Science.gov

Sample records for radioactive chemical elements

  1. RADIOACTIVE CHEMICAL ELEMENTS IN THE ATOMIC TABLE.

    SciTech Connect

    HOLDEN, N.E.

    2005-08-13

    In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular elements has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass number to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number is inconsistent with the primary purpose of the Table, i.e., to provide accurate values of ''these constants'' for use in chemical calculations. In addition to the Table of Atomic Weights, the Commission included an auxiliary Table of Radioactive Elements for the first time, where the entry would be the isotope of that element which was most stable, i.e., it had the longest known half-life. In their 1973 report, the Commission noted that the users of the Atomic Weights Table were dissatisfied with the omission of values in the Table for some elements and it was decided to reintroduce the mass number for elements. In their 1983 report, the Commission decided that radioactive elements were considered to lack a characteristic terrestrial isotopic composition, from which an atomic weight value could be calculated to

  2. TABLE OF RADIOACTIVE ELEMENTS.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

    For those chemical elements which have no stable nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.

  3. Tabulation of thermodynamic data for chemical reactions involving 58 elements common to radioactive waste package systems

    SciTech Connect

    Benson, L.V.; Teague, L.S.

    1980-08-01

    The rate of release and migration of radionuclides from a nuclear waste repository to the biosphere is dependent on chemical interactions between groundwater, the geologic host rock, and the radioactive waste package. For the purpose of this report, the waste package includes the wasteform, canister, overpack, and repository backfill. Chemical processes of interest include sorption (ion exchange), dissolution, complexation, and precipitation. Thermochemical data for complexation and precipitation calculations for 58 elements common to the radioactive waste package are presented. Standard free energies of formation of free ions, complexes, and solids are listed. Common logarithms of equilibrium constants (log K's) for speciation and precipitation reactions are listed. Unless noted otherwise, all data are for 298.15/sup 0/K and one atmosphere.

  4. Radioactive elements in stellar atmospheres

    SciTech Connect

    Gopka, Vira; Yushchenko, Alexander; Goriely, Stephane; Shavrina, Angelina; Kang, Young Woon

    2006-07-12

    The identification of lines of radioactive elements (Tc, Pm and elements with 83chemically peculiar stars HD101065, HR465, HD965 is made. Three possible explanations are proposed: natural radioactive decay of Th and U in the upper levels of stellar atmospheres, contamination of stellar atmosphere by recent SN explosion, and spallation reactions.

  5. Table of radioactive elements

    SciTech Connect

    Holden, N.E.

    1985-01-01

    As has been the custom in the past, the Commission publishes a table of relative atomic masses and halflives of selected radionuclides. The information contained in this table will enable the user to calculate the atomic weight for radioactive materials with a variety of isotopic compositions. The atomic masses have been taken from the 1984 Atomic Mass Table. Some of the halflives have already been documented.

  6. Elemental Chemical Puzzlers

    ERIC Educational Resources Information Center

    Thomas, Nicholas C.

    2009-01-01

    This paper provides nine short chemically based puzzles or problems extensible for use with students from middle school to college. Some of these will strengthen students' recognition of individual elements and element names. Others require students to focus on the salient properties of given chemical elements.

  7. Radioactive dating of the elements

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Thielemann, Friedrich-Karl; Truran, James W.

    1991-01-01

    The extent to which an accurate determination of the age of the Galaxy, and thus a lower bound on the age of the universe, can be obtained from radioactive dating is discussed. Emphasis is given to the use of the long-lived radioactive nuclei Re-187, Th-232, U-238, and U-235. The nature of the production sites of these and other potential Galactic chronometers is examined along with their production ratios. Age determinations from models of nucleocosmochronology are reviewed and compared with age determination from stellar sources and age constraints form cosmological considerations.

  8. STATUS OF RADIOACTIVE ELEMENTS IN THE ATOMIC WEIGHTS TABLE.

    SciTech Connect

    HOLDEN,N.E.

    2003-08-08

    During discussions within the Inorganic Chemistry Division Committee, that dealt with the Periodic Table of the Chemical Elements and the official IUPAC position on its presentation, the following question was raised. When the various chemical elements are presented, each with their appropriate atomic weight value, how should the radioactive elements be presented? The Atomic Weights Commission has treated this question in a number of different ways during the past century, almost in a random manner. This report reviews the position that the Commission has taken as a function of time, as a prelude to a discussion in Ottawa about how the Commission should resolve this question for the future.

  9. Chemical characterization of element 112.

    PubMed

    Eichler, R; Aksenov, N V; Belozerov, A V; Bozhikov, G A; Chepigin, V I; Dmitriev, S N; Dressler, R; Gäggeler, H W; Gorshkov, V A; Haenssler, F; Itkis, M G; Laube, A; Lebedev, V Ya; Malyshev, O N; Oganessian, Yu Ts; Petrushkin, O V; Piguet, D; Rasmussen, P; Shishkin, S V; Shutov, A V; Svirikhin, A I; Tereshatov, E E; Vostokin, G K; Wegrzecki, M; Yeremin, A V

    2007-05-01

    The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury. However, the production and identification methods used cast doubt on the validity of this result. Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of (283)112 through the alpha decay of the short-lived (287)114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of (283)112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides. PMID:17476264

  10. Chemical characterization of element 112

    NASA Astrophysics Data System (ADS)

    Eichler, R.; Aksenov, N. V.; Belozerov, A. V.; Bozhikov, G. A.; Chepigin, V. I.; Dmitriev, S. N.; Dressler, R.; Gäggeler, H. W.; Gorshkov, V. A.; Haenssler, F.; Itkis, M. G.; Laube, A.; Lebedev, V. Ya.; Malyshev, O. N.; Oganessian, Yu. Ts.; Petrushkin, O. V.; Piguet, D.; Rasmussen, P.; Shishkin, S. V.; Shutov, A. V.; Svirikhin, A. I.; Tereshatov, E. E.; Vostokin, G. K.; Wegrzecki, M.; Yeremin, A. V.

    2007-05-01

    The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury. However, the production and identification methods used cast doubt on the validity of this result. Here we report a more reliable chemical characterization of element 112, involving the production of two atoms of 283112 through the alpha decay of the short-lived 287114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of 283112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides.

  11. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    SciTech Connect

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  12. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    SciTech Connect

    P. Bernot

    2005-07-13

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

  13. Dissolved Concentration Limits of Radioactive Elements

    SciTech Connect

    Y. Chen; E.R. Thomas; F.J. Pearson; P.L. Cloke; T.L. Steinborn; P.V. Brady

    2003-06-20

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of radioactive elements under possible repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, and measurements made in laboratory experiments and field work. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 radioactive elements (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium), which are important to calculated dose. Model outputs are mainly in the form of look-up tables plus one or more uncertainty terms. The rest are either in the form of distributions or single values. The results of this analysis are fundamental inputs for total system performance assessment to constrain the release of these elements from waste packages and the engineered barrier system. Solubilities of plutonium, neptunium, uranium, americium, actinium, thorium, protactinium, lead, and radium have been re-evaluated using the newly updated thermodynamic database (Data0.ymp.R2). For all of the actinides, identical modeling approaches and consistent environmental conditions were used to develop solubility models in this revision. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, activity coefficients, and selection of solubility controlling phase have been quantified or otherwise addressed. Moreover, a new blended plutonium solubility model has been developed in this revision, which gives a mean solubility that is three orders of magnitude lower than the plutonium solubility model used for the Total System Performance Assessment for the Site Recommendation. Two alternative neptunium solubility models have also been

  14. Radioactive Elements in the Standard Atomic Weights Table.

    SciTech Connect

    Holden,N.E.

    2007-08-04

    In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (or longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular element has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number is inconsistent with the primary purpose of the Table, i.e., to provide accurate values of 'these constants' for use in various chemical calculations. In addition to the Table of Atomic Weights, the Commission included an auxiliary Table of Radioactive Elements for the first time, where the entry would be the isotope of that element which was the most stable, i.e., the one with the longest known half-life. In their 1973 Report, the Commission noted that the users of the main Table of Atomic Weights were dissatisfied with the omission of values for some elements in that Table and it was decided to reintroduce the mass number for the radioactive elements into the main Table. In their 1983 Report, the Commission decided that radioactive elements were considered to lack a characteristic terrestrial isotopic composition

  15. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

    Keller, J.F.; Stewart, T.L.

    1991-07-01

    The Hanford Site was established in 1944 to produce plutonium for defense. During the past four decades, a number of reactors, processing facilities, and waste management facilities have been built at Hanford for plutonium production. Generally, Hanford`s 100 Area was dedicated to reactor operation; the 200 Area to fuel reprocessing, plutonium recovery, and waste management; and the 300 Area to fuel fabrication and research and development. Wastes generated from these operations included highly radioactive liquid wastes, which were discharged to single- and double-shell tanks; solid wastes, including both transuranic (TRU) and low-level wastes, which were buried or discharged to caissons; and waste water containing low- to intermediate-level radioactivity, which was discharged to the soil column via near-surface liquid disposal units such as cribs, ponds, and retention basins. Virtually all of the wastes contained hazardous chemical as well as radioactive constituents. This paper will focus on the hazardous chemical components of the radioactive mixed waste generated by plutonium production at Hanford. The processes, chemicals used, methods of disposition, fate in the environment, and actions being taken to clean up this legacy are described by location.

  16. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

    Keller, J.F.; Stewart, T.L.

    1991-07-01

    The Hanford Site was established in 1944 to produce plutonium for defense. During the past four decades, a number of reactors, processing facilities, and waste management facilities have been built at Hanford for plutonium production. Generally, Hanford's 100 Area was dedicated to reactor operation; the 200 Area to fuel reprocessing, plutonium recovery, and waste management; and the 300 Area to fuel fabrication and research and development. Wastes generated from these operations included highly radioactive liquid wastes, which were discharged to single- and double-shell tanks; solid wastes, including both transuranic (TRU) and low-level wastes, which were buried or discharged to caissons; and waste water containing low- to intermediate-level radioactivity, which was discharged to the soil column via near-surface liquid disposal units such as cribs, ponds, and retention basins. Virtually all of the wastes contained hazardous chemical as well as radioactive constituents. This paper will focus on the hazardous chemical components of the radioactive mixed waste generated by plutonium production at Hanford. The processes, chemicals used, methods of disposition, fate in the environment, and actions being taken to clean up this legacy are described by location.

  17. Radioactive decay as a forced nuclear chemical process: Phenomenology

    NASA Astrophysics Data System (ADS)

    Timashev, S. F.

    2015-11-01

    Concepts regarding the mechanism of radioactive decay of nuclei are developed on the basis of a hypothesis that there is a dynamic relationship between the electronic and nuclear subsystems of an atom, and that fluctuating initiating effects of the electronic subsystem on a nucleus are possible. Such relationship is reflected in experimental findings that show the radioactive decay of nuclei might be determined by a positive difference between the mass of an initial nucleus and the mass of an atom's electronic subsystem, i.e., the mass of the entire atom (rather than that of its nucleus) and the total mass of the decay products. It is established that an intermediate nucleus whose charge is lower by unity than the charge of the initial radioactive nucleus is formed as a result of the above fluctuating stimuli that initiate radioactive decay, and its nuclear matter is thus in an unbalanced metastable state of inner shakeup, affecting the quark subsystem of nucleons. The intermediate nucleus thus experiences radioactive decay with the emission of α or β particles. At the same time, the high energy (with respect to the chemical scale) of electrons in plasma served as a factor initiating the processes in different nuclear chemical transformations and radioactive decays in low-temperature plasma studied earlier, particularly during the laser ablation of metals in aqueous solutions of different compositions and in near-surface cathode layers upon glow discharge. It is shown that a wide variety of nucleosynthesis processes in the Universe can be understood on the same basis, and a great many questions regarding the formation of light elements in the solar atmosphere and some heavy elements (particularly p-nuclei) in the interiors of massive stars at late stages of their evolution can also be resolved.

  18. RADIOACTIVE ELEMENTS IN THE STANDARD ATOMIC WEIGHTS TABLE

    SciTech Connect

    Holden, N.E.; Holden, N.; Holden,N.E.

