and the use of dispersing agents was examined with the goal of finding optimal conditions for stabilizing submicron-sized carbon black dispersions. Traditional methods for stabilizing dispersions, based on the use of dispersing agents, failed to stabilize carbon dispersions against large pH variations, typical for the internal gelation process. An alternate dispersing method was proposed, based on using surface-modified carbons functionalized with strongly ionized surface groups (sodium sulfonate). With a proper choice of surface modifiers, these advanced carbons disperse easily to particles in the range of 0.15-0.20 ?m and the dispersions remain stable during the conditions of internal gelation.

Contescu, Cristian I.; Baker, Frederick S.; Hunt, Rodney D.; Collins, Jack L.; Burchell, Timothy D.

2008-03-01

189

Assessment of the Quality of Selected EIA Data Series: Uranium and Nuclear Power Data from 1977 to 1983.  

National Technical Information Service (NTIS)

This report focuses on uranium exploration activity, uranium marketing activity, and capacity factors for nuclear power plants. These topics represented EIA's major data collections in the nuclear power area at the time this study was prepared. At the tim...

R. Miller L. E. Doman S. R. Freedman

1985-01-01

190

An evaluation of CO 2 and H 2 selective polymeric membranes for CO 2 separation in IGCC processes  

Microsoft Academic Search

The potential of CO2 and H2 selective polymeric membranes to separate CO2 from integrated coal gasification combined cycle power plants is examined. As a reference power plant a modified version of the Puertollano gasification plant has been defined. A detailed ASPEN model for the reference case has been developed. For the CO2 selective membranes single membrane module concepts as well

J. Franz; V. Scherer

2010-01-01

191

Separable Sustained and Selective Attention Factors Are Apparent in 5-Year-Old Children  

PubMed Central

In adults and older children, evidence consistent with relative separation between selective and sustained attention, superimposed upon generally positive inter-test correlations, has been reported. Here we examine whether this pattern is detectable in 5-year-old children from the healthy population. A new test battery (TEA-ChJ) was adapted from measures previously used with adults and older children and administered to 172 5-year-olds. Test-retest reliability was assessed in 60 children. Ninety-eight percent of the children managed to complete all measures. Discrimination of visual and auditory stimuli were good. In a factor analysis, the two TEA-ChJ selective attention tasks (one visual, one auditory) loaded onto a common factor and diverged from the two sustained attention tasks (one auditory, one motor), which shared a common loading on the second factor. This pattern, which suggests that the tests are indeed sensitive to underlying attentional capacities, was supported by the relationships between the TEA-ChJ factors and Test of Everyday Attention for Children subtests in the older children in the sample. It is possible to gain convincing performance-based estimates of attention at the age of 5 with the results reflecting a similar factor structure to that obtained in older children and adults. The results are discussed in light of contemporary models of attention function. Given the potential advantages of early intervention for attention difficulties, the findings are of clinical as well as theoretical interest.

Underbjerg, Mette; George, Melanie S.; Thorsen, Poul; Kesmodel, Ulrik S.; Mortensen, Erik L.; Manly, Tom

2013-01-01

192

Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption  

DOEpatents

Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon, zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high parity hydrogen from gaseous products of coal gasification and as an acid gas scrubber.

Ghate, Madhav R. (Morgantown, WV); Yang, Ralph T. (Williamsville, NY)

1987-01-01

193

Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption  

DOEpatents

Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high purity hydrogen from gaseous products of coal gasification and as an acid gas scrubber. 2 figs., 2 tabs.

Ghate, M.R.; Yang, R.T.

1985-10-03

194

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Portsmouth Gaseous Diffusion Plant site  

Microsoft Academic Search

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. In the 1970s, the US Department of Energy (DOE) began investigating more efficient and cost-effective enrichment technologies. In January 1990, the Secretary of Energy approved a plan for the demonstration and deployment of the Uranium Atomic Vapor Laser isotope

G. J. Marmer; C. P. Dunn; T. H. Filley; K. L. Moeller; J. M. Pfingston; A. J. Policastro; J. H. Cleland

1991-01-01

195

Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.  

PubMed

One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. PMID:23932372

Kifle, Dejene; Wibetoe, Grethe

2013-09-13

196

Production of separation-nozzle systems for uranium enrichment by a combination of X-ray lithography and galvanoplastics  

Microsoft Academic Search

X-ray lithography using synchrotron radiation has been applied in a multi-step process for the production of plastic moulds to be used in the fabrication of separation nozzles by electrodeposition. For characteristic dimensions of a few microns a total height of the nozzle structure of about 400 µm has been achieved. Structural details of about 0.1 µm are being reproduced across

E. W. Backer; W. Ehrfeld; D. Münchmeyer; H. Betz; A. Heuberger; S. Pongratz; W. Glashauser; H. J. Michel; R. Siemens

1982-01-01

197

Selection of water treatment processes special study. [Uranium Mill Tailings Remedial Action (UMTRA) Project  

SciTech Connect

Characterization of the level and extent of groundwater contamination in the vicinity of Title I mill sites began during the surface remedial action stage (Phase 1) of the Uranium Mill Tailings Remedial Action (UMTRA) Project. Some of the contamination in the aquifer(s) at the abandoned sites is attributable to milling activities during the years the mills were in operation. The restoration of contaminated aquifers is to be undertaken in Phase II of the UMTRA Project. To begin implementation of Phase II, DOE requested that groundwater restoration methods and technologies be investigated by the Technical Assistance Contractor (TAC). and that the results of the TAC investigations be documented in special study reports. Many active and passive methods are available to clean up contaminated groundwater. Passive groundwater treatment includes natural flushing, geochemical barriers, and gradient manipulation by stream diversion or slurry walls. Active groundwater.cleanup techniques include gradient manipulation by well extraction or injection. in-situ biological or chemical reclamation, and extraction and treatment. Although some or all of the methods listed above may play a role in the groundwater cleanup phase of the UMTRA Project, the extraction and treatment (pump and treat) option is the only restoration alternative discussed in this report. Hence, all sections of this report relate either directly or indirectly to the technical discipline of process engineering.

Not Available

1991-11-01

198

Enhanced selectivity in CZE multi-chiral selector enantioseparation systems: proposed separation mechanism.  

PubMed

It has been reported many times that the commercial mixtures of chiral selectors (CS), namely highly sulfated beta-CDs (HS-beta-CDs), provide remarkable enantioselectivity in CZE when compared with single-isomer CDs, even single-isomer HS-beta-CDs. This enhanced enantioselectivity of multi-CS enantioseparative CZE is discussed in the light of multi-CS model that we have introduced earlier. It is proposed on a theoretical basis and verified experimentally that the two enantiomers of a chiral analyte under interaction with a mixture of CSs are very likely to differ in their limit mobilities, which is opposite to single-CS systems where the two limit mobilities are likely to be the same. Thus while the enantioseparation is usually controlled by different distribution constants between the two enantiomers and CS used in single-CS systems, an additional, electrophoretic, enantioselective mechanism resulting from different limit mobilities may play a significant role in multi-CS systems. This additional mechanism generally makes the multi-CS systems more selective than the single-CS systems. The possible inequality of limit mobilities is also significant for optimization of separation conditions using mixtures of CSs. A practical example supporting our considerations is shown on enantioseparation of lorazepam in the presence of a commercial mixture of HS-beta-CDs and a single-isomer HS-beta-CD, heptakis(6-O-sulfo)-beta-CD. PMID:20358549

Dubský, Pavel; Svobodová, Jana; Tesarová, Eva; Gas, Bohuslav

2010-05-01

199

Ordered, mesoporous metal phosphonate materials with microporous crystalline walls for selective separation techniques.  

PubMed

Ordered, hexagonal, mesoporous metal (Ti, Zr, V, Al)-phosphonate materials with microporous crystalline walls are synthesized through a microwave-assisted procedure by using triblock copolymer F127 as the template. Corresponding metal chlorides and ethylene diamine tetra(methylene phosphonic acid) are chosen as the inorganic precursors and the coupling molecule, respectively. X-ray diffractometry, transmission electron microscopy, N(2) sorption, and thermogravimetry measurements confirm that the obtained metal phosphonates possess a hierarchically porous structure with pore sizes of 7.1-7.5 nm and 1.3-1.7 nm for mesopores and micropores, respectively, and the metal phosphonate materials are thermally stable up to around 450 °C with the pore structure and hybrid framework well preserved. Magic angle spinning NMR, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses indicate that the phosphonate groups are homogenously incorporated into the hybrid framework of the obtained materials. For the first time, the mesoporous hybrid materials are employed as the stationary phase in open tubular capillary electrochromatography technique for the separation of various substances including acidic, basic, and neutral compounds. These materials show good selectivity and reproducibility for this application. PMID:21574251

Ma, Tian-Yi; Li, Hui; Tang, An-Na; Yuan, Zhong-Yong

2011-07-01

200

Algorithm for nonlinear blind source separation based on feature vector selection  

Microsoft Academic Search

A linear blind source separation algorithm based on generalized eigen-equation resolving is presented. Then a nonlinear blind source separation algorithm is proposed by extending the linear source separation algorithm to the nonlinear domain. The received mixing signals are first mapped to high-dimensional kernel feature space, and a feature vector basis given by the fitness function of the kernel feature space

Zheng Mao; Zhang Wenxi; Zheng Linhua

2010-01-01

201

Selection of Genetic and Phenotypic Features Associated with Inflammatory Status of Patients on Dialysis Using Relaxed Linear Separability Method  

PubMed Central

Identification of risk factors in patients with a particular disease can be analyzed in clinical data sets by using feature selection procedures of pattern recognition and data mining methods. The applicability of the relaxed linear separability (RLS) method of feature subset selection was checked for high-dimensional and mixed type (genetic and phenotypic) clinical data of patients with end-stage renal disease. The RLS method allowed for substantial reduction of the dimensionality through omitting redundant features while maintaining the linear separability of data sets of patients with high and low levels of an inflammatory biomarker. The synergy between genetic and phenotypic features in differentiation between these two subgroups was demonstrated.

Bobrowski, Leon; Lukaszuk, Tomasz; Lindholm, Bengt; Stenvinkel, Peter; Heimburger, Olof; Axelsson, Jonas; Barany, Peter; Carrero, Juan Jesus; Qureshi, Abdul Rashid; Luttropp, Karin; Debowska, Malgorzata; Nordfors, Louise; Schalling, Martin; Waniewski, Jacek

2014-01-01

202

Selection and Characterization of Carbon Black and Surfactants for Development of Small Scale Uranium Oxicarbide Kernels  

SciTech Connect

This report supports the effort for development of small scale fabrication of UCO (a mixture of UO{sub 2} and UC{sub 2}) fuel kernels for the generation IV high temperature gas reactor program. In particular, it is focused on optimization of dispersion conditions of carbon black in the broths from which carbon-containing (UO{sub 2} {center_dot} H{sub 2}O + C) gel spheres are prepared by internal gelation. The broth results from mixing a hexamethylenetetramine (HMTA) and urea solution with an acid-deficient uranyl nitrate (ADUN) solution. Carbon black, which is previously added to one or other of the components, must stay dispersed during gelation. The report provides a detailed description of characterization efforts and results, aimed at identification and testing carbon black and surfactant combinations that would produce stable dispersions, with carbon particle sizes below 1 {micro}m, in aqueous HMTA/urea and ADUN solutions. A battery of characterization methods was used to identify the properties affecting the water dispersability of carbon blacks, such as surface area, aggregate morphology, volatile content, and, most importantly, surface chemistry. The report introduces the basic principles for each physical or chemical method of carbon black characterization, lists the results obtained, and underlines cross-correlations between methods. Particular attention is given to a newly developed method for characterization of surface chemical groups on carbons in terms of their acid-base properties (pK{sub a} spectra) based on potentiometric titration. Fourier-transform infrared (FTIR) spectroscopy was used to confirm the identity of surfactants, both ionic and non-ionic. In addition, background information on carbon black properties and the mechanism by which surfactants disperse carbon black in water is also provided. A list of main physical and chemical properties characterized, samples analyzed, and results obtained, as well as information on the desired trend or range of values generally associated with better dispersability, is provided in the Appendix. Special attention was given to characterization of several surface-modified carbon blacks produced by Cabot Corporation through proprietary diazonium salts chemistry. As demonstrated in the report, these advanced carbons offer many advantages over traditional dispersions. They disperse very easily, do not require intensive mechanical shearing or sonication, and the particle size of the dispersed carbon black aggregates is in the target range of 0.15-0.20 {micro}m. The dispersions in water and HMTA/urea solutions are stable for at least 30 days; in conditions of simulated broth, the dispersions are stable for at least 6 hours. It is proposed that the optimization of the carbon black dispersing process is possible by replacing traditional carbon blacks and surfactants with surface-modified carbon blacks having suitable chemical groups attached on their surface. It is recognized that the method advanced in this report for optimizing the carbon black dispersion process is based on a limited number of tests made in aqueous and simulated broth conditions. The findings were corroborated by a limited number of tests carried out with ADUN solutions by the Nuclear Science and Technology Division at Oak Ridge National Laboratory (ORNL). More work is necessary, however, to confirm the overall recommendation based on the findings discussed in this report: namely, that the use of surface-modified carbon blacks in the uranium-containing broth will not adversely impact the chemistry of the gelation process, and that high quality uranium oxicarbide (UCO) kernels will be produced after calcination.

Contescu, Cristian I [ORNL

2006-01-01

203

Selective loss of progenitor subsets following clinical CD34+ cell enrichment by magnetic field, magnetic beads or chromatography separation  

Microsoft Academic Search

In this preclinical evaluation we have compared the efficacy of three clinical CD34+enrichment procedures with respect to purity, yield and recovery, as well as risk of selective loss of CD34+ lineage-specific subsets. The three devices work by different principles and have several different manipulation steps: The magnetic field separator uses paramagnetic iron-dextran particles; the magnetic microbead selection is based on

HE Johnsen; M Hutchings; E Taaning; T Rasmussen; LM Knudsen; SW Hansen; H Andersen; E Gaarsdal; L Jensen; K Nikolajsen; E Kjæsgård; NE Hansen

1999-01-01

204

Novel biphasic separations utilising highly selective molecularly imprinted polymers as biorecognition solvent extraction agents.  

PubMed

Molecularly imprinted polymers (MIPs) represent a class of artificial receptors that promise an environmentally robust alternative to naturally occurring biorecognition elements of biosensing devices and systems. However, in general, the performance of conventional MIPs in aqueous environments is poor. In the study reported here, this limitation has been addressed by the novel application of MIPs as a solvent extraction solid phase in a biphasic solvent system. This paper describes a previously unreported use of MIPs as solvent extraction reagents, their successful application to aqueous sample media and the opportunities for utilisation of this unique system in novel biosensing and separation procedures. This study demonstrates the development of a novel biphasic solvent system utilising MIP in the extracting phase to enhance both efficiency and selectivity of a simple two phase liquid extraction. Monodisperse propranolol imprinted polymer microspheres [p(divinylbenzene-co-methacrylic acid)] were prepared by precipitation polymerisation. Initially, the affinity of the polymers for (R,S)-propranolol was assessed by established techniques whereby the MIP demonstrated greater affinity for the template than did the non-imprinted control polymer (NIP). Importantly, MIP performance was also assessed using the novel dual solvent system. The depletion of (R,S)-propranolol from the aqueous phase into the polymer containing organic phase was determined. When compared to control extractions containing no polymer the presence of MIP in the extracting solvent phase resulted in an increased extraction of (R,S)-propranolol from the aqueous phase. Importantly, this extraction was significantly greater in the presence of MIP when compared to NIP. This unique principle generates opportunities for MIP based extractions and chemical enrichments in industrial applications, offering commercial, ecological and practical advantages to traditional solvent extraction techniques. The technique is readily transferable to analytical microsystems utilising MIP recognition elements generating promising opportunities for MIP based sensing of aqueous sample media. PMID:16938448

Castell, Oliver K; Allender, Christopher J; Barrow, David A

2006-10-15

205

A critical overview of non-aqueous capillary electrophoresis. Part I: mobility and separation selectivity.  

PubMed

This two-part review critically gives an overview on the theoretical and practical advances in non-aqueous capillary electrophoresis (NACE) achieved over the recent five years. Part I starts out by reviewing the aspects relevant to electromigration in organic solvents and evaluates potential advantages of the latter in comparison to aqueous solvent systems. The crucial role of solubility for the species involved in CE - analytes and back ground electrolyte constituents - is discussed both for ionic and neutral compounds. The impact of organic solvents on the electrophoretic and electroosmotic mobility and on the ionization (pKa values) of weak acids and bases is highlighted. Special emphasis is placed on methanol, acetonitrile and mixtures of these solvents, being the most frequent employed media for NACE applications. In addition, also solvents less commonly used in NACE will be covered, including other alcohols, amides (formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide), propylene carbonate, dimethylsulphoxide, and nitromethane. The discussions address the consequences of dramatic pKa shifts frequently seen for weak acids and bases, and the important contributions of medium-specific electroosmotic flow (EOF) to electromigration in nonaqueous media. Important for NACE, the role of the water content on pKa and mobility is analyzed. Finally, association phenomena rather specific to nonaqueous solvents (ion pairing, homo- and heteroconjugation) will be addressed, along with their potential advantages for the development of NACE separation protocols. It is pointed out that this review is not intended as a listing of all papers that have been published on NACE in the period mentioned above. It rather deals with general aspects of migration and selectivity in organic solvent systems, and discusses - critically - examples from the literature with particular interest to the topic. An analog discussion about the role of the solvent on efficiency will be presented in Part II. PMID:24468239

Kenndler, Ernst

2014-03-28

206

Alternate site selection process for UMTRA (Uranium Mill Tailings Remedial Action) project sites  

SciTech Connect

The purpose of this document is to describe the guidelines and processes to be used by the Department of Energy (DOE) with input from the affected states and tribes to select alternate disposal sites in compliance with each established cooperative agreement. This document supersedes two previous DOE documents, Criteria for Evaluating Disposal Sites (DOE, 1982) and Alternate Site Selection Process (ASSP) for UMTRA Project Sites (DOE, 1986). This revision of the ASSP was prepared in response to the proposed groundwater protection standards that amend 40 CF 192. The principal modifications are to the ASSP screening criteria for hydrological and geological conditions at candidate disposal sites. The revised screening and selection criteria will assist the project in selecting disposal sites where the probability of compliance with the proposed groundwater standards is high. The ASSP described in Section 2.0 consists of three phases: Phases I -- designation of a search region; Phase II -- preliminary screening of the designated search region; and Phase III -- identification and evaluation of candidate sites. Section 3.0 discusses how the results of the ASSP will be reported. This process provides a technically sound and publicly defensible approach for identifying potentially suitable disposal sites. 4 refs., 1 fig., 3 tabs.

Not Available

1988-06-01

207

Size-selective separation of submicron particles in suspensions with ultrasonic atomization.  

PubMed

Aqueous suspensions containing silica or polystyrene latex were ultrasonically atomized for separating particles of a specific size. With the help of a fog involving fine liquid droplets with a narrow size distribution, submicron particles in a limited size-range were successfully separated from suspensions. Performance of the separation was characterized by analyzing the size and the concentration of collected particles with a high resolution method. Irradiation of 2.4MHz ultrasound to sample suspensions allowed the separation of particles of specific size from 90 to 320nm without regarding the type of material. Addition of a small amount of nonionic surfactant, PONPE20 to SiO2 suspensions enhanced the collection of finer particles, and achieved a remarkable increase in the number of collected particles. Degassing of the sample suspension resulted in eliminating the separation performance. Dissolved air in suspensions plays an important role in this separation. PMID:24798229

Nii, Susumu; Oka, Naoyoshi

2014-11-01

208

Laser isotope separation  

DOEpatents

A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

Robinson, C. Paul (Los Alamos, NM) [Los Alamos, NM; Jensen, Reed J. (Los Alamos, NM) [Los Alamos, NM; Cotter, Theodore P. (Munich, DE) [Munich, DE; Boyer, Keith (Los Alamos, NM) [Los Alamos, NM; Greiner, Norman R. (Los Alamos, NM) [Los Alamos, NM

1988-01-01

209

Photochemical isotope separation  

DOEpatents

A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

Robinson, C. Paul (Los Alamos, NM) [Los Alamos, NM; Jensen, Reed J. (Los Alamos, NM) [Los Alamos, NM; Cotter, Theodore P. (Los Alamos, NM) [Los Alamos, NM; Greiner, Norman R. (Los Alamos, NM) [Los Alamos, NM; Boyer, Keith (Los Alamos, NM) [Los Alamos, NM

1987-01-01

210

Photochemical isotope separation  

DOEpatents

A process is described for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium. 8 figs.

Robinson, C.P.; Jensen, R.J.; Cotter, T.P.; Greiner, N.R.; Boyer, K.

1987-04-28

211

Uranium extraction process  

SciTech Connect

Uranium is extracted from wet process phosphoric acid by extraction with a mixture of a diorganophosphate and a neutral phosphorus compound, which is preferably a triorgano phosphine oxide, in the presence of nitrate to form an organic extract layer containing uranium and an aqueous acid layer, which are separated.

Rose, M.A.

1983-05-03

212

Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene  

SciTech Connect

Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C{sub 2}H{sub 2}/C{sub 2}H{sub 4} have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C{sub 2}H{sub 2} and C{sub 2}H{sub 4}. The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C{sub 2}H{sub 2}/C{sub 2}H{sub 4}.

Xiang, Sheng-Chang [University of Texas at San Antonio (UTSA); Zhang, Zhangjing [University of Texas at San Antonio (UTSA); Zhao, Cong-Gui [University of Texas at San Antonio (UTSA); Hong, Kunlun [ORNL; Zhao, Xuebo [University of Newcastle upon Tyne; Ding, De-Rong [University of Texas at San Antonio (UTSA); Xie, Ming-Hua [University of Texas, Pan American, Edinburg, TX; Wu, Chuan-De [University of Texas, Pan American, Edinburg, TX; Madhab, Das [University of Texas at San Antonio (UTSA); Gill, Rachel [University of Newcastle upon Tyne; Thomas, K Mark [University of Newcastle upon Tyne; Chen, Banglin [University of Texas at San Antonio (UTSA)

2011-01-01

213

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Paducah Gaseous Diffusion Plant site  

Microsoft Academic Search

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. The U-AVLIS process is based on electrostatic extraction of photoionized U-235 atoms from an atomic vapor stream created by electron-beam vaporization of uranium metal alloy. The U-235 atoms are ionized when precisely tuned laser light -- of appropriate power,

G. J. Marmer; C. P. Dunn; K. L. Moeller; J. M. Pfingston; A. J. Policastro; C. R. Yuen; J. H. Cleland

1991-01-01

214

Magnetically separable nanocomposites with photocatalytic activity under visible light for the selective transformation of biomass-derived platform molecules  

EPA Science Inventory

Novel magnetically separable TiO2-guanidine-(Ni,Co)Fe2O4 nanomaterials were prepared and characterised by a series of techniques including XRD, SEM, TEM, N2 physisorption as well as XPS and subsequently tested for their photocatalytic activities in the selective transformation of...

215

Highly Selective H(2) Separation Zeolite Membranes for Coal Gasification Membrane Reactor Applications. (Annual Technical Report, September 2003-September 2004).  

National Technical Information Service (NTIS)

It is desirable to develop inorganic zeolite membranes that are capable of highly selective H(sub 2) separation from other light gases (CO(sub 2), CH(sub 4), CO). Zeolite membranes are thermally, chemically and mechanically stable, and have tunable molecu...

M. Hong R. D. Noble J. L. Falconer

2005-01-01

216

Selective separation of sodium ions from a mixture with phenylalanine by Donnan dialysis with a profiled sulfogroup cation exchange membrane  

NASA Astrophysics Data System (ADS)

The possibility of separating ions of metal from a mixture with ampholyte (an amino acid) by Donnan dialysis with an MK-40 sulfogroup cation exchange membrane is demonstrated. Conditions ensuring the selectivity and intensity of the mass transfer of sodium ions from a mixture with bipolar phenylalanine ions into a diffusate containing hydrochloric acid through a cation exchange membrane are found.

Vasil'eva, V. I.; Goleva, E. A.

2013-11-01

217

Acetohydrazide Derivative for Selective Separation and Preconcentration of Cu(II) Ions by Coprecipitation Method Without Using a Carrier Element  

Microsoft Academic Search

A simple and rapid procedure based on the combination of carrier element free coprecipitation (CEFC) and flame atomic absorption spectrometric (FAAS) determinations has been developed for selective separation and preconcentration of Cu(II) ions in some environmental solid (Turkish and import coffee) and liquid (sea and stream waters) samples. In this method, acetohydrazide derivative was used as an organic coprecipitant without

Duygu Ozdes; Celal Duran; Hakan Bekta?; Mehmet Tufekci; Mustafa Soylak

2012-01-01

218

SELECTED ANNOTATED BIBLIOGRAPHY OF THE GEOLOGY AND OCCURRENCE OF URANIUM BEARING MARINE BLACK SHALES IN THE UNITED STATES  

Microsoft Academic Search

This bibliography consists of 81 annotated references concerned with the ; geology and occurence of uranium in marine black shales. The annotations, ; arranged alphabetically by author, present information on geology, geographic ; distribution, environment of deposition, mode of occurrence, and analytical data. ; A map shows the distribution and uranium content of uraniferous shales in the ; United States

Fix

1958-01-01

219

Evaluation of health risks associated with proposed ground water standards at selected inactive uranium mill-tailings sites  

Microsoft Academic Search

The US Environmental Protection Agency (EPA) has proposed ground water standards applicable to all inactive uranium mill-tailings sites. The proposed standards include maximum concentration limits (MCL) for currently regulated drinking water contaminants, as well as the addition of standards for molybdenum, uranium, nitrate, and radium-226 plus radium-228. The proposed standards define the point of compliance to be everywhere downgradient of

L. D. Hamilton; W. H. Medeiros; A. Meinhold; S. C. Morris; P. D. Moskowitz; J. Nagy; K. Lackey

1989-01-01

220

Electrospun polystyrene nanofiber membrane with superhydrophobicity and superoleophilicity for selective separation of water and low viscous oil.  

