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Sample records for guide isotope separator

  1. Isotope separation

    DOEpatents

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  2. ISOTOPE SEPARATORS

    DOEpatents

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  3. Isotope separation by photochromatography

    DOEpatents

    Suslick, K.S.

    1975-10-03

    A photochromatographic method for isotope separation is described. An isotopically mixed molecular species is adsorbed on an adsorptive surface, and the adsorbed molecules are irradiated with radiation of a predetermined wavelength which will selectively excite desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thus separate them from the undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes. (BLM)

  4. Isotope separation by photochromatography

    DOEpatents

    Suslick, Kenneth S.

    1977-01-01

    An isotope separation method which comprises physically adsorbing an isotopically mixed molecular species on an adsorptive surface and irradiating the adsorbed molecules with radiation of a predetermined wavelength which will selectively excite a desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thereby separate them from the unexcited undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes.

  5. Method for separating isotopes

    DOEpatents

    Jepson, B.E.

    1975-10-21

    Isotopes are separated by contacting a feed solution containing the isotopes with a cyclic polyether wherein a complex of one isotope is formed with the cyclic polyether, the cyclic polyether complex is extracted from the feed solution, and the isotope is thereafter separated from the cyclic polyether.

  6. Laser isotope separation

    DOEpatents

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

    1975-11-26

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light is described. 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.

  7. Laser isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Boyer, Keith; Greiner, Norman R.

    1988-01-01

    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.

  8. Photochemical isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1987-01-01

    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.

  9. Separation of sulfur isotopes

    DOEpatents

    DeWitt, Robert; Jepson, Bernhart E.; Schwind, Roger A.

    1976-06-22

    Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO.sub.2) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO.sub.3). Heavier sulfur isotopes are preferentially attracted to the NaHSO.sub.3, and subsequently reacted with sulfuric acid (H.sub.2 SO.sub.4) forming sodium hydrogen sulfate (NaHSO.sub.4) and SO.sub.2 gas which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO.sub.2 gas is subsequently separated and the NaHSO.sub.4 is reacted with NaOH to form sodium sulfate (Na.sub.2 SO.sub.4) which is subsequently decomposed in an electrodialysis unit to form the NaOH and H.sub.2 SO.sub.4 components which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials.

  10. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  11. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  12. Isotope separation apparatus

    DOEpatents

    Arnush, Donald; MacKenzie, Kenneth R.; Wuerker, Ralph F.

    1980-01-01

    Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.

  13. ISOTOPE SEPARATING APPARATUS CONTROL

    DOEpatents

    Barnes, S.W.

    1959-08-25

    An improved isotope separating apparatus of the electromagnetic type, commonly referred to as a calutron, is described. Improvements in detecting and maintaining optimum position and focus of the ion beam are given. The calutron collector is provided with an additional electrode insulated from and positioned between the collecting pockets. The ion beams are properly positioned and focused until the deionizing current which flows from ground to this additional electrode ts a minimum.

  14. High Atomic Weight Isotope Separator.

    DTIC Science & Technology

    This patent discusses a method of separating one isotopic species of a given element from a mixture. Collisionless plasma instabilities slow down the ions and oppositely charged electrodes separate the isotopes.

  15. Method for separating boron isotopes

    DOEpatents

    Rockwood, Stephen D.

    1978-01-01

    A method of separating boron isotopes .sup.10 B and .sup.11 B by laser-induced selective excitation and photodissociation of BCl.sub.3 molecules containing a particular boron isotope. The photodissociation products react with an appropriate chemical scavenger and the reaction products may readily be separated from undissociated BCl.sub.3, thus effecting the desired separation of the boron isotopes.

  16. Hybrid isotope separation scheme

    DOEpatents

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus. 2 figures.

  17. Hybrid isotope separation scheme

    DOEpatents

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

  18. ISOTOPE SEPARATING APPARATUS

    DOEpatents

    Kudravetz, M.K.; Greene, H.B.

    1958-09-16

    This patent relates to control systems for a calutron and, in particular, describes an electro-mechanical system for interrupting the collection of charged particles when the ratio between the two isotopes being receivcd deviates from a predetermined value. One embodiment of the invention includes means responsive to the ratio between two isotopes being received for opening a normally closed shutter over the receiver entrance when the isotope ratio is the desired value. In another form of the invention the collection operation is interrupted by changing the beam accelerating voltage to deflect the ion beam away from the receiver.

  19. Isotope separation by laser means

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1982-06-15

    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.

  20. Hydrogen isotope separation

    DOEpatents

    Bartlit, J.R.; Denton, W.H.; Sherman, R.H.

    Disclosed is a system of four cryogenic fractional distillation columns interlinked with two equilibrators for separating a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D/sub 2/, DT, T/sub 2/, and a tritium-free stream of HD for waste disposal.

  1. Hydrogen isotope separation

    DOEpatents

    Bartlit, John R.; Denton, William H.; Sherman, Robert H.

    1982-01-01

    A system of four cryogenic fractional distillation columns interlinked with two equilibrators for separating a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D.sub.2, DT, T.sub.2, and a tritium-free stream of HD for waste disposal.

  2. Isotope separation apparatus and method

    DOEpatents

    Feldman, Barry J.

    1985-01-01

    The invention relates to an improved method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferably substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. Because the molecules in the beam occupy various degenerate energy levels, if the laser beam comprises chirped pulses comprising selected wavelengths, the laser beam will very efficiently excite substantially all unexcited molecules and will cause stimulated emission of substantially all excited molecules of a selected one of the isotopes in the beam which such pulses encounter. Excitation caused by first direction chirped pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning chirped pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement of essentially all the molecules containing the one isotope is accomplished by a large number of chirped pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam.

  3. Isotope separation apparatus and method

    DOEpatents

    Cotter, Theodore P.

    1982-12-28

    The invention relates to a method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferable substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. The laser beam comprises .pi.-pulses of a selected wavelength which excite unexcited molecules, or cause stimulated emission of excited molecules of one of the isotopes. Excitation caused by first direction .pi.-pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning .pi.-pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement is accomplished by a large number of .pi.-pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam.

  4. Apparatus and process for separating hydrogen isotopes

    DOEpatents

    Heung, Leung K; Sessions, Henry T; Xiao, Xin

    2013-06-25

    The apparatus and process for separating hydrogen isotopes is provided using dual columns, each column having an opposite hydrogen isotopic effect such that when a hydrogen isotope mixture feedstock is cycled between the two respective columns, two different hydrogen isotopes are separated from the feedstock.

  5. Atomic vapor laser isotope separation

    SciTech Connect

    Stern, R.C.; Paisner, J.A.

    1985-11-08

    Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.

  6. The separation of stable isotopes of carbon

    NASA Astrophysics Data System (ADS)

    Oziashvili, E. D.; Egiazarov, A. S.

    1989-04-01

    The present state of work on the separation of carbon isotopes by diffusion, fractional distillation, chemical isotopic exchange, and the selective excitation and dissociation of molecules in electrical discharges or in the field of laser radiation has been examined. The characteristics of new laboratory and industrial assemblies for separating carbon isotopes have been described. Promising directions of study aimed at developing effective technological processes for separating carbon isotopes have been noted. The bibliography contains 148 references.

  7. Laser system for isotope separation

    NASA Astrophysics Data System (ADS)

    Shirayama, Shimpey; Mikatsura, Takefumi; Ueda, Hiroaki; Konagai, Chikara

    1990-06-01

    Atomic vapor laser isotope separation (AVLIS) is regarded as the most promising method to obtain srightly enriched economical nuclear fuel for a nuclear power plant. However, achieving a high power laser seems to be the bottle neck in its industrialization. In 1985, after successful development of high power lasers, the U.S. announced that AVLIS would be used for future methods of uranium enrichment. In Japan , Laser Atomic Separation Enrichment Research Associates of Japan (LASER-J), a joint Japanese utility companies research organization, was founded in April, 1987, to push a development program for laser uranium enrichment. Based on research results obtained from Japanese National Labs, and Universities , Laser-J is now constructing an AVLIS experimental facility at Tokai-mura. It is planned to have a 1-ton swu capacity per year in 1991. Previous to the experimental facility construction , Toshiba proceeded with the preliminary testing of an isotope separation system, under contract with Laser-J. Since the copper vapor laser (CVL) and the dye laser (DL) form a good combination , which can obtain high power tunable visible lights ,it is suitable to resonate uranium atoms. The laser system was built and was successfully operated in Toshiba for two years. The system consist of three copper vapor lasers , three dye lasers and appropriate o Atomic vapor laser isotope separation (AVLIS) is regarded as the most promising method to obtain srightly enriched economical nuclear fuel for a nuclear power plant. However, achieving a high power laser seems to be the bottle neck in its industrialization. In 1985, after successful development of high power lasers, the U.S. announced that AVLIS would be used for future methods of uranium enrichment. In Japan , Laser Atomic Separation Enrichment Research Associates of Japan (LASER-J) , a joint Japanese utility companies research organization , was founded in April, 1987, to push a development program for laser uranium enrichment

  8. Laser isotope separation of erbium and other isotopes

    DOEpatents

    Haynam, Christopher A.; Worden, Earl F.

    1995-01-01

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of .sup.167 Er. The hyperfine structure of .sup.167 Er was used to find two three-step photoionization pathways having a common upper energy level.

  9. Laser isotope separation of erbium and other isotopes

    DOEpatents

    Haynam, C.A.; Worden, E.F.

    1995-08-22

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of {sup 167}Er. The hyperfine structure of {sup 167}Er was used to find two three-step photoionization pathways having a common upper energy level. 3 figs.

  10. Efficient isotope separation by single-photon atomic sorting

    SciTech Connect

    Jerkins, M.; Chavez, I.; Raizen, M. G.; Even, U.

    2010-09-15

    We propose a general and scalable approach to isotope separation. The method is based on an irreversible change of the mass-to-magnetic moment ratio of a particular isotope in an atomic beam, followed by a magnetic multipole whose gradients deflect and guide the atoms. The underlying mechanism is a reduction of the entropy of the beam by the information of a single scattered photon for each atom that is separated. We numerically simulate isotope separation for a range of examples, which demonstrate this technique's general applicability to almost the entire periodic table. The practical importance of the proposed method is that large-scale isotope separation should be possible, using ordinary inexpensive magnets and the existing technologies of supersonic beams and lasers.

  11. Method of separating boron isotopes

    SciTech Connect

    Jensen, R.J.; Cluff, C.L.; Hayes, J.K.; Thorne, J.M.

    1984-05-08

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  12. Method of separating boron isotopes

    DOEpatents

    Jensen, R.J.; Thorne, J.M.; Cluff, C.L.

    1981-01-23

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)-dichloroborane as the feed material. The photolysis can readily by achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  13. Method of separating boron isotopes

    DOEpatents

    Jensen, Reed J.; Thorne, James M.; Cluff, Coran L.; Hayes, John K.

    1984-01-01

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO.sub.2 laser radiation and using fluences significantly below those required to dissociate BCl.sub.3.

  14. Hydrogen isotope separation installation for tritium facility

    SciTech Connect

    Andreev, B.M.; Perevezentsev, A.N.; Selivanenko, I.L.; Tenyaev, B.N.; Vedeneev, A.I.; Golubkov, A.N.

    1995-10-01

    The separation of hydrogen isotopes in the hydrogen-palladium system in sectioned separation columns with the simulation of counter-current isotopic exchange is described. The separation efficiency of sectioned columns is investigated with the experimental installation as a function of various parameters. The separation of deuterium-tritium mixtures with high tritium concentrations is tested with the pilot installation operating at room temperature and atmospheric hydrogen pressure. Due to very high separation efficiency, flexibility and simplicity of operation separation installations with sectioned columns are ideally suitable for tritium laboratories and facilities dealing with separation of hydrogen isotopes. Estimation of applicability of sectioned columns for regeneration of exhaust gas in a fuel cycle of thermonuclear reactors, such as JET and ITER, shows the number of advantages of separation installations with sectioned columns. 12 refs., 3 figs., 2 tabs.

  15. Method for isotope separation by photodeflection

    DOEpatents

    Bernhardt, Anthony F.

    1977-01-01

    In the method of separating isotopes wherein a desired isotope species is selectively deflected out of a beam of mixed isotopes by irradiating the beam with a directed beam of light of narrowly defined frequency which is selectively absorbed by the desired species, the improvement comprising irradiating the deflected beam with light from other light sources whose frequencies are selected to cause the depopulation of any metastable excited states.

  16. Possible application of laser isotope separation

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1975-01-01

    The laser isotope separation process is described and its special economic features discussed. These features are its low cost electric power operation, capital investment costs, and the costs of process materials.

  17. Atomic vapor laser isotope separation process

    DOEpatents

    Wyeth, R.W.; Paisner, J.A.; Story, T.

    1990-08-21

    A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.

  18. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, Charles G. [Pleasanton, CA

    1978-08-29

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, .sup.235 UF.sub.6 is separated from a UF.sub.6 mixture by selective excitation followed by dissociative electron capture into .sup.235 UF.sub.5 - and F.

  19. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, C.G.

    1978-08-29

    Disclosed is a method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, [sup 235]UF[sub 6] is separated from a UF[sub 6] mixture by selective excitation followed by dissociative electron capture into [sup 235]UF[sub 5]- and F. 2 figs.

  20. Hydrogen isotope separation from water

    DOEpatents

    Jensen, R.J.

    1975-09-01

    A process for separating tritium from tritium-containing water or deuterium enrichment from water is described. The process involves selective, laser-induced two-photon excitation and photodissociation of those water molecules containing deuterium or tritium followed by immediate reaction of the photodissociation products with a scavenger gas which does not substantially absorb the laser light. The reaction products are then separated from the undissociated water. (auth)

  1. Laser Isotope Separation Employing Condensation Repression

    SciTech Connect

    Eerkens, Jeff W.; Miller, William H.

    2004-09-15

    Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

  2. Device and method for separating oxygen isotopes

    DOEpatents

    Rockwood, Stephen D.; Sander, Robert K.

    1984-01-01

    A device and method for separating oxygen isotopes with an ArF laser which produces coherent radiation at approximately 193 nm. The output of the ArF laser is filtered in natural air and applied to an irradiation cell where it preferentially photodissociates molecules of oxygen gas containing .sup.17 O or .sup.18 O oxygen nuclides. A scavenger such as O.sub.2, CO or ethylene is used to collect the preferentially dissociated oxygen atoms and recycled to produce isotopically enriched molecular oxygen gas. Other embodiments utilize an ArF laser which is narrowly tuned with a prism or diffraction grating to preferentially photodissociate desired isotopes. Similarly, desired mixtures of isotopic gas can be used as a filter to photodissociate enriched preselected isotopes of oxygen.

  3. METHOD OF SEPARATING HYDROGEN ISOTOPES

    DOEpatents

    Salmon, O.N.

    1958-12-01

    The process of separating a gaseous mixture of hydrogen and tritium by contacting finely dlvided palladium with the mixture in order to adsorb the gases, then gradually heating the palladium and collecting the evolved fractlons, is described. The fraction first given off is richer in trltium than later fractions.

  4. Isotope separation and advanced manufacturing technology

    NASA Astrophysics Data System (ADS)

    Carpenter, J.; Kan, T.

    This is the fourth issue of a semiannual report for the Isotope Separation and Advanced Materials Manufacturing (ISAM) Technology Program at Lawrence Livermore National Laboratory. Primary objectives include: (1) the Uranium Atomic Vapor Laser Isotope Separation (UAVLIS) process, which is being developed and prepared for deployment as an advanced uranium enrichment capability; (2) Advanced manufacturing technologies, which include industrial laser and E-beam material processing and new manufacturing technologies for uranium, plutonium, and other strategically important materials in support of DOE and other national applications. This report features progress in the ISAM Program from October 1993 through March 1994.

  5. Beam delivery for stable isotope separation

    NASA Astrophysics Data System (ADS)

    Forbes, Andrew; Strydom, Hendrick J.; Botha, Lourens R.; Ronander, Einar

    2002-10-01

    In the multi-photon dissociation process of Carbon isotope enrichment, IR photons are used to selectively excite a molecule with the given isotopic base element. This enrichment process is very sensitive to the beam's intensity and wavelength. Because the intensity is determined by the propagation of the field, the enrichment factors are also very dependent on the field propagation. In this paper, the influence of the wavelength and intensity of the beam, on the isotope selective dissociation of a CFC compound is investigated both experimentally and theoretically. Consideration is also given to some of the factors that influence the delivery of various beams to the reactor chamber, and their subsequent propagation through the reactor. The results show that suitable beam forming can lead to an improved isotope separation process.

  6. Apparatus for separating and recovering hydrogen isotopes

    DOEpatents

    Heung, Leung K.

    1994-01-01

    An apparatus for recovering hydrogen and separating its isotopes. The apparatus includes a housing bearing at least a fluid inlet and a fluid outlet. A baffle is disposed within the housing, attached thereto by a bracket. A hollow conduit is coiled about the baffle, in spaced relation to the baffle and the housing. The coiled conduit is at least partially filled with a hydride. The hydride can be heated to a high temperature and cooled to a low temperature quickly by circulating a heat transfer fluid in the housing. The spacing between the baffle and the housing maximizes the heat exchange rate between the fluid in the housing and the hydride in the conduit. The apparatus can be used to recover hydrogen isotopes (protium, deuterium and tritium) from gaseous mixtures, or to separate hydrogen isotopes from each other.

  7. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, R.J.; Cecchi, J.L.

    1991-08-20

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

  8. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, Randall J.; Cecchi, Joseph L.

    1990-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  9. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, Randall J.; Cecchi, Joseph L.

    1991-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  10. Hydrogen isotope separation utilizing bulk getters

    SciTech Connect

    Knize, R.J.; Cecchi, J.L.

    1990-12-11

    This patent describes hydrogen isotope separation utilizing bulk getters. Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  11. Laser isotope separation by multiple photon absorption

    DOEpatents

    Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

    1987-04-07

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

  12. Laser isotope separation by multiple photon absorption

    DOEpatents

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1987-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  13. Laser isotope separation by multiple photon absorption

    DOEpatents

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1977-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, in the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  14. Separation of isotopes by cyclical processes

    DOEpatents

    Hamrin, Jr., Charles E.; Weaver, Kenny

    1976-11-02

    Various isotopes of hydrogen are separated by a cyclic sorption process in which a gas stream containing the isotopes is periodically passed through a high pressure column containing a palladium sorbent. A portion of the product from the high pressure column is passed through a second column at lower pressure to act as a purge. Before the sorbent in the high pressure column becomes saturated, the sequence is reversed with the stream flowing through the former low-pressure column now at high pressure, and a portion of the product purging the former high pressure column now at low pressure. The sequence is continued in cyclic manner with the product being enriched in a particular isotope.

  15. Separation of uranium isotopes by chemical exchange

    DOEpatents

    Ogle, P.R. Jr.

    1974-02-26

    A chemical exchange method is provided for separating /sup 235/U from / sup 238/U comprising contacting a first phase containing UF/sub 6/ with a second phase containing a compound selected from the group consisting of NOUF/sub 6/, NOUF/sub 7/, and NO/sub 2/UF/sub 7/ until the U Fsub 6/ in the first phase becomes enriched in the /sup 235/U isotope. (Official Gazette)

  16. Hydrograph separation using stable isotopes: Review and evaluation

    NASA Astrophysics Data System (ADS)

    Klaus, J.; McDonnell, J. J.

    2013-11-01

    We reviewed isotope hydrograph separation studies.We examine methods, applications, and limitations.We summarize factors that control the event/pre-event water contributions.We outline new possible research avenues in isotope hydrograph separation.

  17. Laser-assisted isotope separation of tritium

    DOEpatents

    Herman, Irving P.; Marling, Jack B.

    1983-01-01

    Methods for laser-assisted isotope separation of tritium, using infrared multiple photon dissociation of tritium-bearing products in the gas phase. One such process involves the steps of (1) catalytic exchange of a deuterium-bearing molecule XYD with tritiated water DTO from sources such as a heavy water fission reactor, to produce the tritium-bearing working molecules XYT and (2) photoselective dissociation of XYT to form a tritium-rich product. By an analogous procedure, tritium is separated from tritium-bearing materials that contain predominately hydrogen such as a light water coolant from fission or fusion reactors.

  18. CONTROL SYSTEM FOR ISOTOPE SEPARATING APPARATUS

    DOEpatents

    Barnes, S.W.

    1960-01-26

    A method is described for controlling the position of the ion beams in a calutron used for isotope separation. The U/sup 238/ beams is centered over the U/sup 235/ receiving pocket, the operator monitoring the beam until a maximum reading is achieved on the meter connected to that pocket. Then both beams are simultaneously shifted by a preselected amount to move the U/sup 235/ beam over the U/sup 235/ pocket. A slotted door is placed over the entrance to that pocket during the U/sup 238/ beam centering to reduce the contamination to the pocket, while allowing enough beam to pass for monitoring purposes.

  19. Photolytic separation of isotopes in cryogenic solution

    DOEpatents

    Freund, S.M.; Maier, W.B. II; Holland, R.F.; Battie, W.H.

    Separation of carbon isotopes by photolysis of CS/sub 2/ in cryogenic solutions of nitrogen, krypton and argon with 206 nm light from an iodine resonance lamp is reported. The spectral distributionn of the ultraviolet absorption depends on solvent. Thus, in liquid nitrogen the photolytic decomposition rate of /sup 13/CS/sub 2/ is greater than that of /sup 12/CS/sub 2/ (because the absorption of 206 nm radiation is greater for /sup 13/CS/sub 2/), whereas in liquid krypton and liquid argon the reverse is true. The shift in ultraviolet spectrum is a general phenomenon readily characterized as a function of solvent polarizability, and exhibits behavior similar to that for vibrational transitions occurring in the infrared.

  20. Photolytic separation of isotopes in cryogenic solution

    DOEpatents

    Freund, Samuel M.; Maier, II, William B.; Holland, Redus F.; Beattie, Willard H.

    1985-01-01

    Separation of carbon isotopes by photolysis of CS.sub.2 in cryogenic solutions of nitrogen, krypton and argon with 206 nm light from an iodine resonance lamp is reported. The spectral distribution of the ultraviolet absorption depends on solvent. Thus, in liquid nitrogen the photolytic decomposition rate of .sup.13 CS.sub.2 is greater than that of .sup.12 CS.sub.2 (because the absorption of 206 nm radiation is greater for .sup.13 CS.sub.2), whereas in liquid krypton and liquid argon the reverse is true. The shift in ultraviolet spectrum is a general phenomenon readily characterized as a function of solvent polarizability, and exhibits behavior similar to that for vibrational transitions occurring in the infrared.

  1. Novel hybrid isotope separation scheme and apparatus

    DOEpatents

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means.

  2. Novel hybrid isotope separation scheme and apparatus

    DOEpatents

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means. 3 figures.

  3. Method of isotope separation by chemi-ionization

    DOEpatents

    Wexler, Sol; Young, Charles E.

    1977-05-17

    A method for separating specific isotopes present in an isotopic mixture by aerodynamically accelerating a gaseous compound to form a jet of molecules, and passing the jet through a stream of electron donor atoms whereby an electron transfer takes place, thus forming negative ions of the molecules. The molecular ions are then passed through a radiofrequency quadrupole mass filter to separate the specific isotopes. This method may be used for any compounds having a sufficiently high electron affinity to permit negative ion formation, and is especially useful for the separation of plutonium and uranium isotopes.

  4. Isotope separation by selective photodissociation of glyoxal

    DOEpatents

    Marling, John B.

    1976-01-01

    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 of a predetermined wavelength such that photon absorption excites and induces dissociation of only those molecules of glyoxal containing the desired isotope.

  5. A LINEAR PROGRAMMING MODEL OF THE GASEOUSDIFFUSION ISOTOPE-SEPARATION PROCESS,

    DTIC Science & Technology

    ISOTOPE SEPARATION, LINEAR PROGRAMMING ), (*GASEOUS DIFFUSION SEPARATION, LINEAR PROGRAMMING ), (* LINEAR PROGRAMMING , GASEOUS DIFFUSION SEPARATION), NUCLEAR REACTORS, REACTOR FUELS, URANIUM, PURIFICATION

  6. Cost Estimate for Laser Isotope Separation for RIA

    SciTech Connect

    Scheibner, K

    2004-11-01

    Isotope enrichment of some elements is required in support of the Rare Isotope Accelerator (RIA) in order to obtain the beam intensities, source efficiencies and/or source lifetime required by RIA. The economics of using Atomic Vapor Laser Isotope Separation (AVLIS) technology as well as ElectroMagnetic (EM) separation technology has been evaluated. It is concluded that such an AVLIS would be about 10 times less expensive than a facility based on electromagnetic separation - $17 M versus $170 M. In addition, the AVLIS facility footprint would be about 10 times smaller, and operations would require about 4 years (including 2 years of startup) versus about 11 years for an EM facility.

  7. Isotope separation by photodissociation of Van der Waal's molecules

    DOEpatents

    Lee, Yuan T.

    1977-01-01

    A method of separating isotopes based on the dissociation of a Van der Waal's complex. A beam of molecules of a Van der Waal's complex containing, as one partner of the complex, a molecular species in which an element is present in a plurality of isotopes is subjected to radiation from a source tuned to a frequency which will selectively excite vibrational motion by a vibrational transition or through electronic transition of those complexed molecules of the molecular species which contain a desired isotope. Since the Van der Waal's binding energy is much smaller than the excitational energy of vibrational motion, the thus excited Van der Waal's complex dissociate into molecular components enriched in the desired isotope. The recoil velocity associated with vibrational to translational and rotational relaxation will send the separated molecules away from the beam whereupon the product enriched in the desired isotope can be separated from the constituents of the beam.

  8. Helical path separation for guided wave tomography

    SciTech Connect

    Huthwaite, P.; Seher, M.

    2015-03-31

    The pipe wall loss caused by corrosion can be quantified across an area by transmitting guided Lamb waves through the region and measuring the resulting signals. Typically the dispersive relationship for these waves, resulting in the wave velocity being a function of thickness, is exploited which enables the wall thickness to be determined from a velocity reconstruction. The accuracy and quality of this reconstruction is commonly limited by the angle of view available from the transducer arrays. These arrays are often attached as a pair of ring arrays either side of the inspected region, and due to the cyclic nature of the pipe, waves are able to travel in an inifinite number of helical paths between any two transducers. The first arrivals can be separated relatively easily by time gating, but by using just these components the angle of view is strongly restricted. To improve the viewing angle, it is necessary to separate the wavepackets. This paper provides an outline of a separation approach: initially the waves are backpropagated to their source to align the different signals, then a filtering technique is applied to select the desired components. The technique is applied to experimental data and demonstrated to robustly separate the signals.

  9. VELOCITY SELECTOR METHOD FOR THE SEPARATION OF ISOTOPES

    DOEpatents

    Britten, R.J.

    1957-12-31

    A velocity selector apparatus is described for separating and collecting an enriched fraction of the isotope of a particular element. The invention has the advantage over conventional mass spectrometers in that a magnetic field is not used, doing away with the attendant problems of magnetic field variation. The apparatus separates the isotopes by selectively accelerating the ionized constituents present in a beam of the polyisotopic substance that are of uniform kinetic energy, the acceleration being applied intermittently and at spaced points along the beam and in a direction normal to the direction of the propagation of the uniform energy beam whereby a transverse displacement of the isotopic constituents of different mass is obtained.

  10. Cascades for hydrogen isotope separation using metal hydrides

    SciTech Connect

    Hill, F.B.; Grzetic, V.

    1982-01-01

    Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes.

  11. Electromagnetic separation of stable isotopes at China Institute of Atomic Energy

    NASA Astrophysics Data System (ADS)

    Meiqin, Xiao; Hongyou, Lu; Shijun, Su; Zhizhou, Lin

    1993-09-01

    Electromagnetic separation of stable isotopes at CIAE is described. The separators, the ion sources used, the isotopes separated and their applications are introduced. The improvement of a 180° production separator is also described.

  12. Atomic vapor laser isotope separation of lead-210 isotope

    DOEpatents

    Scheibner, Karl F.; Haynam, Christopher A.; Johnson, Michael A.; Worden, Earl F.

    1999-01-01

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207.

  13. Atomic vapor laser isotope separation of lead-210 isotope

    SciTech Connect

    Scheibner, K.F.; Haynam, C.A.; Johnson, M.A.; Worden, E.F.

    1999-08-31

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207. 5 figs.

  14. Production of stable isotopes utilizing the plasma separation process

    NASA Astrophysics Data System (ADS)

    Bigelow, T. S.; Tarallo, F. J.; Stevenson, N. R.

    2005-12-01

    A plasma separation process (PSP) is being operated at Theragenics Corporation's®, Oak Ridge, TN, facility for the enrichment of stable isotopes. The PSP utilizes ion cyclotron mass discrimination to separate isotopes on a relatively large scale. With a few exceptions, nearly any metallic element could be processed with PSP. Output isotope enrichment factor depends on natural abundance and mass separation and can be fairly high in some cases. The Theragenics™ PSP facility is believed to be the only such process currently in operation. This system was developed and formerly operated under the US Department of Energy Advanced Isotope Separation program. Theragenics™ also has a laboratory at the PSP site capable of harvesting the isotopes from the process and a mass spectrometer system for analyzing enrichment and product purity. Since becoming operational in 2002, Theragenics™ has utilized the PSP to separate isotopes of several elements including: dysprosium, erbium, gadolinium, molybdenum and nickel. Currently, Theragenics™ is using the PSP for the separation of 102Pd, which is used as precursor for the production of 103Pd. The 103Pd radioisotope is the active ingredient in TheraSeed®, which is used in the treatment of early stage prostate cancer and being investigated for other medical applications. New industrial, medical and research applications are being investigated for isotopes that can be enriched on the PSP. Pre-enrichment of accelerator or reactor targets offers improved radioisotope production. Theragenics operates 14 cyclotrons for proton activation and has access to HFIR at ORNL for neutron activation of radioisotopes.

  15. Nitrogen isotopes of the mantle: Insights from mineral separates

    NASA Astrophysics Data System (ADS)

    Fischer, Tobias P.; Takahata, Naoto; Sano, Yuji; Sumino, Hirochika; Hilton, David R.

    2005-06-01

    We present the first nitrogen (N) isotope measurements determined by in-vacuo crushing of mineral separates from arc lavas, OIBs (Ocean Island Basalts), and mantle xenoliths. Measured OIB δ15N values range from ~-8‰ for the northern rift zone in Iceland to +3.1‰ for a dunite nodule from Hawaii. Most arc-related olivines show distinctly positive values - up to +6.2‰ (Cerro Negro, Nicaragua). The measured N isotope values in olivine separates are similar to gas samples collected at the same localities, suggesting that both media (olivines and gases) sample volatiles primarily derived from the magma. This observation also implies that N isotope fractionation does not occur during magma degassing, a notion supported by 4He/40Ar* data. Our results indicate a heterogeneous mantle source region, in terms of N isotopic composition, that may have resulted from surface recycling of N at some localities.

  16. Investigation of the Photochemical Method for Uranium Isotope Separation

    DOE R&D Accomplishments Database

    Urey, H. C.

    1943-07-10

    To find a process for successful photochemical separation of isotopes several conditions have to be fulfilled. First, the different isotopes have to show some differences in the spectrum. Secondly, and equally important, this difference must be capable of being exploited in a photochemical process. Parts A and B outline the physical and chemical conditions, and the extent to which one might expect to find them fulfilled. Part C deals with the applicability of the process.

  17. Separation of the isotopes of boron by chemical exchange reactions

    DOEpatents

    McCandless, Frank P.; Herbst, Ronald S.

    1995-01-01

    The isotopes of boron, .sup.10 B and .sup.11 B, are separated by means of a gas-liquid chemical exchange reaction involving the isotopic equilibrium between gaseous BF.sub.3 and a liquid BF.sub.3 . donor molecular addition complex formed between BF.sub.3 gas and a donor chosen from the group consisting of: nitromethane, acetone, methyl isobutyl ketone, or diisobutyl ketone.

  18. Separation of the isotopes of boron by chemical exchange reactions

    DOEpatents

    McCandless, F.P.; Herbst, R.S.

    1995-05-30

    The isotopes of boron, {sup 10}B and {sup 11}B, are separated by means of a gas-liquid chemical exchange reaction involving the isotopic equilibrium between gaseous BF{sub 3} and a liquid BF{sub 3} donor molecular addition complex formed between BF{sub 3} gas and a donor chosen from the group consisting of: nitromethane, acetone, methyl isobutyl ketone, or diisobutyl ketone. 1 Fig.

  19. METHOD TO TEST ISOTOPIC SEPARATION EFFICIENCY OF PALLADIUM PACKED COLUMNS

    SciTech Connect

    Heung, L; Gregory Staack, G; James Klein, J; William Jacobs, W

    2007-06-27

    The isotopic effect of palladium has been applied in different ways to separate hydrogen isotopes for many years. At Savannah River Site palladium deposited on kieselguhr (Pd/k) is used in a thermal cycling absorption process (TCAP) to purify tritium for over ten years. The need to design columns for different throughputs and the desire to advance the performance of TCAP created the need to evaluate different column designs and packing materials for their separation efficiency. In this work, columns with variations in length, diameter and metal foam use, were tested using an isotope displacement method. A simple computer model was also developed to calculate the number of theoretical separation stages using the test results. The effects of column diameter, metal foam and gas flow rate were identified.

  20. Pulsed CO laser for isotope separation of uranium

    SciTech Connect

    Baranov, Igor Y.; Koptev, Andrey V.

    2012-07-30

    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.

  1. Chromatographic separation of neodymium isotopes by using chemical exchange process.

    PubMed

    Ismail, I M; Ibrahim, M; Aly, H F; Nomura, M; Fujii, Y

    2011-05-20

    The neodymium isotope effects were investigated in Nd-malate ligand exchange system using the highly porous cation exchange resin SQS-6. The temperature of the chromatographic columns was kept constant at 50°C by temperature controlled water passed through the columns jackets. The separation coefficient of neodymium isotopes, ɛ's, was calculated from the isotopic ratios precisely measured by means of an ICP mass spectrometer equipped with nine collectors as ion detectors. The separation coefficient, ɛ×10(5), were calculated and found to be 1.4, 4.8, 5.4, 10.6, 16.8 and 20.2 for (143)Nd, (144)Nd, (145)Nd, (146)Nd, (148)Nd and (150)Nd, respectively.

  2. Production of rare isotope beams with the NSCL fragment separator

    NASA Astrophysics Data System (ADS)

    Stolz, A.; Baumann, T.; Ginter, T. N.; Morrissey, D. J.; Portillo, M.; Sherrill, B. M.; Steiner, M.; Stetson, J. W.

    2005-12-01

    Rare isotope beams at the National Superconducting Cyclotron Laboratory are produced by projectile fragmentation of medium energy primary beams on beryllium targets. The fragments of interest are selected by the A1900 high-acceptance fragment separator. The A1900 consists of superconducting magnets: four 45° dipoles and eight quadrupole triplets with a maximum magnetic rigidity of 6 Tm. A momentum acceptance of Δp/p = 5% with a solid angle acceptance of ΔΩ = 8 msr makes the A1900 one of the highest-acceptance separators in the world. Detector systems installed within the device allow tracking and unambiguous identification of individual isotopes. During the first three years of operation of the A1900, more than 200 different rare isotope beams approaching both the neutron and proton driplines have been delivered to experiments.

  3. THE SEPARATION OF URANIUM ISOTOPES BY GASEOUS DIFFUSION: A LINEAR PROGRAMMING MODEL,

    DTIC Science & Technology

    URANIUM, ISOTOPE SEPARATION), (*GASEOUS DIFFUSION SEPARATION, LINEAR PROGRAMMING ), (* LINEAR PROGRAMMING , GASEOUS DIFFUSION SEPARATION), MATHEMATICAL MODELS, GAS FLOW, NUCLEAR REACTORS, OPERATIONS RESEARCH

  4. Gas chromatographic separation of hydrogen isotopes using metal hydrides

    SciTech Connect

    Aldridge, F.T.

    1984-05-09

    A study was made of the properties of metal hydrides which may be suitable for use in chromatographic separation of hydrogen isotopes. Sixty-five alloys were measured, with the best having a hydrogen-deuterium separation factor of 1.35 at 60/sup 0/C. Chromatographic columns using these alloys produced deuterium enrichments of up to 3.6 in a single pass, using natural abundance hydrogen as starting material. 25 references, 16 figures, 4 tables.

  5. RECTIFIED ABSORPTION METHOD FOR THE SEPARATION OF HYDROGEN ISOTOPES

    DOEpatents

    Hunt, C.D.; Hanson, D.N.

    1961-10-17

    A method is described for separating and recovering heavy hydrogen isotopes from gaseous mixtures by multiple stage cyclic absorption and rectification from an approximate solvent. In particular, it is useful for recovering such isoteoes from ammonia feedstock streams containing nitrogen solvent. Modifications of the process ranging from isobaric to isothermal are provided. Certain impurities are tolerated, giving advantages over conventional fractional distillation processes. (AEC)

  6. An ion guide laser ion source for isobar-suppressed rare isotope beams

    SciTech Connect

    Raeder, Sebastian Ames, Friedhelm; Bishop, Daryl; Bricault, Pierre; Kunz, Peter; Mjøs, Anders; Heggen, Henning; Lassen, Jens Teigelhöfer, Andrea

    2014-03-15

    Modern experiments at isotope separator on-line (ISOL) facilities like ISAC at TRIUMF often depend critically on the purity of the delivered rare isotope beams. Therefore, highly selective ion sources are essential. This article presents the development and successful on-line operation of an ion guide laser ion source (IG-LIS) for the production of ion beams free of isobaric contamination. Thermionic ions from the hot ISOL target are suppressed by an electrostatic potential barrier, while neutral radio nuclides effusing out are resonantly ionized by laser radiation within a quadrupole ion guide behind this barrier. The IG-LIS was developed through detailed thermal and ion optics simulation studies and off-line tests with stable isotopes. In a first on-line run with a SiC target a suppression of surface-ionized Na contaminants in the ion beam of up to six orders of magnitude was demonstrated.

  7. Rotation and instabilities for isotope and mass separation

    NASA Astrophysics Data System (ADS)

    Rax, J.-M.; Gueroult, R.

    2016-10-01

    Rotating plasmas have the potential to offer unique capabilities for isotope and mass separation. Among the various electric and magnetic field configurations offering mass separation capabilities, rotating plasmas produced through static or oscillating fields are shown to be a leading candidate for tackling the unsolved problem of large-scale plasma separation. The successful development and deployment of industrial-scale plasma separation technologies could, among many other applications, provide an innovative path towards advanced sustainable nuclear energy. In this context, the potential and versatility of plasma rotation induced by rotating magnetic fields is uncovered and analysed. Analytical stability diagrams are derived from rotating ion orbits as a function of ion mass. Based on these findings, the basic principles of a rotating field plasma separator are then introduced. In light of these results, challenges associated with this original separation process are underlined, and the main directions for a future research program aimed at this important unsolved problem of applied plasma physics are identified.

  8. Atomic vapor laser isotope separation using resonance ionization

    SciTech Connect

    Comaskey, B.; Crane, J.; Erbert, G.; Haynam, C.; Johnson, M.; Morris, J.; Paisner, J.; Solarz, R.; Worden, E.

    1986-09-01

    Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power-reactor fuel has been under development for over 10 years. In June 1985, the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for enriched uranium. Resonance photoionization is the heart of the AVLIS process. We discuss those fundamental atomic parameters that are necessary for describing isotope-selective resonant multistep photoionization along with the measurement techniques that we use. We illustrate the methodology adopted with examples of other elements that are under study in our program.

  9. Biomedical research applications of electromagnetically separated enriched stable isotopes

    NASA Astrophysics Data System (ADS)

    Lambrecht, R. M.

    The current and projected annual requirements through 1985 for stable isotopes enriched by electromagnetic separation methods were reviewed for applications in various types of biomedical research: (1) medical radiosiotope production, labeled compounds, and potential radio-pharmaceuticals; (2) nutrition, food science, and pharmacology: (3) metallobiochemistry and environmental toxicology; (4) nuclear magnetic resonance, electron paramagnetic resonance, and moessbauer spectroscopy in biochemical, biophysical, and biomedical research; and (5) miscellaneous advances in radioactive and nonradioactive tracer technology. Radioisotopes available from commercial sources or routinely used in clinical nuclear medicine were excluded. Current requirements for enriched stable isotopes in biomedical research are not being satisfied. Severe shortages exist for Mg 26, Ca 43, Zn 70, Se 76, Se 77, Se 78, Pd 102, Cd 111, Cd 113, and Os 190. Many interesting and potentially important investigations in biomedical research require small quantities of specific elements at high isotopic enrichments.

  10. Advancement of isotope separation for the production of reference standards

    SciTech Connect

    Jared Horkley; Christopher McGrath; Andrew Edwards; Gaven Knighton; Kevin Carney; Jacob Davies; James Sommers; Jeffrey Giglio

    2012-03-01

    Idaho National Laboratory (INL) operates a mass separator that is currently producing high purity isotopes for use as internal standards for high precision isotope dilution mass spectrometry (IDMS). In 2008, INL began the revival of the vintage 1970’s era instrument. Advancements thus far include the successful upgrading and development of system components such as the vacuum system, power supplies, ion-producing components, and beam detection equipment. Progress has been made in the separation and collection of isotopic species including those of Ar, Kr, Xe, Sr, and Ba. Particular focuses on ion source improvements and developments have proven successful with demonstrated output beam currents of over 10 micro-amps 138Ba and 350nA 134Ba from a natural abundance source charge (approximately 2.4 percent 134Ba). In order to increase production and collection of relatively high quantities (mg levels) of pure isotopes, several advancements have been made in ion source designs, source material introduction, and beam detection and collection. These advancements and future developments will be presented.

  11. An isotope separator for small noble gas samples

    NASA Astrophysics Data System (ADS)

    Lehmann, B. E.; Rauber, D. F.; Thonnard, N.; Willis, R. D.

    1987-11-01

    A Wien filter isotope enrichment system has been combined with a small turbomolecular pump to form a closed isotope separator for small noble gas samples. Atoms which leave the exit aperture of the plasma discharge ion source without being ionized are circulated back into the source through a feedback line. The system can be operated for several hours in a closed mode to collect up to 50% of the total number of atoms of a selected isotope (e.g. 81Kr) out of a small gas sample of only 2 × 10 -3 cm 3 STP. Ions are implanted at 10 kV into an aluminized Kapton foil after a flight distance of 150 cm. A beam stabilization system centers the ion beam in two perpendicular directions onto a target aperture to maintain a high enrichment factor of at least 10 3 over extended periods of time. Calibration of the enrichment process is achieved by isotope dilution. The system is a key part of the sample processing for 81Kr and 85Kr analysis by laser resonance ionization spectroscopy for applications in isotope geophysics.

  12. Development of Halide and Oxy-Halides for Isotopic Separations

    SciTech Connect

    Martin, Leigh R.; Johnson, Aaron T.; Pfeiffer, Jana; Finck, Martha R.

    2014-10-01

    The goal of this project was to synthesize a volatile form of Np for introduction into mass spectrometers at INL. Volatile solids of the 5f elements are typically those of the halides (e.g. UF6), however fluorine is highly corrosive to the sensitive internal components of the mass separator, and the other volatile halides exist as several different stable isotopes in nature. However, iodide is both mono-isotopic and volatile, and as such presents an avenue for creation of a form of Np suitable for introduction into the mass separator. To accomplish this goal, the technical work in the project sought to establish a novel synthetic route for the conversion NpO2+ (dissolved in nitric acid) to NpI3 and NpI4.

  13. NOVEL CONCEPTS FOR ISOTOPIC SEPARATION OF 3HE/4HE

    SciTech Connect

    Roy, L.; Nigg, H.; Watson, H.

    2012-09-04

    The research outlined below established theoretical proof-of-concept using ab initio calculations that {sup 3}He can be separated from {sup 4}He by taking advantage of weak van der Waals interactions with other higher molecular weight rare gases such as xenon. To the best of our knowledge, this is the only suggested method that exploits the physical differences of the isotopes using a chemical interaction.

  14. Uranium isotope separation from 1941 to the present

    NASA Astrophysics Data System (ADS)

    Maier-Komor, Peter

    2010-02-01

    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.

  15. Isotopic separation of lithium ions by capillary zone electrophoresis.

    PubMed

    Kamencev, Mikhail; Yakimova, Nina; Moskvin, Leonid; Kuchumova, Irina; Tkach, Kirill; Malinina, Yulia; Tungusov, Oleg

    2015-12-01

    Separation of (6)Li and (7)Li isotopes by CZE was demonstrated. The BGE contained 5 mM 4-aminopyridine, 0.9 mM oxalic acid, 0.25 mM CTAB, and 0.25% w/v Tween 20 (рН = 9.2). The running conditions were +25 kV at 30°C with indirect photometric detection at 261 nm. Under optimal experimental conditions, the analysis time was less than 21 min. Separation of Li preparations with mole fraction of (6)Li ranging from 3.44 up to 90.38% was demonstrated.

  16. Methods for separating medical isotopes using ionic liquids

    DOEpatents

    Luo, Huimin; Boll, Rose Ann; Bell, Jason Richard; Dai, Sheng

    2014-10-21

    A method for extracting a radioisotope from an aqueous solution, the method comprising: a) intimately mixing a non-chelating ionic liquid with the aqueous solution to transfer at least a portion of said radioisotope to said non-chelating ionic liquid; and b) separating the non-chelating ionic liquid from the aqueous solution. In preferred embodiments, the method achieves an extraction efficiency of at least 80%, or a separation factor of at least 1.times.10.sup.4 when more than one radioisotope is included in the aqueous solution. In particular embodiments, the method is applied to the separation of medical isotopes pairs, such as Th from Ac (Th-229/Ac-225, Ac-227/Th-227), or Ra from Ac (Ac-225 and Ra-225, Ac-227 and Ra-223), or Ra from Th (Th-227 and Ra-223, Th-229 and Ra-225).

  17. Guide to plutonium isotopic measurements using gamma-ray spectrometry

    SciTech Connect

    Lemming, J.F.; Rakel, D.A.

    1982-08-26

    Purpose of this guide is to assist those responsible for plutonium isotopic measurements in the application of gamma-ray spectrometry. Objectives are to promote an understanding of the measurement process, including its limitations and applicability, by reviewing the general features of a plutonium spectrum and identifying the quantities which must be extracted from the data; to introduce state-of-the-art analysis techniques by reviewing four isotopic analysis packages and identifying their differences; to establish the basis for measurement control and assurance by discussing means of authenticating the performance of a measurement system; and to prepare for some specific problems encountered in plutonium isotopic analyses by providing solutions from the practical experiences of several laboratories. 29 references, 12 figures, 17 tables.

  18. Stable isotope enrichment techniques and ORNL separation status

    NASA Astrophysics Data System (ADS)

    Tracy, J. G.; Bell, W. A.; Veach, A. M.; Caudill, H. H.; Milton, H. T.

    1987-05-01

    The isotope separation program is described, emphasizing present state-of-the-art techniques utilized to achieve specific isotopic requirements. An interesting problem addressed here is the calutron enrichment of rare-earth isotopes where small quantities of feed (< 5 g) are available, and the unresolved feed is to be recovered and recycled. Conventional ion-source units using graphite and stainless steel deteriorate in the halogenating atmosphere or are permeable to rare-earth compounds, reducing the process efficiency. An ion source has been developed using boron nitride for containing the halogenating agent and rare-earth compounds. Tests have been successfully conducted using Lu 2O 3 and the in situ chlorinating technique with CCl 4. Collectively, 166 mg of 176Lu were recovered from two runs using 2.95 and 1.10 g of 44.5% 176Lu. Process efficiency of 10.5% was achieved, and 1.2 g of the unresolved feed were recovered. Material compatibility of the boron nitride, carbon tetrachloride, and lutetium compounds has been established.

  19. Laser photochemical lead isotopes separation for harmless nuclear power engineering

    NASA Astrophysics Data System (ADS)

    Bokhan, P. A.; Fateev, N. V.; Kim, V. A.; Zakrevsky, D. E.

    2016-09-01

    The collisional quenching of the metastable 3 P 1,2 and 1 D 2 lead atoms is studied experimentally in the gas flow of the lead atoms, reagent-molecules and a carrier gas Ar. The experimental parameters were similar to the conditions that are required in the operation of the experimental setup for photochemical isotope separation. Excited atoms are generated under electron impact conditions created by a gas glow discharge through the mixture of gases and monitored photoelectrically by attenuation of atomic resonance radiation from hollow cathode 208Pb lamp. The decay of the excited atoms has been studied in the presence various molecules and total cross section data are reported. The flow tube measurements has allowed to separate the physical and chemical quenching channels and measure the rates of the chemical reaction excited lead with N2O, CH2Cl2, SF6 and CuBr molecules. These results are discussed in the prospects of the obtaining isotopically modified lead as a promising coolant in the reactors on the fast-neutron.

  20. University Isotope Separator at Oak Ridge: The UNISOR Consortium.

    PubMed

    Hamilton, J H

    1974-09-06

    The UNISOR cooperative project, envisioned more than 3 years ago, is now successfully working. Research problems that involve a full range of experiments on nuclei far from beta stability are being investigated jointly by groups of scientists from several institutions. Some of the first work reported (16) included the identification, half-lives, and decay schemes of three new isotopes, (186)T1, (188)T1, and (116)I; the first or new decay schemes of (189)T1, (190)T1, (117)Xe, and (117)I; and the results of the perturbed gamma-gamma directional correlation work in (126)Xe. UNISOR is already stimulating international interest. A report (1) on the new research being planned with an isotope separator on-line to ORIC was presented at a Soviet Academy of Sciences meeting on nuclear structure in 1971. At an international nuclear physics conference in Munich in August 1973, Academician G. N. Flerov, director of the heavy-ion laboratory in Dubna, said the UNISOR project had inspired his laboratory to secure funds for a new, much improved isotope separator which is now installed on-line to their heavy-ion cyclotron to be used for detailed studies of nuclei far from stability. The UNISOR model for research has inspired a second such project, the Atomic Physics Consortium at Oak Ridge (APCOR). After an exploratory conference at Oak Ridge, scientists from ten institutions met in November 1973 to form an organizing committee for APCOR. As with UNISOR, the universities and the AEC will each provide a significant portion of the capital and operating costs. Heavy ions have opened up much new research in atomic physics, but such accelerator-based research represents a real "shift from traditional approaches concerning how, where, and on what time scale atomic physics experiments should be done" (17).

  1. INSTRUMENTS AND METHODS OF INVESTIGATION: Plasma isotope separation based on ion cyclotron resonance

    NASA Astrophysics Data System (ADS)

    Dolgolenko, Dmitrii A.; Muromkin, Yurii A.

    2009-04-01

    Experiments that have been conducted in the USA, France, and Russia to investigate isotopically selective ion cyclotron resonance (ICR) as a tool for plasma isotope separation are analyzed. Because this method runs into difficulties at low values of the relative isotope mass difference ΔM/M, for some elements (for gadolinium, as an example) isotope separation still remains a problem. There are ways to solve it, however, as experimental results and theoretical calculations suggest.

  2. Tritium Isotope Separation Using Adsorption-Distillation Column

    SciTech Connect

    Fukada, Satoshi

    2005-07-15

    In order to miniaturize the height of a distillation tower for the detritiation of waste water from fusion reactors, two experiments were conducted: (1) liquid frontal chromatography of tritium water eluting through an adsorption column and (2) water distillation using a column packed with adsorbent particles. The height of the distillation tower depends on the height equivalent to a theoretical plate, HETP, and the equilibrium isotope separation factor, {alpha}{sub H-T}{sup equi}. The adsorption action improved not only HETP but also {alpha}{sub H-T}{sup equi}. Since the adsorption-distillation method proposed here can shorten the tower height with keeping advantages of the distillation, it may bring an excellent way for miniaturizing the distillation tower to detritiate a large amount of waste water from fusion reactors.