    2011-07-27

    In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (or longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular element has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number is inconsistent with the primary purpose of the Table, i.e., to provide accurate values of 'these constants' for use in various chemical calculations. In addition to the Table of Atomic Weights, the Commission included an auxiliary Table of Radioactive Elements for the first time, where the entry would be the isotope of that element which was the most stable, i.e., the one with the longest known half-life. In their 1973 Report, the Commission noted that the users of the main Table of Atomic Weights were dissatisfied with the omission of values for some elements in that Table and it was decided to reintroduce the mass number for the radioactive elements into the main Table. In their 1983 Report, the Commission decided that radioactive elements were considered to lack a characteristic terrestrial isotopic composition

  19. Chemical characterization of bohrium (element 107)

    PubMed

    Eichler; Bruchle; Dressler; Dullmann; Eichler; Gaggeler; Gregorich; Hoffman; Hubener; Jost; Kirbach; Laue; Lavanchy; Nitsche; Patin; Piguet; Schadel; Shaughnessy; Strellis; Taut; Tobler; Tsyganov; Turler; Vahle; Wilk; Yakushev

    2000-09-01

    The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table. PMID:10993071

  20. Chemical characterization of bohrium (element 107)

    NASA Astrophysics Data System (ADS)

    Eichler, R.; Brüchle, W.; Dressler, R.; Düllmann, Ch. E.; Eichler, B.; Gäggeler, H. W.; Gregorich, K. E.; Hoffman, D. C.; Hübener, S.; Jost, D. T.; Kirbach, U. W.; Laue, C. A.; Lavanchy, V. M.; Nitsche, H.; Patin, J. B.; Piguet, D.; Schädel, M.; Shaughnessy, D. A.; Strellis, D. A.; Taut, S.; Tobler, L.; Tsyganov, Y. S.; Türler, A.; Vahle, A.; WiIk, P. A.; Yakushev, A. B.

    2000-09-01

    The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected: electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements, now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available. In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table, whereas element 106 behaves in accordance with the expected periodicity. Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table.

  1. HISTORY OF THE ORIGIN OF THE CHEMICAL ELEMENTS AND THEIR DISCOVERIES.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

    What do we mean by a chemical element? A chemical element is matter, all of whose atoms are alike in having the same positive charge on the nucleus and the same number of extra-nuclear electrons. As we shall see in the following elemental review, the origin of the chemical elements show a wide diversity with some of these elements having an origin in antiquity, other elements having been discovered within the past few hundred years and still others have been synthesized within the past fifty years via nuclear reactions on heavy elements since these other elements are unstable and radioactive and do not exist in nature.

  2. The Behavior of Chemical Elements in Stars

    NASA Astrophysics Data System (ADS)

    Jaschek, Carlos; Jaschek, Mercedes

    1995-06-01

    Part I. Quantitative Description of Each of 80 Chemical Elements; Part II: 1. Behaviour of molecules in stars; 2. Groups of elements; 3. Chromospheres and coronas; Part III: 1. Terminology of spectral lines; 2. Selection of stars; 3. Line identification; 4. Equivalent widths; 5. Abundances; 6. Afterthoughts; Part IV: 1. Periodic Table; 2. Elements in alphabetical order of names; 3. Elements in alphabetical order of formula; 4. Elements ordered by atomic number; 5. Abundances of chemical elements; 6. Spectral type and surface gravity as a function of luminosity class. 7. Effective temperature; References; Index.

  3. The Behavior of Chemical Elements in Stars

    NASA Astrophysics Data System (ADS)

    Jaschek, Carlos; Jaschek, Mercedes

    2009-03-01

    Part I. Quantitative Description of Each of 80 Chemical Elements; Part II: 1. Behaviour of molecules in stars; 2. Groups of elements; 3. Chromospheres and coronas; Part III: 1. Terminology of spectral lines; 2. Selection of stars; 3. Line identification; 4. Equivalent widths; 5. Abundances; 6. Afterthoughts; Part IV: 1. Periodic Table; 2. Elements in alphabetical order of names; 3. Elements in alphabetical order of formula; 4. Elements ordered by atomic number; 5. Abundances of chemical elements; 6. Spectral type and surface gravity as a function of luminosity class. 7. Effective temperature; References; Index.

  4. Thermodynamic Data For 50 Chemical Elements

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford; Reno, Martin A.

    1995-01-01

    Report presents data on thermo-dynamic properties of 50 chemical elements, isotope (deuterium) of one of elements, and electron gas, all in standard reference states. Data tabulated as functions of temperature; also given in form of least-squares-fit coefficients of two functional forms for heat capacities at constant pressure in standard states, with constants of integration for enthalpy and entropy.

  5. Calculation of chemical quantities for the radioactive liquid waste treatment facility

    SciTech Connect

    Del Signore, John C.; McClenahan, Robert L.

    2007-03-01

    The Radioactive Liquid Waste Treatment Facility (RLWTF) receives, stores, and treats both low-level and transuranic radioactive liquid wastes (RLW). Treatment of RLW requires the use of different chemicals. Examples include the use of calcium oxide to precipitate metals and radioactive elements from the radioactive liquid waste, and the use of hydrochloric acid to clean membrane filters that are used in the treatment process. The RL WTF is a Hazard Category 2 nuclear facility, as set forth in the LANL Final Safety Analysis Report of October 1995, and a DOE letter of March 11, 1999. A revised safety basis is being prepared for the RLWTF, and will be submitted to the NNSA in early 2007. This set of calculations establishes maximum chemical quantities that will be used in the 2007 safety basis.

  6. Chemical investigation of hassium (element 108).

    PubMed

    Düllmann, Ch E; Brüchle, W; Dressler, R; Eberhardt, K; Eichler, B; Eichler, R; Gäggeler, H W; Ginter, T N; Glaus, F; Gregorich, K E; Hoffman, D C; Jäger, E; Jost, D T; Kirbach, U W; Lee, D M; Nitsche, H; Patin, J B; Pershina, V; Piguet, D; Qin, Z; Schädel, M; Schausten, B; Schimpf, E; Schött, H-J; Soverna, S; Sudowe, R; Thörle, P; Timokhin, S N; Trautmann, N; Türler, A; Vahle, A; Wirth, G; Yakushev, A B; Zielinski, P M

    2002-08-22

    The periodic table provides a classification of the chemical properties of the elements. But for the heaviest elements, the transactinides, this role of the periodic table reaches its limits because increasingly strong relativistic effects on the valence electron shells can induce deviations from known trends in chemical properties. In the case of the first two transactinides, elements 104 and 105, relativistic effects do indeed influence their chemical properties, whereas elements 106 and 107 both behave as expected from their position within the periodic table. Here we report the chemical separation and characterization of only seven detected atoms of element 108 (hassium, Hs), which were generated as isotopes (269)Hs (refs 8, 9) and (270)Hs (ref. 10) in the fusion reaction between (26)Mg and (248)Cm. The hassium atoms are immediately oxidized to a highly volatile oxide, presumably HsO(4), for which we determine an enthalpy of adsorption on our detector surface that is comparable to the adsorption enthalpy determined under identical conditions for the osmium oxide OsO(4). These results provide evidence that the chemical properties of hassium and its lighter homologue osmium are similar, thus confirming that hassium exhibits properties as expected from its position in group 8 of the periodic table. PMID:12192405

  7. Chemical and catalytic properties of elemental carbon

    SciTech Connect

    Chang, S.G.; Brodzinsky, R.; Gundel, L.A.; Novakov, T.

    1980-10-01

    Elemental carbon particles resulting from incomplete combustion of fossil fuel are one of the major constituents of airborne particulate matter. These particles are a chemically and catalytically active material and can be an effective carrier for other toxic air pollutants through their adsorptive capability. The chemical, adsorptive, and catalytic behaviors of carbon particles depend very much on their crystalline structure, surface composition, and electronic properties. This paper discusses these properties and examines their relevance to atmospheric chemistry.

  8. Physical-chemical studies of transuranium elements

    SciTech Connect

    Peterson, J.R.

    1991-01-01

    Major advances in our continuing program to determine, interpret, and correlate the basic chemical and physical properties of the transuranium elements are summarized. Research topics include: Molar enthalpies of formation of BaCmO{sub 3} and BaCfO{sub 3}; luminescence of europium oxychloride at various pressures; and anti-stokes luminescence of selected actinide (III) compounds. 42 refs., 4 figs., 2 tabs.

  9. In-Situ Chemical Precipitation of Radioactive Liquid Waste - 12492

    SciTech Connect

    Osmanlioglu, Ahmet Erdal

    2012-07-01

    This paper presented in-situ chemical precipitation for radioactive liquid waste by using chemical agents. Results are reported on large-scale implementation on the removal of {sup 137}Cs, {sup 134}Cs and {sup 60}Co from liquid radioactive waste generating from Nuclear Research and Training Centre. Total amount of liquid radioactive waste was 35 m{sup 3} and main radionuclides were Cs-137, Cs- 134 and Co-60. Initial radioactivity concentration of the liquid waste was 2264, 17 and 9 Bq/liter for Cs-137, Cs-134 and Co-60 respectively. Potassium ferro cyanide was selected as chemical agent at high pH levels 8-10 according to laboratory tests. After the process, radioactive sludge precipitated at the bottom of the tank and decontaminated clean liquid was evaluated depending on discharge limits. By this precipitation method decontamination factors were determined as 60, 9 and 17 for Cs-137, Cs-134 and Co-60 respectively. At the bottom of the tank radioactive sludge amount was 0.98 m{sup 3}. It was transferred by sludge pumps to cementation unit for solidification. By in situ chemical processing 97% of volume reduction was achieved. Using the optimal concentration of 0.75 M potassium ferro cyanide about 98% of the {sup 137}Cs can be removed at pH 8. The Potassium ferro cyanide precipitation method could be used successfully in large scale applications with nickel and ferrum agents for removal of Cs-137, Cs-134 and Co- 60. Although DF values of laboratory test were much higher than in-situ implementation, liquid radioactive waste was decontaminated successfully by using potassium ferro cyanide. Majority of liquid waste were discharged as clean liquid. %97.2 volumetric amount of liquid waste was cleaned and discharged at the original site. Reduced amount of sludge transportation in drums is more economical and safer method than liquid transportation. Although DF values could be different for each of applications related to main specifications of original liquid waste, this

  10. Chemical investigations of Element 108, Hassium (Hs)

    SciTech Connect

    Dullmann, Christoph E.

    2003-07-03

    The basic aim of chemistry experiments of transactinide elements (TAN) is to establish their place in the periodic table of the elements, i.e. to determine if their chemical behavior is similar to the one of supposed homologs. In this contribution I will try to give an overview of all chemical experiments on element 108, hassium (Hs) that have been reported to date. Based on the systematics of the periodic table, Hs is expected to be a member of group 8 and therefore homologous to osmium (Os) and ruthenium (Ru). As a member of the transactinide series, its experimental investigation is complicated by low production cross-sections and short half-lives. It has therefore been successfully investigated only recently. Already in the seventies of the last century, several authors mentioned the tetroxides of the two heavier group 8 elements, Ru and Os, to be very outstanding compounds with respect to their unusually high volatility. A possible HsO{sub 4} was considered suitable for isolating Hs from unwanted by-products of the nuclear production reaction. While RuO{sub 4}4 is rather unstable, OsO{sub 4} is well-known to be a stable compound and is widely used in organic chemistry. Recent theoretical calculations on the electronic structure and properties of Hs [5,6] predict the formation of a stable HsO{sub 4} whose properties should be similar to the ones of OsO{sub 4}. This is in agreement with an extrapolation of the trend established in group 8 of the periodic table by Ru and Os [7]. All of the reported experiments on the chemistry of Hs therefore aimed at a formation of this compound. Hs was discovered in 1984, when Muenzenberg et al. reported the observation of a correlated decay-chain from {sup 265}Hs formed in the nuclear reaction {sup 58}Fe({sup 208}Pb; n) [8]. However, its half-life is only 1.55 ms, too short for a successful chemistry experiment. Early chemistry experiments therefore aimed at the production and detection of more neutron-rich Hs isotopes which

  11. System for chemically digesting low level radioactive, solid waste material

    DOEpatents

    Cowan, Richard G.; Blasewitz, Albert G.

    1982-01-01

    An improved method and system for chemically digesting low level radioactive, solid waste material having a high through-put. The solid waste material is added to an annular vessel (10) substantially filled with concentrated sulfuric acid. Concentrated nitric acid or nitrogen dioxide is added to the sulfuric acid within the annular vessel while the sulfuric acid is reacting with the solid waste. The solid waste is mixed within the sulfuric acid so that the solid waste is substantilly fully immersed during the reaction. The off gas from the reaction and the products slurry residue is removed from the vessel during the reaction.