PubMed

The ability to prepare solid surfaces with well-controlled superhydrophobic and superoleophilic properties is of paramount importance to water-oil separation technology. Herein, we successfully prepared superhydrophobic-superoleophilic membranes by single-step deposition of polystyrene (PS) nanofibers onto a stainless steel mesh via electrospinning. The contact angles of diesel and water on the prepared PS nanofiber membrane were 0° and 155° ± 3°, respectively. Applications of the PS nanofiber membrane toward separating liquids with low surface tension, such as oil, from water were investigated in detail. Gasoline, diesel, and mineral oil were tested as representative low-viscosity oils. The PS nanofiber membranes efficiently separated several liters of oil from water in a single step, of only a few minutes' duration. The superhydrophobic PS nanofiber membrane selectively absorbs oil, and is highly efficient at oil-water separation, making it a very promising material for oil spill remediation. PMID:24090059

Lee, Min Wook; An, Seongpil; Latthe, Sanjay S; Lee, Changmin; Hong, Seungkwan; Yoon, Sam S

2013-11-13

221

Separation and Recovery of Uranium, Neptunium, and Plutonium from High Level Waste Using Tributyl Phosphate: Countercurrent Studies with Simulated Waste Solution  

Microsoft Academic Search

The present work deals with countercurrent extraction studies on the partitioning of uranium, neptunium, and plutonium using 30% tributyl phosphate (TBP) from simulated high level waste solution generated during reprocessing of spent uranium fuel from pressurized heavy water reactors. The oxidation states of neptunium and plutonium were adjusted either by 0.01 M potassium dichromate or 0.01 M dioxovanadium ion. Neptunium

R. R. Chitnis; P. K. Wattal; A. Ramanujam; P. S. Dhami; V. Gopalakrishnan; J. N. Mathur; M. S. Murali

1998-01-01

222

Evaluation of selected detector systems for products formed in the atmospheric hydrolysis of uranium hexafluoride  

SciTech Connect

Sensitive detection of UF/sub 6/ hydrolysis products, either by discontinuous sampling or by continuous or near real-time monitoring, is an important safety consideration for DOE contractors handling large quantities of UF/sub 6/. Automated continuous or rapid intermittent remote sensing of these reaction products can provide an alarm signal when a preselected threshold value has been exceeded (absolute response) or when a significant emission excursion has occurred (rate of change of response). This report evaluates the performance of selected devices for the detection of airborne materials formed in the release of liquid UF/sub 6/ (approx. =1.3 g) into an enclosed volume of 6 m/sup 3/; these experiments were initiated on October 23, 1986. The detection principles investigated are: photometric, gas detector tubes, and electrochemical sensor.

Bostick, W.D.; Bostick, D.T.

1987-03-01

223

ANALYSIS OF URANIUM, THORIUM AND ZIRCONIUM  

Microsoft Academic Search

Considering the physico-chemical conditions for tributyl phosphate ; uranium extraction, the optimum nitrate concentration of the aqueous phase in ; which uranium separation by single extraction amounted virtually to 100% was ; determined. The extraction was carried out in tributyl phosphate--petrol ; solution and the uranium re-extracted in a dilute ammonium carbonate solution. ; The uranium content was determined by

Gy. Almassy; M. Ordogh; A. Schneer

1959-01-01

224

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms  

SciTech Connect

With increased application of MOX fuels and longer burnup times for conventional fuels, higher concentrations of the transplutonium actinides Am and Cm (and even heavier species like Bk and Cf) will be produced. The half-lives of the Am isotopes are significantly longer than those of the most important long-lived, high specific activity lanthanides or the most common Cm, Bk and Cf isotopes, thus the greatest concern as regards long-term radiotoxicity. With the removal and transmutation of Am isotopes, radiation levels of high level wastes are reduced to near uranium mineral levels within less than 1000 years as opposed to the time-fram if they remain in the wastes.

Kenneth L. Nash; Sue B. Clark; Gregg Lumetta

2009-09-23

225

Remedial action plan and site design for stabilization of the inactive uranium processing site at Naturita, Colorado. Remedial action selection report, Attachment 2, Geology report: Preliminary final  

SciTech Connect

The uranium processing site near Naturita, Colorado, is one of 24 inactive uranium mill sites designated to be cleaned up by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), Public Law 95-604. Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE`s remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which serves two purposes. First, it describes the activities that are proposed by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium processing site near Naturita, Colorado. Second, this document and the rest of the RAP, upon concurrence and execution by the DOE, the state of Colorado, and the NRC, become Appendix B of the cooperative agreement between the DOE and the State of Colorado.

Not Available

1993-08-01

226

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Remedial action selection report. Revised final report  

SciTech Connect

The uranium mill tailings site near Durango, Colorado, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE`s Remedial Action Plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which has been developed to serve a two-fold purpose. First, it describes the activities that have been conducted by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium mill processing site near Durango, Colorado. Secondly, this document and the rest of the RAP, upon concurrence and execution by the DOE, the State of Colorado, and the NRC, become Appendix B of the Cooperative Agreement between the DOE and the State of Colorado.

Not Available

1991-12-01

227

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Remedial action selection report  

SciTech Connect

The uranium mill tailings site near Durango, Colorado, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's Remedial Action Plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which has been developed to serve a two-fold purpose. First, it describes the activities that have been conducted by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium mill processing site near Durango, Colorado. Secondly, this document and the rest of the RAP, upon concurrence and execution by the DOE, the State of Colorado, and the NRC, become Appendix B of the Cooperative Agreement between the DOE and the State of Colorado.

Not Available

1991-12-01

228

Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.  

PubMed

A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples. PMID:24231318

Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

2013-12-15

229

pH dependent separation of uranium by chelation chromatography using pyridine 2,6-dimethanol as a chelator: single crystal X-ray structural confirmation of the chelated uranium complex.  

PubMed

A very effective sorbent material which exhibits exceptional capture of hexavalent uranium from other actinides and lanthanides at microg g(-1) level, features pyridine 2,6-dimethanol immobilized onto alumina. The maximum sorption capacity for dioxouranium(VI) was found as 1.96 mmol g(-1) at pH 3.0. The adsorbed uranium complex was eluted completely by 0.05 mol L(-1) (NH(4))(2)CO(3) solution and the concentration of hexavalent dioxouranium ion was monitored spectrophotometrically using Arsenazo III. The structure of the chelated uranium complex has been confirmed by single crystal X-ray structure analysis and Fourier transform infrared red (FTIR) spectroscopy. Thermo gravimetric analysis/differential thermo gravimetric analysis (TGA/DTG) of the chelated uranium complex was performed. The method is reproducible with a relative standard deviation (RSD) of 1.2% (N=10) and the three sigma detection limits (N=15) 1.2 microg mL(-1) respectively. A pre-concentration factor, almost 500, for uranium was achieved. Interferences from Th(4+), Mn(2+), Ni(2+) and Cu(2+) ions were masked with ethylene diamine tetra acetic acid (di-sodium salt) (Na(2)EDTA) in the aqueous phase. The developed method has been tested for uranium recovery and estimation in some certified reference materials and environmental samples. PMID:20510512

Saha, Raja; Das, Sudipta; Banerjee, Arnab; Sahana, Animesh; Sudarsan, M; Slawin, A M Z; Li, Yang; Das, Debasis

2010-09-15

230

Hydrogen Selective Inorganic membranes for Gas Separations under High Pressure Intermediate Temperature Hydrocarbonic Envrionment  

SciTech Connect

In this project, we have successfully developed a full scale commercially ready carbon molecular sieve (CMS) based membrane for applications in H{sub 2} recovery from refinery waste and other aggressive gas streams. Field tests at a refinery pilot plant and a coal gasification facility have successfully demonstrated its ability to recovery hydrogen from hydrotreating and raw syngas respectively. High purity H{sub 2} and excellent stability of the membrane permeance and selectivity were obtained in testing conducted over >500 hours at each site. The results from these field tests as well as laboratory testing conclude that the membranes can be operated at high pressures (up to 1,000 psig) and temperatures (up to 300 C) in presence of aggressive contaminants, such as sulfur and nitrogen containing species (H{sub 2}S, CO{sub 2}, NH{sub 3}, etc), condensable hydrocarbons, tar-like species, heavy metals, etc. with no observable effect on membrane performance. By comparison, similar operating conditions and/or environments would rapidly destroy competing membranes, such as polymeric, palladium, zeolitic, etc. Significant cost savings can be achieved through recovering H{sub 2} from refinery waste gas using this newly developed CMS membrane. Annual savings of $2 to 4MM/year (per 20,000 scfd of waste gas) can be realized by recovering the H{sub 2} for reuse (versus fuel). Projecting these values over the entire US market, potential H{sub 2} savings from refinery waste gases on the order of 750 to 1,000MM scfd and $750 to $1,000MM per year are possible. In addition to the cost savings, potential energy savings are projected to be ca. 150 to 220 tBTU/yr and CO{sub 2} gas emission reductions are projected to be ca. 5,000 to 6,500MMtons/year. The full scale membrane bundle developed as part of this project, i.e., 85 x 30 inch ceramic membrane tubes packaged into a full ceramic potting, is an important accomplishment. No comparable commercial scale product exists in the inorganic membrane field. Further, this newly developed full scale bundle concept can be extended to other thin film inorganic membrane technology (Pd, zeolite, etc), providing a potential commercialization pathway for these membrane materials that demonstrate high potential in a variety of separation applications yet remain a laboratory 'novelty' for lack of a full scale support. Overall, the project has been highly successful and all of the project objectives have been met. We have developed the first of its kind commercial scale carbon molecular sieve membrane and demonstrated its performance in field testing under aggressive operating conditions and in the presence of chemical contaminants that would rapidly destroy alternative organic and inorganic membranes. This innovative membrane permits H{sub 2} recovery from gas streams that up until now have not been successfully treated with membrane or conventional technology. Our end user participant is currently pursuing the field demonstration of this membrane for hydrogen recovery at its refinery site.

Rich Ciora; Paul KT Liu

2012-06-27

231

Integrated geological, geochemical, and geophysical investigation of uranium metallogenesis in selected granitic plutons of the Miramichi Anticlinorium, New Brunswick.  

National Technical Information Service (NTIS)

Integrated geological, geochemical, and geophysical data for the post-tectonic granitic rocks of the North Pole, Burnthill, Dungarvon, Trout Brook, and Rocky Brook plutons and surrounding areas were examined to assess their potential for uranium mineraliz...

H. H. Hassan A. L. McAllister

1992-01-01

232

Evaluation of health risks associated with proposed ground water standards at selected inactive uranium mill-tailings sites.  

National Technical Information Service (NTIS)

The US Environmental Protection Agency (EPA) has proposed ground water standards applicable to all inactive uranium mill-tailings sites. The proposed standards include maximum concentration limits (MCL) for currently regulated drinking water contaminants,...

L. D. Hamilton W. H. Medeiros A. Meinhold S. C. Morris P. D. Moskowitz

1989-01-01

233

A novel method of cell separation based on dual parameter immunomagnetic cell selection  

Microsoft Academic Search

We describe a novel method of cell purification involving two stage immunomagnetic selection which permits isolation of cells based on a second cell surface marker without the need for removal of beads used in the first selection step. This approach takes advantage of the size differences between commercially available immunomagnetic beads and\\/or particles and their differing properties in terms of

Katharine M Partington; Eric J Jenkinson; Graham Anderson

1999-01-01

234

Transfer and the Part-Time Student: The Gulf Separating Community Colleges and Selective Universities  

ERIC Educational Resources Information Center

When representatives from community colleges and selective four-year institutions gather, there is no greater flashpoint than the topic of part-time enrollment. This issue--that students coming from an institution comprising mostly part-time students should be enabled to transfer to selective four-year institutions in which full-time enrollment is…

Handel, Stephen J.

2009-01-01

235

In-line assay monitor for uranium hexafluoride  

DOEpatents

An in-line assay monitor for determining the content of uranium-235 in a uranium hexafluoride gas isotopic separation system is provided which removes the necessity of complete access to the operating parameters of the system for determining the uranium-235 content. The monitor is intended for uses such as safeguard applications to assure that weapons grade uranium is not being produced in an enrichment cascade. The method and monitor for carrying out the method involve cooling of a radiation pervious chamber connected in fluid communication with the selected point in the system to withdraw a specimen and solidify the specimen in the chamber. The specimen is irradiated by means of an ionizing radiation source of energy different from that of the 185 keV gamma emissions from the uranium-235 present in the specimen. Simultaneously, the gamma emissions from the uranium-235 of the specimen and the source emissions transmitted through the sample are counted and stored in a multiple channel analyzer. The uranium-235 content of the specimen is determined from the comparison of the accumulated 185 keV energy counts and the reference energy counts. The latter is used to measure the total uranium isotopic content of the specimen. The process eliminates the necessity of knowing the system operating conditions and yet obtains the necessary data without need for large scintillation crystals and sophisticated mechanical designs.

Wallace, Steven A. (Knoxville, TN)

1981-01-01

236

Improved processing of selective NMR spectra of biopolymers by separation of noise and signal subspaces through singular-value decomposition.  

PubMed

A novel sensitivity-enhancement procedure is introduced for 2D NMR data matrices. It is based on the separation of the signal-and-noise subspaces by means of singular-value decomposition of the experimental 2D array. Although no theoretical limitation exists for a general application of the method, the reliability of the results increases considerably with reduced data sets such as those of selective measurements. Advantageous applications can be envisaged for the quantitation of NMR parameters in biopolymers whose linewidths are often large enough to undermine severely the sensitivity of selective experiments. PMID:8948139

Fedrigo, M; Fogolari, F; Viglino, P; Esposito, G

1996-11-01

237

A microporous metal-organic framework for highly selective separation of acetylene, ethylene, and ethane from methane at room temperature.  

PubMed

A novel three-dimensional microporous metal-organic framework Zn(4)L(DMA)(4) (UTSA-33, H(8) L=1,2,4,5-tetra(5-isophthalic acid)benzene, DMA=N,N'-dimethylacetamide) with small pores of about 4.8 to 6.5 Å was synthesized and structurally characterized as a non-interpenetrated (4,8)-connected network with the flu topology (Schläfli symbol: (4(12)6(12)8(4))(4(6))(2)). The activated UTSA-33a exhibits highly selective separation of acetylene, ethylene, and ethane from methane with the adsorption selectivities of 12 to 20 at 296 K, which has been established exclusively by the sorption isotherms and simulated breakthrough experiments, thus methane can be readily separated from their binary and even ternary mixtures at room temperature. PMID:22162259

He, Yabing; Zhang, Zhangjing; Xiang, Shengchang; Fronczek, Frank R; Krishna, Rajamani; Chen, Banglin

2012-01-01

238

Selection of genetic and phenotypic features associated with inflammatory status of patients on dialysis using relaxed linear separability method.  

PubMed

Identification of risk factors in patients with a particular disease can be analyzed in clinical data sets by using feature selection procedures of pattern recognition and data mining methods. The applicability of the relaxed linear separability (RLS) method of feature subset selection was checked for high-dimensional and mixed type (genetic and phenotypic) clinical data of patients with end-stage renal disease. The RLS method allowed for substantial reduction of the dimensionality through omitting redundant features while maintaining the linear separability of data sets of patients with high and low levels of an inflammatory biomarker. The synergy between genetic and phenotypic features in differentiation between these two subgroups was demonstrated. PMID:24489753

Bobrowski, Leon; ?ukaszuk, Tomasz; Lindholm, Bengt; Stenvinkel, Peter; Heimburger, Olof; Axelsson, Jonas; Bárány, Peter; Carrero, Juan Jesus; Qureshi, Abdul Rashid; Luttropp, Karin; Debowska, Malgorzata; Nordfors, Louise; Schalling, Martin; Waniewski, Jacek

2014-01-01

239

Separation of radionuclides from spent decontamination solutions onto selective inorganic-organic composite absorbers  

NASA Astrophysics Data System (ADS)

The experiments were performed to verify the possibility of the direct separation of radionuclides from a liquid decontamination waste. The solution tested were an acidic decontamination solution from the modified AP-Citrox process and a model solution simulating liquid waste from electrochemical decontamination. The efficiency of a set of inorganic absorbers was tested in both batch and dynamic column sorption tests. For the comparison, a strongly acidic cation exchanger (OSTION KS 806) was also tested. From the results obtained it was concluded that neither, composite inorganic absorbers nor strongly acidic cation exchanger can be used for the direct separation of radionuclides from either of both the solutions tested.

Rosíková, K.; Šebesta, F.; John, J.; Buchtová, K.; Motl, A.

2003-01-01

240

Line selection and parameter optimization for trace analysis of uranium in glass matrices by laser-induced breakdown spectroscopy (LIBS).  

PubMed

Laser-induced breakdown spectroscopy (LIBS) has been evaluated for the determination of uranium in real-world samples such as uraninite. NIST Standard Reference Materials were used to evaluate the spectral interferences on detection of uranium. The study addresses the detection limit of LIBS for several uranium lines and their relationship to non-uranium lines, with emphasis on spectral interferences. The data are discussed in the context of optimizing the choice of emission lines for both qualitative and quantitative analyses from a complex spectrum of uranium in the presence of other elements. Temporally resolved spectral emission intensities, line width, and line shifts were characterized to demonstrate the parameter influence on these measurements. The measured uranium line width demonstrates that LIBS acquired with moderately high spectral resolution (e.g., by a 1.25 m spectrometer with a 2400 grooves/mm grating) can be utilized for isotope shift measurements in air at atmospheric pressure with single to tens of parts per million (ppm) level detection limits, as long as an appropriate transition is chosen for analysis. PMID:24160879

Choi, Inhee; Chan, George C-Y; Mao, Xianglei; Perry, Dale L; Russo, Richard E

2013-11-01

241

Regeneration of hydrofluoric acid and selective separation of Si(IV) in a process for producing ultra-clean coal  

Microsoft Academic Search

A technique for selectively separating approximately 65 wt.% of the Si(IV) in coal has been developed. The technique first uses aqueous hydrofluoric acid (HF) to react with aluminosilicates and quartz to form fluoride complexed Al and Si species in solution. Aluminium cations, in the form of Al(NO3)3, are then added to the solution to complex fluoride as AlF2+ and hydrolyse

Karen M. Steel; John W. Patrick

2004-01-01

242

Use of ligand-modified micellar-enhanced ultrafiltration to selectively separate copper ions from wastewater streams  

SciTech Connect

The selective removal of target ions from an aqueous solution containing ions of like charge by ligand-modified micellar-enhanced ultrafiltration (LM-MEUF), is presented. In LM-MEUF, surfactant and specially tailored ligand are added to the contaminated stream. The surfactant forms aggregates called micelles, the hydrocarbon core of which the ligand complexed with the target species will solubilize. The surfactant is chosen to have the same charge type as the target ion; therefore, other ions (with similar charge) will not associate with the micelle, which makes the separation of the target ion selective. The solution is then processed by ultrafiltration, using a membrane with pore size small enough to block the passage of the micelles. In this study the divalent copper is the target ion in the solution containing divalent calcium. The surfactant is cetylpyridinium chloride (CPC) and the ligand is 4-hexadecyloxybenzyliminodiacetic acid (C{sub 16}BIDA). Experiments were conducted with batch stirred cells and the results have been compared to separation that take place under a variety of conditions in the LM-MEUF process. Rejections of copper of up to 99.8% are observed, with almost no rejection of calcium, showing that LM-MEUF has excellent selectivity and separation efficiency.

Shadizadeh, S.B.

1992-12-31

243

Selection of distinct populations of dentate granule cells in response to inputs as a mechanism for pattern separation in mice  

PubMed Central

The hippocampus is critical for episodic memory and computational studies have predicted specific functions for each hippocampal subregion. Particularly, the dentate gyrus (DG) is hypothesized to perform pattern separation by forming distinct representations of similar inputs. How pattern separation is achieved by the DG remains largely unclear. By examining neuronal activities at a population level, we revealed that, unlike CA1 neuron populations, dentate granule cell (DGC) ensembles activated by learning were not preferentially reactivated by memory recall. Moreover, when mice encountered an environment to which they had not been previously exposed, a novel DGC population—rather than the previously activated DGC ensembles that responded to past events—was selected to represent the new environmental inputs. This selection of a novel responsive DGC population could be triggered by small changes in environmental inputs. Therefore, selecting distinct DGC populations to represent similar but not identical inputs is a mechanism for pattern separation. DOI: http://dx.doi.org/10.7554/eLife.00312.001

Deng, Wei; Mayford, Mark; Gage, Fred H

2013-01-01

244

Facile fabrication of hydrophilic nanofibrous membranes with an immobilized metal-chelate affinity complex for selective protein separation.  

PubMed

In this study, we report a facile approach to fabricate functionalized poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membranes as immobilized metal affinity membranes for selective protein separation. Hydrophilic PVA-co-PE nanofibrous membranes with controlled fiber sizes were prepared via a melt extrusion process. A chelating group, iminodiacetic acid (IDA), was covalently attached to cyanuric acid activated membrane surfaces to form coordinative complexes with metal ions. The prepared membranes were applied to recover a model protein, lysozyme, under various conditions, and a high lysozyme adsorption capacity of 199 mg/g membrane was found under the defined optimum conditions. Smaller fiber size with a higher immobilized metal ion density on membrane surfaces showed greater lysozyme adsorption capacity. The lysozyme adsorption capacity remained consistent during five repeated cycles of adsorption-elution operations, and up to 95% of adsorbed lysozyme was efficiently eluted by using a phosphate buffer containing 0.5 M NaCl and 0.5 M imidazole as an elution media. The successful separation of lysozyme with high purity from fresh chicken egg white was achieved by using the present affinity membrane. These remarkable features, such as high capacity and selectivity, easy regeneration, as well as reliable reusability, demonstrated the great potential of the metal-chelate affinity complex immobilized nanofibrous membranes for selective protein separation. PMID:24377297

Zhu, Jing; Sun, Gang

2014-01-22

245

Challenging conventional f-element separation chemistry - reversing uranyl(vi)/lanthanide(iii) solvent extraction selectivity.  

PubMed

The water soluble tetradentate Schiff base, N,N'-bis(5-sulfonatosalicylidene)-diaminoethane (H2salen-SO3), will readily coordinate to the uranyl(vi) cation, but not to the same extent to trivalent lanthanide cations. This allows for the reversal of conventional solvent extraction properties and opens the possibility for novel separation processes. PMID:24958394

Hawkins, C A; Bustillos, C G; Copping, R; Scott, B L; May, I; Nilsson, M

2014-08-14

246

Separation of Selected Stable Isotopes by Liquid-Phase Thermal Diffusion and by Chemical Exchange.  

National Technical Information Service (NTIS)

Useful applications of enriched stable nuclides are unduly restricted by high cost and limited availability. Recent research on liquid phase thermal diffusion (LTD) has resulted in practical processes for separating exp 34 S, exp 35 Cl, and exp 37 Cl in s...

W. M. Rutherford B. E. Jepson E. D. Michaels

1982-01-01

247

Selective separation and purification of highly polar basic compounds using a silica-based strong cation exchange stationary phase.  

PubMed

Compared to moderately and weakly hydrophilic bases, highly polar basic compounds are even more difficult to separate due to their poor retention in reversed phase (RP) mode. This study described the successful applications of a strong cation exchange (SCX) stationary phase to achieve symmetric peak shape, adequate retention and selectivity in the separation of very polar basic compounds. Salt and acetonitrile concentrations were adjusted to optimize the separation. Good correlations (R(2)=0.998-1.000) between the logarithm of the retention factor and the logarithm of salt or acetonitrile concentration were obtained. Gradients generated by changing salt or acetonitrile concentration were compared for the analysis of different highly polar bases. Although all of the analytes were eluted more quickly with an acetonitrile gradient, the effect of the gradients tested on peak width and peak shape varied with respect to analyte. In addition, the effects of different types of cation and anion additives were also investigated. After separation parameters were acquired, the SCX-based method was utilized to analyze highly hydrophilic alkaloids from Scopolia tangutica Maxim with high separation efficiency (plate numbers>32,000 m(-1)). Concurrently, one very polar alkaloid fraction was purified with symmetric peak shape using the current method. Our results suggest that SCX stationary phase can be used as an alternative to RP stationary phase in the analysis and purification of highly hydrophilic basic compounds. PMID:24267097

Long, Zhen; Guo, Zhimou; Xue, Xingya; Zhang, Xiuli; Nordahl, Lilly; Liang, Xinmiao

2013-12-01

248

Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography.  

PubMed

The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature. PMID:22614168

Shibukawa, Masami; Taguchi, Akihiko; Suzuki, Yusuke; Saitoh, Kazunori; Hiaki, Toshihiko; Yarita, Takashi

2012-07-01

249

Membrane-based hybrid processes for high water recovery and selective inorganic pollutant separation  

Microsoft Academic Search

The removal of heavy metals (e.g. Pb(II), Cd(II), Cu(II), etc.) and oxyanions (e.g. nitrate, As(III, V), Cr(VI), etc.) is of immense interest for treatment of groundwater and other dilute aqueous systems. However, the presence of non-toxic components, such as hardness (Ca, Mg) and sulfate, can interfere with the separation of toxic species. For example, pressure-driven membrane processes, such as reverse

S. M. C Ritchie; D Bhattacharyya

2002-01-01

250

Effect of acyl chain length on selective biocatalytic deacylation on O-aryl glycosides and separation of anomers.  

PubMed

It has been demonstrated that Lipozyme® TL IM (Thermomyces lanuginosus lipase immobilised on silica) can selectively deacylate the ester function involving the C-5' hydroxyl group of ?-anomers over the other acyl functions of anomeric mixture of peracylated O-aryl ?,?-D-ribofuranoside. The analysis of results of biocatalytic deacylation reaction revealed that the reaction time decreases with the increase in the acyl chain length from C1 to C4. The unique selectivity of Lipozyme® TL IM has been harnessed for the separation of anomeric mixture of peracylated O-aryl ?,?-D-ribofuranosides, The lipase mediated selective deacylation methodology has been used for the synthesis of O-aryl ?-D-ribofuranosides and O-aryl ?-D-ribofuranosides in pure forms, which can be used as chromogenic substrate for the detection of pathogenic microbial parasites containing glycosidases. PMID:24632507

Aggarwal, Neha; Arya, Anu; Mathur, Divya; Singh, Sukhdev; Tyagi, Abhilash; Kumar, Rajesh; Rana, Neha; Singh, Rajendra; Prasad, Ashok K

2014-04-01

251

Flotation of molybdate oxyanions in dilute solutions. Part 1. Selective separation from arsenate  

Microsoft Academic Search

Ion flotation using a common cationic surfactant (dodecylamine) as collector was used for the quantitative recovery of molybdenum from dilute aqueous solutions. When arsenic co-existed with molybdenum in the solution, both arsenic and molybdenum were recovered. In this case, adsorbing colloid flotation, using ferric hydroxide as co-precipitant (or sorbent) and also dodecylamine as collector, has been examined for the selective

Zhao You-Cai; A. I. Zouboulis; K. A. Matis

1996-01-01

252

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms  

SciTech Connect

Implementation of a closed loop nuclear fuel cycle requires the utilization of Pu-containing MOX fuels with the important side effect of increased production of the transplutonium actinides, most importantly isotopes of Am and Cm. Because the presence of these isotopes significantly impacts the long-term radiotoxicity of high level waste, it is important that effective methods for their isolation and/or transmutation be developed. Furthermore, since transmutation is most efficiently done in the absence of lanthanide fission products (high yield species with large thermal neutron absorption cross sections) it is important to have efficient procedures for the mutual separation of Am and Cm from the lanthanides. The chemistries of these elements are nearly identical, differing only in the slightly stronger strength of interaction of trivalent actinides with ligand donor atoms softer than O (N, Cl-, S). Research being conducted around the world has led to the development of new reagents and processes with considerable potential for this task. However, pilot scale testing of these reagents and processes has demonstrated the susceptibility of the new classes of reagents to radiolytic and hydrolytic degradation. In this project, separations of trivalent actinides from fission product lanthanides have been investigated in studies of 1) the extraction and chemical stability properties of a class of soft-donor extractants that are adapted from water-soluble analogs, 2) the application of water soluble soft-donor complexing agents in tandem with conventional extractant molecules emphasizing fundamental studies of the TALSPEAK Process. This research was conducted principally in radiochemistry laboratories at Washington State University. Collaborators at the Radiological Processing Laboratory (RPL) at the Pacific Northwest National Laboratory (PNNL) have contributed their unique facilities and capabilities, and have supported student internships at PNNL to broaden their academic experience. New information has been developed to qualify the extraction potential of a class of pyridine-functionalized tetraaza complexants indicating potential single contact Am-Nd separation factors of about 40. The methodology developed for characterization will find further application in our continuing efforts to synthesize and characterize new reagents for this separation. Significant new insights into the performance envelope and supporting information on the TALSPEAK process has also been developed.