  3. Separated isotopes: vital tools for science and medicine

    SciTech Connect

    Not Available

    1982-01-01

    Deliberations and conclusions of a Workshop on Stable Isotopes and Derived Radioisotopes organized by the Subcommittee on Nuclear and Radiochemistry of the National Research Council's Committee on Chemical Sciences at the request of the Department of Energy (DOE) are summarized. The workshop was jointly supported by the National Institutes of Health and DOE's Office of Basic Energy Sciences. An overview with three recommendations resulting from the Workshop is followed by reports of the four Workshop panels. Background papers were prepared by individuals on the Steering Committee and made available to all participants prior to the Workshop. They are reproduced as Appendixes 3 to 8. Short reports on alternate separation techniques were presented at the Workshop and are reproduced in Appendixes 9 to 11.

  4. Laser-induced separation of hydrogen isotopes in the liquid phase

    DOEpatents

    Freund, Samuel M.; Maier, II, William B.; Beattie, Willard H.; Holland, Redus F.

    1980-01-01

    Hydrogen isotope separation is achieved by either (a) dissolving a hydrogen-bearing feedstock compound in a liquid solvent, or (b) liquefying a hydrogen-bearing feedstock compound, the liquid phase thus resulting being kept at a temperature at which spectral features of the feedstock relating to a particular hydrogen isotope are resolved, i.e., a clear-cut isotope shift is delineated, irradiating the liquid phase with monochromatic radiation of a wavelength which at least preferentially excites those molecules of the feedstock containing a first hydrogen isotope, inducing photochemical reaction in the excited molecules, and separating the reaction product containing the first isotope from the liquid phase.

  5. Isotope separation by selective charge conversion and field deflection

    DOEpatents

    Hickman, Robert G.

    1978-01-01

    A deuterium-tritium separation system wherein a source beam comprised of positively ionized deuterium (D.sup.+) and tritium (T.sup.+) is converted at different charge-exchange cell sections of the system to negatively ionized deuterium (D.sup.-) and tritium (T.sup.-). First, energy is added to the beam to accelerate the D.sup.+ ions to the velocity that is optimum for conversion of the D.sup.+ ions to D.sup.- ions in a charge-exchange cell. The T.sup.+ ions are accelerated at the same time, but not to the optimum velocity since they are heavier than the D.sup.+ ions. The T.sup.+ ions are, therefore, not converted to T.sup.- ions when the D.sup.+ ions are converted to D.sup.- ions. This enables effective separation of the beam by deflection of the isotopes with an electrostatic field, the D.sup.- ions being deflected in one direction and the T.sup.+ ions being deflected in the opposite direction. Next, more energy is added to the deflected beam of T.sup.+ ions to bring the T.sup.+ ions to the optimum velocity for their conversion to T.sup.- ions. In a particular use of the invention, the beams of D.sup.- and T.sup.- ions are separately further accelerated and then converted to energetic neutral particles for injection as fuel into a thermonuclear reactor. The reactor exhaust of D.sup.+ and T.sup.+ and the D.sup.+ and T.sup.+ that was not converted in the respective sections is combined with the source beam and recycled through the system to increase the efficiency of the system.

  6. Hydrogen isotope separation installation for the regeneration of tritium from gas mixtures in tritium facilities

    SciTech Connect

    Andrew, B.M.; Perevezentsev, A.N.; Selivanenko, I.L.

    1994-12-31

    The advantages and disadvantages of different methods for hydrogen isotope separation are considered in terms of their applicability for tritium regeneration in a tritium facility. Due to low inventory, simplicity of operation, flexibility, and safety the methods of separation using solid phases are preferable for tritium facility. The detail consideration of the separation processes with a solid phase reveals that highest efficiency of separation should be achieved in a counter-current separation column, which allow multiplying the thermodynamic isotopic effect. Because of difficulties of the organization of a solid phase motion in a separation column this method did not found practical application for separation of hydrogen isotopic mixtures. The main efforts of a few researches groups were devoted to improve the chromatographic separation process and equipment. The detail comparison of the separation in sectioned column with that in chromatographic as well as in cryodistillation columns show that counter-current separation in a sectioned column is more effective and has other advantages when middle throughput is required. Complete regeneration of an isotopic mixture with separation into three practically pure isotopes independently from isotopic composition of feed can be provided using two sectioned separation columns. Separation installation can operate continuously as well as periodically.

  7. System identification and trajectory optimization for guided store separation

    NASA Astrophysics Data System (ADS)

    Carter, Ryan E.

    Combat aircraft utilize expendable stores such as missiles, bombs, flares, and external tanks to execute their missions. Safe and acceptable separation of these stores from the parent aircraft is essential for meeting the mission objectives. In many cases, the employed missile or bomb includes an onboard guidance and control system to enable precise engagement of the selected target. Due to potential interference, the guidance and control system is usually not activated until the store is sufficiently far away from the aircraft. This delay may result in large perturbations from the desired flight attitude caused by separation transients, significantly reducing the effectiveness of the store and jeopardizing mission objectives. The purpose of this research is to investigate the use of a transitional control system to guide the store during separation. The transitional control system, or "store separation autopilot", explicitly accounts for the nonuniform flow field through characterization of the spatially variant aerodynamics of the store during separation. This approach can be used to mitigate aircraft-store interference and leverage aerodynamic interaction to improve separation characteristics. This investigation proceeds in three phases. First, system identification is used to determine a parametric model for the spatially variant aerodynamics. Second, the store separation problem is recast into a trajectory optimization problem, and optimal control theory is used to establish a framework for designing a suitable reference trajectory with explicit dependence on the spatially variant aerodynamics. Third, neighboring optimal control is used to construct a linear-optimal feedback controller for correcting deviations from the nominal reference trajectory due varying initial conditions, modeling errors, and flowfield perturbations. An extended case study based on actual wind tunnel and flight test measurements is used throughout to illustrate the effectiveness of the

  8. Liquid-phase thermal diffusion isotope separation apparatus and method having tapered column

    DOEpatents

    Rutherford, W.M.

    1985-12-04

    A thermal diffusion counterflow method and apparatus for separating isotopes in solution in which the solution is confined in a long, narrow, vertical slit which tapers from bottom to top. The variation in the width of the slit permits maintenance of a stable concentration distribution with relatively long columns, thus permitting isotopic separation superior to that obtained in the prior art.

  9. Liquid-phase thermal diffusion isotope separation apparatus and method having tapered column

    DOEpatents

    Rutherford, William M.

    1988-05-24

    A thermal diffusion counterflow method and apparatus for separating isotopes in solution in which the solution is confined in a long, narrow, vertical slit which tapers from bottom to top. The variation in the width of the slit permits maintenance of a stable concentration distribution with relatively long columns, thus permitting isotopic separation superior to that obtainable in the prior art.

  10. Method for separating different isotopes in compounds by means of laser radiation

    SciTech Connect

    Meyer-Kretschmer, G.; Jetter, H.; Toennies, P.

    1984-05-29

    A method is claimed for separating isotopes of a compound having molecules in the gaseous state which comprises exciting the gas with laser radiation having a frequency capable of exciting a selected isotope thereof, interacting the excited gas with electrons having an energy sufficient to form position ions therein and separating the ionized molecules from the other molecules in the gas.

  11. Optical spectroscopy using mass-separated beams: Nuclear properties of unstable indium and tin isotopes

    NASA Astrophysics Data System (ADS)

    Kuehl, T.; Kirchner, R.; Klepper, O.; Marx, D.; Dinger, U.; Eberz, J.; Huber, G.; Lochmann, H.; Menges, R.; Ulm, G.

    1987-05-01

    Collinear fast-beam laser-spectroscopy has been used to measure the hyperfine structure and isotope shift of several indium and tin isotopes. The related experimental techniques are described, including the preparation of mass-separated beams of neutron-deficient indium and tin isotopes at the GSI on-line mass separator following fusion-evaporation reactions. The deviation of the observed dependence of the charge radii upon the neutron number from the expected behaviour is briefly discussed.

  12. Highly Efficient Quantum Sieving in Porous Graphene-like Carbon Nitride for Light Isotopes Separation

    PubMed Central

    Qu, Yuanyuan; Li, Feng; Zhou, Hongcai; Zhao, Mingwen

    2016-01-01

    Light isotopes separation, such as 3He/4He, H2/D2, H2/T2, etc., is crucial for various advanced technologies including isotope labeling, nuclear weapons, cryogenics and power generation. However, their nearly identical chemical properties made the separation challenging. The low productivity of the present isotopes separation approaches hinders the relevant applications. An efficient membrane with high performance for isotopes separation is quite appealing. Based on first-principles calculations, we theoretically demonstrated that highly efficient light isotopes separation, such as 3He/4He, can be reached in a porous graphene-like carbon nitride material via quantum sieving effect. Under moderate tensile strain, the quantum sieving of the carbon nitride membrane can be effectively tuned in a continuous way, leading to a temperature window with high 3He/4He selectivity and permeance acceptable for efficient isotopes harvest in industrial application. This mechanism also holds for separation of other light isotopes, such as H2/D2, H2/T2. Such tunable quantum sieving opens a promising avenue for light isotopes separation for industrial application. PMID:26813491

  13. Highly Efficient Quantum Sieving in Porous Graphene-like Carbon Nitride for Light Isotopes Separation

    NASA Astrophysics Data System (ADS)

    Qu, Yuanyuan; Li, Feng; Zhou, Hongcai; Zhao, Mingwen

    2016-01-01

    Light isotopes separation, such as 3He/4He, H2/D2, H2/T2, etc., is crucial for various advanced technologies including isotope labeling, nuclear weapons, cryogenics and power generation. However, their nearly identical chemical properties made the separation challenging. The low productivity of the present isotopes separation approaches hinders the relevant applications. An efficient membrane with high performance for isotopes separation is quite appealing. Based on first-principles calculations, we theoretically demonstrated that highly efficient light isotopes separation, such as 3He/4He, can be reached in a porous graphene-like carbon nitride material via quantum sieving effect. Under moderate tensile strain, the quantum sieving of the carbon nitride membrane can be effectively tuned in a continuous way, leading to a temperature window with high 3He/4He selectivity and permeance acceptable for efficient isotopes harvest in industrial application. This mechanism also holds for separation of other light isotopes, such as H2/D2, H2/T2. Such tunable quantum sieving opens a promising avenue for light isotopes separation for industrial application.

  14. Isotope separation using tuned laser and electron beam

    NASA Technical Reports Server (NTRS)

    Trajmar, Sandor (Inventor)

    1987-01-01

    The apparatus comprises means for producing an atomic beam containing the isotope of interest and other isotopes. Means are provided for producing a magnetic field traversing the path of the atomic beam of an intensity sufficient to broaden the energy domain of the various individual magnetic sublevels of the isotope of interest and having the atomic beam passing therethrough. A laser beam is produced of a frequency and polarization selected to maximize the activation of only individual magnetic sublevels of the isotope of interest with the portion of its broadened energy domain most removed from other isotopes with the stream. The laser beam is directed so as to strike the atomic beam within the magnetic field and traverse the path of the atomic beam whereby only the isotope of interest is activated by the laser beam. The apparatus further includes means for producing a collimated and high intensity beam of electrons of narrow energy distribution within the magnetic field which is aimed so as to strike the atomic beam while the atomic beam is simultaneously struck by the laser beam and at an energy level selected to ionize the activated isotope of interest but not ground state species included therewith. Deflection means are disposed in the usual manner to collect the ions.

  15. 10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Illustrative List of Lithium Isotope Separation Facilities... Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's Export Licensing Authority a. Facilities or plants for the separation of lithium isotopes....

  16. 10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Illustrative List of Lithium Isotope Separation Facilities... Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's Export Licensing Authority a. Facilities or plants for the separation of lithium isotopes....

  17. Gravitational separation of gases and isotopes in polar ice caps.

    PubMed

    Craig, H; Horibe, Y; Sowers, T

    1988-12-23

    Atmospheric gases trapped in polar ice at the firn to ice transition layer are enriched in heavy isotopes (nitrogen-15 and oxygen-18) and in heavy gases (O(2)/N(2) and Ar/N(2) ratios) relative to the free atmosphere. The maximum enrichments observed follow patterns predicted for gravitational equilibrium at the base of the firn layer, as calculated from the depth to the transition layer and the temperature in the firn. Gas ratios exhibit both positive and negative enrichments relative to air: the negative enrichments of heavy gases are consistent with observed artifacts of vacuum stripping of gases from fractured ice and with the relative values of molecular diameters that govern capillary transport. These two models for isotopic and elemental fractionation provide a basis for understanding the initial enrichments of carbon-13 and oxygen-18 in trapped CO(2), CH(4), and O(2) in ice cores, which must be known in order to decipher ancient atmospheric isotopic ratios.

  18. LLNL medical and industrial laser isotope separation: large volume, low cost production through advanced laser technologies

    SciTech Connect

    Comaskey, B.; Scheibner, K. F.; Shaw, M.; Wilder, J.

    1998-09-02

    The goal of this LDRD project was to demonstrate the technical and economical feasibility of applying laser isotope separation technology to the commercial enrichment (>lkg/y) of stable isotopes. A successful demonstration would well position the laboratory to make a credible case for the creation of an ongoing medical and industrial isotope production and development program at LLNL. Such a program would establish LLNL as a center for advanced medical isotope production, successfully leveraging previous LLNL Research and Development hardware, facilities, and knowledge.

  19. Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

    NASA Astrophysics Data System (ADS)

    Watkins, James M.; DePaolo, Donald J.; Ryerson, Frederick J.; Peterson, Brook T.

    2011-06-01

    Molecular diffusion in natural volcanic liquids discriminates between isotopes of major ions (e.g., Fe, Mg, Ca, and Li). Although isotope separation by diffusion is expected on theoretical grounds, the dependence on mass is highly variable for different elements and in different media. Silicate liquid diffusion experiments using simple liquid compositions were carried out to further probe the compositional dependence of diffusive isotopic discrimination and its relationship to liquid structure. Two diffusion couples consisting of the mineral constituents anorthite (CaAl 2Si 2O 8; denoted AN), albite (NaAlSi 3O 8; denoted AB), and diopside (CaMgSi 2O 6; denoted DI) were held at 1450 °C for 2 h and then quenched to ambient pressure and temperature. Major-element as well as Ca and Mg isotope profiles were measured on the recovered quenched glasses. In both experiments, Ca diffuses rapidly with respect to Si. In the AB-AN experiment, D Ca/ D Si ≈ 20 and the efficiency of isotope separation for Ca is much greater than in natural liquid experiments where D Ca/ D Si ≈ 1. In the AB-DI experiment, D Ca/ D Si ≈ 6 and the efficiency of isotope separation is between that of the natural liquid experiments and the AB-AN experiment. In the AB-DI experiment, D Mg/ D Si ≈ 1 and the efficiency of isotope separation for Mg is smaller than it is for Ca yet similar to that observed for Mg in natural liquids. The results from the experiments reported here, in combination with results from natural volcanic liquids, show clearly that the efficiency of diffusive separation of Ca isotopes is systematically related to the solvent-normalized diffusivity - the ratio of the diffusivity of the cation ( D Ca) to the diffusivity of silicon ( D Si). The results on Ca isotopes are consistent with available data on Fe, Li, and Mg isotopes in silicate liquids, when considered in terms of the parameter D cation/ D Si. Cations diffusing in aqueous solutions display a similar relationship

  20. Stable isotope production in the former USSR by electromagnetic separation techniques

    NASA Astrophysics Data System (ADS)

    Kaschejev, N. A.; Polyakov, L. A.; Tunin, V. V.

    1993-09-01

    The present paper gives a brief review of the status of electromagnetic isotope separation techniques in the former USSR. It describes the basic specifications of the equipment as well as the general scheme of the production process, and considers questions relating to the chemical processing of isotopic material and analytical control techniques. Finally, a summary is given of the main separation data obtained during the last ten years, and the prospects of future development and of enhancing the economical effectiveness of isotope production are discussed.

  1. Pooled versus separate measurements of tree-ring stable isotopes.

    PubMed

    Dorado Liñán, Isabel; Gutiérrez, Emilia; Helle, Gerhard; Heinrich, Ingo; Andreu-Hayles, Laia; Planells, Octavi; Leuenberger, Markus; Bürger, Carmen; Schleser, Gerhard

    2011-05-01

    δ(13)C and δ(18)O of tree rings contain time integrated information about the environmental conditions weighted by seasonal growth dynamics and are well established as sources of palaeoclimatic and ecophysiological data. Annually resolved isotope chronologies are frequently produced by pooling dated growth rings from several trees prior to the isotopic analyses. This procedure has the advantage of saving time and resources, but precludes from defining the isotopic error or statistical uncertainty related to the inter-tree variability. Up to now only a few studies have compared isotope series from pooled tree rings with isotopic measurements from individual trees. We tested whether or not the δ(13)C and the δ(18)O chronologies derived from pooled and from individual tree rings display significant differences at two locations from the Iberian Peninsula to assess advantages and constraints of both methodologies. The comparisons along the period 1900-2003 reveal a good agreement between pooled chronologies and the two mean master series which were created by averaging raw individual values (Mean) or by generating a mass calibrated mean (MassC). In most of the cases, pooled chronologies show high synchronicity with averaged individual samples at interannual scale but some differences also show up especially when comparing δ(18)O decadal to multi-decadal variations. Moreover, differences in the first order autocorrelation among individuals may be obscured by pooling strategies. The lack of replication of pooled chronologies prevents detection of a bias due to a higher mass contribution of one sample but uncertainties associated with the analytical process itself, as sample inhomogeneity, seems to account for the observed differences.

  2. Separate visual representations for perception and for visually guided behavior

    NASA Technical Reports Server (NTRS)

    Bridgeman, Bruce

    1989-01-01

    Converging evidence from several sources indicates that two distinct representations of visual space mediate perception and visually guided behavior, respectively. The two maps of visual space follow different rules; spatial values in either one can be biased without affecting the other. Ordinarily the two maps give equivalent responses because both are veridically in register with the world; special techniques are required to pull them apart. One such technique is saccadic suppression: small target displacements during saccadic eye movements are not preceived, though the displacements can change eye movements or pointing to the target. A second way to separate cognitive and motor-oriented maps is with induced motion: a slowly moving frame will make a fixed target appear to drift in the opposite direction, while motor behavior toward the target is unchanged. The same result occurs with stroboscopic induced motion, where the frame jump abruptly and the target seems to jump in the opposite direction. A third method of separating cognitive and motor maps, requiring no motion of target, background or eye, is the Roelofs effect: a target surrounded by an off-center rectangular frame will appear to be off-center in the direction opposite the frame. Again the effect influences perception, but in half of the subjects it does not influence pointing to the target. This experience also reveals more characteristics of the maps and their interactions with one another, the motor map apparently has little or no memory, and must be fed from the biased cognitive map if an enforced delay occurs between stimulus presentation and motor response. In designing spatial displays, the results mean that what you see isn't necessarily what you get. Displays must be designed with either perception or visually guided behavior in mind.

  3. Isotopic Effect on Ion Mobility and Separation of Isotopomers by High-Field Ion Mobility Spectrometry

    SciTech Connect

    Shvartsburg, Alexandre A.; Clemmer, David E.; Smith, Richard D.

    2010-10-01

    Since early 1900-s, when vacuum techniques and ion detectors first enabled investigations of gas-phase ions, two approaches to their separation and characterization have emerged - mass spectrometry (MS) and ion mobility spectrometry (IMS).1,2 Though both exploit that distinct charged species move in electric fields differently, MS is performed in vacuum and is based only on the ion mass/charge (m/q) ratio while IMS involves sufficiently dense buffer gases and relies on ion transport properties. The first major discovery enabled by MS was the existence of isotopes by Thomson and Aston,3 and isotopic analyses have since been integral to MS. In particular, the preparative separation of U isotopes using Lawrence’s Calutron was the first industrial application of MS,4 and isotopic labeling is key to MS quantification methods. With IMS, the issue of isotopes was largely ignored as the resolving power (R) was generally too low for their separation. Here, we demonstrate that recently developed high-resolution differential IMS can separate isotopic molecular ions, including nominal isobars with different isotopic content and isotopomers. This capability may enable a new method for isotope separation in a small-scale format at ambient pressure and aid localization of labeled sites in various molecules. Perhaps most importantly, the isotopic shifts depend on the labeled atom position and thus may contain the kind of detailed structural information that is available in solution or solid state using tools such as NMR but has not generally been obtainable for gas-phase ions.

  4. Status of stable isotopes separation at the Electromagnetic Plants of the Russian Research Center, ``Kurchatov Institute''

    NASA Astrophysics Data System (ADS)

    Kouzmine, R. N.; Bondarenko, V. G.; Pigarov, Ju. D.; Staroverov, L. I.; Tchesnokov, V. M.

    1999-12-01

    The four chamber electromagnetic isotope separator was constructed at the Russian Research Center (RRC) "Kurchatov Institute" more than 50 years ago. During this period, the plant was used for the development of ion sources and separation technologies. Isotopes of over 40 different elements have been separated. About 20 years ago, the reconstruction of two chambers was completed. The homogeneous magnetic field in these chambers was replaced with a field which falls-off on the radius ( r) as 1/ r. After reconstruction, the dispersion was increased by a factor of four and the enrichment of the isotopes was increased considerably. Ion beam collection was also facilitated. Many highly enriched isotopes were produced in the new chambers, including Gd, Yb, Zn, Tl, Pd, and others. One of the important problems now, is the reduction of all aspects of production costs for isotopes. A project to perfect the ion-optic scheme (IOS) for two chambers was carried out with the expected result of a dispersion of 44 mm at 1% relative mass difference. As a result of the modified ion source, increased productivity of the separators is expected. Other areas of ion source development in progress include: development of "standard" ion sources for the separators with inhomogeneous fields, development of high-temperature sources for Pd isotopes, and development of an ion source with sputtering supply for Ir, Pt, and other elements.

  5. National uses and needs for separated stable isotopes in physics, chemistry, and geoscience research

    NASA Astrophysics Data System (ADS)

    Zisman, M. S.

    Present uses of separated stable isotopes in the fields of physics, chemistry, and the geosciences were surveyed to identify current supply problems and to determine future needs. Demand for separated isotopes remains strong, with 220 different nuclides having been used in the past three years. The largest needs, in terms of both quantity and variety of isotopes, are found in nuclear physics research. Current problems include a lack of availability of many nuclides, unsatisfactory enrichment of rare species, and prohibitively high costs for certain important isotopes. Demand for separated isotopes is expected to remain roughly at present levels, although a shift toward more requests for highly enriched rare isotopes is predicted. Use of neutron rich nuclides below A = 100 for producing exotic ion beams at various accelerators and use of transition metal nuclei for nuclear magnetic resonance spectroscopy are expected to expand. An increase in the need for calibration standards for techniques of radiological dating, such as Sm/Nd and Lu/Hf is predicted, but in relatively small quantities. Most members of the research community would be willing to pay considerably more than they do now to maintain adequate supplies of stable isotopes.

  6. National uses and needs for separated stable isotopes in physics, chemistry, and geoscience research

    SciTech Connect

    Zisman, M.S.

    1982-01-01

    Present uses of separated stable isotopes in the fields of physics, chemistry, and the geosciences have been surveyed to identify current supply problems and to determine future needs. Demand for separated isotopes remains strong, with 220 different nuclides having been used in the past three years. The largest needs, in terms of both quantity and variety of isotopes, are found in nuclear physics research. Current problems include a lack of availability of many nuclides, unsatisfactory enrichment of rare species, and prohibitively high costs for certain important isotopes. It is expected that demands for separated isotopes will remain roughly at present levels, although there will be a shift toward more requests for highly enriched rare isotopes. Significantly greater use will be made of neutron-rich nuclides below A = 100 for producing exotic ion beams at various accelerators. Use of transition metal nuclei for nuclear magnetic resonance spectroscopy will expand. In addition, calibration standards will be required for the newer techniques of radiological dating, such as the Sm/Nd and Lu/Hf methods, but in relatively small quantities. Most members of the research community would be willing to pay considerably more than they do now to maintain adequate supplies of stable isotopes.

  7. Electromagnetic separation of stable isotopes at the Institute of Atomic Energy, Academia Sinica

    NASA Astrophysics Data System (ADS)

    Ming-da, Hua; Gong-pan, Li; Shi-jun, Su; Nai-feng, Mao; Hung-yung, Lu

    1981-07-01

    For almost 20 years the Institute of Atomic Energy, Academia Sinica has been separating stable isotopes of the elements by electromagnetic separators and supplying these materials to research work in many fields of our country. In this article we shall attempt to outline the growth of the effort and describe the present situation.

  8. Nested reactor chamber and operation for Hg-196 isotope separation process

    DOEpatents

    Grossman, M.W.

    1991-10-08

    The present invention is directed to an apparatus for use in [sup 196]Hg separation and its method of operation. Specifically, the present invention is directed to a nested reactor chamber useful for [sup 196]Hg isotope separation reactions avoiding the photon starved condition commonly encountered in coaxial reactor systems. 6 figures.

  9. Nested reactor chamber and operation for Hg-196 isotope separation process

    DOEpatents

    Grossman, Mark W.

    1991-01-01

    The present invention is directed to an apparatus for use in .sup.196 Hg separation and its method of operation. Specifically, the present invention is directed to a nested reactor chamber useful for .sup.196 Hg isotope separation reactions avoiding the photon starved condition commonly encountered in coaxial reactor systems.

  10. tritium isotope separation by CO 2 laser-induced multiphoton dissociation of CTF 3

    NASA Astrophysics Data System (ADS)

    Makide, Yoshihiro; Hagiwara, Satoru; Tominaga, Takeshi; Takeuchi, Kazuo; Nakane, Ryohei

    1981-08-01

    Isotope separation of tritium at ppm concentration level was achieved by CO 2 laser-induced multiphoton dissociation of CTF 3 in CHF 3 with single-step separation factors exceeding 500. The effects of laser frequency, pulse energy, pulse duration, irradiation geometry, tritium concentration, sample pressure, and buffer gas were investigated.

  11. Separation of selected stable isotopes by liquid-phase thermal diffusion and by chemical exchange

    NASA Astrophysics Data System (ADS)

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

    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 S34, CL35, and CL37 in significant quantities (100 to 500 g/yr) at costs much lower than those associated with the electromagnetic (Calutron) process. The separation of the isotopes of bromine by LTD is now in progress and BR79 is being produced in relatively simple equivalent at a rate on the order of 0.5 g/day. The results of recent measurements show that the isotopes of Zn can be separated by LTD of zinc alkyls. The isotopes of calcium can be separated by LTD and by chemical exchange. The LTD process is based on the use of aqueous Ca(NO3)2 as a working fluid.

  12. Isotopic effect on ion mobility and separation of isotopomers by high-field ion mobility spectrometry.

    PubMed

    Shvartsburg, Alexandre A; Clemmer, David E; Smith, Richard D

    2010-10-01

    Distinguishing and separating isotopic molecular variants is important across many scientific fields. However, discerning such variants, especially those producing no net mass difference, has been challenging. For example, single-stage mass spectrometry is broadly employed to analyze isotopes but is blind to isotopic isomers (isotopomers) and, except at very high resolution, species of the same nominal mass (isobars). Here, we report separation of isotopic ions, including isotopomers and isobars, using ion mobility spectrometry (IMS), specifically, the field asymmetric waveform IMS (FAIMS). The effect is not based on the different reduced masses of ion-gas molecule pairs previously theorized to cause isotopic separations in conventional IMS, but appears related to the details of energetic ion-molecule collisions in strong electric fields. The observed separation qualitatively depends on the gas composition and may be improved using gas mixtures. Isotopic shifts depend on the position of the labeled site, which allows its localization and contains information about the ion geometry, potentially enabling a new approach to molecular structure characterization.

  13. Anisotropic alpha emission from on-line separated isotopes

    SciTech Connect

    Wouters, J.; Vandeplassche, D.; van Walle, E.; Severijns, N.; Vanneste, L.

    1986-05-05

    A systematic on-line nuclear-orientation study of heavy isotopes using anisotropic ..cap alpha.. emission is reported for the first time. The anisotrophies recorded for /sup 199/At, /sup 201/At, and /sup 203/At are remarkably pronounced and strongly varying. At lower neutron number the ..cap alpha.. particles are more preferentially emitted perpendicularly to the nuclear-spin direction. This may be interpreted in terms of the high sensitivity of the ..cap alpha..-emission probability to changes in the nuclear shape.

  14. Photo-induced cataphoretic isotope separation. Final report, June 15, 1976-June 15, 1981

    SciTech Connect

    Carruthers, J A

    1981-03-01

    The original studies were undertaken to study the feasibility of radiation-induced cataphoretic separation. This part of the work is concerned with laser-induced cataphoretic separation in neon using a He-Ne 6328A laser. The basic concept of radiation-induced caphoretic isotope separation is based on the preferential excitation of one isotope with the result that one isotope is more readily ionized, and relatively more of its ions move toward the cathode in the dc discharge. For the later part of the work a second radiation source was added, a helical Ne/sup 20/ radiation lamp. Radiation-induced cataphoretic isotope separation has not been observed. Selective excitation has been achieved by both the He-Ne/sup 20/ 6328A laser and the Ne/sup 20/ helical radiation lamp in spite of the fact that the isotope shift is comprable with Doppler-broadened linewidths. Collisional excitation exchange between the Ne/sup 20/ and Ne/sup 22/ atoms does not appear to be a problem for the neon partial pressure range involved. The population of the 3S/sub 2/ and 2p/sub 4/ laser levels (6328A) are apparently too low to offer reasonable expectation of inducing observable cataphoretic isotope separation by means of the 6328A laser radiation, even with the high detection sensitivity of the scanning Fabry-Perot spectrometer sytem. The use of the additional radiation source in the form of a helical Ne/sup 20/ radiation lamp has not improved the effectiveness of the laser 6328A laser. It has become clear from these experiments, however, that for isotope separation in neon it is well to concentrate on using radiation sources that interact mainly with the ls population.

  15. Parasitic production of slow RI-beam from a projectile fragment separator by ion guide Laser Ion Source (PALIS)

    NASA Astrophysics Data System (ADS)

    Sonoda, Tetsu

    2009-10-01

    The projectile fragment separator BigRIPS of RIBF at RIKEN provides a wide variety of short-lived radioactive isotope (RI) ions without restrictions on their lifetime or chemical properties. A universal slow RI-beam facility (SLOWRI) to decelerate the beams from BigRIPS using an RF-carpet ion guide has been proposed as a principal facility of RIBF. However, beam time at such a modern accelerator facility is always limited and operational costs are high. We therefore propose an additional scheme as a complementary option to SLOWRI to drastically enhance the usability of such an expensive facility. In BigRIPS, a single primary beam produces thousands of isotopes but only one isotope is used for an experiment while the other >99.99% of isotopes are simply dumped in the slits or elsewhere in the fragment separator. We plan to locate a compact gas cell with 1 bar Ar at the slits. The thermalized ions in the cell will be quickly neutralized and transported to the exit by gas flow and resonantly re-ionized by lasers. Such low energy RI-beams will always be provided without any restriction to the main experiment. It will allow us to run parasitic experiments for precision atomic or decay spectroscopy, mass measurements. Furthermore, the resonance ionization in the cell itself can be used for high-sensitive laser spectroscopy, which will expand our knowledge of the ground state property of unstable nuclei.

  16. Separation and Analysis of Boron Isotope in High Plant by Thermal Ionization Mass Spectrometry

    PubMed Central

    Xu, Qingcai; Dong, Yuliang; Zhu, Huayu; Sun, Aide

    2015-01-01

    Knowledge of boron and its isotope in plants is useful to better understand the transposition and translocation of boron within plant, the geochemical behavior in the interface between soil and plant, and the biogeochemical cycle of boron. It is critical to develop a useful method to separate boron from the plant for the geochemical application of boron and its isotope. A method was developed for the extraction of boron in plant sample, whose isotope was determined by thermal ionization mass spectrometry. The results indicated that this method of dry ashing coupled with two-step ion-exchange chromatography is powerful for the separation of boron in plant sample with large amounts of organic matters completely. The ratios of boron isotope composition in those plant tissue samples ranged from −19.45‰ to +28.13‰ (total range: 47.58‰) with a mean value of 2.61 ± 11.76‰ SD. The stem and root isotopic compositions were lower than those in flower and leaf. The molecular mechanism of boron isotope may be responsible for the observed variation of boron isotopic composition and are considered as a useful tool for the better understanding of boron cycling process in the environment and for the signature of living systems. PMID:26819618

  17. Isotope separation and advanced manufacturing technology. Volume 2, No. 2, Semiannual report, April--September 1993

    SciTech Connect

    Kan, Tehmanu; Carpenter, J.

    1993-12-31

    This is the second issue of a semiannual report for the Isotope Separation and Advanced Manufacturing (ISAM) Technology Program at Lawrence Livermore National Laboratory. Primary objectives of the ISAM Program include: the Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) process, and advanced manufacturing technologies which include industrial laser materials processing and new manufacturing technologies for uranium, plutonium, and other strategically important materials in support of DOE and other national applications. Topics included in this issue are: production plant product system conceptual design, development and operation of a solid-state switch for thyratron replacement, high-performance optical components for high average power laser systems, use of diode laser absorption spectroscopy for control of uranium vaporization rates, a two-dimensional time dependent hydrodynamical ion extraction model, and design of a formaldehyde photodissociation process for carbon and oxygen isotope separation.

  18. Electromagnetic Separation of Isotopes at Oak Ridge: An informal account of history, techniques, and accomplishments.

    PubMed

    Love, L O

    1973-10-26

    In 1960 I attended a European conference on isotope separation, after which I visited the Niels Bohr Institute in Copenhagen. A staff member there ventured the opinion that the separation of isotopes will be first on the list of important contributions to the peaceful uses of the atom when the Atomic Energy Commission's memoirs are written in the year 2000. In 1968 the AEC Division of Research contracted with the National Research Council of the National Academy of Sciences to conduct a review of the AEC program for the separation of stable isotopes by electromagnetic and thermal diffusion methods. This ad hoc panel comprised seven scientists from the fields of chemistry, classical physics, geochemistry, geophysics, medicine, and physics. In their final report on national uses and needs for separated stable isotopes (9), they referred to the store of separated isotopes as a "real national asset that attains increasing value as science and technology develop" and recommended "continuation of the program as a national resource of great value to the United States." Later, in a discussion of this report with A. M. Weinberg, J. Koch, himself a pioneer in electromagnetic isotope separation and member of the Danish Atomic Energy Program, said he would correct the statement that the Oak Ridge electromagnetic facility is a "national asset" to read "international asset." From my narrow viewpoint after an extended and complete engrossment with this program for so many years, it is gratifying to learn that such men as those mentioned above share my belief that the work has indeed been worthwhile.

  19. Separative analyses of a chromatographic column packed with a core-shell adsorbent for lithium isotope separation

    SciTech Connect

    Sugiyama, T.; Sugura, K.; Enokida, Y.; Yamamoto, I.

    2015-03-15

    Lithium-6 is used as a blanket material for sufficient tritium production in DT fueled fusion reactors. A core-shell type adsorbent was proposed for lithium isotope separation by chromatography. The mass transfer model in a chromatographic column consisted of 4 steps, such as convection and dispersion in the column, transfer through liquid films, intra-particle diffusion and and adsorption or desorption at the local adsorption sites. A model was developed and concentration profiles and time variation in the column were numerically simulated. It became clear that core-shell type adsorbents with thin porous shell were saturated rapidly relatively to fully porous one and established a sharp edge of adsorption band. This is very important feature because lithium isotope separation requires long-distance development of adsorption band. The values of HETP (Height Equivalent of a Theoretical Plate) for core-shell adsorbent packed column were estimated by statistical moments of the step response curve. The value of HETP decreased with the thickness of the porous shell. A core-shell type adsorbent is, then, useful for lithium isotope separation. (authors)

  20. A Model of Isotope Separation in Cells at the Early Stages of Evolution.

    PubMed

    Melkikh, A V; Bokunyaeva, A O

    2016-03-01

    The separation of the isotopes of certain ions can serve as an important criterion for the presence of life in the early stages of its evolution. A model of the separation of isotopes during their transport through the cell membrane is constructed. The dependence of the selection coefficient on various parameters is found. In particular, it is shown that the maximum efficiency of the transport of ions corresponds to the minimum enrichment coefficient. At the maximum enrichment, the efficiency of the transport system approaches ½. Calculated enrichment coefficients are compared with experimentally obtained values for different types of cells, and the comparison shows a qualitative agreement between these quantities.

  1. Multi-purpose hydrogen isotopes separation plant design

    SciTech Connect

    Boniface, H.A.; Gnanapragasam, N.V.; Ryland, D.K.; Suppiah, S.; Castillo, I.

    2015-03-15

    There is a potential interest at AECL's Chalk River Laboratories to remove tritium from moderately tritiated light water and to reclaim tritiated, downgraded heavy water. With only a few limitations, a single CECE (Combined Electrolysis and Catalytic Exchange) process configuration can be designed to remove tritium from heavy water or light water and upgrade heavy water. Such a design would have some restrictions on the nature of the feed-stock and tritium product, but could produce essentially tritium-free light or heavy water that is chemically pure. The extracted tritium is produced as a small quantity of tritiated heavy water. The overall plant capacity is fixed by the total amount of electrolysis and volume of catalyst. In this proposal, with 60 kA of electrolysis a throughput of 15 kg*h{sup -1} light water for detritiation, about 4 kg*h{sup -1} of heavy water for detritiation and about 27 kg*h{sup -1} of 98% heavy water for upgrading can be processed. Such a plant requires about 1,000 liters of AECL isotope exchange catalyst. The general design features and details of this multi-purpose CECE process are described in this paper, based on some practical choices of design criteria. In addition, we outline the small differences that must be accommodated and some compromises that must be made to make the plant capable of such flexible operation. (authors)

  2. Anisotropic. cap alpha. -emission of on-line separated isotopes

    SciTech Connect

    Wouters, J.; Vandeplassche, D.; van Walle, E.; Severijns, N.; Van Haverbeke, J.; Vanneste, L.

    1987-12-10

    The technical realization of particle detection at very low temperatures (4K) has made it possible to study for the first time the anisotropic ..cap alpha..-decay of oriented nuclei which have been produced, separated and implanted on line. The measured ..cap alpha..-angular distributions reveal surprising new results on nuclear aspects as well as in solid state physics. The nuclear structure information from these data questions the older ..cap alpha..-decay theoretical interpretation and urges for a reaxamination of the earliest work on anisotropic ..cap alpha..-decay.

  3. Investigation related to hydrogen isotopes separation by cryogenic distillation

    SciTech Connect

    Bornea, A.; Zamfirache, M.; Stefanescu, I.; Preda, A.; Balteanu, O.; Stefan, I.

    2008-07-15

    Research conducted in the last fifty years has shown that one of the most efficient techniques of removing tritium from the heavy water used as moderator and coolant in CANDU reactors (as that operated at Cernavoda (Romania)) is hydrogen cryogenic distillation. Designing and implementing the concept of cryogenic distillation columns require experiments to be conducted as well as computer simulations. Particularly, computer simulations are of great importance when designing and evaluating the performances of a column or a series of columns. Experimental data collected from laboratory work will be used as input for computer simulations run at larger scale (for The Pilot Plant for Tritium and Deuterium Separation) in order to increase the confidence in the simulated results. Studies carried out were focused on the following: - Quantitative analyses of important parameters such as the number of theoretical plates, inlet area, reflux flow, flow-rates extraction, working pressure, etc. - Columns connected in series in such a way to fulfil the separation requirements. Experiments were carried out on a laboratory-scale installation to investigate the performance of contact elements with continuous packing. The packing was manufactured in our institute. (authors)

  4. A status of progress for the Laser Isotope Separation (LIS) process

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1976-01-01

    An overview of the Laser Isotope Separation (LIS) methodology is given together with illustrations showing a simplified version of the LIS technique, an example of the two-photon photoionization category, and a diagram depicting how the energy levels of various isotope influence the LIS process. Applications were proposed for the LIS system which, in addition to enriching uranium, could in themselves develop into programs of tremendous scope and breadth. These include the treatment of radioactive wastes from light-water nuclear reactors, enriching the deuterium isotope to make heavy-water, and enriching the light isotopes of such elements as titanium for aerospace weight-reducing programs. Economic comparisons of the LIS methodology with the current method of gaseous diffusion indicate an overwhelming advantage; the laser process promises to be 1000 times more efficient. The technique could also be utilized in chemical reactions with the tuned laser serving as a universal catalyst to determine the speed and direction of a chemical reaction.

  5. Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

    SciTech Connect

    Watkins, J.M.; DePaolo, D.J.; Ryerson, F.J.; Peterson, B.

    2011-03-01

    Molecular diffusion in natural volcanic liquids discriminates between isotopes of major ions (e.g., Fe, Mg, Ca, and Li). Although isotope separation by diffusion is expected on theoretical grounds, the dependence on mass is highly variable for different elements and in different media. Silicate liquid diffusion experiments using simple liquid compositions were carried out to further probe the compositional dependence of diffusive isotopic discrimination and its relationship to liquid structure. Two diffusion couples consisting of the mineral constituents anorthite (CaAl{sub 2}Si{sub 2}O{sub 8}; denoted AN), albite (NaAlSi{sub 3}O{sub 8}; denoted AB), and diopside (CaMgSi{sub 2}O{sub 6}; denoted DI) were held at 1450°C for 2 h and then quenched to ambient pressure and temperature. Major-element as well as Ca and Mg isotope profiles were measured on the recovered quenched glasses. In both experiments, Ca diffuses rapidly with respect to Si. In the AB–AN experiment, D{sub Ca}/D{sub Si} ~ 20 and the efficiency of isotope separation for Ca is much greater than in natural liquid experiments where D{sub Ca}/D{sub Si} ~ 1. In the AB–DI experiment, D{sub Ca}/D{sub Si} ~ 6 and the efficiency of isotope separation is between that of the natural liquid experiments and the AB–AN experiment. In the AB–DI experiment, D{sub Mg}/D{sub Si} ~ 1 and the efficiency of isotope separation for Mg is smaller than it is for Ca yet similar to that observed for Mg in natural liquids. The results from the experiments reported here, in combination with results from natural volcanic liquids, show clearly that the efficiency of diffusive separation of Ca isotopes is systematically related to the solvent-normalized diffusivity—the ratio of the diffusivity of the cation (D{sub Ca}) to the diffusivity of silicon (D{sub Si}). The results on Ca isotopes are consistent with available data on Fe, Li, and Mg isotopes in silicate liquids, when considered in terms of the parameter D{sub cation

  6. A Low Temperature Distillation System for Separating Mixtures of Protium, Deuterium, and Tritium Isotopes

    SciTech Connect

    Embury, Michael, C.; Watkins, Reed A.; Hinckley, Richard; Post, Jr., Arthur H.

    1985-04-30

    A low temperature (24 K) distillation system for separating mixtures of hydrogen isotopes has been designed, fabricated, and delivered for use as the main component of the Hydrogen Isotope Separation System (HISS) at Mound. The HISS will handle feed mixtures of all six isotopic species of hydrogen (H2, HD, HT, D2, DT, T2) and will enrich the tritium while producing a stackable raffinate. Arther D. Little, Inc. (ADL) was the prime contractor for the distillation system. The design and fabrication techniques used for the HISS distillation system are similar to those used for previous stills which were also designed and built by ADL. The distillation system was tested with mixtures of protium and deuterium at the ADL shop. This system, as well as the feed, product, and raffinate handling systems are presently being installed at Mound where integrated testing is scheduled next calendar year.

  7. Installations for separation of hydrogen isotopes by the method of chemical isotopic exchange in the `water-hydrogen` system

    SciTech Connect

    Andreev, B.M.; Sakharovsky, Y.A.; Rozenkevich, M.B.; Magomedbekov, E.P.; Park, Y.S.; Uborskiy, V.V.; Trenin, V.D.; Alekseev, I.A.; Fedorchenko, O.A.; Karpov, S.P.; Konoplev, K.A.

    1995-10-01

    The paper presents the results of more than a year of running a pilot setup for separation of hydrogen isotopes using catalytic isotopic exchange between hydrogen and liquid water. The setup is 5 m high, has the inner diameter of 28 mm, and is equipped with upper and lower reflux devices. The experimental values of HETP vary from 15 cm at T=333 K to 38 cm at T=293 K. The setup is capable of upgrading diluted heavy water with 85-90% deuterium content up to [D{sub 2}O] > 99.95 at.%, yielding daily 4 kg of the product. We also report on the progress in constructing a similar setup for eliminating tritium and an industrial setup, for which the one reported is a prototype. 10 refs., 1 fig., 3 tabs.

  8. Experimental Confirmation of Isotope Fractionation in Thiomolybdates Using Ion Chromatographic Separation and Detection by Multicollector ICPMS.

    PubMed

    Kerl, Carolin F; Lohmayer, Regina; Bura-Nakić, Elvira; Vance, Derek; Planer-Friedrich, Britta

    2017-03-07

    Molybdenum (98)Mo/(95)Mo isotope ratios are a sediment paleo proxy for the redox state of the ancient ocean. Under sulfidic conditions, no fractionation between seawater and sediment should be observed if molybdate (MoO4(2-)) is quantitatively transformed to tetrathiomolybdate (MoS4(2-)) and precipitated. However, quantum mechanical calculations previously suggested that incomplete sulfidation could be associated with substantial fractionation. To experimentally confirm isotope fractionation in thiomolybdates, a new approach for determination of isotope ratios of individual thiomolybdate species was developed that uses chromatography (HPLC-UV) to separate individual thiomolybdates, collecting each peak and analyzing isotope ratios with multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). Using commercially available MoO4(2-) and MoS4(2-) standards, the method was evaluated and excellent reproducibility and accuracy were obtained. For species with longer retention times, complete chromatographic peaks had to be collected to avoid isotope fractionation within peaks. Isotope fractionation during formation of thiomolybdates could be experimentally proven for the first time in the reaction of MoO4(2-) with 20-fold or 50-fold excess of sulfide. The previously calculated isotope fractionation for MoS4(2-) was confirmed, and the result for MoO2S2(2-) was in the predicted range. Isotopic fractionation during MoS4(2-) transformation with pressurized air was dominated by kinetic fractionation. Further optimization and online-coupling of the HPLC-MC-ICPMS approach for determination of low concentrations in natural samples will greatly help to obtain more accurate species-selective isotope information.

  9. The effect of small scale variablity in isotopic composition of precipitation on hydrograph separation results

    NASA Astrophysics Data System (ADS)

    Fischer, Benjamin; van Meerveld, Ilja; Seibert, Jan

    2016-04-01

    Understanding runoff processes is important for predictions of streamflow quantity and quality. The two-component isotope hydrograph separation (IHS) method is a valuable tool to study how catchments transform rainfall into runoff. IHS allows the stormflow hydrograph to be separated into rainfall (event water) and water that was stored in the catchment before the event (pre-event water). To be able to perform an IHS, water samples of baseflow (pre-event water) and stormflow are collected at the stream outlet. Rainfall is usually collected at one location by hand as an event total or sampled sequentially during the event. It is usually assumed that the spatial variability in rainfall and the isotopic composition of rainfall are negligible for small (<10km2) catchments. However, different studies have shown that precipitation can vary within short distances. Subsequently it remains unclear how the spatio-temproal variability of rainfall and the stable isotope composition of rainfall affect the results of an IHS. In this study, we investigated the effects of the spatio-temporal variability in the isotopic composition of rainfall across a small headwater catchment in Switzerland. Rainfall was measured at eight locations and three streams (catchment area of 0.15, 0.23, and 0.7 km2). The isotopic composition of rainfall and streamflow were sampled for 10 different rain events (P: 5 mm intervals, Q: 12 to 51 samples per events). This dataset was used to perform a two-component isotope hydrograph separation. The results show that for some events the spatial variability in total rainfall, mean and maximum rainfall intensity and stable isotope composition of rainfall was high. There was no relation between the stable isotope composition of rainfall and the rainfall sum, rainfall intensity or altitude. The spatial variability of the isotopic composition of rainfall was for 4 out of the 10 events as large as the temporal variability in the isotopic composition. Different

  10. Separation of copper, iron, and zinc from complex aqueous solutions for isotopic measurement

    USGS Publications Warehouse

    Borrok, D.M.; Wanty, R.B.; Ridley, W.I.; Wolf, R.; Lamothe, P.J.; Adams, M.

    2007-01-01

    The measurement of Cu, Fe, and Zn isotopes in natural samples may provide valuable information about biogeochemical processes in the environment. However, the widespread application of stable Cu, Fe, and Zn isotope chemistry to natural water systems remains limited by our ability to efficiently separate these trace elements from the greater concentrations of matrix elements. In this study, we present a new method for the isolation of Cu, Fe, and Zn from complex aqueous solutions using a single anion-exchange column with hydrochloric acid media. Using this method we are able to quantitatively separate Cu, Fe, and Zn from each other and from matrix elements in a single column elution. Elution of the elements of interest, as well as all other elements, through the anion-exchange column is a function of the speciation of each element in the various concentrations of HCl. We highlight the column chemistry by comparing our observations with published studies that have investigated the speciation of Cu, Fe, and Zn in chloride solutions. The functionality of the column procedure was tested by measuring Cu, Fe, and Zn isotopes in a variety of stream water samples impacted by acid mine drainage. The accuracy and precision of Zn isotopic measurements was tested by doping Zn-free stream water with the Zn isotopic standard. The reproducibility of the entire column separation process and the overall precision of the isotopic measurements were also evaluated. The isotopic results demonstrate that the Cu, Fe, and Zn column separates from the tested stream waters are of sufficient purity to be analyzed directly using a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS), and that the measurements are fully-reproducible, accurate, and precise. Although limited in scope, these isotopic measurements reveal significant variations in ??65Cu (- 1.41 to + 0.30???), ??56Fe (- 0.56 to + 0.34???), and ??66Zn (0.31 to 0.49???) among samples collected from different

  11. 10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., Plants and Equipment Under NRC's Export Licensing Authority N Appendix N to Part 110 Energy NUCLEAR... Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's Export Licensing Authority a. Facilities or plants for the separation of lithium isotopes....

  12. 10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., Plants and Equipment Under NRC's Export Licensing Authority N Appendix N to Part 110 Energy NUCLEAR... Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's Export Licensing Authority a. Facilities or plants for the separation of lithium isotopes....

  13. 10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Plants and Equipment Under NRC's Export Licensing Authority N Appendix N to Part 110 Energy NUCLEAR... Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's Export Licensing Authority a. Facilities or plants for the separation of lithium isotopes....

  14. Neutron Spectral Brightness of Cold Guide 4 at the High Flux Isotope Reactor

    NASA Astrophysics Data System (ADS)

    Winn, B. L.; Robertson, J. L.; Iverson, E. B.; Selby, D. L.

    2010-11-01

    The High Flux Isotope Reactor resumed operation in June of 2007 with a supercritical hydrogen cold source in horizontal beam tube 4. Cold guide 4 is a guide system designed to deliver neutrons from this source with a reasonable flux at wavelengths greater than 4 Å to several instruments, and includes a 15-m, 96-section, 4-channel bender. A time-of-flight spectrum with calibrated detector was recorded at port C of cold guide 4, and compared to McStas simulations, to generate a brightness spectrum.

  15. CO2-laser isotope separation of tritium with pentafluoroethane-T (C2TF5)

    NASA Astrophysics Data System (ADS)

    Makide, Y.; Kato, S.; Tominaga, T.; Takeuchi, K.

    1982-08-01

    Isotope separation of tritium by CO2 laser-induced multiphoton dissociation (MPD) of C2TF5 is reported for the first time. The MPD spectrum obtained for C2TF5 comprised a broad peak at about 940 cm-1 where C2HF5 was nearly transparent. The unimolecular dissociation of C2TF5 was induced with much lower laser fluence than that for CTF3, another working molecule we proposed for laser isotope separation of tritium. The mechanisms and kinetics of the dissociation of C2TF5 and C2HF5 were investigated under various experimental conditions: laser frequency, pulse energy, pulse duration, tritium concentration, sample pressure, buffer gas pressure and irradiation geometry. Single-step separation factors exceeding 500 were achieved with the most efficient P(20) line in 00o 10o0 transition at 944.2 cm-1.