  12. Attempts to chemically investigate element 112

    SciTech Connect

    Eichler, R.; Bruchle, W.; Buda, R.; Burger, S.; Dressler, R.; Dullmann, C.E.; Dvorak, J.; Eberhardt, K.; Eichler, B.; Folden, C.M.; Gaggeler, H.W.; Gregorich, K.E.; Haenssler, F.; Hoffman, D.C.; Hummrich,H.; Jager, E.; Kratz, J.V.; Kuczewski, B.; Liebe, D.; Nayak, D.; Nitsche,H.; Piguet, D.; Qin, Z.; Rieth, U.; Schadel, M.; Schausten, B.; Schimpf,E.; Semchenkov, A.; Soverna, S.; Sudowe, R.; Trautmann, N.; Thorle, P.; Turler, A.; Wierczinski, B.; Wiehl, N.; Wilk, P.A.; Wirth, G.; Yakushev,A.B.; von Zweidorf, A.

    2005-09-15

    Two experiments aiming at the chemical investigation of element 112 produced in the heavy ion induced nuclear fusion reaction of Ca-48 with U-238 were performed at the Geselischaft fur Schwerionenforschung (GSI), Darmstadt, Germany. Both experiments were designed to determine the adsorption enthalpy of element 112 on a gold surface using a thermochromatography setup. The temperature range covered in the thermochromatography experiments allowed the adsorption of Hg at about 35 degrees C and of Rn at about -180 degrees C. Reports from the Flerov Laboratory for Nuclear Reactions (FLNR), Dubna, Russia claim production of a 5-min spontaneous fission (SF) activity assigned to 211112 for the U-238 (Ca-48,3n) (283)112 reaction. Hence, Experiment I was designed to detect spontaneously fissioning (SF) isotopes of element 112 with half-lives (t(1/2)) longer than about 20 s. 11 high-energy events were detected. 7 events exhibit a deposition pattern resembling a chromatographic peak in the vicinity of Rn deposition. However, the energy of the events observed in Experiment I was lower than expected for a SF-decay of (283)112. Therefore, these events could not be unambiguously attributed to the decay of (283)112. In contradiction with earlier publications newer reports from FLNR Dubna claim that (283)12 decays by a-particle emission (E-alpha = 9.5 MeV) with t(1/2) = 4 s followed by a SF-decay of (279)Ds (t(1/2) = 0.2 s). Therefore, Experiment II was designed to be sensitive to both claimed decay properties of (283)112. However, during this experiment neither short alpha-SF correlations nor SF coincidences were detected. The conclusion is that (283)112 was not unambiguously detected, neither in Experiment I nor in Experiment II.

  13. Prolong Restoration of the Water Quality of River Ganga Effect of Heavy Metals and Radioactive Elements.

    PubMed

    Tare, Vinod; Basu, Subhankar

    2014-04-01

    The genesis of the present research was the belief since ages and the observations made through some studies that the water of river Ganga has unique characteristics, which allows storage of water quality even on prolong storage. Very few systematic studies have been conducted to support the contention that the Ganga water indeed has some special composition that could be attributed to its unique storage capacity. It was postulated that prolong restoration of water quality depends on the ability to arrest microbial activity that is generally responsible for deterioration in water quality on prolong storage. Hence, attempt has been made to identify the parameters that are likely to influence the prolong storage of river water. Along with Ganga river water, other three major rivers, viz. Yamuna, Godavari and Narmada, were selected for comparison. Emphasis was made on estimation of heavy metals, radioactive elements, dissolved carbon and other physicochemical parameters such as temperature, pH, alkalinity, hardness and dissolved organic carbon. Based on the available information regarding the impact of heavy metals, radioactive elements vis-à-vis the chemical composition of water on microorganisms in the aquatic environment, an overall impact score for the waters of the four Indian rivers selected in the study has been assigned. PMID:26563059

  14. Elements--A Card Game of Chemical Names and Symbols

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; Hicks, O'Dell; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    "Elements" is a competitive card game designed to help middle school students recognize and correlate the names and symbols of the most significant chemical elements. Each student is required to construct his or her own decks of playing cards--one with the names of the chemical elements and one with their corresponding symbols--and compete against…

  15. Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex.

    PubMed

    Abuhani, W A; Dasgupta-Schubert, N; Villaseñor, L M; García Avila, D; Suárez, L; Johnston, C; Borjas, S E; Alexander, S A; Landsberger, S; Suárez, M C

    2015-01-01

    The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to

  16. Turbulent mixing of chemical elements in galaxies

    NASA Astrophysics Data System (ADS)

    Pan, Liubin

    Chemical elements synthesized in stars are released into the interstellar medium (ISM) from discrete and localized events such as supernova (SN) explosions and stellar winds. The efficiency of transport and mixing of the new nucleosynthesis products in the ISM determines the degree of chemical inhomogeneity in the galaxy, which is observable in objects of the same age, such as coeval stars and the ISM today. It also has implications for the transition from metal-poor to normal star formation in high-redshift galaxies. We develop a physical mixing model for chemical homogenization in the turbulent ISM of galaxies using modern theories and methods for passive scalar turbulence. A turbulent velocity field stretches, compresses and folds tracers into structures of smaller and smaller scales that can be homogenized faster by microscopic diffusivity, the only physical process that truly mixes. From a model that incorporates this physical process, an evolution equation for the probability distribution of the tracer concentration is derived. Including the processes of new metal release, infall of low metallicity gas and incorporation of metals into new stars in the equation, we establish a new approach to investigate chemical inhomogeneity in galaxies: a kinetic equation for the metallicity probability distribution function, containing all the 1-point statistical information of the metallicity fluctuations. Motivated by a recent interpretation of ultraviolet properties of high-redshift Lyman Break Galaxies, we apply this approach to study mixing of primordial gas in these galaxies and find that primordial gas can survive for ~ 100 Myr in the presence of continuous metal sources and turbulent mixing if the unlikely efficient mixing in SN shells is excluded. Recent observations show that the Galaxy has been extremely homogeneous during most of its history. In an attempt to understand the homogeneity using our approach, we find that standard chemical evolution models without

  17. SRS: Site ranking system for hazardous chemical and radioactive waste

    SciTech Connect

    Rechard, R.P.; Chu, M.S.Y.; Brown, S.L.

    1988-05-01

    This report describes the rationale and presents instructions for a site ranking system (SRS). SRS ranks hazardous chemical and radioactive waste sites by scoring important and readily available factors that influence risk to human health. Using SRS, sites can be ranked for purposes of detailed site investigations. SRS evaluates the relative risk as a combination of potentially exposed population, chemical toxicity, and potential exposure of release from a waste site; hence, SRS uses the same concepts found in a detailed assessment of health risk. Basing SRS on the concepts of risk assessment tends to reduce the distortion of results found in other ranking schemes. More importantly, a clear logic helps ensure the successful application of the ranking procedure and increases its versatility when modifications are necessary for unique situations. Although one can rank sites using a detailed risk assessment, it is potentially costly because of data and resources required. SRS is an efficient approach to provide an order-of-magnitude ranking, requiring only readily available data (often only descriptive) and hand calculations. Worksheets are included to make the system easier to understand and use. 88 refs., 19 figs., 58 tabs.

  18. Recent achievements in chemical studies of heaviest elements

    NASA Astrophysics Data System (ADS)

    Gäggeler, H. W.

    2011-09-01

    Discovery of heavy elements up to atomic number 118 at FLNR in Dubna has paved the way to also extend chemical knowledge to heavier members of the periodic table. Recent studies on the chemical properties of Cn and element 114 are summarized that have been performed at FLNR in Dubna using the fusion reactions 48Ca + 242/244Pu.

  19. Chemical species of plutonium in Hanford radioactive tank waste

    SciTech Connect

    Barney, G.S.

    1997-10-22

    Large quantities of radioactive wastes have been generated at the Hanford Site over its operating life. The wastes with the highest activities are stored underground in 177 large (mostly one million gallon volume) concrete tanks with steel liners. The wastes contain processing chemicals, cladding chemicals, fission products, and actinides that were neutralized to a basic pH before addition to the tanks to prevent corrosion of the steel liners. Because the mission of the Hanford Site was to provide plutonium for defense purposes, the amount of plutonium lost to the wastes was relatively small. The best estimate of the amount of plutonium lost to all the waste tanks is about 500 kg. Given uncertainties in the measurements, some estimates are as high as 1,000 kg (Roetman et al. 1994). The wastes generally consist of (1) a sludge layer generated by precipitation of dissolved metals from aqueous wastes solutions during neutralization with sodium hydroxide, (2) a salt cake layer formed by crystallization of salts after evaporation of the supernate solution, and (3) an aqueous supernate solution that exists as a separate layer or as liquid contained in cavities between sludge or salt cake particles. The identity of chemical species of plutonium in these wastes will allow a better understanding of the behavior of the plutonium during storage in tanks, retrieval of the wastes, and processing of the wastes. Plutonium chemistry in the wastes is important to criticality and environmental concerns, and in processing the wastes for final disposal. Plutonium has been found to exist mainly in the sludge layers of the tanks along with other precipitated metal hydrous oxides. This is expected due to its low solubility in basic aqueous solutions. Tank supernate solutions do not contain high concentrations of plutonium even though some tanks contain high concentrations of complexing agents. The solutions also contain significant concentrations of hydroxide which competes with other

  20. PHYSICAL AND CHEMICAL MEASUREMENTS NEEDED TO SUPPORT DISPOSITION OFSAVANNAH RIVER SITE RADIOACTIVE HIGH LEVEL WASTE SLUDGE

    SciTech Connect

    Hamm, B

    2007-05-17

    Radioactive high level waste (HLW) sludge generated as a result of decades of production and manufacturing of plutonium, tritium and other nuclear materials is being removed from storage tanks and processed into a glass waste-form for permanent disposition at the Federal Repository. Characterization of this HLW sludge is a prerequisite for effective planning and execution of sludge disposition activities. The radioactivity of HLW makes sampling and analysis of the sludge very challenging, as well as making opportunities to perform characterization rare. In order to maximize the benefit obtained from sampling and analysis, a recommended list of physical property and chemical measurements has been developed. This list includes distribution of solids (insoluble and soluble) and water; densities of insoluble solids, interstitial solution, and slurry rheology (yield stress and consistency); mineral forms of solids; and primary elemental and radioactive constituents. Sampling requirements (number, type, volume, etc.), sample preparation techniques, and analytical methods are discussed in the context of pros and cons relative to end use of the data. Generation of useful sample identification codes and entry of results into a centralized database are also discussed.

  1. The problem of burying radioactive wastes containing transplutonium elements (TPE)

    SciTech Connect

    Bryzgalova, R.V.; Krivokhatskii, A.S.; Rogozin, Y.M.; Sinitsyna, G.S.

    1986-09-01

    This paper discusses the problem of burying radioactive wastes containing TPE. The most acceptable and developed method at present is that of disposal into continental, deep-lying, geological formatins. Based on an analysis of estimates of the thermal conditions on burying highly active wastes, including TPE concentrates, data on the filtration and sorption characteristics of rocks, estimates of the diffusion of radionuclide species capable of migrating, and taking into account the retention powers of rocks it is concluded that it is possible to bury such wastes in weakly permeable geological formations possessing shielding characteristics which ensure reliability and safety in burial.

  2. Exploring the Everyday Context of Chemical Elements: Discovering the Elements of Car Components

    ERIC Educational Resources Information Center

    Franco-Mariscal, Antonio Joaquín

    2015-01-01

    This paper presents a project about the chemical elements made by 15-year-old Spanish high school students of Chemistry. It focuses on context-based teaching combined with the advantages of creating a large mural which subsequently is exposed in the school. The project consisted of researching the chemical elements in the different materials that…

  3. Combustible radioactive waste treatment by incineration and chemical digestion

    SciTech Connect

    Stretz, L.A.; Crippen, M.D.; Allen, C.R.

    1980-05-28

    A review is given of present and planned combustible radioactive waste treatment systems in the US. Advantages and disadvantages of various systems are considered. Design waste streams are discussed in relation to waste composition, radioactive contaminants by amount and type, and special operating problems caused by the waste.

  4. [Impact of Radioactive Elements on Microbial Complexes in Cryogenic Soils of Yakutia].

    PubMed

    Ivanova, T I; Kuz'mina, N P; Sobakin, P I

    2016-01-01

    It has been found that microorganisms in cryogenic soils of Yakutia are resistant to the long-term impact of cesium and thorium. The number of microorganisms in the studied ecological-trophic groups does not depend on the concentrations of radioactive elements. Differences in the number of microorganisms are determined by the physicochemical conditions that are created in different horizons of the soils studied. The long-term impact of radiation (for 36 and 66 years) on microorganisms inhabiting the permafrost soils of Yakutia has developed their adaptive capacity to high concentrations of these radioactive elements. PMID:27396175

  5. Determination of rare and radioactive elements in mineral raw materials

    NASA Astrophysics Data System (ADS)

    Ostroumov, G. V.