Kenneth L. Nash

2009-09-22

253

Usefulness of pi...pi aromatic interactions in the selective separation and analysis of imidazolium and pyridinium ionic liquid cations.  

PubMed

Current research indicates that replacing organic solvents with room-temperature ionic liquids may lead to remarkable improvements in well-known processes. Ionic liquids have already been utilized as alternative solvents in organic synthesis and catalysis, and also in electrochemistry and in separation sciences. Their wide applicability will soon result in their production on an industrial scale. Therefore, analytical methods applicable to various matrices for product control and environmental monitoring will be very much in demand. In this study, the usefulness of pi...pi interactions between alkylimidazolium and pyridinium cations and the aromatic pi...pi active moiety of the stationary phase was investigated for the selective separation and analysis of some ionic liquids. With phenyl-bonded phases, very good separations of the cations were achieved. Special attention was paid to the short-chain hydrophilic entities, known to be poorly separated on conventional reversed-phase columns. Further, the nature of the interactions occurring in the system under study was investigated by varying the content of methanol/acetonitrile used as organic modifiers in the mobile phases. The analytical method developed here is simple and reproducible, and its quantitative analytical performance was excellent. The paper also discusses the applicability of the method for monitoring degraded cations of 1-butyl-3-methylimidazolium salts obtained in the Fenton process. PMID:16847625

Stepnowski, P; Nichthauser, J; Mrozik, W; Buszewski, B

2006-08-01

254

Positive selection of NK1.1 + cells on a magnetic cell separator (MACS)  

Microsoft Academic Search

Natural killer (NK) cells are involved not only in resistance to tumors and infection, but also in some transplantation reactions. A specific, inexpensive method for purifying large numbers of NK cells is often required. All NK cells in H-2b mice express the surface marker NK1.1. We report a method for positively selecting NK1.1+ spleen cells from normal and Poly I:C-stimulated

Cynthia A. Ellison; John G. Gartner

1995-01-01

255

Separation of Boron from Geothermal Water Using a Boron Selective Macroporous Weak Base Anion Exchange Resin  

Microsoft Academic Search

In this study, batch and column mode tests were performed to evaluate the efficiency of boron removal from geothermal water containing 10-11 mg B\\/L using Lewatit MK 51 which is a macroporous weak base anion exchange resin with polyhydroxyl groups showing a very high selectivity and capacity for boron. The optimum resin amount for boron removal from geothermal water was determined as

Idil Yilmaz-Ipek; Pelin Koseoglu; Umran Yuksel; Nazl? Yasar; Gözde Yolseven; Mithat Yuksel; Nalan Kabay

2010-01-01

256

WATER AND WASTEWATER POLISHING USING 3M SELECTIVE SEPARATION REMEDIATION CARTRIDGE TECHNOLOGY  

Microsoft Academic Search

3M has developed technology for selectively removing trace levels of dissolved contaminant materials from liquids using systems operating at flow rates up to 50 gallons per minute. This technology combines active particle chemistries with a particle-loaded membrane to achieve a new medium for liquid waste processing--a spiral wound filter cartridge. This technology has shown success by generating high decontamination factors

K. M. Hoffmann; T. J. Scanlan; D. C. Seely

2002-01-01

257

Experimental verification of a predicted, hitherto unseen separation selectivity pattern in the nonaqueous capillary electrophoretic separation of weak base enantiomers by octakis (2,3-diacetyl-6-sulfato)-gamma-cyclodextrin.  

PubMed

The capillary electrophoretic separation of cationic enantiomers with single-isomer multivalent anionic resolving agents was reexamined with the help of the charged resolving agent migration model. Three general model parameters were identified that influence the shape of the separation selectivity and enantiomer mobility difference curves: parameter b, the binding selectivity (K(RCD)/K(SCD)), parameter s, the size selectivity (mu0(RCD)/mu0(SCD)), and parameter a, the complexation-induced alteration of the analyte's mobility (mu0(RCD)/mu0). In addition to the previously observed discontinuity in separation selectivity that occurs as mu(eff) of the less mobile enantiomer changes from cationic to anionic, a new feature, a separation selectivity maximum was predicted to occur in the resolving agent concentration range where both enantiomers migrate cationically provided that (i) K(RCD)/K(SCD) <1 and mu0(RCD)/mu0(SCD) >1 and (K(RCD)mu0(RCD))/(K(SCD)mu0(SCD)) > 1, or (ii) K(RCD)/K(SCD) >1 and mu0(RCD)/mu0(SCD) <1 and (K(RCD)mu0(RCD))/(K(SCD)mu0(SCD)) <1. This hitherto unseen separation selectivity pattern was experimentally verified during the nonaqueous capillary electrophoretic separation of the enantiomers of four weak base analytes in acidic methanol background electrolytes with octakis(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin (ODAS-gammaCD) as resolving agent. PMID:10879961

Zhu, W; Vigh, G

2000-06-01

258

Toxaphene chemistry: separation and characterisation of selected enantiomers of the Polychloropinene mixtures.  

PubMed

The primary goal for the study presented here was the preparation and characterisation of enantiomeric pure chlorobornane standards (Toxaphene). In this context, we partially modeled the procedure for Polychloropinene production in the former USSR. The initial reaction was ionic addition of hydrogen chloride to (1S)-alpha-pinene resulting predominantly in (1S)-2-endo-chlorobornane. Further photochlorination gave mixtures of chlorinated terpenes with different average content of Cl per molecule. The resulting mixtures were separated on a silica-gel column and a number of known hepta to decachlorobornanes were identified in fractions with the help of NMR and GC (using electron capture and mass spectrometric detection)--but in very unusual ratios as compared to the technical Toxaphene mixture formerly produced by Hercules (USA). Also several previously unknown congeners were isolated or detected. Three of the isolated congeners were obtained in crystalline state and X-ray crystallography showed their enantiomeric purity. PMID:17217982

Trukhin, Alexey; Kruchkov, Fedor; Hansen, Lars Kr; Kallenborn, Roland; Kiprianova, Anastasia; Nikiforov, Vladimir

2007-04-01

259

Selected values of chemical thermodynamic properties: compounds of uranium, protactinium, thorium, actinium, and the alkali metals. Final report  

SciTech Connect

This publication contains tables of recommended values for the standard enthalpies (heats) of formation, Gibbs (free) energies of formation, entropies, enthalpy contents and heat capacities at 298.15 K, and enthalpies of formation at O K for compounds of uranium, protactinium, thorium, actinium, lithium, sodium, potassium, rubidium, cesium, and francium.

Wagman, D.D.; Evans, W.H.; Parker, V.B.; Schumm, R.H.; Nuttall, R.L.

1981-05-01

260

Radiostrontium separation and measurement in a single step using plastic scintillators plus selective extractants. Application to aqueous sample analysis.  

PubMed

This study describes a new protocol for (90)Sr determination in water samples based on the use of a selective extractant (DtBuCH18C6) and plastic scintillator microspheres. The proposed procedure unifies chemical separation and sample measurement preparation in a single step to reduce the effort, time and reagents required for analysis. In addition, the final measurement does not produce mixed waste. The minimum activity detectable for 10 mL of sample solution is 0.46 Bq L(-1). Relative errors for the determination of (90)Sr activity in drinking, sea and river waters are less than 4%. PMID:21237307

Bagán, H; Tarancón, A; Rauret, G; García, J F

2011-02-01

261

The selective separation of 90 Sr and 99 Tc in nuclear waste using molecular recognition technology products  

Microsoft Academic Search

This paper describes the use of IBC’s AnaLig? Sr-01 and AnaLig? Tc-02 molecular recognition technology products to effectively\\u000a and selectively separate and recover strontium and technetium from radioactive waste solutions. The use and effectiveness\\u000a of AnaLig? Sr-01 and AnaLig? Tc-02 are also compared with traditional commonly applied methods using Eichrom’s Sr Resin and\\u000a TEVA Resin. Different concentrations of Ca2+, Ba2+,

B. Remenec

2006-01-01

262

The selective separation of 90 Sr and 99 Tc in nuclear waste using molecular recognition technology products  

Microsoft Academic Search

This paper describes the use of IBC’s AnaLig Sr-01 and AnaLig Tc-02 molecular recognition technology products to effectively\\u000a and selectively separate and recover strontium and technetium from radioactive waste solutions. The use and effectiveness\\u000a of AnaLig Sr-01 and AnaLig Tc-02 are also compared with traditional commonly applied methods using Eichrom’s Sr Resin and\\u000a TEVA Resin. Different concentrations of Ca2+, Ba2+,

B. Remenec

2006-01-01

263

Note on the selective separation of chromium from ferro-chrome alloys  

Microsoft Academic Search

A sensitive and highly selective method for the extractivephotometric determination of microgram amounts of molybdenum has been developed. It is based on the extraction of molybdenum(V)-thiocyanate complex in strong acidic medium (1.5-4.5 M HC1) with N-hydroxy-N-p-chlorophenylN'-(2-methyl-4-chlorophenyl)benzamidine hydrochloride (HCPMCPBH) as a mixed-chelate into benzene. The molar absorptivity of the method is 4.5  103 1-mole-lcm -1 at 470 nm. The system

A. K. Sen; R. K. Ghatuary

1979-01-01

264

URANIUM EXTRACTION SELECTIVITIES OF DIBUTYL CARBITOL AND TRIBUTYL PHOSPHATE IN THE SYSTEM UO2(NO3)2-HNO3H2OAl(NO3)3SOLVENT  

Microsoft Academic Search

Historically, both the BUTEX (dibutyl carbitol-based) and PUREX (tributyl phosphate-based) processes have been used for uranium recovery and purification. Currently, BUTEX- and PUREX-type extraction processes are being used in series for recovery of isotopically enriched uranium at the Oak Ridge Y-12 Plant. The use of two solvents is predicated on the differing selectivities of each with regard to the contaminant

Joseph F. Birdwell

1999-01-01

265

The selective separation of 90Sr and 99Tc in nuclear waste using molecular recognition technology products  

NASA Astrophysics Data System (ADS)

This paper describes the use of IBC’s AnaLig® Sr-01 and AnaLig® Tc-02 molecular recognition technology products to effectively and selectively separate and recover strontium and technetium from radioactive waste solutions. The use and effectiveness of AnaLig® Sr-01 and AnaLig® Tc-02 are also compared with traditional commonly applied methods using Eichrom’s Sr Resin and TEVA Resin. Different concentrations of Ca2+, Ba2+, Pb2+, and K+ interfering ions on Sr2+ sorption were tested. Methods for the determination of 90Sr and 99Tc with emphasis on avoiding so called “matrix effects”, maximizing chemical recoveries, selectivity, minimizing time of analyses and reaching the lowest LLD were modified or developed.

Remenec, B.

2006-01-01

266

Electromagnetic Mass Separator for Heavy Element Radioisotope Separation.  

National Technical Information Service (NTIS)

An electromagnetic mass separator of a sector type intended for uranium isotope separation and U-234 production is described. The working chamber, magnet and vacuum system are located in a special ''canyon''. Operation controlling of the vacuum system, po...

M. K. Abdulakhatov G. A. Akopov V. S. Belykh T. D. Gogoleva A. G. Evdokimov

1980-01-01

267

COMPUTATION OF THE PERFORMANCE OF A MULTICOMPONENT SOLVENT EXTRACTION SYSTEM. THE SEPARATION OF URANIUM AND PLUTONIUM FROM FISSION PRODUCTS BY TRIBUTYL PHOSPHATE  

Microsoft Academic Search

Established methods of graphical calculation for immiscible phases are ; applied to a complex multicomponent solvent extraction system--the first ; extractor of a tributyl phosphate process for irradiated uranium. Partition ; coefficients for the main components are presented, and their use in the ; calculation of extractor performance is demonstrated. Typical results of ; calculations are illustrated, and the choice

J. T. Wood; J. A. Williams

1958-01-01

268

Separation of selected imidazole enantiomers using dual cyclodextrin system in micellar electrokinetic chromatography.  

PubMed

Cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was developed for simultaneous enantioseparation of three imidazole drugs namely tioconazole, isoconazole and fenticonazole. Three easily available and inexpensive cyclodextrins namely 2-hydroxypropyl-?-cyclodextrin (HP-?-CD), 2-hydroxypropyl-?-cyclodextrin (HP-?-CD) and heptakis(2,6-di-O-methyl)-?-cyclodextrin (DM-?-CD) were evaluated to discriminate the six stereoisomers of the drugs. However, none of the three CDs gave a complete enantioseparation of the drugs. Effective enantioseparation of tioconazole, isoconazole and fenticonazole was achieved using a combination of 35 mM HP-?-CD and 10 mM DM-?-CD as chiral selectors. The best separation using both HP-?-CD and DM-?-CD (35 mM:10 mM) as chiral selectors were accomplished in background electrolyte (BGE) containing 35 mM phosphate buffer (pH 7.0), 50 mM sodium dodecyl sulfate (SDS) and 15% (v/v) acetonitrile at 27 kV and 30 °C with all peaks resolved in less than 15 min with resolutions, Rs 1.90-27.22 and peak efficiencies, N > 180 000. The developed method was linear over the concentration range of 25-200 mg l(-1) (r(2) > 0.998) and the detection limits (S/N = 3) of the three imidazole drugs were found to be 2.7-7.7 mg l(-1). The CD-MEKC method was successfully applied to the determination of the three imidazole drugs in spiked human urine sample and commercial cream formulation of tioconazole and isoconazole with good recovery (93.6-106.2%) and good RSDs ranging from 2.30-6.8%. PMID:23716264

Wan Ibrahim, Wan Aini; Abd Wahib, Siti Munirah; Hermawan, Dadan; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

2013-06-01

269

Distributed Physical and Molecular Separations for Selective Harvest of Higher Value Wheat Straw Components Project  

SciTech Connect

Wheat straw (Triticum aestivum L.) is an abundant source of plant fiber. It is regenerated, in large quantities, every year. At present, this potentially valuable resource is greatly under-exploited. Most of the excess straw biomass (i.e., tonnage above that required for agronomic cropping system sustainability) is managed through expensive chopping/tillage operations and/or burnt in the field following harvest, resulting in air pollution and associated health problems. Potential applications for wheat straw investigated within this project include energy and composites manufacture. Other methods of straw utilization that will potentially benefit from the findings of this research project include housing and building, pulp and paper, thermal insulation, fuels, and chemicals. This project focused on components of the feedstock assembly system for supplying a higher value small grains straw residue for (1) gasification/combustion and (2) straw-thermoplastic composites. This project was an integrated effort to solve the technological, infrastructural, and economic challenges associated with using straw residue for these bioenergy and bioproducts applications. The objective of the research is to contribute to the development of a low-capital distributed harvesting and engineered storage system for upgrading wheat straw to more desirable feedstocks for combustion and for straw-plastic composites. They investigated two processes for upgrading wheat straw to a more desirable feedstock: (1) an efficient combine-based threshing system for separating the intermodal stems from the leaves, sheaths, nodes, and chaff. (2) An inexpensive biological process using white-rot fungi to improve the composition of the mechanically processed straw stems.

N /A

2004-09-30

270

Improved accuracy of U-Pb zircon dating by selection of more concordant fractions using a high gradient magnetic separation technique  

NASA Astrophysics Data System (ADS)

A loop of soft iron wire or a paper clip or a ferromagnetic grid mounted between the poles of an electromagnet picks up and allows further magnetic separation of zircons previously found to be non-magnetic on a Frantz Isodynamic Separator. Tests on previously analysed samples indicate that most such zircons that are fairly discordant (say ~10%) can be picked up and isolated from associated grains that are more concordant. Tests on new samples indicate that even when most grains can be picked up the last few percent of the sample contain less uranium, and are more concordant than the bulk sample. The degree of discordance is the dominant factor affecting the uncertainty of U-Pb zircon ages both because of the error amplification in projections, and because the assumption of a simple two-stage system may not be valid. Only by eliminating or reducing discordance can errors approaching the uncertainty in a single analysis, say ±2 m.y. for 2700 m.y. rocks, be achieved. Rutile normally concentrated with zircon as non-magnetic has been successfully removed from a small amount of low uranium zircon, using the high intensity separation technique.

Krogh, T. E.

1982-04-01

271

WATER AND WASTEWATER POLISHING USING 3M SELECTIVE SEPARATION REMEDIATION CARTRIDGE TECHNOLOGY  

SciTech Connect

3M has developed technology for selectively removing trace levels of dissolved contaminant materials from liquids using systems operating at flow rates up to 50 gallons per minute. This technology combines active particle chemistries with a particle-loaded membrane to achieve a new medium for liquid waste processing--a spiral wound filter cartridge. This technology has shown success by generating high decontamination factors and reducing contaminants to part per trillion levels. The spiral wound cartridge offers simplified installation, convenient replacement, and clean, easy disposal of a concentrated waste. By incorporating small, high surface area particles (5 to 80 microns) into a sturdy, yet porous, membrane greater removal efficiencies of even trace contaminants can be achieved at higher flow rates than with conventional column systems. In addition, the captive-particle medium prevents channeling of liquids and insures uniform flow across the sorbing particle surface. The cartridges fit into standard, commercially-available housings and whole system capital costs are substantially lower than those of column or reverse osmosis systems. Developmental work at high degrees of water polishing have included removal of mercury from contaminated wastewater, various radionuclides from process water, and organometallic species from surface water discharges. Laboratory testing and on-site demonstration data of these applications show the levels of success that have been achieved thus far.

Hoffmann, K. M.; Scanlan, T. J.; Seely, D. C.

2002-02-25

272

Photophoretic separation of single-walled carbon nanotubes: a novel approach to selective chiral sorting.  

PubMed

For over two decades single-walled carbon nanotubes (SWCNTs) have been used in a broad range of electronic and optical applications, however the selective chiral sorting of SWCNTs with guaranteed optoelectronics characteristics is imperative to the industrial realization of such applications. In this paper we provide the results of modeling an optical sorting method that utilizes the inherent opto-electronic properties of the SWCNTs, thus guaranteeing the properties of the extracted populations. Utilizing the resonant transfer of photonic momentum, we simulate chiral sorting of two chiral populations in an aqueous environment based on the frequency dependent optical absorption properties of the nanotubes. We show that photonic sorting is not only feasible, but may be up to faster than density gradient centrifugation techniques. Our simulations investigate the effects of laser power, temperature and orientation. We find that 96% purity can be achieved in less than 12 minutes by operating at 9 × 10(7) W m(-2) (20 mW in a 20 ?m chamber) at elevated temperatures. PMID:24487342

Smith, David; Woods, Christopher; Seddon, Annela; Hoerber, Heinrich

2014-03-21

273

Evaluation of health risks associated with proposed ground water standards at selected inactive uranium mill-tailings sites  

SciTech Connect

The US Environmental Protection Agency (EPA) has proposed ground water standards applicable to all inactive uranium mill-tailings sites. The proposed standards include maximum concentration limits (MCL) for currently regulated drinking water contaminants, as well as the addition of standards for molybdenum, uranium, nitrate, and radium-226 plus radium-228. The proposed standards define the point of compliance to be everywhere downgradient of the tailings pile, and require ground water remediation to drinking water standards if MCLs are exceeded. This document presents a preliminary description of the Phase 2 efforts. The potential risks and hazards at Gunnison, Colorado and Lakeview, Oregon were estimated to demonstrate the need for a risk assessment and the usefulness of a cost-benefit approach in setting supplemental standards and determining the need for and level of restoration at UMTRA sites. 8 refs., 12 tabs.

Hamilton, L.D.; Medeiros, W.H.; Meinhold, A.; Morris, S.C.; Moskowitz, P.D.; Nagy, J.; Lackey, K.

1989-04-01

274

Synthesis of surface imprinted nanospheres for selective removal of uranium from simulants of Sambhar salt lake and ground water  

Microsoft Academic Search

Imprinted polymer nanospheres for uranium were prepared by complexing uranyl ion on to quinoline-8-ol functionalized 3-aminopropyltrimethoxysilane modified silica nanoparticles followed by surface imprinting with 4-VP (4-vinyl pyridine), HEMA (2-hydroxy ethyl methacrylate) and EGDMA (ethylene glycol dimethacrylate) as the functional monomers and cross linking agent respectively with AIBN (2,2?-azo-bis-isobutyronitrile) as initiator and 2-methoxyethanol as the porogen. Non-imprinted polymer material was also

Thazhathuparambil Elias Milja; Krishnapillai Padmajakumari Prathish; Talasila Prasada Rao

2011-01-01

275

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass  

Microsoft Academic Search

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium

L. Duquène; H. Vandenhove; F. Tack; M. Van Hees; J. Wannijn

2010-01-01

276

Using a Buffer Gas Modifier to Change Separation Selectivity in Ion Mobility Spectrometry  

PubMed Central

The mobilities of a set of common ?-amino acids, four tetraalkylammonium ions, 2,4-dimethyl pyridine (2,4-lutidine), 2,6-di-tert-butyl pyridine (DTBP), and valinol were determined using electrospray ionization-ion mobility spectrometry-quadrupole mass spectrometry (ESI-IMS-QMS) while introducing 2-butanol into the buffer gas. The mobilities of the test compounds decreased by varying extents with 2-butanol concentration in the mobility spectrometer. When the concentration of 2-butanol increased from 0.0 to 6.8 mmol m?3 (2.5×102 ppmv), percentage reductions in mobilities were: 13.6% (serine), 12.2% (threonine), 10.4% (methionine), 10.3% (tyrosine), 9.8% (valinol), 9.2% (phenylalanine), 7.8% (tryptophan), 5.6% (2,4-lutidine), 2.2% (DTBP), 1.0% (tetramethylammonium ion, TMA, and tetraethylammonium ion, TEA), 0.0% (tetrapropylammonium ion, TPA), and 0.3% (tetrabutylammonium ion, TBA). These variations in mobility depended on the size and steric hindrance on the charge of the ions, and were due to formation of large ion-2-butanol clusters. This selective variation in mobilities was applied to the resolution of a mixture of compounds with similar reduced mobilities such as serine and valinol, which overlapped in N2-only buffer gas in the IMS spectrum. The relative insensitivity of tetraalkylammonium ions and DTBP to the introduction of 2-butanol into the buffer gas was explained by steric hindrance of the four alkyl substituents in tetraalkylammonium ions and the two tert-butyl groups in DTBP, which shielded the positive charge of the ion from the attachment of 2-butanol molecules. Low buffer gas temperatures (100 °C) produced the largest reductions in mobilities by increasing ion-2-butanol interactions and formation of clusters; high temperatures (250 °C) prevented the formation of clusters, and no reduction in ion mobility was obtained with the introduction of 2-butanol into the buffer gas. Low temperatures and high concentrations of 2-butanol produced a series of ion clusters with one to three 2-butanol molecules in compounds without steric hindrance. Clusters of two and three molecules of 2-butanol were also visible. Ligand-saturation on the positive ions with 2-butanol molecules occurred at high concentrations of modifier (6.8 mmol m?3 at 150°C); when saturated, no further reduction in mobility occurred when 2-butanol was introduced into the buffer gas.

Fernandez-Maestre, Roberto; Wu, Ching; Hill, Herbert H.

2010-01-01

277

Environmental Readiness Document Advanced Isotope Separation Program.  

National Technical Information Service (NTIS)

Advanced Isotope Separation (AIS) techniques hold the promise of significantly reducing the cost of enriching uranium for use in commercial nuclear power reactors. By reducing uranium enrichment costs, the tails assay of an enrichment plant can be lowered...

1981-01-01

278

Uranium in soils integrated demonstration: 1992 update.  

National Technical Information Service (NTIS)

The Uranium in Soils Integrated Demonstration (ID) was initiated in 1991. The Fernald Environmental Management Project (FEMP), previously known as the Feed Materials Production Center (FMPC), was selected as the host site for the Uranium in Soils ID. The ...

K. R. Nuhfer

1992-01-01

279

Uranium soils integrated demonstration, 1993 status.  

National Technical Information Service (NTIS)

The Fernald Environmental Management Project (FEMP), operated by the Fernald Environmental Restoration Management Corporation (FERMCO) for the DOE, was selected as the host site for the Uranium Soils Integrated Demonstration. The Uranium Soils ID was esta...

K. Nuhfer

1994-01-01

280

Physicochemical Characterization of Capstone Depleted Uranium Aerosols I: Uranium Concentration in Aerosols as a Function of Time and Particle Size  

SciTech Connect

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing depleted uranium were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time particularly within the first minute after the shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% 30 min after perforation. In the Bradley vehicle, the initial (and maximum) uranium concentration was lower than those observed in the Abrams tank and decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in the cyclone samplers, which collected aerosol continuously for 2 h post perforation. The percentages of uranium mass in the cyclone separator stages from the Abrams tank tests ranged from 38% to 72% and, in most cases, varied with particle size, typically with less uranium associated with the smaller particle sizes. Results with the Bradley vehicle ranged from 18% to 29% and were not specifically correlated with particle size.

Parkhurst, MaryAnn; Cheng, Yung-Sung; Kenoyer, Judson L.; Traub, Richard J.

2009-03-01

281

Wide Angle, Single Screen, Gridded Square-Loop Frequency Selective Surface for Diplexing Two Closely Separated Frequency Bands  

NASA Technical Reports Server (NTRS)

The design and performance of a wide angle, single screen, frequency selective surface (FSS) with gridded square-loop path elements are described for diplexing closely separated signal bands, for example, X- and Ku-band signals in an Orbiting Very Long Baseline Interferometer (OVLBI) earth station reflector antenna system, as well as other applications such as military and commercial communications via satellites. Excellent agreement is obtained between the predicted and measured results of this FSS design using the gridded square-loop patch elements sandwiched between 0.0889 cm thick tetrafluoroethylene fluorocarbon polymer (PTFE) slabs. Resonant frequency drift is reduced by 1 GHz with an incidence angle from 0 deg normal to 40 deg from normal.

Wu, Te-Kao (Inventor)

1996-01-01

282

Determination of lead by selective chelatometric titration with HEDTA after separation as its sulphate by an improved method of precipitation.  