  16. Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis

    USGS Publications Warehouse

    Ball, J.W.; Bassett, R.L.

    2000-01-01

    A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

  17. IRiS—Exploring new frontiers in neutron-rich isotopes of the heaviest elements with a new Inelastic Reaction Isotope Separator

    NASA Astrophysics Data System (ADS)

    Dvorak, J.; Block, M.; Düllmann, Ch. E.; Heinz, S.; Herzberg, R.-D.; Schädel, M.

    2011-10-01

    A dedicated Inelastic Reaction Isotope Separator (IRiS) for multi-nucleon transfer products will be designed and installed at GSI. Research at IRiS will focus on the investigation of new neutron-rich isotopes of the heaviest elements, study of which will advance various research fields, such as nuclear chemistry, nuclear and atomic physics, as well as nuclear astrophysics. The scientific motivation for this project and the alternative design options for the separator and its main components are discussed.

  18. Implications of Plutonium isotopic separation on closed fuel cycles and repository design

    SciTech Connect

    Forsberg, C.

    2013-07-01

    Advances in laser enrichment may enable relatively low-cost plutonium isotopic separation. This would have large impacts on LWR closed fuel cycles and waste management. If Pu-240 is removed before recycling plutonium as mixed oxide (MOX) fuel, it would dramatically reduce the buildup of higher plutonium isotopes, Americium, and Curium. Pu-240 is a fertile material and thus can be replaced by U-238. Eliminating the higher plutonium isotopes in MOX fuel increases the Doppler feedback, simplifies reactor control, and allows infinite recycle of MOX plutonium in LWRs. Eliminating fertile Pu-240 and Pu-242 reduces the plutonium content in MOX fuel and simplifies fabrication. Reducing production of Pu-241 reduces production of Am-241 - the primary heat generator in spent nuclear fuels after several decades. Reducing heat generating Am-241 would reduce repository cost and waste toxicity. Avoiding Am- 241 avoids its decay product Np-237, a nuclide that partly controls long-term oxidizing repository performance. Most of these benefits also apply to LWR plutonium recycled into fast reactors. There are benefits for plutonium isotopic separation in fast reactor fuel cycles (particularly removal of Pu-242) but the benefits are less. (author)

  19. Development of phase-separated scintillators with light-guiding properties.

    PubMed

    Yasui, Nobuhiro; Ohashi, Yoshihiro; Kobayashi, Tamaki; Den, Tohru

    2012-10-23

    Alkali halide systems that function as phase-separated scintillators (PSSs) with light-guiding properties are sucessfully created. Furthermore, it is the matrix phases of the PSSs which display the light-guiding properties. CsI-NaCl:Tl is a practical material pair because of its high pixel light output and good spatial resolution.

  20. Integral Engine Inlet Particle Separator. Volume 2. Design Guide

    DTIC Science & Technology

    1975-08-01

    herein will be used in the design of integral inlet particle separators for future Army aircraft gas turbine engines . Apprupriate technical personnel...OF INTEGRAL GAS TURBINE ENGINE SOLID PARTICLE INLET SEPARATORS, PHASE I, FEASIBILITY STUDY AND DESIGN, Pratt and Whitney Aircraft ; USAAVLABS Technical...USAAVLABS Technical Report 70-36, U.S. Army Aviation Materiel Laboratories, Fort Eustis, Virginia, August 1970 AD 876 584. 13. ENGINES , AIRCRAFT

  1. Aspects regarding at 13C isotope separation column control using Petri nets system

    NASA Astrophysics Data System (ADS)

    Boca, M. L.; Ciortea, M. E.

    2015-11-01

    This paper is intended to show that Petri nets can be also applicable in the chemical industry. It used linear programming, modeling underlying Petri nets, especially discrete event systems for isotopic separation, the purpose of considering and control events in real-time through graphical representations. In this paper it is simulate the control of 13C Isotope Separation column using Petri nets. The major problem with 13C comes from the difficulty of obtaining it and raising its natural fraction. Carbon isotopes can be obtained using many methods, one of them being the cryogenic distillation of carbon monoxide. Some few aspects regarding operating conditions and the construction of such cryogenic plants are known today, and even less information are available as far as the separation process modeling and control are concerned. In fact, the efficient control of the carbon monoxide distillation process represents a necessity for large-scale 13C production. Referring to a classic distillation process, some models for carbon isotope separation have been proposed, some based on mass, component and energy balance equations, some on the nonlinear wave theory or the Cohen equations. For modeling the system it was used Petri nets because in this case it is deal with discrete event systems. In use of the non-timed and with auxiliary times Petri model, the transport stream was divided into sections and these sections will be analyzed successively. Because of the complexity of the system and the large amount of calculations required it was not possible to analyze the system as a unitary whole. A first attempt to model the system as a unitary whole led to the blocking of the model during simulation, because of the large processing times.

  2. Hydrogen isotope systematics of phase separation in submarine hydrothermal systems: Experimental calibration and theoretical models

    USGS Publications Warehouse

    Berndt, M.E.; Seal, R.R.; Shanks, Wayne C.; Seyfried, W.E.

    1996-01-01

    Hydrogen isotope fractionation factors were measured for coexisting brines and vapors formed by phase separation of NaCl/H2O fluids at temperatures ranging from 399-450??C and pressures from 277-397 bars. It was found that brines are depleted in D compared to coexisting vapors at all conditions studied. The magnitude of hydrogen isotope fractionation is dependent on the relative amounts of Cl in the two phases and can be empirically correlated to pressure using the following relationship: 1000 ln ??(vap-brine) = 2.54(??0.83) + 2.87(??0.69) x log (??P), where ??(vap-brine) is the fractionation factor and ??P is a pressure term representing distance from the critical curve in the NaCl/H2O system. The effect of phase separation on hydrogen isotope distribution in subseafloor hydrothermal systems depends on a number of factors, including whether phase separation is induced by heating at depth or by decompression of hydrothermal fluids ascending to the seafloor. Phase separation in most subseafloor systems appears to be a simple process driven by heating of seawater to conditions within the two-phase region, followed by segregation and entrainment of brine or vapor into a seawater dominated system. Resulting vent fluids exhibit large ranges in Cl concentration with no measurable effect on ??D. Possible exceptions to this include hydrothermal fluids venting at Axial and 9??N on the East Pacific Rise. High ??D values of low Cl fluids venting at Axial are consistent with phase separation taking place at relatively shallow levels in the oceanic crust while negative ??D values in some low Cl fluids venting at 9??N suggest involvement of a magmatic fluid component or phase separation of D-depleted brines derived during previous hydrothermal activity.

  3. Separation of calcium-48 isotope by crown ether chromatography using ethanol/hydrochloric acid mixed solvent.

    PubMed

    Okumura, Shin; Umehara, Saori; Fujii, Yasuhiko; Nomura, Masao; Kaneshiki, Toshitaka; Ozawa, Masaki; Kishimoto, Tadafumi

    2015-10-09

    Benzo-18-crown-6 ether resin embedded in porous silica beads was synthesized and used as the packing material for chromatographic separation of (48)Ca isotope. The aim of the present work is to develop efficient isotope enrichment process for double β decay nuclide (48)Ca. To this end, ethanol/HCl mixed solvent was selected as the medium for the chromatographic separation. Adsorption of calcium on the resin was studied at different HCl concentrations and different ethanol mixing ratios in batch-wise experiments. A very interesting phenomenon was observed; Ca adsorption is controlled not by the overall HCl concentration of the mixed solvent, but by the initial concentration of added HCl solution. Calcium break-through chromatography experiments were conducted by using 75v/v% ethanol/25v/v% 8M HCl mixed solvent at different flow rates. The isotope separation coefficient between (48)Ca and (40)Ca was determined as 3.8×10(-3), which is larger than that of pure HCl solution system. Discussion is extended to the chromatographic HETP, height equivalent to a theoretical plate.

  4. A Mass Spectrometry Study of Isotope Separation in the Laser Plume

    NASA Astrophysics Data System (ADS)

    Suen, Timothy Wu

    Accurate quantification of isotope ratios is critical for both preventing the development of illicit weapons programs in nuclear safeguards and identifying the source of smuggled material in nuclear forensics. While isotope analysis has traditionally been performed by mass spectrometry, the need for in situ measurements has prompted the development of optical techniques, such as laser-induced breakdown spectroscopy (LIBS) and laser ablation molecular isotopic spectrometry (LAMIS). These optical measurements rely on laser ablation for direct solid sampling, but several past studies have suggested that the distribution of isotopes in the ablation plume is not uniform. This study seeks to characterize isotope separation in the laser plume through the use of orthogonal-acceleration time-of-flight mass spectrometry. A silver foil was ablated with a Nd:YAG at 355 nm at an energy of 50 muJ with a spot size of 71 mum, for a fluence of 1.3 J/cm2 and an irradiance of 250 MW/cm2. Flat-plate repellers were used to sample the plume, and a temporal profile of the ions was obtained by varying the time delay on the high-voltage pulse. A spatial profile along the axis of the plume was generated by changing the position of the sample, which yielded snapshots of the isotopic composition with time. In addition, the reflectron time-of-flight system was used as an energy filter in conjunction with the repellers to sample slices of the laser plasma orthogonal to the plume axis. Mass spectrometry of the plume revealed a fast ion distribution and a slow ion distribution. Measurements taken across the entire plume showed the fast 109Ag ions slightly ahead in both space and time, causing the 107Ag fraction to drop to 0.34 at 3 mus, 4 mm from the sample surface. Although measurements centered on the near side of the plume did not show isotope separation, the slow ions on the far side of the plume included much more 109Ag than 107Ag. In addition to examining the isotope content of the ablation

  5. Preparative separation of underivatized amino acids for compound-specific stable isotope analysis and radiocarbon dating of hydrolyzed bone collagen.

    PubMed

    Tripp, Jennifer A; McCullagh, James S O; Hedges, Robert E M

    2006-01-01

    Analysis of stable and radioactive isotopes from bone collagen provides useful information to archaeologists about the origin and age of bone artifacts. Isolation and analysis of single amino acids from the proteins can provide additional and more accurate information by removing contamination and separating a bulk isotope signal into its constituent parts. In this paper, we report a new method for the separation and isolation of underivatized amino acids from bone collagen, and their analysis by isotope ratio MS and accelerator MS. RP chromatography is used to separate the amino acids with nonpolar side chains, followed by an ion pair separation to isolate the remaining amino acids. The method produces single amino acids with little or no contamination from the separation process and allows for the measurement of accurate stable isotope ratios and pure samples for radiocarbon dating.

  6. DEMONSTRATION OF THE NEXT-GENERATION TCAP HYDROGEN ISOTOPE SEPARATION PROCESS

    SciTech Connect

    Heung, L; Henry Sessions, H; Steve Xiao, S; Heather Mentzer, H

    2009-01-09

    The first generation of TCAP hydrogen isotope separation process has been in service for tritium separation at the Savannah River Site since 1994. To prepare for replacement, a next-generation TCAP process has been developed. This new process simplifies the column design and reduces the equipment requirements of the thermal cycling system. An experimental twelve-meter column was fabricated and installed in the laboratory to demonstrate its performance. This new design and its initial test results were presented at the 8th International Conference on Tritium Science and Technology and published in the proceedings. We have since completed the startup and demonstration the separation of protium and deuterium in the experimental unit. The unit has been operated for more than 200 cycles. A feed of 25% deuterium in protium was separated into two streams each better than 99.7% purity.

  7. Stormflow-hydrograph separation based on isotopes: the thrill is gone--what's next?

    USGS Publications Warehouse

    Burns, Douglas A.

    2002-01-01

    Beginning in the 1970s, the promise of a new method for separatingstormflow hydrographs using18O,2H, and3Hprovedanirresistibletemptation, and was a vast improvement over graphical separationand solute tracer methods that were prevalent at the time. Eventu-ally, hydrologists realized that this new method entailed a plethoraof assumptions about temporal and spatial homogeneity of isotopiccomposition (many of which were commonly violated). Nevertheless,hydrologists forged ahead with dozens of isotope-based hydrograph-separation studies that were published in the 1970s and 1980s.Hortonian overland flow was presumed dead. By the late 1980s,the new isotope-based hydrograph separation technique had movedinto adolescence, accompanied by typical adolescent problems suchas confusion and a search for identity. As experienced hydrologistscontinued to use the isotope technique to study stormflow hydrol-ogy in forested catchments in humid climates, their younger peersfollowed obligingly—again and again. Was Hortonian overland flowreally dead and forgotten, though? What about catchments in whichpeople live and work? And what about catchments in dry climatesand the tropics? How useful were study results when several of theassumptions about the homogeneity of source waters were commonlyviolated? What if two components could not explain the variation ofisotopic composition measured in the stream during stormflow? Andwhat about uncertainty? As with many new tools, once the initialshine wore off, the limitations of the method became a concern—oneof which was that isotope-based hydrograph separations alone couldnot reveal much about the flow paths by which water arrives at astream channel during storms.

  8. 80ℏk momentum separation with Bloch oscillations in an optically guided atom interferometer

    NASA Astrophysics Data System (ADS)

    McDonald, G. D.; Kuhn, C. C. N.; Bennetts, S.; Debs, J. E.; Hardman, K. S.; Johnsson, M.; Close, J. D.; Robins, N. P.

    2013-11-01

    We demonstrate phase sensitivity in a horizontally guided, acceleration-sensitive atom interferometer with a momentum separation of 80ℏk between its arms. A fringe visibility of 7% is observed. Our coherent pulse sequence accelerates the cold cloud in an optical waveguide, an inherently scalable route to large momentum separation and high sensitivity. We maintain coherence at high momentum separation due to both the transverse confinement provided by the guide and our use of optical δ-kick cooling on our cold-atom cloud. We also construct a horizontal interferometric gradiometer to measure the longitudinal curvature of our optical waveguide.

  9. Separation Of Uranium And Plutonium Isotopes For Measurement By Multi Collector Inductively Coupled Plasma Mass Spectroscopy

    SciTech Connect

    Martinelli, R E; Hamilton, T F; Williams, R W; Kehl, S R

    2009-03-29

    Uranium (U) and plutonium (Pu) isotopes in coral soils, contaminated by nuclear weapons testing in the northern Marshall Islands, were isolated by ion-exchange chromatography and analyzed by mass spectrometry. The soil samples were spiked with {sup 233}U and {sup 242}Pu tracers, dissolved in minerals acids, and U and Pu isotopes isolated and purified on commercially available ion-exchange columns. The ion-exchange technique employed a TEVA{reg_sign} column coupled to a UTEVA{reg_sign} column. U and Pu isotope fractions were then further isolated using separate elution schemes, and the purified fractions containing U and Pu isotopes analyzed sequentially using multi-collector inductively coupled plasma mass spectrometer (MCICP-MS). High precision measurements of {sup 234}U/{sup 235}U, {sup 238}U/{sup 235}U, {sup 236}U/{sup 235}U, and {sup 240}Pu/{sup 239}Pu in soil samples were attained using the described methodology and instrumentation, and provide a basis for conducting more detailed assessments of the behavior and transfer of uranium and plutonium in the environment.

  10. Isotopic determinations of rhenium and osmium in meteorites by using fusion, distillation and ion-exchange separations

    USGS Publications Warehouse

    Morgan, J.W.; Walker, R.J.

    1989-01-01

    A stable isotope-dilution method using resonance ionization mass spectrometry is suitable for the determination of rhenium and osmium abundances and osmium isotopic composition in carbonaceous chondrites and iron meteorites. The chemical procedure involves sodium peroxide fusion, followed by distillation of osmium from sulfuric acid/hydrogen peroxide and subsequent anion-exchange separation of rhenium from the same solution. ?? 1989.

  11. Modelling aspects regarding the control in 13C isotope separation column

    NASA Astrophysics Data System (ADS)

    Boca, M. L.

    2016-08-01

    Carbon represents the fourth most abundant chemical element in the world, having two stable and one radioactive isotope. The 13Carbon isotopes, with a natural abundance of 1.1%, plays an important role in numerous applications, such as the study of human metabolism changes, molecular structure studies, non-invasive respiratory tests, Alzheimer tests, air pollution and global warming effects on plants [9] A manufacturing control system manages the internal logistics in a production system and determines the routings of product instances, the assignment of workers and components, the starting of the processes on not-yet-finished product instances. Manufacturing control does not control the manufacturing processes themselves, but has to cope with the consequences of the processing results (e.g. the routing of products to a repair station). In this research it was fulfilled some UML (Unified Modelling Language) diagrams for modelling the C13 Isotope Separation column, implement in STARUML program. Being a critical process and needing a good control and supervising, the critical parameters in the column, temperature and pressure was control using some PLC (Programmable logic controller) and it was made some graphic analyze for this to observe some critical situation than can affect the separation process. The main parameters that need to be control are: -The liquid nitrogen (N2) level in the condenser. -The electrical power supplied to the boiler. -The vacuum pressure.

  12. Photon Scattering from the Stable Even-Mass Mo Isotopes Below the Neutron-Separation Energy

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Hutcheson, A.; Kwan, E.; Tonchev, A. P.; Tornow, W.; Angell, C.; Hammond, S.; Karwowski, H. J.; Kelley, J. H.; Schwengner, R.; Dönau, F.; Wagner, A.

    2008-10-01

    We present results from photon-scattering experiments on the stable even-mass molybdenum isotopes below the neutron-separation energy carried out with bremsstrahlung at the superconducting electron accelerator ELBE at the Research Center Dresden-Rossendorf in Germany, and with monoenergetic photon beams at the HIγS facility at TUNL. We applied statistical methods in order to correct for the branching and cascade transitions and to determine the photoabsorption cross section. The obtained results allowed us to extend the tail of the Giant Dipole Resonance below the (,) threshold down to 4 MeV. The photoabsorption cross sections deduced from the present experiments show that the dipole strength increases with the neutron number of the Mo isotopes. The experimental results are discussed in the frame of Quasiparticle-Random-Phase-Approximation in a deformed basis which describe the increasing strength as a result of the deformation.

  13. Extraction, separation, and intramolecular carbon isotope characterization of athabasca oil sands acids in environmental samples.

    PubMed

    Ahad, Jason M E; Pakdel, Hooshang; Savard, Martine M; Simard, Marie-Christine; Smirnoff, Anna

    2012-12-04

    Here we report a novel approach to extract, isolate, and characterize high molecular weight organic acids found in the Athabasca oil sands region using preparative capillary gas chromatography (PCGC) followed by thermal conversion/elemental analysis-isotope ratio mass spectrometry (TC/EA-IRMS). A number of different "naphthenic acids" surrogate standards were analyzed as were samples from the bitumen-rich unprocessed McMurray Formation, oil sands process water, groundwater from monitoring wells, and surface water from the Athabasca River. The intramolecular carbon isotope signature generated by online pyrolysis (δ(13)C(pyr)) showed little variation (±0.6‰) within any given sample across a large range of mass fractions separated by PCGC. Oil sand, tailings ponds, and deep McMurray Formation groundwater were significantly heavier (up to ∼9‰) compared to surface water and shallow groundwater samples, demonstrating the potential use of this technique in source apportionment studies.

  14. Highly effective hydrogen isotope separation in nanoporous metal-organic frameworks with open metal sites: direct measurement and theoretical analysis.

    PubMed

    Oh, Hyunchul; Savchenko, Ievgeniia; Mavrandonakis, Andreas; Heine, Thomas; Hirscher, Michael

    2014-01-28

    Separating gaseous mixtures that consist of very similar size is one of the critical issues in modern separation technology. Especially, the separation of the isotopes hydrogen and deuterium requires special efforts, even though these isotopes show a very large mass ratio. Conventionally, H/D separation can be realized through cryogenic distillation of the molecular species or the Girdler-sulfide process, which are among the most energy-intensive separation techniques in the chemical industry. However, costs can be significantly reduced by using highly mass-selective nanoporous sorbents. Here, we describe a hydrogen isotope separation strategy exploiting the strongly attractive open metal sites present in nanoporous metal-organic frameworks of the CPO-27 family (also referred to as MOF-74). A theoretical analysis predicts an outstanding hydrogen isotopologue separation at open metal sites due to isotopal effects, which has been directly observed through cryogenic thermal desorption spectroscopy. For H2/D2 separation of an equimolar mixture at 60 K, the selectivity of 12 is the highest value ever measured, and this methodology shows extremely high separation efficiencies even above 77 K. Our theoretical results imply also a high selectivity for HD/H2 separation at similar temperatures, and together with catalytically active sites, we propose a mechanism to produce D2 from HD/H2 mixtures with natural or enriched deuterium content.

  15. Nitrogen Isotopes in Olivine Separates from Volcanic Arcs, Hot Spots and Continental Mantle Xenoliths

    NASA Astrophysics Data System (ADS)

    Fischer, T. P.; Takahata, N.; Sano, Y.; Hilton, D. R.

    2004-12-01

    We report the first nitrogen isotopic data of olivine separates from volcanic arcs (Cerro Negro, Nicaragua; Izalco, El Salvador; Turrialba, Costa Rica; Ichinomegata, Japan). In addition, we report nitrogen isotopic data of olivine separates from ocean islands (Hawaii, Reunion, Iceland) and continental mantle xenoliths (San Carlos, Arizona). Samples were processed by crushing and analyzed using a modified noble gas mass spectrometer (VG3400). N concentrations range from 0.6 to 22 micro ccSTP/g olivine. The 15N/14N ratios (expressed in the δ 15N notation where δ 15N sample = {[(15N/14N)sample/(15N/14N)Air]-1} X 1000) of olivine separates are distinctly different from air (0.0‰ ) and range from lower than mean MORB (- 5 ‰ ) to values characteristic of (subducted) oceanic sediments (+ 7 ‰ ). Positive δ 15N values are found in olivines from volcanic arcs: Cerro Negro 1992 ash (+ 6.2 ± 1.6‰ ), Izalco lava flow (+ 5.1 ± 0.7‰ ), Ichinomengata spinel lherzolite (+ 1.1 ± 0.5 ‰ ) with the exception of Turrialba lava (- 1.7 ± 2.5‰ ). Olivines from hot spots have both positive and negative δ 15N signatures: Iceland, Theistareykir - northern rift zone (- 8± 1.6 ‰ ), Hawaii, dunite from 1801 Kaupulehu flow of Hualuai volcano (+ 3.1 ± 0.3 ‰ ) and Reunion dunite (+ 0.2 ± 0.5‰ ). The San Carlos mantle xenolith has a value of - 1.5 ± 2.5‰ . 40Ar/36Ar ratios of the samples as determined in this study or reported in the literature are significantly higher than air (295.5) in olivines from Ichinomegata, San Carlos, Iceland, Reunion and Hawaii. The olivines from Cerro Negro have a 40Ar/36Ar ratio of 306, close to that of air. The 3He/4He ratios of the samples are higher than the MORB value of 8.0 RA (RA is the 3He/4He of air), the exception being Cerro Negro (6.1 RA). Hawaii, Reunion and Iceland have 3He/4He of 10.3, 12.9 and 12.3 RA, respectively. δ 15N signatures of fumarole gas samples collected at Cerro Negro (+ 4.9 ±0.1 ‰ ), Turrialba (- 1.0 ±0

  16. RAPID SEPARATION METHOD FOR 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES

    SciTech Connect

    Maxwell, S.; Culligan, B.; Noyes, G.

    2010-07-26

    A new rapid method for the determination of {sup 237}Np and Pu isotopes in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for large soil samples. The new soil method utilizes an acid leaching method, iron/titanium hydroxide precipitation, a lanthanum fluoride soil matrix removal step, and a rapid column separation process with TEVA Resin. The large soil matrix is removed easily and rapidly using this two simple precipitations with high chemical recoveries and effective removal of interferences. Vacuum box technology and rapid flow rates are used to reduce analytical time.

  17. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    DOE PAGES

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  18. Laser enhanced microwave plasma isotope separation. Final report, September 30, 1992--September 29, 1995

    SciTech Connect

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

    1996-06-01

    The experimental research was to focus on laser excitation of a low abundance isotope and then ionize and separate the isotope of low abundance using a microwave/ECR discharge at 2.45 GHz. A small compact electron cyclotron resonance ion source, which uses permanent magnets, was constructed during this project. The dye laser was purchased and later an excimer laser had to also be purchased because it turned out that the dye laser could not be pumped by our copper laser. It was intended that the dye laser be tuned to a wavelength of 670.8 nm, which would excite {sup 6}Li which would then be preferentially ionized by the ECR source and collected with a charged grid. The degree of enrichment was to be determined using thermal ionization mass spectrometry. The final objective of this project was to assess the feasibility of this system to large-scale production of stable isotopes. However the funding of this project was interrupted and we were not able to achieve all of our goals.

  19. Analogy between mission critical detection in distributed systems and 13C isotope separation column

    NASA Astrophysics Data System (ADS)

    Boca, Maria L.; Secara, Mihai

    2015-02-01

    Carbon represents the fourth most abundant chemical element in the world, having two stable and one radioactive isotope. The 13 Carbon isotopes, with a natural abundance of 1.1%, plays an important role in numerous applications, such as the study of human metabolism changes, molecular structure studies, non-invasive respiratory tests, Alzheimer tests, air pollution and global warming effects on plants [2]. Distributed systems are increasingly being applied in critical real-time applications and their complexity forces programmers to use design methods which guarantee correctness and increase the maintainability of the products. Objectoriented methodologies are widely used to cope with complexity in any kind of system, but most of them lack a formal foundation to allow the analysis and verification of designs, which is one of the main requirements for dealing with concurrent and reactive systems. This research is intended to make an analogy between two tips of industrial processes, one 13C Isotope Separation Column and other one distributed systems. We try to highlight detection of "mission critical "situations for this two processes and show with one is more critical and needs deeply supervisyon [1], [3].

  20. Rapid U separation and its precise isotopic measurements using ICP-QMS

    NASA Astrophysics Data System (ADS)

    Douville, E.; Salle, E.; Gourgiotis, A.; Ayrault, S.; Frank, N.

    2007-12-01

    Here we present a largely simplified analytical separation technique for U from marin carbonates and sediments and U isotopic measurements obtained by inductively coupled plasma-source quadrupole mass spectrometer (ICP-QMS) Xseries II - Thermo Scientific. The separation of U is done from dissolved carbonates and sediments using a single ion exchange column packed with ~500 μg of UTEVA resin from EICHROM industries. The column is pre-cleaned and loaded by several rinses of MilliQ water and 3N HNO3. Then earth alkali, transition metals and lanthanides are eluted quantitatively using 3N HNO3. Pure Th and U solutions are then successively extracted from the column using 3N HCl and 1N HCl at ~100% yield. U solutions at ~25-50 ppb were injected into the ICP-QMS at conventional sample flow rates of approximately 1ml/minute, without particular injection systems such as a desolvator or μ - nebuliser. 30 scans with 180 sweeps and a dwell time of 50 ms per isotope were used to collect 233U, 234U, 235U and 236U on an electron multiplier. Baseline sensitivity was followed on mass 228 with <1cps at ~ 1000cps on mass 234. Then, mass discrimination was corrected using the 233U/236U spike of known isotopic ratio and HU1 reference solutions were used to test the reproducibility and to correct drifts using standard - sample bracketing. Overall ICPMS analyses yield a stunning reproducibility of <0.4 % at 2 σ, which is close to the one obtained by conventional TIMS instruments ~0.2-0.4 %. We have applied this technique to organic rich sediments and marine carbonate samples previously measured by TIMS and found a perfect agreement for both U concentration and its isotopic composition. This rapid and effective chemical purification and isotopic measurement of U allows to process more than 20 samples a day allowing to investigate large numbers of natural samples for weathering, tracer and geochronological studies.

  1. Methods for the separation of rhenium, osmium and molybdenum applicable to isotope geochemistry

    USGS Publications Warehouse

    Morgan, J.W.; Golightly, D.W.; Dorrzapf, A.F.

    1991-01-01

    Effective methods are described for the chemical separation of rhenium, osmium and molybdenum. The methods are based on distillation and anion-exchange chromatography, and have been the basis for rhenium-osmium isotope studies of ore deposits and meteorites. Successful anion-exchange separation of osmium requires both recognition and careful control of the osmium species in solution; thus, distillation of osmium tetroxide from a mixture of sulfuric acid and hydrogen peroxide is preferred to anion-exchange. Distribution coefficients measured for perrhenate in sulfuric acid media are sufficiently high (Kd > 500) for rhenium to be directly loaded onto an ion-exchange column from a distillation residue and subsequently eluted with nitric acid. Polymerization of molybdenum species during elution is prevented by use of a solution that is 1M in hydrochloric acid and 1M in sodium chloride. ?? 1991.

  2. Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

    SciTech Connect

    Xiao, X.; Kit Heung, L.; Sessions, H.T.

    2015-03-15

    TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

  3. Recent great impact by an Isotope Separator On-Line (ISOL) in nuclear and radiochemistry.

    PubMed

    Sakama, Minoru

    2016-01-01

    On April 9 2015, the Letter article titled "Measurement of the first ionization potential of lawrencium, element 103" is now published at News and Views on Nature (2015) which has been performed by our remarkably Japanese colleagues of nuclear and radiochemistry at JAEA (Japan Atomic Energy Agency). In this review, the author will state that the isotope separator on-line (ISOL) our regularly used, one of mass separation techniques, with a thermal surface ionization makes possible for determining the ionization potential of lawrencium based on the fruitful fundations of developing the ISOL system until now and also ever studying searches for unknown nuclei and these nuclear decay properties around actinide region in the past 20 years.

  4. GRPAUT: a program for Pu isotopic analysis (a user's guide). ISPO task A. 76

    SciTech Connect

    Fleissner, J G

    1981-01-30

    GRPAUT is a modular program for performing automated Pu isotopic analysis supplied to the International Atomic Energy Agency (IAEA) per ISPO Task A.76. Section I of this user's guide for GRPAUT presents an overview of the various programs and disk files that are used in performing a Pu isotopic analysis. Section II describes the program GRFEDT which is used in creating and editing the analysis parameter file that contains all the spectroscopic information needed at runtime by GRPAUT. An example of the dialog and output of GRFEDT is shown in Appendix B. Section III describes the operation of the various GRPAUT modules: GRPNL2, the peak stripping module; EFFCH2, the efficiency calculation module; and ISOAUT, the isotopic calculation module. (A description of the peak fitting methodology employed by GRPNL2 is presented in Appendix A.) Finally, Section IV outlines the procedure for determining the peak shape constants for a detector system and describes the operation of the program used to create and edit the peak shape parameter files. An output of GRPAUT, showing an example of a complete isotopic analysis, is presented in Appendix C. Source listings of all the Fortran programs supplied to the Agency under ISPO Task A.76 are contained in Appendix E.

  5. Stable hydrogen isotopic analysis of nanomolar molecular hydrogen by automatic multi-step gas chromatographic separation.

    PubMed

    Komatsu, Daisuke D; Tsunogai, Urumu; Kamimura, Kanae; Konno, Uta; Ishimura, Toyoho; Nakagawa, Fumiko

    2011-11-15

    We have developed a new automated analytical system that employs a continuous flow isotope ratio mass spectrometer to determine the stable hydrogen isotopic composition (δD) of nanomolar quantities of molecular hydrogen (H(2)) in an air sample. This method improves previous methods to attain simpler and lower-cost analyses, especially by avoiding the use of expensive or special devices, such as a Toepler pump, a cryogenic refrigerator, and a special evacuation system to keep the temperature of a coolant under reduced pressure. Instead, the system allows H(2) purification from the air matrix via automatic multi-step gas chromatographic separation using the coolants of both liquid nitrogen (77 K) and liquid nitrogen + ethanol (158 K) under 1 atm pressure. The analytical precision of the δD determination using the developed method was better than 4‰ for >5 nmol injections (250 mL STP for 500 ppbv air sample) and better than 15‰ for 1 nmol injections, regardless of the δD value, within 1 h for one sample analysis. Using the developed system, the δD values of H(2) can be quantified for atmospheric samples as well as samples of representative sources and sinks including those containing small quantities of H(2) , such as H(2) in soil pores or aqueous environments, for which there is currently little δD data available. As an example of such trace H(2) analyses, we report here the isotope fractionations during H(2) uptake by soils in a static chamber. The δD values of H(2) in these H(2)-depleted environments can be useful in constraining the budgets of atmospheric H(2) by applying an isotope mass balance model.

  6. Isotopic separation of He-3/He-4 from solar wind gases evolved from the lunar regolith

    NASA Astrophysics Data System (ADS)

    Wilkes, William R.; Wittenberg, Layton J.

    The potential benefits of He-3 when utilized in a nuclear fusion reactor to provide clean, safe electricity in the 21st century for the world's inhabitants has been documented. Unfortunately, He is scarce on earth. Large quantities of He-3, perhaps a million tons, are embedded in the lunar regolith, presumably implanted by the solar wind together with other elements, notably He-4, H, C, and N. Several studies have suggested processing the lunar regolith and recovering these valuable solar wind gases. Once released, these gases can be separated for use. The separation of helium isotopes is described in this paper. He-3 constitutes only 400 at. ppm of lunar He, too dilute to separate economically by distillation alone. A 'superfluid' separator is being considered to preconcentrate the He-3. The superfluid separator consists of a porous filter in a tube maintained at a temperature of 2.17 K or less. Although the He-4, which is superfluid below 2.17 K, flows readily through the filter, the He is blocked by the filter, and becomes enriched at the feed end. He can be enriched to about 10 percent in such a system. The enriched product from the superfluid separation serves as a feed to a distillation apparatus operating at a pressure of 9 kPa, with a boiler temperature of 2.4 K, and a condenser temperature of 1.6 K. Under constant flow conditions, a 99.9 percent enriched He product can be produced in this apparatus. The heat rejection load of the refrigeration equipment necessary to cool the separation operations would be conducted during the lunar nights.

  7. A Two-Week Guided Inquiry Protein Separation and Detection Experiment for Undergraduate Biochemistry

    ERIC Educational Resources Information Center

    Carolan, James P.; Nolta, Kathleen V.

    2016-01-01

    A laboratory experiment for teaching protein separation and detection in an undergraduate biochemistry laboratory course is described. This experiment, performed in two, 4 h laboratory periods, incorporates guided inquiry principles to introduce students to the concepts behind and difficulties of protein purification. After using size-exclusion…

  8. Comparison of methods for separating small quantities of hydrogen isotopes from an inert gas

    SciTech Connect

    Willms, R.S.; Tuggle, D.; Birdsell, S.; Parkinson, J.; Price, B.; Lohmeir, D.

    1998-03-01

    It is frequent within tritium processing systems that a small amount of hydrogen isotopes (Q{sub 2}) must be separated from an inert gas such as He, Ar and N{sub 2}. Thus, a study of presently available technologies for effecting such a separation was performed. A base case and seven technology alternatives were identified and a simple design of each was prepared. These technologies included oxidation-adsorption-metal bed reduction, oxidation-adsorption-palladium membrane reactor, cryogenic adsorption, cryogenic trapping, cryogenic distillation, hollow fiber membranes, gettering and permeators. It was found that all but the last two methods were unattractive for recovering Q{sub 2} from N{sub 2}. Reasons for technology rejection included (1) the method unnecessarily turns the hydrogen isotopes into water, resulting in a cumbersome and more hazardous operation, (2) the method would not work without further processing, and (3) while the method would work, it would only do so in an impractical way. On the other hand, getters and permeators were found to be attractive methods for this application. Both of these methods would perform the separation in a straightforward, essentially zero-waste, single step operation. The only drawback for permeators was that limited low-partial Q{sub 2} pressure data is available. The drawbacks for getters are their susceptibility to irreversible and exothermic reaction with common species such as oxygen and water, and the lack of long-term operation of such beds. More research is envisioned for both of these methods to mature these attractive technologies.

  9. Breakthrough curve analysis of pressure swing adsorption for hydrogen isotope separation

    SciTech Connect

    Kotoh, K.; Tanaka, M.; Sakamoto, T.; Nakamura, Y.; Asakura, Y.; Uda, T.; Sugiyama, T.

    2008-07-15

    For the purpose of developing an effective system for hydrogen isotope separation, we have been studying the adsorption-desorption dynamic behavior of hydrogen and deuterium in a packed-bed column with synthetic zeolites, aimed at applying the pressure swing adsorption process. The adsorption behavior of molecules in the packed-bed is reflected in the breakthrough curves. To understand the characteristic behaviors of hydrogen isotopes in the packed-bed, we carried out breakthrough experiments in a conventional adsorption process and in a practical process following sequential processes alternating between adsorption and desorption. From the former experiments, the results were obtained that the overall mass transfer was influenced by longitudinal dispersion relating to the superficial velocity and that the process governing the mass transfer within adsorbents was diffusion in the macro-pores of pellets. In the latter experiments, unique profile breakthrough curves were observed. These curves can be described with the numerical simulation assuming the initial distributions in a packed-bed. (authors)

  10. New triple oxygen isotope data of bulk and separated fractions from SNC meteorites: Evidence for mantle homogeneity of Mars

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Jabeen, Iffat; Gregory, David; Verish, Robert; Banerjee, Neil R.

    2016-05-01

    We report precise triple oxygen isotope data of bulk materials and separated fractions of several Shergotty-Nakhla-Chassigny (SNC) meteorites using enhanced laser-assisted fluorination technique. This study shows that SNCs have remarkably identical Δ17O and a narrow range in δ18O values suggesting that these meteorites have assimilated negligibly small surface materials (<5%), which is undetectable in the oxygen isotope compositions reported here. Also, fractionation factors in coexisting silicate mineral pairs (px-ol and mask-ol) further demonstrate isotopic equilibrium at magmatic temperatures. We present a mass-dependent fractionation line for bulk materials with a slope of 0.526 ± 0.016 (1SE) comparable to the slope obtained in an earlier study (0.526 ± 0.013; Franchi et al. 1999). We also present a new Martian fractionation line for SNCs constructed from separated fractions (i.e., pyroxene, olivine, and maskelynite) with a slope of 0.532 ± 0.009 (1SE). The identical fractionation lines run above and parallel to our terrestrial fractionation line with Δ17O = 0.318 ± 0.016‰ (SD) for bulk materials and 0.316 ± 0.009‰ (SD) for separated fractions. The conformity in slopes and Δ17O between bulk materials and separated fractions confirm oxygen isotope homogeneity in the Martian mantle though recent studies suggest that the Martian lithosphere may potentially have multiple oxygen isotope reservoirs.

  11. Identification of new astatine isotopes using the gas-filled magnetic separator, Sassy

    SciTech Connect

    Yashita, S.

    1983-01-01

    A He-filled on-line separator system was built at the SuperHILAC and used to study the fusion products in the reaction /sup 56/Fe + /sup 141/Pr. The new neutron-deficient isotopes /sup 194/At and /sup 195/At were produced in this bombardment as three- and two-neutron-out products, respectively, and were identified by the ..cap alpha..-..cap alpha.. time-correlation technique. The measured ..cap alpha.. energies and half lives are 7.20 +/- 0.02 MeV and 180 +/- 80 msec for /sup 194/At, and 7.12 +/- 0.02 MeV and 200 +/- 100 msec for /sup 195/At.

  12. Identification of new astatine isotopes using the gas-filled magnetic separator, SASSY

    SciTech Connect

    Yashita, S.

    1984-02-01

    A He-filled on-line mass separator system was built at the SuperHILAC and used to study the fusion products in the reaction /sup 56/Fe + /sup 141/Pr. The new neutron-deficient isotopes /sup 194/At and /sup 195/At were produced in this bombardment as three- and two- neutron-out products, respectively, and were identified by the ..cap alpha..-..cap alpha.. time-correlation technique. The measured ..cap alpha.. energies and half lives are 7.20 +- 0.02 MeV and 180 +- 80 msec for /sup 194/At, and 7.12 +- 0.02 MeV and 200 +- 100 msec for /sup 195/At. 66 references.

  13. New Half-lives of r-process Zn and Ga Isotopes Measured with Electromagnetic Separation

    SciTech Connect

    Madurga, M; Surman, Rebecca; Borzov, Ivan N; Grzywacz, R.; Rykaczewski, Krzysztof Piotr; Gross, Carl J; Miller, D; Stracener, Daniel W; Batchelder, Jon Charles; Brewer, N.T.; Cartegni, L.; Hamilton, J. H.; Hwang, J. K.; Liu, S. H.; Ilyushkin, S.; Karny, M.; Korgul, A.; Krolas, W.; Kuzniak, A.; Mazzocchi, C.; Mendez, II, Anthony J; Miernik, K.; Padgett, Stephen; Paulauskas, S.; Ramayya, A. V.; Winger, J. A.; Wolinska-Cichocka, Marzena; Zganjar, E. F.

    2012-01-01

    The {beta} decays of neutron-rich nuclei near the doubly magic {sup 78}Ni were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of {sup 82}Zn (228 {+-} 10 ms), {sup 83}Zn (117 {+-} 20 ms), and {sup 85}Ga (93 {+-} 7 ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations. A new calculation was developed using the density functional model, which properly reproduced the new experimental values. The robustness of the new model in the {sup 78}Ni region allowed us to extrapolate data for more neutron-rich isotopes. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A > 140 nuclei.

  14. RADIATION STABILITY OF NAFION MEMBRANES USED FOR ISOTOPE SEPARATION BY PROTON EXCHANGE MEMBRANE ELECTROLYSIS

    SciTech Connect

    Fox, E

    2009-05-15

    Proton Exchange Membrane Electrolyzers have potential interest for use for hydrogen isotope separation from water. In order for PEME to be fully utilized, more information is needed on the stability of Nafion when exposed to radiation. This work examines Nafion 117 under varying exposure conditions, including dose rate, total dosage and atmospheric condition. Analytical tools, such as FT-IR, ion exchange capacity, DMA and TIC-TOC were used to characterize the exposed membranes. Analysis of the water from saturated membranes can provide important data on the stability of the membranes during radiation exposure. It was found that the dose rate of exposure plays an important role in membrane degradation. Potential mechanisms for membrane degradation include peroxide formation by free radicals.

  15. Carbon isotope separation and molecular formation in laser-induced plasmas by laser ablation molecular isotopic spectrometry.

    PubMed

    Dong, Meirong; Mao, Xianglei; Gonzalez, Jhanis J; Lu, Jidong; Russo, Richard E

    2013-03-05

    Laser ablation molecular isotopic spectrometry (LAMIS) recently was reported for rapid isotopic analysis by measuring molecular emission from laser-induced plasmas at atmospheric pressure. This research utilized the LAMIS approach to study C2 molecular formation from laser ablation of carbon isotopic samples in a neon gas environment at 0.1 MPa. The isotopic shift for the Swan system of the C2 Δν = 1 band was chosen for carbon isotope analysis. Temporal and spatial resolved measurements of (12)C2, (12)C(13)C, and (13)C2 show that C2 forms from recombination reactions in the plasma. A theoretical simulation was used to determine the temperature from the molecular bands and to extract the isotopic ratio of (12)C/(13)C derived from (12)C2, (12)C(13)C, and (13)C2. Our data show that the ratio of (12)C/(13)C varies with time after the laser pulse and with distance above the sample. (12)C/(13)C deviates from the nominal ratio (2:1) at early times and closest to the sample surface. These measurements provide understanding of the chemical processes in the laser plasma and analytical improvement using LAMIS.

  16. Isotopic separation of snowmelt runoff during an artificial rain-on-snow event

    NASA Astrophysics Data System (ADS)

    Juras, Roman; Pavlasek, Jirka; Šanda, Martin; Jankovec, Jakub; Linda, Miloslav

    2013-04-01

    Rain-on-snow events are common phenomenon in the climate conditions of central Europe, mainly during the spring snowmelt period. These events can cause serious floods in areas with seasonal snow. The snowpack hit by rain is able to store a fraction of rain water, but runoff caused by additional snowmelt also increases. Assessment of the rainwater ratio contributing to the outflow from the snowpack is therefore critical for discharge modelling. A rainfall simulator and water enriched by deuterium were used for the study of rainwater behaviour during an artificial rain-on-snow event. An area of 1 m2 of the snow sample, which was 1.2 m deep, consisting of ripped coarse-grained snow, was sprayed during the experiment with deuterium enriched water. The outflow from the snowpack was measured and samples of outflow water were collected. The isotopic content of deuterium was further analyzed from these samples by means of laser spectroscopy for the purpose of hydrograph separation. The concentration of deuterium in snow before and after the experiment was also investigated. The deuterium enriched water above the natural concentration of deuterium in snowpack was detected in the outflow in 7th minute from start of spraying, but the significant increase of deuterium concentration in outflow was observed in 19th minute. The isotopic hydrograph separation estimated, that deuterium enriched rainwater became the major part (> 50% volumetric) of the outflow in 28th minute. The culmination of the outflow (1.23 l min-1) as well as deuterium enriched rainwater fraction (63.5%) in it occurred in 63th minute, i.e. right after the end of spraying. In total, 72.7 l of deuterium enriched water was sprayed on the snowpack in 62 minutes. Total volume of outflow (after 12.3 hours) water was 97.4 l, which contained 48.3 l of deuterium enriched water (i.e. 49.6 %) and 49.1 l (50.4 %) of the melted snowpack. The volume of 24.4 l of deuterium enriched spray-water was stored in the snowpack. The

  17. Spatial variability in the isotopic composition of rainfall in a small headwater catchment and its effect on hydrograph separation

    NASA Astrophysics Data System (ADS)

    Fischer, Benjamin M. C.; van Meerveld, H. J. (Ilja); Seibert, Jan

    2017-04-01

    Isotope hydrograph separation (IHS) is a valuable tool to study runoff generation processes. To perform an IHS, samples of baseflow (pre-event water) and streamflow are taken at the catchment outlet. For rainfall (event water) either a bulk sample is collected or it is sampled sequentially during the event. For small headwater catchment studies, event water samples are usually taken at only one sampling location in or near the catchment because the spatial variability in the isotopic composition of rainfall is assumed to be small. However, few studies have tested this assumption. In this study, we investigated the spatiotemporal variability in the isotopic composition of rainfall and its effects on IHS results using detailed measurements from a small pre-alpine headwater catchment in Switzerland. Rainfall was sampled sequentially at eight locations across the 4.3 km2 Zwäckentobel catchment and stream water was collected in three subcatchments (0.15, 0.23, and 0.70 km2) during ten events. The spatial variability in rainfall amount, average and maximum rainfall intensity and the isotopic composition of rainfall was different for each event. There was no significant relation between the isotopic composition of rainfall and total rainfall amount, rainfall intensity or elevation. For eight of the ten studied events the temporal variability in the isotopic composition of rainfall was larger than the spatial variability in the rainfall isotopic composition. The isotope hydrograph separation results, using only one rain sampler, varied considerably depending on which rain sampler was used to represent the isotopic composition of event water. The calculated minimum pre-event water contributions differed up to 60%. The differences were particularly large for events with a large spatial variability in the isotopic composition of rainfall and a small difference between the event and pre-event water isotopic composition. Our results demonstrate that even in small catchments

  18. A modified lead-matrix separation procedure shown for lead isotope analysis in Trojan silver artefacts as an example.

    PubMed

    Vogl, Jochen; Paz, Boaz; Koenig, Maren; Pritzkow, Wolfgang

    2013-03-01

    A modified Pb-matrix separation procedure using NH4HCO3 solution as eluent has been developed and validated for determination of Pb isotope amount ratios by thermal ionization mass spectrometry. The procedure is based on chromatographic separation using the Pb·Spec resin and an in-house-prepared NH4HCO3 solution serving as eluent. The advantages of this eluent are low Pb blanks (<40 pg mL(-1)) and the property that NH4HCO3 can be easily removed by use of a heating step (>60 °C). Pb recovery is >95 % for water samples. For archaeological silver samples, however, the Pb recovery is reduced to approximately 50 %, but causes no bias in the determination of Pb isotope amount ratios. The validated procedure was used to determine lead isotope amount ratios in Trojan silver artefacts with expanded uncertainties (k = 2) <0.09 %.

  19. The importance of snowmelt spatiotemporal variability for isotope-based hydrograph separation in a high-elevation catchment

    NASA Astrophysics Data System (ADS)

    Schmieder, Jan; Hanzer, Florian; Marke, Thomas; Garvelmann, Jakob; Warscher, Michael; Kunstmann, Harald; Strasser, Ulrich

    2016-12-01

    Seasonal snow cover is an important temporary water storage in high-elevation regions. Especially in remote areas, the available data are often insufficient to accurately quantify snowmelt contributions to streamflow. The limited knowledge about the spatiotemporal variability of the snowmelt isotopic composition, as well as pronounced spatial variation in snowmelt rates, leads to high uncertainties in applying the isotope-based hydrograph separation method. The stable isotopic signatures of snowmelt water samples collected during two spring 2014 snowmelt events at a north- and a south-facing slope were volume weighted with snowmelt rates derived from a distributed physics-based snow model in order to transfer the measured plot-scale isotopic composition of snowmelt to the catchment scale. The observed δ18O values and modeled snowmelt rates showed distinct inter- and intra-event variations, as well as marked differences between north- and south-facing slopes. Accounting for these differences, two-component isotopic hydrograph separation revealed snowmelt contributions to streamflow of 35 ± 3 and 75 ± 14 % for the early and peak melt season, respectively. These values differed from those determined by formerly used weighting methods (e.g., using observed plot-scale melt rates) or considering either the north- or south-facing slope by up to 5 and 15 %, respectively.

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

    SciTech Connect

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

    2010-08-11

    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.

  1. COSY Simulations to Guide Commissioning of the St. George Recoil Mass Separator

    NASA Astrophysics Data System (ADS)

    Schmitt, Jaclyn; Moran, Michael; Seymour, Christopher; Gilardy, Gwenaelle; Meisel, Zach; Couder, Manoel

    2015-10-01

    The goal of St. George (STrong Gradient Electromagnetic Online Recoil separator for capture Gamma ray Experiments) is to measure (α, γ) cross sections relevant to stellar helium burning. Recoil separators such as St. George are able to more closely approach the low astrophysical energies of interest because they collect reaction recoils rather than γ-rays, and thus are not limited by room background. In order to obtain an accurate cross section measurement, a recoil separator must be able to collect all recoils over their full range of expected energy and angular spread. The energy acceptance of St. George is currently being measured, and the angular acceptance will be measured soon. Here we present the results of COSY ion optics simulations and magnetic field analyses which were performed to help guide the commissioning measurements and diagnostic upgrades required to complete those measurements. National Science Foundation Research Experiences for Undergraduates program.

  2. Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Ghaly, Michael; Links, Jonathan M.; Frey, Eric C.

    2015-07-01

    Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6-5 and acquisition energy window widths of 16-22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16-22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

  3. Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT

    PubMed Central

    Ghaly, Michael; Links, Jonathan M; Frey, Eric C

    2015-01-01

    Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6–5 and acquisition energy window widths of 16–22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16–22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

  4. Modified ion exchange separation for tungsten isotopic measurements from kimberlite samples using multi-collector inductively coupled plasma mass spectrometry.

    PubMed

    Sahoo, Yu Vin; Nakai, Shun'ichi; Ali, Arshad

    2006-03-01

    Tungsten isotope composition of a sample of deep-seated rock can record the influence of core-mantle interaction of the parent magma. Samples of kimberlite, which is known as a carrier of diamond, from the deep mantle might exhibit effects of core-mantle interaction. Although tungsten isotope anomaly was reported for kimberlites from South Africa, a subsequent investigation did not verify the anomaly. The magnesium-rich and calcium-rich chemical composition of kimberlite might engender difficulty during chemical separation of tungsten for isotope analyses. This paper presents a simple, one-step anion exchange technique for precise and accurate determination of tungsten isotopes in kimberlites using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Large quantities of Ca and Mg in kimberlite samples were precipitated and removed with aqueous H(2)SO(4). Highly pure fractions of tungsten for isotopic measurements were obtained following an anion exchange chromatographic procedure involving mixed acids. That procedure enabled efficient removal of high field strength elements (HFSE), such as Hf, Zr and Ti, which are small ions that carry strong charges and develop intense electrostatic fields. The tungsten yields were 85%-95%. Advantages of this system include less time and less use of reagents. Precise and accurate isotopic measurements are possible using fractions of tungsten that are obtained using this method. The accuracy and precision of these measurements were confirmed using various silicate standard rock samples, JB-2, JB-3 and AGV-1.