    Methods are presented for determining scandium, rare earths, zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, rhenium, as well as uranium, radium, thorium, and their isotopes in mineral raw materials. Geological, mineralogical, and analytical characteristics are given for each of the above elements. The analytical methods discussed here include neutron activation analysis, spectrography, gravimetry, photometry, titration, and electrochemical analysis. Optimum regions are defined for each of these methods. No individual items are abstracted in this volume

  6. k0-INAA for determining chemical elements in bird feathers

    NASA Astrophysics Data System (ADS)

    França, Elvis J.; Fernandes, Elisabete A. N.; Fonseca, Felipe Y.; Antunes, Alexsander Z.; Bardini Junior, Claudiney; Bacchi, Márcio A.; Rodrigues, Vanessa S.; Cavalca, Isabel P. O.

    2010-10-01

    The k0-method instrumental neutron activation analysis ( k0-INAA) was employed for determining chemical elements in bird feathers. A collection was obtained taking into account several bird species from wet ecosystems in diverse regions of Brazil. For comparison reason, feathers were actively sampled in a riparian forest from the Marins Stream, Piracicaba, São Paulo State, using mist nets specific for capturing birds. Biological certified reference materials were used for assessing the quality of analytical procedure. Quantification of chemical elements was performed using the k0-INAA Quantu Software. Sixteen chemical elements, including macro and micronutrients, and trace elements, have been quantified in feathers, in which analytical uncertainties varied from 2% to 40% depending on the chemical element mass fraction. Results indicated high mass fractions of Br (max=7.9 mg kg -1), Co (max=0.47 mg kg -1), Cr (max=68 mg kg -1), Hg (max=2.79 mg kg -1), Sb (max=0.20 mg kg -1), Se (max=1.3 mg kg -1) and Zn (max=192 mg kg -1) in bird feathers, probably associated with the degree of pollution of the areas evaluated. In order to corroborate the use of k0-INAA results in biomonitoring studies using avian community, different factor analysis methods were used to check chemical element source apportionment and locality clustering based on feather chemical composition.

  7. Separation and recovery of radioactive and non-radioactive toxic trace elements from aqueous industrial effluents.

    PubMed

    Iyer, R H

    2003-09-01

    An update is presented on liquid membrane-based processes as viable and relevant alternatives to conventional approaches such as precipitation, solvent extraction, ion exchange processes and electrochemical techniques for the removal and recovery of some toxic and/or valuable trace metal ions including some actinides and fission products e.g. U, Am, Y etc and As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn etc from radioactive as well as non-radioactive aqueous waste solutions respectively. In particular, results of experiments aimed at developing supported liquid membrane(SLM)-based process using commercially available porous membranes and indigenously prepared track--etch membranes (TEMs) have been critically examined in laboratory studies to generate basic data needed to evaluate their utility for continuous operation without regeneration. These include effect of pore size, porosity, optimum pore size and their reusability. It is clearly demonstrated that indigenously prepared 10 microm thick TEMs with a porosity in the range of 2-5% give comparable transport rates for metal ions-matching with that of commercial membranes of much higher thickness (160 microm) and higher porosity of 60-85%. The smaller thickness of TEMs more than compensates for their lower porosity. It is shown that because of their well defined pore characteristics TEMs could serve as model supports in SLM studies. By comparing the values of permeability coefficient (P) for TEM and polytetraflouroethylene (PTFE) supports for the transport of Pb2+ chosen as a typical divalent metal ion, and using di-2 ethyl hexyl phosphoric acid (D2EHPA) as the carrier, it is unambiguously proved that diffusion of the metal complex across the membrane is the rate controlling step in metal ion transport in SLM-based processes. An overview of the experimental findings along with future outlook and suggestions for further work are presented in this paper. PMID:15242293

  8. Element synthesis calculations for stellar explosions: robust uncertainties, sensitivities, and radioactive ion beam measurements

    NASA Astrophysics Data System (ADS)

    Smith, Michael S.; Hix, W. Raphael; Parete-Koon, Suzanne; Dessieux, Luc; Ma, Zhanwen; Starrfield, Sumner; Bardayan, Daniel W.; Guidry, Michael W.; Smith, Donald L.; Blackmon, Jeffery C.; Mezzacappa, Anthony

    2004-12-01

    We utilize multiple-zone, post-processing element synthesis calculations to determine the impact of recent ORNL radioactive ion beam measurements on predictions of novae and X-ray burst simulations. We also assess the correlations between all relevant reaction rates and all synthesized isotopes, and translate nuclear reaction rate uncertainties into abundance prediction uncertainties, via a unique Monte Carlo technique.

  9. Lunar surface heat flow mapping from radioactive elements measured by Lunar Prospector

    NASA Astrophysics Data System (ADS)

    Zhang, Dan; Li, Xiongyao; Li, Qingxia; Lang, Liang; Zheng, Yongchun

    2014-06-01

    An accurate estimate of global surface heat flow is important because it provides strong constraints on interior thermal model and understanding of the thermal state and geologic evolution of the Moon. In this paper, a distribution map of lunar surface heat flow is derived from calibrated Lunar Prospector gamma-ray spectrometer data (K, U and Th abundances). It shows that surface heat flow varies regionally from about 10.6 mW/m2 to 66.1 mW/m2, which is in the same order of magnitude as previous results. In the calculation, lunar surface heat flow includes the heat flow from the non-uniform distribution of radioactive elements K, U and Th and that from secular cooling of the Moon. The calculation of heat flow from radioactive elements is based on the assumption that the radioactive decay of K, U and Th on the Moon is the same as that on the Earth. The heat flow from secular cooling of the Moon is assumed to be equal to the global average radioactive heat flow. Firstly we construct a relationship between radioactive elements K, U and Th and lunar surface heat flow. The key parameter of the characteristic length scale in the relationship is determined by measured surface heat flow and Th abundances at Apollo 15 and 17 landing sites. Then the distribution of lunar surface heat flow is derived by combining other parameters such as lunar crustal thickness measured by Clementine and lunar crustal density. In addition, correlation analysis of the three radioactive elements is carried out due to the higher resolution of Th abundance and for ease of calculation.

  10. Chemical Studies of the Transactinide Elements at JAEA

    SciTech Connect

    Nagame, Y.; Asai, M.; Hirata, M.; Ishii, Y.; Nishinaka, I.; Tome, H.; Toyoshima, A.; Tsukada, K.; Akiyama, K.; Goto, S.; Haba, H.

    2006-11-02

    Chemical properties of the transactinide element, rutherfordium (Rf), produced in the reaction 248Cm(18O, 5n) have been studied based on an atom-at-a-time scale. Ion-exchange chromatographic experiments on Rf together with the lighter homologues in the periodic table of the elements, group-4 elements Zr and Hf, in hydrofluoric acid solutions have been conducted with a rapid chemical separation apparatus. From the systematic study of the anion-exchange behavior of Rf, we have observed unexpected chemical behavior of Rf; the fluoride complex formation of Rf is significantly different from those of the homologues. Characteristics of the complexing strength of the Rf fluoride are briefly discussed by comparing with those of the homologues and with theoretical predictions by relativistic molecular density-functional calculations.

  11. Method for disposing of radioactive graphite and silicon carbide in graphite fuel elements

    SciTech Connect

    Gay, R.L.

    1995-09-12

    Method is described for destroying radioactive graphite and silicon carbide in fuel elements containing small spheres of uranium oxide coated with silicon carbide in a graphite matrix, by treating the graphite fuel elements in a molten salt bath in the presence of air, the salt bath comprising molten sodium-based salts such as sodium carbonate and a small amount of sodium sulfate as catalyst, or calcium-based salts such as calcium chloride and a small amount of calcium sulfate as catalyst, while maintaining the salt bath in a temperature range of about 950 to about 1,100 C. As a further feature of the invention, large radioactive graphite fuel elements, e.g. of the above composition, can be processed to oxidize the graphite and silicon carbide, by introducing the fuel element into a reaction vessel having downwardly and inwardly sloping sides, the fuel element being of a size such that it is supported in the vessel at a point above the molten salt bath therein. Air is bubbled through the bath, causing it to expand and wash the bottom of the fuel element to cause reaction and destruction of the fuel element as it gradually disintegrates and falls into the molten bath. 4 figs.

  12. Chemical elements in organic and conventional sweet oranges.

    PubMed

    Turra, Christian; Fernandes, Elisabete A De Nadai; Bacchi, Márcio Arruda; Barbosa Júnior, Fernando; Sarriés, Gabriel Adrián; Blumer, Lucimara

    2011-12-01

    This work focuses on the determination of chemical elements in sweet oranges of variety Valencia produced under organic and conventional systems using instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. The distribution of chemical elements was variable among the fruit parts with usually higher concentrations of Br, Ca, Ce, K, La, Na, Rb, and Sc in the peel. However, K, Na, and Rb also presented high values in the juice samples, while Fe and Zn were higher in the seeds. Differences between organic and conventional oranges were found for Br and Cu. PMID:21735113

  13. Chemical Properties of Elements 99 and 100 [Einsteinium and Fermium

    DOE R&D Accomplishments Database

    Seaborg, G. T.; Thompson, S. G.; Harvey, B. G.; Choppin, G. R.

    1954-07-23

    A description of some of the chemical properties and of the methods used in the separations of elements 99 [Einsteinium] and 100 [Fermium] are given. The new elements exhibit the properties expected for the tenth and eleventh actinide elements. Attempts to produce an oxidation state greater than III of element 99 have been unsuccessful. In normal aqueous media only the III state of element 100 appears to exist. The relative spacings of the elution peaks of the new elements in some separations with ion exchange resin columns are the same as the relative spacings of the homologous lanthanide elements. The results of experiments involving cation exchange resins with very concentrated hydrochloric acid eluant show that the new elements, like the earlier actinides, are more strongly complexed than the lanthanides. The new elements also exist partially as anions in concentrated hydrochloric acid, as do earlier actinide elements, and they may be partially separated from each other by means of ion exchange resins. With some eluants interesting reversals of elution positions are observed in the region Bk-Cf-99-100, indicating complex ion formation involving unusual factors.

  14. Concentration of chemical elements by zooplankton of the White Sea

    NASA Astrophysics Data System (ADS)

    Leonova, G. A.; Bobrov, V. A.; Bogush, A. A.; Bychinskii, V. A.

    2013-02-01

    A technique of net sampling of zooplankton at night in the Kandalaksha and Dvinskii Bays and during the full tide in the Onezhskii Bay of the White Sea allowed us to obtain "clean" samples without considerable admixtures of terrigenous suspension. The absence of elements-indicators of the terrigenous suspension (Al, Ti, and Zr) in the EDX spectra allows concluding that the ash composition of the tested samples is defined by the constitutional elements comprising the organic matter and integument (chitin, shells) of planktonic organisms. A quantitative assessment of the accumulation of a large group of chemical elements (approximately 40) by zooplankton based on a complex of modern physical methods of analysis is presented. The values of the coefficient of the biological accumulation of the elements (Kb) calculated for the organic matter and the enrichment factors (EF) relative to the Clarke concentrations in the shale are in general determined by the mobility of the chemical elements in the aqueous solution, which is confirmed by the calculated chemical speciation of the elements in the inorganic subsystem of the surface waters of Onezhskii Bay.

  15. The System of Chemical Elements Distribution in the Hydrosphere

    NASA Astrophysics Data System (ADS)

    Korzh, Vyacheslav D.