PubMed

A selective titrimetric determination of Pb after separation by a modified method of precipitation as its sulphate is proposed. Pb(II), present as the perchlorate, is precipitated by gentle boiling in 3.6M H(2)SO(4) presaturated with PbSO(4) and free from any extraneous anions. The customary time-consuming evaporation to fumes of sulphuric acid is dispensed with. The precipitate is collected, and dissolved in excess of HEDTA, the surplus of which is back-titrated with Zn(II) at pH 5.0-5.5. Use of Catechol Violet and Xylenol Orange as a mixed indicator gives a sharper end-point. The standard deviation of the proposed method for 60 mg of lead is 0.35 mg. The method has been successfully used to determine Pb in non-ferrous alloys. PMID:18965059

Nan, Z; Yao, X Z; Gu, Y X; Yu, R Q

1990-10-01

283

Tuning the selectivity of ionic liquid stationary phases for enhanced separation of nonpolar analytes in kerosene using multidimensional gas chromatography.  

PubMed

In this study, a series of ionic liquids (ILs) are evaluated as stationary phases in comprehensive two-dimensional gas chromatography (GC × GC) for the separation of aliphatic hydrocarbons from kerosene. IL-based stationary phases were carefully designed to evaluate the role of cavity formation/dispersive interaction on the chromatographic retention of nonpolar analytes by GC × GC. The maximum allowable operating temperature (MAOT) of the IL-based columns was compared to that of commercial IL-based columns. Evaluation of the solvation characteristics of GC columns guided the selection of the best performing IL-based stationary phases for the resolution of aliphatic hydrocarbons, namely, trihexyl(tetradecyl)phosphonium tetrachloroferrate ([P66614][FeCl4]) and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate ([P66614][FAP]) ILs. The best performing [P66614][FeCl4] IL-based column exhibited a MAOT of 320 °C, higher than the commercial SUPELCOWAX 10 (MAOT of 280 °C) and commercial IL-based columns (MAOT up to 300 °C). The structurally tuned [P66614][FeCl4] IL stationary phase exhibited improved separation of aliphatic hydrocarbons by GC × GC compared to the commercial columns examined (e.g., OV-1701, SUPELCOWAX 10, SLB-IL60, SLB-IL100, and SLB-IL111). PMID:24617338

Hantao, Leandro W; Najafi, Ali; Zhang, Cheng; Augusto, Fabio; Anderson, Jared L

2014-04-15

284

Robust and selective nano cavities for protein separation: an interpenetrating polymer network modified hierarchically protein imprinted hydrogel.  

PubMed

In the present work, we report a novel method for the reinforcement of hierarchically structured molecularly imprinted polymer (MIP) for the separation of human serum albumin (HSA) and immunoglobulin G (IgG) proteins under pressure driven flow conditions. The template proteins (HSA or IgG) were first physically adsorbed at their isoelectric point on the surface of wide pore silica particles. Thereafter, the pore system was filled with a monomer solution and polymerized to form a lightly crosslinked polyacrylamide network covering the protein template. In order to enhance the rigidity of the hydrogels, different type of crosslinkers such as ethylene glycol dimethacrylate (EGDMA), 3,4-dihydroxyphenethylamine (DA) and methylene-bis-acrylamide (MBA), at least partially interpenetrated into the initially made acrylamide base hydrogel leading to formation of an interpenetrating polymer network (IPN). Then the silica matrix was removed to leave highly porous and reinforced MIP. TGA together with FT-IR and TEM analysis supported the interpenetration of the secondary crosslinkers in the initially formed polymer matrix. The compression property of the modified hydrogels as a function of degree of swelling was in the following order: DA>EGDMA>MBA-IPN-modified hydrogel. Batch binding assay verified the capability of the IPN modified MIPs to capture the target proteins. Moreover, solid phase extraction, HPLC and SDS-PAGE revealed that the EGDMA modified MIP could selectively capture and separate the proteins from human serum or fermentation broth. PMID:24786659

Nematollahzadeh, Ali; Lindemann, Patrick; Sun, Wei; Stute, Jörg; Lütkemeyer, Dirk; Sellergren, Börje

2014-06-01

285

Separation of selected transition metals by capillary chelation ion chromatography using acetyl-iminodiacetic acid modified capillary polymer monoliths.  

PubMed

Capillary housed laurylmethacrylate-co-ethylene dimethacrylate (LMA-co-EDMA) polymer monoliths were fabricated, functionalised with varying amounts of vinyl azlactone, followed by immobilisation of iminodiacetic acid (IDA), forming a range of acetyl-iminodiacetic acid (AIDA) functionalised monoliths, applied to the chelation ion chromatographic separation of selected transition and heavy metals. A number of monoliths of varying length and ligand density were prepared, resulting in increased cation retention and chromatographic resolution on those displaying the highest capacity. Ligand density and related column capacity were confirmed visually using scanning capacitively coupled contactless conductivity detection (sC(4)D) techniques. Column temperature studies to determine retention mechanism and the effect of temperature on the retention of Mn(II), Cd(II) and Cu(II) was investigated, showing an increase in retention with increased temperature for Cd(II) and Cu(II), whilst a decrease in retention was obtained for Mn(II). Isocratic capillary chelation ion chromatographic separations of Mn(II), Cd(II) and Cu(II) were obtained, with dual peak detection demonstrated using combined on-column C(4)D detection and UV-Visible detection following the post-capillary column reaction of the eluted metals with 4-(2-pyridylazo) resorcinol (PAR). PMID:22762955

Moyna, Áine; Connolly, Damian; Nesterenko, Ekaterina; Nesterenko, Pavel N; Paull, Brett

2012-08-01

286

Development of a fast and selective separation method to determine histamine in tuna fish samples using capillary zone electrophoresis.  

PubMed

This paper reports on the development of a fast and selective separation method by capillary zone electrophoresis (CZE) for the determination of histamine in tuna fish samples. The background electrolyte was composed of 60 mmol L(-1) hydroxyisobutyric acid and 10 mmol L(-1) sodium hydroxide at pH 3.3. The internal standard used was imidazole. Separations were performed in a fused uncoated silica capillary (32 cm total length, 8.5 cm effective length and 50 ?m internal diameter) with direct UV detection at 210 nm. The samples and standards were injected hydrodynamically (50 mbar, 3s) from the outlet capillary end (nearest to the detector) and the electrophoretic system was operated under normal polarity and constant voltage conditions of 30 kV (positive polarity on the injection side). The migration time of histamine in the proposed method was only 0.34 min. The method was then validated and different tuna fish samples were analyzed. Good linearity (R(2)>0.999), a limit of detection 0.14 mg L(-1), intra-day precision better than 3.5% (peak area of sample), and recovery in the range of 94-108% were obtained. The results of the histamine concentration determined in the samples by the CZE method were compared with the LC-MS/MS method. PMID:23598114

Vitali, Luciano; Valese, Andressa Camargo; Azevedo, Mônia Stremel; Gonzaga, Luciano Valdemiro; Costa, Ana Carolina Oliveira; Piovezan, Marcel; Vistuba, Jacqueline Pereira; Micke, Gustavo A

2013-03-15

287

Well-defined nanostructured surface-imprinted polymers for highly selective magnetic separation of fluoroquinolones in human urine.  

PubMed

The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core-shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8-8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems. PMID:24853973

He, Yonghuan; Huang, Yanyan; Jin, Yulong; Liu, Xiangjun; Liu, Guoquan; Zhao, Rui

2014-06-25

288

Hydrothermal alteration of organic matter in uranium ores, Elliot Lake, Canada: Implications for selected organic-rich deposits  

SciTech Connect

Organic matter in the uraniferous Matinenda Formation, Elliot Lake, is preserved in the forms of syngenetic kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium ores. The Elliot Lake kerogen is a vitrinite-like material considered to be remnants of the Precambrian cyanobacterial mats. The kerogen at Elliot Lake has reflectances (in oil) ranging from 2.63-7.31% RO{sub max}, high aromaticity, relatively low (0.41-0.60) atomic H/C ratios, and it contains cryptocrystalline graphite. Bitumen, present primarily as dispersed globules (up to 0.5 mm dia.), has reflectances from 0.72-1.32% RO{sub max}, atomic H/C ratios of 0.71-0.81, and is somewhat less aromatic than the kerogen. Overall similarity in molecular compositions indicates that liquid bitumen was derived from kerogen by processes similar to hydrous pyrolysis. The carbon isotopic composition of kerogen ({minus}15.62 to {minus}24.72%), and the now solid bitumen ({minus}25.91 to {minus}33.00%) are compatible with these processes. Despite having been subjected to several thermal episodes, ca. 2.45 Ga old kerogen of microbiological origin here survived as testimony of the antiquity of life on Earth. U-Pb isotopic data from discrete kerogen grains at Elliot Lake form a scattered array intersecting concordia at 2130 {+-} 100 Ma, correspond to the Nipissing event. U-Pb systems were totally reset by this event. Uranium and lead show subsequently partial mobility, the average of which is indicated by the lower concordia intersect of 550 {+-} 260 Ma. The migrated bitumen contains virtually no uranium and thorium but has a large excess of {sup 206}Pb, which indicates that the once liquid bitumen must have acted as a sink for mobile intermediate decay products of {sup 238}U. Emplacement of the Nipissing diabase may have been responsible for producing the bitumen and, indirectly, for its enrichment in {sup 206}Pb as a result of outgassing of {sup 222}Rn.

Mossman, D.J. [Mount Allison Univ., Sackville (Canada)] [Mount Allison Univ., Sackville (Canada); Nagy, B. [Univ. of Arizona, Tucson (United States)] [Univ. of Arizona, Tucson (United States); Davis, D.W. [Royal Ontario Museum, Toronto, Ontario (Canada)] [Royal Ontario Museum, Toronto, Ontario (Canada)

1993-07-01

289

Uranium droplet core nuclear rocket  

NASA Technical Reports Server (NTRS)

Uranium droplet nuclear rocket is conceptually designed to utilize the broad temperature range ofthe liquid phase of metallic uranium in droplet configuration which maximizes the energy transfer area per unit fuel volume. In a baseline system dissociated hydrogen at 100 bar is heated to 6000 K, providing 2000 second of Isp. Fission fragments and intense radian field enhance the dissociation of molecular hydrogen beyond the equilibrium thermodynamic level. Uranium droplets in the core are confined and separated by an axisymmetric vortex flow generated by high velocity tangential injection of hydrogen in the mid-core regions. Droplet uranium flow to the core is controlled and adjusted by a twin flow nozzle injection system.

Anghaie, Samim

1991-01-01

290

Multifunctional inorganic-organic hybrid nanospheres for rapid and selective luminescence detection of TNT in mixed nitroaromatics via magnetic separation.  

PubMed

Rapid, sensitive and selective detection of 2,4,6-trinitrotoluene (TNT) in aqueous solution differentiating from other nitroaromatics and independent of complicated instruments is in high demand for public safety and environmental monitoring. Despite of many methods for TNT detection, it is hard to differentiate TNT from 2,4,6-trinitrophenol (TNP) due to their highly similar structures and properties. In this work, via a simple and versatile method, LaF3?Ce(3+)-Tb(3+)and Fe3O4 nanoparticle-codoped multifunctional nanospheres were prepared through self-assembly of the building blocks. The luminescence of these nanocomposites was dramatically quenched via adding nitroaromatics into the aqueous solution. After the magnetic separation, however, the interference of other nitroaromatics including 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), and nitrobenzene (NB) was effectively overcome due to the removal of these coexisting nitroaromatics from the surface of nanocomposites. Due to the formation of TNT(-)-RCONH3(+), the TNT was attached to the surface of the nanocomposites and was quantitatively detected by the postexposure luminescence quenching. Meanwhile, the luminescence intensity is negatively proportional to the concentration of TNT in the range of 0.01-5.0 ?g/mL with the 3? limit of detection (LOD) of 10.2 ng/mL. Therefore, the as-developed method provides a novel strategy for rapid and selective detection of TNT in the mixture solution of nitroaromatics by postexposure luminescence quenching. PMID:24148441

Ma, Yingxin; Huang, Sheng; Wang, Leyu

2013-11-15

291

Depleted Uranium  

MedlinePLUS

... Military Sexual Trauma Radiation Chemical, Biological, and Radiological Weapons Cold Injury Hearing Impairment Visual Impairment Former Prisoners ... from natural uranium used in nuclear reactors or weapons leaves “depleted” uranium. DU has 40 percent less ...

292

300 Area Uranium Stabilization Through Polyphosphate Injection: Final Report  

SciTech Connect

The objective of the treatability test was to evaluate the efficacy of using polyphosphate injections to treat uranium-contaminated groundwater in situ. A test site consisting of an injection well and 15 monitoring wells was installed in the 300 Area near the process trenches that had previously received uranium-bearing effluents. This report summarizes the work on the polyphosphate injection project, including bench-scale laboratory studies, a field injection test, and the subsequent analysis and interpretation of the results. Previous laboratory tests have demonstrated that when a soluble form of polyphosphate is injected into uranium-bearing saturated porous media, immobilization of uranium occurs due to formation of an insoluble uranyl phosphate, autunite [Ca(UO2)2(PO4)2•nH2O]. These tests were conducted at conditions expected for the aquifer and used Hanford soils and groundwater containing very low concentrations of uranium (10-6 M). Because autunite sequesters uranium in the oxidized form U(VI) rather than forcing reduction to U(IV), the possibility of re-oxidation and subsequent re-mobilization is negated. Extensive testing demonstrated the very low solubility and slow dissolution kinetics of autunite. In addition to autunite, excess phosphorous may result in apatite mineral formation, which provides a long-term source of treatment capacity. Phosphate arrival response data indicate that, under site conditions, the polyphosphate amendment could be effectively distributed over a relatively large lateral extent, with wells located at a radial distance of 23 m (75 ft) reaching from between 40% and 60% of the injection concentration. Given these phosphate transport characteristics, direct treatment of uranium through the formation of uranyl-phosphate mineral phases (i.e., autunite) could likely be effectively implemented at full field scale. However, formation of calcium-phosphate mineral phases using the selected three-phase approach was problematic. Although amendment arrival response data indicate some degree of overlap between the reactive species and thus potential for the formation of calcium-phosphate mineral phases (i.e., apatite formation), the efficiency of this treatment approach was relatively poor. In general, uranium performance monitoring results support the hypothesis that limited long-term treatment capacity (i.e., apatite formation) was established during the injection test. Two separate overarching issues affect the efficacy of apatite remediation for uranium sequestration within the 300 Area: 1) the efficacy of apatite for sequestering uranium under the present geochemical and hydrodynamic conditions, and 2) the formation and emplacement of apatite via polyphosphate technology. In addition, the long-term stability of uranium sequestered via apatite is dependent on the chemical speciation of uranium, surface speciation of apatite, and the mechanism of retention, which is highly susceptible to dynamic geochemical conditions. It was expected that uranium sequestration in the presence of hydroxyapatite would occur by sorption and/or surface complexation until all surface sites have been depleted, but that the high carbonate concentrations in the 300 Area would act to inhibit the transformation of sorbed uranium to chernikovite and/or autunite. Adsorption of uranium by apatite was never considered a viable approach for in situ uranium sequestration in and of itself, because by definition, this is a reversible reaction. The efficacy of uranium sequestration by apatite assumes that the adsorbed uranium would subsequently convert to autunite, or other stable uranium phases. Because this appears to not be the case in the 300 Area aquifer, even in locations near the river, apatite may have limited efficacy for the retention and long-term immobilization of uranium at the 300 Area site..

Vermeul, Vincent R.; Bjornstad, Bruce N.; Fritz, Brad G.; Fruchter, Jonathan S.; Mackley, Rob D.; Newcomer, Darrell R.; Mendoza, Donaldo P.; Rockhold, Mark L.; Wellman, Dawn M.; Williams, Mark D.

2009-06-30

293

Novel microorganism for selective separation of coal from ash and pyrite. Seventh quarterly technical progress report, April 1, 1995--June 30, 1995  

SciTech Connect

The selective separation of pyrite and ash-forming minerals from coal can be accomplished by flotation, agglomeration and selective flocculation. The methods currently used for selective flocculation of coals include addition of natural or synthetic polymeric flocculants along with precise pH control. In some cases, these flocculants are nonselective or work imperfectly. It is known that many highly charged planktonic algae and bacteria will adhere to certain solid surfaces if the charge or hydrophobic interaction between the organism and the solids are favorable for adhesion. The resultant microorganism-mineral entities, if formed, can flocculate and can be separated. In addition, many living organisms produce extracellular biopolymers that can also cause flocculation. The microorganism, M. phlei, has the properties of being both highly charged and highly hydrophobic. The aim of the present investigation is to study the effectiveness of M. phlei and biopolymers derived from the organism for selective flocculation and separation of fine coal from pyrite and ash.

Misra, M.; Smith, R.W.; Raichur, A.M.

1996-12-31

294

SOME DATE ON THE ANALYSIS OF URANIUM, THORIUM, AND ZIRCONIUM  

Microsoft Academic Search

Considering the physicochemical conditions for tributyl phosphate (TBP) ; uranium extraction, an optimum nitrate concentration of the aqueous phase is ; found, in which uranium separation by single extraction amounts virtually to 100%. ; The extraction is carried out in TBP-petrol solution and the uranium is re-; extracted in a dilute ammonium carbonate solution. The uranium content can be ;

G. Almassy; M. Oerdoegh; A. Schneer

1958-01-01

295

Removal of uranium from aqueous HF solutions  

DOEpatents

This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

Pulley, Howard (West Paducah, KY) [West Paducah, KY; Seltzer, Steven F. (Paducah, KY) [Paducah, KY

1980-01-01

296

Separation of Selected Bile Acids by TLC. IX. Separation on Silica Gel 60 and on Silica Gel 60F254 Aluminum Plates Impregnated with Cu(II), Ni(II), Fe(II), and Mn(II) Cations  

Microsoft Academic Search

Seven selected bile acids: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC) were separated using adsorption TLC on aluminum plates precoated with silica gel 60 and on aluminum plates precoated with silica gel 60F254. The plates were impregnated with 1%, 2.5%, and 5% aqueous solutions of

M. Do?owy

2007-01-01

297

Oxidation states of uranium in depleted uranium particles from Kuwait  

Microsoft Academic Search

The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based ?-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to ?-XANES, DU particles ranging from submicrons to several hundred micrometers were observed. The median particle size depended on sources

B. Salbu; K. Janssens; O. C. Lind; K. Proost; L. Gijsels; P. R. Danesi

2004-01-01

298

Determination of molybdenum and uranium in biological materials by radiochemical neutron activation analysis  

Microsoft Academic Search

Recently developed radiochemical separation scheme for the simultaneous detemination of trace amounts of molybdenum and uranium in biological materials by NAA has been further refined and used for the detemination of these elements in several certified reference materials. The method assures very selective and quantitative separation of the indicator radionuclides:99Mo-99mTc and239Np from practically all accompanying activities followed by almost interference-free

B. Danko; R. Dybczyfiski

1997-01-01

299

Laser Isotope Separation  

Microsoft Academic Search

A brief background on the history and motivation of laser isotope separation is presented. Methods of molecular laser isotope separation are reviewed, and the Los Alamos process for separation of uranium isotopes as well as the general problems with this approach are covered. A short summary on critical uv cross-section-enhancement results is given and the implications of infrared cross-section dependence

Reed J. Jensen; J. Al Sullivan; Frank T. Finch

1980-01-01

300

Novel microorganism for selective separation of coal from ash and pyrite. Third quarterly technical progress report, March 1, 1994--May 31, 1994  

SciTech Connect

The selective separation of pyrite and ash-forming minerals from coal can be accomplished by flotation, agglomeration and selective flocculation. The methods currently used for selective flocculation of coals include addition of natural or synthetic polymeric flocculants along with precise pH control. In some cases, these flocculants are nonselective or work imperfectly. It is known that many highly charged planktonic algae and bacteria will adhere to certain solid surface if the charge or hydrophobic interaction between the organism and the solids are favorable for adhesion. The resultant microorganism-mineral entities if formed can flocculate and can be separated. In addition, many living organism produce extracellular biopolymers that can also cause flocculation. The microorganism, M. phlei, has the properties of being both highly charged and highly hydrophobic. The aim of the present investigation is to study the effectiveness of M. phlei and biopolymers derived from the organism for selective flocculation of fine coal from ash and pyrite.

Misra, M.; Smith, R.W.; Raichur, A.M.

1994-11-01

301

Separation of H 2 \\/CO by the selective sorption property of H 3 PMo 12 O 40 embedded in polyvinylalcohol membrane  

Microsoft Academic Search

H2 and CO permeabilities through H3PMo12O40-blended polyvinylalcohol membrane and catalyst-free polyvinylalcohol membrane were measured. The blended membrane showed\\u000a better selectivity and higher permeation flux of H2 than the catalyst-free polyvinylalcohol membrane. Its enhanced H2 separation ability was mainly due to the selective sorption property of PMo embedded in the polyvinylalcohol membrane.

Jong Koog Lee; In Kyu Song; Wha Young Lee

1995-01-01

302

Uranium extraction selectivities of dibutyl carbitol and tributyl phosphate in the system UO{sub 2}(NO{sub 3}){sub 2}-HNO{sub 3}-H{sub 2}O-Al(NO{sub 3}){sub 3}-solvent  

SciTech Connect

Historically, both the BUTEX (dibutyl carbitol-based) and PUREX (tributyl phosphate-based) processes have been used for uranium recovery and purification. Currently, BUTEX- and PUREX-type extraction processes are being used in series for recovery of isotopically enriched uranium at the Oak Ridge Y-12 Plant. The use of two solvents is predicated on the differing selectivities of each with regard to the contaminant elements present in the uranium source stream. As part of efforts to streamline plant operations in response to decreasing throughput requirements, the Y-12 Development Division is evaluating options for converting the existing two-solvent operation to a single-solvent process. At the request of the Y-12 Development Division, the Robotics and Process Division at the Oak Ridge National Laboratory has undertaken evaluation of solvents for use in a single-solvent recovery process. Initial efforts have been directed toward development of a single-solvent, dibutyl carbitol- or tributyl phosphate-based process that produces a product with purity equal to or exceeding what is currently obtained in the two-cycle, two-solvent operation. The test effort has involved both laboratory equilibrium determinations and engineering-scale process demonstrations in multistage flowsheets using centrifugal solvent extraction contactors. Excellent uranium recovery results have been obtained from both dibutyl carbitol- and tributyl phosphate-based solvent extraction flowsheets. Contaminant rejection performance by the two solvents is similar for many of the elements considered. Extraction of some contaminant elements by tributyl phosphate is significant enough to conclude that the solvent is not as selective for uranium as is dibutyl carbitol. This determination does not necessarily eliminate tributyl phosphate from consideration for use in a single-solvent process but does indicate a need for effective scrubbing of contaminants from uranium-loaded tributyl phosphate, possibly by partial reflux of the purified, aqueous uranyl nitrate product solution.

Birdwell, J.F. [Oak Ridge National Lab., TN (United States). Robotics and Process Systems Div.] [Oak Ridge National Lab., TN (United States). Robotics and Process Systems Div.

1999-04-01

303

Neutron-rich isotope production using a uranium carbide - carbon nanotubes SPES target prototype  

NASA Astrophysics Data System (ADS)

The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community.

Corradetti, S.; Biasetto, L.; Manzolaro, M.; Scarpa, D.; Carturan, S.; Andrighetto, A.; Prete, G.; Vasquez, J.; Zanonato, P.; Colombo, P.; Jost, C. U.; Stracener, D. W.

2013-05-01

304

Surface chemical studies on selective separation of pyrite and galena in the presence of bacterial cells and metabolic products of Paenibacillus polymyxa  

Microsoft Academic Search

Selective separation of pyrite and galena from mixture of the two minerals was achieved through interaction with cells and metabolic products from a culture of Paenibacillus polymyxa. Adsorption of cells and metabolic products onto minerals and electrokinetic studies of minerals after interaction with cells and metabolic products were carried out to examine the resulting surface modification on the mineral surfaces.

Partha Patra; K. A. Natarajan

2006-01-01

305

Biotin-conjugated N-methylisatoic anhydride: a chemical tool for nucleic acid separation by selective 2'-hydroxyl acylation of RNA.  

PubMed

An isatoic anhydride derivative conjugated to a biotin and a disulfide linker was specifically designed for the separation of nucleic acids. Starting from a DNA-RNA mixture, a selective 2'-hydroxyl acylation of RNAs followed by capture with streptavidin-coated magnetic beads and cleavage of the disulfide led to elution of RNAs. PMID:24752374

Ursuegui, S; Chivot, N; Moutin, S; Burr, A; Fossey, C; Cailly, T; Laayoun, A; Fabis, F; Laurent, A

2014-06-01

306

The use of amphoteric ion exchange resin for the selective separation of cadmium from other radioelements present in neutron irradiated biological materials  

Microsoft Academic Search

A new method for the selective radiochemical separation of cadmium from other elements, present in biological materials, using amphoteric ion exchange resin Retardion 11A8 has been elaborated. Cadmium can be taken up by the resin either as anionic chloride complexes or cationic ammine complexes, depending on the composition of the eluent, exploiting both cation and anion exchange functions of the

R. Dybczy?ski; Z. Samczy?ski

1991-01-01

307

Selective separation and determination of scandium from yttrium and lanthanides in red mud by a combined ion exchange\\/solvent extraction method  

Microsoft Academic Search

Scandium, existing in economically interesting concentrations, in red mud, the byproduct of the alumina production, could be selectively separated from the main and minor elements, as well as from yttrium and the lanthanides by the development of a combined ion exchange-solvent extraction method. After a suitable borate\\/carbonate fusion of red mud, the sample solution was passed through the ion exchanger

M. Ochsenkühn-Petropulu; Th. Lyberopulu; G. Parissakis

1995-01-01

308

A combination between membrane selectivity and photoelectrochemistry to the separation of copper, zinc and nickel in aqueous solutions  

Microsoft Academic Search

The transport phenomena through ion exchange membrane may be improved by the application of different forces inside or outside the systems. The electrical current, produced by synthetic photo electrode, is applied to enhance the separation of metallic ions. The cation exchange membrane placed between the two compartments permitted the separation and concentration of the ions M2+ (=Cu2+, Zn2+ and Ni2+).