  5. Isotope Separation and Advanced Manufacturing Technology. ISAM semiannual report, Volume 3, Number 1, October 1993--March 1994

    SciTech Connect

    Carpenter, J.; Kan, T.

    1994-10-01

    This is the fourth issue of a semiannual report for the Isotope Separation and Advanced Materials Manufacturing (ISAM) Technology Program at Lawrence Livermore National Laboratory. Primary objectives include: (I) the Uranium Atomic Vapor Laser Isotope Separation (UAVLIS) process, which is being developed and prepared for deployment as an advanced uranium enrichment capability; (II) Advanced manufacturing technologies, which include industrial laser and E-beam material processing and new manufacturing technologies for uranium, plutonium, and other strategically important materials in support of DOE and other national applications. This report features progress in the ISAM Program from October 1993 through March 1994. Selected papers were indexed separately for inclusion in the Energy Science and Technology Database.

  6. Hydrograph separation using stable isotopes, silica and electrical conductivity: an alpine example

    NASA Astrophysics Data System (ADS)

    Laudon, Hjalmar; Slaymaker, Olav

    1997-12-01

    Hydrograph separation of runoff events in two nested alpine/subalpine basins in the Coast Mountains of British Columbia was carried out using electrical conductivity, specific concentration of silica and the stable isotopes oxygen-18 and deuterium as hydrological tracers. The methods predicted consistent high pre-storm water contribution for the subalpine site (60-90%) but more variable contribution at the alpine basin outlet (25-90%). The pre-storm water contribution is much larger than had previously been expected. Precipitation is believed to run off as overland flow due to the steep slopes in combination with the hydrophobic soils until it can enter the subsurface environment. The rapid influx of stored water is possibly caused by pressure propagation in the macropore system which could be enhanced by the heavily fractured bedrock and permeable landslide debris acting as efficient hydrological conduits. The study suggests that alternative hydrological tracers such as electrical conductivity and silica concentration can be used under certain hydrological and lithological conditions. These alternative tracers should, however, be verified against more conventional tracers before use, as the behaviour depends on specific characteristics of each basin. At the upper basin outlet, both electrical conductivity (EC) and silica underestimated the pre-storm contribution. At the lower station, silica and EC showed a similar pattern to deuterium and oxygen-18 tracers. The calculated pre-storm component using EC was, however, 10-20% lower than the calculated values from the other three tracers. The advantage of using these alternative tracers is that hydrograph separation results can, a priori, be anticipated.

  7. Preparative separation of arsenate from phosphate by IRA-400 (OH) for oxygen isotopic work.

    PubMed

    Tang, Xiaohui; Berner, Zsolt; Khelashvilli, Pirimze; Norra, Stefan

    2013-02-15

    The paper reports about a series of tests carried out to find out the optimal conditions for the preparative separation of arsenate and phosphate from natural waters, using the anion exchange resin Amberlite IRA-400 (OH). Freundlich isotherms have been constructed on basis of data obtained by stirring different amounts of resin (0.05-1.00 g) with solutions containing 1mg/L As and 10mg/L P in form of arsenate and phosphate and the effect of pH and P/As ratio on adsorption was investigated. It was found that at these concentrations 0.5 g of IRA-400 (OH) can adsorb quantitatively arsenate and phosphate within 1h. In a range of 3.6-11.1, pH seems to have no influence on the adsorption behavior of the resin, but at pH 1.5 the adsorption of both arsenate and phosphate drops to values close to zero. Experiments with solutions with P/As ratios in a range between 1 and 30 have shown that the concentration ratios have also little effect on adsorption. An efficient selective desorption of the anions could be achieved with 2 mol/L HNO3 or HCl, but the use of HCl is impracticable if the separation aims at precipitating arsenate for oxygen isotopic work. The reported adsorption/ desorption properties of the resin are supported also by data obtained by investigating the resin particles with a scanning electron microscope equipped with a fluorescence detection device.

  8. Calculations on Isotope Separation by Laser Induced Photodissociation of Polyatomic Molecules. Final Report

    DOE R&D Accomplishments Database

    Lamb, W. E. Jr.

    1978-11-01

    This report describes research on the theory of isotope separation produced by the illumination of polyatomic molecules by intense infrared laser radiation. Newton`s equations of motion were integrated for the atoms of the SF{sub 6} molecule including the laser field interaction. The first year`s work has been largely dedicated to obtaining a suitable interatomic potential valid for arbitrary configurations of the seven particles. This potential gives the correct symmetry of the molecule, the equilibrium configuration, the frequencies of the six distinct normal modes of oscillation and the correct (or assumed) value of the total potential energy of the molecule. Other conditions can easily be imposed in order to obtain a more refined potential energy function, for example, by making allowance for anharmonicity data. A suitable expression was also obtained for the interaction energy between a laser field and the polyatomic molecule. The electromagnetic field is treated classically, and it would be easily possible to treat the cases of time dependent pulses, frequency modulation and noise.

  9. The direct determination of the masses of unstable atoms with the chalk river on-line isotope separator

    NASA Astrophysics Data System (ADS)

    Sharma, K. S.; Schmeing, H.; Evans, H. C.; Hagberg, E.; Hardy, J. C.; Koslowsky, V. T.

    1989-02-01

    A new technique has been developed to measure the spacing of atomic mass doublets of radioactive isotopes directly with an on-line isotope separator. It relies not on ion detection but on observation of the specific radioactive signature of the isotopes under study. Consequently, line shapes and centroids can be determined, free of interference and with great accuracy, even if the corresponding beams strongly overlap or if they are contaminated by unwanted isobars or isomers. In particular, it is of no consequence if one or both members of the doublet are masked by stable background peaks. Doublets are peak matched as in a conventional mass spectrometer. The technique has been evaluated with beams of radioactive nuclides whose masses are known independently. Based on careful calibrations, two new mass values have been obtained: 72Br, 71 936 340 ± 430 μu and 63Ga, 62 939 570 ± 150 μu.

  10. Therapeutic Antibody Engineering To Improve Viscosity and Phase Separation Guided by Crystal Structure.

    PubMed

    Chow, Chi-Kin; Allan, Barrett W; Chai, Qing; Atwell, Shane; Lu, Jirong

    2016-03-07

    Antibodies at high concentrations often reveal unanticipated biophysical properties suboptimal for therapeutic development. The purpose of this work was to explore the use of point mutations based on crystal structure information to improve antibody physical properties such as viscosity and phase separation (LLPS) at high concentrations. An IgG4 monoclonal antibody (Mab4) that exhibited high viscosity and phase separation at high concentration was used as a model system. Guided by the crystal structure, four CDR point mutants were made to evaluate the role of hydrophobic and charge interactions on solution behavior. Surprisingly and unpredictably, two of the charge mutants, R33G and N35E, showed a reduction in viscosity and a lower propensity to form LLPS at high concentration compared to the wild-type (WT), while a third charge mutant S28K showed an increased propensity to form LLPS compared to the WT. A fourth mutant, F102H, had reduced hydrophobicity, but unchanged viscosity and phase separation behavior. We further evaluated the correlation of various biophysical measurements including second virial coefficient (A2), interaction parameter (kD), weight-average molecular weight (WAMW), and hydrodynamic diameters (DH), at relatively low protein concentration (4 to 15 mg/mL) to physical properties, such as viscosity and liquid-liquid phase separation (LLPS), at high concentration. Surprisingly, kD measured using dynamic light scattering (DLS) at low antibody concentration correlated better with viscosity and phase separation than did A2 for Mab4. Our results suggest that the high viscosity and phase separation observed at high concentration for Mab4 are mainly driven by charge and not hydrophobicity.

  11. On-line experimental results of an argon gas cell-based laser ion source (KEK Isotope Separation System)

    NASA Astrophysics Data System (ADS)

    Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Kimura, S.; Mukai, M.; Kim, Y. H.; Sonoda, T.; Wada, M.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

    2016-06-01

    KEK Isotope Separation System (KISS) has been developed at RIKEN to produce neutron rich isotopes with N = 126 to study the β -decay properties for application to astrophysics. The KISS is an element-selective mass-separation system which consists of an argon gas cell-based on laser ion source for atomic number selection and an ISOL mass-separation system. The argon gas cell of KISS is a key component to stop and collect the unstable nuclei produced in a multi-nucleon transfer reaction, where the isotopes of interest will be selectively ionized using laser resonance ionization. We have performed off- and on-line experiments to study the basic properties of the gas cell as well as of the KISS. We successfully extracted the laser-ionized stable 56Fe (direct implantation of a 56Fe beam into the gas cell) atoms and 198Pt (emitted from the 198Pt target by elastic scattering with a 136Xe beam) atoms from the KISS during the commissioning on-line experiments. We furthermore extracted laser-ionized unstable 199Pt atoms and confirmed that the measured half-life was in good agreement with the reported value.

  12. Practical-scale tests of cryogenic molecular sieve for separating low-concentration hydrogen isotopes from helium

    NASA Astrophysics Data System (ADS)

    Willms, R. S.; Taylor, D. J.; Enoeda, Mikio; Okuno, Kenji

    1994-04-01

    Earlier bench-scale work at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory examined a number of adsorbents for their suitability for separating low-concentration hydrogen (no tritium) from helium. One of the effective adsorbents was Linde 5A molecular sieve. Recently, experiments including tritium were conducted using practical-scale adsorbers. These tests used existing cryogenic molecular sieve beds (CMSB's) which each contain about 1.6 kg of Linde 5A molecular sieve. They are part of the TSTA integrated tritium processing system. Gas was fed to each CMSB at about 13 SLPM with a nominal composition of 99% He, 0.98% H2, and 0.02% HT. In all cases, for an extended period of time, the beds allowed no detectable (via Raman spectroscopy) hydrogen isotopes to escape in the bed effluent. Thereafter, the hydrogen isotopes appeared in the bed exit with a relatively sharp breakthrough curve. This work concludes that cryogenic molecular sieve adsorption is a practical and effective means of separating low-concentration hydrogen isotopes from a helium carrier.

  13. Separating the contributions of vegetation and soil to evapotranspiration using stable isotopes

    NASA Astrophysics Data System (ADS)

    Cuntz, Matthias; Dubbert, Maren; Piayda, Arndt; Correia, Alexandra; Silva, Filipe Costa e.; Kolle, Olaf; Maguás, Cristina; Mosena, Alexander; Pereira, João S.; Rebmann, Corinna; Werner, Christiane

    2015-04-01

    Semi-arid ecosystems contribute about 40% to global net primary productivity, although water-availability limits carbon uptake. Precipitation shows periodical summer droughts and evapotranspiration accounts for up to 95% of water loss of the ecosystem. Thus functional understanding of evapotranspiration and the contributions of evaporation and transpiration from over- and understorey vegetation to water cycling in semi-arid regions is key knowledge in forest management under future climate change. Water isotopes trace water through the compartments of an ecosystem from soil and the vegetation to the atmosphere. They are used to partition evapotranspiration ET into its components evaporation E and transpiration T . The method is, however, sensitive to the knowledge of the isotopic composition of water at the evaporating sites. This led to a discussion recently about the dominance of transpiration in water loss from the terrestrial biosphere, and also how methodological problems could bias these results. Here we present observations from a Portuguese cork-oak woodland. It is a bi-layered system of widely spaced cork-oak trees and a herbaceous layer dominated by native annual forbs and grasses. Water fluxes and their isotopic compositions were measured on bare soil and vegetated plots with a transparent through-flow chamber and a water isotope laser. Soil moisture and temperature were measured in several depths and soil samples were taken for soil water isotope analysis. Based on these observations, we review current strategies of ET partitioning. We highlight pitfalls in the presented strategies and show uncertainty analyses for the different approaches. We show that the isotopic composition of evaporation is very sensitive to the sampling strategy but is described well by a steady-state formulation (Dubbert et al., J Hydrolo 2013). The isotopic composition of transpiration, on the other hand, is not in steady state, most of the time (Dubbert et al., New Phytolo 2014

  14. Gas chromatographic separation of hydrogen isotopes on columns packed with alumina, modified alumina and sol-gel alumina.

    PubMed

    Naik, Y P; Gupta, N K; Pillai, K T; Rao, G A Rama; Venugopal, V

    2012-01-06

    The stationary phase of alumina adsorbents, prepared by different chemical processes, was used to study the separation behaviour of hydrogen isotopes. Three types of alumina, obtained by conventional hydroxide route alumina coated with silicon oxide and alumina prepared by internal gelation process (IGP), were used as packing material to study the separation of HT and T(2) in a mixture at various temperatures. The conventional alumina and silicon oxide coated alumina resolved HT and T(2) at 77K temperature with different retention times. The retention times on SiO(2) coated columns were found to be higher than those of other adsorbents. However, the column filled with IGP alumina was found to be ideal for the separation of HT and T(2) at 240 K. The peaks were well resolved in less than 5 min on this column.

  15. Isotopic anomalies of Ne, Xe, and C in meteorites. I - Separation of carriers by density and chemical resistance

    NASA Technical Reports Server (NTRS)

    Ming, Tang; Lewis, Roy S.; Anders, Edward; Grady, M. M.; Wright, I. P.

    1988-01-01

    The carriers of presolar noble gases were studied by isotopically analyzing 19 separates from the Murray and Murchison C2 chondrites for Ne, Xe, C, and N. It is found that the carriers of Ne-E(H) and Xe-S are resistant to HCl, HF, boiling HClO4, and CrO3-H2SO4, and thus must be either diamond or some resistant carbide or oxide. The carrier of Ne-E(L) may be some form of amorphous carbon with delta C13 of about +340 percent. A new carbon component, C theta, found as 0.2-2-micron inclusions in Murchison spinel, is amorphous and contains little or no noble gas. A new heavy nitrogen component is found which has an abundance of about 1 ppm in the bulk meteorite, combusts at 450-500 C, and may be associated wtih isotopically normal carbon or with C-alpha.

  16. Determination of Plutonium Isotope Ratios at Very Low Levels by ICP-MS using On-Line Electrochemically Modulated Separations

    SciTech Connect

    Liezers, Martin; Lehn, Scott A; Olsen, Khris B; Farmer, Orville T; Duckworth, Douglas C

    2009-10-01

    Electrochemically modulated separations (EMS) are shown to be a rapid and selective means of extracting and concentrating Pu from complex solutions prior to isotopic analysis by inductively coupled plasma mass spectrometry (ICP-MS). This separation is performed in a flow injection mode, on-line with the ICP-MS. A three-electrode, flow-by electrochemical cell is used to accumulate Pu at an anodized glassy carbon electrode by redox conversion of Pu(III) to Pu (IV&VI). The entire process takes place in 2% v/v (0.46M) HNO3. No redox chemicals or acid concentration changes are required. Plutonium accumulation and release is redox dependent and controlled by the applied cell potential. Thus large transient volumetric concentration enhancements can be achieved. Based on more negative U(IV) potentials relative to Pu(IV), separation of Pu from uranium is efficient, thereby eliminating uranium hydride interferences. EMS-ICP-MS isotope ratio measurement performance will be presented for femtogram to attogram level plutonium concentrations.

  17. Plasma centrifuge with vacuum arc discharge applied to the separation of stable isotopes

    NASA Astrophysics Data System (ADS)

    Delbosco, Edson

    1989-09-01

    The results of a vacuum-arc plasma centrifuge experiment are described. A plasma centrifuge is an apparatus where a plasma column is produced due to the interaction of an electric current with an externally applied magnetic field, vector J x vector B. Among the applications of a rotating plasma, this work deals particularly with its utilization in an isotope enrichment device. The main characteristics of the plasma produced in this experiment are presented, with special attention to the plasma column rotation and the isotope enrichment. The analysis of the results is performed using a fluid model for a completely ionized rigid body rotating plasma column in steady state equilibrium. The main results are: (1) rotation frequency of the plasma column in the range 2 x (exp 4) to 3 x 10 (exp 5) rad/s; (2) enrichment of 10 to 30 pct for the magnesium isotopes, and 290 to 490 pct for the carbon-13 isotope; (3) rigid body rotation of the plasma column only for radii smaller than the characteristic radius of the plasma column, r(sub e); (4) linear dependence of the rotation frequency upon the magnetic field strength only for r is less than r(sub e); (5) existence of an optimum value of the magnetic field for maximum enrichment; and (6) dependence of the rotation frequency upon the inverse of the atomic mass.

  18. Golan Heights Groundwater Systems: Separation By REE+Y And Stable Isotopes

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Geyer, S.; Knoeller, K.; Roediger, T.; Weise, S.; Dulski, P.; Moeller, P.; Guttman, J.

    2008-12-01

    In a semi-arid to arid country like Israel, all freshwater resources are under (over-) utilization. Particularly, the Golan Heights rank as one of the most important extraction areas of groundwater of good quality and quantity. Additionally the mountain range feed to a high degree the most important freshwater reservoir of Israel, the Sea of Galilee. Hence, knowing the sources and characters of the Golan Heights groundwater systems is an instantaneous demand regarding sustainable management and protection. Within the "German-Israeli-Jordanian-Palestinian Joint Research Program for the Sustainable Utilisation of Aquifer Systems", hundreds of water samples were taken from all over the Jordan-Dead Sea rift-system to understand groundwater flow-systems and salinisation. For that purpose, each sample was analysed for major and minor ions, rare earth elements including yttrium (REY) and stable isotopes of water (d18O, d2H). The REY distribution in groundwater is established during infiltration by the first water-rock interaction and consequently reflects the leachable components of sediments and rocks of the recharge area. In well- developed flow-systems, REY are adsorbed onto pore surfaces are in equilibrium with the percolating groundwater, even if the lithology changes (e.g. inter-aquifer flow). Thus, groundwater sampled from wells and springs still show the REY distribution pattern established in the recharge area. Since high temperatures do not occur in Golan Heights, d2H and d18O are less controlled by water-rock interaction than by climatic and geomorphological factors at the time of replenishment. Applying the REY signature as a grouping criterion of groundwaters, d18O vs. d2H plots yield a new dimension in interpreting isotope data. The combined use of hydrochemical and isotopic methods enabled us to contain the areas of replenishment and the flow-paths of all investigated groundwater in the Golan Heights. Despite location, salinity or temperature of spring or

  19. Stable isotope analysis of diet confirms niche separation of two sympatric species of Namib Desert lizard.

    PubMed

    Murray, Ian W; Lease, Hilary M; Hetem, Robyn S; Mitchell, Duncan; Fuller, Andrea; Woodborne, Stephan

    2016-01-01

    We used stable isotopes of carbon and nitrogen to study the trophic niche of two species of insectivorous lizards, the Husab sand lizard Pedioplanis husabensis and Bradfield's Namib day gecko living sympatrically in the Namib Desert. We measured the δ(13) C and δ(15) N ratios in lizard blood tissues with different turnover times (whole blood, red blood cells and plasma) to investigate lizard diet in different seasons. We also measured the δ(13) C and δ(15) N ratios in available arthropod prey and plant tissues on the site, to identify the avenues of nutrient movement between lizards and their prey. Through the use of stable isotope mixing models, we found that the two lizard species relied on a largely non-overlapping but seasonally variable array of arthropods: P. husabensis primarily fed on termites, beetles and wasps, while R. bradfieldi fed mainly on ants, wasps and hemipterans. Nutrients originating from C3 plants were proportionally higher for R. bradfieldi than for P. husabensis during autumn and late autumn/early winter, although not summer. Contrary to the few available data estimating the trophic transfer of nutrients in ectotherms in mixed C3 and C4 /crassulacean acid metabolism (CAM) plant landscapes, we found that our lizard species primarily acquired nutrients that originated from C4 /CAM plants. This work adds an important dimension to the general lack of studies using stable isotope analyses to estimate lizard niche partitioning and resource use.

  20. Lead isotope systematics of some Apollo 17 soils and some separated components from 76501

    NASA Technical Reports Server (NTRS)

    Church, S. E.; Tilton, G. R.

    1974-01-01

    Isotopic lead data from bulk samples of Apollo 17 soils were analyzed, and they define a chord in a concordia diagram, showing the presence of a component or components containing excess radiogenic lead with Pb-207/Pb-206 equal to about 1.32. The chord is distinctly different from the cataclysm chord, for which Pb-207/Pb-206 is approximately 1.45. Nitric acid analysis of plagioclase indicates lead ages of around 4.35 AE, in agreement with previous findings. Agglutinates from soil 76501,34 show loss of approximately 15% of lead.

  1. Isotopic and Elemental Composition of Roasted Coffee as a Guide to Authenticity and Origin.

    PubMed

    Carter, James F; Yates, Hans S A; Tinggi, Ujang

    2015-06-24

    This study presents the stable isotopic and elemental compositions of single-origin, roasted coffees available to retail consumers. The δ(13)C, δ(15)N, and δ(18)O compositions were in agreement with those previously reported for green coffee beans. The δ(15)N composition was seen to be related to organic cultivation, reflected in both δ(2)H and δ(18)O compositions. The δ(13)C composition of extracted caffeine differed little from that of the bulk coffee. Stepwise discriminant analysis with jackknife tests, using isotopic and elemental data, provided up to 77% correct classification of regions of production. Samples from Africa and India were readily classified. The wide range in both isotopic and elemental compositions of samples from other regions, specifically Central/South America, resulted in poor discrimination between or within these regions. Simpler X-Y and geo-spatial plots of the isotopic data provided effective visual means to distinguish between coffees from different regions.

  2. Continuous production of tritium in an isotope-production reactor with a separate circulation system

    DOEpatents

    Cawley, W.E.; Omberg, R.P.

    1982-08-19

    A method is described for producing tritium in a fast breeder reactor cooled with liquid metal. Lithium is allowed to flow through the reactor in separate loops in order to facilitate the production and removal of tritium.

  3. Hydrogen isotope separation in carbon nanotubes: calculation of coupled rotational and translational States at high densities.

    PubMed

    Garberoglio, Giovanni; Johnson, J Karl

    2010-03-23

    The effect of the quantized rotational degrees of freedom of hydrogen on the adsorption and sieving properties in carbon nanotubes is studied using computer simulations. We have developed a highly efficient multiple timestep algorithm for hybrid Monte Carlo sampling of quantized rotor configurations and extended the grand canonical Boltzmann bias method to rigid linear molecules. These new computational tools allow us to calculate accurately the quantum sieving selectivities for cases of extreme two-dimensional confinement as a function of pressure. The para-T2/para-H2 selectivity at 20 K is analyzed as a function of the tube diameter and the density of adsorbed hydrogen. Extraordinarily high selectivities, up to 2.6 x 10(8), are observed in the narrowest nanotube. The quantized nature of the rotational degrees of freedom is found to dramatically affect adsorption and selectivity for hydrogen isotopes adsorbed in very narrow nanotubes. The T2/H2 zero-pressure selectivity increases from 2.4 x 10(4) to 1.7 x 10(8) in the (3,6) nanotube at 20 K when quantum rotations are accounted for. The isotopic selectivity is found to increase with pressure, tending to a constant value at saturation. A simplified mean-field model is used to discuss the origin of this behavior.

  4. Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples

    NASA Astrophysics Data System (ADS)

    Miyazaki, Takashi; Vaglarov, Bogdan Stefanov; Takei, Masakazu; Suzuki, Masahiro; Suzuki, Hiroaki; Ohsawa, Kouzou; Chang, Qing; Takahashi, Toshiro; Hirahara, Yuka; Hanyu, Takeshi; Kimura, Jun-Ichi; Tatsumi, Yoshiyuki

    A fully automated open-column resin-bed chemical-separation system, named COLUMNSPIDER, has been developed. The system consists of a programmable micropipetting robot that dispenses chemical reagents and sample solutions into an open-column resin bed for elemental separation. After the initial set up of resin columns, chemical reagents, and beakers for the separated chemical components, all separation procedures are automated. As many as ten samples can be eluted in parallel in a single automated run. Many separation procedures, such as radiogenic isotope ratio analyses for Sr and Nd, involve the use of multiple column separations with different resin columns, chemical reagents, and beakers of various volumes. COLUMNSPIDER completes these separations using multiple runs. Programmable functions, including the positioning of the micropipetter, reagent volume, and elution time, enable flexible operation. Optimized movements for solution take-up and high-efficiency column flushing allow the system to perform as precisely as when carried out manually by a skilled operator. Procedural blanks, examined for COLUMNSPIDER separations of Sr, Nd, and Pb, are low and negligible. The measured Sr, Nd, and Pb isotope ratios for JB-2 and Nd isotope ratios for JB-3 and BCR-2 rock standards all fall within the ranges reported previously in high-accuracy analyses. COLUMNSPIDER is a versatile tool for the efficient elemental separation of igneous rock samples, a process that is both labor intensive and time consuming.

  5. Recent developments of the ion sources at Tri University Meson Factory/Isotope Separator and ACcelerator Facility.

    PubMed

    Bricault, P G; Ames, F; Dombsky, M; Labrecque, F; Lassen, J; Mjos, A; Minor, G; Tigelhoefer, A

    2012-02-01

    This paper describes the recent progresses concerning the on-line ion source at the Tri University Meson Factory/Isotope Separator and ACcelerator (TRIUMF/ISAC) Radioactive Ion-Beam Facility; description of the new design of the surface-ion-source for improved stability of the beam intensity, description of the transport path to the east target station at ISAC, description of the new brazing techniques that solved recurrent problems with water leaks on the target/ion source assembly in the vacuum system, finally, recent developments concerning the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source are reported. In particular, a study on the effect of the plasma chamber volume on the ionization efficiency was completed.

  6. Boundary-value problem for a counterrotating electrical discharge in an axial magnetic field. [plasma centrifuge for isotope separation

    NASA Technical Reports Server (NTRS)

    Hong, S. H.; Wilhelm, H. E.

    1978-01-01

    An electrical discharge between two ring electrodes embedded in the mantle of a cylindrical chamber is considered, in which the plasma in the anode and cathode regions rotates in opposite directions under the influence of an external axial magnetic field. The associated boundary-value problem for the coupled partial differential equations describing the azimuthal velocity and radial current-density fields is solved in closed form. The velocity, current density, induced magnetic induction, and electric fields are presented for typical Hartmann numbers, magnetic Reynolds numbers, and geometry parameters. The discharge is shown to produce anodic and cathodic plasma sections rotating at speeds of the order 1,000,000 cm/sec for conventional magnetic field intensities. Possible application of the magnetoactive discharge as a plasma centrifuge for isotope separation is discussed.

  7. Baseflow separation in a premontane transitional rainforest using stable isotope techniques

    NASA Astrophysics Data System (ADS)

    Miller, G. R.; DuMont, A.; Roark, E.; Cahill, A. T.; Brumbelow, J. K.

    2013-12-01

    Hydrologic, geologic, and biologic processes are critical to understanding the ecosystem in the tropical premontane transitional forests of Costa Rica. Precipitation is significantly lower during the dry season, and incoming rainfall can be completely intercepted and re-evaporated by the canopy during light events. These canopy processes can affect the rates of runoff and infiltration by changing the quantity and timing of rainfall reaching the ground surface. However, the resulting partitioning of stream water sources between event-water and baseflow from groundwater is not well quantified due to limited accessibility and complex subsurface conditions. This study focuses on research conducted at the Texas A&M Soltis Center for Education and Research, near San Ramón, Costa Rica. We have monitored a 2.2 ha watershed there, measuring precipitation and transpiration rates for over two years, and groundwater levels and stream flow rates for nearly one year. Precipitation rates for the watershed averaged 4.4 m/yr since 2010. Stream flow (runoff, spring flow, and baseflow) averaged 0.09 m^3/sec during the 2012-2013 wet seasons. At 1.2 mm/day, transpiration was a relatively minor component of the water budget. Over a 40-day span during summer 2013, we collected a combination of daily and rain-event based samples from locations throughout the watershed. Sources included: the main stream and two small tributaries, groundwater from piezometers, pore water from suction lysimeters, throughfall and stemflow from under canopy collection systems, and xylem water from 8 tree species across the watershed. We then measured stable isotope fractions (δ18O and δD) in the water using a Picarro L2120i CRDS. Isotope ratios for all surface water averaged -5.50‰ for δ18O and -28.00‰ for δD, while that measured under baseflow conditions were -5.45‰ for δ18O and -29.18‰ for δD. These results indicate that baseflow is the dominate source of stream water even in the wet season

  8. Separating Continental Mineral Dust from Cosmic Dust using Platinum Group Element Concentrations and Osmium Isotopes in Ancient Polar Ice

    NASA Astrophysics Data System (ADS)

    Seo, J. H.; Jackson, B.; Osterberg, E. C.; Sharma, M.

    2015-12-01

    The platinum group element (PGEs: Pt, Pd, Rh, Ir, Os, and Ru) accumulation in ancient polar archives have been argued to trace cosmic dust and "smoke" from larger meteors but the PGE concentration data lack specificity. For example, the extent to which the terrestrial volcanism/dust has contributed to the PGE inventory of polar ice cannot be readily evaluated. Since the Os isotope compositions (187Os/188Os ratio) of the terrestrial and extraterrestrial sources are distinctly different from each other, the PGE concentrations when combined with Os isotope composition have the potential to untangle contributions from these sources. Platinum group element concentration determinations in polar ice cores are highly challenging due to their extremely low concentrations (down to 10-15 g/g or fg/g). Here, a new procedure is presented that allows PGEs and Os isotope compositions to be determined from a ~50 g sample of polar ice. Decontaminated ice-melt is spiked with 101Ru, 106Pd, 190Os, 191Ir, and 198Pt and frozen at -20 °C in quartz-glass ampoules. A mixture of purified HNO3 and H2O2 is then added and the sample is heated to 300 °C at 128bar using a High Pressure Asher. This allows all spikes to be equilibrated with the sample PGEs and all Os species are oxidized to OsO4. The resulting OsO4 is extracted using distillation, purified, and measured using negative thermal ionization mass spectrometry. PGEs are then separated and purified using two stage column chromatography and their concentrations determined by isotope dilution using a triple quadruople inductively coupled plasma mass spectrometer coupled to an Apex de-solvation nebulizer. The developed method was applied to modern Greenland firn and snow. The PGE concentrations of the firn are 4.0 fg/g for Ir, 20 fg/g for Ru, 590 fg/g for Pt, 38 fg/g for Pd, and 1.3 fg/g for Os, while those of the snow are 3.0 fg/g for Ir, 53 fg/g for Ru, 360 fg/g for Pt, 32 fg/g for Pd, and 0.4 fg/g for Os, respectively. A comparison

  9. Separation of drainage runoff during rainfall-runoff episodes using the stable isotope method and drainage water temperature

    NASA Astrophysics Data System (ADS)

    Zajíček, Antonín; Kvítek, Tomáš; Pomije, Tomáš

    2014-05-01

    Stabile isotopes of 2H 18O and drainage water temperature were used as natural tracers for separation rainfall-runoff event hydrograph on several tile drained catchments located in Bohemian-Moravian Highland, Czech Republic. Small agricultural catchments with drainage systems built in slopes are typical for foothill areas in the Czech and Moravian highland. Often without permanent surface runoff, the drainage systems represent an important portion of runoff and nitrogen leaching out of the catchment. The knowledge of the drainage runoff formation and the origin of its components are prerequisites for formulation of measures leading to improvement of the drainage water quality and reduction of nutrient leaching from the drained catchments. The results have proved presence of event water in the drainage runoff during rainfall-runoff events. The proportion of event water observed in the drainage runoff varied between 15 - 60 % in the summer events and 0 - 50 % in winter events, while the sudden water temperature change was between 0,1 - 4,2 °C (2 - 35 %). The comparison of isotope separation of the drainage runoff and monitoring the drainage water temperature have demonstrated that in all cases of event water detected in the runoff, a rapid change in the drainage water temperature was observed as well. The portion of event water in the runoff grows with the growing change in water temperature. Using component mixing model, it was demonstrated that water temperature can be successfully used at least as a qualitative and with some degree of inaccuracy as a quantitative tracer as well. The drawback of the non-conservative character of this tracer is compensated by both its economic and technical accessibility. The separation results also resemble results of separations at small streams. Together with a similarly high speed of the discharge reaction to beginning of precipitation, it is obvious that the mechanism of surface runoff formation and drainage runoff formation

  10. Separating the Wheat from the Chaff in Middle School Literature Study Guides.

    ERIC Educational Resources Information Center

    Radencich, Marguerite Cogorno

    1997-01-01

    Describes and discusses an evaluation procedure for middle school literature study guides that uses a combination of three frameworks: J. Langer's model of literature study, H. Gardner's theory of multiple intelligences, and B. Cambourne's conditions for learning. Uses the evaluation procedure to compare two study guides for a historical fiction…

  11. Compositional and isotopic diversity in MORB crystal cargoes: the differing influence of crustal and mantle processes on separate phase populations

    NASA Astrophysics Data System (ADS)

    Winpenny, B.; Maclennan, J.

    2010-12-01

    trace elements and Sr and O isotope ratios in compositionally zoned crystals. By comparing the known liquid compositions of Krafla and Borgarhraun with feldspar trace element and isotopic data, we aim to determine whether the plagioclase crystals are of a) magmatic or b) hydrothermal origin, and if magmatic, whether the crystals are cognate to the carrier melt or of xenocrystic origin. Preliminary O and Sr isotope data suggest that a sub-population of plagioclase crystals from both flows has undergone direct hydrothermal interaction, with others having crystallised from melts contaminated by altered crustal material. Additionally, some of the aspects of the current plagioclase dataset can be explained by concurrent mixing and crystallisation of variable primary mantle melt compositions, in sympathy with the clinopyroxene and olivine data. The contrasting and possibly diverse origins for the chemical and isotopic heterogeneity in separate crystal phase populations in these basaltic flows highlight the need for careful characterisation of individual crystal phases when making inferences from bulk isotopic or chemical analyses on MORB phenocrysts.

  12. Pygmy dipole strength close to particle-separation energies --The case of the Mo isotopes

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Grosse, E.; Erhard, M.; Junghans, A.; Kosev, K.; Schilling, K.-D.; Schwengner, R.; Wagner, A.

    2006-03-01

    The distribution of electromagnetic dipole strength in 92, 98, 100Mo has been investigated by photon scattering using bremsstrahlung from the new ELBE facility. The experimental data for well-separated nuclear resonances indicate a transition from a regular to a chaotic behaviour above 4MeV of excitation energy. As the strength distributions follow a Porter-Thomas distribution much of the dipole strength is found in weak and in unresolved resonances appearing as fluctuating cross section. An analysis of this quasi-continuum --here applied to nuclear resonance fluorescence in a novel way-- delivers dipole strength functions, which are combining smoothly to those obtained from (γ, n) data. Enhancements at 6.5MeV and at ˜ 9MeV are linked to the pygmy dipole resonances postulated to occur in heavy nuclei.

  13. Stable isotope and trace metal compositions of Australian prawns as a guide to authenticity and wholesomeness.

    PubMed

    Carter, J F; Tinggi, U; Yang, X; Fry, B

    2015-03-01

    This research has explored the potential of stable isotope and trace metal profiles to distinguish Australian prawns from prawns imported from neighbouring Asian countries. Australian prawns were collected mostly from the Brisbane area. Strong differences in Australian vs. imported prawns were evident from both the isotope and trace element data, with the differences most likely occurring because imported prawns are typically reared in aquaculture facilities and frozen prior to sale in Australia. The aquaculture origins are characterised by comparatively; low δHVSMOW, δ(13)CVPDB values, low concentrations of arsenic, zinc and potassium, and high water contents (>80%). Relatively high arsenic and cadmium contents were found within Australian prawns, but the concentrations did not exceed local human health guidelines.

  14. Proceedings of the XVIIth International Conference on Electromagnetic Isotope Separators and Related Topics (EMIS2015), Grand Rapids, MI, U.S.A., 11-15 May 2015

    NASA Astrophysics Data System (ADS)

    Bollen, Georg; Mittig, Wolfgang; Morrissey, Dave; Schwarz, Stefan; Villari, Antonio

    2016-06-01

    The 17th International Conference on Electromagnetic Isotope Separators and Related Topics (EMIS-2015) was held in Grand Rapids, Michigan, in the United States, from May 11th to 15th, 2015. The EMIS-2015 conference was hosted by Michigan State University. The present volume contains the proceedings of the event.

  15. The Precise Determination of Cd Isotope Ratio in Geological Samples by MC-ICP-MS with Ion Exchange Separation

    NASA Astrophysics Data System (ADS)

    Du, C.; Hu, S.; Wang, D.; Jin, L.; Guo, W.

    2014-12-01

    Cadmium (Cd) is a trace element which occurs at μg g-1 level abundances in the crust. Cd isotopes have great prospects in the study of the cosmogony, the trace of anthropogenic sources, the micronutrient cycling and the ocean productivity. This study develops an optimized technique for the precise and accurate determination of Cd isotopic compositions. Cd was separated from the matrix by elution with AG-MP-1 anionic exchange chromatographic resin. The matrix elements (K, Na, Ca, Al, Fe, and Mg etc.), polyatomic interfered elements (Ge, Ga, Zr, Nb, Ru, and Mo), and isobaric interfered elements (In, Pd and most of Sn) were eluted using HCl with gradient descent concentrations (2, 0.3, 0.06, 0.012 and 0.0012 mol L-1). The same elution procedure was repeated to eliminate the residuel Sn (Sn/Cd < 0.018). The collected Cd was analyzed using MC-ICP-MS, in which the instrumental mass fractionation was controlled by a "sample-standard bracketing" technique. The recovery of Cd larger than 96.85%, and the δ114/110Cd are in the range of -1.43~+0.20‰ for ten geological reference materials (GSD-3a, GSD-5a, GSD-7a, GSD-6, GSD-9, GSD-10, GSD-11, GSD-12, GSD-23, and GSS-1). The δ114/110Cd obtained for GSS-1 soil sample relative to the NIST SRM 3108 Cd solution was 0.20, which was coherent with the literature values (0.08±0.23). This method had a precision of 0.001~0.002% (RSD), an error range of 0.06~0.14 (δ114/110Cd, 2σ), and a long-term reproducibility of 0.12 (δ114/110Cd, 2σ).

  16. Experimental equipment for an advanced ISOL facility[Isotope Separation On-Line Facility

    SciTech Connect

    Baktash, C.; Lee, I.Y.; Rehm, K.E.

    1999-03-01

    This report summarizes the proceedings and recommendations of the Workshop on the Experimental Equipment for an Advanced ISOL Facility which was held at Lawrence Berkeley National Laboratory on July 22--25, 1998. The purpose of this workshop was to discuss the performance requirements, manpower and cost estimates, as well as a schedule of the experimental equipment needed to fully exploit the new physics which can be studied at an advanced ISOL facility. An overview of the new physics opportunities that would be provided by such a facility has been presented in the White Paper that was issued following the Columbus Meeting. The reactions and experimental techniques discussed in the Columbus White Paper served as a guideline for the formulation of the detector needs at the Berkeley Workshop. As outlined a new ISOL facility with intense, high-quality beams of radioactive nuclei would provide exciting new research opportunities in the areas of: the nature of nucleonic matter; the origin of the elements; and tests of the Standard Model. After an introductory section, the following equipment is discussed: gamma-ray detectors; recoil separators; magnetic spectrographs; particle detectors; targets; and apparatus using non-accelerated beams.

  17. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    NASA Astrophysics Data System (ADS)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0–20, 20–40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0–20 cm = 1492.4 gC m2 and 20–40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  18. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    PubMed Central

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0–20, 20–40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0–20 cm = 1492.4 gC m2 and 20–40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C. PMID:26750143

  19. Characterization of Diesel Fuel by Chemical Separation Combined with Capillary Gas Chromatography (GC) Isotope Ratio Mass Spectrometry (IRMS)

    SciTech Connect

    Harvey, Scott D.; Jarman, Kristin H.; Moran, James J.; Sorensen, Christina M.; Wright, Bob W.

    2011-09-15

    The purpose of this study was to perform a preliminary investigation of compound-specific isotope analysis (CSIA) of diesel fuels to evaluate whether the technique could distinguish between the diesel samples from different sources/locations. The ability to differentiate or correlate diesel samples could be valuable for detecting fuel tax evasion schemes. Two fractionation techniques were used to isolate the n-alkanes from the fuel. Both δ13C and δD values for the n-alkanes were then determined by CSIA in each sample. Plots of δD versus δ13C with sample n-alkane points connected in order of increasing carbon number gave well separated clusters with characteristic shapes for each sample. Principal components analysis (PCA) with δ13C, δD, or combined δ13C and δD data on the yielded scores plots that could clearly differentiate the samples, thereby demonstrating the potential of this approach for fingerprinting fuel samples using the δ13C and δD values.

  20. Problem of soot aggregates separation and purification for Carbon isotopic composition analyses - burning experiment and real black layers from speleothems examples

    NASA Astrophysics Data System (ADS)

    Hercman, Helena; Zawidzki, Pawel; Majewska, Agata

    2015-04-01

    Burning products are often used as an indicator of fire or prehistoric men activities. When it consists of macroscopically visible black layer it may be studied by different methods. When it is dispersed within sediment it is necessary to apply method for burning product separation. Soot aggregates as a result of incomplete combustion of organic materials are most reliable indication of burning. Size of soot particles is too small to observe by optical microscopy. There are two main advantages of application of transmission electron microscopy (TEM) for investigations of samples formed as a result of organic materials (like wood) combustion. First, it makes possible to investigate not only morphology but also its interior structure. The carbon layers arrangement is characteristic for particles obtained from combustion processes, and it directly confirm that these particles were formed that way. And second, analysis of chemical composition using of EDS spectroscopy in transmission microscope are precise and it spatial resolution is about a few nanometers. Burning chamber for wood burning experiments was constructed. It allows wood burning with controlling of burning temperature, carbon isotopic composition in carbon dioxide of burning atmosphere and carbon dioxide originated during burning. Burning products are collected on the plates with controlling of plates material, temperature and distance from flame. Two types of samples were studied. The first type of samples consisted the products of recent wood burning. The second type of samples consisted of black layers collected from speleothems. Soot aggregates were chemically separated from other burning products collected on plates. Process of chemical separation and purity of soot material were tested by TEM observations. Isotopic carbon composition at each step of soot separation as well as original wood fragments was analysed at the Isotopic Laboratory for Dating and Palaeoenvironment Studies, Polish Academy of

  1. ELECTROMAGNETIC SEPARATION OF ISOTOPES

    DOEpatents

    Barnes, S.W.; Centrell, C.M.

    1960-02-01

    An improved calutron receiver is described having two entrance slots leading to two electrically isolated pockets. A wall of the pocket intended to receive the heavier ions defines one side of the entrance slot to the other pocket and it is so constructed and arranged that the two sides of the wall are substantially equally exposed to the respective ion beams. Thus the per cent rejection of material entering the two entrance slots is the same for each slot.

  2. Upgrade of the resonance ionization laser ion source at ISOLDE on-line isotope separation facility: New lasers and new ion beamsa)

    NASA Astrophysics Data System (ADS)

    Fedosseev, V. N.; Berg, L.-E.; Fedorov, D. V.; Fink, D.; Launila, O. J.; Losito, R.; Marsh, B. A.; Rossel, R. E.; Rothe, S.; Seliverstov, M. D.; Sjödin, A. M.; Wendt, K. D. A.

    2012-02-01

    The resonance ionization laser ion source (RILIS) produces beams for the majority of experiments at the ISOLDE on-line isotope separator. A substantial improvement in RILIS performance has been achieved through a series of upgrade steps: replacement of the copper vapor lasers by a Nd:YAG laser; replacement of the old homemade dye lasers by new commercial dye lasers; installation of a complementary Ti:Sapphire laser system. The combined dye and Ti:Sapphire laser system with harmonics is capable of generating beams at any wavelength in the range of 210-950 nm. In total, isotopes of 31 different elements have been selectively laser-ionized and separated at ISOLDE, including recently developed beams of samarium, praseodymium, polonium, and astatine.

  3. The innate responses of bumble bees to flower patterns: separating the nectar guide from the nectary changes bee movements and search time

    NASA Astrophysics Data System (ADS)

    Goodale, Eben; Kim, Edward; Nabors, Annika; Henrichon, Sara; Nieh, James C.

    2014-06-01

    Nectar guides can enhance pollinator efficiency and plant fitness by allowing pollinators to more rapidly find and remember the location of floral nectar. We tested if a radiating nectar guide around a nectary would enhance the ability of naïve bumble bee foragers to find nectar. Most experiments that test nectar guide efficacy, specifically radiating linear guides, have used guides positioned around the center of a radially symmetric flower, where nectaries are often found. However, the flower center may be intrinsically attractive. We therefore used an off-center guide and nectary and compared "conjunct" feeders with a nectar guide surrounding the nectary to "disjunct" feeders with a nectar guide separated from the nectary. We focused on the innate response of novice bee foragers that had never previously visited such feeders. We hypothesized that a disjunct nectar guide would conflict with the visual information provided by the nectary and negatively affect foraging. Approximately, equal numbers of bumble bees ( Bombus impatiens) found nectar on both feeder types. On disjunct feeders, however, unsuccessful foragers spent significantly more time (on average 1.6-fold longer) searching for nectar than any other forager group. Successful foragers on disjunct feeders approached these feeders from random directions unlike successful foragers on conjunct feeders, which preferentially approached the combined nectary and nectar guide. Thus, the nectary and a surrounding nectar guide can be considered a combination of two signals that attract naïve foragers even when not in the floral center.

  4. Determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using radiochemical separation combined with radiometric and mass spectrometric measurements.

    PubMed

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin; Pan, Shaoming; Roos, Per

    2014-02-01

    This paper reports an analytical method for the determination of plutonium isotopes ((238)Pu, (239)Pu, (240)Pu, (241)Pu) in environmental samples using anion exchange chromatography in combination with extraction chromatography for chemical separation of Pu. Both radiometric methods (liquid scintillation counting and alpha spectrometry) and inductively coupled plasma mass spectrometry (ICP-MS) were applied for the measurement of plutonium isotopes. The decontamination factors for uranium were significantly improved up to 7.5 × 10(5) for 20 g soil compared to the level reported in the literature, this is critical for the measurement of plutonium isotopes using mass spectrometric technique. Although the chemical yield of Pu in the entire procedure is about 55%, the analytical results of IAEA soil 6 and IAEA-367 in this work are in a good agreement with the values reported in the literature or reference values, revealing that the developed method for plutonium determination in environmental samples is reliable. The measurement results of (239+240)Pu by alpha spectrometry agreed very well with the sum of (239)Pu and (240)Pu measured by ICP-MS. ICP-MS can not only measure (239)Pu and (240)Pu separately but also (241)Pu. However, it is impossible to measure (238)Pu using ICP-MS in environmental samples even a decontamination factor as high as 10(6) for uranium was obtained by chemical separation.

  5. Chromatographic Separation of Cd from Plants via Anion-Exchange Resin for an Isotope Determination by Multiple Collector ICP-MS.

    PubMed

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Peters, Marc; Yang, Junxing; Tian, Liyan; Han, Xiaokun

    2017-01-01

    In this study, key factors affecting the chromatographic separation of Cd from plants, such as the resin column, digestion and purification procedures, were experimentally investigated. A technique for separating Cd from plant samples based on single ion-exchange chromatography has been developed, which is suitable for the high-precision analysis of Cd isotopes by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The robustness of the technique was assessed by replicate analyses of Cd standard solutions and plant samples. The Cd yields of the whole separation process were higher than 95%, and the (114/110)Cd values of three Cd second standard solutions (Münster Cd, Spex Cd, Spex-1 Cd solutions) relative to the NIST SRM 3108 were measured accurately, which enabled the comparisons of Cd isotope results obtained in other laboratories. Hence, stable Cd isotope analyses represent a powerful tool for fingerprinting specific Cd sources and/or examining biogeochemical reactions in ecological and environmental systems.

  6. GUESSmix-guided optimization of elution-extrusion counter-current separations.

    PubMed

    Friesen, J Brent; Pauli, Guido F

    2009-05-08

    Rational strategies for the optimization of separations are vital to any chromatographic technique. In counter-current separations (CS), once a suitable solvent system is selected for a given separation, the operator is faced with the task of optimizing the separation through the manipulation of those adjustable operation parameters allowed for by the current CS technology. This study employed a mixture of 21 natural products of varying polarity, molecular mass, and functionality, termed the GUESSmix, as a tool to assess the effectiveness of optimization strategies. The behavior of the GUESSmix was observed in the hexane/ethyl acetate/methanol/water 4:6:4:6 (HEMWat +3) solvent system. The effect of operation parameters on both the elution and extrusion stages of a recently introduced CS methodology, termed elution-extrusion counter-current chromatography (EECCC), was investigated. The resulting chromatograms were plotted with K-based reciprocal symmetry plots (ReS and ReSS), which allow comparison of the K values of significant peaks and assessment of resolution of eluting compounds in the interval 0< or =K< or =infinity. The operation parameters studied were: (1) the effect of temperature controlled water circulation around the centrifuge; (2) the combination of flow rate and revolution speed; (3) sample loading capacity; (4) the direction of rotation either agreeing with or opposing the direction of coil winding; (5) injection before equilibration, a practice that saves operator time and reduces solvent consumption. The GUESSmix was found to be a highly useful reference mixture to compare and contrast stationary phase retention volume ratios, resolution, K-values, peak shapes, and extrusion characteristics between CS experiments. EECCC is shown to be a robust technique that may be enhanced with appropriate temperature, rpm, flow rate, sample loading, direction of rotation, and injection timing. Plotting ReS[S] chromatograms enables systematic study of CS

  7. Guide to CO{sub 2} separations in imidazolium-based room-temperature ionic liquids

    SciTech Connect

    Bara, J.E.; Carlisle, T.K.; Gabriel, C.J.; Camper, D.; Finotello, A.; Gin, D.L.; Noble, R.D.

    2009-03-18

    Room-temperature ionic liquids (RTILs) are nonvolatile, tunable solvents. The solubilities of gases, particularly CO{sub 2}, N{sub 2}, and CH{sub 4}, have been studied in a number of RTILs. Process temperature and the chemical structures of the cation and anion have significant impacts on gas solubility and gas pair selectivity. Models based on regular solution theory and group contributions are useful to predict and explain CO{sub 2} solubility and selectivity in imidazolium-based RTILs. In addition to their role as a physical solvent, RTILs might also be used in supported ionic liquid membranes (SILMs) as a highly permeable and selective transport medium. Performance data for SILMs indicates that they exhibit large permeabilities as well as CO{sub 2}/N{sub 2} selectivities that outperform many polymer membranes. Furthermore, the greatest potential of RTILs for CO{sub 2} separations might lie in their ability to chemically capture CO{sub 2} when used in combination with amines. Amines can be tethered to the cation or the anion, or dissolved in RTILs, providing a wide range of chemical solvents for CO{sub 2} capture. However, despite all of their promising features, RTILs do have drawbacks to use in CO{sub 2} separations, which have been overlooked as appropriate comparisons of RTILs to common organic solvents and polymers have not been reported. A thorough summary of the capabilities-and limitations-of imidazolium-based RTILs in CO{sub 2}-based separations with respect to a variety of materials is thus provided.

  8. Preliminary results from a microvolume, dynamically heated analytical column for preconcentration and separation of simple gases prior to stable isotopic analysis

    NASA Astrophysics Data System (ADS)

    Panetta, Robert James; Seed, Mike

    2016-04-01

    Stable isotope applications that call for preconcentration (i.e., greenhouse gas measurements, small carbonate samples, etc.) universally call for cryogenic fluids such as liquid nitrogen, dry ice slurries, or expensive external recirculation chillers. This adds significant complexity, first and foremost in the requirements to store and handle such dangerous materials. A second layer of complexity is the instrument itself - with mechanisms to physically move either coolant around the trap, or move a trap in or out of the coolant. Not to mention design requirements for hardware that can safely isolate the fluid from other sensitive areas. In an effort to simplify the isotopic analysis of gases requiring preconcentration, we have developed a new separation technology, UltiTrapTM (patent pending), which leverage's the proprietary Advanced Purge & Trap (APT) Technology employed in elemental analysers from Elementar Analysensysteme GmbH products. UltiTrapTM has been specially developed as a micro volume, dynamically heated GC separation column. The introduction of solid-state cooling technology enables sub-zero temperatures without cryogenics or refrigerants, eliminates all moving parts, and increases analytical longevity due to no boiling losses of coolant . This new technology makes it possible for the system to be deployed as both a focussing device and as a gas separation device. Initial data on synthetic gas mixtures (CO2/CH4/N2O in air), and real-world applications including long-term room air and a comparison between carbonated waters of different origins show excellent agreement with previous technologies.