    2013-04-01

    The chemical composition of the hydrosphere is a result of substance migration and transformation on lithosphere-river, river-sea, and ocean-atmosphere boundaries. The chemical elements composition of oceanic water is a fundamental multi-dimensional constant for our planet. Detailed studies revealed three types of chemical element distribution in the ocean: 1) Conservative: concentration normalized to salinity is the constant in space and time; 2) Nutrient-type: element concentration in the surface waters decreases due to the biosphere consumption; and 3) Litho-generative: complex character of distribution of elements, which enter the ocean with the river runoff and interred almost entirely in sediments. The correlation between the chemical elements compositions of the river and oceanic water is high (r = 0.94). We conclude that biogeochemical features of each chemical element are determined by the relationship between its average concentration in the ocean and the intensity of its migration through hydrosphere boundary zones. In our presentation, we shall show intensities of global migration and average concentrations in the ocean in the co ordinates lgC - lg [tau], where C is an average element concentration and [tau] is its residence time in the ocean. We have derived a relationship between three main geochemical parameters of the dissolved forms of chemical elements in the hydrosphere: 1) average concentration in the ocean, 2) average concentration in the river runoff and 3) the type of distribution in oceanic water. Using knowledge of two of these parameters, it allows gaining theoretical knowledge of the third. The System covers all chemical elements for the entire range of observed concentrations. It even allows to predict the values of the annual river transport of dissolved Be, C, N, Ge, Tl, Re, to refine such estimates for P, V, Zn, Br, I, and to determine the character of distribution in the ocean for Au and U. Furthermore, the System allowed estimating

  16. An Educational Card Game for Learning Families of Chemical Elements

    ERIC Educational Resources Information Center

    Mariscal, Antonio Joaquin Franco; Martinez, Jose Maria Oliva; Marquez, Serafin Bernal

    2012-01-01

    This paper describes an educational card game designed to help high school students (grade 10, 15-16 years old) "understand," as opposed to memorize, the periodic table. The game may also be used to identify different chemical elements found in daily life objects. As an additional value, students learn the names and symbols of the displayed…

  17. HISTORY OF THE ORIGIN OF THE CHEMICAL ELEMENTS AND THEIR DISCOVERIES.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

    The origin of the chemical elements show a wide diversity with some of these elements having their origin in antiquity. Still other elements have been synthesized within the past fifty years via nuclear reactions on heavy elements, because these other elements are unstable and radioactive and do not exist in nature. The names of the elements come from many sources including mythological concepts or characters; places, areas or countries; properties of the element or its compounds, such as color, smell or its inability to combine; and the names of scientists. There are also some miscellaneous names as well as some obscure names for particular elements. The claim of discovery of an element has varied over the centuries. Many claims, e.g., the discovery of certain rare earth elements of the lanthanide series, involved the discovery of a mineral ore from which an element was later extracted. The honor of discovery has often been accorded not to the person who first isolated the element but to the person who discovered the original mineral itself, even when the ore was impure and contained many elements. The reason for this is that in the case of these rare earth elements, the ''earth'' now refers to oxides of a metal not to the metal itself. This fact was not realized at the time of their discovery, until the English chemist Humphry Davy showed that earths were compounds of oxygen and metals in 1808. In the early discoveries, the atomic weight of an element and spectral analysis of the element were not available. Later both of these elemental properties would be required before discovery of the element would be accepted. In general, the requirements for discovery claims have tightened through the years and claims that were previously accepted would no longer meet the minimum constraints now imposed. There are cases where the honor of discovery is not given to the first person to actually discover the element but to the first person to claim the discovery in print. If a

  18. Prompt gamma neutron activation analysis of toxic elements in radioactive waste packages.

    PubMed

    Ma, J-L; Carasco, C; Perot, B; Mauerhofer, E; Kettler, J; Havenith, A

    2012-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R&D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages. In particular, the amount of toxic elements present in radioactive waste packages must be assessed before they can be accepted in repository facilities in order to avoid pollution of underground water reserves. To this aim, the Nuclear Measurement Laboratory of CEA-Cadarache has started to study the performances of Prompt Gamma Neutron Activation Analysis (PGNAA) for elements showing large capture cross sections such as mercury, cadmium, boron, and chromium. This paper reports a comparison between Monte Carlo calculations performed with the MCNPX computer code using the ENDF/B-VII.0 library and experimental gamma rays measured in the REGAIN PGNAA cell with small samples of nickel, lead, cadmium, arsenic, antimony, chromium, magnesium, zinc, boron, and lithium to verify the validity of a numerical model and gamma-ray production data. The measurement of a ∼20kg test sample of concrete containing toxic elements has also been performed, in collaboration with Forschungszentrum Jülich, to validate the model in view of future performance studies for dense and large LL-MA waste packages. PMID:22406218

  19. Survey of chemical speciation of trace elements using synchrotron radiation

    SciTech Connect

    Gordon, B.M.

    1985-01-01

    Information concerning the chemical state of trace elements in biological systems generally has not been available. Such information for toxic elements and metals in metalloproteins could prove extremely valuable in the elucidation of their metabolism and other biological processes. The shielding of core electrons by binding electrons affect the energy required for creating inner-shell holes. Furthermore, the molecular binding and the symmetry of the local environment of an atom affect the absorption spectrum in the neighborhood of the absorption edge. X-ray absorption near-edge structure (XANES) using synchrotron radiation excitation can be used to provide chemical speciation information for trace elements at concentrations as low as 10 ppM. The structure and position of the absorption curve in the region of an edge can yield vital data about the local structure and oxidation state of the trace element in question. Data are most easily interpreted by comparing the observed edge structure and position with those of model compounds of the element covering the entire range of possible oxidation states. Examples of such analyses are reviewed. 14 refs., 1 fig.

  20. Inhomogeneous chemical evolution of r-process elements

    NASA Astrophysics Data System (ADS)

    Wehmeyer, B.; Pignatari, M.; Thielemann, F.-K.

    2016-06-01

    We report the results of a galactic chemical evolution (GCE) study for r-process- and alpha elements. For this work, we used the inhomogeneous GCE model "ICE", which allows to keep track of the galactic abundances of elements produced by different astrophysical sites. The main input parameters for this study were: a) The Neutron Star Merger (NSM) coalescence time scale, the probability of NSMs, and for the sub-class of "magneto-rotationally driven Supernovae" ("Jet-SNe"), their occurence rate in comparison to "standard" Supernovae (SNe).

  1. Geothermal chemical elements in lichens of Yellowstone National Park

    USGS Publications Warehouse

    Bennett, J.P.; Wetmore, C.M.

    1999-01-01

    Geothermal features (e.g. geysers, fumaroles, vents, and springs) emit gaseous mercury, sulfur and heavy metals and therefore, are natural sources of these elements in the atmosphere. Field studies of heavy metals in lichens in Italy have detected elevated concentrations near geothermal power plants, and have determined that the origin of mercury is from soil degassing, not soil particles. We studied this phenomenon in a geothermal area without power plants to determine the natural levels of mercury and other elements. Two common and abundant species of epiphytic Lichens, Bryoria fremontii and Letharia vulpina, were collected at six localities in Yellowstone National Park, USA in 1998 and analyzed for 22 chemical elements. Thirteen elements differed significantly between species. Some elements were significantly higher in the southern part of the park, while others were higher in the north. Levels of most elements were comparable with those in other national parks and wilderness areas in the region, except Hg, which was unusually high. The most likely sources of this element are the geothermal features, which are known emitters of Hg. Multivariate analyses revealed strong positive associations of Hg with S, and negative associations with soil elements, providing strong evidence that the Hg in the lichens is the result of soil degassing of elemental Hg rather than particulate Hg directly from soils. Average Hg levels in the lichens were 140 p.p.b. in Bryoria and 110 p.p.b. in Letharia, but maxima were 291 and 243 p.p.b., respectively. In spite of this, both species were healthy and abundant throughout the park.

  2. Stellar alchemy: The origin of the chemical elements

    SciTech Connect

    Norman, E.B.

    1994-03-13

    What makes the stars shine? This question puzzled human beings for thousands of years. Early in this century, chemists and physicists discovered radioactivity; and the nuclear model of the atom was developed. Once nuclear reactions were produced in the laboratory, it did not take long before their role in stellar energy generation was realized. The theory that nuclear fusion is the source of stellar energy was initially developed in the 1930`s and was elaborated in detail in the 1950`s. Only within the last ten years, however, have astronomical observations provided direct confirmation of these theoretical ideas. In this paper, I describe the sequences of nuclear reactions that are believed to be responsible for the power generation in stars. The ashes of these reactions are the heavy elements that we find on earth and throughout the universe. The evolution and final fates of stars are examined. The key astronomical observations that provide support for these theoretical ideas are presented.

  3. Chemical and nuclear properties of lawrencium (element 103) and hahnium (element 105)

    SciTech Connect

    Henderson, R.A.

    1990-09-10

    The chemical and nuclear properties of Lr and Ha have been studied, using 3-minute {sup 260}Lr and 35-second {sup 262}Ha. The crystal ionic radius of Lr{sup 3+} was determined by comparing its elution position from a cation-exchange resin column with those of lanthanide elements having known ionic radii. Comparisons are made to the ionic radii of the heavy actinides, Am{sup 3+} through Es{sup 3+}, obtained by x-ray diffraction methods, and to Md{sup 3+} and Fm{sup 3+} which were determined in the same manner as Lr{sup 3+}. The hydration enthalpy of {minus}3622 kJ/mol was calculated from the crystal ionic radius using an empirical form of the Born equation. Comparisons to the spacings between the ionic radii of the heaviest members of the lanthanide series show that the 2Z spacing between Lr{sup 3+} and Md{sup 3+} is anomalously small, as the ionic radius of Lr{sup 3+} of 0.0886 nm is significantly smaller than had been expected. The chemical properties of Ha were determined relative to the lighter homologs in group 5, Nb and Ta. Group 4 and group 5 tracer activities, as well as Ha, were absorbed onto glass surfaces as a first step toward the determination of the chemical properties of Ha. Ha was found to adsorb on surfaces, a chemical property unique to the group 5 elements, and as such demonstrates that Ha has the chemical properties of a group 5 element. A solvent extraction procedure was adapted for use as a micro-scale chemical procedure to examine whether or not Ha displays eka-Ta-like chemical under conditions where Ta will be extracted into the organic phase and Nb will not. Under the conditions of this experiment Ha did not extract, and does not show eka-Ta-like chemical properties.

  4. The Chemical Evolution of Heavy Elements in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Shingles, Luke J.; Karakas, Amanda I.; Hirschi, Raphael

    2014-01-01

    We present preliminary results from a chemical evolution model that tracks the composition of heavy elements beyond iron in a globular cluster. The heavy elements can be used as tracers of the nucleosynthetic events that defined the formation and evolution of star clusters in the early Universe. In particular, the chemical evolution model focuses on the hypothesis that rapidly-rotating massive stars produced the heavy elements via the slow neutron-capture process and seeded the proto-cluster while the stars we see today were still forming. We compare our model with heavy element abundances in M4 and M5, and M22. Our results are strongly dependent on the highly uncertain rate of the 17O(α,γ)21Ne reaction, which determines the strength of 16O as a neutron poison. We find that the [Pb/Ba] ratio is too low to match the empirical value, which might suggest that a contribution from AGB stars is required.

  5. Radioactive Fission Product Release from Defective Light Water Reactor Fuel Elements

    SciTech Connect

    Konyashov, Vadim V.; Krasnov, Alexander M.

    2002-04-15

    Results are provided of the experimental investigation of radioactive fission product (RFP) release, i.e., krypton, xenon, and iodine radionuclides from fuel elements with initial defects during long-term (3 to 5 yr) irradiation under low linear power (5 to 12 kW/m) and during special experiments in the VK-50 vessel-type boiling water reactor.The calculation model for the RFP release from the fuel-to-cladding gap of the defective fuel element into coolant was developed. It takes into account the convective transport in the fuel-to-cladding gap and RFP sorption on the internal cladding surface and is in good agreement with the available experimental data. An approximate analytical solution of the transport equation is given. The calculation dependencies of the RFP release coefficients on the main parameters such as defect size, fuel-to-cladding gap, temperature of the internal cladding surface, and radioactive decay constant were analyzed.It is shown that the change of the RFP release from the fuel elements with the initial defects during long-term irradiation is, mainly, caused by fuel swelling followed by reduction of the fuel-to-cladding gap and the fuel temperature. The calculation model for the RFP release from defective fuel elements applicable to light water reactors (LWRs) was developed. It takes into account the change of the defective fuel element parameters during long-term irradiation. The calculation error according to the program does not exceed 30% over all the linear power change range of the LWR fuel elements (from 5 to 26 kW/m)

  6. Guidelines for generators of hazardous chemical waste at LBL and Guidelines for generators of radioactive and mixed waste at LBL

    SciTech Connect

    Not Available

    1991-07-01

    The purpose of this document is to provide the acceptance criteria for the transfer of hazardous chemical, radioactive, and mixed waste to Lawrence Berkeley Laboratory's (LBL) Hazardous Waste Handling Facility (HWHF). These guidelines describe how a generator of wastes can meet LBL's acceptance criteria for hazardous chemical, radioactive, and mixed waste. 9 figs.

  7. Radioactive elements on Mercury's surface from MESSENGER: implications for the planet's formation and evolution.

    PubMed

    Peplowski, Patrick N; Evans, Larry G; Hauck, Steven A; McCoy, Timothy J; Boynton, William V; Gillis-Davis, Jeffery J; Ebel, Denton S; Goldsten, John O; Hamara, David K; Lawrence, David J; McNutt, Ralph L; Nittler, Larry R; Solomon, Sean C; Rhodes, Edgar A; Sprague, Ann L; Starr, Richard D; Stockstill-Cahill, Karen R

    2011-09-30

    The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury's northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury's formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.8 billion years ago and limited, isolated volcanic activity since. PMID:21960624

  8. Elemental characterization of LL-MA radioactive waste packages with the associated particle technique

    SciTech Connect

    Perot, B.; Carasco, C.; Toure, M.; El Kanawati, W.; Eleon, C.