Mourad Amara; Hacène Kerdjoudj; Aissa Bouguelia; Mohamed Trari

2008-01-01

309

Corrosion-resistant uranium  

DOEpatents

The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

Hovis, Jr., Victor M. (Kingston, TN); Pullen, William C. (Knoxville, TN) [Knoxville, TN; Kollie, Thomas G. (Oak Ridge, TN) [Oak Ridge, TN; Bell, Richard T. (Knoxville, TN) [Knoxville, TN

1983-01-01

310

Corrosion-resistant uranium  

DOEpatents

The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

1981-10-21

311

INFORMATION: Management Alert on Environmental Management's Select Strategy for Disposition of Savannah River Site Depleted Uranium Oxides  

SciTech Connect

The Administration and the Congress, through policy statements and passage of the American Recovery and Reinvestment Act of 2009 (Recovery Act), have signaled that they hope that proactive actions by agency Inspectors General will help ensure that Federal Recovery Act activities are transparent, effective and efficient. In that context, the purpose of this management alert is to share with you concerns that have been raised to the Office of Inspector General regarding the planned disposition of the Savannah River Site's (SRS) inventory of Depleted Uranium (DU) oxides. This inventory, generated as a by-product of the nuclear weapons production process and amounting to approximately 15,600 drums of DU oxides, has been stored at SRS for decades. A Department source we deem reliable and credible recently came to the Office of Inspector General expressing concern that imminent actions are planned that may not provide for the most cost effective disposition of these materials. During April 2009, the Department chose to use funds provided under the Recovery Act to accelerate final disposition of the SRS inventory of DU oxides. After coordination with State of Utah regulators, elected officials and the U.S. Nuclear Regulatory Commission, the Department initiated a campaign to ship the material to a facility operated by EnergySolutions in Clive, Utah. Although one shipment of a portion of the material has already been sent to the EnergySolutions facility, the majority of the product remains at SRS. As had been planned, both for the shipment already made and those planned in the near term, the EnergySolutions facility was to have been the final disposal location for the material. Recently, a member of Congress and various Utah State officials raised questions regarding the radioactive and other constituents present in the DU oxides to be disposed of at the Clive, Utah, facility. These concerns revolved around the characterization of the material and its acceptability under existing licensing criteria. As a consequence, the Governor of Utah met with Department officials to voice concerns regarding further shipments of the material and to seek return of the initial shipment of DU oxides to SRS. Utah's objections and the Department's agreement to accede to the State's demands effectively prohibit the transfer of the remaining material from South Carolina to Utah. In response, the Department evaluated its options and issued a draft decision paper on March 1, 2010, which outlined an alternative for temporary storage until the final disposition issue could be resolved. Under the terms of the proposed option, the remaining shipments from SRS are to be sent on an interim basis to a facility owned by Waste Control Specialists (WCS) in Andrews, Texas. Clearly, this choice carries with it a number of significant logistical burdens, including substantial additional costs for, among several items, repackaging at SRS, transportation to Texas, storage at the interim site, and, repackaging and transportation to the yet-to-be-determined final disposition point. The Department source expressed the concern that the proposal to store the material on an interim basis in Texas was inefficient and unnecessary, asserting: (1) that the materials could remain at SRS until a final disposition path is identified, and that this could be done safely, securely and cost effectively; and, (2) that the nature of the material was not subject to existing compliance agreements with the State of South Carolina, suggesting the viability of keeping the material in storage at SRS until a permanent disposal site is definitively established. We noted that, while the Department's decision paper referred to 'numerous project and programmatic factors that make it impractical to retain the remaining inventory at Savannah River,' it did not outline the specific issues involved nor did it provide any substantive economic or environmental analysis supporting the need for the planned interim storage action. The only apparent driver in this case was a Recovery Act-related goal esta

None

2010-04-01

312

Laser isotope separation  

SciTech Connect

A brief background on the history and motivation of laser isotope separation is presented. Methods of molecular laser isotope separation are reviewed, and the Los Alamos process for separation of uranium isotopes as well as the general problems with this approach are covered. A short summary on critical uv cross-section-enhancement results is given and the implications of infrared cross-section dependence on laser fluence is discussed. The laser requirements for the LASL process and the projected economics for this process are presented. The future prospects for molecular laser isotope separation as well as some speculation on general advances in photochemistry are presented.

Jensen, R.J.; Sullivan, J.A.; Finch, F.T.

1980-04-01

313

Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Lowman, Idaho: Remedial action selection report for the Lowman UMTRA project site, Idaho. Final report  

SciTech Connect

The inactive uranium mill tailings site near Lowman, Idaho, was designated as one of 24 abandoned uranium tailings sites to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE`s remedial action plan and certify that the remedial action complies with the standards promulgated by the US Environmental Protection Agency (EPA). The remedial action plan (RAP), which includes this remedial action selection report (RAS), has been developed to serve a two-fold purpose. First, it describes the activities that are proposed by the DOE to accomplish long-term stabilization and control of residual radioactive materials at the inactive uranium processing site near Lowman, Idaho. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Idaho, and the NRC, becomes Appendix B of the Cooperative Agreement (No. DE-FC04-85AL20535) between the DOE and the State of Idaho.

Matthews, M.L. [USDOE Albuquerque Field Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office; Nagel, J. [Idaho Dept. of Health and Welfare, Boise, ID (United States). Div. of Environmental Quality

1991-09-01

314

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Falls City, Texas. Remedial action selection report: Attachment 2, Geology report; Attachment 3, Groundwater hydrology report; Attachment 4, Water resources protection strategy: Final report  

SciTech Connect

The uranium processing site near Falls City, Texas, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under Title I of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE`s remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). The RAP, which includes this summary remedial action selection report (RAS), serves a two-fold purpose. First, it describes the activities proposed by the DOE to accomplish long-term stabilization and control of the residual radioactive materials at the inactive uranium processing site near Falls City, Texas. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Texas, and the NRC, becomes Appendix B of the Cooperative Agreement between the DOE and the State of Texas.

Chernoff, A.R. [USDOE Albuquerque Field Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office; Lacker, D.K. [Texas State Dept. of Health, Austin, TX (United States). Bureau of Radiation Control

1992-09-01

315

Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Lowman, Idaho: Remedial action selection report for the Lowman UMTRA project site, Idaho  

SciTech Connect

The inactive uranium mill tailings site near Lowman, Idaho, was designated as one of 24 abandoned uranium tailings sites to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's remedial action plan and certify that the remedial action complies with the standards promulgated by the US Environmental Protection Agency (EPA). The remedial action plan (RAP), which includes this remedial action selection report (RAS), has been developed to serve a two-fold purpose. First, it describes the activities that are proposed by the DOE to accomplish long-term stabilization and control of residual radioactive materials at the inactive uranium processing site near Lowman, Idaho. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Idaho, and the NRC, becomes Appendix B of the Cooperative Agreement (No. DE-FC04-85AL20535) between the DOE and the State of Idaho.

Matthews, M.L. (USDOE Albuquerque Field Office, NM (United States). Uranium Mill Tailings Remedial Action Project Office); Nagel, J. (Idaho Dept. of Health and Welfare, Boise, ID (United States). Div. of Environmental Quality)

1991-09-01

316

Enhanced Control of PWR Primary Coolant Water Chemistry Using Selective Separation Systems for Recovery and Recycle of Enriched Boric Acid  

SciTech Connect

The objective of this project is to develop systems that will allow for increased nuclear energy production through the use of enriched fuels. The developed systems will allow for the efficient and selective recover of selected isotopes that are additives to power water reactors' primary coolant chemistry for suppression of corrosion attack on reactor materials.

Ken Czerwinski; Charels Yeamans; Don Olander; Kenneth Raymond; Norman Schroeder; Thomas Robison; Bryan Carlson; Barbara Smit; Pat Robinson

2006-02-28

317

Separations of corticosteroids using electrochemically modulated liquid chromatography: Selectivity enhancements at a porous graphitic carbon stationary phase  

SciTech Connect

Electrochemically modulated liquid chromatography has been applied to the separation of a mixture of structurally similar corticosteroids (i.e., prednisone, prednisolone, cortisone, and hydrocortisone) using a porous graphitic carbon stationary phase. Changes in the voltage applied to the column markedly affected the efficiency as well as the elution order of the separation, with the mixture fully resolved at large negative values of applied potential. Mechanistic aspects in terms of the influence of changes in the applied voltage on the extent of the interactions between these analytes and the stationary phase are briefly discussed. 19 refs., 2 figs.

Ting, E.Y.; Porter, M.D. [Ames Lab., IA (United States)] [Ames Lab., IA (United States); [Iowa State Univ., Ames, IA (United States)

1997-02-15

318

Selective Eu(III) Electro?Reduction and Subsequent Separation of Eu(II) from Rare Earths(III) via HDEHP Impregnated Resin  

Microsoft Academic Search

Eu(III) was selectively reduced to Eu(II) at three?dimensional glassy carbon cathode in 0.01 mol · dm hydrochloric acid medium. Eu(III) reduction took place after all the dissolved oxygen was reduced and then proceeded steadily. Separation of Eu(II) from trivalent rare earths (La, Ce, Sm, Gd, Er, Yb) was carried out using a novel impregnated resin based on bis(2?ethylhexy1)phosphoric acid. Eu(II) showed

Ludek Jelinek; Yuezhou Wei; Tsuyoshi Arai; Mikio Kumagai

2007-01-01

319

Uranium Reduction  

SciTech Connect

The dramatic decrease in solubility accompanying thereduction of U(VI) to U(IV), producing the insoluble mineral uraninite,has been viewed as a potential mechanism for sequestration of environmentaluranium contamination. In the past 15 years, it has been firmlyestablished that a variety of bacteria exhibit this reductive capacity.To obtain an understanding of the microbial metal metabolism, to developa practical approach for the acceleration of in situ bioreduction, and topredict the long-term fate of environmental uranium, several aspects ofthe microbial process have been experimentally explored. This reviewbriefly addresses the research to identify specific uranium reductasesand their cellular location, competition between uranium and otherelectron acceptors, attempts to stimulate in situ reduction, andmechanisms of reoxidation of reduced uranium minerals.

Wall, J.D.; Krumholz, L.R.

2007-04-02

320

Separated Families and Children Who Refuse Access to a Parent. Unit for Child Studies Selected Papers Number 33.  

ERIC Educational Resources Information Center

On the whole, professionals agree that there is an advantage in both parents having access to the child or children after separation. This paper provides (1) an overview of the controversy over the value of such access; (2) a description of various contexts of access disputes and perspectives involved in the assessment of access situations; (3) a…

Renouf, Emilia

321

Selective separation and co-culture of cells by photo-induced enhancement of cell adhesion (PIECA).  

PubMed

Taking advantage of the phenomenon that animal cells adhering to a culture substrate are temporarily immobilized by light irradiation, we established a technique to manipulate the cells adhering to a culture substrate under microscopic observation. Using this technique, we demonstrated a separation of cells adhering to a culture substrate and fabrication of an elaborately patterned co-culture system. PMID:18949751

Edahiro, Jun-Ichi; Sumaru, Kimio; Ooshima, Yuki; Kanamori, Toshiyuki

2009-03-01

322

Automated System for Selective Fission Product Separations Applied to the Study of exp 113-115 Pd.  

National Technical Information Service (NTIS)

A microcomputer-controlled radiochemical separation system has been developed for the isolation and study of fission products with half-lives of greater than or equal to 10 s. The system, based upon solvent extraction with three centrifugal contactors cou...

D. H. Meikrantz

1980-01-01

323

Investigation of the particle selectivity of a traveling potential wave; neon isotope separation with the Solitron process. Final report  

SciTech Connect

The specific goal of this three year effort was to investigate this novel isotope separation process itself: to determine whether isotopes could indeed be separated and, if so, with what limitations--space charge effects, instabilities, and, in particular, with what throughput limitations. Termed the Solitron process, the concept is based on the strong isotopic variation in wave/ion interaction for a potential wave passing through an ion beam when the wave speed is near the ion speed. The ion`s charge-to-mass ratio determines not only which ions are picked up by the wave but also the final energy of those ions that are picked up (accelerated to a higher energy); thus, this method can be used for isotope separation. Much progress was made regarding separation and throughput, concluding that separation works well in conjunction with electrostatic focusing used to obtain enough throughput (enough beam current) to make a practical device. The next step would likely be a production device, although development of an appropriate metal ion source would be useful. Funding is an issue; development cost estimates run around two million dollars for a market only several times that cost. Although there is much concern about the future supply of isotopes such as could be produced by the Solitron process, as well as costs, at present the supply from Oak Ridge and Russian sources is adequate for US needs. Should demand grow, these LDRD studies would strongly support proposals for further development of this Solitron process and help assure its likely success. For example, a point design for a magnesium mission was formulated to obtain a consistent set of design numbers that would optimize performance without pushing any constraints seen in these studies. A similar design could be formulated for other missions (magnesium was just a convenient target).

Lowder, R.S.

1994-07-26

324

Uranium chloride extraction of transuranium elements from LWR fuel  

DOEpatents

A process of separating transuranium actinide values from uranium values present in spent nuclear oxide fuels containing rare earth and noble metal fission products as well as other fission products is disclosed. The oxide fuel is reduced with Ca metal in the presence of Ca chloride and a U-Fe alloy which is liquid at about 800.degree. C. to dissolve uranium metal and the noble metal fission product metals and transuranium actinide metals and rare earth fission product metals leaving Ca chloride having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein. The Ca chloride and CaO and the fission products contained therein are separated from the U-Fe alloy and the metal values dissolved therein. The U-Fe alloy having dissolved therein reduced metals from the spent nuclear fuel is contacted with a mixture of one or more alkali metal or alkaline earth metal halides selected from the class consisting of alkali metal or alkaline earth metal and Fe or U halide or a combination thereof to transfer transuranium actinide metals and rare earth metals to the halide salt leaving the uranium and some noble metal fission products in the U-Fe alloy and thereafter separating the halide salt and the transuranium metals dissolved therein from the U-Fe alloy and the metals dissolved therein.

Miller, William E. (Naperville, IL); Ackerman, John P. (Downers Grove, IL); Battles, James E. (Oak Forest, IL); Johnson, Terry R. (Wheaton, IL); Pierce, R. Dean (Naperville, IL)

1992-01-01

325

Uranium chloride extraction of transuranium elements from LWR fuel  

DOEpatents

A process of separating transuranium actinide values from uranium values present in spent nuclear oxide fuels containing rare earth and noble metal fission products as well as other fission products is disclosed. The oxide fuel is reduced with Ca metal in the presence of Ca chloride and a U-Fe alloy which is liquid at about 800 C to dissolve uranium metal and the noble metal fission product metals and transuranium actinide metals and rare earth fission product metals leaving Ca chloride having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein. The Ca chloride and CaO and the fission products contained therein are separated from the U-Fe alloy and the metal values dissolved therein. The U-Fe alloy having dissolved therein reduced metals from the spent nuclear fuel is contacted with a mixture of one or more alkali metal or alkaline earth metal halides selected from the class consisting of alkali metal or alkaline earth metal and Fe or U halide or a combination thereof to transfer transuranium actinide metals and rare earth metals to the halide salt leaving the uranium and some noble metal fission products in the U-Fe alloy and thereafter separating the halide salt and the transuranium metals dissolved therein from the U-Fe alloy and the metals dissolved therein. 1 figure.

Miller, W.E.; Ackerman, J.P.; Battles, J.E.; Johnson, T.R.; Pierce, R.D.

1992-08-25

326

Target synthesis of a novel porous aromatic framework and its highly selective separation of CO(2)/CH(4).  

PubMed

A novel porous aromatic framework based on tetra-(4-anilyl)-methane and cyanuric chloride has been designed and synthesized successfully, which possesses permanent porosity and high selectivity of CO2 towards CH4. PMID:23439946

Zhao, Huanyu; Jin, Zhao; Su, Hongmin; Zhang, Jinlei; Yao, Xiangdong; Zhao, Huijun; Zhu, Guangshan

2013-04-01

327

Reliability of selected procedures of stress inversion and data separation for inhomogeneous populations of calcite twins and striated faults: insights from numerical experiments  

NASA Astrophysics Data System (ADS)

In the course of numerical experiments selected algorithms for stress tensor inversion and separation of heterogeneous populations of calcite twins and striated faults were tested. Artificial data sets were created in a manner simulating natural processes. They were composed of data, dynamically compatible with one or two stress tensors and chaotic “noise” imitating natural imperfections. For calcite twins the classical inversion procedure is considered valid, with restrictions regarding a high proportion of chaotic data, when shape ratio of the stress tensor ? is poorly constrained. The algorithm of Etchecopar (1984 fide Tourneret and Laurent in Tectonophysics 180:287-302, 1990) devised originally for calcite twins has been modified and applied to fault/slip data, facilitating a rejection of incompatible outliers. Two main classes of data separation procedures were tested: separation contemporary with inversion and separation prior to inversion, utilising hierarchical clustering. The separation contemporary with inversion performs moderately but often fails with complex calcite twin sets. The performance of hierarchical clustering is high, but only with a ? 1 orientation as a similarity criterion—the new strategy introduced in this contribution. For fault/slip data the hierarchical clustering with the right-dihedra construction as the similarity criterion (Nemcok et al. 1999) is satisfactory. Additionally, a new approach is proposed for fault/slip data, utilising principles of the classical algorithm for heterogeneous populations of calcite twins. Validated algorithms for striated faults were successfully applied to a natural data set from the Holy Cross Mts (central Poland).

G?ga?a, ?ukasz

2009-03-01

328

Transuranic separation using organophophorus extractants adsorbed onto superparamagnetic carriers.  

SciTech Connect

Polymeric coated ferromagnetic carriers with an absorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted by tributyl phosphate (TBP) are being evaluated for application in the separation and the recovery of low concentrations of americium, plutonium, and uranium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles and the complexed particles can be recovered from the solution using a magnet. Physical and chemical characterization of the extractant-absorbed particles were performed by gamma and liquid scintillation counting, scanning electron microscopic (SEM) micrograph, and other physical measurements. Plutonium, americium, and uranium separations have been performed at various HNO{sub 3} and HCl concentrations. Parameters were studied to determine the limitations and capacity of the process. The status of the chemistry and application of the process to Department of Energy (DOE) remediation efforts for actinide decontamination are discussed.

Nunez, L.

1998-10-07

329

Uranium industry annual 1994.  

National Technical Information Service (NTIS)

The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federa...

1995-01-01

330

Uranium Enrichment - ChemCases.com  

NSDL National Science Digital Library

Natural uranium contains 0.7205% of the U-235, the fissile isotope of uranium. There are a few U-234 atoms (0.0055%) in the remaining mass of U-238 (99.274%). Uranium-238 does not contribute to slow neutron fission; however, it does react with neutrons to form a fissile isotope of plutonium, Pu-239. Although U-235 and U-238 are chemically identical, they differ slightly in their physical properties, most importantly mass. This small mass difference allows the isotopes to be separated and makes it possible to increase ("enrich") the percentage of U-235 in uranium.

Settle, Frank

331

Use of ligand-modified micellar-enhanced ultrafiltration to selectively separate copper ions from wastewater streams.  

National Technical Information Service (NTIS)

The selective removal of target ions from an aqueous solution containing ions of like charge by ligand-modified micellar-enhanced ultrafiltration (LM-MEUF), is presented. In LM-MEUF, surfactant and specially tailored ligand are added to the contaminated s...

S. B. Shadizadeh

1992-01-01

332

Separating ISI and CCI in a two-step FIR Bezout equalizer for MIMO systems of frequency-selective channels  

Microsoft Academic Search

The use of multiple antennas at both the transmitter and the receiver in wireless communications implies a great channel capacity, but the signal detection is a crucial problem in achieving channel capacity, particularly in the general case of frequency selective channels, where both intersymbol interference (ISI) and cochannel interference (CCI) are significant. We show that ISI and CCI can be

Yiteng Huang; J. Benesty; Jingdong Chen

2004-01-01

333

Open Onlay Mesh Repair for Major Abdominal Wall Hernias with Selective Use of Components Separation and Fibrin Sealant  

Microsoft Academic Search

Background  The objective of the study was to reassess the efficacy of the open onlay technique for repair of major incisional hernias,\\u000a utilizing the modern adjuncts of components separation and fibrin sealant to reduce the principal complications of seroma\\u000a and recurrence. Major incisional hernias were defined as >10 cm transverse diameter.\\u000a \\u000a \\u000a \\u000a Methods  A prospective audit was applied to 116 patients undergoing open

Andrew N. Kingsnorth; M. Kamran Shahid; Aby J. Valliattu; Robert A. Hadden; Christine S. Porter

2008-01-01

334

Separation scheme for selective and quantitative isolation of cobalt from neutron-irradiated biological materials by ion exchange and extraction chromatography  

SciTech Connect

Highly reliable radiochemical separation scheme for selective and quantitative isolation of trace amounts of cobalt from neutron-irradiated biological materials was elaborated. The method consists in wet-ashing of the sample with HNO{sub 3} + HClO{sub 4} (1:1) mixture plus vanadium salt (oxidation catalyst), removal of silica by evaporation with HF and separation of cobalt from accompanying ions successively on 3 columns with Dowex 1-X8[Cl{sup -}] from 0.5 M HCl, Dowex 1-X8[Cl{sup -}] from 8 M HCl + 2 M MgCl{sub 2} and tri-n-octylphosphine oxide (TOPO) supported on styrene-divinylbenzene copolymer, from 7 M HCl solution, respectively. Cobalt of very high radiochemical purity is finally recovered in 1.2 M HCl solution with practically 100% yield. The separation scheme is universally applicable, to biological samples of both animal and plant origin and was devised to become an integral part of the very accurate ({open_quotes}definitive{close_quotes}) method of cobalt determination by neutron activation analysis (NAA). Preliminary results on Co determination by NAA in some certified reference materials confirmed high reliability of the devised separation scheme.

Dybczynski, R.; Danko, B.; Maleszewska, H. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

1994-01-01

335

A generic analysis of energy use and solvent selection for CO2 separation from post-combustion flue gases  

USGS Publications Warehouse

A thermodynamic calculation was performed to determine the theoretical minimum energy used to separate CO2 from a coal combustion flue gas in a typical adsorption-desorption system. Under ideal conditions, the minimum energy required to separate CO2 from post-combustion flue gas and produce pure CO2 at 1 atmospheric pressure was only about 1183 kJ/kg CO2. This amount could double with the addition of the driving forces of mass and heat transfer and the adverse impacts of absorption heat release on adsorption capacity. Thermodynamic analyses were also performed for the aqueous amine-based absorption process. Two CO2 reaction mechanisms, the carbamate formation reaction with primary/secondary amines and the CO2 hydration reaction with tertiary amines, were included in the absorption reaction. The reaction heat, sensible heat, and stripping heat were all important to the total heat requirement. The heat use of an ideal tertiary amine amounted to 2786 kJ/kg, compared to 3211 kJ/kg for an ideal primary amine. The heat usage of an ideal amine was about 20% lower than that of commercially available amines. Optimizing the absorption process configuration could further reduce energy use. This is an abstract of a paper presented at the 2008 AIChE Spring National Meeting (New Orleans, LA 4/6-10/2008).

Lu, Y.; Chen, S.; Rostam-Abadi, M.

2008-01-01

336

Inorganic arsenic speciation in groundwater samples using electrothermal atomic spectrometry following selective separation and cloud point extraction.  

PubMed

A method has been developed for speciation of total, total inorganic and organic arsenic (As) species in groundwater samples. The inorganic species of As((III,V)) were separated from organic forms by adsorbing on alumina (Al(2)O(3)) whereas the organic As was eluted out. The retained inorganic As species was eluted by 0.2 M HCl. Then eluent As(III) and As(V) were formed as complexes with ammonium pyrrolidinedithiocarbamate (APDC) and molybdate, respectively. Then As(III)-PDC and As(V)-molybdate complexes were quantitatively extracted into a non-ionic surfactant Triton X-114. The total As was determined by conventional preconcentration procedures. The resulting solutions of each method were determined by ETAAS with modifier. The main factors affecting the separation and cloud point extraction (CPE) were investigated in detail. The limits of detection values were found as 0.04 and 0.20 µg L(-1) for As(III) and As(V), respectively, whereas limits of quantification were observed as 0.13 and 0.33 µg L(-1) for As(III) and As(V), respectively. Standard addition method confirmed the accuracy. The recoveries of As(III) and As(V) were found in the range of 98 - 99%. The proposed method was applied to groundwater samples collected from different areas of Sukkur district. PMID:21478622

Baig, Jameel A; Kazi, Tasneem G; Arain, Mohammad B; Shah, Abdul Q; Kandhro, Ghulam A; Afridi, Hassan I; Khan, Sumaira; Kolachi, Nida F; Wadhwa, Sham K

2011-01-01

337

Importance of MS selectivity and chromatographic separation in LC-MS/MS-based methods when investigating pharmaceutical metabolites in water. Dipyrone as a case of study.  

PubMed

Pharmaceuticals are emerging contaminants of increasing concern because of their presence in the aquatic environment and potential to reach drinking-water sources. After human and/or veterinary consumption, pharmaceuticals can be excreted in unchanged form, as the parent compound, and/or as free or conjugated metabolites. Determination of most pharmaceuticals and metabolites in the environment is commonly made by liquid chromatography (LC) coupled to mass spectrometry (MS). LC coupled to tandem MS is the technique of choice nowadays in this field. The acquisition of two selected reaction monitoring (SRM) transitions together with the retention time is the most widely accepted criterion for a safe quantification and confirmation assay. However, scarce attention is normally paid to the selectivity of the selected transitions as well as to the chromatographic separation. In this work, the importance of full spectrum acquisition high-resolution MS data using a hybrid quadrupole time-of-flight analyser and/or a suitable chromatographic separation (to reduce the possibility of co-eluting interferences) is highlighted when investigating pharmaceutical metabolites that share common fragment ions. For this purpose, the analytical challenge associated to the determination of metabolites of the widely used analgesic dipyrone (also known as metamizol) in urban wastewater is discussed. Examples are given on the possibilities of reporting false positives of dypirone metabolites by LC-MS/MS under SRM mode due to a wrong assignment of identity of the compounds detected. PMID:22899513

Ibáñez, M; Gracia-Lor, E; Sancho, J V; Hernández, F

2012-08-01

338

Achieving Diameter-Selective Separation of Single-Walled Carbon Nanobutes by Using Polymer Conformation-Confined Helical Cavity.  

SciTech Connect

A water-soluble poly[(m-phenylenevinylene)-alt-(p-phenylenevinylene)] (PmPV) 2 has been synthesized, which exhibits an unsymmetrical substitution pattern on the para-phenylene unit. With one substituent being hydrophilic while the other being hydrophobic, the polymer chain has a higher tendency to fold in aqueous solution, thereby promoting the helical conformation. The polymer is found to selectively disperse the SWNTs of small diameters (d=0.75-0.84 nm), in sharp contrast to PmPV 1 with a symmetrical substitution pattern. The intriguing diameter-based selectivity is believed to be associated with the confined helical conformation, which provides a suitable cavity to host the SWNT of proper sizes. The study thus provides a useful demonstration that the polymer conformation can have a profound impact on the SWNT sorting.

Chen, Yusheng [University of Akron; Xu, Yongqian [University of Akron; Perry, Kelly A [ORNL; Sokolov, Alexei P [ORNL; More, Karren Leslie [ORNL; Pang, Yi [University of Akron

2012-01-01

339

Preparation of a stationary phase with quaternary ammonium embedded group for selective separation of alkaloids based on ion-exclusion interaction.  