  9. Effective Boson Number- A New Approach for Predicting Separation Energies with the IBM1, Applied to Zr, Kr, Sr isotopes near A = 100

    NASA Astrophysics Data System (ADS)

    Paul, Nancy; van Isacker, Pieter; García Ramos, José Enrique; Aprahamian, Ani

    2011-10-01

    This work uses effective boson numbers in the Interacting Boson Model (IBM1) to predict two neutron separation energies for neutron-rich zirconium, strontium, and krypton isotopes., We determine the functional forms of binding energy and excitation energies as a function of boson number for a given choice of IBM parameters that give a good overall description of the experimental spectra of the isotopic chain. The energy of the first excited 2+ level is then used to extract an effective boson number for a given nucleus, that is in turn used to calculate the separation energies. This method accounts for complex interactions among valence nucleons around magic and semi- magic nuclei and successfully predicts the phase transitional signature in separation energies around A=100 for 92-108Zr, 90-104Sr, and 86-96Kr Supported by the NSF under contract PHY0758100, the Joint Institute for Nuclear Astrophysics grant PHY0822648, University of Notre Dame Nanovic Institute, Glynn Family Honors Program, Center for Undergraduate Scholarly Engagement.

  10. A fully automated system with online sample loading, isotope dimethyl labeling and multidimensional separation for high-throughput quantitative proteome analysis.

    PubMed

    Wang, Fangjun; Chen, Rui; Zhu, Jun; Sun, Deguang; Song, Chunxia; Wu, Yifeng; Ye, Mingliang; Wang, Liming; Zou, Hanfa

    2010-04-01

    Multidimensional separation is often applied for large-scale qualitative and quantitative proteome analysis. A fully automated system with integration of a reversed phase-strong cation exchange (RP-SCX) biphasic trap column into vented sample injection system was developed to realize online sample loading, isotope dimethyl labeling and online multidimensional separation of the proteome samples. Comparing to conventionally manual isotope labeling and off-line fractionation technologies, this system is fully automated and time-saving, which is benefit for improving the quantification reproducibility and accuracy. As phosphate SCX monolith was integrated into the biphasic trap column, high sample injection flow rate and high-resolution stepwise fractionation could be easily achieved. Approximately 1000 proteins could be quantified in approximately 30 h proteome analysis, and the proteome coverage of quantitative analysis can be further greatly improved by prolong the multidimensional separation time. This system was applied to analyze the different protein expression level of HCC and normal human liver tissues. After three times replicated analysis, finally 94 up-regulated and 249 down-regulated (HCC/Normal) proteins were successfully obtained. These significantly regulated proteins are widely validated by both gene and proteins expression studies previously. Such as some enzymes involved in urea cycle, methylation cycle and fatty acids catabolism in liver were all observed down-regulated.

  11. A Guide for Assessing Biodegradation and Source Identification of Organic Groundwater Contaminants Using Compound Specific Isotope Analysis (CSIA)

    EPA Science Inventory

    When organic contaminants are degraded in the environment, the ratio of stable isotopes will often change, and the extent of degradation can be recognized and predicted from the change in the ratio of stable isotopes. Recent advances in analytical chemistry make it possible to p...

  12. Near-infrared dye bound albumin with separated imaging and therapy wavelength channels for imaging-guided photothermal therapy.

    PubMed

    Chen, Qian; Wang, Chao; Zhan, Zhixiong; He, Weiwei; Cheng, Zhenping; Li, Youyong; Liu, Zhuang

    2014-09-01

    Development of theranostic agent for imaging-guided photothermal therapy has been of great interest in the field of nanomedicine. However, if fluorescent imaging and photothermal ablation are conducted with the same wavelength of light, the requirements of the agent's quantum yield (QY) for imaging and therapy are controversial. In this work, our synthesized near-infrared dye, IR825, is bound with human serum albumin (HSA), forming a HSA-IR825 complex with greatly enhanced fluorescence under 600 nm excitation by as much as 100 folds compared to that of free IR825, together with a rather high absorbance but low fluorescence QY at 808 nm. Since high QY that is required for fluorescence imaging would result in reduced photothermal conversion efficiency, the unique optical behavior of HSA-IR825 enables imaging and photothermal therapy at separated wavelengths both with optimized performances. We thus use HSA-IR825 for imaging-guided photothermal therapy in an animal tumor model. As revealed by in vivo fluorescence imaging, HSA-IR825 upon intravenous injection shows high tumor uptake likely owing to the enhanced permeability and retention effect, together with low levels of retentions in other organs. While HSA is an abundant protein in human serum, IR825 is able to be excreted by renal excretion as evidenced by high-performance liquid chromatography (HPLC). In vivo tumor treatment experiment is finally carried out with HSA-IR825, achieving 100% of tumor ablation in mice using a rather low dose of IR825. Our work presents a safe, simple, yet imageable photothermal nanoprobe, promising for future clinical translation in cancer treatment.

  13. Selective IR multiphoton dissociation of molecules in a pulsed gas-dynamically cooled molecular flow interacting with a solid surface as an alternative to low-energy methods of molecular laser isotope separation

    NASA Astrophysics Data System (ADS)

    Makarov, G. N.; Petin, A. N.

    2016-03-01

    We report the results of studies on the isotope-selective infrared multiphoton dissociation (IR MFD) of SF6 and CF3I molecules in a pulsed, gas-dynamically cooled molecular flow interacting with a solid surface. The productivity of this method in the conditions of a specific experiment (by the example of SF6 molecules) is evaluated. A number of low-energy methods of molecular laser isotope separation based on the use of infrared lasers for selective excitation of molecules are analysed and their productivity is estimated. The methods are compared with those of selective dissociation of molecules in the flow interacting with a surface. The advantages of this method compared to the low-energy methods of molecular laser isotope separation and the IR MPD method in the unperturbed jets and flows are shown. It is concluded that this method could be a promising alternative to the low-energy methods of molecular laser isotope separation.

  14. A First Look at Graphite Grains from Orgueil: Morphology, Carbon, Nitrogen and Neon Isotopic Compositions of Individual, Chemically Separated Grains

    NASA Technical Reports Server (NTRS)

    Pravdivtseva, O.; Zinner, E.; Meshik, A. P.; Hohenberg, C. M.; Walker, R. W.

    2004-01-01

    Presolar graphite in Murchison has been extensively studied. It is characterized by a unique Ne isotopic composition, known as the Ne-E(L) component. According to studies by Huss and Lewis, the concentration of Ne-E(L) in Orgueil is about one order of magnitude higher than in Murchison, when normalized to the matrix. This could be due to a higher presolar graphite abundance in Orgueil, or due to a higher Ne-E concentrations per grain. The Ne isotopic compositions in individual presolar graphite grains from Murchison have been measured before. It was shown, that a third of the grains have detectable excesses in 22Ne, characteristic of the Ne-E(L) component. One grain in a hundred had a Ne-22 concentration two orders of magnitude higher than blank.

  15. Large volume injection in ion chromatography Separation of rubidium and strontium for on-line inductively coupled plasma mass spectrometry determination of strontium isotope ratios.

    PubMed

    García-Ruiz, Silvia; Moldovan, Mariella; García Alonso, J Ignacio

    2007-05-18

    Large volume injection, up to 5 mL, was evaluated and optimised for the on-line ion chromatographic separation of Rb and Sr before ICP-MS measurement of Sr isotope ratios. Flat-topped chromatographic peaks, ideally suited for multicollector ICP-MS isotope ratio measurements, could be obtained when the composition of the mobile phase (nitric acid and 18-crown-6 ether) was identical to the matrix of the sample. Under those conditions rubidium eluted at the dead volume of the column while strontium produced a flat-topped transient signal with several minutes of stable plateau. On-line data acquisition during several minutes at the plateau of Sr signal allowed high precision Sr isotope ratio measurement. The developed procedure was evaluated for Sr isotope ratio measurements on different types of samples, including cider, apples, apple leaves, and soil extracts, in the frame of a long-term project aiming at origin authentication using strontium isotope ratio measurements. It was observed that sample matrix caused broadening of the strontium chromatographic peak and loss of flat-topped peak profile. Under those circumstances the addition of the complexing crown-ether 18-crown-6 both to samples and chromatographic eluent provided two distinct advantages. First, a drastic increase in the retention of strontium was observed which could be modulated by increasing the concentration of nitric acid in the eluent up to 900 mM. This increase in the eluent HNO(3) concentration allowed the application of the method to acid soil digests and other high acidity samples. Second, the matrix of the sample did not affect any more the chromatographic peak profile and similar chromatographic separations could be obtained for samples and standards maintaining the flat-topped Sr peak profile. Sample preparation consisted of a simple 1:10 dilution of the cider or pre-treated solid samples by adding HNO(3) (900 mM) and 18-crown-6 ether (5mM) to obtain similar composition in the sample solution

  16. Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research

    SciTech Connect

    Redondo, L. M.; Canacsinh, H.; Ferrao, N.; Mendes, C.; Silva, J. Fernando; Soares, R.; Schipper, J.; Fowler, A.

    2010-07-15

    A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

  17. Bioactivity-guided Separation of the Active Compounds in Acacia pennata Responsible for the Prevention of Alzheimer's Disease.

    PubMed

    Lomarat, Pattamapan; Chancharunee, Sirirat; Anantachoke, Natthinee; Kitphati, Worawan; Sripha, Kittisak; Bunyapraphatsara, Nuntavan

    2015-08-01

    The objective of this study was to evaluate the health benefits of plants used in Thai food, specifically Acacia pennata Willd., in Alzheimer's prevention. A. pennata twigs strongly inhibited β-amyloid aggregation. Bioactivity-guided separation of the active fractions yielded six known compounds, tetracosane (1), 1-(heptyloxy)-octadecane (2), methyl tridecanoate (3), arborinone (4), confertamide A (5) and 4-hydroxy-1-methyl-pyrrolidin-2-carboxylic acid (6). The structures were determined by spectroscopic analysis. Biological testing revealed that tetracosane (1) was the most potent inhibitor of β-amyloid aggregation, followed by 1-(heptyloxy)-octadecane (2) with IC50 values of 0.4 and 12.3 μM. Methyl tridecanoate (3), arborinone (4) and 4-hydroxy-1-methyl-pyrrolidin-2-carboxylic acid (6) moderately inhibited β-amyloid aggregation. In addition, tetracosane (1) and methyl tridecanoate (3) weakly inhibited acetylcholinesterase (AChE). These results suggested that the effect of A. pennata on Alzheimer's disease was likely due to the inhibition of β-amyloid aggregation. Thus A. pennata may be beneficial for Alzheimer's prevention.

  18. Mantle Helium and Carbon Isotopes in Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon: Evidence for Renewed Volcanic Activity or a Long Term Steady State System?

    USGS Publications Warehouse

    Van Soest, M. C.; Kennedy, B.M.; Evans, William C.; Mariner, R.H.

    2002-01-01

    Here we present the helium and carbon isotope results from the initial study of a fluid chemistry-monitoring program started in the summer of 2001 near the South Sister volcano in central Oregon. The Separation Creek area which is several miles due west of the volcano is the locus of strong crustal uplift currently occurring at a rate of 4-5 cm/yr (Wicks, et. al., 2001).Helium [RC/RA = 7.44 and 8.61 RA (RC/R A = (3He/4He)sample-. air corrected/(3He/4He)air))] and carbon (??13C = -11.59 to -9.03??? vs PDB) isotope data and CO2/3He (5 and 9 ?? 109) show that bubbling cold springs in the Separation Creek area near South Sister volcano carry a strong mantle signal, indicating the presence of fresh basaltic magma in the volcanic plumbing system. There is no evidence though, to directly relate this signal to the crustal uplift that is currently taking place in the area, which started in 1998. The geothermal system in the area is apparently much longer lived and shows no significant changes in chemistry compared to data from the early 1990s. Hot springs in the area, which are relatively far removed from the volcanic edifice, do not carry a strong mantle signal in helium isotope ratios (2.79 to 5.08 RA), unlike the cold springs, and also do not show any significant changes in helium isotope ratios compared to literature data for the same springs of over two decades ago. The cold springs of the Separation Creek area form a very diffuse but significant low temperature geothermal system, that should, due to its close vicinity to the center of up uplift, be more sensitive to changes in the deeper volcanic plumbing system than the far removed hot springs and therefore require much more study and consideration when dealing with volcano monitoring in the Cascade range or possibly with geothermal exploration in general.

  19. Using isotopes of dissolved inorganic carbon species and water to separate sources of recharge in a cave spring, northwestern Arkansas, USA Blowing Spring Cave

    USGS Publications Warehouse

    Knierim, Katherine J.; Pollock, Erik; Hays, Phillip D.

    2013-01-01

    Blowing Spring Cave in northwestern Arkansas is representative of cave systems in the karst of the Ozark Plateaus, and stable isotopes of water (δ18O and δ2H) and inorganic carbon (δ13C) were used to quantify soil-water, bedrock-matrix water, and precipitation contributions to cave-spring flow during storm events to understand controls on cave water quality. Water samples from recharge-zone soils and the cave were collected from March to May 2012 to implement a multicomponent hydrograph separation approach using δ18O and δ2H of water and dissolved inorganic carbon (δ13C–DIC). During baseflow, median δ2H and δ18O compositions were –41.6‰ and –6.2‰ for soil water and were –37.2‰ and –5.9‰ for cave water, respectively. Median DIC concentrations for soil and cave waters were 1.8 mg/L and 25.0 mg/L, respectively, and median δ13C–DIC compositions were –19.9‰ and –14.3‰, respectively. During a March storm event, 12.2 cm of precipitation fell over 82 h and discharge increased from 0.01 to 0.59 m3/s. The isotopic composition of precipitation varied throughout the storm event because of rainout, a change of 50‰ and 10‰ for δ2H and δ18O was observed, respectively. Although, at the spring, δ2H and δ18O only changed by approximately 3‰ and 1‰, respectively. The isotopic compositions of precipitation and pre-event (i.e., soil and bedrock matrix) water were isotopically similar and the two-component hydrograph separation was inaccurate, either overestimating (>100%) or underestimating (<0%) the precipitation contribution to the spring. During the storm event, spring DIC and δ13C–DIC decreased to a minimum of 8.6 mg/L and –16.2‰, respectively. If the contribution from precipitation was assumed to be zero, soil water was found to contribute between 23 to 72% of the total volume of discharge. Although the assumption of negligible contributions from precipitation is unrealistic, especially in karst systems where rapid flow

  20. Spatial separation of groundwater flow paths from a multi-flow system by a simple mixing model using stable isotopes of oxygen and hydrogen as natural tracers

    NASA Astrophysics Data System (ADS)

    Nakaya, Shinji; Uesugi, Kenji; Motodate, Yusuke; Ohmiya, Isao; Komiya, Hiroyuki; Masuda, Harue; Kusakabe, Minoru

    2007-09-01

    Stable isotopes of oxygen and hydrogen have the potential to serve as tracers for both source and flow paths in a groundwater system. The ratios of stable isotopes of oxygen (δ18O) and hydrogen (δD) can be used as natural tracer parameters to separate multiflow groundwater paths by applying a simple inversion analysis method to determine the differences between observed and calculated δ18O and δD data in a simple mixing model. The model presented here assumes that the distribution of natural tracers in the steady state is governed by simple mixing between flow paths with a normal distribution of flow rate. When the inversion analysis and simple mixing model were applied to the multiflow system of the Matsumoto Basin, which is surrounded by Japanese alpine ranges, the end-members of the relationship between observed δ18O and δD could be separated spatially into specific groundwater flow paths in the multiflow system of shallow and deep groundwater flow paths.

  1. Growth variability and stable isotope composition of two larval carangid fishes in the East Australian Current: The role of upwelling in the separation zone

    NASA Astrophysics Data System (ADS)

    Syahailatua, Augy; Taylor, Matthew D.; Suthers, Iain M.

    2011-03-01

    The larvae of two carangid fishes, silver trevally ( Pseudocaranx dentex) and yellowtail scad ( Trachurus novaezelandiae), were compared among coastal water masses and the East Australian Current (EAC). Samples followed a north to south gradient including a southern region of upwelling, generated as the EAC separated from the coast. Mean larval carangid densities were greater in the mixed layer (10-30 m) than the surface, but there was no difference between inshore and offshore stations or along latitudinal gradients. Overall, P. dentex recent larval growth over two days pre-capture was faster than T. novaezelandiae, and faster at inshore, coastal stations than in the EAC. Integrated larval growth rate (mm d -1) was usually faster at inshore stations for both species. T. novaezelandiae were enriched in both nitrogen (δ 15N) and carbon (δ 13C) stable isotopes relative to P. dentex. Larvae of both species captured within the upwelling region were enriched in δ 15N and depleted in δ 13C relative to other sites. Recent larval growth had a significant positive relationship with fluorescence (as a proxy of chlorophyll a biomass), and integrated larval growth rate had a significant positive relationship with fluorescence and larval isotope (δ 15N) composition. Recent and integrated growth of larval T. novaezelandiae and P. dentex was enhanced by EAC separation and upwelling, and also in coastal water; stimulated by food availability, and potentially through exploitation of a different trophic niche.

  2. First calibration measurements of an FTIR absorption spectroscopy system for liquid hydrogen isotopologues for the isotope separation system of fusion power plants

    SciTech Connect

    Groessle, R.; Beck, A.; Bornschein, B.; Fischer, S.; Kraus, A.; Mirz, S.; Rupp, S.

    2015-03-15

    Fusion facilities like ITER and DEMO will circulate huge amounts of deuterium and tritium in their fuel cycle with an estimated throughput of kg per hour. One important capability of these fuel cycles is to separate the hydrogen isotopologues (H{sub 2}, D{sub 2}, T{sub 2}, HD, HT, DT). For this purpose the Isotope Separation System (ISS), using cryogenic distillation, as part of the Tritium Enrichment Test Assembly (TRENTA) is under development at Tritium Laboratory Karlsruhe. Fourier transform infrared absorption spectroscopy (FTIR) has been selected to prove its capability for online monitoring of the tritium concentration in the liquid phase at the bottom of the distillation column of the ISS. The actual research-development work is focusing on the calibration of such a system. Two major issues are the identification of appropriate absorption lines and their dependence on the isotopic concentrations and composition. For this purpose the Tritium Absorption IR spectroscopy experiment has been set up as an extension of TRENTA. For calibration a Raman spectroscopy system is used. First measurements, with equilibrated mixtures of H{sub 2}, D{sub 2} and HD demonstrate that FTIR can be used for quantitative analysis of liquid hydro-gen isotopologues and reveal a nonlinear dependence of the integrated absorbance from the D{sub 2} concentration in the second vibrational branch of D{sub 2} FTIR spectra. (authors)

  3. Pre-Separation Guide

    DTIC Science & Technology

    1992-03-04

    hands; V Prosthetic appliances, sensory , Veteran Counseling and rehabilitative aids; To allow service members to better V Medical care for Dependents...Atlanta 30365 800-827-0634 San Diego 92108 telephone: local 881-1776 or telephone: local 297-8220 or 800-827-2039 Iowa 800-532-3811 210 Walnut St...STATE SERVED Federal Office Building IOWA MISSOURI Room 1 100 KANSAS NEBRASKA 911 Walnut Street Kansas City, MO 64106 Telephone: 816/426-3856 REGION

  4. A guide for the laboratory information management system (LIMS) for light stable isotopes--Versions 7 and 8

    USGS Publications Warehouse

    Coplen, Tyler B.

    2000-01-01

    The reliability and accuracy of isotopic data can be improved by utilizing database software to (i) store information about samples, (ii) store the results of mass spectrometric isotope-ratio analyses of samples, (iii) calculate analytical results using standardized algorithms stored in a database, (iv) normalize stable isotopic data to international scales using isotopic reference materials, and (v) generate multi-sheet paper templates for convenient sample loading of automated mass-spectrometer sample preparation manifolds. Such a database program, the Laboratory Information Management System (LIMS) for Light Stable Isotopes, is presented herein. Major benefits of this system include (i) a dramatic improvement in quality assurance, (ii) an increase in laboratory efficiency, (iii) a reduction in workload due to the elimination or reduction of retyping of data by laboratory personnel, and (iv) a decrease in errors in data reported to sample submitters. Such a database provides a complete record of when and how often laboratory reference materials have been analyzed and provides a record of what correction factors have been used through time. It provides an audit trail for laboratories. LIMS for Light Stable Isotopes is available for both Microsoft Office 97 Professional and Microsoft Office 2000 Professional as versions 7 and 8, respectively. Both source code (mdb file) and precompiled executable files (mde) are available. Numerous improvements have been made for continuous flow isotopic analysis in this version (specifically 7.13 for Microsoft Access 97 and 8.13 for Microsoft Access 2000). It is much easier to import isotopic results from Finnigan ISODAT worksheets, even worksheets on which corrections for amount of sample (linearity corrections) have been added. The capability to determine blank corrections using isotope mass balance from analyses of elemental analyzer samples has been added. It is now possible to calculate and apply drift corrections to isotopic

  5. Lead isotopes in iron and manganese oxide coatings and their use as an exploration guide for concealed mineralization

    USGS Publications Warehouse

    Gulson, B.L.; Church, S.E.; Mizon, K.J.; Meier, A.L.

    1992-01-01

    Lead isotopes from Fe and Mn oxides that coat stream pebbles from around the Mount Emmons porphyry molybdenum deposit in Colorado were studied to assess the feasibility of using Pb isotopes to detect concealed mineral deposits. The Fe/Mn oxide coatings were analyzed to determine their elemental concentrations using ICP-AES. The Pb isotope compositions of solutions from a selected suite of samples were measured, using both thermal ionization and ICP mass spectrometry, to compare results determined by the two analytical methods. Heavy mineral concentrates from the same sites were also analyzed to compare the Pb isotope compositions of the Fe/Mn coatings with those found in panned concentrates. The Fe/Mn and 206Pb/204Pb ratios of the oxide coatings are related to the lithology of the host rocks; Fe/Mn oxide coatings on pebbles of black shale have higher Fe/Mn values than do the coatings on either sandstone or igneous rocks. The shale host rocks have a more radiogenic signature (e.g. higher 206Pb/ 204Pb) than the sandstone or igneous host rocks. The Pb isotope data from sandstone and igneous hosts can detect concealed mineralized rock on both a regional and local scale, even though there are contributions from: (1) metals from the main-stage molybdenite ore deposit; (2) metals from the phyllic alteration zone which has a more radiogenic Pb isotope signature reflecting hydrothermal leaching of Pb from the Mancos Shale; (3) Pb-rich base metal veins with a highly variable Pb isotope signature; and (4) sedimentary country rocks which have a more radiogenic Pb isotope signature. An investigation of within-stream variation shows that the Pb isotope signature of the molybdenite ore zone is retained in the Fe/Mn oxide coatings and is not camouflaged by contributions from Pb-rich base-metal veins that crop out upstream. In another traverse, the Pb isotope data from Fe/Mn oxide coatings reflect a complex mixing of Pb from the molybdenite ore zone and its hornfels margin, Pb

  6. Chapter 13 Petrogenesis of the Campanian Ignimbrite: implications for crystal-melt separation and open-system processes from major and trace elements and Th isotopic data

    USGS Publications Warehouse

    Bohrson, W.A.; Spera, F.J.; Fowler, S.J.; Belkin, H.E.; de Vivo, B.; Rolandi, G.

    2006-01-01

    The Campanian Ignimbrite is a large-volume trachytic to phonolitic ignimbrite that was deposited at ???39.3 ka and represents one of a number of highly explosive volcanic events that have occurred in the region near Naples, Italy. Thermodynamic modeling using the MELTS algorithm reveals that major element variations are dominated by crystal-liquid separation at 0.15 GPa. Initial dissolved H2O content in the parental melt is ???3 wt.% and the magmatic system fugacity of oxygen was buffered along QFM+1. Significantly, MELTS results also indicate that the liquid line of descent is marked by a large change in the proportion of melt (from 0.46 to 0.09) at ???884??C, which leads to a discontinuity in melt composition (i.e., a compositional gap) and different thermodynamic and transport properties of melt and magma across the gap. Crystallization of alkali feldspar and plagioclase dominates the phase assemblage at this pseudo-invariant point temperature of ???884??C. Evaluation of the variations in the trace elements Zr, Nb, Th, U, Rb, Sm, and Sr using a mass balance equation that accounts for changing bulk mineral-melt partition coefficients as crystallization occurs indicates that crystal-liquid separation and open-system processes were important. Th isotope data yield an apparent isochron that is ???20 kyr younger than the age of the deposit, and age-corrected Th isotope data indicate that the magma body was an open system at the time of eruption. Because open-system behavior can profoundly change isotopic and elemental characteristics of a magma body, these Th results illustrate that it is critical to understand the contribution that open-system processes make to magmatic systems prior to assigning relevance to age or timescale information derived from such systems. Fluid-magma interaction has been proposed as a mechanism to change isotopic and elemental characteristics of magma bodies, but an evaluation of the mass and thermal constraints on such a process suggests

  7. Lead isotope compositions as guides to early gold mineralization: The North Amethyst vein system, Creede district, Colorado

    USGS Publications Warehouse

    Foley, Nora K.; Ayuso, Robert A.

    1994-01-01

    Pb isotope compositions from the late stage of the North Amethyst vein system and from the Bondholder and central and southern Creede mining districts are more radiogenic than the host volcanic rocks of the central cluster of the San Juan volcanic field. Our Pb isotope results indicate that early Au mineralization of the North Amethyst area may represent the product of an older and relatively local hydrothermal system distinct from that of the younger base metal and Ag mineralization found throughout the region. Fluids that deposited Au minerals may have derived their Pb isotope composition by a greater degree of interaction with shallow, relatively less radiogenic volcanic wall rocks. The younger, base metal and Ag-rich mineralization that overprints the Au mineralization in the North Amethyst area clearly has a more radiogenic isotopic signature, which implies that the later mineralization derived a greater component of its Pb from Proterozoic source rocks, or sediments derived from them.Paragenetically early sulfide-rich vein assemblages have the least radiogenic galenas and generally also have the highest Au contents. Thus, identification of paragenetically early vein assemblages with relatively unradiogenic Pb isotope compositions similar to those of the North Amethyst area provides an additional exploration tool for Au in the central San Juan Mountains area.

  8. Separating Autotrophic and Heterotrophic Contributions to Soil Respiration in Maize-Based Agroecosystems Using Stable Carbon Isotope Ratio Mass Spectrometry.

    NASA Astrophysics Data System (ADS)

    Amos, B.; Walters, D. T.; Madhavan, S.; Arkebauer, T. J.; Scoby, D. L.

    2005-12-01

    Any effort to establish a carbon budget for a growing crop by means of a thorough accounting of all C sources and sinks will require the ability to discriminate between autotrophic and heterotrophic contributions to soil surface CO2 flux. Autotrophic soil respiration (Ra) is defined as combined root respiration and the respiration of soil microorganisms residing in the rhizosphere and using root-derived carbohydrates as an energy source, while heterotrophic respiration (Rh) is defined as the respiration of soil microorganisms and macroorganisms not directly under the influence of the live root system and using SOM as an energy source. We partition soil surface CO2 flux into its autotrophic and heterotrophic components by combining root exclusion with stable carbon isotope techniques in production scale (~65 ha) maize-based agroecosystems. After flux measurements, small chambers are placed on collars in both root excluded shields and in non-root excluded soil, ambient headspace CO2 is removed using a soda lime trap, and soil-respired C is allowed to collect in the chambers. Soil respiration samples are then collected in 12mL evacuated exetainers and analyzed for δ13C by means of a Finnigan Delta-S isotope ratio mass spectrometer interfaced with a Thermo Finnigan GasBench II and a cryogenic trap to increase CO2 concentration. These δ13C measurements were made throughout the 2005 growing season in maize fields representing three agroecosystems: irrigated continuous maize, irrigated maize-soybean rotation, and rainfed maize soybean rotation. Estimates of autotrophic and heterotrophic soil respiration along with other results of this study will be presented.

  9. Selective IR multiphoton dissociation of molecules in a pulsed gas-dynamically cooled molecular flow interacting with a solid surface as an alternative to low-energy methods of molecular laser isotope separation

    SciTech Connect

    Makarov, G N; Petin, A N

    2016-03-31

    We report the results of studies on the isotope-selective infrared multiphoton dissociation (IR MFD) of SF{sub 6} and CF{sub 3}I molecules in a pulsed, gas-dynamically cooled molecular flow interacting with a solid surface. The productivity of this method in the conditions of a specific experiment (by the example of SF{sub 6} molecules) is evaluated. A number of low-energy methods of molecular laser isotope separation based on the use of infrared lasers for selective excitation of molecules are analysed and their productivity is estimated. The methods are compared with those of selective dissociation of molecules in the flow interacting with a surface. The advantages of this method compared to the low-energy methods of molecular laser isotope separation and the IR MPD method in the unperturbed jets and flows are shown. It is concluded that this method could be a promising alternative to the low-energy methods of molecular laser isotope separation. (laser separation of isotopes)

  10. Cosmic ray isotopes

    NASA Technical Reports Server (NTRS)

    Stone, E. C.

    1973-01-01

    The isotopic composition of cosmic rays is studied in order to develop the relationship between cosmic rays and stellar processes. Cross section and model calculations are reported on isotopes of H, He, Be, Al and Fe. Satellite instrument measuring techniques separate only the isotopes of the lighter elements.

  11. 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

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

    1995-05-30

    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.

  12. 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

    Horton, James A.; Hayden, Jr., Howard W.

    1995-01-01

    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.

  13. D/H ratios in speleothem fluid inclusions: A guide to variations in the isotopic composition of meteoric precipitation?

    USGS Publications Warehouse

    Harmon, R.S.; Schwarcz, H.P.; O'Neil, J.R.

    1979-01-01

    D/H ratios of fluid inclusion waters extracted from 230Th/234U-dated speleothems that were originally deposited under conditions of isotopic equilibrium should provide a direct estimate of the hydrogen isotopic composition of ancient meteoric waters. We present here D/H ratios for 47 fluid inclusion samples from thirteen speleothems deposited over the past 250,000 years at cave sites in Iowa, West Virginia, Kentucky and Missouri. At each site glacial-age waters are depleted in deuterium relative to those of interglacial age. The average interglacial/glacial shift in the hydrogen isotopic composition of meteoric precipitation over ice-free areas of east-central North America is estimated to be -12???. This shift is consistent with the present climatic models and can be explained in terms of the prevailing pattern of atmospheric circulation and an increased ocean-continent temperature gradient during glacial times which more than compensated for the increase in deuterium content of the world ocean. ?? 1979.

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

    SciTech Connect

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

    1991-09-01

    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.

  15. METHOD OF ISOTOPE CONCENTRATION

    DOEpatents

    Spevack, J.S.

    1957-04-01

    An isotope concentration process is described which consists of exchanging, at two or more different temperature stages, two isotopes of an element between substances that are physically separate from each other and each of which is capable of containing either of the isotopes, and withdrawing from a point between at least two of the temperatare stages one of the substances containing an increased concentration of the desired isotope.

  16. Alcohol fuel use: Implications for atmospheric levels of aldehydes, organic nitrates, pans, and peroxides: Separating sources using carbon isotopes

    SciTech Connect

    Gaffney, J.S.; Tanner, R.L.

    1988-01-01

    We have developed DiNitroPhenylHydrazone (DNPH) derivatization--high performance liquid chromatographic methods for measuring aldehydes in ambient samples with detection limits of approximately 1ppbV. These methods can be used for air or precipitation studies, and have been used for indoor measurements at much higher levels using shorter integration times. We are using gas chromatographs with electron capture detection (GCECD) to measure ambient levels of peroxyacyl nitrates and organic nitrates. Diffusion tubes with synthetically produced organic nitrates in n-tridecane solution are used to calibrate these systems. These compounds are important means of transporting NO/sub x/ over large scales due to their reduced tropospheric reactivity, low water solubilities, photolytic, and thermal stability. Their chemistries are coupled to aldehyde chemistry and are important greenhouse gases as well as phytotoxins. We have completed preliminary studies in Rio de Janeiro examining the atmospheric chemistry consequences of ethanol fuel usage. The urban air mass has been effected by the direct uncontrolled usage of ethanolgasoline and ethanoldiesel mixtures. We are exploring the use of luminol chemiluminescent detection of peroxides using gas chromatography to separate the various organic and inorganic peroxides. These compounds are coupled to the aldehyde chemistry, particularly in remote chemistries down-wind of urban sources. 13 refs.

  17. Momentum transport cross-section measurements for potassium and rubidium in rare gases and white light-induced separation of rubidium isotopes

    SciTech Connect

    Mugglin, D.T.

    1993-12-31

    This dissertation is concerned with two light-induced kinetic effects, light-induced diffusive pulling and light-induced drift. We use a light-induced diffusive pulling experiment to measure the ground state velocity-changing collision cross section (related to the momentum transport cross section and the diffusion coefficient) and the relative difference ({Delta}{sigma}/{sigma}) of the excited and ground state cross sections with respect to that of the ground state for potassium mixed with inert buffer gases. The measured excited state cross section is a weighted average of the potassium 4{sup 2}P{sub 1/2} and 4{sup 2}P{sub 3/2} fine structure levels, which are mixed by collisions with inert gas atoms. For the ground state cross sections, we obtain the following experimental results for potassium mixed with He, Ne, Ar, Kr, and Xe, respectively: 52 {+-} 4, 57 {+-} 8, 61 {+-} 5, 43 {+-} 5, and 60 {+-}5 {angstrom}{sup 2}. For {Delta}{sigma}/{sigma}, we obtain the following (in the same order): 0.085 {+-} 0.010, 0.058 {+-} 0.006, 0.41 {+-} 0.03, 0.43 {+-} 0.03, and 0.61 {+-} 0.05. For potassium-Ne and potassium-Ar, we combine these measurements with light-induced drift measurements of the ratio {Delta}{sigma}(J = 3/2) : {Delta}{sigma}(J = 1/2) to obtain absolute transport cross sections for the individual 4{sup 2}S{sub 1/2}, 4{sup 2}P{sub 1/2}, and 4{sup 2}P{sub 3/2} levels. We also use the light-induced diffusive pulling experimental method to measure {Delta}{sigma}/{sigma} for Rb-inert gas mixtures. We obtain values for the ground state diffusion cross section for Rb in several of the inert gases as well. We report the first experimental observation of the separation of two isotopes using broadband light by the process of white light-induced drift. For a light source, we use a broadband laser with an acousto-optic modulator as an output coupler. We verify the separation of the {sup 85}Rb and {sup 87}Rb isotopes.

  18. A ferrofluid guided system for the rapid separation of the non-magnetic particles in a microfluidic device.

    PubMed

    Asmatulu, R; Zhang, B; Nuraje, N

    2010-10-01

    A microfluidic device was fabricated via UV lithography technique to separate non-magnetic fluoresbrite carboxy microspheres (approximately 4.5 microm) in the pH 7 ferrofluids made of magnetite nanoparticles (approximately 10 nm). A mixture of microspheres and ferrofluid was injected to a lithographically developed Y shape microfluidic device, and then by applying the external magnet fields (0.45 T), the microspheres were clearly separated into different channels because of the magnetic force acting on those non-magnetic particles. During this study, various pumping speeds and particle concentrations associated with the various distances between the magnet and the microfluidic device were investigated for an efficient separation. This study may be useful for the separation of biological particles, which are very sensitive to pH value of the solutions.

  19. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    SciTech Connect

    van Soest, M.C.; Kennedy, B.M.; Evans, W.C.; Mariner, R.H.

    2002-04-30

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and CO{sub 2}/{sup 3}He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the contrary, all geochemical evidence suggests that there is a long-lived geothermal system in the Separation Creek area, which has not significantly changed since the early 1990s. There was no archived helium and carbon data, so a definite conclusion regarding the strong mantle signature observed in these tracers cannot yet be drawn. There is a distinct discrepancy between the yearly magma supply required to explain the current uplift (0.006 km{sup 3}/yr) and that required to explain the discharge of CO{sub 2} from the system (0.0005 km{sup 3}/yr). This discrepancy may imply that the chemical signal associated with the increase in magma supply has not reached the surface yet. With respect to this the small changes observed at upper Mesa Creek require further attention, due to the recent volcanic vent in that area it may be the location were the chemical signal related to the uplift can most quickly reach the surface. Occurrence of such strong mantle signals in cold/diffuse geothermal systems suggests that these systems should not be ignored during volcano monitoring or geothermal evaluation studies. Although the surface-expression of these springs in terms of heat is minimal, the chemistry carries important information concerning the size and nature of the underlying high-temperature system and any changes taking place in it.

  20. Single-tube, non-isotopic, multiplex PCR/OLA assay and sequence-coded separation for simultaneous screening of 31 cystic fibrosis mutations

    SciTech Connect

    Brinson, E.C.; Adriano, T.; Bloch, W.

    1994-09-01

    We have developed a rapid, single-tube, non-isotopic assay that screens a patient sample for the presence of 31 cystic fibrosis (CF) mutations. This assay can identify these mutations in a single reaction tube and a single electrophoresis run. Sample preparation is a simple, boil-and-go procedure, completed in less than an hour. The assay is composed of a 15-plex PCR, followed by a 61-plex oligonucleotide ligation assay (OLA), and incorporates a novel detection scheme, Sequence Coded Separation. Initially, the multiplex PCR amplifies 15 relevant segments of the CFTR gene, simultaneously. These PCR amplicons serve as templates for the multiplex OLA, which detects the normal or mutant allele at all loci, simultaneously. Each polymorphic site is interrogated by three oligonucleotide probes, a common probe and two allele-specific probes. Each common probe is tagged with a fluorescent dye, and the competing normal and mutant allelic probes incorporate different, non-nucleotide, mobility modifiers. These modifiers are composed of hexaethylene oxide (HEO) units, incorporated as HEO phosphoramidite monomers during automated DNA synthesis. The OLA is based on both probe hybridization and the ability of DNA ligase to discriminate single base mismatches at the junction between paired probes. Each single tube assay is electrophoresed in a single gel lane of a 4-color fluorescent DNA sequencer (Applied Biosystems, Model 373A). Each of the ligation products is identified by its unique combination of electrophoretic mobility and one of three colors. The fourth color is reserved for the in-lane size standard, used by GENESCAN{sup TM} software (Applied Biosystems) to size the OLA electrophoresis products. The Genotyper{sub TM} software (Applied Biosystems) decodes these Sequence-Coded-Separation data to create a patient summary report for all loci tested.

  1. Determination of Os by isotope dilution-inductively coupled plasma-mass spectrometry with the combination of laser ablation to introduce chemically separated geological samples

    NASA Astrophysics Data System (ADS)

    Sun, Yali; Ren, Minghao; Xia, Xiaoping; Li, Congying; Sun, Weidong

    2015-11-01

    A method was developed for the determination of trace Os in geological samples by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) with the combination of chemical separation and preconcentration. Samples are digested using aqua regia in Carius tubes, and the Os analyte is converted into volatile OsO4, which is distilled and absorbed with HBr. The HBr solution is concentrated for further Os purification using the microdistillation technique. The purified Os is dissolved in 10 μl of 0.02% sucrose-0.005% H3PO4 solution and then evaporated on pieces of perfluoroalkoxy (PFA) film, resulting in the formation of a tiny object (< 3 × 104 μm2 superficial area). Using LA-ICP-MS measurements, the object can give Os signals at least 100 times higher than those provided by routine solution-ICP-MS while successfully avoiding the memory effect. The procedural blank and detection limit in the developed technique are 3.0 pg and 1.8 pg for Os, respectively when 1 g of samples is taken. Reference materials (RM) are analyzed, and their Os concentrations obtained by isotope dilution are comparable to reference or literature values. Based on the individual RM results, the precision is estimated within the range of 0.6 to 9.4% relative standard deviation (RSD), revealing that this method is applicable to the determination of trace Os in geological samples.

  2. Development of an on-line flow injection Sr/matrix separation method for accurate, high-throughput determination of Sr isotope ratios by multiple collector-inductively coupled plasma-mass spectrometry.

    PubMed

    Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas

    2007-07-01

    This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.

  3. Generation of Radixenon Isotopes

    SciTech Connect

    McIntyre, Justin I.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Panisko, Mark E.; Pitts, W. K.; Pratt, Sharon L.; Reeder, Paul L.; Thomas, Charles W.

    2003-06-30

    Pacific Northwest National Laboratory has developed an automated system for separating Xe from air and can detect the following radioxenon isotopes, 131mXe, 133mXe, 133Xe, and 135Xe. This report details the techniques used to generate the various radioxenon isotopes that are used for the calibration of the detector as well as other isotopes that have the potential to interfere with the fission produced radioxenon isotopes. Fission production is covered first using highly enriched uranium followed by a description and results from an experiment to produce radioxenon isotopes from neutron activation of ambient xenon.

  4. ISOTOPE CONVERSION DEVICE

    DOEpatents

    Wigner, E.P.; Young, G.J.; Ohlinger, L.A.

    1957-12-01

    This patent relates to nuclear reactors of tbe type utilizing a liquid fuel and designed to convert a non-thermally fissionable isotope to a thermally fissionable isotope by neutron absorption. A tank containing a reactive composition of a thermally fissionable isotope dispersed in a liquid moderator is disposed within an outer tank containing a slurry of a non-thermally fissionable isotope convertible to a thermally fissionable isotope by neutron absorption. A control rod is used to control the chain reaction in the reactive composition and means are provided for circulating and cooling the reactive composition and slurry in separate circuits.

  5. Guiding Empirical and Theoretical Explorations of Organic Matter Decay By Synthesizing Temperature Responses of Enzyme Kinetics, Microbes, and Isotope Fluxes

    NASA Astrophysics Data System (ADS)

    Billings, S. A.; Ballantyne, F.; Lehmeier, C.; Min, K.

    2014-12-01

    Soil organic matter (SOM) transformation rates generally increase with temperature, but whether this is realized depends on soil-specific features. To develop predictive models applicable to all soils, we must understand two key, ubiquitous features of SOM transformation: the temperature sensitivity of myriad enzyme-substrate combinations and temperature responses of microbial physiology and metabolism, in isolation from soil-specific conditions. Predicting temperature responses of production of CO2 vs. biomass is also difficult due to soil-specific features: we cannot know the identity of active microbes nor the substrates they employ. We highlight how recent empirical advances describing SOM decay can help develop theoretical tools relevant across diverse spatial and temporal scales. At a molecular level, temperature effects on purified enzyme kinetics reveal distinct temperature sensitivities of decay of diverse SOM substrates. Such data help quantify the influence of microbial adaptations and edaphic conditions on decay, have permitted computation of the relative availability of carbon (C) and nitrogen (N) liberated upon decay, and can be used with recent theoretical advances to predict changes in mass specific respiration rates as microbes maintain biomass C:N with changing temperature. Enhancing system complexity, we can subject microbes to temperature changes while controlling growth rate and without altering substrate availability or identity of the active population, permitting calculation of variables typically inferred in soils: microbial C use efficiency (CUE) and isotopic discrimination during C transformations. Quantified declines in CUE with rising temperature are critical for constraining model CUE estimates, and known changes in δ13C of respired CO2 with temperature is useful for interpreting δ13C-CO2 at diverse scales. We suggest empirical studies important for advancing knowledge of how microbes respond to temperature, and ideas for theoretical

  6. Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Oak Ridge Gaseous Diffusion Plant Site

    SciTech Connect

    Not Available

    1991-09-01

    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. 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. A programmatic document for use in screening DOE sites to locate the U-AVLIS production plant was developed and implemented in two parts (Wolsko et al. 1991). 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 then 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 ORGDP 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. 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. Following the site description and additional data requirements, Sec. 4 provides a short, qualitative assessment of potential environmental issues. 37 refs., 20 figs., 18 tabs.

  7. Strong anion exchange liquid chromatographic separation of protein amino acids for natural 13C-abundance determination by isotope ratio mass spectrometry.

    PubMed

    Abaye, Daniel A; Morrison, Douglas J; Preston, Tom

    2011-02-15

    Amino acids are the building blocks of proteins and the analysis of their (13)C abundances is greatly simplified by the use of liquid chromatography (LC) systems coupled with isotope ratio mass spectrometry (IRMS) compared with gas chromatography (GC)-based methods. To date, various cation exchange chromatography columns have been employed for amino acid separation. Here, we report strong anion exchange chromatography (SAX) coupled to IRMS with a Liquiface interface for amino acid δ(13)C determination. Mixtures of underivatised amino acids (0.1-0.5 mM) and hydrolysates of representative proteins (prawns and bovine serum albumin) were resolved by LC/IRMS using a SAX column and inorganic eluents. Background inorganic carbon content was minimised through careful preparation of alkaline reagents and use of a pre-injector on-line carbonate removal device. SAX chromatography completely resolved 11 of the 16 expected protein amino acids following acid hydrolysis in underivatised form. Basic and neutral amino acids were resolved with 35 mM NaOH in isocratic mode. Elution of the aromatic and acidic amino acids required a higher hydroxide concentration (180 mM) and a counterion (NO 3-, 5-25 mM). The total run time was 70 min. The average δ(13)C precision of baseline-resolved peaks was 0.75‰ (range 0.04 to 1.06‰). SAX is a viable alternative to cation chromatography, especially where analysis of basic amino acids is important. The technology shows promise for (13)C amino acid analysis in ecology, archaeology, forensic science, nutrition and protein metabolism.

  8. Onflow liquid chromatography at critical conditions coupled to (1)H and (2)H nuclear magnetic resonance as powerful tools for the separation of poly(methylmethacrylate) according to isotopic composition.

    PubMed

    Hehn, Mathias; Sinha, Pritish; Pasch, Harald; Hiller, Wolf

    2015-03-27

    The present work addresses a major challenge in polymer chromatography by developing a method to separate and analyze polymers with identical molar masses, chemical structures and tacticities that is solely based on differences in isotope composition. For the first time, liquid chromatography at critical conditions (LCCC) was used to separate PMMA regarding the H and D isotopes. At critical conditions of H-PMMA, D-PMMA eluted in the adsorption mode and vice versa. By online onflow LCCC-NMR, both PMMA species were clearly identified. Different from other detectors, NMR can distinguish between H and D. Onflow LCCC-H/NMR and LCCC-D/NMR measurements were carried out and the H/D-blend components were detected. (1)H and (13)C NMR provided the tacticity of protonated PMMA. Double resonance (13)C{H} and triple resonance (13)C{H,D} provided the tacticity of the deuterated samples. Samples with similar tacticities were used to ensure that separation occurs solely regarding the isotope labeling.

  9. Separation of flavonoids from Millettia griffithii with high-performance counter-current chromatography guided by anti-inflammatory activity.

    PubMed

    Tang, Huan; Wu, Bo; Chen, Kai; Pei, Heying; Wu, Wenshuang; Ma, Liang; Peng, Aihua; Ye, Haoyu; Chen, Lijuan

    2015-02-01

    Millettia griffithii is a unique Chinese plant located in the southern part of Yunnan Province. Up to now, there is no report about its phytochemical or related bioactivity research. In our previous study, the n-hexane crude extract of Millettia griffithii revealed significant anti-inflammatory activity at 100 μg/mL, inspiring us to explore the anti-inflammatory constituents. Four fractions (I, II, III, and A) were fractionated from n-hexane crude extract by high-performance counter-current chromatography with solvent system composed of n-hexane/ethyl acetate/methanol/water (8:9:8:9, v/v) and then were investigated for the potent anti-inflammatory activity. Fraction A, with the most potent inhibitory activity was further separated to give another four fractions (IV, V, VI, and B) with solvent system composed of n-hexane/ethyl acetate/methanol/water (8:4:8:4, v/v). Compound V and fraction B exhibited remarkable anti-inflammatory activity with nitric oxide inhibitory rate of 80 and 65%, which was worth further fractionation. Then, three fractions (VII, VIII, and IX) were separated from fraction B with a solvent system composed of n-hexane/ethyl acetate/methanol/water (8:1:8:1, v/v), with compound VIII demonstrating the most potent inhibitory activity (80%). Finally, the IC50 values of compound V and VIII were tested as 38.2 and 14.9 μM. The structures were identified by electrospray ionization mass spectrometry and(1)H and (13)C NMR spectroscopy.

  10. Bioassay-guided preparative separation of angiotensin-converting enzyme inhibitory C-flavone glycosides from Desmodium styracifolium by recycling complexation high-speed counter-current chromatography.

    PubMed

    Zhang, Ying-Qi; Luo, Jian-Guang; Han, Chao; Xu, Jin-Fang; Kong, Ling-Yi

    2015-01-01

    A new strategy of the convergence of high-speed counter-current chromatography (HSCCC) and bioactive assay technique was developed for rapidly screening and separating the angiotensin-converting enzyme (ACE) inhibitors from the aerial parts of Desmodium styracifolium. Bioactivity-guided fractionation of the crude extract was first established to target the bioactive fractions based on HSCCC coupled with in vitro ACE inhibitory assay. Subsequently, the bioactive fractions were further separated by the recycling complexation HSCCC respectively, using 0.10 mol/L copper sulfate in the lower phase of two-phase solvent system composed of n-butanol/water (1:1, v/v). Five C-glycosylflavones, vicenin 2 (1), carlinoside (2), vicenin 1 (3), schaftoside (4) and vicenin 3 (5), were successfully obtained. Their chemical structures were identified using ESI-MS and NMR. All the isolates showed in vitro ACE inhibitory activity with the IC50 values between 33.62 and 58.37 μM. The results demonstrated that the established method was proposed as an excellent strategy to systematically screen and purify active compounds from traditional Chinese medicines.

  11. At-line hyphenation of high-speed countercurrent chromatography with Sephadex LH-20 column chromatography for bioassay-guided separation of antioxidants from vine tea (Ampelopsis grossedentata).

    PubMed

    Ma, Ruyi; Zhou, Rongrong; Tong, Runna; Shi, Shuyun; Chen, Xiaoqing

    2017-01-01

    Vine tea (Ampelopsis grossedentata), a widely used healthy tea, beverage and herbal medicine, exhibited strong antioxidant activity. However, systematic purification of antioxidants, especially for those with similar structures or polarities, is a challenging work. Here, we present a novel at-line hyphenation of high-speed countercurrent chromatography with Sephadex LH-20 column chromatography (HSCCC-Sephadex LH-20 CC) for rapid and efficient separation of antioxidants from vine tea target-guided by 1,1-diphenyl-2-picryl-hydrazyl radical-high performance liquid chromatography (DPPH-HPLC) experiment. A makeup pump, a six-port switching valve and a trapping column were served as interface. The configuration had no operational time and mobile phase limitations between two dimensional chromatography and showed great flexibility without tedious sample-handling procedure. Seven targeted antioxidants were firstly separated by stepwise HSCCC using petroleum ether-ethyl acetate-methanol-water (4:9:4:9, v/v/v/v) and (4:9:5:8, v/v/v/v) as solvent systems, and then co-eluted antioxidants were on-line trapped, concentrated and desorbed to Sephadex LH-20 column for further off-line purification by methanol. It is noted that six elucidated antioxidants with purity over 95% exhibited stronger activity than ascorbic acid (VC). More importantly, this at-line hyphenated strategy could sever as a rapid and efficient pathway for systematic purification of bioactive components from complex matrix.