    2011-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R and D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages with analytical methods and with non-destructive nuclear measurements. This paper concerns fast neutron interrogation with the associated particle technique (APT), which brings 3D information about the waste material composition. The characterization of volume elements filled with iron, water, aluminium, and PVC in bituminized and fibre concrete LL-MA waste packages has been investigated with MCNP [1] and MODAR data analysis software [2]. APT provides usable information about major elements presents in the volumes of interest. However, neutron scattering on hydrogen nuclei spreads the tagged neutron beam out of the targeted volume towards surrounding materials, reducing spatial selectivity. Simulation shows that small less than 1 L targets can be characterised up to the half-radius of a 225 L bituminized drum, the matrix of which is very rich in hydrogen. Deeper characterization in concrete is possible but limited by counting statistics due to photon attenuation in this dense matrix and, unless large inspection volumes are considered, by the lack of spatial selectivity of the tagged neutron beam due to neutron scattering. (authors)

  9. Chemical and nuclear properties of Rutherfordium (Element 104)

    SciTech Connect

    Kacher, C.D.

    1995-10-30

    The chemical-properties of rutherfordium (Rf) and its group 4 homologs were studied by sorption on glass support surfaces coated with cobalt(II)ferrocyanide and by solvent extraction with tributylphosphate (TBP) and triisooctylamine (TIOA). The surface studies showed that the hydrolysis trend in the group 4 elements and the pseudogroup 4 element, lb, decreases in the order Rf>Zr{approx}Hf>Th. This trend was attributed to relativistic effects which predicted that Rf would be more prone to having a coordination number of 6 than 8 in most aqueous solutions due to a destabilization of the 6d{sub 5/2} shell and a stabilization of the 7p{sub l/2} shell. This hydrolysis trend was confirmed in the TBP/HBr solvent extraction studies which showed that the extraction trend decreased in the order Zr>Hf>Rf?Ti for HBr, showing that Rf and Ti did not extract as well because they hydrolyzed more easily than Zr and Hf. The TIOA/HF solvent extraction studies showed that the extraction trend for the group 4 elements decreased in the order Ti>Zr{approx}Hf>Rf, in inverse order from the trend of ionic radii Rf>Zr{approx}Hf>Ti. An attempt was made to produce {sup 263}Rf (a) via the {sup 248}Cm({sup 22}Ne, {alpha}3n) reaction employing thenoyltrifluoroacetone (TTA) solvent extraction chemistry and (b) via the {sup 249}Bk({sup 18}O,4n) reaction employing the Automated Rapid Chemistry Apparatus (ARCA). In the TTA studies, 16 fissions were observed but were all attributed to {sup 256}Fm. No alpha events were observed in the Rf chemical fraction. A 0.2 nb upper limit production cross section for the {sup 248}Cm({sup 22}Ne, {alpha}3n){sup 263}Rf reaction was calculated assuming the 500-sec half-life reported previously by Czerwinski et al. [CZE92A].

  10. Stellar alchemy: The origin of the chemical elements

    SciTech Connect

    Norman, E.B. . Nuclear Science Div.)

    1994-10-01

    By examining the light that comes from the stars, one can deduce a great deal about the nature of the universe. Remarkably, it seems that the same basic laws of physics and chemistry apply everywhere. Furthermore, all observable astronomical objects seem to be made up of the same 92 chemical elements found on Earth. From such observations, we now know that approximately 73% of the mass of the visible universe is in the form of hydrogen, and helium makes up about 25%. Everything else represents only 2% of the mass of the universe. Although the abundance of these heavy (A > 4) elements seems quite low, most of the atoms in our bodies and in the Earth are a part of this small portion. It is generally believed that the hydrogen and helium were produced in the hot, dense conditions prevailing at the birth of the universe known as the big bang. As discussed in the article the heavy elements are the products of nuclear reactions in stars.

  11. Interactions between concentrations of chemical elements in human femoral heads.

    PubMed

    Brodziak-Dopierala, Barbara; Kwapulinski, Jerzy; Kusz, Damian; Gajda, Zbigniew; Sobczyk, Krzysztof

    2009-07-01

    Environmental and occupational exposure to various metals has been a major public health concern and the subject of many studies. With the development of industry and transportation, environmental pollution has markedly worsened. As a result, metals are now ubiquitous and are absorbed into the body with food, drinking water, and polluted air. Exposure to these elements leads to numerous health problems, affecting almost every system of the human body, including the skeletal system. Bone is a specific research material that is difficult to obtain, therefore chemical analyses of metal concentrations in this tissue are rarely found in the literature. Nevertheless, bone, due to its long regeneration period, can serve as a biomarker of a long-term metal accumulation resulting from environmental or occupational exposure. Our study was conducted on bone samples harvested from inhabitants of the Upper Silesia region during hip replacement surgery. Femoral heads removed during surgery were sectioned into slices and further subdivided into samples comprising articular cartilage, cortical bone, and trabecular bone. Concentrations of 12 trace elements were measured with an atomic absorption spectrophotometry method. We found significant correlation between concentrations of these metal elements in the samples of cortical bone. This is determined not only by the physiological functions of these metals in hydroxyapatite, but also by the specific mineral structure of the bone tissue. PMID:18776997

  12. Lab Astro and the Origins of the Chemical Elements

    NASA Astrophysics Data System (ADS)

    Lawler, James E.

    2010-03-01

    Interpretation of the spectra of metal-poor Galactic halo stars is dependent on AMO laboratory data [1,2]. Metal-poor Galactic halo stars were born when the Milky Way was young and they provide a record of the chemical evolution of the Galaxy. Elements heavier than iron are produced via r(apid)-process and s(low)-process n(eutron)-capture mechanisms. The s-process mechanism, which occurs in certain AGB stars, is relatively well understood. The explosive r-process is not well understood. The r-process n-capture mechanism was dominant early in the Galaxy's history [3]. New large aperture telescopes make it possible to record high-resolution spectra with high signal-to-noise ratios on a growing number of metal-poor stars. In addition to mapping the chemical evolution of the Galaxy, these studies are yielding an increasingly well-defined r-process elemental abundance pattern which constrains models of r-process nucleosynthesis [1]. The next phase of this ongoing research will address challenges in modeling stellar photospheres. Peculiar trends in abundances of specific Fe-group elements as a function of stellar age or metallicity may be due to limitations in traditional one dimensional (1d) local thermodynamic equilibrium (LTE) models of stellar photospheres or may be due to poorly understood nucleosynthesis [4]. Efforts are now underway to test the Saha or ionization equilibrium in a variety of stellar atmospheres for several Fe-group elements using the best available spectroscopic data for selected transitions. More comprehensive spectroscopic data of improved accuracy and accurate collisional data, especially for inelastic collisions of H atoms with metal atoms and ions, will be needed to fully develop 3d/non-LTE models of photospheres [e.g. 5]. [4pt] [1] C. Sneden, J. E. Lawler, J. J. Cowan, I. I. Ivans, and E. A. Den Hartog, Astrophys. J. Suppl. Ser. 182, 80-96 (2009). [0pt] [2] J. E. Lawler, C. Sneden, J. J. Cowan, I. I. Ivans, and E. A. Den Hartog, Astrophys. J

  13. Metal complexes containing natural and and artificial radioactive elements and their applications.

    PubMed

    Kharissova, Oxana V; Méndez-Rojas, Miguel A; Kharisov, Boris I; Méndez, Ubaldo Ortiz; Martínez, Perla Elizondo

    2014-01-01

    Recent advances (during the 2007-2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well π-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m ((99m)Tc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described. PMID:25061724

  14. Natural radioactivity and rare earth elements in feldspar samples, Central Eastern desert, Egypt.

    PubMed

    Walley El-Dine, Nadia; El-Shershaby, Amal; Afifi, Sofia; Sroor, Amany; Samir, Eman

    2011-05-01

    The pegmatite bodies of the Eastern Desert of Egypt are widely distributed especially along the Marsa-Alam-Idfu road. The Abu Dob area covers about 150km(2) of the Arabian Nubian shield at the central part of the Eastern Desert of Egypt. Most of the pegmatite is zoned; the zonation starts with milky quartz at the core followed by alkali feldspar at the margins. The feldspars vary in color from rose to milky and in composition from K-feldspar to Na-feldspar, sometimes interactions of both types are encountered. Thirteen feldspar samples were collected from different locations in the Abu Dob area for measuring the natural radioactivity of (238)U, (232)Th and (40)K using an HPGe detector. The variation in concentration of radionuclides for the area under investigation can be classified into regions of high, medium and low natural radioactivity. The average concentration in BqKg(-1) has been observed to be from 9.5 to 183675.7BqKg(-1) for (238)U, between 6.1 and 94,314.2BqKg(-1) for (232)Th and from 0 to 7894.6BqKg(-1) for (40)K. Radium equivalent activities (Ra(eq)), dose rate (D(R)) and external hazard (H(ex)) have also been determined. In the present work, the concentration of rare earth elements are measured for two feldspar samples using two techniques, Environmental Scanning Electron microscope XIL 30 ESEM, Philips, and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The existence of rare earth elements in this area are very high and can be used in different important industries. PMID:21324705

  15. EDXRF quantitative analysis of chromophore chemical elements in corundum samples.

    PubMed

    Bonizzoni, L; Galli, A; Spinolo, G; Palanza, V

    2009-12-01

    Corundum is a crystalline form of aluminum oxide (Al(2)O(3)) and is one of the rock-forming minerals. When aluminum oxide is pure, the mineral is colorless, but the presence of trace amounts of other elements such as iron, titanium, and chromium in the crystal lattice gives the typical colors (including blue, red, violet, pink, green, yellow, orange, gray, white, colorless, and black) of gemstone varieties. The starting point for our work is the quantitative evaluation of the concentration of chromophore chemical elements with a precision as good as possible to match the data obtained by different techniques as such as optical absorption photoluminescence. The aim is to give an interpretation of the absorption bands present in the NIR and visible ranges which do not involve intervalence charge transfer transitions (Fe(2+) --> Fe(3+) and Fe(2+) --> Ti(4+)), commonly considered responsible of the important features of the blue sapphire absorption spectra. So, we developed a method to evaluate as accurately as possible the autoabsorption effects and the secondary excitation effects which frequently are sources of relevant errors in the quantitative EDXRF analysis. PMID:19821113

  16. Radioactivity, granulometric and elemental analysis of river sediments samples from the coast of Calabria, south of Italy

    NASA Astrophysics Data System (ADS)

    Caridi, F.; D'Agostino, M.; Marguccio, S.; Belvedere, A.; Belmusto, G.; Marcianò, G.; Sabatino, G.; Mottese, A.

    2016-05-01

    River sediment samples from different sites of the coast of Calabria, south of Italy, were analyzed to determine the natural radioactivity concentration of the studied area and to investigate about their geological provenience. The radioactivity investigation was performed by using HPGe gamma spectrometry. Activity concentration data were reported and the influence of the particle size on the radionuclides concentration was investigated. X-ray fluorescence spectrometry (XRF) measurements were performed for the quantitative elemental analysis of the river sediments, revealing the major and minor elements present in the investigated samples. From XRF experimental results it was possible to estimate the geological provenience of the analyzed river sediments. Data obtained in this article provide useful information on the background radioactivity of the studied area and can be further used for radiological mapping of the coast of the Calabria rivers.

  17. Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

    SciTech Connect

    Eppler, F.H.; Yim, M.S.

    1998-09-01

    Vitrification has been identified as one of the most viable waste treatment alternatives for nuclear waste disposal. Currently, the most popular glass compositions being selected for vitrification are the borosilicate family of glasses. Another popular type that has been around in glass industry is the soda-lime-silicate variety, which has often been characterized as the least durable and a poor candidate for radioactive waste vitrification. By replacing the boron constituent with a cheaper substitute, such as silica, the cost of vitrification processing can be reduced. At the same time, addition of network intermediates such as Al{sub 2}O{sub 3} to the glass composition increases the environmental durability of the glass. The objective of this study is to examine the ability of the soda-lime-aluminosilicate glass as an alternative vitrification tool for the disposal of radioactive waste and to investigate the sensitivity of product chemical durability to variations in composition.

  18. The chemical behavior of the transuranic elements and the barrier function in natural aquifer systems

    SciTech Connect

    Jewett, J.R.