PubMed

A stationary phase (named QA C10) with quaternary ammonium embedded between a propyl and a decyl chain was synthesized by immobilization of N,N-dimethyldecylamine on chloropropyl-silica surface. A set of representative neutral, basic, and acidic compounds was employed to evaluate its chromatographic properties. The results illustrated that QA C10 was a mixed-mode stationary phase possessing both hydrophobic and ionic characteristics. The QA C10 stationary phase was further used for selective separation of alkaloids from Cortex phellodendri. Under acidic condition, alkaloids could be eluted in first 8 min, while other neutral and acidic fractions were retained better on QA C10 column. Then, obtained alkaloid fraction was analyzed by LC-MS/MS and 22 alkaloids were identified. Our study confirmed the advantages and application potential of the QA C10 stationary phase for alkaloids separation. PMID:23008235

Liu, Qiaoxia; Liang, Tu; Li, Kuiyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

2012-10-01

340

Long-Gradient Separations Coupled with Selected Reaction Monitoring for Highly Sensitive, Large Scale Targeted Protein Quantification in a Single Analysis  

SciTech Connect

Long-gradient separations coupled to tandem MS were recently demonstrated to provide a deep proteome coverage for global proteomics; however, such long-gradient separations have not been explored for targeted proteomics. Herein, we investigate the potential performance of the long-gradient separations coupled with selected reaction monitoring (LG-SRM) for targeted protein quantification. Direct comparison of LG-SRM (5 h gradient) and conventional LC-SRM (45 min gradient) showed that the long-gradient separations significantly reduced background interference levels and provided an 8- to 100-fold improvement in LOQ for target proteins in human female serum. Based on at least one surrogate peptide per protein, an LOQ of 10 ng/mL was achieved for the two spiked proteins in non-depleted human serum. The LG-SRM detection of seven out of eight endogenous plasma proteins expressed at ng/mL or sub-ng/mL levels in clinical patient sera was also demonstrated. A correlation coefficient of >0.99 was observed for the results of LG-SRM and ELISA measurements for prostate-specific antigen (PSA) in selected patient sera. Further enhancement of LG-SRM sensitivity was achieved by applying front-end IgY14 immunoaffinity depletion. Besides improved sensitivity, LG-SRM offers at least 3 times higher multiplexing capacity than conventional LC-SRM due to ~3-fold increase in average peak widths for a 300-min gradient compared to a 45-min gradient. Therefore, LG-SRM holds great potential for bridging the gap between global and targeted proteomics due to its advantages in both sensitivity and multiplexing capacity.

Shi, Tujin; Fillmore, Thomas L.; Gao, Yuqian; Zhao, Rui; He, Jintang; Schepmoes, Athena A.; Nicora, Carrie D.; Wu, Chaochao; Chambers, Justin L.; Moore, Ronald J.; Kagan, Jacob; Srivastava, Sudhir; Liu, Alvin Y.; Rodland, Karin D.; Liu, Tao; Camp, David G.; Smith, Richard D.; Qian, Weijun

2013-10-01

341

Magnetic Separation Device.  

National Technical Information Service (NTIS)

This invention pertains to magnetic separation devices and more particularly to; magnetic separation devices used to selectively remove magnetic bead-coated cells from tissues such as bone marrow or blood. Depletion of cell populations from boner marrow h...

G. M. Starken J. Cavin R. A. Quinnell C. A. Twigg D. P. Crawford

1985-01-01

342

Radiochemical scheme for the determination of molybdenum and uranium in biological materials by NAA  

Microsoft Academic Search

A new universal radiochemical separation scheme for selective and quantitative isolation of molybdenum and neptunium (formed from uranium), from neutron irradiated biological materials has been elaborated. The procedure is based on ion exchange and extraction chromatography with final fixation of molybdenum on a column with -benzoinoxime supported on Bio-Beads SM2 and neptunium on Dowex 1-X8 [No\\u000a3\\u000a–\\u000a]. The

B. Danko; R. Dybczy?ski

1995-01-01

343

Alga-Derived Substrates Select for Distinct Betaproteobacterial Lineages and Contribute to Niche Separation in Limnohabitans Strains?  

PubMed Central

We examined the proportions of major Betaproteobacteria subgroups within bacterial communities in diverse nonaxenic, monospecific cultures of algae or cyanobacteria: four species of cryptophyta (genera Cryptomonas and Rhodomonas), four species of chlorophyta (genera Pediastrum, Staurastrum, and Chlamydomonas), and two species of cyanobacteria (genera Dolichospermum and Aphanizomenon). In the cryptophyta cultures, Betaproteobacteria represented 48 to 71% of total bacteria, the genus Limnohabitans represented 18 to 26%, and the Polynucleobacter B subcluster represented 5 to 16%. In the taxonomically diverse chlorophyta group, the genus Limnohabitans accounted for 7 to 45% of total bacteria. In contrast, cyanobacterial cultures contained significantly lower proportions of the Limnohabitans bacteria (1 to 3% of the total) than the cryptophyta and chlorophyta cultures. Notably, largely absent in all of the cultures was Polynucleobacter necessarius (Polynucleobacter C subcluster). Subsequently, we examined the growth of Limnohabitans strains in the presence of different algae or their extracellular products (EPP). Two strains, affiliated with Limnohabitans planktonicus and Limnohabitans parvus, were separately inoculated into axenic cultures of three algal species growing in an inorganic medium: Cryptomonas sp., Chlamydomonas noctigama, and Pediastrum boryanum. The Limnohabitans strains cocultured with these algae or inoculated into their EPP consistently showed (i) pronounced population growth compared to the control without the algae or EPP and (ii) stronger growth stimulation of L. planktonicus than of L. parvus. Overall, growth responses of the Limnohabitans strains cultured with algae were highly species specific, which suggests a pronounced niche separation between two closely related Limnohabitans species likely mediated by different abilities to utilize the substrates produced by different algal species.

Simek, Karel; Kasalicky, Vojtech; Zapomelova, Eliska; Hornak, Karel

2011-01-01

344

Alga-derived substrates select for distinct Betaproteobacterial lineages and contribute to niche separation in Limnohabitans strains.  

PubMed

We examined the proportions of major Betaproteobacteria subgroups within bacterial communities in diverse nonaxenic, monospecific cultures of algae or cyanobacteria: four species of cryptophyta (genera Cryptomonas and Rhodomonas), four species of chlorophyta (genera Pediastrum, Staurastrum, and Chlamydomonas), and two species of cyanobacteria (genera Dolichospermum and Aphanizomenon). In the cryptophyta cultures, Betaproteobacteria represented 48 to 71% of total bacteria, the genus Limnohabitans represented 18 to 26%, and the Polynucleobacter B subcluster represented 5 to 16%. In the taxonomically diverse chlorophyta group, the genus Limnohabitans accounted for 7 to 45% of total bacteria. In contrast, cyanobacterial cultures contained significantly lower proportions of the Limnohabitans bacteria (1 to 3% of the total) than the cryptophyta and chlorophyta cultures. Notably, largely absent in all of the cultures was Polynucleobacter necessarius (Polynucleobacter C subcluster). Subsequently, we examined the growth of Limnohabitans strains in the presence of different algae or their extracellular products (EPP). Two strains, affiliated with Limnohabitans planktonicus and Limnohabitans parvus, were separately inoculated into axenic cultures of three algal species growing in an inorganic medium: Cryptomonas sp., Chlamydomonas noctigama, and Pediastrum boryanum. The Limnohabitans strains cocultured with these algae or inoculated into their EPP consistently showed (i) pronounced population growth compared to the control without the algae or EPP and (ii) stronger growth stimulation of L. planktonicus than of L. parvus. Overall, growth responses of the Limnohabitans strains cultured with algae were highly species specific, which suggests a pronounced niche separation between two closely related Limnohabitans species likely mediated by different abilities to utilize the substrates produced by different algal species. PMID:21873481

Simek, Karel; Kasalický, Vojt?ch; Zapom?lová, Eliska; Hornák, Karel

2011-10-01

345

Selective Separation of Scandium(III) and Yttrium(III) from other Rare Earth Elements using Cyanex302 as an Extractant  

Microsoft Academic Search

Liquid?liquid extraction and selective separation of scandium(III) and yttrium(III) with Cyanex302 (bis(2,4,4?trimethylpentyl)monothiophosphinic acid) has been carried out by controlling the aqueous phase pH. Scandium(III) and yttrium(III) were completely recovered from the organic phase using 5.0 M and 4.0 M nitric acid respectively and determined spectrophotometrically as their complexes with Arsenazo(III). The influence of extractant concentration, equilibration time, nature of diluents, stripping agents,

Manjusha Karve; Bhagyashree Vaidya

2008-01-01

346

Fabrication of dual-layer polyethersulfone (PES) hollow fiber membranes with an ultrathin dense-selective layer for gas separation  

Microsoft Academic Search

By using co-extrusion and dry-jet wet-spinning phase-inversion techniques with the aid of heat-treatment at 75°C, we have fabricated dual-layer polyethersulfone (PES) hollow fiber membranes with an ultrathin dense-selective layer of 407Å. To our best knowledge, this is the thinnest thickness that has ever been reported for dual-layer hollow fiber membranes. The dual-layer hollow fibers have an O2 permeance of 10.8GPU

Yi Li; Chun Cao; Tai-Shung Chung; Kumari P. Pramoda

2004-01-01

347

Remedial action plan and site design for stabilization of the inactive uranium processing site at Naturita, Colorado. Remedial Action Selection Report, Appendix B of Attachment 2: Geology report, Final  

SciTech Connect

The uranium processing site near Naturita, Colorado, is one of 24 inactive uranium mill sites designated to be cleaned up by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), 42 USC {section} 7901 et seq. Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE`s remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which describes the proposed remedial action for the Naturita site. An extensive amount of data and supporting information has been generated and evaluated for this remedial action. These data and supporting information are not incorporated into this single document but are included or referenced in the supporting documents. The RAP consists of this RAS and four supporting documents or attachments. This Attachment 2, Geology Report describes the details of geologic, geomorphic, and seismic conditions at the Dry Flats disposal site.

Not Available

1994-03-01

348

A NEW METHOD BASED ON PAPER CHROMATOGRAPHY FOR THE DETERMINATION OF URANIUM IN URANIUM MINERALS  

Microsoft Academic Search

A titraiion using ethylenediaminetetraacetate for uranium determination ; is described. Xylenol orange is used as indicator, This method makes possible ; the separation of uranium from other constituents of its mineral by paper ; chromatography, and subsequeat determination via the EDTA titration. The method ; is fully described. (J.R.D.);

I. I. M. Elbeih; M. A. Abou-Elnaga

1958-01-01

349

Rescuing a Treasure Uranium-233  

SciTech Connect

Uranium-233 (233U) is a synthetic isotope of uranium formed under reactor conditions during neutron capture by natural thorium (232Th). At high purities, this synthetic isotope serves as a crucial reference for accurately quantifying and characterizing natural uranium isotopes for domestic and international safeguards. Separated 233U is stored in vaults at Oak Ridge National Laboratory. These materials represent a broad spectrum of 233U from the standpoint isotopic purity the purest being crucial for precise analyses in safeguarding uranium. All 233U at ORNL currently is scheduled to be down blended with depleted uranium beginning in 2015. Such down blending will permanently destroy the potential value of pure 233U samples as certified reference material for use in uranium analyses. Furthermore, no replacement 233U stocks are expected to be produced in the future due to a lack of operating production capability and the high cost of returning to operation this currently shut down capability. This paper will describe the efforts to rescue the purest of the 233U materials arguably national treasures from their destruction by down blending.

Krichinsky, Alan M [ORNL; Goldberg, Dr. Steven A. [DOE SC - Chicago Office; Hutcheon, Dr. Ian D. [Lawrence Livermore National Laboratory (LLNL)

2011-01-01

350

Remedial Action Plan and Site Design for Stabilization of the Inactive Uranium Mill Tailings Site, Maybell, Colorado. Remedial action selection report: Attachment 2, Geology report, Final.  

National Technical Information Service (NTIS)

The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers (km)) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The de...

1994-01-01

351

Modified superparamagnetic nanocomposite microparticles for highly selective Hg(II) or Cu(II) separation and recovery from aqueous solutions.  

PubMed

The synthesis of a reusable, magnetically switchable nanocomposite microparticle, which can be modified to selectively extract and recover Hg(II) or Cu(II) from water, is reported. Superparamagnetic iron oxide (magnetite) nanoparticles act as the magnetic component in this system, and these nanoparticles were synthesized in a continuous way, allowing their large-scale production. A new process was used to create a silica matrix, confining the magnetite nanoparticles using a cheap silica source [sodium silicate (water glass)]. This results in a well-defined, filigree micrometer-sized nanocomposite via a fast, simple, inexpensive, and upscalable process. Hence, because of the ideal size of the resulting microparticles and their comparably large magnetization, particle extraction from fluids by low-cost magnets is achieved. PMID:22970866

Mandel, Karl; Hutter, Frank; Gellermann, Carsten; Sextl, Gerhard

2012-10-24

352

Speciation of chromium by selective separation and preconcentration of Cr(III) on an immobilized nanometer titanium dioxide microcolumn.  

PubMed

Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer-scale TiO2 particles) was prepared by a sol-gel method and characterized by X-ray diffraction and scanning electron microscopy. The adsorptive behavior of Cr(III) and Cr(VI) on immobilized nanometer TiO2 was assessed. Cr(III) was selectively sorbed on immobilized nanometer TiO2 in the pH range of 7-9, while Cr(VI) was found to remain in solution. A sensitive and selective method has been developed for the speciation of chromium in water samples using an immobilized nanometer TiO2 microcolumn and inductively coupled plasma atomic emission spectrometry. Under optimized conditions (pH 7.0, flow rate 2.0 mL/min), Cr(III) was retained on the column, then eluted with 0.5 mol/L HNO3 and determined by ICP-AES. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by ascorbic acid. The adsorption capacity of immobilized nanometer TiO2 for Cr(III) was found to be 7.04 mg/g. The detection limit for Cr(III) was 0.22 ng/mL and the RSD was 3.5% (n = 11, c = 100 ng/ mL) with an enrichment factor of 50. The proposed method has been applied to the speciation of chromium in water samples with satisfactory results. PMID:16524098

Liang, Pei; Ding, Qiong; Liu, Yan

2006-02-01

353

Application of two-dimensional selective-TOCSY HMBC for structure elucidation of impurities in mixture without separation.  

PubMed

In the pharmaceutical industry, regulatory expectations driven by patient safety considerations make structure elucidation of impurities at levels greater than 0.1% in the active pharmaceutical ingredient (API) of primary interest. Impurities can be generated from isomers in starting materials, or produced from different process steps toward the final API. Proton peaks belonging to different impurities could be potentially identified in the one-dimensional (1)H NMR spectrum, when evaluated in combination with two-dimensional (2-D) COSY and HSQC data. However, in 2-D HMBC data, correlation responses from different impurities may overlap with those from the major component, causing uncertainty of long-range proton to carbon correlations and quaternary carbon assignments. This observation prompts us to design the 2-D selective-TOCSY HMBC experiment to distinguish responses from different impurities in mixtures to obtain 2-D NMR data for each impurity, thus eliminating the use of a chromatographic isolation step to obtain material for NMR analysis. This methodology is demonstrated for structure elucidation of impurities ranging from 8.2% in the raw material to 0.4% in the API in this study, and would be particularly useful for industrial samples in which the solubility and availability of material are not an issue. PMID:23233169

Hwang, Tsang-Lin; Ronk, Michael; Milne, Jacqueline E

2013-02-01

354

Effect of stationary phase structure on retention and selectivity tuning in the high-throughput separation of tocopherol isomers by HPLC.  

PubMed

Four stationary phases containing different groups such as: C18, C30, alkylamide, and cholesterolic, were presented for simultaneous HPLC analysis of structural isomers of tocopherol. Especially, the influence of stationary phase structure and properties on tuning of the highly selective HPLC separation of beta- and gamma-tocopherol pair demonstrating, respectively, para- and ortho- arrangement of methyl substituents on the 6-chromanol ring, has been elucidated. It was pointed out that selectivity of each stationary phase has been a result of modulation in the mass transfer and set of unspecific interactions in the tertiary system comprising analyte <==> stationary phase <==> mobile phase. Differences in observed retention and specific selectivity of tocopherols together with the stationary phase structure investigations indicated that a spatial organization changing of chemically bonded ligands as predominantly a solvation consequence. Additional molecular modeling studies preliminary explained some of these complicated supramolecular phenomena which caused that cholesterolic stationary phase offered beneficial performance in screening of tocopherols by HPLC and biomimetic studies of not completely recognized interactions of tocopherol isomers and biological membranes. PMID:15200386

Buszewski, Boguslaw; Krupczynska, Katarzyna; Bazylak, Grzegorz

2004-06-01

355

Novel microorganism for selective separation of coal from ash and pyrite. Fourth quarterly technical progress report, July 1, 1994--September 30, 1994  

SciTech Connect

This report summarizes the progress made during the fourth quarter of the research 9 project entitled {open_quotes}A Novel Microorganism for Selective Separation of Coal from Ash and Pyrite{close_quotes}. The objective of this project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash forming minerals. During the reporting period, the adhesion of M phlei on the surface of quartz was investigated as a function of pH and conditioning time. Results showed that the little adhesion of M phlei onto quartz occurred. The amount of M phlei adsorbed onto the surface of quartz was less compared to coal. These results suggest that it would be possible to flocculate coal selectively from ash forming minerals. Flocculation tests conducted with Illinois No. 6 coal showed that rapid flocculation takes place in the pH range of 3-4. Flocculation efficiency is highly dependent upon the M. phlei concentration.

Misra, M.; Smith, R.W.

1995-12-31

356

Diffusion and Leaching of Selected Radionuclides (Iodine129, Technetium99, and Uranium) Through Category 3 Waste Encasement Concrete and Soil Fill Material  

Microsoft Academic Search

An assessment of long-term performance of Category 3 waste-enclosing cement grouts requires data about the leachability\\/diffusion of radionuclide species (iodine-129, technetium-99, and uranium) when the waste forms come in contact with groundwater. Leachability data were collected by conducting dynamic (ANS-16.1) and static leach tests on radionuclide-containing cement specimens. The diffusivity of radionuclides in soil and concrete media was collected by

Shas V. Mattigod; Greg A. Whyatt; R. Jeffrey Serne; Kristen E Schwab; Marcus I. Wood

2001-01-01

357

Extraction of uranium(VI) by N,N-di-(2-ethylhexyl)isobutyramide (DEHIBA): from the batch experimental data to the countercurrent process  

SciTech Connect

The selective separation of uranium(VI) in the first cycle of the GANEX process is operated by a hydrometallurgical process using a monoamide extractant DEHiBA (N,N-di-(2-ethylhexyl)isobutyramide). Distribution ratios of uranium(VI) and nitric acid in 1 M DEHiBA/HTP were determined with macro-concentrations of uranium, and the experimental data were modelled by taking into account the activity coefficients of the constituents in aqueous phases. A flowsheet was designed and tested in a countercurrent process in laboratory-scale mixer-settlers on a surrogate U(VI)/HNO 3 feed. More than 99.999% of the uranium was recovered. (authors)

Miguirditchian, M.; Sorel, C.; Cames, B.; Bisel, I.; Baron, P. [CEA Valrho, DEN/DRCP/SCPS, BP 17171, Bagnols-sur-Ceze, 30207 (France)

2008-07-01

358

Meniscus membranes for separations  

DOEpatents

Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

Dye, Robert C. (Irvine, CA); Jorgensen, Betty (Jemez Springs, NM); Pesiri, David R. (Aliso Viejo, CA)

2004-01-27

359

Meniscus Membranes For Separation  

DOEpatents

Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

Dye, Robert C. (Irvine, CA); Jorgensen, Betty (Jemez Springs, NM); Pesiri, David R. (Aliso Viejo, CA)

2005-09-20

360

Selective Separation and Extraction of Vanadium (V) Over Manganese (II) from Co-Leaching Solution of Roasted Stone Coal and Pyrolusite Using Solvent Extraction  

NASA Astrophysics Data System (ADS)

Based on the novel technology for selective separation and extraction of vanadium (V) over manganese (II) from co-leaching solution of roasted stone coal and pyrolusite using solvent extraction, the extraction effect of vanadium (V) and manganese (II) has been studied and many technical conditions have also been optimized. Meanwhile, countercurrent simulation experiments were conducted to verify the results of the experiments. The results indicated that with three countercurrent extraction stages, 99.21% vanadium (V) was extracted using 5% (v/v) N235 and 5% (v/v) secondary octyl alcohol at initial aqueous pH of 3.0 and O/A phase ratio of 1.0. Vanadium (V) could be completely stripped after three-stage countercurrent experiments with 20 wt.% NH4Cl at O/A phase ratio of 1.0. The process flow sheet for the recovery of vanadium (V), as well as manganese (II), was proposed.

Cai, Z. L.; Feng, Y. L.; Zhou, Y. Z.; Li, H. R.; Wang, W. D.

2013-11-01

361

Establishment of a search library about benzylisoquinoline alkaloids based on selective separation on the binaphthyl column and standard analysis on C18 column.  

PubMed

A search library about benzylisoquinoline alkaloids was established based on preparation of alkaloid fractions from Rhizoma coptidis, Cortex phellodendri, and Rhizoma corydalis. In this work, two alkaloid fractions from each herbal medicine were first prepared based on selective separation on the "click" binaphthyl column. And then these alkaloid fractions were analyzed on C18 column by liquid chromatography coupled with tandem mass spectrometry. Many structure-related compounds were included in these alkaloids fractions, which led to easy separation and good MS response in further work. Therefore, a search library of 52 benzylisoquinoline alkaloids was established, which included eight aporphine, 19 tetrahydroprotoberberine, two protopine, two benzyltetrahydroisoquinoline, and 21 protoberberine alkaloids. The information of the search library contained compound names, structures, retention times, accurate masses, fragmentation pathways of benzylisoquionline alkaloids, and their sources from three herbal medicines. Using such a library, the alkaloids, especially those trace and unknown components in some herbal medicine could be accurately and quickly identified. In addition, the distribution of benzylisoquinoline alkaloids in the herbal medicines could be also summarized by searching the source samples in the library. PMID:23109405

Liu, Qiaoxia; Zhou, Binbin; Wang, Xinliang; Ke, Yanxiong; Jin, Yu; Yin, Lihui; Liang, Xinmiao

2012-12-01

362

Uranium Industry Annual, 1992  

SciTech Connect

The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

Not Available

1993-10-28

363

Process for the production of ceramic plutonium-uranium nuclear fuel in the form of sintered pellets  

SciTech Connect

Ceramic plutonium-uranium fuels are made by sintering wetchemical microspheres of plutonium-uranium solid-solution oxides, carbides, nitrides, or the like, or by sintering separate plutonium- and uranium-compound microspheres mixed together, the uranium compound alternatively being in a fine-grained to pulverulent form.

Bischoff, K.; Stratton, R.W.

1980-11-04

364

Maintaining the uranium resources data system and assessing the 1989 US uranium potential resources  

Microsoft Academic Search

Under the Memorandum of Understanding (MOU) between the EIA, US Department of Energy, and the US Geological Survey (USGS), US Department of the Interior, the USGS develops estimates of uranium endowment for selected geological environments in the United States. New estimates of endowment are used to update the Uranium Resources Assessment Data (URAD) System which, beginning in 1990, is maintained

R. B. McCammon; W. I. Finch; W. D. Grundy; C. T. Pierson

1990-01-01

365

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado: Remedial action selection report. [Uranium Mill Tailings Remedial Action (UMTRA) Project  

SciTech Connect

The Gunnison uranium mill tailings site is just south of the city limits of Gunnison, Colorado, in the south-central part of the state. The entire site covers 61 acres in the valley of the Gunnison River and Tomichi Creek. Contaminated materials at the Gunnison processing site include the tailings pile, covering about 35 acres to an average depth of nine feet and containing 459,000 cubic yards. Ore storage areas and the former mill processing area cover about 20 acres on the south side of the site. The volume of contaminated materials to be disposed of as part of the remedial action is estimated to be 718,900 cubic yards. An interim action was approved by the US Department of Energy to eliminate existing safety hazards to the Gunnison community. These actions, started in September 1991, included demolition of mill buildings and related processing facilities, excavation of two underground storage tanks, removal of asbestos and other hazardous materials from buildings, storage of those materials in a secured area on the site, and improvements of site security.

Not Available

1992-10-01

366

Novel microorganism for selective separation of coal from ash and pyrite; First quarterly technical progress report, September 1, 1993--November 30, 1993  

SciTech Connect

This report summarizes the progress made during the first quarter of the research project entitled ``A Novel Microorganism for Selective Separation of Coal from Ash and Pyrite,`` DOE Grant No. DE-FG22-93PC93215. The objective of this project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash-forming minerals. During the reporting period, three different coal samples: Illinois No. 6 coal, Kentucky No. 9 coal and Pittsburgh No. 8 coal, were collected to be used in the investigation. The microorganism, M. phlei, was obtained as freeze-dried cultures and the growth characteristics of the bacteria were studied. Scanning electron microphotographs revealed that M. phlei cells are coccal in shape and are approximately 1 {mu}m in diameter. Electrokinetic measurements showed that the Illinois No. 6 and Pittsburgh No. 8 coal samples had an isoelectric point (IEP) around pH 6 whereas M. phlei had an IEP around pH 1.5. Electrokinetic measurements of the ruptured microorganisms exhibited an increase in IEP. The increase in IEP of the ruputured cells was due to the release of fatty acids and polar groups from the cell membrane.

Misra, M.; Smith, R.W.; Raichur, A.M.

1993-12-31

367

Novel microorganism for selective separation of coal from ash and pyrite. Sixth quarterly technical progress report, January 1, 1995--March 31, 1995  

SciTech Connect

The objective of this research project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash forming minerals. During the reporting period, the flocculation efficiencies of Illinois No. 6 and KY No. 9 coal in the presence of whole and ruptured cells of M. phlei were studied. The effect of synthetic flocculants were also studied for comparison at selected pH values. Results showed that the whole cells of M. phlei can flocculate coal very effectively and rapidly for both the coal samples. However, with ruptured cells of M. phlei the flocculation efficiency is significantly less which can be attributed to the loss of extracellular surfactants during rupturing. Separation of flocs using column flotation was studied for both the coal samples in the acidic pH range. Results indicated that excellent rejection of pyritic sulfur and ash could be obtained with a high combustible recovery. DLVO calculations were performed for all the minerals used in this study to calculate the interaction energies in the presence of whole cells and ruptured cells of M. phlei. A minimum in interaction energy is observed between coal and whole cells of M. phlei at pH 4 which is probably responsible for the higher adhesion and flocculation efficiencies at the pH. However, with ruptured cells the interaction energy increases thus decreasing the amount of M. phlei cells adhering to the surface.

Misra, M.; Smith, R.W.; Raichur, A.M.

1995-08-01

368

Homogeneous liquid-liquid extraction of uranium(VI) using tri-n-octylphosphine oxide.  