  12. New insight from noble gas and stable isotopes of geothermal/hydrothermal fluids at Caviahue-Copahue Volcanic Complex: Boiling steam separation and water-rock interaction at shallow depth

    NASA Astrophysics Data System (ADS)

    Roulleau, Emilie; Tardani, Daniele; Sano, Yuji; Takahata, Naoto; Vinet, Nicolas; Bravo, Francisco; Muñoz, Carlos; Sanchez, Juan

    2016-12-01

    We measured noble gas and stable isotopes of the geothermal and hydrothermal fluids of the Caviahue-Copahue Volcanic Complex (CCVC), one of the most important geothermal systems in Argentina/Chile, in order to provide new insights into fluid circulation and origin. With the exception of Anfiteatro and Chancho-co geothermal systems, mantle-derived helium dominates in the CCVC fluids, with measured 3He/4He ratios up to 7.86Ra in 2015. Their positive δ15N is an evidence for subducted sediment-derived nitrogen, which is commonly observed in subduction settings. Both He-N2-Ar composition and positive correlation between δD-H2O and δ18O-H2O suggest that the fluids from Anfiteatro and Chancho-co (and partly from Pucon-Mahuida as well, on the southern flank of Copahue volcano) represent a meteoric water composition with a minor magmatic contribution. The Ne, Kr and Xe isotopic compositions are entirely of atmospheric origin, but processes of boiling and steam separation have led to fractionation of their elemental abundances. We modeled the CCVC fluid evolution using Rayleigh distillation curves, considering an initial air saturated geothermal water (ASGW) end-member at 250 and 300 °C, followed by boiling and steam separation at lower temperatures (from 200 °C to 150 °C). Between 2014 and 2015, the CCVC hydrogen and oxygen isotopes shifted from local meteoric water-dominated to andesitic water-dominated signature. This shift is associated with an increase of δ13C values and Stotal, HCl and He contents. These characteristics are consistent with a change in the gas ascent pathway between 2014 and 2015, which in turn induced higher magmatic-hydrothermal contribution in the fluid signature. The composition of the magmatic source of the CCVC fluids is: 3He/4He = 7.7Ra, δ15N = + 6‰, and δ13C = - 6.5‰. Mixing models between air-corrected He and N suggest the involvement of 0.5% to 5% of subducted sediments in the magmatic source. The magmatic sulfur isotopic

  13. Apparatus for extraction and separation of a preferentially photo-dissociated molecular isotope into positive and negative ions by means of an electric field

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E. (Inventor)

    1978-01-01

    Molecules of one and the same isotope were preferentially photodissociated by a laser and an ultraviolet source, or by multiphoton absorption of laser radiation. The resultant ions were confined with a magnetic field, moved in opposite directions by an electric field, extracted from the photodissociation region by means of screening and accelerating grids, and collected in ducts.

  14. Oxygen isotope composition of water and snow-ice cover of isolated lakes at various stages of separation from the White Sea

    NASA Astrophysics Data System (ADS)

    Lisitzin, A. P.; Vasil'chuk, Yu. K.; Shevchenko, V. P.; Budantseva, N. A.; Krasnova, E. D.; Pantyulin, A. N.; Filippov, A. S.; Chizhova, Ju. N.

    2013-04-01

    This study aimed to analyze the oxygen isotope composition of water, ice, and snow in water bodies isolated from the White Sea and to identify the structural peculiarities of these pools during the winter period. The studies were performed during early spring in Kandalaksha Bay of the White Sea, in Velikaya Salma Strait and in Rugoserskaya Inlet. The studied water bodies differ in their degree of isolation from the sea. In particular, Ermolinskaya Inlet has normal water exchange with the sea; the Lake on Zelenyi Cape represents the first stage of isolation; i. e., it has permanent water exchange with the sea by the tide. Kislo-Sladkoe Lake receives sea water from time to time. Trekhtsvetnoe Lake is totally isolated from the sea and is a typical meromictic lake. Finally, Nizhnee Ershovskoe Lake exhibits some features of a saline water body. The oxygen isotope profile of the water column in Trekhtsvetnoe Lake allows defining three layers; this lake may be called typically meromictic. The oxygen isotope profile of the water column in Kislo-Sladkoe Lake is even from the surface to the bottom. The variability of δ18O is minor in Lake on Zelenyi Cape. A surface layer (0-1 m) exists in Nizhnee Ershovskoe Lake, and the oxygen isotope variability is well pronounced. Deeper, where the freshwater dominates, the values of ?18Îvary insignificantly disregarding the water depth and temperature. This fresh water lake is not affected by the seawater and is not stratified according to the isotope profile. It is found that applying the values of ?18Î and profiles of temperature and salinity may appear as an effective method in defining the water sources feeding the water bodies isolated from the sea environment.

  15. Method for laser induced isotope enrichment

    DOEpatents

    Pronko, Peter P.; Vanrompay, Paul A.; Zhang, Zhiyu

    2004-09-07

    Methods for separating isotopes or chemical species of an element and causing enrichment of a desired isotope or chemical species of an element utilizing laser ablation plasmas to modify or fabricate a material containing such isotopes or chemical species are provided. This invention may be used for a wide variety of materials which contain elements having different isotopes or chemical species.

  16. Carbon isotopes of plant biomarkers record past changes in the carbon cycle, but separating signal from noise is key to reducing uncertainties

    NASA Astrophysics Data System (ADS)

    Diefendorf, A. F.; Freeman, K. H.; Wing, S. L.; Currano, E. D.

    2014-12-01

    The carbon isotopic composition of plant biomarkers (δ13C) can provide unique insights into the past carbon cycle perturbations and associated climate change, however local records are influenced by ecological processes, local climate, as well as changes in the carbon isotope composition of the atmosphere. To examine the sources and amounts of geographic variation, we focused on long-term changes in the carbon cycle. We combined modern calibrations, δ13C of biomarkers in sediment, and Monte Carlo analyses to measure and predict the fractionation of carbon isotopes by plants (Δleaf) and to estimate error. We used data from multiple sites of different ages, in the western U.S. For each age and location, Δleaf was calculated from the δ13C of plant biomarkers and atmospheric δ13C values inferred from marine carbonates. Δleaf values calculated from n-alkanes and triterpenoids (angiosperm biomarkers) were found to be the same at each site. Δleaf calculated from diterpenoids (conifer biomarkers) was 2‰ lower. This is consistent with differences in Δleaf between living angiosperms and conifers. Predicted Δleaf values, from modern calibrations and paleoclimate data, were consistently offset (0.7‰) from measured values indicating that modern calibrations are useful for reconciling past changes in plant fractionation and that vegetation and precipitation, like modern plants, were the key controls on Δleaf in ancient vegetation. However, uncertainties in the measured and predicted Δleaf values were very large (>2‰, 1σ). A one-at-a-time sensitivity analysis indicates that 'biological noise' in modern calibrations explains most of this uncertainty. If the full extent of this biological noise were transferred to sediments, then extracting signal from noise would be challenging. However, we speculate that the process of deposition homogenizes variability at the leaf and tree level thereby reducing 'biological noise' observed in modern calibrations.

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

    SciTech Connect

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

    1991-09-01

    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.

  18. Science: Grade 3. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  19. Science: Grade 7. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  20. Science: Grade 8. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  1. Science: Grade 5. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  2. Science: Grade 6. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  3. Science: Grade 9. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  4. Science: Grade 2. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  5. Science: Grade 1. Interim Guide.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education and Training, Winnipeg.

    This guide is one of a set of 10 science guides, each covering a separate grade in Manitoba, together covering kindergarten through grade 9. The guides have been designed to provide a framework for building scientific concepts and developing the learning of process skills. They replace an earlier set of guides dated 1979. Each guide is essentially…

  6. Meteoritic Sulfur Isotopic Analysis

    NASA Technical Reports Server (NTRS)

    Thiemens, Mark H.

    1996-01-01

    Funds were requested to continue our program in meteoritic sulfur isotopic analysis. We have recently detected a potential nucleosynthetic sulfur isotopic anomaly. We will search for potential carriers. The documentation of bulk systematics and the possible relation to nebular chemistry and oxygen isotopes will be explored. Analytical techniques for delta(sup 33), delta(sup 34)S, delta(sup 36)S isotopic analysis were improved. Analysis of sub milligram samples is now possible. A possible relation between sulfur isotopes and oxygen was detected, with similar group systematics noted, particularly in the case of aubrites, ureilites and entstatite chondrites. A possible nucleosynthetic excess S-33 has been noted in bulk ureilites and an oldhamite separate from Norton County. High energy proton (approximately 1 GeV) bombardments of iron foils were done to experimentally determine S-33, S-36 spallogenic yields for quantitation of isotopic measurements in iron meteorites. Techniques for measurement of mineral separates were perfected and an analysis program initiated. The systematic behavior of bulk sulfur isotopes will continue to be explored.

  7. Isotopic Biogeochemistry

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  8. Refined separation of combined Fe–Hf from rock matrices for isotope analyses using AG-MP-1M and Ln-Spec chromatographic extraction resins

    PubMed Central

    Cheng, Ting; Nebel, Oliver; Sossi, Paolo A.; Chen, Fukun

    2014-01-01

    A combined procedure for separating Fe and Hf from a single rock digestion is presented. In a two-stage chromatographic extraction process, a purified Fe fraction is first quantitatively separated from the rock matrix using AG-MP-1M resin in HCl. Hafnium is subsequently isolated using a modified version of a commonly applied method using Eichrom LN-Spec resin. Our combined method includes:•Purification of Fe from the rock matrix using HCl, ready for mass spectrometric analysis.•Direct loading of the matrix onto the resin that is used for Hf purification.•Collection of a Fe-free Hf fraction. PMID:26150946

  9. Unusual isotopic composition of C-CO2 from sterilized soil microcosms: a new way to separate intracellular from extracellular respiratory metabolisms.

    NASA Astrophysics Data System (ADS)

    Kéraval, Benoit; Alvarez, Gaël; Lehours, Anne Catherine; Amblard, Christian; Fontaine, Sebastien

    2015-04-01

    intact cells were observed by microscopy. These "ghost" cells were completely destroyed by the irradiation-autoclaving combination releasing large amount of soluble C. The soil respiration (O2 consumption and CO2 production) was reduced by irradiation and autoclaving but not stopped, suggesting the presence of an EXOMET. The delta 13C of CO2 released in the irradiated-autoclaved soil was strongly depleted (-70‰) indicating that this extracellular metabolism induced a substantial isotopic fractionation. Our findings suggest that two main oxidative metabolisms co-occur in soils: cell respiration and EXOMET. The isotopic fractionation induced by the EXOMET open perspectives for its quantification in non-sterilized living soils.

  10. Biomagnification profiles of polycyclic aromatic hydrocarbons, alkylphenols and polychlorinated biphenyls in Tokyo Bay elucidated by delta13C and delta15N isotope ratios as guides to trophic web structure.

    PubMed

    Takeuchi, Ichiro; Miyoshi, Noriko; Mizukawa, Kaoruko; Takada, Hideshige; Ikemoto, Tokutaka; Omori, Koji; Tsuchiya, Kotaro

    2009-05-01

    Biomagnification profiles of polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and polychlorinated biphenyls (PCBs) from the innermost part of Tokyo Bay, Japan were analyzed using stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope ratios as guides to trophic web structure. delta(15)N analysis indicated that all species of mollusks tested were primary consumers, while decapods and fish were secondary consumers. Higher concentrations of PCBs occurred in decapods and fish than in mollusks. In contrast, concentrations of PAHs and alkylphenols were lower in decapods and fish than in mollusks. Unlike PCBs, whose concentrations largely increased with increasing delta(15)N (i.e. increasing trophic level), all PAHs and alkylphenols analyzed followed a reverse trend. Molecular weights of PAHs are lower than those of PCBs, therefore low membrane permeability caused by large molecular size is an unlikely factor in the "biodilution" of PAHs. Organisms at higher trophic levels may rapidly metabolize PAHs or they may assimilate less of them.

  11. Dry phase reactor for generating medical isotopes

    DOEpatents

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  12. Separation and measurement of Pa, Th, and U isotopes in marine sediments by microwave-assisted digestion and multiple collector inductively coupled plasma mass spectrometry.

    PubMed

    Negre, César; Thomas, Alexander L; Mas, José Luis; Garcia-Orellana, Jordi; Henderson, Gideon M; Masqué, Pere; Zahn, Rainer

    2009-03-01

    This manuscript describes a new protocol for determination of Pa/Th/U in marine sediments. It is based on microwave-assisted digestion and represents an important reduction of working time over conventional hot-plate digestion methods, and the use of HClO(4) is avoided. Although Th and U are completely dissolved with a first microwave step, around 40% of (231)Pa remains undissolved, and a short hot-plate step with reverse aqua regia is required to achieve total digestion and spike equilibration. Next, the method involves a separation of these elements and a further purification of the Pa fraction using Dowex AG1-X8 resin. Separation with Bio-Rad and Sigma-Aldrich resins was compared; although both perform similarly for Th and U, Pa yields are higher with Bio-Rad. Finally, samples are measured using a Nu instruments multiple collector inductively coupled plasma mass spectrometer (MC-ICPMS). Overall chemical yields range around 50% for Pa, 60% for Th, and 70% for U.

  13. Separation and quantification of silver nanoparticles and silver ions using reversed phase high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry in combination with isotope dilution analysis.

    PubMed

    Sötebier, Carina A; Weidner, Steffen M; Jakubowski, Norbert; Panne, Ulrich; Bettmer, Jörg

    2016-10-14

    A reversed phase high performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer (HPLC-ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution.

  14. Electrochemically controlled iron isotope fractionation

    NASA Astrophysics Data System (ADS)

    Black, Jay R.; Young, Edward D.; Kavner, Abby

    2010-02-01

    Variations in the stable isotope abundances of transition metals have been observed in the geologic record and trying to understand and reconstruct the physical/environmental conditions that produced these signatures is an area of active research. It is clear that changes in oxidation state lead to large fractionations of the stable isotopes of many transition metals such as iron, suggesting that transition metal stable isotope signatures could be used as a paleo-redox proxy. However, the factors contributing to these observed stable isotope variations are poorly understood. Here we investigate how the kinetics of iron redox electrochemistry generates isotope fractionation. Through a combination of electrodeposition experiments and modeling of electrochemical processes including mass-transport, we show that electron transfer reactions are the cause of a large isotope separation, while mass transport-limited supply of reactant to the electrode attenuates the observed isotopic fractionation. Furthermore, the stable isotope composition of electroplated transition metals can be tuned in the laboratory by controlling parameters such as solution chemistry, reaction overpotential, and solution convection. These methods are potentially useful for generating isotopically-marked metal surfaces for tracking and forensic purposes. In addition, our studies will help interpret stable isotope data in terms of identifying underlying electron transfer processes in laboratory and natural samples.

  15. Adaptive optics and laser guide stars at Lick observatory

    SciTech Connect

    Brase, J.M.

    1994-11-15

    For the past several years LLNL has been developing adaptive optics systems for correction of both atmospheric turbulence effects and thermal distortions in optics for high-power lasers. Our early work focused on adaptive optics for beam control in laser isotope separation and ground-based free electron lasers. We are currently developing innovative adaptive optics and laser systems for sodium laser guide star applications at the University of California`s Lick and Keck Observeratories. This talk will describe our adaptive optics technology and some of its applications in high-resolution imaging and beam control.

  16. CCR7 guides migration of mesenchymal stem cell to secondary lymphoid organs: a novel approach to separate GvHD from GvL effect.

    PubMed

    Li, Hong; Jiang, YanMing; Jiang, XiaoXia; Guo, XiMin; Ning, HongMei; Li, YuHang; Liao, Li; Yao, HuiYu; Wang, XiaoYan; Liu, YuanLin; Zhang, Yi; Chen, Hu; Mao, Ning

    2014-07-01

    Inefficient homing of systemically infused mesenchymal stem cells (MSCs) limits the efficacy of existing MSC-based clinical graft-versus-host disease (GvHD) therapies. Secondary lymphoid organs (SLOs) are the major niches for generating immune responses or tolerance. MSCs home to a wide range of organs, but rarely to SLOs after intravenous infusion. Thus, we hypothesized that targeted migration of MSCs into SLOs may significantly improve their immunomodulatory effect. Here, chemokine receptor 7 (CCR7) gene, encoding a receptor that specifically guides migration of immune cells into SLOs, was engineered into a murine MSC line C3H10T1/2 by retrovirus transfection system (MSCs/CCR7). We found that infusion of MSCs/CCR7 potently prolonged the survival of GvHD mouse model. The infused MSCs/CCR7 migrate to SLOs, relocate in proximity with T lymphocytes, therefore, potently inhibited their proliferation, activation, and cytotoxicity. Natural killer (NK) cells contribute to the early control of leukemia relapse. Although MSCs/CCR7 inhibited NK cell activity in vitro coculture, they did not impact on the proportion and cytotoxic capacities of NK cells in the peripheral blood of GvHD mice. In an EL4 leukemia cell loaded GvHD model, MSCs/CCR7 infusion preserved the graft-versus-leukemia (GvL) effect. In conclusion, this study demonstrates that CCR7 guides migration of MSCs to SLOs and thus highly intensify their in vivo immunomodulatory effect while preserving the GvL activity. This exciting therapeutic strategy may improve the clinical efficacy of MSC based therapy for immune diseases.

  17. GEOMETRY, TENTATIVE GUIDES.

    ERIC Educational Resources Information Center

    KLIER, KATHERINE M.

    PRESENTED IS A FUSED COURSE IN PLANE, SOLID, AND COORDINATE GEOMETRY. ELEMENTARY SET THEORY, LOGIC, AND THE PRINCIPLE OF SEPARATION PROVIDE UNIFYING THREADS THROUGHOUT THE TEXT. THE TWO CURRICULUM GUIDES HAVE BEEN PREPARED FOR USE WITH TWO DIFFERENT TEXTS. EITHER CURRICULUM GUIDE MAY BE USED DEPENDING UPON THE CHOICE OF THE TEACHER AND THE NEEDS…

  18. Research Directed at Developing a Classical Theory to Describe Isotope Separation of Polyatomic Molecules Illuminated by Intense Infrared Radiation. Final Report for period May 7, 1979 to September 30, 1979; Extension December 31, 1997

    DOE R&D Accomplishments Database

    Lamb, W. E. Jr.

    1981-12-01

    This final report describes research on the theory of isotope separation produced by the illumination of polyatomic molecules by intense infrared laser radiation. This process is investigated by treating the molecule, sulfur hexafluoride, as a system of seven classical particles that obey the Newtonian equations of motion. A minicomputer is used to integrate these differential equations. The particles are acted on by interatomic forces, and by the time-dependent electric field of the laser. We have a very satisfactory expression for the interaction of the laser and the molecule which is compatible with infrared absorption and spectroscopic data. The interatomic potential is capable of improvement, and progress on this problem is still being made. We have made several computer runs of the dynamical behavior of the molecule using a reasonably good model for the interatomic force law. For the laser parameters chosen, we find that typically the molecule passes quickly through the resonance region into the quasi-continuum and even well into the real continuum before dissociation actually occurs. When viewed on a display terminal, the motions are exceedingly complex. As an aid to the visualization of the process, we have made a number of 16 mm movies depicting a three-dimensional representation of the motion of the seven particles. These show even more clearly the enormous complexity of the motions, and make clear the desirability of finding ways of characterizing the motion in simple ways without giving all of the numerical detail. One of the ways to do this is to introduce statistical parameters such as a temperature associated with the distribution of kinetic energies of the single particle. We have made such an analysis of our data runs, and have found favorable indications that such methods will prove useful in keeping track of the dynamical histories.

  19. Method and apparatus for separation of heavy and tritiated water

    DOEpatents

    Lee, Myung W.

    2001-01-01

    The present invention is a bi-thermal membrane process for separating and recovering hydrogen isotopes from a fluid containing hydrogen isotopes, such as water and hydrogen gas. The process in accordance with the present invention provides counter-current cold and hot streams of the fluid separated with a thermally insulating and chemically transparent proton exchange membrane (PEM). The two streams exchange hydrogen isotopes through the membrane: the heavier isotopes migrate into the cold stream, while the lighter isotopes migrate into the hot stream. The heavy and light isotopes are continuously withdrawn from the cold and hot streams respectively.

  20. Transuranium isotopes

    SciTech Connect

    Hoffman, D.C.

    1985-12-01

    The needs of the research community for the production of transuranium isotopes, the quantities required, the continuity of production desired, and what a new steady state neutron source would have to provide to satisfy these needs are discussed. Examples of past frontier research which need these isotopes as well as an outline of the proposed Large Einsteinium Activation Program, LEAP, which requires roughly ten times the current production of /sup 254/Es are given. 15 refs., 5 figs., 4 tabs.

  1. Isotopic chirality

    SciTech Connect

    Floss, H.G.

    1994-12-01

    This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

  2. Effects of (18)O isotopic substitution on the rotational spectra and potential splitting in the OH-OH2 complex: improved measurements for (16)OH-(16)OH2 and (18)OH-(18)OH2, new measurements for the mixed isotopic forms, and ab initio calculations of the (2)A'-(2)A" energy separation.

    PubMed

    Brauer, Carolyn S; Sedo, Galen; Dahlke, Erin; Wu, Shenghai; Grumstrup, Erik M; Leopold, Kenneth R; Marshall, Mark D; Leung, Helen O; Truhlar, Donald G

    2008-09-14

    Rotational spectra have been observed for (16)OH-(16)OH(2), (16)OH-(18)OH(2), (18)OH-(16)OH(2), and (18)OH-(18)OH(2) with complete resolution of the nuclear magnetic hyperfine structure from the OH and water protons. Transition frequencies have been analyzed for each isotopic form using the model of Marshall and Lester [J. Chem. Phys. 121, 3019 (2004)], which accounts for partial quenching of the OH orbital angular momentum and the decoupling of the electronic spin from the OH molecular axis. The analysis accounts for both the ground ((2)A(')) and first electronically excited ((2)A(")) states of the system, which correspond roughly to occupancy by the odd electron in the p(y) and p(x) orbitals, respectively (where p(y) is in the mirror plane of the complex and p(x) is perpendicular to p(y) and the OH bond axis). The spectroscopic measurements yield a parameter, rho, which is equal to the vibrationally averaged (2)A(')-(2)A(") energy separation that would be obtained if spin-orbit coupling and rotation were absent. For the parent species, rho = -146.560 27(9) cm(-1). (18)O substitution on the water increases /rho/ by 0.105 29(10) cm(-1), while substitution on the OH decreases /rho/ by 0.068 64(11) cm(-1). In the OH-OH(2) complex, the observed value of rho implies an energy spacing between the rotationless levels of the (2)A(') and (2)A(") states of 203.76 cm(-1). Ab initio calculations have been performed with quadratic configuration interaction with single and double excitations (QCISD), as well as multireference configuration interaction (MRCI), both with and without the inclusion of spin-orbit coupling. The MRCI calculations with spin-orbit coupling perform the best, giving a value of 171 cm(-1) for the (2)A(')-(2)A(") energy spacing at the equilibrium geometry. Calculations along the large-amplitude bending coordinates of the OH and OH(2) moieties within the complex are presented and are shown to be consistent with a vibrational averaging effect as the main

  3. Multiple linear regression for isotopic measurements

    NASA Astrophysics Data System (ADS)

    Garcia Alonso, J. I.

    2012-04-01

    There are two typical applications of isotopic measurements: the detection of natural variations in isotopic systems and the detection man-made variations using enriched isotopes as indicators. For both type of measurements accurate and precise isotope ratio measurements are required. For the so-called non-traditional stable isotopes, multicollector ICP-MS instruments are usually applied. In many cases, chemical separation procedures are required before accurate isotope measurements can be performed. The off-line separation of Rb and Sr or Nd and Sm is the classical procedure employed to eliminate isobaric interferences before multicollector ICP-MS measurement of Sr and Nd isotope ratios. Also, this procedure allows matrix separation for precise and accurate Sr and Nd isotope ratios to be obtained. In our laboratory we have evaluated the separation of Rb-Sr and Nd-Sm isobars by liquid chromatography and on-line multicollector ICP-MS detection. The combination of this chromatographic procedure with multiple linear regression of the raw chromatographic data resulted in Sr and Nd isotope ratios with precisions and accuracies typical of off-line sample preparation procedures. On the other hand, methods for the labelling of individual organisms (such as a given plant, fish or animal) are required for population studies. We have developed a dual isotope labelling procedure which can be unique for a given individual, can be inherited in living organisms and it is stable. The detection of the isotopic signature is based also on multiple linear regression. The labelling of fish and its detection in otoliths by Laser Ablation ICP-MS will be discussed using trout and salmon as examples. As a conclusion, isotope measurement procedures based on multiple linear regression can be a viable alternative in multicollector ICP-MS measurements.

  4. Antioxidant activity guided separation of major polyphenols of marjoram (Origanum majorana L.) using flash chromatography and their identification by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    PubMed

    Hossain, Mohammad B; Camphuis, Gabriel; Aguiló-Aguayo, Ingrid; Gangopadhyay, Nirupama; Rai, Dilip K

    2014-11-01

    Marjoram extracts have been separated into polar and nonpolar parts using liquid-liquid extraction. Both polar and nonpolar parts of the extracts were further fractionated by flash chromatography. The obtained fractions (90 polar and 45 nonpolar fractions) were investigated for their antioxidant activities by 2,2-diphenylpicrylhydrazyl and ferric ion reducing antioxidant power assays. A direct, positive, and linear relationship between antioxidant activity and total phenolic content of the fractions was observed. Based on antioxidant and total phenolic content data, the three fractions with the high antioxidant activities from polar and nonpolar part of the extract were analyzed for their constituent polyphenols by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Compounds were identified by matching the mass spectral data and retention time with those of authentic standards. Identification of the compounds for which there were no "in-house" standards available was carried out by accurate mass measurement of the precursor ions and product ions generated from collision-induced dissociation. Rosmarinic acid was found to be the strongest antioxidant polyphenol conferring the highest antioxidant activity to fractions 47 and 17 of polar and nonpolar part of the extract, respectively. The identification of the rosmarinic acid was further confirmed by (1) H NMR spectroscopy.

  5. Slip preference on pre-existing faults: a guide tool for the separation of heterogeneous fault-slip data in extensional stress regimes

    NASA Astrophysics Data System (ADS)

    Tranos, Markos D.

    2012-05-01

    Synthetic fault-slip data have been considered in the present paper, in order to examine through a simple graphical manner the validity and use of the widely mentioned and applied criteria such as the slip preference, slip tendency, kinematic (P and T) axes, transport orientation and strain compatibility. The examination and description concern extensional stress regimes whose greatest principal stress axis (σ1) always remains in vertical position as in Andersonian stress states. In particular, radial extension (RE), radial-pure extension (RE-PE), pure extension (PE), pure extension-transtension (PE-TRN) and transtension (TRN) are examined with the aid of the Win-Tensor stress inversion software. In all of these extensional stress regimes only extensional faults can be activated. The lower dip angle of the reactivated faults is about 40° assuming that the coefficient of friction is no smaller than 0.6. The increase of the stress ratio and/or the fault dip angle up to 70° results in the increase of the slip deviation from the normal activation. Based on the present examination of the slip preference and slip tendency in different extensional stress regimes, a new simple and practical method is proposed herein in order to separate originally heterogeneous fault-slip data into homogeneous fault groups, by which different extensional stress regimes could be determined. The application of the method on the already published fault-slip data of Lemnos Island supports its validity since over 90% the resulted fault groups and stress regimes coincide to the already published ones.

  6. Separated Shoulder

    MedlinePlus

    Separated shoulder Overview By Mayo Clinic Staff A separated shoulder is an injury to the ligaments that hold your collarbone (clavicle) to your shoulder blade. In a mild separated shoulder, the ligaments ...

  7. The Most Useful Actinide Isotope: Americium-241.

    ERIC Educational Resources Information Center

    Navratil, James D.; And Others

    1990-01-01

    Reviewed is the discovery, nuclear and chemical properties, and uses of an isotope of Americium (Am-241). Production and separation techniques used in industry are emphasized. Processes are illustrated in flow sheets. (CW)

  8. Selective photoionisation of lutetium isotopes

    SciTech Connect

    D'yachkov, Aleksei B; Kovalevich, S K; Labozin, Valerii P; Mironov, Sergei M; Panchenko, Vladislav Ya; Firsov, Valerii A; Tsvetkov, G O; Shatalova, G G

    2012-10-31

    A three-stage laser photoionisation scheme intended for enriching the {sup 176}Lu isotope from natural lutetium was considered. An investigation was made of the hyperfine structure of the second excited state 5d6s7s {yields} {sup 4}D{sub 3/2} with an energy of 37194 cm{sup -1} and the autoionisation state with an energy of 53375 cm{sup -1} of the {sup 176}Lu and {sup 175}Lu isotopes. The total electron momentum of the autoionisation level and the constant A of hyperfine magnetic interaction were determined. Due to a small value of the isotopic shift between {sup 176}Lu and {sup 175}Lu, appreciable selectivity of their separation may be achieved with individual hyperfine structure components. The first tentative enrichment of the 176Lu isotope was performed to a concentration of 60 % - 70 %. (laser applications and other topics in quantum electronics)

  9. Isotopic Changes During Digestion: Protein

    NASA Astrophysics Data System (ADS)

    Tuross, N.

    2013-12-01

    Nutrient and hydrological inputs traverse a complicated route of pH, enzymatic and cellular processes in digestion in higher animals. The end products of digestion are the starting products for biosynthesis that are often used to interpret past life-ways. Using an artificial gut system, the isotopic changes (dD, d18O, d13C and d15N) of protein are documented. Three separate protein sources are subjected to the conditions, chemical and enzymatic, found in the stomach and upper small intestine with only a small shift in the oxygen isotopic composition of the proteins observed. Middle to lower small intestine parameters produced both greater isotopic effects and significantly lower molecular weight products. The role of the gastric enterocyte and the likely involvement of the internal milieu of this cell in the isotopic composition of amino acids that are transported to the liver are reported.

  10. Ultracapacitor separator

    DOEpatents

    Wei, Chang; Jerabek, Elihu Calvin; LeBlanc, Jr., Oliver Harris

    2001-03-06

    An ultracapacitor includes two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. The electrolyte is a polar aprotic organic solvent and a salt. The porous separator comprises a wet laid cellulosic material.

  11. Laser Isotope Enrichment for Medical and Industrial Applications

    SciTech Connect

    Leonard Bond

    2006-07-01

    Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

  12. IUPAC Periodic Table of the Isotopes

    USGS Publications Warehouse

    Holden, N.E.; Coplen, T.B.; Böhlke, J.K.; Wieser, M.E.; Singleton, G.; Walczyk, T.; Yoneda, S.; Mahaffy, P.G.; Tarbox, L.V.

    2011-01-01

    For almost 150 years, the Periodic Table of the Elements has served as a guide to the world of elements by highlighting similarities and differences in atomic structure and chemical properties. To introduce students, teachers, and society to the existence and importance of isotopes of the chemical elements, an IUPAC Periodic Table of the Isotopes (IPTI) has been prepared and can be found as a supplement to this issue.

  13. Development of laser guide stars and adaptive optics for large astronomical telescopes

    SciTech Connect

    Max, C.E.; Avicola, K.; Bissinger, H.; Brase, J.M.; Gavel, D.T.; Friedman, H.; Morris, J.R.; Olivier, S.S.; Rapp, D.; Salmon, J.T.; Waltjen, K.

    1992-06-29

    We describe a feasibility experiment to demonstrate high-order adaptive optics using a sodium-layer laser guide star. We use the copper-vapor-pumped dye lasers developed for LLNL`s atomic Vapor Laser Isotope Separation program to create the laser guide star. Closed-loop adaptive corrections will be accomplished using a 69-subaperture adaptive optics system on a one-meter telescope at LLNL. The laser bream is projected upwards from a beam director approximately 5 meters away from the main telescope, and is expected to form a spot 1-2 meters in diameter at the atmospheric sodium layer (95 km altitude). We describe the overall system architecture and adaptive optics components, and analyze the expected performance. Our long-term goal is to develop sodium-layer laser guide stars and adaptive optics for large astronomical telescopes. We discuss preliminary design trade-offs for the Keck Telescope at Mauna Kea.

  14. Development of laser guide stars and adaptive optics for large astronomical telescopes

    SciTech Connect

    Max, C.E.; Avicola, K.; Bissinger, H.; Brase, J.M.; Gavel, D.T.; Friedman, H.; Morris, J.R.; Olivier, S.S.; Rapp, D.; Salmon, J.T.; Waltjen, K.

    1992-06-29

    We describe a feasibility experiment to demonstrate high-order adaptive optics using a sodium-layer laser guide star. We use the copper-vapor-pumped dye lasers developed for LLNL's atomic Vapor Laser Isotope Separation program to create the laser guide star. Closed-loop adaptive corrections will be accomplished using a 69-subaperture adaptive optics system on a one-meter telescope at LLNL. The laser bream is projected upwards from a beam director approximately 5 meters away from the main telescope, and is expected to form a spot 1-2 meters in diameter at the atmospheric sodium layer (95 km altitude). We describe the overall system architecture and adaptive optics components, and analyze the expected performance. Our long-term goal is to develop sodium-layer laser guide stars and adaptive optics for large astronomical telescopes. We discuss preliminary design trade-offs for the Keck Telescope at Mauna Kea.

  15. Isotope fractionation

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    A rash of new controversy has emerged around the subject of mass-independent isotope fractionation effects, particularly in the case of the oxygen isotopes. To be sure, the controversy has been around for awhile, but it has been given new impetus by the results of a recent study by Mark H. Thiemens and John E. Heidenreich III of the University of California, San Diego (Science, March 4, 1983).Gustav Arrhenius has been trying to convince the planetary science community that chemical effects in isotope fractionation processes could explain observations in meteorites that appear to be outside of the traditionally understood mass-dependent fractionations (G. Arrhenius, J . L. McCrumb, and N. F. Friedman, Astrophys. Space Sci, 65, 297, 1974). Robert Clayton had made the basic observations of oxygen in carbonaceous chondrites that the slope of the δ17 versus δ18 line was 1 instead of the slope of ½ characteristic of terrestrial rocks and lunar samples (Ann. Rev. Nucl. Part. Sci., 28, 501, 1978). The mass-independent effects were ascribed to the apparent contribution of an ancient presolar system component of O16.

  16. Chiral Separations

    NASA Astrophysics Data System (ADS)

    Stalcup, A. M.

    2010-07-01

    The main goal of this review is to provide a brief overview of chiral separations to researchers who are versed in the area of analytical separations but unfamiliar with chiral separations. To researchers who are not familiar with this area, there is currently a bewildering array of commercially available chiral columns, chiral derivatizing reagents, and chiral selectors for approaches that span the range of analytical separation platforms (e.g., high-performance liquid chromatography, gas chromatography, supercritical-fluid chromatography, and capillary electrophoresis). This review begins with a brief discussion of chirality before examining the general strategies and commonalities among all of the chiral separation techniques. Rather than exhaustively listing all the chiral selectors and applications, this review highlights significant issues and differences between chiral and achiral separations, providing salient examples from specific classes of chiral selectors where appropriate.

  17. Water separator

    NASA Technical Reports Server (NTRS)

    Dunn, W. F.; Austin, I. G. (Inventor)

    1964-01-01

    An apparatus for separating liquids from gases or gaseous fluids is described. Features of the apparatus include: (1) the collection and removal of the moisture in the fluid is not dependent upon, or affected by gravity; (2) all the collected water is cyclically drained from the apparatus irrespective of the attitude of the separator; and (3) a fluid actuator is utilized to remove the collected water from the separator.

  18. Battery separators.

    PubMed

    Arora, Pankaj; Zhang, Zhengming John

    2004-10-01

    The ideal battery separator would be infinitesimally thin, offer no resistance to ionic transport in electrolytes, provide infinite resistance to electronic conductivity for isolation of electrodes, be highly tortuous to prevent dendritic growths, and be inert to chemical reactions. Unfortunately, in the real world the ideal case does not exist. Real world separators are electronically insulating membranes whose ionic resistivity is brought to the desired range by manipulating the membranes thickness and porosity. It is clear that no single separator satisfies all the needs of battery designers, and compromises have to be made. It is ultimately the application that decides which separator is most suitable. We hope that this paper will be a useful tool and will help the battery manufacturers in selecting the most appropriate separators for their batteries and respective applications. The information provided is purely technical and does not include other very important parameters, such as cost of production, availability, and long-term stability. There has been a continued demand for thinner battery separators to increase battery power and capacity. This has been especially true for lithiumion batteries used in portable electronics. However, it is very important to ensure the continued safety of batteries, and this is where the role of the separator is greatest. Thus, it is essential to optimize all the components of battery to improve the performance while maintaining the safety of these cells. Separator manufacturers should work along with the battery manufacturers to create the next generation of batteries with increased reliability and performance, but always keeping safety in mind. This paper has attempted to present a comprehensive review of literature on separators used in various batteries. It is evident that a wide variety of separators are available and that they are critical components in batteries. In many cases, the separator is one of the major factors

  19. Guide to Instructional Videoconferencing.

    ERIC Educational Resources Information Center

    Matthews, Denise; Reiss, John G.

    An instructional videoconference (IVC) is an interactive delivery mechanism for long-distance communication and education, which uses 2-way audio and 1- or 2-way video to facilitate interaction between presenters and learners who are separated by significant distance. This guide, intended for the staff of federal, state, and local programs that…

  20. Plant Study Guide.

    ERIC Educational Resources Information Center

    Brynildson, Inga

    Appropriate for secondary school botany instruction, this study guide focuses on the important roles of plants in human lives. Following a rationale for learning the basic skills of a botanist, separate sections discuss the process sunlight undergoes during photosynthesis, the flow of energy in the food chain, alternative plant lifestyles, plant…

  1. SOSS User Guide

    NASA Technical Reports Server (NTRS)

    Zhu, Zhifan; Gridnev, Sergei; Windhorst, Robert D.

    2015-01-01

    This User Guide describes SOSS (Surface Operations Simulator and Scheduler) software build and graphic user interface. SOSS is a desktop application that simulates airport surface operations in fast time using traffic management algorithms. It moves aircraft on the airport surface based on information provided by scheduling algorithm prototypes, monitors separation violation and scheduling conformance, and produces scheduling algorithm performance data.

  2. Quantitative Microbial Ecology through Stable Isotope Probing

    PubMed Central

    Mau, Rebecca L.; Schwartz, Egbert; Caporaso, J. Gregory; Dijkstra, Paul; van Gestel, Natasja; Koch, Benjamin J.; Liu, Cindy M.; McHugh, Theresa A.; Marks, Jane C.; Morrissey, Ember M.; Price, Lance B.

    2015-01-01

    Bacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification to stable isotope probing (SIP) that enables the isotopic composition of DNA from individual bacterial taxa after exposure to isotope tracers to be determined. In our modification, after isopycnic centrifugation, DNA is collected in multiple density fractions, and each fraction is sequenced separately. Taxon-specific density curves are produced for labeled and nonlabeled treatments, from which the shift in density for each individual taxon in response to isotope labeling is calculated. Expressing each taxon's density shift relative to that taxon's density measured without isotope enrichment accounts for the influence of nucleic acid composition on density and isolates the influence of isotope tracer assimilation. The shift in density translates quantitatively to isotopic enrichment. Because this revision to SIP allows quantitative measurements of isotope enrichment, we propose to call it quantitative stable isotope probing (qSIP). We demonstrated qSIP using soil incubations, in which soil bacteria exhibited strong taxonomic variations in 18O and 13C composition after exposure to [18O]water or [13C]glucose. The addition of glucose increased the assimilation of 18O into DNA from [18O]water. However, the increase in 18O assimilation was greater than expected based on utilization of glucose-derived carbon alone, because the addition of glucose indirectly stimulated bacteria to utilize other substrates for growth. This example illustrates the benefit of a quantitative approach to stable isotope probing. PMID:26296731

  3. Nickel isotopes and methanogens

    NASA Astrophysics Data System (ADS)

    Neubeck, A.; Ivarsson, M.

    2013-12-01

    Methanogens require Ni for their growth and as a consequence the microbial fractionation of Ni isotopes can be used as a biomarker for activity of methanogenic communities1. Anaerobic laboratory experiments was performed using methanogens to investigate methanogenic growth in a modified nutrient media2 with olivine Fo91 (5g/l) added as an additional mineral nutrient source and as the only H2 provider. One of the investigated methanogens showed an increased growth in the experiments with added olivine. There were also a close relationship between the mobilized Ni and the growth of the methanogen. Ni is an element that previously has been neglected in the study of fossilized microorganisms and their interaction with mineral substrates and, thus, there are no records or published data of Ni in association with microfossils. However, we have detected enrichments of Ni in fossilized microorganisms and ichno-fossils, respectively, from three separate locations. Ni is not present in the host rock in any of the samples. Thus, Ni is present in association with fossilized microorganisms from environments and more extensive analysis is required to understand the magnitude, uptake, preservation and fractionation of Ni in microfossils. In order to analyze Ni isotope fractionation from microbe-mineral interaction, we plan to use a high-resolution Laser-Ablation Time-of-Flight Mass Spectrometer (LMS)3. In situ profile ablation will provide detailed and localized data on fractionation patterns between microfossils and their host rock. Also, this technique will allow us to identify the change in Ni isotopic fractionation in rock samples caused by abiotic and biogenic processes in a faster and easier way and with less risk for contamination compared to the wet chemistry analyses of Ni isotopes. 1. Cameron, V., Vance, D., Archer, C. & House, C. H. A biomarker based on the stable isotopes of nickel. Proceedings of the National Academy of Sciences 106, 10944-10948 (2009). 2. Schn

  4. Stable isotope customer list and summary of shipments, FY 1986

    SciTech Connect

    Tracy, J.G.

    1987-02-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope.

  5. Analysis of hydrogen isotope mixtures

    DOEpatents

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

  6. Hafnium isotope stratigraphy of ferromanganese crusts

    USGS Publications Warehouse

    Lee, D.-C.; Halliday, A.N.; Hein, J.R.; Burton, K.W.; Christensen, J.N.; Gunther, D.

    1999-01-01

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in 87Sr/86Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  7. Stable carbon isotope analysis of coprocessing materials

    SciTech Connect

    Burke, F.P.; Winschel, R.A.; Lancet, M.S.

    1990-05-01

    Consol R D is developing and demonstrating stable carbon isotope analysis as a method quantitatively distinguish coal-derived and petroleum-derived carbon in products from coal/petroleum coprocessing. The approach taken is to develop the method, then demonstrate its application on authentic continuous-unit products. The significance of selective isotopic fractionation is being determined and, if necessary, corrections will be applied to account for it. Activities for this quarter include: method development -- investigation of selective fractionation. Three petroleum atmospheric still bottoms (ASBs) were separated by distillation and solubility fractionation to determine the homogeneity of the carbon isotope ratios of the separated fractions. These same three petroleum ASBs and three geographically distinct coals were pyrolyzed at 800{degree}F for 30 min and hydrogenated over a CoMo catalyst at 750{degree}F for 60 min to determine the effects of these treatments on the isotopic compositions of the produce fractions. Twelve coal liquefaction oils were analyzed for carbon isotope ratios. These oils were derived from subbituminous and bituminous coals from the first- and second-stage reactors in the thermal/catalytic and modes; validation and application, analysis. Carbon isotope analyses of samples from HRI bench unit coprocessing run 238-2 (Taiheiyo coal/Maya VSB) were analyzed. A method to correct for selective isotopic fractionation was developed and applied to the data. Five coprocessing samples were analyzed at the request of SRI International. 12 refs., 15 figs., 24 tabs.

  8. Stereoisomers Separation

    NASA Astrophysics Data System (ADS)

    Wieczorek, Piotr

    The use of capillary electrophoresis for enantiomer separation and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be separated show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the separation based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers separation and determination are presented.

  9. Neutron guide

    DOEpatents

    Greene, Geoffrey L.

    1999-01-01

    A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

  10. Mist separator

    SciTech Connect

    Moran, T.M.

    1984-04-17

    An apparatus for the removal of particulates from a flowing gas stream and a process for its use are provided. A perforated screen separator formed as a plate having parallel rows of perforations formed by pushing alternating strips of the plate material forward and backward from the plane of the plate is used. The perforated screen separator may be used alone or with a fiber bed mist eliminator for increased particulate removal.

  11. Product separator

    DOEpatents

    Welsh, Robert A.; Deurbrouck, Albert W.

    1976-01-20

    A secondary light sensitive photoelectric product separator for use with a primary product separator that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate separation is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to separate from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted nothing moves on the second separator. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected separated concentrate is recovered at a maximum rate regardless of variations in the flow stream or other conditions present.

  12. Investigation of Gravity Lanthanide Separation Chemistry

    SciTech Connect

    Payne, Rosara F.; Schulte, Shannon M.; Douglas, Matthew; Friese, Judah I.; Farmer, Orville T.; Finn, Erin C.

    2011-03-01

    Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method allows parallel processing of many samples in 1.5 hours followed by 60 minute counting for quantification of 9 isotopes of 7 lanthanide elements.

  13. Method and apparatus for tritiated water separation

    DOEpatents

    Nelson, D.A.; Duncan, J.B.; Jensen, G.A.

    1995-09-19

    The present invention is a membrane method and apparatus for separating isotopic water constituents from light water. The method involves providing a supported membrane of an aromatic polyphosphazene and pressurizing the water on one side of the membrane thereby forcing the light water through the supported membrane while isotopic water constituents are retained or vice versa. The apparatus of the present invention includes an aromatic polyphosphazene placed on a porous support and means for pressurizing water through the membrane while certain isotopic water constituents are retained. 1 fig.

  14. Method and apparatus for tritiated water separation

    DOEpatents

    Nelson, David A.; Duncan, James B.; Jensen, George A.

    1995-01-01

    The present invention is a membrane method and apparatus for separating isotopic water constituents from light water. The method involves providing a supported membrane of an aromatic polyphosphazene and pressurizing the water on one side of the membrane thereby forcing the light water through the supported membrane while isotopic water constituents are retained or vice versa. The apparatus of the present invention includes an aromatic polyphosphazene placed on a porous support and means for pressurizing water through the membrane while certain isotopic water constituents are retained.

  15. Map Separates

    USGS Publications Warehouse

    ,

    2001-01-01

    U.S. Geological Survey (USGS) topographic maps are printed using up to six colors (black, blue, green, red, brown, and purple). To prepare your own maps or artwork based on maps, you can order separate black-and-white film positives or negatives for any color printed on a USGS topographic map, or for one or more of the groups of related features printed in the same color on the map (such as drainage and drainage names from the blue plate.) In this document, examples are shown with appropriate ink color to illustrate the various separates. When purchased, separates are black-and-white film negatives or positives. After you receive a film separate or composite from the USGS, you can crop, enlarge or reduce, and edit to add or remove details to suit your special needs. For example, you can adapt the separates for making regional and local planning maps or for doing many kinds of studies or promotions by using the features you select and then printing them in colors of your choice.

  16. A simulation study of linear RF ion guides for AMS

    NASA Astrophysics Data System (ADS)

    Zhao, X.-L.; Litherland, A. E.

    2015-02-01

    The use of radiofrequency multipoles and particularly the radiofrequency quadrupole (RFQ) controlled gas cell to facilitate on-line isobar separations for Accelerator Mass Spectrometry (AMS) is being explored experimentally and theoretically in a preliminary way at present. These new methods have the potential to extend greatly the analytical scope of AMS. However, there are many technical challenges to adapt an RF gas cell isobar separating device and still maintain stable and high transmission for routine AMS using the high current Cs+ sputter ion sources developed for nuclear physics and adapted to the detection of rare radioactive isotopes for AMS. An overview of linear RF ion guide properties is therefore needed to assist in the conceptualization of their efficient additions into AMS. In this work the intrinsic properties of linear RF ion guides, which are relevant to the generation of the RF induced ion energy distributions and for the evaluation of the ion transmissions in vacuum, are systematically studied using SIMION 8.1. These properties are compared among radiofrequency quadrupole, hexapole and octupole ion guides, so that their usefulness for AMS applications can be evaluated and compared. By simulation it is found that to prepare a typical RF captured AMS ion beam to within a safe range of ion energies prior to the onset of gas interactions, a higher multipole is more suitable for the first RF field receptor, while a quadrupole operated with q2 ∼ 0.5 is more suited as the final ion guide for concentrating the energy-cooled ions near axis.

  17. Process for recovery of daughter isotopes from a source material

    SciTech Connect

    Tranter, Troy J.; Todd, Terry A.; Lewis, Leroy C.; Henscheid, Joseph P.

    2005-10-04

    The invention includes a method of separating isotopes from a mixture containing at least two isotopes in a solution. A first isotope is precipitated and is collected from the solution. A daughter isotope is generated and collected from the first isotope. The invention includes a method of producing an actinium-225/bismuth-213 product from a material containing thorium-229 and thorium-232. A solution is formed containing nitric acid and the material and iodate is added to form a thorium iodate precipitate. A supernatant is separated from the thorium iodate precipitate and a second volume of nitric acid is added to the precipitate. The precipitate is stored and a decay product comprising actinium-225 and bismuth-213 is generated in the second volume of nitric acid which is then separated from the thorium iodate precipitate, filtered, and treated using at least one chromatographic procedure. The invention also includes a system for producing an actinium-225/bismuth-213 product.

  18. Calcium isotopes in wine

    NASA Astrophysics Data System (ADS)

    Holmden, C. E.

    2011-12-01

    The δ 44/40Ca values of bottled wine vary between -0.76% to -1.55% on the seawater scale and correlate weakly with inverse Ca concentration and Mg/Ca ratio, such that the lowest δ 44/40Ca values have the highest Ca concentrations and lowest Mg/Ca ratios. The correlation is notable in the sense that the measured wines include both whites and reds sampled from different wine growing regions of the world, and cover a wide range of quality. Trends among the data yield clues regarding the cause of the observed isotopic fractionation. White wines, and wines generally perceived to be of lower quality, have lower δ 44/40Ca values compared to red wines and wines of generally perceived higher quality. Quality was assessed qualitatively through sensory evaluation, price, and scores assigned by critics. The relationship between δ 44/40Ca and wine quality was most apparent when comparing wines of one varietal from one producer from the same growing region. In the vineyard, wine quality is related to factors such as the tonnage of the crop and the ripeness of the grapes at the time of harvesting, the thickness of the skins for reds, the age of the vines, as well as the place where the grapes were grown (terroir). Quality is also influenced by winemaking practices such as fermentation temperature, duration of skin contact, and barrel ageing. Accordingly, the relationship between δ 44/40Ca and wine quality may originate during grape ripening in the vineyard or during winemaking in the cellar. We tested the grape ripening hypothesis using Merlot grapes sampled from a vineyard in the Okanagan, British Columbia, using sugar content (degrees Brix) as an indicator of ripeness. The grapes were separated into pulp, skin, and pip fractions and were analyzed separately. Thus far, there is no clear evidence for a systematic change in δ 44/40Ca values associated with progressive ripening of grapes in the vineyard. On the day of harvesting, the δ 44/40Ca value of juice squeezed from

  19. Isotopically Modified Molybdenum: Production for Application in Nuclear Energy

    NASA Astrophysics Data System (ADS)

    Smirnov, A. Yu.; Bonarev, A. K.; Sulaberidze, G. A.; Borisevich, V. D.; Kulikov, G. G.; Shmelev, A. N.

    The possibility to use the isotopically modified molybdenum as a constructive material for the fuel rods of light water and fast reactors is discussed. The calculations demonstrate that the isotopically modified molybdenum with an average neutron absorption cross-section comparable to that of zirconium can be obtained with the reasonable for practice cost by a cascade of gas centrifuges, specially designed for separation of non-uranium isotopes.

  20. SEPARATION PROCESS

    DOEpatents

    Stoughton, R.W.

    1961-10-24

    A process for separating tetravalent plutonium from aqueous solutions and from niobium and zirconium by precipitation on lanthanum oxalate is described. The oxalate ions of the precipitate may be decomposed by heating in the presence of an oxidizing agent, forming a plutonium compound readily soluble in acid. (AEC)

  1. Plasma separation

    NASA Technical Reports Server (NTRS)

    Steurer, Wolfgang

    1992-01-01

    This process employs a thermal plasma for the separation and production of oxygen and metals. It is a continuous process that requires no consumables and relies entirely on space resources. The almost complete absence of waste renders it relatively clean. It can be turned on or off without any undesirable side effects or residues. The prime disadvantage is its high power consumption.