    1997-09-17

    In a geological repository for long-lived radioactive wastes, such as actinides and certain fission products, most of the stored radionuclides remain immobile in the particular geological formation. If any of these could possibly become mobile, only trace concentrations of a few radionuclides would result. Nevertheless, with an inventory in the repository of many tonnes of transuranic elements, the amounts that could disperse cannot be neglected. A critical assessment of the chemical behavior of these nuclides, especially their migration properties in the aquifer system around the repository site, is mandatory for analysis of the long-term safety. The chemistry requited for this includes many geochemical multicomponent reactions that are so far only partially understood and [which] therefore can be quantified only incompletely. A few of these reactions have been discussed in this paper based on present knowledge. If a comprehensive discussion of the subject is impossible because of this [lack of information], then an attempt to emphasize the importance of the predominant geochemical reactions of the transuranic elements in various aquifer systems should be made.

  19. Detection of uranium and chemical state analysis of individual radioactive microparticles emitted from the Fukushima nuclear accident using multiple synchrotron radiation X-ray analyses.

    PubMed

    Abe, Yoshinari; Iizawa, Yushin; Terada, Yasuko; Adachi, Kouji; Igarashi, Yasuhito; Nakai, Izumi

    2014-09-01

    Synchrotron radiation (SR) X-ray microbeam analyses revealed the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, resulting in better understanding of what occurred in the plant during the early stages of the accident. Three spherical microparticles (∼2 μm, diameter) containing radioactive Cs were found in aerosol samples collected on March 14th and 15th, 2011, in Tsukuba, 172 km southwest of the FDNPP. SR-μ-X-ray fluorescence analysis detected the following 10 heavy elements in all three particles: Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba. In addition, U was found for the first time in two of the particles, further confirmed by U L-edge X-ray absorption near-edge structure (XANES) spectra, implying that U fuel and its fission products were contained in these particles along with radioactive Cs. These results strongly suggest that the FDNPP was damaged sufficiently to emit U fuel and fission products outside the containment vessel as aerosol particles. SR-μ-XANES spectra of Fe, Zn, Mo, and Sn K-edges for the individual particles revealed that they were present at high oxidation states, i.e., Fe(3+), Zn(2+), Mo(6+), and Sn(4+) in the glass matrix, confirmed by SR-μ-X-ray diffraction analysis. These radioactive materials in a glassy state may remain in the environment longer than those emitted as water-soluble radioactive Cs aerosol particles. PMID:25084242

  20. 3D Chemical and Elemental Imaging by STXM Spectrotomography

    SciTech Connect

    Wang, J.; Karunakaran, C.; Lu, Y.; Hormes, J.; Hitchcock, A. P.; Prange, A.; Franz, B.; Harkness, T.; Obst, M.

    2011-09-09

    Spectrotomography based on the scanning transmission x-ray microscope (STXM) at the 10ID-1 spectromicroscopy beamline of the Canadian Light Source was used to study two selected unicellular microorganisms. Spatial distributions of sulphur globules, calcium, protein, and polysaccharide in sulphur-metabolizing bacteria (Allochromatium vinosum) were determined at the S 2p, C 1s, and Ca 2p edges. 3D chemical mapping showed that the sulphur globules are located inside the bacteria with a strong spatial correlation with calcium ions (it is most probably calcium carbonate from the medium; however, with STXM the distribution and localization in the cell can be made visible, which is very interesting for a biologist) and polysaccharide-rich polymers, suggesting an influence of the organic components on the formation of the sulphur and calcium deposits. A second study investigated copper accumulating in yeast cells (Saccharomyces cerevisiae) treated with copper sulphate. 3D elemental imaging at the Cu 2p edge showed that Cu(II) is reduced to Cu(I) on the yeast cell wall. A novel needle-like wet cell sample holder for STXM spectrotomography studies of fully hydrated samples is discussed.

  1. Studies towards the development of chemically synthesized non-radioactive biotinylated nucleic acid hybridization probes.

    PubMed Central

    Al-Hakim, A H; Hull, R

    1986-01-01

    Non-radioactive nucleic acid hybridization probes have been constructed in which the reporter group is long chain biotin chemically linked to a basic macromolecule (histone H1, cytochrome C or polyethyleneimine). The modified basic macromolecule which carries many biotin residues can, in turn, be covalently linked to nucleic acids (DNA) via the bifunctional cross-linking reagents, glutaraldehyde, 1,2,7,8-diepoxyoctane, bis (succinimidyl) suberate or bis (sulfonosuccinimidyl) suberate. This provides a very sensitive probe by which as little as between 10-50fg of target DNA can be visualized using dot-blot hybridization procedures in conjunction with avidin or streptavidin enzyme conjugates. PMID:3027670

  2. Migration and Retardation of Chemical Toxic Components from Radioactive Waste - Hydrochemical Aspects

    SciTech Connect

    Jedinakova-Krizova, V.; Hanslik, E.

    2003-02-24

    A systematic analysis of nuclear power plant (NPP) operation and radioactive wastes disposal (near-surface disposal and geologic disposal) in underground repositories has provided the basis for a comparison between the radiotoxicity and chemotoxicity as part of an EIA (environmental impact assessment) procedure. This contribution summarizes the hydrochemical mechanisms of transport and retardation processes, chemistry and migration behavior of radionuclides and chemical toxics in natural sorbents, especially bentonites. The effect of solubility and dissolution reactions, diffusion and sorption/desorption, complexation and variations in the aqueous phase composition, pH-value and oxidation-reduction properties and other phenomena affecting distribution coefficients (Kd values) is discussed.

  3. Matching Element Symbols with State Abbreviations: A Fun Activity for Browsing the Periodic Table of Chemical Elements

    ERIC Educational Resources Information Center

    Woelk, Klaus

    2009-01-01

    A classroom activity is presented in which students are challenged to find matches between the United States two-letter postal abbreviations for states and chemical element symbols. The activity aims to lessen negative apprehensions students might have when the periodic table of the elements with its more than 100 combinations of letters is first…

  4. Calculations of the moon's heat history at different concentrations of radioactive elements taking account of the material differentiation with melting

    NASA Technical Reports Server (NTRS)

    Arnatskaya, O. I.; Alber, Y. I.; Ryazantseva, I. L.

    1974-01-01

    A mathematical procedure for analyzing the heat conductivity of the lunar surface is discussed. The solution is based on homogeneous and laminated moon models and considers the effects of radioactive elements conveyed to the lunar surface by melting. The various parameters which introduce uncertainties into the numerical analysis are identified. The application of data obtained from radio astronomy and from analyses of lunar samples returned by the Apollo flights is explained. Tables of data are included to show the types and amounts of radioactive materials which have been identified.

  5. Physical-chemical studies of transuranium elements: Progress report for the period April 1, 1985-March 31, 1988

    SciTech Connect

    Peterson, J.R.

    1987-01-01

    New knowledge is being accumulated in the role of the 5f electrons in the bonding in actinide elements and compounds, the relationships of metallic structures to metallic valence and radius, the extent and magnitude of the actinide contraction, the magnetic, thermodynamic, spectroscopic, and crystallographic properties of these materials as related to general theories, the effect of self-irradiation on chemical and physical properties, the chemical and physical consequences of radioactive decay in the bulk-phase solid state, and in general, the range of validity of the actinide hypothesis. Separate reports are given on: spectrophotometric studies of Cf(III) ions in lanthanide trihalide hosts, new ternary transplutonium chalcogenide halides, Raman spectrometric studies of lanthanide trihalides as function of T or P, and solution calorimetry of californium halides.

  6. Guidelines for generators of hazardous chemical waste at LBL and guidelines for generators of radioactive and mixed waste at LBL

    SciTech Connect

    Not Available

    1991-09-01

    In part one of this document the Governing Documents and Definitions sections provide general guidelines and regulations applying to the handling of hazardous chemical wastes. The remaining sections provide details on how you can prepare your waste properly for transport and disposal. They are correlated with the steps you must take to properly prepare your waste for pickup. The purpose of the second part of this document is to provide the acceptance criteria for the transfer of radioactive and mixed waste to LBL's Hazardous Waste Handling Facility (HWHF). These guidelines describe how you, as a generator of radioactive or mixed waste, can meet LBL's acceptance criteria for radioactive and mixed waste.

  7. Theoretical chemistry for chemical identification of the heaviest elements

    NASA Astrophysics Data System (ADS)

    Pershina, V.; Bastug, T.; Anton, J.; Fricke, B.

    2007-05-01

    Adsorption of element 112 on various types of surfaces was studied on the basis of fully relativistic four-component Density-Functional Theory (DFT) electronic structure calculations for atoms, dimers and atom-cluster systems. Using models of localized and mobile adsorption, the equilibrium adsorption temperature for element 112 is predicted with respect to that of Hg on quartz and gold surfaces. On quartz, element 112 should be stronger adsorbed than Hg by about 5 kJ/mol (or by 5 degrees higher temperatures) due to the stronger van der Walls interaction. This is caused by the relativistically contracted smallest atomic radius of element 112. On surface of gold, element 112 should be weaker adsorbed than Hg by about 20 kJ/mol, i.e., at about 100 degrees lower temperatures than Hg. The predicted similarity to Hg indicates that element 112 should be a transition metal forming intermetallic compounds with Au and other metals due to the relatively large involvement of the relativistically destabilized 6d orbitals in bonding. The difference in adsorption enthalpy between Hg and element 112 depends, however, on the adsorption position.

  8. EXPLORING ENGINEERING CONTROL THROUGH PROCESS MANIPULATION OF RADIOACTIVE LIQUID WASTE TANK CHEMICAL CLEANING

    SciTech Connect

    Brown, A.

    2014-04-27

    One method of remediating legacy liquid radioactive waste produced during the cold war, is aggressive in-tank chemical cleaning. Chemical cleaning has successfully reduced the curie content of residual waste heels in large underground storage tanks; however this process generates significant chemical hazards. Mercury is often the bounding hazard due to its extensive use in the separations process that produced the waste. This paper explores how variations in controllable process factors, tank level and temperature, may be manipulated to reduce the hazard potential related to mercury vapor generation. When compared using a multivariate regression analysis, findings indicated that there was a significant relationship between both tank level (p value of 1.65x10{sup -23}) and temperature (p value of 6.39x10{sup -6}) to the mercury vapor concentration in the tank ventilation system. Tank temperature showed the most promise as a controllable parameter for future tank cleaning endeavors. Despite statistically significant relationships, there may not be confidence in the ability to control accident scenarios to below mercury’s IDLH or PAC-III levels for future cleaning initiatives.

  9. Chemical weathering of monsoonal eastern China: implications from major elements of topsoil

    NASA Astrophysics Data System (ADS)

    Qiu, Shifan; Zhu, Zhaoyu; Yang, Tian; Wu, Yi; Bai, Yang; Ouyang, Tingping

    2014-02-01

    Major element compositions of 36 bulk samples and 41 clay samples, which were obtained from 47 topsoils collected in monsoonal eastern China, were investigated with conventional wet chemistry and X-ray fluorescence (XRF) spectrometry, respectively. Based on major element analyses, the mobility of major elements and latitudinal distributions of SiO2/Al2O3 ratio, chemical index of alteration (CIA), chemical index of weathering (CIW) and weathering index of Parker (WIP) were analyzed. Meanwhile, the suitability of these chemical weathering indices to topsoils in monsoonal eastern China and its controls were discussed.

  10. RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

    SciTech Connect

    Salas, H.T.; Nalini, H.A. Jr.; Mendes, J.C.

    2004-10-03

    One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples with total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.

  11. Aerosol chemical elemental mass concentration at lower free troposphere

    NASA Astrophysics Data System (ADS)

    do Carmo Freitas, Maria; Dionísio, Isabel; Fialho, Paulo; Barata, Filipe

    2007-08-01

    This paper shows the use of Instrumental neutron activation analysis (INAA) technique to determine elemental masses collected by a seven-wavelength Aethalometer instrument at the summit of Pico mountain in the Azorean archipelago, situated in the Central North Atlantic Ocean. Each sample corresponds to air particulate matter measured continuously for periods of approximately 24 h taken from 14th July 2001 through 14th July 2002. The statistical analysis of the coefficients of correlation between all the elements identified, permitted to establish six groups that could potentially be associated with the type of source responsible for the aerosol sampled in the lower free troposphere at the Azorean archipelago. Calculation of the synoptic back trajectories helped to corroborate the use of the iron/cesium relation as a tracer for the Saharan dust aerosol. It was demonstrated that INAA constituted an important tool to identify these events.

  12. Major element chemical compositions of chondrules in unequilibrated chondrites

    NASA Technical Reports Server (NTRS)

    Ikeda, Y.