PubMed

A simple and efficient method for the selective separation and preconcentration of uranium(VI) using homogeneous liquid-liquid extraction was developed. Tri-n-octylphosphine oxide (TOPO) and tri-n-butylphosphate (TBP) were investigated as complexing ligands, and perfluorooctanoate ion (PFOA-) was applied as a phase separator agent under strongly acidic conditions. Under the optimal conditions ([PFOA-] = 1.7 x 10(-3) M, [TOPO] = 5.4 x 10(-4) M, [HNO3] = 0.3 M, [acetone] = 3.2% v/v) 10 microg of uranium in 40 ml aqueous phase could be extracted quantitatively into 8 microl of the sedimented phase. The maximum concentration factor was 5000-fold. However, an effort for the quantitative extraction using TBP was inefficient and the percent recovery was at most 56.7. The influence of the type and concentration of acid solution, optimum amount of the ligand, type and volume of the organic solvent, concentration of PFOA, volume of the aqueous sample and effect of different diverse ions on the extraction and determination of uranium(VI) were investigated. The proposed method was applied to the extraction and determination of uranium(VI) in natural water samples. PMID:15228110

Ghiasvand, Ali Reza; Mohagheghzadeh, Elham

2004-06-01

369

Bioremediation of uranium contaminated soils and wastes  

SciTech Connect

Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (1) stabilization of uranium and toxic metals with reduction in waste volume and (2) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.

Francis, A.J.

1998-12-31

370

Actinide(III)\\/lanthanide(III) Separation Via Selective Aqueous Complexation of Actinides(III) Using a Hydrophilic 2,6Bis(1,2,4-Triazin-3-Yl)Pyridine in Nitric Acid  

Microsoft Academic Search

i-SANEX is a process for separating actinides(III) from used nuclear fuels by solvent extraction: Actinides(III) and lanthanides(III) are co-extracted from a PUREX raffinate followed by selective back extraction of actinides(III) from the loaded organic phase. This step requires a complexing agent selective for actinides(III). A hydrophilic sulfonated bis triazinyl pyridine (SO3-Ph-BTP) was synthesised and tested for selective complexation of actinides(III)

Andreas Geist; Udo Müllich; Daniel Magnusson; Peter Kaden; Giuseppe Modolo; Andreas Wilden; Thomas Zevaco

2012-01-01

371

Plutonium recovery from spent reactor fuel by uranium displacement  

DOEpatents

A process for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

Ackerman, John P. (Downers Grove, IL)

1992-01-01

372

Plutonium recovery from spent reactor fuel by uranium displacement  

DOEpatents

A process is described for separating uranium values and transuranic values from fission products containing rare earth values when the values are contained together in a molten chloride salt electrolyte. A molten chloride salt electrolyte with a first ratio of plutonium chloride to uranium chloride is contacted with both a solid cathode and an anode having values of uranium and fission products including plutonium. A voltage is applied across the anode and cathode electrolytically to transfer uranium and plutonium from the anode to the electrolyte while uranium values in the electrolyte electrolytically deposit as uranium metal on the solid cathode in an amount equal to the uranium and plutonium transferred from the anode causing the electrolyte to have a second ratio of plutonium chloride to uranium chloride. Then the solid cathode with the uranium metal deposited thereon is removed and molten cadmium having uranium dissolved therein is brought into contact with the electrolyte resulting in chemical transfer of plutonium values from the electrolyte to the molten cadmium and transfer of uranium values from the molten cadmium to the electrolyte until the first ratio of plutonium chloride to uranium chloride is reestablished.

Ackerman, J.P.

1992-03-17

373

Advanced reactor design study. Assessing nonbackfittable concepts for improving uranium utilization in light water reactors  

SciTech Connect

The objective of the Advanced Reactor Design Study (ARDS) is to identify and evaluate nonbackfittable concepts for improving uranium utilization in light water reactors (LWRs). The results of this study provide a basis for selecting and demonstrating specific nonbackfittable concepts that have good potential for implementation. Lead responsibility for managing the study was assigned to the Pacific Northwest Laboratory (PNL). Nonbackfittable concepts for improving uranium utilization in LWRs on the once-through fuel cycle were selected separately for PWRs and BWRs due to basic differences in the way specific concepts apply to those plants. Nonbackfittable concepts are those that are too costly to incorporate in existing plants, and thus, could only be economically incorporated in new reactor designs or plants in very early stages of construction. Essential results of the Advanced Reactor Design Study are summarized.

Fleischman, R.M.; Goldsmith, S.; Newman, D.F.; Trapp, T.J.; Spinrad, B.I.

1981-09-01

374

Electromagnetic separation of actinide isotopes  

NASA Astrophysics Data System (ADS)

This report describes the design and technical characteristics of the electromagnetic mass-separator S-2 VNIIEF employed in the production of highly enriched isotopes of heavy actinide elements with a small relative difference of mass numbers. The mass-separator S-2 provides highly enriched isotopes in amounts adequate for nuclear physics and applied investigations. The technological procedure is presented, as well as the operational results over many years in the production of highly enriched isotopes of uranium, plutonium, americium and curium.

Abramychev, S. M.; Balashov, N. V.; Vesnovskii, S. P.; Vjachin, V. N.; Lapin, V. G.; Nikitin, E. A.; Polynov, V. N.

1992-08-01

375

Laser separation of medical isotopes  

Microsoft Academic Search

There is an increasing demand for different separated isotopes as feed material for reactor and cyclotron-produced radioisotopes used by a fast-growing radiopharmaceutical industry. One new technology that may meet future demands for medical isotopes is molecular laser isotope separation (MLIS). This method was investigated for the enrichment of uranium in the 1970`s and 1980s by Los Alamos National Laboratory, Isotope

J. W. Eerkens; D. A. Puglishi; W. H. Miller

1996-01-01

376

Photochemistry of uranium compounds  

SciTech Connect

This paper reviews the unclassified progress on the photochemistry of the following uranium compounds: UF/sub 6/, othe uranium halides, classical coordination complexes, uranium alkoxides, organometallic compounds, and uranium borohydride. Uranyl compounds are mentioned briefly. Recommendations for future studies are given. 61 references. (DLC)

Paine, R.T.; Kite, M.S.

1980-01-01

377

Uranium Industry Annual 1999.  

National Technical Information Service (NTIS)

The Uranium Industry Annual 1999 (UIA 1999) provides current statistical data on the U.S. uranium industry's activities relating to uranium raw materials and uranium marketing. The UIA 1999 is prepared for use by the Congress, Federal and State agencies, ...

2000-01-01

378

Method for fabricating laminated uranium composites  

DOEpatents

The present invention is directed to a process for fabricating laminated composites of uranium or uranium alloys and at least one other metal or alloy. The laminated composites are fabricated by forming a casting of the molten uranium with the other metal or alloy which is selectively positioned in the casting and then hot-rolling the casting into a laminated plate in or around which the casting components are metallurgically bonded to one another to form the composite. The process of the present invention provides strong metallurgical bonds between the laminate components primarily since the bond disrupting surface oxides on the uranium or uranium alloy float to the surface of the casting to effectively remove the oxides from the bonding surfaces of the components.

Chapman, L.R.

1983-08-03

379

Determination of uranium and impurities in Portuguese yellow-cakes.  

PubMed

A method is described for separation of impurities in uranium yellow cakes from Urgeiriça (Portugal). The trace metals are separated and concentrated by solvent extraction from 6M nitric acid into 100% TBP. The raffinate is then analysed directly by flame spectrometry. Uranium is determined gravimetrically after stripping of the organic phase. The method is fast and economic, and the results are in good agreement with those obtained by specific methods for each element after prior separation of uranium by precipitation or solvent extraction with various solvents. PMID:18962094

de Jesus Tavares, M; E Barros, J S; Matos, F

1977-05-01

380

Particle separation  

NASA Technical Reports Server (NTRS)

Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)

2011-01-01

381

Evaluation of the analysis of plutonium materials for low-level uranium using a modified Scintrex uranium analyzer (laser fluorometer)  

NASA Astrophysics Data System (ADS)

Evaluation and analysis of low-level uranium in plutonium materials using a modified Scintrex UA-3 Uranium Analyzer are described. Two liquid/liquid procedures for the separation of uranium from plutonium are compared. They are 0.1M tri-n-octylphosphine oxide (TOPO) in cyclohexane and 20% (v/v) tributyl phosphate (TBP) in 2,2,4-trimethylpentane (iso-octane).

Michel, C. E.; Weiss, J. R.

1985-09-01

382

Etude de la complexation selective de l'uranium (IV) et du plutonium (IV) par l'heteropolyanion P(sub 2)W(sub 17)O(sub 16)(sup 10-). (Study of selective complexation of uranium (IV) and plutonium (IV) by heteropolyanion P(sub 2)W(sub 17)O(sub 16)(sup 10-)).  

National Technical Information Service (NTIS)

The stabilization of uranium (IV) in presence of plutonium is an important direction of research in the Purex process spent fuel reprocessing. A way analysed is the formation of a complexe with the heteropolyanion ligand (P(sub 2) W(sub 17) O(sub 16)(sup ...

L. Bion P. Moisy P. Blanc C. Madic

1994-01-01

383

Innovative Separations Technologies  

SciTech Connect

Reprocessing used nuclear fuel (UNF) is a multi-faceted problem involving chemistry, material properties, and engineering. Technology options are available to meet a variety of processing goals. A decision about which reprocessing method is best depends significantly on the process attributes considered to be a priority. New methods of reprocessing that could provide advantages over the aqueous Plutonium Uranium Reduction Extraction (PUREX) and Uranium Extraction + (UREX+) processes, electrochemical, and other approaches are under investigation in the Fuel Cycle Research and Development (FCR&D) Separations Campaign. In an attempt to develop a revolutionary approach to UNF recycle that may have more favorable characteristics than existing technologies, five innovative separations projects have been initiated. These include: (1) Nitrogen Trifluoride for UNF Processing; (2) Reactive Fluoride Gas (SF6) for UNF Processing; (3) Dry Head-end Nitration Processing; (4) Chlorination Processing of UNF; and (5) Enhanced Oxidation/Chlorination Processing of UNF. This report provides a description of the proposed processes, explores how they fit into the Modified Open Cycle (MOC) and Full Recycle (FR) fuel cycles, and identifies performance differences when compared to 'reference' advanced aqueous and fluoride volatility separations cases. To be able to highlight the key changes to the reference case, general background on advanced aqueous solvent extraction, advanced oxidative processes (e.g., volumetric oxidation, or 'voloxidation,' which is high temperature reaction of oxide UNF with oxygen, or modified using other oxidizing and reducing gases), and fluorination and chlorination processes is provided.

J. Tripp; N. Soelberg; R. Wigeland

2011-05-01

384

Separation and preconcentration of chromium species by selective absorption on Lemna minor and determination by slurry atomisation electrothermal atomic absorption spectrometry.  

PubMed

A novel method for the separation and preconcentration of Cr(III)/Cr(VI) with Lemna minor and determination by slurry atomization electrothermal atomic absorption spectrometry (ETAAS) was developed. A sample solution was added to a polyethylene beaker containing 10 mg of 160 mesh pre-treated Lemna minor, adjusted to pH 1.0, stirred for 8 min for selective absorption of Cr(III) and then centrifuged. The upper layer of solution was transferred into another polyethylene beaker containing 10 mg of 160 mesh pre-treated Lemna minor, adjusted to pH 5.0, stirred for 12 min for adsorption of the residual Cr(VI) and centrifuged. The two residues in two centrifuge tubes were washed twice with water, 2 ml of agar solution added, stirred for 2 min, then two slurries were prepared and used for the determination of Cr(III) and Cr(VI) by ETAAS. Detection limits (3sigma) of 0.01 microg L(-1) for Cr(III) and 0.03 microg L(-1) for Cr(VI) were obtained. The relative standard deviation was 2.8% for Cr(III) and 3.3% for Cr(VI) at the 1 microg L(-1) level. The method was applied to the determination of Cr(III)/Cr(VI) in water samples. The analytical recoveries of Cr(III) and Cr(VI) added to samples were 97-102 and 96-103%, respectively. PMID:11534625

Zhu, G; Li, S

2001-08-01

385

Pyridinylboronic acid-functionalized organic-silica hybrid monolithic capillary for the selective enrichment and separation of cis-diol-containing biomolecules at acidic pH.  

PubMed

Boronate affinity chromatography (BAC) is a unique means for the selective separation and enrichment of 1,2 and 1,3 cis-diol-containing compounds. However, conventional boronate affinity materials require a basic binding pH (usually?8.5), which gives rise to not only inconvenience in operation but also the risk of degradation of labile compounds. Although the applicable pH has been expanded to 5.0 in recent years, the current boronate affinity materials still fail to meet the acidic pH end of frequently used biosamples, particularly urine (pH 4.5). In this study, we report a 3-pyridylboronic acid-functionalized organic-silica hybrid monolithic capillary that exhibited a binding pH of 4.5, the lowest so far in BAC. Such a binding pH enabled direct extraction of cis-diol-containing biomolecules such as nucleosides from urine samples without pH adjustment. The boronate affinity monolithic capillary showed enhanced affinity toward negatively charged cis-diol-containing analytes such as ribonucleotides. Moreover, it could function as an anion exchanger at acidic pH (?2). The column was found to retain multiple compounds from urine, which can be assumed to be at least mostly if not entirely cis-diol-containing compounds. PMID:24671037

Li, Daojin; Li, Qianjin; Wang, Shuangshou; Ye, Jin; Nie, Hongyuan; Liu, Zhen

2014-04-25

386

Whole-rock uranium analysis by fission track activation  

NASA Technical Reports Server (NTRS)

We report a whole-rock uranium method in which the polished sample and track detector are separated in a vacuum chamber. Irradiation with thermal neutrons induces uranium fission in the sample, and the detector records the integrated fission track density. Detection efficiency and geometric factors are calculated and compared with calibration experiments.

Weiss, J. R.; Haines, E. L.

1974-01-01

387

Process for recovering niobium from uranium-niobium alloys  

DOEpatents

Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and leave an insoluble residue of niobium stannide, then separating the niobium stannide from the acid.

Wallace, Steven A. (Knoxville, TN); Creech, Edward T. (Oak Ridge, TN); Northcutt, Walter G. (Oak Ridge, TN)

1983-01-01

388

Process for recovering niobium from uranium-niobium alloys  

DOEpatents

Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and form a precipitate of niobium stannide, then separating the precipitate from the acid.

Wallace, S.A.; Creech, E.T.; Northcutt, W.G.

1982-09-27

389

Uranium industry annual 1994  

SciTech Connect

The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data collected on the ``Uranium Industry Annual Survey`` (UIAS) provide a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ``Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,`` is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2.

NONE

1995-07-05

390

Laboratory simulation studies of uranium mobility in natural waters  

NASA Astrophysics Data System (ADS)

The effects of imposed variations of pH and Eh on aqueous uranium mobility at 25°C have been studied in three simulations of natural water systems. Constituents tested for their effect on uranium mobility were: (a) hydrous ferric oxide, to represent adsorptive solids which precipitate or dissolve in response to variations in pH and Eh. (b) kaolinite, representing minerals which, although modified by pH and Eh changes, are present as solids over the pH-Eh range of natural waters. (c) carbonate, to represent a strong uranium-complexing species. Uranium mobility measurements from each simulation were regressed against pH and Eh within a range appropriate to natural waters. Hydrous ferric oxide and kaolinite each affected uranium mobility, but in separate pH-Eh domains. Aqueous carbonate increased mobility of uranium, and adsorption of UO 2(CO 3) 34- caused colloidal dispersion of hydrous ferric oxide, possibly explaining the presence of 'hydrothermal hematite' in some uranium deposits. Enhanced uranium mobility observed in the pH-Eh domains of thermodynamically insoluble uranium oxides could be explained if the oxides were present as colloids. Uranium persisting as a mobile species, even after reduction, has implications for the near surface genesis of uranium ores.

Giblin, A. M.; Batts, B. D.; Swaine, D. J.

1981-05-01

391

DISPOSAL OF RADIOACTIVE WASTE IN THE VITRO-TYPE URANIUM MILLING FLOWSHEET  

Microsoft Academic Search

Pollution from radioactive nuclides, principally Ra²²⁶, in liquid ; waste from uranium mills can be minimized by reusing the waste solution within ; the mill. Such reuse of waste solution in an acid leaching process for ; dissolution of the uranium, countercurrent decantation for liquid-solid ; separation and washing, and amine solvent extraction for recovery of the uranium ; from

K. E. Tame; E. G. Valdez; J. B. Rosenbaum

1961-01-01

392

Enriched uranium recovery flowsheet improvements  

SciTech Connect

Savannah River uses 7.5% TBP to recover and purify enriched uranium. Adequate decontamination from fission products is necessary to reduce personnel exposure and to ensure that the enriched uranium product meets specifications. Initial decontamination of the enriched uranium from the fission products is carried out in the 1A bank, 16 stages of mixer-settlers. Separation of the enriched uranium from the fission product, /sup 95/Zr, has been adequate, but excessive solvent degradation caused by the long phase contact times in the mixer-settlers has limited the /sup 95/Zr decontamination factor (DF). An experimental program is investigating the replacement of the current 1A bank with either centrifugal contactors or a combination of centrifugal contactors and mixer-settlers. Experimental work completed has compared laboratory-scale centrifugal contactors and mixer-settlers for /sup 95/Zr removal efficiencies. Feed solutions spiked with actual plant solutions were used. The /sup 95/Zr DF was significantly better in the mixer-settlers than in the centrifugal contactors. As a result of this experimental study, a hybrid equipment flowsheet has been proposed for plant use. The hybrid equipment flowsheet combines the advantages of both types of solvent extraction equipment. Centrifugal contactors would be utilized in the extraction and initial scrub sections, followed by additional scrub stages of mixer-settlers.

Holt, D L

1986-01-01

393

Magnetic separation for soil decontamination  

SciTech Connect

High gradient magnetic separation (HGMS) is a physical separation process that is used to extract magnetic particles from mixtures. The technology is used on a large scale in the kaolin clay industry to whiten or brighten kaolin clay and increase its value. Because all uranium and plutonium compounds are slightly magnetic, HGMS can be used to separate these contaminants from non-magnetic soils. A Cooperative Research and Development Agreement (CRADA) was signed in 1992 between Los Alamos National Laboratory (LANL) and Lockheed Environmental Systems and Technologies Company (LESAT) to develop HGMS for soil decontamination. This paper reports progress and describes the HGMS technology.

Avens, L.R.; Worl, L.A.; deAguero, K.J.; Padilla, D.D.; Prenger, F.C.; Stewart, W.F.; Hill, D.D. [Los Alamos National Lab., NM (United States); Tolt, T.L. [Lockheed Environmental Systems and Technologies (United States)

1993-02-01

394

Magnetic separation for soil decontamination  

SciTech Connect

High gradient magnetic separation (HGMS) is a physical separation process that is used to extract magnetic particles from mixtures. The technology is used on a large scale in the kaolin clay industry to whiten or brighten kaolin clay and increase its value. Because all uranium and plutonium compounds are slightly magnetic, HGMS can be used to separate these contaminants from non-magnetic soils. A Cooperative Research and Development Agreement (CRADA) was signed in 1992 between Los Alamos National Laboratory (LANL) and Lockheed Environmental Systems and Technologies Company (LESAT) to develop HGMS for soil decontamination. This paper reports progress and describes the HGMS technology.

Avens, L.R.; Worl, L.A.; deAguero, K.J.; Padilla, D.D.; Prenger, F.C.; Stewart, W.F.; Hill, D.D. (Los Alamos National Lab., NM (United States)); Tolt, T.L. (Lockheed Environmental Systems and Technologies (United States))

1993-01-01

395

Isotope Separation System.  

National Technical Information Service (NTIS)

This invention relates to the separation of isotopes and in particular to a magnetic separation system for ions selectively ionized by laser radiation. In this invention for the enrichment of exp 235 U isotopes the magnetic field is applied with a force w...

H. K. Forsen

1976-01-01

396

Logistics of Australian Uranium in the World Market.  

National Technical Information Service (NTIS)

The labor union and physical obstacles to shipping Australian uranium to the marketplace are mentioned. Cost of the logistical system comprises five separate components: equipment cost, insurance cost, freight and security cost, interest cost, freight and...

D. Harmon

1982-01-01

397

New Technologies for the Treatment of Uranium Ores.  

National Technical Information Service (NTIS)

The new technologies on hydrometallurgy which are described concern operating conditions of acid leaching, solid liquid separation after leaching, and solvents recuperation of uranium. The acid leaching of the pulp obtained from wet crushing uses sulfuric...

J. Renaud G. Boutonnet

1977-01-01

398

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Gunnison, Colorado: Remedial action selection report. Final report  

SciTech Connect

The Gunnison uranium mill tailings site is just south of the city limits of Gunnison, Colorado, in the south-central part of the state. The entire site covers 61 acres in the valley of the Gunnison River and Tomichi Creek. Contaminated materials at the Gunnison processing site include the tailings pile, covering about 35 acres to an average depth of nine feet and containing 459,000 cubic yards. Ore storage areas and the former mill processing area cover about 20 acres on the south side of the site. The volume of contaminated materials to be disposed of as part of the remedial action is estimated to be 718,900 cubic yards. An interim action was approved by the US Department of Energy to eliminate existing safety hazards to the Gunnison community. These actions, started in September 1991, included demolition of mill buildings and related processing facilities, excavation of two underground storage tanks, removal of asbestos and other hazardous materials from buildings, storage of those materials in a secured area on the site, and improvements of site security.

Not Available

1992-10-01

399

The UVJ Selection of Quiescent and Star-forming Galaxies: Separating Early- and Late-type Galaxies and Isolating Edge-on Spirals  

NASA Astrophysics Data System (ADS)

We utilize for the first time Hubble Space Telescope Advanced Camera for Surveys imaging to examine the structural properties of galaxies in the rest-frame U - V versus V - J diagram (i.e., the UVJ diagram) using a sample at 0.6 < z < 0.9 that reaches a low stellar mass limit (log M/M ? >10.25). The use of the UVJ diagram as a tool to distinguish quiescent galaxies from star-forming galaxies (SFGs) is becoming more common due to its ability to separate red quiescent galaxies from reddened SFGs. Quiescent galaxies occupy a small and distinct region of UVJ color space and we find most of them to have concentrated profiles with high Sérsic indices (n > 2.5) and smooth structure characteristic of early-type systems. SFGs populate a broad but well-defined sequence of UVJ colors and are comprised of objects with a mix of Sérsic indices. Interestingly, most UVJ-selected SFGs with high Sérsic indices also display structure due to dust and star formation typical of the n < 2.5 SFGs and late-type systems. Finally, we find that the position of an SFG on the sequence of UVJ colors is determined to a large degree by the mass of the galaxy and its inclination. Systems that are closer to edge-on generally display redder colors and lower [O II]?3727 luminosity per unit mass as a consequence of the reddening due to dust within the disks. We conclude that the two main features seen in UVJ color space correspond closely to the traditional morphological classes of early- and late-type galaxies. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

Patel, Shannon G.; Holden, Bradford P.; Kelson, Daniel D.; Franx, Marijn; van der Wel, Arjen; Illingworth, Garth D.

2012-04-01

400

Determination of rare-earth elements in uranium-bearing materials by inductively coupled plasma mass spectrometry.  

PubMed

A novel and simple analytical procedure has been developed for the trace-level determination of lanthanides (rare-earth elements) in uranium-bearing materials by inductively coupled plasma sector-field mass spectrometry (ICP-SFMS). The method involves a selective extraction chromatographic separation of lanthanides using TRU resin followed by ICP-SFMS analysis. The limits of detection of the method proposed is in the low pg g(-1) range, which are approximately two orders of magnitude better than that of without chemical separation. The method was validated by the measurement of reference material and applied for the analysis of uranium ore concentrates (yellow cakes) for nuclear forensic purposes, as a potential application of the methodology. PMID:20152406

Varga, Zsolt; Katona, Róbert; Stefánka, Zsolt; Wallenius, Maria; Mayer, Klaus; Nicholl, Adrian

2010-03-15

401

230Th-234U Age-Dating Uranium by Mass Spectrometry  

Microsoft Academic Search

This is the standard operating procedure used by the Isotope Ratio Mass Spectrometry Group of the Chemical Sciences Division at LLNL for the preparation of a sample of uranium oxide or uranium metal for ²³°Th-²³⁴U age-dating. The method described here includes the dissolution of a sample of uranium oxide or uranium metal, preparation of a secondary dilution, spiking of separate

R W Williams; A M Gaffney

2012-01-01

402

Evolution of isotopic composition of reprocessed uranium during the multiple recycling in light water reactors with natural uranium feed  

SciTech Connect

A complex approach based on the consistent modeling of neutron-physics processes and processes of cascade separation of isotopes is applied for analyzing physical problems of the multiple usage of reprocessed uranium in the fuel cycle of light water reactors. A number of scenarios of multiple recycling of reprocessed uranium in light water reactors are considered. In the process, an excess absorption of neutrons by the {sup 236}U isotope is compensated by re-enrichment in the {sup 235}U isotope. Specific consumptions of natural uranium for re-enrichment of the reprocessed uranium depending on the content of the {sup 232}U isotope are obtained.

Smirnov, A. Yu., E-mail: a.y.smirnoff@rambler.ru; Sulaberidze, G. A. [National Research Nuclear University MEPhI (Russian Federation); Alekseev, P. N.; Dudnikov, A. A.; Nevinitsa, V. A., E-mail: neva@dhtp.kiae.ru; Proselkov, V. N.; Chibinyaev, A. V. [Russian Research Centre Kurchatov Institute (Russian Federation)

2012-12-15

403

Bicarbonate leaching of uranium  

SciTech Connect

The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

Mason, C.

1998-12-31

404

The Navajo Uranium Mining Experience, 2003-1952  

NSDL National Science Digital Library

This bibliography, compiled by the Southwest Research and Information Center, contains resources related to Navajo uranium issues and communities affected by uranium mining impacts since the mid-1970s. Entries were selected for their relevancy to Navajo community concerns, Navajo Nation policies, and health and environmental effects of uranium development on Navajo lands. Topics for resources include articles, books, policy statements, reports, presentations, testimony, and published medical, scientific and sociological literature.

Shuey, Chris; Center, Southwest R.

405

Uranium hexafluoride bibliography  

SciTech Connect

This bibliography is a compilation of reports written about the transportation, handling, safety, and processing of uranium hexafluoride. An on-line literature search was executed using the DOE Energy files and the Nuclear Science Abstracts file to identify pertinent reports. The DOE Energy files contain unclassified information that is processed at the Office of Scientific and Technical Information of the US Department of Energy. The reports selected from these files were published between 1974 and 1983. Nuclear Science Abstracts contains unclassified international nuclear science and technology literature published from 1948 to 1976. In addition, scientific and technical reports published by the US Atomic Energy Commission and the US Energy Research and Development Administration, as well as those published by other agencies, universities, and industrial and research organizations, are included in the Nuclear Science Abstracts file. An alphabetical listing of the acronyms used to denote the corporate sponsors follows the bibliography.