  2. Cross Section Evaluations for Arsenic Isotopes

    SciTech Connect

    Pruet, J; McNabb, D P; Ormand, W E

    2005-03-10

    The authors present an evaluation of cross sections describing reactions with neutrons incident on the arsenic isotopes with mass numbers 75 and 74. Particular attention is paid to (n,2n) reactions. The evaluation for {sup 75}As, the only stable As isotope, is guided largely by experimental data. Evaluation for {sup 74}As is made through calculations with the EMPIRE statistical-model reaction code. Cross sections describing the production and destruction of the 26.8 ns isomer in {sup 74}As are explicitly considered. Uncertainties and covariances in some evaluated cross sections are also estimated.

  3. Isotope distribution program at the Oak Ridge National Laboratory with emphasis on medical isotopes

    SciTech Connect

    Adair, H.L.

    1987-02-26

    The Isotope Distribution Program (IDP) is a group of individual activities with separate and diverse DOE sponsors which share the common mission of the production and distribution of isotope products and the performance of isotope-related services. Its basic mission is to provide isotope products and associated services to the user community by utilizing government-owned facilities that are excess to the primary mission of the DOE. The IDP is in its 41st year of operation. Initially, the program provided research quantities of radioactive materials, and through the 1950's it was the major supplier of radioisotopes for both research and commercial application. Distribution of enriched stable isotopes began in 1954. This paper discusses the use of radioisotopes in medicine and the role that ORNL plays in this field.

  4. Gas separating

    DOEpatents

    Gollan, Arye Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  5. Gas separating

    DOEpatents

    Gollan, Arye

    1988-01-01

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  6. Dust separator

    SciTech Connect

    Borow, H.

    1987-01-27

    This patent describes a gas filter apparatus for separating solids from a gas stream comprising a housing having a top, base, and side walls defining a chamber, a partition wall extending across the chamber and separating the chamber into an upper compartment and a lower compartment. A gas inlet conveyor tube in the chamber passes downwardly of the partition and into the lower compartment, the portion of the conveyor tube passing through the upper compartment being impervious and the portion of the conveyor tube extending downwardly into the lower compartment being provided with exit means including exit apertures at least in the area of the conveyor tube adjacent the partition wall. The partition wall is provided with openings surrounding the conveyor tube and communicates the lower compartment with the upper compartment. A filter means in the form of filter tubes covers each opening in the partition wall and extends downwardly in the lower compartment and parallel to the conveyor tube, at least one gas outlet communicating with the upper compartment. A suction means is associated with the gas outlet to provide a reduced pressure within the chamber. A discharge means at the base of the housing is associated with the lower compartment for discharging solid matter separated from the gas stream. The solid laden gas is conveyed into the lower compartment downwardly by the conveying tube and the gas of the stream is drawn from the conveyor tube immediately past the partition, through the surrounding filter tubes in order to prevent the formation of counter gas flows to the gravity discharge of the solids being separated from the gas stream.

  7. Separation system

    DOEpatents

    Rubin, Leslie S.

    1986-01-01

    A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. Separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.

  8. High-accuracy determination of iron in seawater by isotope dilution multiple collector inductively coupled plasma mass spectrometry (ID-MC-ICP-MS) using nitrilotriacetic acid chelating resin for pre-concentration and matrix separation.

    PubMed

    de Jong, Jeroen; Schoemann, Véronique; Lannuzel, Delphine; Tison, Jean-Louis; Mattielli, Nadine

    2008-08-15

    In the present paper we describe a robust and simple method to measure dissolved iron (DFe) concentrations in seawater down to <0.1 nmol L(-1) level, by isotope dilution multiple collector inductively coupled plasma mass spectrometry (ID-MC-ICP-MS) using a (54)Fe spike and measuring the (57)Fe/(54)Fe ratio. The method provides for a pre-concentration step (100:1) by micro-columns filled with the resin NTA Superflow of 50 mL seawater samples acidified to pH 1.9. NTA Superflow is demonstrated to quantitatively extract Fe from acidified seawater samples at this pH. Blanks are kept low (grand mean 0.045+/-0.020 nmol L(-1), n=21, 3 x S.D. limit of detection per session 0.020-0.069 nmol L(-1) range), as no buffer is required to adjust the sample pH for optimal extraction, and no other reagents are needed than ultrapure nitric acid, 12 mM H(2)O(2), and acidified (pH 1.9) ultra-high purity (UHP) water. We measured SAFe (sampling and analysis of Fe) reference seawater samples Surface-1 (0.097+/-0.043 nmol L(-1)) and Deep-2 (0.91+/-0.17 nmol L(-1)) and obtained results that were in excellent agreement with their DFe consensus values: 0.118+/-0.028 nmol L(-1) (n=7) for Surface-1 and 0.932+/-0.059 nmol L(-1) (n=9) for Deep-2. We also present a vertical DFe profile from the western Weddell Sea collected during the Ice Station Polarstern (ISPOL) ice drift experiment (ANT XXII-2, RV Polarstern) in November 2004-January 2005. The profile shows near-surface DFe concentrations of approximately 0.6 nmol L(-1) and bottom water enrichment up to 23 nmol L(-1) DFe.

  9. Stable isotopic characterisation of francolite formation

    NASA Astrophysics Data System (ADS)

    McArthur, J. M.; Benmore, R. A.; Coleman, M. L.; Soldi, C.; Yeh, H.-W.; O'Brien, G. W.

    1986-02-01

    Stable isotopic data are presented for 112 samples of francolite from 18 separate phosphate deposits. Values of δ 13C and δ 34S in most offshore deposits suggest formation within oxic or suboxic environments either by carbonate replacement or direct precipitation of francolite from water of normal marine compositions. The exceptions are concretionary francolite from Namibia, which has an isotopic composition in keeping with its formation within organic-rich sediments, and that from offshore Morocco, which has an isotopic signature of the anoxic/suboxic interface. Onshore deposits from Jordan, Mexico, South Africa and, possibly, the Permian Phosphoria Formation in the western U.S.A., are substantially depleted in 18O: they appear to be too altered for deductions to be made about their environments of formation. In other onshore deposits which are unaltered, or minimally altered, the isotopic composition suggests that some formed within sulphate-reducing sediments (Sedhura, Morocco) whilst francolite from the Georgina Basin of Australia formed at the oxic/anoxic boundary, where oxidation of biogenic H 2S decreases the δ 34S of pore water. In general, pelletal samples show non-oxic isotopic signatures, whilst non-pelletal samples show oxic isotopic signatures, but samples from Namibia, Peru (Ica Plateau) and the Californian and Moroccan margins are exceptions to this rule. Morphology may therefore be a misleading indicator of francolite genesis as no definitive relation exists between phosphorite type and isotopic signature.

  10. Progress in isotope tracer hydrology in Canada

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.; Edwards, T. W. D.; Birks, S. J.; St Amour, N. A.; Buhay, W. M.; McEachern, P.; Wolfe, B. B.; Peters, D. L.

    2005-01-01

    An overview of current research in isotope hydrology, focusing on recent Canadian contributions, is discussed under the headings: precipitation networks, hydrograph separation and groundwater studies, river basin hydrology, lake and catchment water balance, and isotope palaeohydrology from lake sediment records. Tracer-based techniques, relying primarily on the naturally occurring environmental isotopes, have been integrated into a range of hydrological and biogeochemical research programmes, as they effectively complement physical and chemical techniques. A significant geographic focus of Canadian isotope hydrology research has been on the Mackenzie River basin, forming contributions to programmes such as the Global Energy and Water Cycle Experiment. Canadian research has also directly supported international efforts such as the International Atomic Energy Agency's (IAEA) Global Network for Isotopes in Precipitation and IAEAs Coordinated Research Project on Large River Basins. One significant trend in Canadian research is toward sustained long-term monitoring of precipitation and river discharge to enable better characterization of spatial and temporal variability in isotope signatures and their underlying causes. One fundamental conclusion drawn from previous studies in Canada is that combined use of 18O and 2H enables the distinction of precipitation variability from evaporation effects, which offers significant advantages over use of the individual tracers alone. The study of hydrological controls on water chemistry is one emerging research trend that stems from the unique ability to integrate isotope sampling within both water quality and water quantity surveys. Copyright

  11. Discovery Guide.

    ERIC Educational Resources Information Center

    Edwards, Claudia

    This guide describes a project (Teamwork Approach to Better Schools) developed to promote the establishment of a formal teacher support network in a variety of schools within a local support district. The model is a guide to newcomers to the project, helping eliminate startup problems and providing a sound base of experiences. The program began…

  12. Separation processes using expulsion from dilute supercritical solutions

    DOEpatents

    Cochran, H.D. Jr.

    1993-04-20

    A process is described for separating isotopes as well as other mixtures by utilizing the behavior of dilute repulsive or weakly attractive elements of the mixtures as the critical point of the solvent is approached.

  13. Separation processes using expulsion from dilute supercritical solutions

    DOEpatents

    Cochran, Jr., Henry D.

    1993-01-01

    A process for separating isotopes as well as other mixtures by utilizing the behavior of dilute repulsive or weakly attractive elements of the mixtures as the critical point of the solvent is approached.

  14. Gas separating

    DOEpatents

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  15. Gas separating

    DOEpatents

    Gollan, A.Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  16. Isotope reference materials

    USGS Publications Warehouse

    Coplen, Tyler B.

    2010-01-01

    Measurement of the same isotopically homogeneous sample by any laboratory worldwide should yield the same isotopic composition within analytical uncertainty. International distribution of light element isotopic reference materials by the International Atomic Energy Agency and the U.S. National Institute of Standards and Technology enable laboratories to achieve this goal.

  17. Statistical clumped isotope signatures

    PubMed Central

    Röckmann, T.; Popa, M. E.; Krol, M. C.; Hofmann, M. E. G.

    2016-01-01

    High precision measurements of molecules containing more than one heavy isotope may provide novel constraints on element cycles in nature. These so-called clumped isotope signatures are reported relative to the random (stochastic) distribution of heavy isotopes over all available isotopocules of a molecule, which is the conventional reference. When multiple indistinguishable atoms of the same element are present in a molecule, this reference is calculated from the bulk (≈average) isotopic composition of the involved atoms. We show here that this referencing convention leads to apparent negative clumped isotope anomalies (anti-clumping) when the indistinguishable atoms originate from isotopically different populations. Such statistical clumped isotope anomalies must occur in any system where two or more indistinguishable atoms of the same element, but with different isotopic composition, combine in a molecule. The size of the anti-clumping signal is closely related to the difference of the initial isotope ratios of the indistinguishable atoms that have combined. Therefore, a measured statistical clumped isotope anomaly, relative to an expected (e.g. thermodynamical) clumped isotope composition, may allow assessment of the heterogeneity of the isotopic pools of atoms that are the substrate for formation of molecules. PMID:27535168

  18. Variations of the isotopic composition of sulfur in enstatite and ordinary chondrites

    NASA Technical Reports Server (NTRS)

    Gao, Xia; Thiemens, Mark H.

    1993-01-01

    High-precision sulfur isotopic analyses (delta S-33, delta S-34, and delta S-36) of bulk ordinary and enstatite chondrites demonstrate that systematic variations exist. The average delta S-34 values are -0.26 +/- 0.07, -0.02 +/- 0.06, and 0.49 +/- 0.16 percent for enstatite and ordinary and carbonaceous chondrites, respectively. Isotopic variations of different sample specimens of primitive meteorites, e.g., Qingzhen and Abee, were observed which may be attributed to heterogeneity in the early solar nebula. Sulfur isotopic fractionations in both bulk samples and mineral separates are mass-dependent, and no nuclear isotopic anomalies were detected. The sulfur isotopic compositions of both mineral and density separates were measured. The sulfur isotopic compositions of separated chondrules from Chainpur and Bjurbole are reported. Significant isotopic difference for the chondrules from the bulk meteorite are noted for both meteorites.

  19. Pb isotopic heterogeneity in basaltic phenocrysts

    SciTech Connect

    Bryce, Julia G.; DePaolo, Donald J.

    2002-06-01

    The Pb isotopic compositions of phenocrystic phases in young basaltic lavas have been investigated using the Getty-DePaolo method (Getty S. J. and DePaolo D. J. [1995] Quaternary geochronology by the U-Th-Pb method. Geochim. Cosmochim. Acta 59, 3267 3272), which allows for the resolution of small isotopic differences. Phenocryst, matrix, and whole rock analyses were made on samples from the 17 Myr-old Imnaha basalts of the Columbia River Group, a zero-age MORB from the Mid-Atlantic Ridge, and a ca. 260 kyr-old tholeiite from Mount Etna. Plagioclase feldspar phenocrysts have low-(U, Th)/Pb, and in each sample the plagioclase has significantly lower 206Pb/207Pb and 208Pb/207Pb values than whole rock, matrix, and magnetite-rich separates. The Pb isotopic contrast between plagioclase and matrix/whole rock is found in three samples with varying grain sizes (0.5 2 cm for the Imnaha basalt and MORB and <1 mm for the Etna sample) from different tectonic settings, suggesting that these results are not unique. The isotopic contrasts are only slightly smaller in magnitude than the variations exhibited by whole rock samples from the region. The Imnaha basalts also have Sr isotopic heterogeneity evident only in plagioclase phenocrysts, but the MORB and Etna lavas do not. The isotopic heterogeneities reflect magma mixing, and indicate that isotopically diverse magmas were mixed together just prior to eruption. The results reinforce indications from melt inclusion studies that magma source region isotopic heterogeneities have large amplitudes at short length scales, and that the isotopic variations imparted to the magmas are not entirely homogenized during segregation and transport processes.

  20. Oxygen Isotopic Compositions of Fulgurites

    NASA Astrophysics Data System (ADS)

    Robert, F.; Javoy, M.

    1992-07-01

    Two occurrences of vitreous rocks (fulgurites) that have resulted from the fusion of Etnean lavas, have been ascribed to the result of lightning striking the basalts and melting fresh volcanic rocks [1]. Rapidly quenched melts appear as tubular cavities that preserve the path of the discharge. Glass droplets (D <= 500 micrometers) are always dispersed around the fused lava tube and show several petrographic similarities with chondrules found in ordinary chondrites (presence of melilite, radiating skeletal fassaite, etc). In this process, high temperatures (T>1800 K) have probably been reached during timescales <=10 sec. Because it has been suggested that lightning discharges may have played an important role in the formation of chondrules [2], we have analyzed the oxygen isotope compositions of these fulgurites (our experimental protocol is described elsewhere [3]). The glass (free from any contamination from the unmelted basalt) is 1.5o/oo depleted in ^18O relative to its measured initial isotopic composition (delta^18O = +5.6o/oo); most of the data define a mass-dependent fractionation relationship (i.e. delta^17O = 0.52 x delta^18O). Therefore the data clearly do not reproduce the oxygen isotope anomaly defined for meteorites, which has a slope of 1 in the diagram delta^17O versus delta^18O (i.e. delta^17O = 1.0 x delta^18O). Nevertheless, it should be noted that some glass samples scatter around this canonical value of 0.52 with minor departures from a purely mass-dependent fractionation. If these results are confirmed by additional determinations (now in progress) on the separated glassy droplets, the following conclusions can be proposed: 1) lightning discharges do not yield oxygen isotope anomalies similar to those measured in chondrules and 2) an isotope exchange between hot chondrules and their parent nebular gas--presumably "anomalous" in its oxygen isotopes-- seems difficult to achieve within the duration of the rapid cooling of the melt. This last point

  1. Maximum Entropy Guide for BSS

    NASA Astrophysics Data System (ADS)

    Górriz, J. M.; Puntonet, C. G.; Medialdea, E. G.; Rojas, F.

    2005-11-01

    This paper proposes a novel method for Blindly Separating unobservable independent component (IC) Signals (BSS) based on the use of a maximum entropy guide (MEG). The paper also includes a formal proof on the convergence of the proposed algorithm using the guiding operator, a new concept in the genetic algorithm (GA) scenario. The Guiding GA (GGA) presented in this work, is able to extract IC with faster rate than the previous ICA algorithms, based on maximum entropy contrast functions, as input space dimension increases. It shows significant accuracy and robustness than the previous approaches in any case.

  2. Search for unknown isotopes using the JAERI-ISOL

    NASA Astrophysics Data System (ADS)

    Ichikawa, S.; Tsukada, K.; Oura, Y.; Iimura, H.; Nishinaka, I.; Hatsukawa, Y.; Nagame, Y.; Asai, M.; Osa, A.; Kojima, Y.; Hirose, T.; Kawade, K.; Ohyama, T.; Sueki, K.

    1996-04-01

    A search for unknown neutron-rich rare-earth isotopes and neutron-deficient americium isotopes was carried out using a gas-jet coupled thermal ion source installed in the JAERI on-line isotope separator (JAERI-ISOL). New isotopes b166Tb and d165Gd produced in the proton-induced fission of 238U were identified. The half-lives were 21+/-6 s for b166Tb and 10.3+/-1.6 s for d.165Gd. Pu KX-rays associated with EC decays of americium isotopes produced in heavy-ion induced reactions were observed in the X/γ-ray spectra for the mass separated fraction of 237 and 236.

  3. Particle separator

    DOEpatents

    Hendricks, Charles D.

    1990-01-01

    Method and apparatus (10) are provided for separating and classifying particles (48,50,56) by dispersing the particles within a fluid (52) that is upwardly flowing within a cone-shaped pipe (12) that has its large end (20) above its small end (18). Particles of similar size and shape (48,50) migrate to individual levels (A,B) within the flowing fluid. As the fluid is deflected by a plate (42) at the top end of the pipe (12), the smallest particles are collected on a shelf-like flange (40). Ever larger particles are collected as the flow rate of the fluid is increased. To prevent particle sticking on the walls (14) of the pipe (12), additional fluid is caused to flow into the pipe (12) through holes (68) that are specifically provided for that purpose. Sticking is further prevented by high frequency vibrators (70) that are positioned on the apparatus (10).

  4. Particle separation

    DOEpatents

    Moosmuller, Hans [Reno, NV; Chakrabarty, Rajan K [Reno, NV; Arnott, W Patrick [Reno, NV

    2011-04-26

    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.

  5. Particle separation

    NASA Technical Reports Server (NTRS)

    Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)

    2011-01-01

    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.

  6. Colostomy Guide

    MedlinePlus

    ... Side Effects Managing Cancer-related Side Effects Ostomies Colostomy Guide Colostomy surgery is done for many different diseases and problems. Some colostomies are done because of cancer; others are not. ...

  7. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.; Kiesling, J.D.

    1963-06-11

    A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

  8. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.

    1962-01-01

    A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

  9. Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

    NASA Astrophysics Data System (ADS)

    Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

    2011-12-01

    Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

  10. Isotopic Fractionation of Selenium Oxyanions in Wetlands

    NASA Astrophysics Data System (ADS)

    Clark, S. K.; Johnson, T. M.

    2004-05-01

    As oxic surface waters pass through aquatic macrophytes and over anoxic sediments in wetlands and lakes, the dissolved Se load often decreases; and, Se isotope ratio measurements can provide information about the mechanisms involved. Previous work on microbially induced isotopic fractionation of Se oxyanions under nearly natural conditions using wetland sediments shows consistent Se isotopic shifts during reduction of Se(VI) and Se(IV) to insoluble Se(0). However, previous isotopic studies of total dissolved selenium in wetlands found little to no isotopic shift as dissolved selenium concentrations decreased. This suggests that plant/algal uptake, followed by deposition and degradation, is the primary route of Se transfer into sediments. However, it is possible that the effective isotopic fractionation between Se in the surface water and Se deposited into sediments is somehow much less than the fractionation induced by the reduction reaction, or that cycling of organically bound Se is involved. In this study, we report Se isotope data for Se(VI), Se(IV) and total dissolved Se, Se(T), in surface waters from three wetland/lake sites: Sweitzer Lake, CO; 33-Mile Reservoir, WY; and, a small pond adjacent to Benton Lake, MT. We isolated Se(IV) via hydride generation, and Se(VI) via ion exchange. Se(T), including any organic components, was also analyzed. Isotope analysis was performed on an Isoprobe MC-ICPMS, using a method modified from that of Rouxel et al. (2002). We used the 82Se + 74Se double spike approach, and spiked samples before species separation. Our results for all three locations indicate similar trends in concentration changes and isotopic shifts between the inflow and outflow waters. Se(T) concentrations decrease by 45-70%, and Se(VI) concentrations decrease by 60-90%, whereas Se(IV) concentrations increase by 60-150%. Concomitant 80Se/76Se shifts are +0.5-0.8‰ for Se(T); -0.1-0.5‰ for Se(VI); and +0.4-6.5‰ for Se(IV). These data provide greater

  11. Isotope shifts in methane near 6000/cm

    NASA Technical Reports Server (NTRS)

    Fox, K.; Halsey, G. W.; Jennings, D. E.

    1976-01-01

    Isotope shifts for cleanly resolved vibrational-rotational absorption lines of CH4-12 and CH4-13 were measured by a 5-m focal length Littrow spectrometer in the 6000/cm range. The methane isotopes were held in separate absorption cells: 20 torr of CH4-13 in a 1-m cell, and 5 torr of CH4-12 in a White cell of 4-m optical path length. Measured shifts for the cleanly resolved singlets R(0), R(1), Q(1) and P(1) are summarized in tabular form.

  12. Method for sequential injection of liquid samples for radioisotope separations

    DOEpatents

    Egorov, Oleg B.; Grate, Jay W.; Bray, Lane A.

    2000-01-01

    The present invention is a method of separating a short-lived daughter isotope from a longer lived parent isotope, with recovery of the parent isotope for further use. Using a system with a bi-directional pump and one or more valves, a solution of the parent isotope is processed to generate two separate solutions, one of which contains the daughter isotope, from which the parent has been removed with a high decontamination factor, and the other solution contains the recovered parent isotope. The process can be repeated on this solution of the parent isotope. The system with the fluid drive and one or more valves is controlled by a program on a microprocessor executing a series of steps to accomplish the operation. In one approach, the cow solution is passed through a separation medium that selectively retains the desired daughter isotope, while the parent isotope and the matrix pass through the medium. After washing this medium, the daughter is released from the separation medium using another solution. With the automated generator of the present invention, all solution handling steps necessary to perform a daughter/parent radionuclide separation, e.g. Bi-213 from Ac-225 "cow" solution, are performed in a consistent, enclosed, and remotely operated format. Operator exposure and spread of contamination are greatly minimized compared to the manual generator procedure described in U.S. patent application Ser. No. 08/789,973, now U.S. Pat. No. 5,749,042, herein incorporated by reference. Using 16 mCi of Ac-225 there was no detectable external contamination of the instrument components.

  13. Nickel isotopic composition of the mantle

    NASA Astrophysics Data System (ADS)

    Gall, Louise; Williams, Helen M.; Halliday, Alex N.; Kerr, Andrew C.

    2017-02-01

    This paper presents a detailed high-precision study of Ni isotope variations in mantle peridotites and their minerals, komatiites as well as chondritic and iron meteorites. Ultramafic rocks display a relatively large range in δ60 Ni (permil deviation in 60 Ni /58 Ni relative to the NIST SRM 986 Ni isotope standard) for this environment, from 0.15 ± 0.07‰ to 0.36 ± 0.08‰, with olivine-rich rocks such as dunite and olivine cumulates showing lighter isotope compositions than komatiite, lherzolite and pyroxenite samples. The data for the mineral separates shed light on the origin of these variations. Olivine and orthopyroxene display light δ60 Ni whereas clinopyroxene and garnet are isotopically heavy. This indicates that peridotite whole-rock δ60 Ni may be controlled by variations in modal mineralogy, with the prediction that mantle melts will display variable δ60 Ni values due to variations in residual mantle and cumulate mineralogy. Based on fertile peridotite xenoliths and Phanerozoic komatiite samples it is concluded that the upper mantle has a relatively homogeneous Ni isotope composition, with the best estimate of δ60Nimantle being 0.23 ± 0.06‰ (2 s.d.). Given that >99% of the Ni in the silicate Earth is located in the mantle, this also defines the Ni isotope composition of the Bulk Silicate Earth (BSE). This value is nearly identical to the results obtained for a suite of chondrites and iron meteorites (mean δ60 Ni 0.26 ± 0.12‰ and 0.29 ± 0.10‰, respectively) showing that the BSE is chondritic with respect to its Ni isotope composition, with little to no Ni mass-dependent isotope fractionation resulting from core formation.

  14. Isotope shift measurements on the D1 line in francium isotopes at TRIUMF

    NASA Astrophysics Data System (ADS)

    Collister, R.; Tandecki, M.; Gwinner, G.; Behr, J. A.; Pearson, M. R.; Gomez, E.; Aubin, S.; Zhang, J.; Orozco, L. A.

    2013-05-01

    Francium is the heaviest alkali and has no stable isotopes. The longest-lived among them, with half-lives from seconds to a few minutes, are now available in the new Francium Trapping Facility at TRIUMF, Canada, for future weak interaction studies. We present isotope shift measurements on the 7S1 / 2 --> 7P1 / 2 (D 1) transition on three isotopes, 206, 207 and 213 in a magneto-optical trap. The shifts are measured using a c.w. Ti:sapphire laser locked to a stabilized cavity at the mid-point between two hyperfine transitions of the reference isotope 209Fr. Scanning tunable microwave sidebands locate transitions in the other isotopes. In combination with the D 2 isotope shifts, analysis can provide a separation of the field shift, due to a changing nuclear charge radius, and specific mass shift, due to changing electron correlations, in these isotopes. Work supported by NSERC and NRC from Canada, NSF and DOE from USA, CONYACT from Mexico.

  15. Rapid separation of fresh fission products (draft)

    SciTech Connect

    Dry, D. E.; Bauer, E.; Petersen, L. A.

    2003-01-01

    The fission of highly eruiched uranium by thermal neutrons creates dozens of isotopic products. The Isotope and Nuclear Chemistry Group participates in programs that involve analysis of 'fiesh' fission products by beta counting following radiochemical separations. This is a laborious and time-consuming process that can take several days to generate results. Gamma spectroscopy can provide a more immediate path to isolopic activities, however short-lived, high-yield isotopes can swamp a gamma spectrum, making difficult the identification and quantification of isotopes on the wings and valley of the fission yield curve. The gamma spectrum of a sample of newly produced fission products is dominated by the many emissions of a very few high-yield isotopes. Specilkally, {sup 132}Te (3.2 d), its daughter, {sup 132}I(2 .28 h), {sup 140}Ba (12.75 d), and its daughter {sup 140}La (1.68 d) emit at least 18 gamma rays above 100 keV that are greater than 5% abundance. Additionally, the 1596 keV emission fiom I4'La imposes a Compton background that hinders the detection of isotopes that are neither subject to matrix dependent fractionation nor gaseous or volatile recursors. Some of these isotopes of interest are {sup 111}Ag, {sup 115}Cd, and the rare earths, {sup 153}Sm, {sup 154}Eu, {sup 156}Eu, and {sup 160}Tb. C-INC has performed an HEU irradiation and also 'cold' carrier analyses by ICP-AES to determine methods for rapid and reliable separations that may be used to detect and quantify low-yield fission products by gamma spectroscopy. Results and progress will be presented.

  16. Guide star probabilities

    NASA Technical Reports Server (NTRS)

    Soneira, R. M.; Bahcall, J. N.

    1981-01-01

    Probabilities are calculated for acquiring suitable guide stars (GS) with the fine guidance system (FGS) of the space telescope. A number of the considerations and techniques described are also relevant for other space astronomy missions. The constraints of the FGS are reviewed. The available data on bright star densities are summarized and a previous error in the literature is corrected. Separate analytic and Monte Carlo calculations of the probabilities are described. A simulation of space telescope pointing is carried out using the Weistrop north galactic pole catalog of bright stars. Sufficient information is presented so that the probabilities of acquisition can be estimated as a function of position in the sky. The probability of acquiring suitable guide stars is greatly increased if the FGS can allow an appreciable difference between the (bright) primary GS limiting magnitude and the (fainter) secondary GS limiting magnitude.

  17. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  18. PINS Spectrum Identification Guide

    SciTech Connect

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

  19. Educator's Purchasing Guide. Fifth Edition.

    ERIC Educational Resources Information Center

    Cattaneo, E. R., Ed.

    This guide contains lists of publishers of various kinds of instructional materials, textbooks and printed materials; audiovisual instructional materials; atlases, globes, maps, and accessories; tests, testing aids and services; and educational equipment and supplies. Each of these types is listed in a separate section, and each section is…

  20. Graphics Design Technology Curriculum Guide.

    ERIC Educational Resources Information Center

    Idaho State Dept. of Education, Boise. Div. of Vocational Education.

    This Idaho secondary education curriculum guide provides lists of tasks, performance objectives, and enabling objectives for instruction intended to impart entry-level employment skills in graphics design technology. The first list states all tasks for 11 areas; separate lists for each area follow. Each task on the lists is accompanied by a…

  1. Education Careers: Teacher Resource Guide.

    ERIC Educational Resources Information Center

    Texas Tech Univ., Lubbock. Curriculum Center for Family and Consumer Sciences.

    This teacher resource guide is an instructional resource for these three separate courses: exploring education careers, elementary school teacher assistant, and elementary school teaching internship. (Exploring education careers is designed as a field-based internship that provides students a background knowledge of child and adolescent…

  2. Stable Isotope Systematics of Martian Perchlorate

    NASA Astrophysics Data System (ADS)

    Martin, P.; Farley, K. A.; Archer, D., Jr.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairen, A.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

    2015-12-01

    Chlorine isotopic compositions in HCl released during evolved gas analysis (EGA) runs have been detected by the Sample Analysis at Mars (SAM) instrument on the Curiosity rover ranging from approximately -9‰ to -50‰ δ37Cl, with two spatially and isotopically separated groups of samples averaging -15‰ and -45‰. These extremely low values are the first such detection of any known natural material; common terrestrial values very rarely exceed ±5‰, and the most extreme isotopic signature yet detected elsewhere in the solar system are values of around +24‰ on the Moon. The only other known location in the solar system with large negative chlorine isotopes is the Atacama Desert, where perchlorate with -14‰ δ37Cl has been detected. The Atacama perchlorate has unusual Δ17O signatures associated with it, indicating a formation mechanism involving O3, which suggests an atmospheric origin of the perchlorate and associated large isotopic anomalies. Identification of non-zero positive Δ17O signatures in the O2 released during EGA runs would allow definitive evidence for a similar process having occurred on Mars. Perchlorate is thought to be the most likely source of HCl in EGA runs due to the simultaneous onset of O2 release. If perchlorate is indeed the HCl source, atmospheric chemistry could be responsible for the observed isotopic anomalies, with variable extents of perchlorate production producing the isotopic variability. However, chloride salts have also been observed to release HCl upon heating; if the timing of O2 release is merely coincidental, observed HCl could be coming from chlorides. At thermodynamic equilibrium, the fractionation factor of perchlorate reduction is 0.93, meaning that differing amounts of post-deposition reduction of isotopically normal perchlorate to chloride could account for the highly variable Cl isotopes. Additionally, post-deposition reduction could account for the difference between the two Cl isotopic groups if perchlorate

  3. [Baseflow separation methods in hydrological process research: a review].

    PubMed

    Xu, Lei-Lei; Liu, Jing-Lin; Jin, Chang-Jie; Wang, An-Zhi; Guan, De-Xin; Wu, Jia-Bing; Yuan, Feng-Hui

    2011-11-01

    Baseflow separation research is regarded as one of the most important and difficult issues in hydrology and ecohydrology, but lacked of unified standards in the concepts and methods. This paper introduced the theories of baseflow separation based on the definitions of baseflow components, and analyzed the development course of different baseflow separation methods. Among the methods developed, graph separation method is simple and applicable but arbitrary, balance method accords with hydrological mechanism but is difficult in application, whereas time series separation method and isotopic method can overcome the subjective and arbitrary defects caused by graph separation method, and thus can obtain the baseflow procedure quickly and efficiently. In recent years, hydrological modeling, digital filtering, and isotopic method are the main methods used for baseflow separation.

  4. Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems

    SciTech Connect

    Nimz, G. J., LLNL

    1998-06-01

    also be treated as a mostly closed system for mass balance considerations. It is the near closure of the system that permits well- constrained chemical mass balance calculations to be made. These calculations generally focus of lithogenic solutes, and therefore in our discussions of lithogenic nuclides in the paper, the concept of chemical mass balance in a nearly dosed system will play an important role. Examination of the isotopic compositions of solutes provides a better understanding of the variety of processes controlling mass balance. It is with this approach that we examined the variety of processes occurring within the catchment system, such as weathering and soil production, generation of stormflow and streamflow (hydrograph separation), movement of soil pore water, groundwater flow, and the overall processes involved with basinal water balance. In this paper, the term `nuclide` will be used when referring to a nuclear species that contains a particular number of protons and neutrons. The term is not specific to any element. The term `isotope` will be used to distinguish nuclear species of a given element (atoms with the same number of protons). That is to say, there are many nuclides in nature - for example, {sup 36}Cl, {sup 87}Sr, {sup 238}U; the element has four naturally-occurring isotopes - {sup 87}Sr, and {sup 88}Sr. This paper will first discuss the general principles that underlie the study of lithogenic and cosmogenic nuclides in hydrology, and provide references to some of the more important studies applying these principles and nuclides. We then turn in the second section to a discussion of their specific applications in catchment- scale systems. The final section of this paper discusses new directions in the application of lithogenic and cosmogenic nuclides to catchment hydrology, with some thoughts concerning possible applications that still remain unexplored.

  5. Thorium isotopic analysis by alpha spectrometry.

    PubMed

    Gingell, T

    2001-01-01

    The technique of alpha spectrometry is used to detect alpha particles and to determine their energy. In this way the technique is able to provide simultaneously quantitative information (i.e. the activity) and qualitative information (the identity) on any radionuclide that emits an alpha particle. The longer-lived naturally occurring isotopes of thorium are all alpha emitters so the technique can be used to quantify them directly and this is extremely important if radiation doses due to intakes of these isotopes into the body are to be accurately assessed. The principle of the technique is discussed, its advantages and disadvantages, and the instrumentation that is commonly used today. The need for radiochemical separation is discussed and illustrated by reference to analysis procedures in current use for thorium isotopic analysis. Practical issues such as detection limits, quality control procedures. sample throughput and cost will be covered.

  6. Homebuyer's Guide.

    ERIC Educational Resources Information Center

    Sindt, Roger P.; Harris, Jack

    Designed to assist prospective buyers in making such important decisions as whether to buy a new or older home and within what price range, the guide provides information on the purchase process. Discussion of the purchase process covers the life-cycle costs (recurring homeownership costs that must be met every month); selection of a home;…

  7. Teachers Guide.

    ERIC Educational Resources Information Center

    Linsky, Ronald B.; Schnitger, Ronald L.

    This guide provides teachers with copies of the materials given to students participating in the oceanography program of the Orange County Floating Laboratory Program and provides information concerning colleges and universities offering courses in oceanography and marine science, source of films, and sources of publications concerning the Navy's…

  8. Persuasion Guide.

    ERIC Educational Resources Information Center

    1971

    In this teacher's guide to the textbook called "Persuasion" the emphasis is on assisting the teacher to develop in his students the skills of critical and creative thinking. Each instructional unit moves from the experience of persuasive techniques, through critical analysis, to the creative practice of the technique in question. Essays on…

  9. Instructor Guide.

    ERIC Educational Resources Information Center

    Langer, Philip; Borg, Walter R.

    This Instructor Guide is designed to acquaint the teacher educator with the Utah State University Protocol Project training materials. It deals with the protocol materials generally and with each module specifically, including the following: (a) an introduction to, and rationale for protocol modules; (b) ways of identifying specific kinds of…

  10. Discovery of the krypton isotopes

    SciTech Connect

    Heim, M.; Fritsch, A.; Schuh, A.; Shore, A.; Thoennessen, M.

    2010-07-15

    Thirty-two krypton isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  11. Intracellular Cadmium Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  12. Isotope ratio determination in boron analysis.

    PubMed

    Sah, R N; Brown, P H

    1998-01-01

    method of choice for B isotope ratio determination. The current state of instrumental capabilities is adequate for B isotope determination. However, precision and accuracy are primarily limited by sample preparation, introduction, and analytical methodology, including 1. Analyte loss and isotope fractionation during sample preparation. 2. The precision of B isotope determination in small samples, especially those containing low concentrations. 3. Difficult matrices. 4. Memory effects. Sample preparation by alkali fusion allows rapid and complete decomposition of hard-to-digest samples, but high-salt environments of the fused materials require extensive sample purification for B ratio determination. The alternative wet-ashing sample decomposition with HF also results in B loss and isotopic fractionation owing to the high volatility of BF3. Open-vessel dry- or wet-ashing methods usually do not work well for animal samples, and are also prone to B loss and contamination. Closed-vessel microwave digestion overcomes these problems, but the digests of biological materials have high C contents, which cause spectral interference on 11B and affect 11B/10B ratios. Exchange separation/preconcentration of B using exchange (cation or anion exchange, B-specific resin, e.g., Amberlite IRA-743) tend to cause B isotope fractionation, and C eluting from these resin columns may interfere with B isotope ratio determination. Memory effects of B that occur during sample determination may cause serious errors in B isotope ratio determination, especially when samples varying in B concentrations and/or isotope composition are analyzed together. Although the utilization of high-resolution plasma-source MS will undoubtedly improve analytical precision, it is the sample preparation, sample introduction, and analytical methodology that represent the primary limitation to accurate and precise B isotope ratio determination.

  13. Fast isobaric separation at the collector of ISOL-facilities

    NASA Astrophysics Data System (ADS)

    Beyer, G. J.; Novgorodov, A. F.; Kovalev, A.; Prazak, F.; Khalkin, V. A.; Yushkevich, Yu. V.

    1981-07-01

    The release of radioactive isotopes of Rb, Sr, Y, Zr, Ba, several rare earth elements, Ra, Ac and Th after implantation at 45 keV into collector foils using the isotope separator of the JASNAPP-facility have been investigated. The heating of the collector foils inside a vacuum chamber up to defined temperatures caused a separation of the implanted elements. The separation-coefficients α for a 180 s heating period in an off-line mode are the following (Ta-backing was used in all cases except for αZr/Y in which case Zr-backing was used):

  14. Optimization in multidimensional gas chromatography applying quantitative analysis via a stable isotope dilution assay.

    PubMed

    Schmarr, Hans-Georg; Slabizki, Petra; Legrum, Charlotte

    2013-08-01

    Trace level analyses in complex matrices benefit from heart-cut multidimensional gas chromatographic (MDGC) separations and quantification via a stable isotope dilution assay. Minimization of the potential transfer of co-eluting matrix compounds from the first dimension ((1)D) separation into the second dimension separation requests narrow cut-windows. Knowledge about the nature of the isotope effect in the separation of labeled and unlabeled compounds allows choosing conditions resulting in at best a co-elution situation in the (1)D separation. Since the isotope effect strongly depends on the interactions of the analytes with the stationary phase, an appropriate separation column polarity is mandatory for an isotopic co-elution. With 3-alkyl-2-methoxypyrazines and an ionic liquid stationary phase as an example, optimization of the MDGC method is demonstrated and critical aspects of narrow cut-window definition are discussed.

  15. (Carbon isotope fractionation inplants)

    SciTech Connect

    O'Leary, M.H.

    1990-01-01

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.

  16. Kentucky Consumer & Homemaking Education. Food & Nutrition Curriculum Guide, Semester Course.

    ERIC Educational Resources Information Center

    Blankenship, Karen; And Others

    Intended for use by teachers at the high school level, this curriculum guide, which is one in a series of guides for consumer and homemaking education in Kentucky, outlines a semester special interest course in food management. The two units, comprehensive I and II, which are prerequisites for this course are found in a separate guide (CE 017…

  17. Isotopic composition of formaldehyde in urban air.

    PubMed

    Rice, Andrew L; Quay, Paul

    2009-12-01

    The isotopic composition of atmospheric formaldehyde was measured in air samples collected in urban Seattle, Washington. A recently developed gas chromatography-isotope ratio mass spectrometry analytical technique was used to extract formaldehyde directly from whole air, separate it from other volatile organic compounds, and measure its (13)C/(12)C and D/H ratio. Measurements of formaldehyde concentration were also made concomitant with isotope ratio. Results of the analysis of nine discrete air samples for delta(13)C-HCHO have a relatively small range in isotopic composition (-31 to -25 per thousand versus VPDB [+/-1.3 per thousand]) over a considerable concentration range (0.8-4.4 ppb [+/-15%]). In contrast, analyses of 17 air samples for deltaD-HCHO show a large range (-296 to +210 per thousand versus VSMOW [+/-50 per thousand]) over the concentrations measured (0.5-2.9 ppb). Observations of deltaD are weakly anticorrelated with concentration. Isotopic data are interpreted using both source- and sink-based approaches. Results of delta(13)C-HCHO are similar to those observed previously for a number of nonmethane hydrocarbons in urban environments and variability can be reconciled with a simple sink-based model. The large variability observed in deltaD-HCHO favors a source-based interpretation with HCHO depleted in deuterium from primary sources of HCHO (i.e., combustion) and HCHO enriched in deuterium from secondary photochemical sources (i.e., hydrocarbon oxidation).

  18. Highly tritiated water processing by isotopic exchange

    SciTech Connect

    Shu, W.M.; Willms, R.S.; Glugla, M.; Cristescu, I.; Michling, R.; Demange, D.

    2015-03-15

    Highly tritiated water (HTW) is produced in fusion machines and one of the promising technologies to process it is isotopic exchange. 3 kinds of Pt-catalyzed zeolite (13X-APG, CBV-100-CY and HiSiv-1000) were tested as candidates for isotopic exchange of highly tritiated water (HTW), and CBV-100-CY (Na-Y type with a SiO{sub 2}/Al{sub 2}O{sub 3} ratio of ∼ 5.0) shows the best performance. Small-scale tritium testing indicates that this method is efficient for reaching an exchange factor (EF) of 100. Full-scale non-tritium testing implies that an EF of 300 can be achieved in 24 hours of operation if a temperature gradient is applied along the column. For the isotopic exchange, deuterium recycled from the Isotope Separation System (deuterium with 1% T and/or 200 ppm T) should be employed, and the tritiated water regenerated from the Pt-catalyzed zeolite bed after isotopic exchange should be transferred to Water Detritiation System (WDS) for further processing.

  19. Stable isotope customer list and summary of shipments:

    SciTech Connect

    Tracy, J.G.

    1988-03-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: alphabetical lists of domestic and foreign customers;alphabetical lists of isotopes and services;alphabetical lists of states and countries;tabulation of the shipments, quantities, and dollars for each isotope and dollars for services divided into domestic, foreign, and DOE project categories. During FY 1987 sales of stable isotope products and services were made to 272 differnt customers, of whom 159 were domestic and 113 were foreign, representing 18 different foreign countries. The total revenue was $3,785,609 of which 12.3% was from sales to DOE project customers, 60.4% was from sales to other domestic customers, and 27.3% was from sales to foreign customers. this represented sales of 189 different stable isotopes plus associated services and was a 16.5% increase over FY 1986.

  20. Dual magnetic separator for TRIμP

    NASA Astrophysics Data System (ADS)

    Berg, G. P. A.; Dermois, O. C.; Dammalapati, U.; Dendooven, P.; Harakeh, M. N.; Jungmann, K.; Onderwater, C. J. G.; Rogachevskiy, A.; Sohani, M.; Traykov, E.; Willmann, L.; Wilschut, H. W.

    2006-05-01

    The TRIμP facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of 21Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested.

  1. Isotopic composition of lithium, potassium, rubidium, and strontium in lunar surface material

    NASA Technical Reports Server (NTRS)

    Zaslavskiy, V. G.; Levskiy, L. K.; Murin, A. N.

    1974-01-01

    The isotopic composition of alkali and alkaline earth elements in the Luna 16 regolith was investigated by the method of thermionic emission, without chemical separation. The isotopic composition of the lithium in two regolith samples did not differ (within the limits 0.5 percent) from the mean of the terrestrial reference standard. At the same time, the observed difference (1 percent) in the isotopic composition of lithium between the samples requires further investigation and confirmation. The isotopic compositions of K and Rb did not differ within the limits of experimental error from the isotopic composition of the reference standard.

  2. Stable-isotope customer list and summary of shipments, FY 1982

    SciTech Connect

    Davis, W.C.

    1983-04-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The inforamtion is divided into four sections: (1) alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; (2) alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; (3) alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and (4) tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope.

  3. Packed bed reactor for photochemical .sup.196 Hg isotope separation

    DOEpatents

    Grossman, Mark W.; Speer, Richard

    1992-01-01

    Straight tubes and randomly oriented pieces of tubing having been employed in a photochemical mercury enrichment reactor and have been found to improve the enrichment factor (E) and utilization (U) compared to a non-packed reactor. One preferred embodiment of this system uses a moving bed (via gravity) for random packing.

  4. TCAP HYDROGEN ISOTOPE SEPARATION USING PALLADIUM AND INVERSE COLUMNS

    SciTech Connect

    Heung, L.; Sessions, H.; Xiao, S.

    2010-08-31

    The Thermal Cycling Absorption Process (TCAP) was further studied with a new configuration. Previous configuration used a palladium packed column and a plug flow reverser (PFR). This new configuration uses an inverse column to replace the PFR. The goal was to further improve performance. Both configurations were experimentally tested. The results showed that the new configuration increased the throughput by a factor of more than 2.

  5. Analysis of Gas Membrane Ultra-High Purification of Small Quantities of Mono-Isotopic Silane

    SciTech Connect

    de Almeida, Valmor F.; Hart, Kevin J.

    2016-09-01

    A small quantity of high-value, crude, mono-isotopic silane is a prospective gas for a small-scale, high-recovery, ultra-high membrane purification process. This is an unusual application of gas membrane separation for which we provide a comprehensive analysis of a simple purification model. The goal is to develop direct analytic expressions for estimating the feasibility and efficiency of the method, and guide process design; this is only possible for binary mixtures of silane in the dilute limit which is a somewhat realistic case. Among the common impurities in crude silane, methane poses a special membrane separation challenge since it is chemically similar to silane. Other potential problematic surprises are: ethylene, diborane and ethane (in this order). Nevertheless, we demonstrate, theoretically, that a carefully designed membrane system may be able to purify mono-isotopic, crude silane to electronics-grade level in a reasonable amount of time and expenses. We advocate a combination of membrane materials that preferentially reject heavy impurities based on mobility selectivity, and light impurities based on solubility selectivity. We provide estimates for the purification of significant contaminants of interest. To improve the separation selectivity, it is advantageous to use a permeate chamber under vacuum, however this also requires greater control of in-leakage of impurities in the system. In this study, we suggest cellulose acetate and polydimethylsiloxane as examples of membrane materials on the basis of limited permeability data found in the open literature. We provide estimates on the membrane area needed and priming volume of the cell enclosure for fabrication purposes when using the suggested membrane materials. These estimates are largely theoretical in view of the absence of reliable experimental data for the permeability of silane. Last but not least, future extension of this work to the non-dilute limit may apply to the recovery of silane from

  6. ECORLOG computer application users' and programmers' guides

    SciTech Connect

    Winter, C.

    1984-09-01

    This document consists of two separate guides to the ECORLOG application. Sections One through Five make up the Users' Guide, while the Programmers' Guide is contained in the Appendix. The Programmers' Guide contains information that will be useful in maintaining or updating the ECORLOG application's capabilities, but is not needed for day-to-day use of the ECORLOG Job and programs. Each of the following four sections covers a separate aspect of ECORLOG. Section Two explains how data is entered into a Batch of the ECORLOG Job. In Section Three, several common data-editing operations are described. Instructions for running the three ECORLOG programs (ECORUP, ECRPT1 and ECRPT2) are given in Section Four, which also includes samples of the ECORLOG reports. Section Five concludes the Users' Guide with procedures for redirecting the output of ECORLOG reports to different printers, and for storing ECORLOG data at the end of a fiscal year.

  7. Shoulder separation - aftercare

    MedlinePlus

    Separated shoulder - aftercare; Acromioclavicular joint separation - aftercare; A/C separation - aftercare ... Most shoulder separation injuries are caused by falling onto the shoulder. This causes a tear in the tissue that connects the ...

  8. Carbon isotope ratios and isotopic correlations between components in fruit juices

    NASA Astrophysics Data System (ADS)

    Wierzchnicki, Ryszard

    2013-04-01

    Nowadays food products are defined by geographical origin, method of production and by some regulations concerning terms of their authenticity. Important data for confirm the authenticity of product are providing by isotopic methods of food control. The method checks crucial criteria which characterize the authenticity of inspected product. The European Union Regulations clearly show the tendency for application of the isotopic methods for food authenticity control (wine, honey, juice). The aim of the legislation steps is the protection of European market from possibility of the commercial frauds. Method of isotope ratio mass spectrometry is very effective tool for the use distinguishably the food products of various geographical origin. The basic problem for identification of the sample origin is the lack of databases of isotopic composition of components and information about the correlations of the data. The subject of the work was study the isotopic correlations existing between components of fruits. The chemical and instrumental methods of separation: water, sugars, organic acids and pulp from fruit were implemented. IRMS technique was used to measure isotopic composition of samples. The final results for original samples of fruits (apple, strawberry etc.) will be presented and discussed. Acknowledgement: This work was supported by the Polish Ministry of Science and Higher Education under grant NR12-0043-10/2010.

  9. Nitrogen isotopic signatures in agglutinates from breccia 79035

    NASA Technical Reports Server (NTRS)

    Kerridge, John F.; Kim, Yoosook; Kim, Jin S.; Marti, Kurt

    1993-01-01

    Agglutinates in the size range 125-175 microns from regolith breccia 79035 are substantially depleted in N compared with bulk 79035. Isotopically, agglutinate N closely resembles that found previously in ilmenite separates. The minimum (delta)N-15 value found during stepwise pyrolysis of agglutinates is significantly heavier than that observed for bulk 79035. The major host phase for trapped N in 79035, and the host phase of the lightest isotopic component(s), remain unidentified.

  10. Graphs for Isotopes of 107-Bh (Bohrium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 107-Bh (Bohrium, atomic number Z = 107).

  11. Graphs for Isotopes of 108-Hs (Hassium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 108-Hs (Hassium, atomic number Z = 108).

  12. Graphs for Isotopes of 97-Bk (Berkelium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 97-Bk (Berkelium, atomic number Z = 97).

  13. Graphs for Isotopes of 103-Lr (Lawrencium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 103-Lr (Lawrencium, atomic number Z = 103).

  14. Graphs for Isotopes of 106-Sg (Seaborgium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 106-Sg (Seaborgium, atomic number Z = 106).

  15. Graphs for Isotopes of 105-Db (Dubnium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 105-Db (Dubnium, atomic number Z = 105).

  16. Graphs for Isotopes of 91-Pa (Protactinium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 91-Pa (Protactinium, atomic number Z = 91).

  17. Microbial isotopic fractionation of perchlorate chlorine.

    PubMed

    Coleman, Max L; Ader, Magali; Chaudhuri, Swades; Coates, John D

    2003-08-01

    Perchlorate contamination can be microbially respired to innocuous chloride and thus can be treated effectively. However, monitoring a bioremediative strategy is often difficult due to the complexities of environmental samples. Here we demonstrate that microbial respiration of perchlorate results in a significant fractionation ( approximately -15 per thousand ) of the chlorine stable isotope composition of perchlorate. This can be used to quantify the extent of biotic degradation and to separate biotic from abiotic attenuation of this contaminant.

  18. Graphs for Isotopes of 89-Ac (Actinium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 89-Ac (Actinium, atomic number Z = 89).

  19. Graphs for Isotopes of 100-Fm (Fermium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 100-Fm (Fermium, atomic number Z = 100).

  20. Graphs for Isotopes of 109-Mt (Meitnerium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 109-Mt (Meitnerium, atomic number Z = 109).

  1. Graphs for Isotopes of 98-Cf (Californium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 98-Cf (Californium, atomic number Z = 98).

  2. Graphs for Isotopes of 101-Md (Mendelevium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides a graphic representation of nucleon separation energies and residual interaction parameters for isotopes of the chemical element 101-Md (Mendelevium, atomic number Z = 101).

  3. Developments towards in-gas-jet laser spectroscopy studies of actinium isotopes at LISOL

    NASA Astrophysics Data System (ADS)

    Raeder, S.; Bastin, B.; Block, M.; Creemers, P.; Delahaye, P.; Ferrer, R.; Fléchard, X.; Franchoo, S.; Ghys, L.; Gaffney, L. P.; Granados, C.; Heinke, R.; Hijazi, L.; Huyse, M.; Kron, T.; Kudryavtsev, Yu.; Laatiaoui, M.; Lecesne, N.; Luton, F.; Moore, I. D.; Martinez, Y.; Mogilevskiy, E.; Naubereit, P.; Piot, J.; Rothe, S.; Savajols, H.; Sels, S.; Sonnenschein, V.; Traykov, E.; Van Beveren, C.; Van den Bergh, P.; Van Duppen, P.; Wendt, K.; Zadvornaya, A.

    2016-06-01

    To study exotic nuclides at the borders of stability with laser ionization and spectroscopy techniques, highest efficiencies in combination with a high spectral resolution are required. These usually opposing requirements are reconciled by applying the in-gas-laser ionization and spectroscopy (IGLIS) technique in the supersonic gas jet produced by a de Laval nozzle installed at the exit of the stopping gas cell. Carrying out laser ionization in the low-temperature and low density supersonic gas jet eliminates pressure broadening, which will significantly improve the spectral resolution. This article presents the required modifications at the Leuven Isotope Separator On-Line (LISOL) facility that are needed for the first on-line studies of in-gas-jet laser spectroscopy. Different geometries for the gas outlet and extraction ion guides have been tested for their performance regarding the acceptance of laser ionized species as well as for their differential pumping capacities. The specifications and performance of the temporarily installed high repetition rate laser system, including a narrow bandwidth injection-locked Ti:sapphire laser, are discussed and first preliminary results on neutron-deficient actinium isotopes are presented indicating the high capability of this novel technique.

  4. Method for isotopic analysis of chlorinated organic compounds

    DOEpatents

    Holt, Ben D.; Sturchio, Neil C.

    1999-01-01

    The present invention provides a method for preparing a VOC sample for carbon and chlorine isotope ratio analysis by mass spectrometer. A VOC sample is placed in a combustion tube and reacted with CuO to form CO.sub.2 and CuCl. The CO.sub.2 is then extracted and analyzed for the carbon isotope ratio. The CuCl is separated from the excess CuO and reacted with CH.sub.3 I to form CH.sub.3 Cl, extracted and analyzed for chlorine isotope ratio.

  5. Method for isotopic analysis of chlorinated organic compounds

    DOEpatents

    Holt, B.D.; Sturchio, N.C.

    1999-08-24

    The present invention provides a method for preparing a VOC sample for carbon and chlorine isotope ratio analysis by mass spectrometer. A VOC sample is placed in a combustion tube and reacted with CuO to form CO{sub 2} and CuCl. The CO{sub 2} is then extracted and analyzed for the carbon isotope ratio. The CuCl is separated from the excess CuO and reacted with CH{sub 3}I to form CH{sub 3}Cl, extracted and analyzed for chlorine isotope ratio. 9 figs.

  6. Isotope and Nuclear Chemistry Division annual report, FY 1983

    SciTech Connect

    Heiken, J.H.; Lindberg, H.A.

    1984-05-01

    This report describes progress in the major research and development programs carried out in FY 1983 by the Isotope and Nuclear Chemistry Division. It covers radiochemical diagnostics of weapons tests; weapons radiochemical diagnostics research and development; other unclassified weapons research; stable and radioactive isotope production, separation, and applications (including biomedical applications); element and isotope transport and fixation; actinide and transition metal chemistry; structural chemistry, spectroscopy, and applications; nuclear structure and reactions; irradiation facilities; advanced analytical techniques; development and applications; atmospheric chemistry and transport; and earth and planetary processes.

  7. Isotopically controlled semiconductors

    SciTech Connect

    Haller, Eugene E.

    2006-06-19

    The following article is an edited transcript based on the Turnbull Lecture given by Eugene E. Haller at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his 'pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations'. The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin-film heterostructures. Isotopic composition affects several properties such as phonon energies, band structure, and lattice constant in subtle, but, for their physical understanding, significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photoluminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for simultaneous self- and dopant-diffusion studies. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.

  8. Site-Specific Carbon Isotopes in Organics

    NASA Astrophysics Data System (ADS)

    Piasecki, A.; Eiler, J. M.

    2012-12-01

    Natural organic molecules exhibit a wide range of internal site-specific isotope variation (i.e., molecules with same isotopic substitution type but different site). Such variations are generally unconstrained by bulk isotopic measurements. If known, site-specific variations might constrain temperatures of equilibrium, mechanisms of formation or consumption reactions, and possibly other details. For example, lipids can exhibit carbon isotope differences of up to 30‰ between adjacent carbon sites as a result of fractionations arising during decarboxylation of pyruvate and other steps in lipid biosynthesis(1). We present a method for site-specific carbon isotope analysis of propane, based on high-resolution, multi-collector gas source mass spectrometry, using a novel prototype instrument - the Thermo MAT 253 Ultra. This machine has an inlet system and electron bombardment ion source resembling those in conventional stable isotope gas source mass spectrometers, and the energy filter, magnet, and detector array resembling those in multi-collector ICPMS and TIMS. The detector array has 7 detector positions, 6 of which are movable, and each of which can collect ions with either a faraday cup (read through amplifiers ranging from 107-1012 ohms) or an SEM. High mass resolving power (up to 27,000, MRP = M/dM definition) is achieved through a narrow entrance slit, adjustable from 250 to 5 μm. Such resolution can cleanly separate isobaric interferences between isotopologues of organic molecules having the same cardinal mass (e.g., 13CH3 and 12CH2D). We use this technology to analyze the isotopologues and fragments of propane, and use such data to solve for the site-specific carbon isotope fractionation. By measuring isotopologues of both the one-carbon (13CH3) and the two-carbon (13C12CH4) fragment ion, we can solve for both bulk δ13C and the difference in δ13C between the terminal and central carbon position. We tested this method by analyzing mixtures between natural

  9. Radiochemical separation of gold by amalgam exchange

    USGS Publications Warehouse

    Ruch, R.R.

    1970-01-01

    A rapid and simple method for the radiochemical separation of gold after neutron activation. The technique is based on treatment with a dilute indium-gold amalgam, both chemical reduction and isotopic exchange being involved. The counting efficiency for 198Au in small volumes of the amalgam is good. Few interferences occur and the method is applicable to clays, rocks, salts and metals. The possibility of determining silver, platinum and palladium by a similar method is mentioned. ?? 1970.

  10. Tracing origins of cratonic eclogites by magnesium isotopes

    NASA Astrophysics Data System (ADS)

    Wang, S.; Teng, F. Z.; Rudnick, R. L.; Li, S. G.

    2014-12-01

    Cratonic eclogites are samples of lithospheric mantle preserved beneath ancient continental cratons. Hence, the origin of cratonic eclogites is closely related to the formation and evolution of cratonic mantle. Here we report Mg isotopic compositions for 27 cratonic eclogites and 52 garnet and clinopyroxene mineral separates from Koidu, Bellsbank and Kaalvallei kimberlite pipes in South and West Africa. Whole-rock Mg isotopic compositions vary widely, with δ26Mg ranging from -1.60 to +0.17, significantly different from the value (δ26Mg = -0.25 ± 0.07) of peridotite xenoliths. Garnet and clinopyroxene in these cratonic eclogites record equilibrium inter-mineral Mg isotope partitioning at mantle temperatures, with Δ26MgCpx-Grt (= δ26MgCpx - δ26MgGrt) in the range of 0.43 - 0.85 ‰. The constructed bulk δ26Mg values based on mineral compositions are identical to the measured whole-rock values, indicating limited influence of kimberlite infiltration on Mg isotopic compositions of cratonic eclogites. As significant Mg isotope fractionation can only occur during low-temperature surface processes, the large Mg isotopic variations of cratonic eclogites suggest the incorporation of subducted materials in their protoliths. Therefore, our Mg isotopic data suggest the cratonic eclogites are the remnants of subducted oceanic crust within the lithospheric mantle. Collectively, Mg isotopes are potentially excellent tracers of the formation and evolution of sub-continental lithospheric mantle.

  11. Ferrofluid separator for nonferrous scrap separation

    NASA Technical Reports Server (NTRS)

    Kaiser, R.; Mir, L.

    1974-01-01

    Behavior of nonmagnetic objects within separator is essentially function of density, and independent of size or shape of objects. Results show close agreement between density of object and apparent density of ferrofluid required to float it. Results also demonstrate that very high separation rates are achievable by ferrofluid sink-float separation.

  12. Perchlorate isotope forensics

    USGS Publications Warehouse

    Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Horita, J.; Brown, G.M.; Jackson, W.A.; Batista, J.; Hatzinger, P.B.

    2005-01-01

    Perchlorate has been detected recently in a variety of soils, waters, plants, and food products at levels that may be detrimental to human health. These discoveries have generated considerable interest in perchlorate source identification. In this study, comprehensive stable isotope analyses ( 37Cl/35Cl and 18O/17O/ 16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. In addition, isotopic analyses of perchlorate extracted from groundwater and surface water demonstrate the feasibility of identifying perchlorate sources in contaminated environments on the basis of this technique. Both natural and synthetic sources of perchlorate have been identified in water samples from some perchlorate occurrences in the United States by the isotopic method. ?? 2005 American Chemical Society.

  13. Isotopically controlled semiconductors

    SciTech Connect

    Haller, E.E.

    2004-11-15

    A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.

  14. Stable isotopes in mineralogy

    USGS Publications Warehouse

    O'Neil, J.R.

    1977-01-01

    Stable isotope fractionations between minerals are functions of the fundamental vibrational frequencies of the minerals and therefore bear on several topics of mineralogical interest. Isotopic compositions of the elements H, C, O, Si, and S can now be determined routinely in almost any mineral. A summary has been made of both published and new results of laboratory investigations, analyses of natural materials, and theoretical considerations which bear on the importance of temperature, pressure, chemical composition and crystal structure to the isotopic properties of minerals. It is shown that stable isotope studies can sometimes provide evidence for elucidating details of crystal structure and can be a powerful tool for use in tracing the reaction paths of mineralogical reactions. ?? 1977 Springer-Verlag.

  15. Deciphering Ecohydrological Interactions Using Stable Isotopes

    NASA Astrophysics Data System (ADS)

    McDonnell, J.; Evaristo, J. A.; Jasechko, S.

    2014-12-01

    Deciphering the nature of ecohydrological interconnections and scaling that knowledge gained at single points to watersheds is challenging. One tool that that has proved useful in this regard is stable isotope tracing. Single isotope studies have been used recently to quantify landuse change effects on streamflow source apportionment and ecological effects on transit time distributions of water at the catchment scale. However, most work to date has assumed that plant transpiration, groundwater recharge and streamflow are all sourced or mediated by the same well mixed reservoir—the soil. Recent work in Oregon and Mexico has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater recharge and streamflow. However, these findings have not yet been widely tested. Here we assemble the first dual isotope database for δ2H and δ18O extracted from 47 globally-distributed stable isotopic datasets. We use these data to test the ecohydrological separation hypothesis. We combine this dual isotope dataset with global precipitation, streamwater, groundwater and soil water datasets. Our results show that precipitation, streamwater and groundwater from the 47 sites plot approximately along the δ2H/δ18O slope of eight, suggesting that local precipitation inputs supply streamwater and groundwater. Soil waters extracted from the 47 studies plot below the regression of local streamwater and groundwater with a slope of 6.6±0.05 ‰. Local plant xylem waters from our matched dataset plot on a slope 6.6±0.07 ‰ consistent with local soil waters. The tight association of soil water slopes and not that of local groundwater or streamflow suggests that plants use soil water that does not itself contribute to groundwater recharge or stream water. This ubiquity of subsurface water compartmentalization is surprising and has important implications for how we

  16. Isotope production and distribution Programs Fiscal Year (FY) 1995 Financial Statement Audit (ER-FC-96-01)

    SciTech Connect

    1996-02-12

    The charter of the Department of Energy (DOE) Isotope Production and Distribution Program (Isotope Program) covers the production and sale of radioactive and stable isotopes, associated byproducts, surplus materials such as lithium and deuterium, and related isotope services. Services provided include, but are not limited to, irradiation services, target preparation and processing, source encapsulation and other special preparations, analyses, chemical separations, and leasing of stable isotopes for research purposes. Isotope Program products and services are sold worldwide for use in a wide variety of research, development, biomedical, and industrial applications. The Isotope Program reports to the Director of the Office of Nuclear Energy, Science and Technology. The Isotope Program operates under a revolving fund, as established by the Fiscal Year 1990 Energy and Water Appropriations Act (Public Law 101-101). The Fiscal Year 1995 Appropriations Act (Public Law 103-316) modified predecessor acts to allow prices charged for Isotope Program products and services to be based on production costs, market value, the needs of the research community, and other factors. Prices set for small-volume, high-cost isotopes that are needed for research may not achieve full-cost recovery. Isotope Program costs are financed by revenues from the sale of isotopes and associated services and through payments from the isotope support decision unit, which was established in the DOE fiscal year 1995 Energy, Supply, Research, and Development appropriation. The isotope decision unit finances the production and processing of unprofitable isotopes that are vital to the national interest.

  17. Titan's Isotopic Menagerie: The Cassini CIRS Perspective

    NASA Astrophysics Data System (ADS)

    Nixon, Conor A.; Achterberg, R. K.; Bezard, B.; Bjoraker, G. L.; Coustenis, A.; de Kok, R.; Flasar, F. M.; Hewagama, T.; Irwin, P. G. J.; Jennings, D. E.; Jolly, A.; Romani, P. N.; Teanby, N. A.; Vinatier, S.; CIRS Team

    2008-09-01

    Saturn's long-mysterious moon Titan is gradually yielding up its secrets under the intense scrutiny of the Cassini spacecraft, which has just completed a 4-year prime mission including 45 close flybys of the giant satellite. We here focus on the isotopic composition of the stratosphere, which since Voyager 1 in 1980 has been known to comprise a surprisingly rich mixture of hydrocarbons, nitriles and several oxygen species. These molecules are now understood to originate in the upper atmosphere by chemical processes initiated by the dissociation of the most abundant native species - methane and nitrogen - with some oxygen added from externally-supplied water. Measurements of isotopic ratios in these compounds are important and can provide valuable information on the formation and evolution of Titan's atmosphere. E.g. Chemical processes can cause isotopic fractionation via the 'kinetic isotope effect' (KIE). Cassini's Composite Infrared Spectrometer (CIRS), which is sensitive to thermal infrared radiation from 10-1500 cm-1 (7-1000 micron), is an ideal tool for measuring molecular concentrations and can distinguish between isotopologues due to the shifts in the molecular bands. CIRS has now identified at least eleven isotopologue species in our spectra, with multiple new detections in the past year (13CO2, CO18O, HC13CCCN). CIRS has measured the ratios 12C/13C in a total of seven species, D/H in two species, and 14N/15N and 16O/18O each in one species - the best measurement so far of the important ratio 16O/18O on Titan (346±110). In this presentation we will summarize all our results to date on isotopic ratios, including comparison with Huygens GCMS and other determinations, a discussion of possible isotopic separation in hydrocarbon chains, and formation/evolution implications of these measurements for Titan.

  18. Fertilizer nitrogen isotope signatures.

    PubMed

    Bateman, Alison S; Kelly, Simon D

    2007-09-01

    There has been considerable recent interest in the potential application of nitrogen isotope analysis in discriminating between organically and conventionally grown crops. A prerequisite of this approach is that there is a difference in the nitrogen isotope compositions of the fertilizers used in organic and conventional agriculture. We report new measurements of delta15N values for synthetic nitrogen fertilizers and present a compilation of the new data with existing literature nitrogen isotope data. Nitrogen isotope values for fertilizers that may be permitted in organic cultivation systems are also reported (manures, composts, bloodmeal, bonemeal, hoof and horn, fishmeal and seaweed based fertilizers). The delta15N values of the synthetic fertilizers in the compiled dataset fall within a narrow range close to 0 per thousand with 80% of samples lying between-2 and 2 per thousand and 98.5% of the data having delta15N values of less than 4 per thousand (mean=0.2 per thousand n=153). The fertilizers that may be permitted in organic systems have a higher mean delta15N value of 8.5 per thousand and exhibit a broader range in delta15N values from 0.6 to 36.7 per thousand (n=83). The possible application of the nitrogen isotope approach in discriminating between organically and conventionally grown crops is discussed in light of the fertilizer data presented here and with regard to other factors that are also important in determining crop nitrogen isotope values.

  19. Osmium isotopes and mantle convection.

    PubMed

    Hauri, Erik H

    2002-11-15

    The decay of (187)Re to (187)Os (with a half-life of 42 billion years) provides a unique isotopic fingerprint for tracing the evolution of crustal materials and mantle residues in the convecting mantle. Ancient subcontinental mantle lithosphere has uniquely low Re/Os and (187)Os/(188)Os ratios due to large-degree melt extraction, recording ancient melt-depletion events as old as 3.2 billion years. Partial melts have Re/Os ratios that are orders of magnitude higher than their sources, and the subduction of oceanic or continental crust introduces into the mantle materials that rapidly accumulate radiogenic (187)Os. Eclogites from the subcontinental lithosphere have extremely high (187)Os/(188)Os ratios, and record ages as old as the oldest peridotites. The data show a near-perfect partitioning of Re/Os and (187)Os/(188)Os ratios between peridotites (low) and eclogites (high). The convecting mantle retains a degree of Os-isotopic heterogeneity similar to the lithospheric mantle, although its amplitude is modulated by convective mixing. Abyssal peridotites from the ocean ridges have low Os isotope ratios, indicating that the upper mantle had undergone episodes of melt depletion prior to the most recent melting events to produce mid-ocean-ridge basalt. The amount of rhenium estimated to be depleted from the upper mantle is 10 times greater than the rhenium budget of the continental crust, requiring a separate reservoir to close the mass balance. A reservoir consisting of 5-10% of the mantle with a rhenium concentration similar to mid-ocean-ridge basalt would balance the rhenium depletion of the upper mantle. This reservoir most likely consists of mafic oceanic crust recycled into the mantle over Earth's history and provides the material that melts at oceanic hotspots to produce ocean-island basalts (OIBs). The ubiquity of high Os isotope ratios in OIB, coupled with other geochemical tracers, indicates that the mantle sources of hotspots contain significant quantities

  20. Isotopes in geobiochemistry: tracing metabolic pathways in microorganisms of environmental relevance with stable isotopes.

    PubMed

    Adrian, Lorenz; Marco-Urrea, Ernest

    2016-10-01

    Stable isotopes are flexibly used as tracers to investigate environmental processes, microorganisms responsible for environmental transformations, syntrophic relationships in consortia, and metabolic pathways. With the advent of widely accessible high-resolution, highly accurate and sensitive mass spectrometers connected to liquid chromatography (LC-MS/MS) and the explosion of microbial genome sequence information the options to apply stable isotope tracers to geobiochemical topics have multiplied. With methods at hand to analyze biochemical pathways and enzymatic functions of yet-uncultivated microorganisms even in mixed cultures, a wide field of new discoveries can be expected. Applications rely both on the high sensitivity to detect trace amounts of biological material in slow or non-growing cultures and on the high multi-dimensional resolution of LC-MS/MS to allow the separation of complex samples and to retrieve phylogenetic information. Challenges and examples of stable isotope applications to describe geobiochemical processes are reviewed. Overall, the potential is not yet sufficiently deployed.

  1. Isotopic signatures by bulk analyses

    SciTech Connect

    Efurd, D.W.; Rokop, D.J.

    1997-12-01

    Los Alamos National Laboratory has developed a series of measurement techniques for identification of nuclear signatures by analyzing bulk samples. Two specific applications for isotopic fingerprinting to identify the origin of anthropogenic radioactivity in bulk samples are presented. The first example is the analyses of environmental samples collected in the US Arctic to determine the impact of dumping of radionuclides in this polar region. Analyses of sediment and biota samples indicate that for the areas sampled the anthropogenic radionuclide content of sediments was predominantly the result of the deposition of global fallout. The anthropogenic radionuclide concentrations in fish, birds and mammals were very low. It can be surmised that marine food chains are presently not significantly affected. The second example is isotopic fingerprinting of water and sediment samples from the Rocky Flats Facility (RFP). The largest source of anthropogenic radioactivity presently affecting surface-waters at RFP is the sediments that are currently residing in the holding ponds. One gram of sediment from a holding pond contains approximately 50 times more plutonium than 1 liter of water from the pond. Essentially 100% of the uranium in Ponds A-1 and A-2 originated as depleted uranium. The largest source of radioactivity in the terminal Ponds A-4, B-5 and C-2 was naturally occurring uranium and its decay product radium. The uranium concentrations in the waters collected from the terminal ponds contained 0.05% or less of the interim standard calculated derived concentration guide for uranium in waters available to the public. All of the radioactivity observed in soil, sediment and water samples collected at RFP was naturally occurring, the result of processes at RFP or the result of global fallout. No extraneous anthropogenic alpha, beta or gamma activities were detected. The plutonium concentrations in Pond C-2 appear to vary seasonally.

  2. Laser Ablation Molecular Isotopic Spectrometry: Strontium and its isotopes

    NASA Astrophysics Data System (ADS)

    Mao, Xianglei; Bol'shakov, Alexander A.; Choi, Inhee; McKay, Christopher P.; Perry, Dale L.; Sorkhabi, Osman; Russo, Richard E.

    2011-11-01

    The experimental details are reported of Laser Ablation Molecular Isotopic Spectrometry (LAMIS) and its application for performing optical isotopic analysis of solid strontium-containing samples in ambient atmospheric air at normal pressure. The LAMIS detection method is described for strontium isotopes from samples of various chemical and isotopic compositions. The results demonstrate spectrally resolved measurements of the three individual 86Sr, 87Sr, and 88Sr isotopes that are quantified using multivariate calibration of spectra. The observed isotopic shifts are consistent with those calculated theoretically. The measured spectra of diatomic oxide and halides of strontium generated in laser ablation plasmas demonstrate the isotopic resolution and capability of LAMIS. In particular, emission spectra of SrO and SrF molecular radicals provided clean and well resolved spectral signatures for the naturally occurring strontium isotopes. A possibility is discussed of using LAMIS of strontium isotopes for radiogenic age determination.

  3. Endemic Mo Isotopic Anomalies in Iron and Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Chen, J. H.; Papanastassiou, D. A.; Wasserburg, G. J.; Ngo, H. H.

    2004-01-01

    Mo in refractory interstellar grains shows large isotope anomalies. Recent Mo studies showed isotope effects in Allende and Murchison, and in iron meteorites, mesosiderites, and pallasites. Excesses of p- and r-process isotopes (or depletion of sprocess isotopes) of up to 3.5 epsilon units (epsilon u=parts in 10(exp 4)) were reported. We have reported on endemic isotope anomalies in Ru. Other workers have resolved no isotope anomalies for Mo or Ru and have claimed that the work by others is incorrect. Because Ru isotopes can interfere at Mo-96, Mo-98, Mo-100, we improved the chemical separations and eliminated interferences. For Mo work, we used the same solutions from which we separated and analyzed Ru. Three of the iron meteorites (Coahuila, Cape York, and Cape of Good Hope) were chosen for their large Mo isotopic effects. Mo was loaded on outgassed Re filaments, and then reduced; we used Ba(OH)2-NaOH as emitter, and measured Mo in static mode, as MoO3(-). We used Mo-98/Mo-96 for the mass fractionation correction (exponential law). No interferences from Ru or Zr isotopes were detected using the electron multiplier and no corrections were needed. For results on Mo standards we show 2 sigma(not 2 sigma mean) external precision better than: 0.7 epsilon u for Mo-94/Mo-96 and Mo-95/Mo-96; 1.0 epsilon u for Mo-92/Mo-96 and Mo-97/Mo-96; 1.4 epsilon u for Mo-100/Mo-96. Reproducibility for Mo standards is shown as contours (blue lines).

  4. Experimental systems overview of the Rare Isotope Science Project in Korea

    NASA Astrophysics Data System (ADS)

    Tshoo, K.; Kim, Y. K.; Kwon, Y. K.; Woo, H. J.; Kim, G. D.; Kim, Y. J.; Kang, B. H.; Park, S. J.; Park, Y.-H.; Yoon, J. W.; Kim, J. C.; Lee, J. H.; Seo, C. S.; Hwang, W.; Yun, C. C.; Jeon, D.; Kim, S. K.

    2013-12-01

    The Rare Isotope Science Project (RISP) was launched by the Institute for Basic Science (IBS) in December 2011 in Korea. The project aims to construct the new accelerator complex consisting of the Isotope Separation On-Line (ISOL) and the In-Flight Fragment (IF) facilities for the rare isotope science. The scientific programs and the experimental systems of RISP are briefly introduced with an overview of the complex.

  5. Oxygen Isotopes in Meteorites

    NASA Astrophysics Data System (ADS)

    Clayton, R. N.

    2003-12-01

    Oxygen isotope abundance variations in meteorites are very useful in elucidating chemical and physical processes that occurred during the formation of the solar system (Clayton, 1993). On Earth, the mean abundances of the three stable isotopes are 16O: 99.76%, 17O: 0.039%, and 18O: 0.202%. It is conventional to express variations in abundances of the isotopes in terms of isotopic ratios, relative to an arbitrary standard, called SMOW (for standard mean ocean water), as follows:The isotopic composition of any sample can then be represented by one point on a "three-isotope plot," a graph of δ17O versus δ18O. It will be seen that such plots are invaluable in interpreting meteoritic data. Figure 1 shows schematically the effect of various processes on an initial composition at the center of the diagram. Almost all terrestrial materials lie along a "fractionation" trend; most meteoritic materials lie near a line of "16O addition" (or subtraction). (4K)Figure 1. Schematic representation of various isotopic processes shown on an oxygen three-isotope plot. Almost all terrestrial materials plot along a line of "fractionation"; most primitive meteoritic materials plot near a line of "16O addition." The three isotopes of oxygen are produced by nucleosynthesis in stars, but by different nuclear processes in different stellar environments. The principal isotope, 16O, is a primary isotope (capable of being produced from hydrogen and helium alone), formed in massive stars (>10 solar masses), and ejected by supernova explosions. The two rare isotopes are secondary nuclei (produced in stars from nuclei formed in an earlier generation of stars), with 17O coming primarily from low- and intermediate-mass stars (<8 solar masses), and 18O coming primarily from high-mass stars (Prantzos et al., 1996). These differences in type of stellar source result in large observable variations in stellar isotopic abundances as functions of age, size, metallicity, and galactic location ( Prantzos

  6. Separation Anxiety (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Separation Anxiety KidsHealth > For Parents > Separation Anxiety Print A ... help both of you get through it. About Separation Anxiety Babies adapt pretty well to other caregivers. ...

  7. Physicochemical isotope anomalies

    SciTech Connect

    Esat, T.M.

    1988-06-01

    Isotopic composition of refractory elements can be modified, by physical processes such as distillation and sputtering, in unexpected patterns. Distillation enriches the heavy isotopes in the residue and the light isotopes in the vapor. However, current models appear to be inadequate to describe the detailed mass dependence, in particular for large fractionations. Coarse- and fine-grained inclusions from the Allende meteorite exhibit correlated isotope effects in Mg both as mass-dependent fractionation and residual anomalies. This isotope pattern can be duplicated by high temperature distillation in the laboratory. A ubiquitous property of meteoritic inclusions for Mg as well as for most of the other elements, where measurements exist, is mass-dependent fractionation. In contrast, terrestrial materials such as microtektites, tektite buttons as well as lunar orange and green glass spheres have normal Mg isotopic composition. A subset of interplanetary dust particles labelled as chondritic aggregates exhibit excesses in {sup 26}Mg and deuterium anomalies. Sputtering is expected to be a dominant mechanism in the destruction of grains within interstellar dust clouds. An active proto-sun as well as the present solar-wind and solar-flare flux are of sufficient intensity to sputter significant amounts of material. Laboratory experiments in Mg show widespread isotope effects including residual {sup 26}Mg excesses and mass dependent fractionation. It is possible that the {sup 26}Mg excesses in interplanetary dust is related to sputtering by energetic solar-wind particles. The implication if the laboratory distillation and sputtering effects are discussed and contrasted with the anomalies in meteoritic inclusions the other extraterrestrial materials the authors have access to.

  8. Stable carbon isotope analysis of coprocessing materials

    SciTech Connect

    Burke, F.P.; Winschel, R.A.; Lancet, M.S.

    1989-06-01

    The program is designed to address a substantial, demonstrated need of the coprocessing community (both exploratory and development) for a technique to quantitatively distinguish the contributions of the individual coprocessing feedstocks to the various products. The carbon isotope technique is currently in routine use for other applications. Results achieved this quarter include: Feed and product fractions from a Kentucky 9 coal/Kentucky tar sand bitumen coprocessing bench unit run at the Kentucky Center for Applied Energy Research (CAER) were analyzed for carbon isotope ratios. Corrections were made to the coal carbon recoveries and selectivities from the products of HRI Run 227-53. Feeds (Westerholt coal/Cold Lake VSB) and products from two periods of HRI coprocessing Run 238-1 were analyzed. Three petroleum samples and three coal samples were pyrolyzed at 800{degree}F for 30 min to determine the effect of pyrolysis on the isotopic homogeneity of each petroleum and coal sample. Products from each pyrolysis test were separated into five fractions; an additional set of coprocessing samples and a set of two-stage coal liquefaction samples were obtained from HRI for future work; work performed by the Pennsylvania State University show that microscopy is a promising method for distinguishing coal and petroleum products in residual coprocessing materials; and coal and petroleums that have large differences in carbon isotope ratios were identified for Auburn University. 7 refs., 2 figs., 12 tabs.

  9. Spacecraft -- Capsule Separation (Animation)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Spacecraft -- Capsule Separation animation

    This animation shows the return capsule separating from the Stardust spacecraft.

  10. Heavy element stable isotope ratios: analytical approaches and applications.

    PubMed

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-03-01

    Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

  11. Analysis of gas membrane ultra-high purification of small quantities of mono-isotopic silane

    DOE PAGES

    de Almeida, Valmor F.; Hart, Kevin J.

    2017-01-03

    A small quantity of high-value, crude, mono-isotopic silane is a prospective gas for a small-scale, high-recovery, ultra-high membrane purification process. This is an unusual application of gas membrane separation for which we provide a comprehensive analysis of a simple purification model. The goal is to develop direct analytic expressions for estimating the feasibility and efficiency of the method, and guide process design; this is only possible for binary mixtures of silane in the dilute limit which is a somewhat realistic case. In addition, analytic solutions are invaluable to verify numerical solutions obtained from computer-aided methods. Hence, in this paper wemore » provide new analytic solutions for the purification loops proposed. Among the common impurities in crude silane, methane poses a special membrane separation challenge since it is chemically similar to silane. Other potential problematic compounds are: ethylene, diborane and ethane (in this order). Nevertheless, we demonstrate, theoretically, that a carefully designed membrane system may be able to purify mono-isotopic, crude silane to electronics-grade level in a reasonable amount of time and expenses. We advocate a combination of membrane materials that preferentially reject heavy impurities based on mobility selectivity, and light impurities based on solubility selectivity. We provide estimates for the purification of significant contaminants of interest. In this study, we suggest cellulose acetate and polydimethylsiloxane as examples of membrane materials on the basis of limited permeability data found in the open literature. We provide estimates on the membrane area needed and priming volume of the cell enclosure for fabrication purposes when using the suggested membrane materials. These estimates are largely theoretical in view of the absence of reliable experimental data for the permeability of silane. And finally, future extension of this work to the non-dilute limit may apply to the

  12. Transportation of medical isotopes

    SciTech Connect

    Nielsen, D.L.

    1997-11-19

    A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

  13. Hydrocyclone separation system

    SciTech Connect

    Worrell, J.R.; Wakley, W.D.; Young, G.A.

    1990-05-22

    This patent describes a hydrocyclone separation system for separating a fluid mixture into at least two components having differing densities. It comprises: a first hydrocyclone separator and a second hydrocyclone separator contained within an elongated protective conduit and each being substantially parallel to a longitudinal axis of the conduit, each hydrocyclone separator having a tangential fluid inlet, an overflow fluid outlet and an underflow fluid outlet; and the first hydrocyclone separator and the second hydrocyclone separator being oppositely disposed with respect to each other with the underflow fluid outlet of the first hydrocyclone separator being spaced immediately adjacent to the tangential fluid inlet of the second hydrocyclone separator and the overflow fluid outlet of the first hydrocyclone separator being spaced immediately adjacent the underflow fluid outlet of the second hydrocyclone separator.

  14. Isotope geochemistry. Biological signatures in clumped isotopes of O₂.

    PubMed

    Yeung, Laurence Y; Ash, Jeanine L; Young, Edward D

    2015-04-24

    The abundances of molecules containing more than one rare isotope have been applied broadly to determine formation temperatures of natural materials. These applications of "clumped" isotopes rely on the assumption that isotope-exchange equilibrium is reached, or at least approached, during the formation of those materials. In a closed-system terrarium experiment, we demonstrate that biological oxygen (O2) cycling drives the clumped-isotope composition of O2 away from isotopic equilibrium. Our model of the system suggests that unique biological signatures are present in clumped isotopes of O2—and not formation temperatures. Photosynthetic O2 is depleted in (18)O(18)O and (17)O(18)O relative to a stochastic distribution of isotopes, unlike at equilibrium, where heavy-isotope pairs are enriched. Similar signatures may be widespread in nature, offering new tracers of biological and geochemical cycling.

  15. U-Pb isotopic systematics of ferroan anorthosite 60025

    NASA Technical Reports Server (NTRS)

    Premo, W. R.; Tatsumoto, M.

    1993-01-01

    Preliminary U-Pb isotopic data from separates of ferroan anorthosite 60025 confirm its antiquity at approximately 4.42 Ga. Three Pb-Pb isochron ages involving different sets of mineral separates vary by only 20 million years, but indicate derivation of the sets from isotopically distinct magma sources. If this anorthosite was a monomict cumulate product formed during the Moon's early primary differentiation stage, then residual liquids of crystallizing magmas were evolving isotopically, even at the cm-scale, over the duration of the crystallization period. Another explanation is that this sample is simply a polymict breccia and that the Pb isotopic results are a result of subsequent mechanical mixing of mineral assemblages from various cumulate piles formed coevally at approximately 4.42 Ga from isotopically distinct magma sources. In our ongoing search for early lunar Pb isotopic compositions, we have analyzed Apollo 16 anorthosites 67075 and 62337 and Apollo 17 high-Mg suite cumulates (troctolite 76535, norite 78235, and dunite 72415). The U-Pb isotopic systematics have been better behaved in the high-Mg suite rocks than in the anorthosites that have shown evidence of mineral assemblages of mixed parentage. Our aim in analyzing anorthosite 60025 was to avoid or minimize this problem as it had been considered essentially monomict, although recent work has shown that not only is 60025 polymict, but shows textual evidence of at least two episodes of deformation. Of five splits studied by James, Lindstrom and McGee, the four mineral splits appeared monomict, whereas the whole-rock split was considered polymict. Previous isotopic work indicate that this anorthosite was quite primitive, a claim that was apparently confirmed by the U-Pb isotopic age of 4.51 +/- .01 Ga on three plagioclase separates. However, a Sm-Nd internal isochron age of 4.44 +/- 0.02 Ga was determined using plagioclase, olivine, and mafic mineral separates, creating some doubt about the anorthosite

  16. Selection of Isotopes and Elements for Fuel Cycle Analysis

    SciTech Connect

    Steven J. Piet

    2009-04-01

    Fuel cycle system analysis simulations examine how the selection among fuel cycle options for reactors, fuel, separation, and waste management impact uranium ore utilization, waste masses and volumes, radiotoxicity, heat to geologic repositories, isotope-dependent proliferation resistance measures, and so forth. Previously, such simulations have tended to track only a few actinide and fission product isotopes, those that have been identified as important to a few criteria from the standpoint of recycled material or waste, taken as a whole. After accounting for such isotopes, the residual mass is often characterized as “fission product other” or “actinide other”. However, detailed assessment of separation and waste management options now require identification of key isotopes and residual mass for Group 1A/2A elements (Rb, Cs, Sr, Ba), inert gases (Kr, Xe), halogens (Br, I), lanthanides, transition metals, transuranic (TRU), uranium, actinide decay products. The paper explains the rationale for a list of 81 isotopes and chemical elements to better support separation and waste management assessment in dynamic system analysis models such as Verifiable Fuel Cycle Simulation (VISION)

  17. System for recovery of daughter isotopes from a source material

    SciTech Connect

    Tranter, Troy J; Todd, Terry A; Lewis, Leroy C; Henscheid, Joseph P

    2009-08-04

    A method of separating isotopes from a mixture containing at least two isotopes in a solution is disclosed. A first isotope is precipitated and is collected from the solution. A daughter isotope is generated and collected from the first isotope. The invention includes a method of producing an actinium-225/bismuth-213 product from a material containing thorium-229 and thorium-232. A solution is formed containing nitric acid and the material containing thorium-229 and thorium-232, and iodate is added to form a thorium iodate precipitate. A supernatant is separated from the thorium iodate precipitate and a second volume of nitric acid is added to the thorium iodate precipitate. The thorium iodate precipitate is stored and a decay product comprising actinium-225 and bismuth-213 is generated in the second volume of nitric acid, which is then separated from the thorium iodate precipitate, filtered, and treated using at least one chromatographic procedure. A system for producing an actinium-225/bismuth-213 product is also disclosed.

  18. Laser fluorescence spectroscopy on fast ion beams at the Marburg separator

    NASA Astrophysics Data System (ADS)

    Wagner, H.; Dörschel, K.; Höhle, C.; Hühnermann, H.; Meier, Th.

    Optical hyperfine structure and isotope shift measurements have been performed on Xe +, Ba + and La +-ions using an electromagnetic mass separator for the preselection of the isotopes by fast ion beam laser spectroscopy. The different measuring techniques used are described and their precision and sensitivity are discussed.

  19. Hydrogen isotope type-curves of very hot crude oils.

    PubMed

    Fekete, József; Sajgó, Csanád; Demény, Attila

    2011-01-15

    Several crude oil accumulations in the Pannonian Basin are trapped in uncommonly hot (>170°C) reservoirs. Their maturities range from mature to very mature on the basis of cracking parameters of their biological marker homologous series (ratio of products to reactants). A stable carbon isotopic study of these oils, poor in biological markers commonly used for correlation purposes, did not provide a reliable oil-to-oil correlation. As an alternative tool, the hydrogen isotope compositions of oil fractions separated on the basis of different polarities were measured, and hydrogen isotope type-curves were generated for a set of mature to very mature crude oil samples. This method of presenting hydrogen isotope composition of fractions as type-curves is novel. Nineteen samples (17 crude oils from SE-Hungary, 1 oil condensate and 1 artificial oil) were chosen for the present study. The aim was to examine the applicability of hydrogen isotope type-curves in oil-to-oil correlation and to test the simultaneous application of carbon and hydrogen isotope type-curves in the field of petroleum geochemistry. We have shown that, although the conventionally used co-variation plots proved to be inadequate for the correlation of these hot and mature oils, the simultaneous use of carbon and the newly introduced hydrogen isotope type-curves allows us to group and distinguish oils of different origins.

  20. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    PubMed Central

    Wallner, A.; Melber, K.; Merchel, S.; Ott, U.; Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.

    2013-01-01

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of 198Pt/195Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction. PMID:23565017

  1. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    NASA Astrophysics Data System (ADS)

    Wallner, A.; Melber, K.; Merchel, S.; Ott, U.; Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.

    2013-01-01

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of 198Pt/195Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.

  2. Protective Action Guides (PAGs)

    EPA Pesticide Factsheets

    The Protective Action Guide (PAG) manual contains radiation dose guidelines that would trigger public safety measures. EPA developed Protective Action Guides to help responders plan for radiation emergencies.

  3. COATING ALTERNATIVES GUIDE (CAGE) USER'S GUIDE

    EPA Science Inventory

    The guide provides instructions for using the Coating Alternatives GuidE (CAGE) software program, version 1.0. It assumes that the user is familiar with the fundamentals of operating an IBM-compatible personal computer (PC) under the Microsoft disk operating system (MS-DOS). CAGE...

  4. (n,{gamma}) Experiments on tin isotopes

    SciTech Connect

    Baramsai, B.; Mitchell, G. E.; Walker, C. L.; Rusev, G.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Becvar, F.; Krticka, M.; Kroll, J.; Agvaanluvsan, U.; Dashdorj, D.; Erdenehuluun, B.; Tsend-Ayush, T.

    2013-04-19

    Neutron capture experiments on highly enriched {sup 117,119}Sn isotopes were performed with the DANCE detector array located at the Los Alamos Neutron Science Center. The DANCE detector provides detailed information about the multi-step {gamma}-ray cascade following neutron capture. Analysis of the experimental data provides important information to improve understanding of the neutron capture reaction, including a test of the statistical model, the assignment of spins and parities of neutron resonances, and information concerning the Photon Strength Function (PSF) and Level Density (LD) below the neutron separation energy. Preliminary results for the (n,{gamma}) reaction on {sup 117,119}Sn are presented. Resonance spins of the odd-A tin isotopes were almost completely unknown. Resonance spins and parities have been assigned via analysis of the multi-step {gamma}-ray spectra and directional correlations.

  5. Compound specific stable isotope analysis vs. bulk stable isotope analysis of agricultural food products

    NASA Astrophysics Data System (ADS)

    Psomiadis, David; Horváth, Balázs; Nehlich, Olaf; Bodiselitsch, Bernd

    2015-04-01

    The bulk analysis of stable isotopes (carbon, nitrogen, sulphur, oxygen and hydrogen) from food staples is a common tool for inferring origin and/or fraud of food products. Many studies have shown that bulk isotope analyses of agricultural products are able to separate large geographical areas of food origin. However, in micro-localities (regions, districts, and small ranges) these general applications fail in precision and discriminative power. The application of compound specific analysis of specific components of food products helps to increase the precision of established models. Compound groups like fatty acids (FAMEs), vitamins or amino acids can help to add further detailed information on physiological pathways and local conditions (micro-climate, soil, water availability) and therefore might add further information for the separation of micro-localities. In this study we are aiming to demonstrate the power and surplus of information of compound specific isotope analysis in comparison to bulk analysis of agricultural products (e.g. olive oil, cereal crops or similar products) and discuss the advantages and disadvantages of such (labor intense) analysis methods. Here we want to identify tools for further detailed analysis of specific compounds with high powers of region separation for better prediction models.

  6. Atomic Weights and Isotopic Compositions

    National Institute of Standards and Technology Data Gateway

    SRD 144 Atomic Weights and Isotopic Compositions (Web, free access)   The atomic weights are available for elements 1 through 111, and isotopic compositions or abundances are given when appropriate.

  7. Isotopic decoupling during porous melt flow: A case-study in the Lherz peridotite

    NASA Astrophysics Data System (ADS)

    Le Roux, V.; Bodinier, J.-L.; Alard, O.; O'Reilly, S. Y.; Griffin, W. L.

    2009-03-01

    Most peridotite massifs and mantle xenoliths show a wide range of isotopic variations, often involving significant decoupling between Hf, Nd and Sr isotopes. These variations are generally ascribed either to mingling of individual components of contrasted isotopic compositions or to time integration of parent-element enrichment by percolating melts/fluids, superimposed onto previous depletion event(s). However, strong isotopic decoupling may also arise during porous flow as a result of daughter-elements fractionation during solid-liquid interaction. Although porous flow is recognized as an important process in mantle rocks, its effects on mantle isotopic variability have been barely investigated so far. The peridotites of the Lherz massif (French Pyrenees) display a frozen melt percolation front separating highly refractory harzburgites from refertilized lherzolites. Isotopic signatures observed at the melt percolation front show a strong decoupling of Hf from Nd and Sr isotopes that cannot be accounted for by simple mixing involving the harzburgite protolith and the percolating melt. Using one dimensional percolation-diffusion and percolation-reaction modeling, we show that these signatures represent transient isotopic compositions generated by porous flow. These signatures are governed by a few critical parameters such as daughter element concentrations in melt and peridotite, element diffusivity, and efficiency of isotopic homogenization rather than by the chromatographic effect of melt transport and the refertilization reaction. Subtle variations in these parameters may generate significant inter-isotopic decoupling and wide isotopic variations in mantle rocks.

  8. DEEP WATER ISOTOPIC CURRENT ANALYZER

    DOEpatents

    Johnston, W.H.

    1964-04-21

    A deepwater isotopic current analyzer, which employs radioactive isotopes for measurement of ocean currents at various levels beneath the sea, is described. The apparatus, which can determine the direction and velocity of liquid currents, comprises a shaft having a plurality of radiation detectors extending equidistant radially therefrom, means for releasing radioactive isotopes from the shaft, and means for determining the time required for the isotope to reach a particular detector. (AEC)

  9. Carbon isotope controlled molecular switches

    NASA Astrophysics Data System (ADS)

    Foster, Brian K.

    Single molecules represent one fundamental limit to the downscaling of electronics. As a prototype element for carbon-based nanoscale science and technology, the detailed behavior of carbon monoxide (CO) on the copper surface Cu(111) has been investigated. These investigations span from individual carbon isotope resolution, to single molecules, to compact clusters assembled by molecular manipulation via a homemade scanning tunneling microscope (STM). Sub-nanoscale devices, composed of only a few molecules, which exploit both lone CO properties and molecule-molecule interaction, have been designed and assembled. The devices function as bi-stable switches and can serve as classical bits with densities > 50 Tbits/cm2. Operated in the nuclear mass sensitive regime, each switch can also function as a molecular "centrifuge" capable of identifying the isotope of a single carbon atom in real-time. A model, based on electron-vibron couping and inelastic tunneling, has been developed and explains the dynamic behavior of the switch. The interaction between pairs of switches was also explored and it was found that their behavior ranges from completely independent to strongly coupled. Larger nanostructures, which were composed of many sub-switches organized to leverage the fully coupled interaction, link two spatially separated "bits" on the surface. Such a linked system can set or read a state non-locally, which is equivalent to bidirectional information transfer. The linked system has also exhibited logic functionality. These experiments demonstrate scalable molecular cells for information storage, and for information processing through cellular automata logic schemes.

  10. Quantitative ion-exchange separation of plutonium from impurities

    SciTech Connect

    Pietri, C.E.; Freeman, B.P.; Weiss, J.R.

    1981-09-01

    The methods used at the New Brunswick Laboratory for the quantitative ion exchange separation of plutonium from impurities prior to plutonium assay are described. Other ion exchange separation procedures for impurity determination and for isotopic abundance measurements are given. The primary technique used consists of sorption of plutonium(IV) in 8N HNO/sub 3/ on Dowex-1 anion exchange resin and elution of the purified plutonium with 0.3N HCl-0.01N HF. Other methods consist of the anion exchange separation of plutonium(IV) in 12N HCl and the cation exchange separation of plutonium(III) in 0.2 N HNO/sub 3/. The application of these procedures to the subsequent assay of plutonium, isotopic analysis, and impurity determination is described.

  11. Uranium Isotopic Analysis with the FRAM Isotopic Analysis Code

    SciTech Connect

    Duc T. Vo; Thomas E. Sampson

    1999-05-01

    FRAM is the acronym for Fixed-energy Response-function Analysis with Multiple efficiency. This software was developed at Los Alamos National Laboratory originally for plutonium isotopic analysis. Later, it was adapted for uranium isotopic analysis in addition to plutonium. It is a code based on a self-calibration using several gamma-ray peaks for determining the isotopic ratios. The versatile-parameter database structure governs all facets of the data analysis. User editing of the parameter sets allows great flexibility in handling data with different isotopic distributions, interfering isotopes, and different acquisition parameters such as energy calibration and detector type.

  12. Sulfur isotopic data

    SciTech Connect

    Rye, R.O.

    1987-01-01

    Preliminary sulfur isotope data have been determined for samples of the Vermillion Creek coal bed and associated rocks in the Vermillion Creek basin and for samples of evaporites collected from Jurassic and Triassic formations that crop out in the nearby Uinta Mountains. The data are inconclusive, but it is likely that the sulfur in the coal was derived from the evaporites.

  13. Forensic Stable Isotope Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  14. Attomole quantitation of protein separations with accelerator mass spectrometry

    SciTech Connect

    Vogel, J S; Grant, P G; Buccholz, B A; Dingley, K; Turteltaub, K W

    2000-12-15

    Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as 14C to sub-attomole sensitivity. We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5% . Micro-proton-induced-xray-emission quantifies elemental abundances in separated metalloprotein samples to nanogram amounts and is capable of quantifying phosphorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.

  15. Separation of Armchair SWNTs by Using Polymer Conformation Guided Assembly

    DTIC Science & Technology

    2013-08-22

    30 Publications 36 Reference List 38     2 Introduction Single-walled carbon nanotubes (SWNTs) are among the most...with 12, the polymer 15 of linear geometry also forms the donor-acceptor complex resulting in enhanced interactions with graphene or carbon nanotubes .32...Band engineering of oxygen doped single-walled carbon nanotubes , NANOSCALE 2011, 6 2465-2468.  R. Gunasingh; C. Kah; K. Quarles; et al

  16. Observation of new neutron-deficient isotopes with Z ≥ 92 in multinucleon transfer reactions

    NASA Astrophysics Data System (ADS)

    Devaraja, H. M.; Heinz, S.; Beliuskina, O.; Comas, V.; Hofmann, S.; Hornung, C.; Münzenberg, G.; Nishio, K.; Ackermann, D.; Gambhir, Y. K.; Gupta, M.; Henderson, R. A.; Heßberger, F. P.; Khuyagbaatar, J.; Kindler, B.; Lommel, B.; Moody, K. J.; Maurer, J.; Mann, R.; Popeko, A. G.; Shaughnessy, D. A.; Stoyer, M. A.; Yeremin, A. V.

    2015-09-01

    In deep inelastic multinucleon transfer reactions of 48Ca + 248Cm we observed about 100 residual nuclei with proton numbers between Z = 82 and Z = 100. Among them, there are five new neutron-deficient isotopes: 216U, 219Np, 223Am, 229Am and 233Bk. As separator for the transfer products we used the velocity filter SHIP of GSI while the isotope identification was performed via the α decay chains of the nuclei. These first results reveal that multinucleon transfer reactions together with here applied fast and sensitive separation and detection techniques are promising for the synthesis of new isotopes in the region of heaviest nuclei.

  17. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography.

    PubMed

    Ismail, Ibrahim; Fawzy, Ahmed S; Ahmad, Mohammad I; Aly, Hisham F; Nomura, Masao; Fujii, Yasuhiko

    2013-03-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε's, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε's, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated.

  18. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography

    PubMed Central

    Ismail, Ibrahim; Fawzy, Ahmed S.; Ahmad, Mohammad I.; Aly, Hisham F.; Nomura, Masao; Fujii, Yasuhiko

    2012-01-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε’s, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε’s, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated. PMID:25685410

  19. Accuracy of delta 18O isotope ratio measurements on the same sample by continuous-flow isotope-ratio mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The doubly labeled water method is considered the reference method to measure energy expenditure. Conventional mass spectrometry requires a separate aliquot of the same sample to be prepared and analyzed separately. With continuous-flow isotope-ratio mass spectrometry, the same sample could be analy...

  20. Water isotopes in desiccating lichens

    PubMed Central

    Cuntz, Matthias; Máguas, Cristina; Lakatos, Michael

    2009-01-01

    The stable isotopic composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in non-vascular, poikilohydric organisms such as lichens and bryophytes. To understand basic isotope exchange processes of non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrate with the isotopic composition of surrounding water vapour. A model was developed as a proof of concept that accounts for the specific water relations of these poikilohydric organisms. The approach incorporates first their variable thallus water potential and second a compartmentation of the thallus water into two isotopically distinct but connected water pools. Moreover, the results represent first steps towards the development of poikilohydric organisms as a recorder of ambient vapour isotopic composition. PMID:19888598