Burnham, S.L.

1988-01-01

406

Uranium in Dental Porcelain.  

National Technical Information Service (NTIS)

The radiological health aspects of the use of uranium in dental porcelain are presented. The concentration of uranium is reported for 18 sets of porcelain teeth and 23 samples of porcelain powder. Particle emission rates were obtained for uranium and for ...

D. L. Thompson

1976-01-01

407

PROPERTIES OF URANIUM CARBIDES  

Microsoft Academic Search

Properties of uranium carbides are reviewed and brought up to date. ; Photographs and photomicrographs of uranium carbides fabricated by melting and ; casting techniques and by powder metallurgy techniques are presented. Recent ; data confirm that uranium monocarbide has metallic conductivity (a thermal ; conductivity of approximately 0.055 cal\\/sec-cm- deg C and a resistivity of ; approximately 35 microhm-cm)

W. Chubb; R. F. Dickerson

1962-01-01

408

Remedial Action Plan and Site Design for Stabilization of the Inactive Uranium Mill Tailings Site, Maybell, Colorado. Remedial action selection report: Attachment 2, Geology report, Final  

SciTech Connect

The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers [km]) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The designated site covers approximately 110 acres (ac) (45 hectares [ha]) and consists of a concave-shaped tailings pile and rubble from the demolition of the mill buildings buried in the former mill area. Contaminated materials at the Maybell processing site include the tailings pile, which has an average depth of 20 feet (ft) (6 meters [m]) and contains 2.8 million cubic yards (yd{sup 3}) (2.1 million cubic meters [m{sup 3}]) of tailings. The former mill processing area is on the north side of the site and contains 20,000 yd{sup 3} (15,000 m{sup 3}) of contaminated demolition debris. Off-pile contamination is present and includes areas adjacent to the tailings pile, as well as contamination dispersed by wind and surface water flow. The volume of off-pile contamination to be placed in the disposal cell is 550,000 yd{sup 3} (420,000 m{sup 3}). The total volume of contaminated materials to be disposed of as part of the remedial action is estimated to be 3.37 million yd{sup 3} (2.58 million m{sup 3}). Information presented in this Final Remedial Action Plan (RAP) and referenced in supporting documents represents the current disposal cell design features and ground water compliance strategy proposed by the US Department of Energy (DOE) for the Maybell, Colorado, tailings site. Both the disposal cell design and the ground water compliance strategy have changed from those proposed prior to the preliminary final RAP document as a result of prudent site-specific technical evaluations.

Not Available

1994-06-01

409

A Predictive Model for the Selective Separation of Aromatic\\/Non Aromatic Hydrocarbon Mixtures by Pervaporation Using Dense Homogenous Polymer Membranes  

Microsoft Academic Search

Separation of aromatic\\/non -aromatic mixtures by membrane based pervaportion process is usually analyzed by the solution-diffusion model which assumes that a permeating component is first dissolved in the membrane and then diffuses through the membrane due to its driving force. Therefore, the separate evaluation of sorption equilibria is necessary in order to determine the controlling step in overall mass transport

A. Ghoreyshi; G. D. Najafpour; Z. Ebrahimi

410

Process for recovery of high purity uranium from fertilizer grade weak phosphoric acid  

US Patent & Trademark Office Database

A two-cycle countercurrent extraction process for recovery of highly pure uranium from fertilizer grade weak phosphoric acid. The proposed process uses selective extraction using di-(2-ethyl hexyl) phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) with refined kerosene as synergistic extractant system on hydrogen peroxide treated phosphoric acid, and stripping the loaded extract with strong phosphoric acid containing metallic iron to lower redox potential. The loaded-stripped acid is diluted with water back to weak phosphoric acid state and its redox potential raised by adding hydrogen peroxide and re-extracted with same extractant system. This extract is first scrubbed with sulfuric acid and then stripped with alkali carbonate separating iron as a precipitate, treated with sodium hydroxide precipitating sodium uranate, which is re-dissolved in sulfuric acid and converted with hydrogen peroxide to highly pure yellow cake of uranium peroxide.

2007-03-20

411

separationsNOW.com  

NSDL National Science Digital Library

This separation science and chromatography Web portal from publisher John Wiley and Sons expects "to become the definitive separation science resource on the Internet, offering a wealth of valuable information, resources, and services." separationsNOW addresses electrophoresis, chromatography, and other separation techniques with frequently-updated news, Web links, conference announcements, technique-specific discussion forums, educational features, and much more. Free registration is required to access advanced features, such as a selection of free full-text articles in the online library.

2003-01-01

412

separationsNOW.com  

NSDL National Science Digital Library

This separation science and chromatography Web portal from publisher John Wiley and Sons expects "to become the definitive separation science resource on the Internet, offering a wealth of valuable information, resources, and services." separationsNOW addresses electrophoresis, chromatography, and other separation techniques with frequently-updated news, Web links, conference announcements, technique-specific discussion forums, educational features, and much more. Free registration is required to access advanced features, such as a selection of free full-text articles in the online library.

2005-12-05

413

ELECTROCHEMICALLY MODULATED SEPARATIONS FOR MATERIAL ACCOUNTABILITY MEASUREMENTS  

SciTech Connect

A method for the accurate and timely analysis of accountable materials is critical for safeguards measurements in nuclear fuel reprocessing plants. Non-destructive analysis (NDA) methods, such as gamma spectroscopy, are desirable for their ability to produce near real-time data. However, the high gamma background of the actinides and fission products in spent nuclear fuel limits the use of NDA for real-time online measurements. A simple approach for at-line separation of materials would facilitate the use of at-line detection methods. A promising at-line separation method for plutonium and uranium is electrochemically modulated separations (EMS). Using an electrochemical cell with an anodized glassy carbon electrode, Pu and U oxidation states can be altered by applying an appropriate voltage. Because the affinity of the actinides for the electrode depends on their oxidation states, selective deposition can be turned “on” and “off” with changes in the applied target electrode voltage. A high surface-area cell was designed in house for the separation of Pu from spent nuclear fuel. The cell is shown to capture over 1 µg of material, increasing the likelihood for gamma spectroscopic detection of Pu extracted from dissolver solutions. The large surface area of the electrode also reduces the impact of competitive interferences from some fission products. Flow rates of up to 1 mL min?1 with >50% analyte deposition efficiency are possible, allowing for rapid separations to be effected. Results from the increased surface-area EMS cell are presented, including dilute dissolver solution simulant data.

Hazelton, Sandra G.; Liezers, Martin; Naes, Benjamin E.; Arrigo, Leah M.; Duckworth, Douglas C.

2012-07-08

414

Battery separators  

SciTech Connect

A novel, improved battery separator and process for making the separator. Essentially, the separator carries a plurality of polymeric ribs bonded to at least one surface and the ribs have alternating elevated segments of uniform maxiumum heights and depressed segments along the length of the ribs.

Le Bayon, R.; Faucon, R.; Legrix, J.

1984-11-13

415

Alumina modified by dimethyl sulfoxide as a new selective solid phase extractor for separation and preconcentration of inorganic mercury(II).  

PubMed

Dimethyl sulfoxide (DMSO) was simply immobilized to neutral alumina via quite strong hydrogen bonding between sulfoxide oxygen and surface alumina hydroxo groups. The produced alumina-modified dimethyl sulfoxide (AMDMSO) solid phase (SP)-extractor experienced high thermal and medium stability. Moreover, the small and compact size of DMSO moiety permit high surface coverage evaluated to be 2.1+/-0.1 mmol g(-1) of alumina. Hg(II) uptake was 1.90 mmol g(-1)(distribution coefficient log K(d)=5.658) at pH 1.0 or 2.0, 1.68 mmol g(-1) (log K(d)=4.067) at pH 3.0 or 4.0 while the metal ions Ca(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) showed low values 0.513-0.118 mmol g(-1) (log K(d)<3.0) in the pH range 4.0-7.0. A mechanism was suggested to explain the unique uptake of Hg(II) ions by binding as neutral and chloroanionic species predominate at pH values< or =3.0 of a medium rich in chloride ions. A direct and fast batch separation mode was achieved successfully to retain selectively Hg(II) in presence of other eight coexisting metal ions. Thus, Hg(II) was completely retained; Ca(II), Co(II), Ni(II) and Cd(II) were not retained, while Pb(II), Cu(II), Zn(II) and Fe(III) exhibited very low percentage retention evaluated to be 0.42, 0.49, 1.4 and 5.43%, respectively. The utility of the new modified alumina sorbent for concentrating of ultratrace amounts of Hg(II) was performed by percolating 2l of doubly distilled water, drinking tap water, and Nile river water spiked with 10 ng/l over 100mg of the sorbent packed in a minicolumn used as a thin layer enrichment bed prior to the determination by CV-AAS. The high recovery values obtained (98.5+/-0.5, 98.5+/-0.5 and 103.0+/-1.0) based on excellent enrichment factor 1000, along with a good precision (R.S.D.% 0.51-0.97%, N=3) demonstrate the accuracy and validity of the new modified alumina sorbent for preconcentrating ultratrace amounts of Hg(II) with no matrix interference. PMID:18970531

Soliman, Ezzat M; Saleh, Mohamed B; Ahmed, Salwa A

2006-03-15

416

High-efficiency separation of an ethylene\\/ethane mixture by a large-scale liquid-membrane contactor containing flat-sheet nonporous polymeric gas-separation membranes and a selective flowing-liquid absorbent  

Microsoft Academic Search

Ethylene and ethane were effectively separated from a mixture comprising these two gases by means of a large-scale liquid-membrane contactor (membrane permabsorber). The contactor comprised composite flat-sheet membranes with a nonporous diffusional layer made from polyblock copolymer poly(dimethylsiloxane)\\/poly(phenylsilsesquioxane) and an aqueous solution of silver nitrate flowing along turbulence-promoter spacers between the membranes. The membrane permabsorber permitted ethylene and ethane to

D. G. Bessarabov; R. D. Sanderson; E. P. Jacobs; I. N. Beckman

1995-01-01

417

Separation of Selected Bile Acids by TLC. VIII. Separation on Silica Gel 60F254 Glass Plates Impregnated with Cu(II), Ni(II), Fe(II), and Mn(II) Cations  

Microsoft Academic Search

The aim of our study was to examine the following bile acids: cholic acid (C), glycocholic acid (GC), glycolithocholic acid (GLC), deoxycholic acid (DC), chenodeoxycholic acid (CDC), glycodeoxycholic acid (GDC), and lithocholic acid (LC). In the present study, to separate a\\/m bile acids using adsorption thin layer chromatography at 18°C, the glass plates precoated with silica gel 60F254 (#1.05715), were

A. Pyka; M. Do?owy; D. Gurak

2005-01-01

418

Glutaraldehyde-crosslinked chitosan beads for sorptive separation of Au(III) and Pd(II): opening a way to design reduction-coupled selectivity-tunable sorbents for separation of precious metals.  

PubMed

Glutaraldehyde (GA)-crosslinked chitosan beads (GA-CS) are prepared with coagulating solution containing sodium tripolyphosphate and GA, and used for the adsorption of metals from binary-metal solution Au(III) and Pd(II). GA-CS exhibited selective sorption of Au(III) in the Au(III)-Pd(II) mixture. X-ray diffraction analyses showed that Au(III) was reduced to Au(0) following sorption, while Pd(II) was present as unreduced divalent form. Increased GA led to more selectivity toward Au(III), indicating that Au(III) selectivity is attributed to reduction-couple sorption of Au(III) with a reducing agent GA. Furthermore, a 2-step desorption process enabled selective recovery of Pd and Au using 5M HCl and 0.5M thiourea-1M HCl, respectively, leading to pure Pd(II) and Au(III)-enriched solutions. This finding may open a new way to design reduction-coupled selectivity-tunable metal sorbents by combination of redox potentials of metal ions and reducing agents. PMID:23376490

Park, Seong-In; Kwak, In Seob; Won, Sung Wook; Yun, Yeoung-Sang

2013-03-15

419

Characterization of streamflow, water quality, and instantaneous dissolved solids, selenium, and uranium loads in selected reaches of the Arkansas River, southeastern Colorado, 2009-2010  

USGS Publications Warehouse

As a result of continued water-quality concerns in the Arkansas River, including metal contamination from historical mining practices, potential effects associated with storage and movement of water, point- and nonpoint-source contamination, population growth, storm-water flows, and future changes in land and water use, the Arkansas River Basin Regional Resource Planning Group (RRPG) developed a strategy to address these issues. As such, a cooperative strategic approach to address the multiple water-quality concerns within selected reaches of the Arkansas River was developed to (1) identify stream reaches where stream-aquifer interactions have a pronounced effect on water quality and (or) where reactive transport, and physical and (or) chemical alteration of flow during conveyance, is occurring, (2) quantify loading from point sources, and (3) determine source areas and mass loading for selected constituents. (To see the complete abstract, open Report PDF.)

Ivahnenko, Tamara; Ortiz, Roderick F.; Stogner, Robert W., Sr.

2013-01-01

420

Evaluation of the beta energy spectrum from a distributed uranium mill tailings source  

Microsoft Academic Search

The beta energy spectra from uranium mill tailings, 90Sr with different absorber thicknesses, and a uranium metal slab were measured and compared to select an appropriate beta source for calibrating a personal dosimeter to measure shallow dose equivalent when exposed to uranium mill tailings. The measured beta energy spectrum from the 90Sr source, with a 111 mg cm-2 cover thickness,

R. H. Reif; D. E. Martz; D. S. Carlson; J. B. Turner

1993-01-01

421

Thermodynamic properties of selected uranium compounds and aqueous species at 298.15 K and 1 bar and at higher temperatures; preliminary models for the origin of coffinite deposits  

USGS Publications Warehouse

Thermodynamic values for 110 uranium-bearing phases and 28 aqueous uranium solution species (298.15 K and l bar) are tabulated based upon evaluated experimental data (largely from calorimetric experiments) and estimated values. Molar volume data are given for most of the solid phases. Thermodynamic values for 16 uranium-bearing phases are presented for higher temperatures in the form of and as a supplement to U.S. Geological Survey Bulletin 1452 (Robie et al., 1979). The internal consistency of the thermodynamic values reported herein is dependent upon the reliability of the experimental results for several uranium phases that have been used as secondary calorimetric reference phases. The data for the reference phases and for those phases evaluated with respect to the secondary reference phases are discussed. A preliminary model for coffinite formation has been proposed together with an estimate of the free energy of formation of coffinite. Free energy values are estimated for several other uranium-bearing silicate phases that have been reported as secondary uranium phases associated with uranium ore deposits and that could be expected to develop wherever uranium is leached by groundwaters.

Hemingway, B. S.

1982-01-01

422

BIOREMEDIATION OF URANIUM CONTAMINATED SOILS AND WASTES.  

SciTech Connect

Contamination of soils, water, and sediments by radionuclides and toxic metals from uranium mill tailings, nuclear fuel manufacturing and nuclear weapons production is a major concern. Studies of the mechanisms of biotransformation of uranium and toxic metals under various microbial process conditions has resulted in the development of two treatment processes: (i) stabilization of uranium and toxic metals with reduction in waste volume and (ii) removal and recovery of uranium and toxic metals from wastes and contaminated soils. Stabilization of uranium and toxic metals in wastes is accomplished by exploiting the unique metabolic capabilities of the anaerobic bacterium, Clostridium sp. The radionuclides and toxic metals are solubilized by the bacteria directly by enzymatic reductive dissolution, or indirectly due to the production of organic acid metabolites. The radionuclides and toxic metals released into solution are immobilized by enzymatic reductive precipitation, biosorption and redistribution with stable mineral phases in the waste. Non-hazardous bulk components of the waste such as Ca, Fe, K, Mg and Na released into solution are removed, thus reducing the waste volume. In the second process uranium and toxic metals are removed from wastes or contaminated soils by extracting with the complexing agent citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, followed by photochemical degradation of the uranium citrate complex which is recalcitrant to biodegradation. The toxic metals and uranium are recovered in separate fractions for recycling or for disposal. The use of combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in clean-up and disposal costs.

FRANCIS,A.J.

1998-09-17

423

Isotopic fractionation of uranium in sandstone  

USGS Publications Warehouse

Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.

Rosholt, J. N.; Shields, W. R.; Garner, E. L.

1963-01-01

424

Electrochemically-Modulated Separation and Mass Spectrometric Analysis of Actinides in Difficult Matrices  

SciTech Connect

Electrochemically-modulated separations (EMS) are a straightforward means of isolating and pre-concentrating elements for on-line mass spectrometric analysis. Elements are accumulated at electrochemical working electrodes and subsequently released into a clean carrier solution for spectroscopic analysis. EMS can employ solely aqueous chemistry and uses electrochemical redox adjustment of oxidation state to “trigger” reversible chelation / complexation. Less tractable elements (e.g., uranium and plutonium), based on redox potentials, can therefore be extracted from difficult matrices following redox adjustment and chelation with electrode chelation sites. Simply put, separation is achieved by a small voltage step that is applied to the target electrode to turn “on” or “off” the specific actinide affinity of an electrode. This separation technology employs both redox and chelation chemistry to effect highly selective accumulation of target actinides, and results in element separation, matrix elimination and analyte preconcentration. Prior studies have developed protocols and preliminary insight into EMS processes for U and Pu. U and Pu are released upon oxidation and reduction, respectively, allowing complete separation due to widely divergent redox potentials. T The coupling of EMS on-line with ICP-MS for elemental and isotopic analysis of uranium and plutonium is presented, with a focus on analytical performance metrics and applicability to safeguards and process monitoring via nondestructive analyses.

Duckworth, Douglas C.; Liezers, Martin; Lehn, Scott A.; Douglas, Matthew

2009-01-01

425

THE CONTROL OF URANIUM FIRES  

Microsoft Academic Search

Fires have occurred in the production, storing, handling and shipping of uranium powder and turnings. Batches of uranium powder, swarf and solid scrap have been ignited to observe fire temperatures and combustion rates and materials and methods to suppress or extinguish uranium fires investigated. The effect on various metals in contact with burning uranium has also been examined. The uranium

1952-01-01

426

Uranium hexafluoride public risk  

SciTech Connect

The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

1994-08-01

427

Inorganic separator technology program  

NASA Technical Reports Server (NTRS)

Testing and failure analyses of silver zinc cells with largely inorganic separators were performed. The results showed that the wet stand and cycle life objective of the silver-zinc cell development program were essentially accomplished and led to recommendations for cell composition, design, and operation that should yield further improvement in wet and cycle life. A series of advanced inorganic materials was successfully developed and formulated into rigid and semiflexible separator samples. Suitable screening tests for evaluation of largely inorganic separators were selected and modified for application to the separator materials. The results showed that many of these formulations are potentially superior to previously used materials and permitted selection of three promising materials for further evaluation in silver-zinc cells.

Smatko, J. S.; Weaver, R. D.; Kalhammer, F. R.

1973-01-01

428

Magnetic Resonance Tracking of Human CD34+ Progenitor Cells Separated by Means of Immunomagnetic Selection and Transplanted Into Injured Rat Brain  

Microsoft Academic Search

Magnetic resonance imaging (MRI) provides a noninvasive method for studying the fate of transplanted cells in vivo. We studied whether superparamagnetic nanoparticles (CD34 microbeads), used clinically for specific magnetic sorting, can be used as a magnetic cell label for in vivo cell visualization. Human cells from peripheral blood were selected by CliniMACS ? CD34 Selection Technology (Miltenyi). Purified CD34 +

Petr Kobylka; Milan Hajek; Eva Sykova

429

An equilibrium model for ligand-modified micellar-enhanced ultrafiltration, selective separation of metal ions using iminoacetic substituted polyamines and a theoretical model for the titration behavior of polyamines  

SciTech Connect

This thesis consists of three chapters. Chapter 1, An equilibrium model for ligand-modified micellar-enhanced ultrafiltration, describes a theoretical model and experimental investigations which used the semi-equilibrium-dialysis method with N-n-dodecyl iminodiacetic acid as the ligand. In Chapter 2, Selective separation of metal ions using iminoacetic substituted polyamines, polyamines with a substituted ligand group are synthesized and used in investigating selective separation of copper ions from aqueous solution. In Chapter 3, A theoretical model for the titration behavior of polyamines, a novel approach to explain the titration behavior of polymeric amines based on the binding behavior of counterions is described. The application of this study is to the investigation of inexpensive and efficient methods of industrial waste water treatment.

Dharmawardana, U.R.

1992-12-31

430

Spectrophotometric Determination of Trace Uranium in Plutonium Nitrate and Oxide with 2-(2-Pyridylazo)-5-Diethylaminophenol.  

National Technical Information Service (NTIS)

A spectrophotometric method for the determination of trace uranium in plutonium was developed and evaluated. Uranium was separated from plutonium in a 4M HCl-2M NH sub 2 OH.HCl matrix with Aliquat-336. The uranium in the organic was determined by spectrop...

W. I. Winters

1975-01-01

431

Uranium Mill Tailings Management  

SciTech Connect

This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements).

Nelson, J.D.

1982-01-01

432

Battery separators  

SciTech Connect

A description is given of a synthetic pulp separator for a lead acid battery, the separator having two or more plies and a ribbed profile the surface adapted to face the positive having a higher content of synthetic pulp than the other surface.

Clegg, G.A.; Pearson, E.J.

1981-01-13

433

Microbial transformation of uranium in wastes  

SciTech Connect

Contamination of soils, water, and sediments by radionuclides and toxic metals from the disposal of uranium processing wastes is a major national concern. Although much is known about the physico- chemical aspects of U, we have little information on the effects of aerobic and anaerobic microbial activities on the mobilization or immobilization of U and other toxic metals in mixed wastes. In order to understand the mechanisms of microbial transformations of uranium, we examined a contaminated pond sediment and a sludge sample from the uranium processing facility at Y-12 Plant, Oak Ridge, TN. The uranium concentration in the sediment and sludge samples was 923 and 3080 ug/g dry wt, respectively. In addition to U, the sediment and sludge samples contained high levels of toxic metals such as Cd, Cr, Cu, Hg, Pb, Ni, and Zn. The association of uranium with the various mineral fractions of the sediment and sludge was determined by selective chemical extraction techniques. Uranium was associated to varying degrees with the exchangeable carbonate, iron oxide, organic, and inert fractions in both samples. Initial results in samples amended with carbon and nitrogen indicate immobilization of U due to enhanced indigenous microbial activity under anaerobic conditions. 23 refs., 4 figs., 5 tabs.

Francis, A.J.; Dodge, C.J.; Gillow, J.B.; Cline, J.E. (Brookhaven National Lab., Upton, NY (USA); Oak Ridge Y-12 Plant, TN (USA))

1989-01-01

434

Selective Separation of Rare Earth Metals by Solvent Extraction in the Presence of New Hydrophilic Chelating Polymers Functionalized with Ethylenediaminetetraacetic Acid. I. Development of New Hydrophilic Chelating Polymers and Their Adsorption Properties for Rare Earth Metals  

Microsoft Academic Search

New hydrophilic chelating polymers were synthesized by introducing ethylene-diaminetetraacetic acid (EDTA) onto water-soluble polyallylamine. The selective separation of rare earth metals by solvent extraction including these chelating polymers in the aqueous phase is the goal of this work. The polymers were characterized by IR analysis, elemental analysis, gel permeation chromatography (GPC) measurement, and pH titration. Two kinds of polymers with

Hideto Matsuyama; Yoshikazu Miyamoto; Masaaki Teramoto; Masahiro Goto; Fumiyuki Nakashio

1996-01-01

435

Preparation of uranium compounds  

DOEpatents

UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

2013-02-19

436

Process for continuous production of metallic uranium and uranium alloys  

DOEpatents

A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

Hayden, Jr., Howard W. (Oakridge, TN); Horton, James A. (Livermore, CA); Elliott, Guy R. B. (Los Alamos, NM)

1995-01-01

437

Process for continuous production of metallic uranium and uranium alloys  

DOEpatents

A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

1995-06-06

438

Remedial action plan and site design for stabilization of the inactive uranium mill tailings site at Falls City, Texas. Remedial action selection report, attachment 2, geology report; attachment 3, groundwater hydrology report; and attachment 4, water resources protection strategy. Final report  

SciTech Connect

The uranium processing site near Falls City, Texas, was one of 24 inactive uranium mill sites designated to be remediated by the U.S. Department of Energy (DOE) under Title I of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). The UMTRCA requires that the U.S. Nuclear Regulatory Commission (NRC) concur with the DOE`s remedial action plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the U.S. Environmental Protection Agency (EPA). The RAP, which includes this summary remedial action selection report (RAS), serves a two-fold purpose. First, it describes the activities proposed by the DOE to accomplish long-term stabilization and control of the residual radioactive materials at the inactive uranium processing site near Falls City, Texas. Second, this document and the remainder of the RAP, upon concurrence and execution by the DOE, the State of Texas, and the NRC, becomes Appendix B of the Cooperative Agreement between the DOE and the State of Texas.

NONE

1992-09-01

439

Energy Transfer and Charge Separation in Photosystem I: P700 Oxidation Upon Selective Excitation of the Long-Wavelength Antenna Chlorophylls of Synechococcus elongatus  

Microsoft Academic Search

Photosystem I of the cyanobacterium Synechococcus elongatus contains two spectral pools of chlorophylls called C-708 and C-719 that absorb at longer wavelengths than the primary electron donor P700. We investigated the relative quantum yields of photochemical charge separation and fluorescence as a function of excitation wavelength and temperature in trimeric and monomeric photosystem I complexes of this cyanobacterium. The monomeric

Lars-Olof Pålsson; Cornelia Flemming; Bas Gobets; Rienk van Grondelle; Jan P. Dekker; Eberhard Schlodder

1998-01-01

440

Comparison of vancomycin-based stationary phases with different chiral selector coverage for enantioselective separation of selected drugs in high-performance liquid chromatography.  

PubMed

Two vancomycin-based chiral stationary phases (CSPs) with different coverage of the chiral selector vancomycin (Chirobiotic V and Chirobiotic V2) were compared. beta-Blockers and profens, as structurally diverse groups of drugs, were chosen as analytes. Retention and enantioseparation of beta-blockers were studied in reversed-phase (RP) and polar-organic (PO) separation modes. Higher retention and better enantioresolution were obtained on the CSP with higher coverage of vancomycin in the both separation modes. Baseline separation of four beta-blockers (eight enantiomers) in the PO mode was achieved on the Chirobiotic V2 column within 15 min. The enantioseparation of profens did not bring so excellent and easy to interpret results. Higher retention of profens on the Chirobiotic V2 column was not always accompanied by an improvement of their chiral separation in the RP mode. The polar-organic mode was not suitable for these derivatives at all. The most interesting result was obtained with flobufen; its chiral center is further away from the rigid part of the molecule, which mostly causes difficulties in enantioselective recognition. Nevertheless, the enantiomers of flobufen were shown to be much better (baseline) resolved on the CSP with lower coverage of the chiral selector (Chirobiotic V). PMID:16130736

Bosáková, Z; Curínová, E; Tesarová, E

2005-09-23

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