    1984-01-01

    The chemical compositions (except for metals and sulfides in chondrules) of more than 500 chondrules from unequilibrated E, H, L, LL, and C chondrites were measured using a broad beam of an electron-probe microanalyzer. The compositions of chondrules can be represented by various mixtures of normative compositions of olivine, low-Ca pyroxene, plagioclase, and high-Ca pyroxene with minor amounts of spinel, feldspathoid, SiO2-minerals, etc., indicating that the chondrule precursor materials consisted of aggregates of these minerals. The Al, Na, and K contents of most chondrules reflect the compositions of the ternary feldspar (An-Ab-Kf) of the chondrule precursor materials, and chemical types of chondrules (KF, SP, IP, and CP) are defined on the basis of the atomic proportion of Al, Na, and K.

  13. Advanced Theoretical Studies for Chemical Identification of the Heaviest Elements

    NASA Astrophysics Data System (ADS)

    Pershina, V.

    2015-06-01

    Both relativistic Dirac-Fock (DF) correlated, CCSD(T), and the density-functional theory (DFT) methods with various GGA exchange-correlation potentials agree on an increase in the M-Au bond strength from M = Cn to Fl. This means that the adsorption energy of Fl on gold, as measured by gas-phase chromatography experiments, must be larger for Fl than for Cn. For the weak (van der Waals) interactions, the trend to an increase in bonding from Cn2 to Fl2 obtained at the DFT level of theory is also confirmed by the DF CCSD(T) calculations. Thus, for comparative studies, relativistic DFT is a very reliable and efficient tool. First calculations of adsorption of TlOH and element 113OH on a hydroxylated quartz surface are reported.

  14. Virtual Laboratory as an Element of Visualization When Teaching Chemical Contents in Science Class

    ERIC Educational Resources Information Center

    Herga, Nataša Rizman; Grmek, Milena Ivanuš; Dinevski, Dejan

    2014-01-01

    Using a variety of visualization tools for teaching and learning science and chemistry is necessary because pupils better understand chemical phenomena and formulate appropriate mental models. The purpose of the presented study was to determine the importance of a virtual laboratory as a visualization element when addressing chemical contents…

  15. Chemical and elemental comparison of two formulations of oleoresin capsicum.

    PubMed

    Haas, J S; Whipple, R E; Grant, P M; Andresen, B D; Volpe, A M; Pelkey, G E

    1997-01-01

    In-custody deaths following the application of pepper spray weaponry by law enforcement personnel have increased in California over the last few years. Oleoresin capsicum (OC), an oily extract of hot peppers, is the active ingredient in the spray, but little detailed information on product mixtures is available. Since OC extracts contain a multitude of natural compounds at irregular concentrations, there could be considerable, variation in overall chemical composition among the different formulations of both 'natural' and 'synthetic' OC preparations. This was confirmed by organic and inorganic analyses performed on OC sprays produced by two manufacturers licensed for distribution within the state of California. The results indicated that the differences could lead to considerable inconsistency in weapon effectiveness, and suggested that more comprehensive studies are warranted. PMID:9022856

  16. Risk assessment for chemical pickling of metals contaminated by radioactive materials.

    PubMed

    Donzella, A; Formisano, P; Giroletti, E; Zenoni, A

    2007-01-01

    In recent years, many cases of contamination of metal scraps by unwanted radioactive materials have occurred. Moreover, international organisations are evaluating the possibility to re-use or to recycle metals coming from nuclear power plants. The metal recycling industry has started to worry about radiation exposure of workers that could be in contact with contaminated metals during each manufacturing phase. Risks are strongly dependent on the radiation source features. The aim of this study is to perform risk assessment for workers involved in chemical pickling of steel coils. Monte Carlo simulations have been performed, using the MCNP package and considering coils contaminated with (60)Co, (137)Cs, (241)Am and (226)Ra. Under the most conservative conditions (coil contaminated with 1.0 kBq g(-1) of (60)Co), the dose assessment results lower than the European dose limit for the population (1 mSv y(-1)), considering a maximum number of 10 contaminated coils handled per year. The only exception concerns the case of (241)Am, for which internal contamination could be non- negligible and should be verified in the specific cases. In every case, radiation exposure risk for people standing at 50 m from the coil is widely <1 mSv y(-1). PMID:16849378

  17. Chemical and radioactive composition of bulk deposition in Málaga (Spain)

    NASA Astrophysics Data System (ADS)

    Dueñas, C.; Fernández, M. C.; Gordo, E.; Cañete, S.; Pérez, M.

    2012-12-01

    Chemical and radioactive composition of bulk deposition samples, which were collected monthly over a 5 year period (January 2007 until 31 December 2011) at a site located 30 m.a.l. in Málaga (4°28‧ 8″W; 36°43‧ 40″N) have been analysed. All samples were analysed for pH, major ions and gamma radionuclides. The average pH of bulk deposition was 6.4. Cl- and SO were the main anions, while Ca+ and Na+ were the main cations. Significant correlations were found in soil-derived species among Ca2+, Mg2+ and K+ and sea-salt species between Na+ and Cl-. Other relatively good correlations were also observed between acidic anions (SOandNO) and crustal-derived cations (Ca2+, Na+, K+). Sources of the major ions were assessed based on the enrichment factor method. The radionuclides present in all samples are 7Be and 210Pb and 40K appears in 50% of the samples. Relatively poor correlations were observed between the specific activities of gamma radionuclides and the major ions. The temporal variations of major ions and radionuclides exhibit similar seasonal behaviour with low values in winter-autumn months and maximum values in spring-summer months. The fluxes of major ions and gamma radionuclides have been discussed with meteorological factors controlling depositions.

  18. Radioactive Elements on Mercury’s Surface from MESSENGER: Implications for the Planet’s Formation and Evolution

    NASA Astrophysics Data System (ADS)

    Peplowski, Patrick N.; Evans, Larry G.; Hauck, Steven A.; McCoy, Timothy J.; Boynton, William V.; Gillis-Davis, Jeffery J.; Ebel, Denton S.; Goldsten, John O.; Hamara, David K.; Lawrence, David J.; McNutt, Ralph L.; Nittler, Larry R.; Solomon, Sean C.; Rhodes, Edgar A.; Sprague, Ann L.; Starr, Richard D.; Stockstill-Cahill, Karen R.

    2011-09-01

    The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury’s northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury’s formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.8 billion years ago and limited, isolated volcanic activity since.

  19. Chemical studies of elements with Z ≥ 104 in liquid phase

    NASA Astrophysics Data System (ADS)

    Nagame, Yuichiro; Kratz, Jens Volker; Schädel, Matthias

    2015-12-01

    Recent studies of the chemical separation and characterization experiments of the first three transactinide elements, rutherfordium (Rf), dubnium (Db), and seaborgium (Sg), conducted atom-at-a-time in liquid phases, are reviewed. A short description on experimental techniques based on partition methods, specifically automated rapid chemical separation systems, is also given. A newly developed experimental approach to investigate single atoms of the heaviest elements with an electrochemical method is introduced. Perspectives for liquid-phase chemistry experiments on heavier elements are briefly discussed.

  20. Integrated Numerical Simulation of Thermo-Hydro-Chemical Phenomena Associated with Geologic Disposal of High-Level Radioactive Waste

    NASA Astrophysics Data System (ADS)

    Park, Sang-Uk; Kim, Jun-Mo; Kihm, Jung-Hwi

    2014-05-01

    A series of numerical simulations was performed using a multiphase thermo-hydro-chemical numerical model to predict integratedly and evaluate quantitatively thermo-hydro-chemical phenomena due to heat generation associated with geologic disposal of high-level radioactive waste. The average mineralogical composition of the fifteen unweathered igneous rock bodies, which were classified as granite, in Republic of Korea was adopted as an initial (primary) mineralogical composition of the host rock of the repository of high-level radioactive waste in the numerical simulations. The numerical simulation results show that temperature rises and thus convective groundwater flow occurs near the repository due to heat generation associated with geologic disposal of high-level radioactive waste. Under these circumstances, a series of water-rock interactions take place. As a result, among the primary minerals, quartz, plagioclase (albite), biotite (annite), and muscovite are dissolved. However, orthoclase is initially precipitated and is then dissolved, whereas microcline is initially dissolved and is then precipitated. On the other hand, the secondary minerals such as kaolinite, Na-smectite, chlorite, and hematite are precipitated and are then partly dissolved. In addition, such dissolution and precipitation of the primary and secondary minerals change groundwater chemistry (quality) and induce reactive chemical transport. As a result, in groundwater, Na+, Fe2+, and HCO3- concentrations initially decrease, whereas K+, AlO2-, and aqueous SiO2 concentrations initially increase. On the other hand, H+ concentration initially increases and thus pH initially decreases due to dissociation of groundwater in order to provide OH-, which is essential in precipitation of Na-smectite and chlorite. Thus, the above-mentioned numerical simulation results suggest that thermo-hydro-chemical numerical simulation can provide a better understanding of heat transport, groundwater flow, and reactive

  1. Recent studies of nuclear and chemical properties of elements 103, 104 and 105

    SciTech Connect

    Hoffman, D.C. . Dept. of Chemistry Lawrence Berkeley Lab., CA )

    1990-08-01

    Information obtained since 1983 on the nuclear and chemical properties of element 103, the last on the actinide series, and elements 104 and 105, at the beginning of the transactinide series, is reviewed. Their chemical properties are compared with their lanthanide and lighter group 4 and 5 homologs and evidence for possible relativistic effects is discussed. The current knowledge of the nuclear properties of these elements and how these affect of the study of chemical properties is discussed. Some of the challenges involved in the study of short-lived isotopes which can only be produced an atom-at-a-time'' at an appropriate accelerator and the prognosis for future studies of these and still heavier elements are considered. 40 refs., 4 figs.

  2. On the occurrence of metallic character in the periodic table of the chemical elements.

    PubMed

    Hensel, Friedrich; Slocombe, Daniel R; Edwards, Peter P

    2015-03-13

    The classification of a chemical element as either 'metal' or 'non-metal' continues to form the basis of an instantly recognizable, universal representation of the periodic table (Mendeleeff D. 1905 The principles of chemistry, vol. II, p. 23; Poliakoff M. & Tang S. 2015 Phil. Trans. R. Soc. A 373: , 20140211). Here, we review major, pre-quantum-mechanical innovations (Goldhammer DA. 1913 Dispersion und Absorption des Lichtes; Herzfeld KF. 1927 Phys. Rev. 29: , 701-705) that allow an understanding of the metallic or non-metallic status of the chemical elements under both ambient and extreme conditions. A special emphasis will be placed on recent experimental advances that investigate how the electronic properties of chemical elements vary with temperature and density, and how this invariably relates to a changing status of the chemical elements. Thus, the prototypical non-metals, hydrogen and helium, becomes metallic at high densities; and the acknowledged metals, mercury, rubidium and caesium, transform into their non-metallic forms at low elemental densities. This reflects the fundamental fact that, at temperatures above the absolute zero of temperature, there is therefore no clear dividing line between metals and non-metals. Our conventional demarcation of chemical elements as metals or non-metals within the periodic table is of course governed by our experience of the nature of the elements under ambient conditions. Examination of these other situations helps us to examine the exact divisions of the chemical elements into metals and non-metals (Mendeleeff D. 1905 The principles of chemistry, vol. II, p. 23). PMID:25666074

  3. Total element concentration and chemical fractionation in airborne particulate matter from Santiago, Chile

    NASA Astrophysics Data System (ADS)

    Richter, Pablo; Griño, Paulina; Ahumada, Inés; Giordano, Ady

    Total element determination and chemical fractionation were carried out in airborne particulate matter (PM 10) from the Cerrillos monitoring station in Santiago, Chile, sampled in July (winter), 1997-2003. Element concentration in the period under study (1997-2003) was statistically analyzed through cluster analysis in order to identify groups of elements having similar behavior along time. Elements such as Cd, Cu, Pb, Ni, As and Mg show a clear decrease in concentration with time. On the contrary, chromium increases its concentration almost linearly during the period. In order to estimate whether the presence of a certain element in PM 10 matrix is mainly due to anthropogenic or natural processes, the enrichment factor of each element was determined. According to their behavior in the sequential extraction procedure, the elements were grouped by multivariate analysis in three clusters: (a) those mobile elements (Pb, Cd, Zn, Mn, Cu and As) which are weakly bound to the matrix (fractions 1 and 2) (b) those elements (V, Ti, and Cr) mainly bound to carbonates and oxides (fraction 3) and (c) the most immobile elements (Ni, Mo, Ca, Mg, Ba and Al), mainly bound to silicates and organic matter (fraction 4). A source of great concern is the fact that elements of such high toxicity as Pb, Cd and As are highly concentrated in both mobile fractions, indicating that these elements have a direct impact on the environment and on the health of the exposed population.

  4. Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt.

    PubMed

    Abbady, Adel G E; El-Arabi, A M; Abbady, A

    2006-01-01

    Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 microWm(-3) (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 microWm(-3) (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites. PMID:16120480

  5. Chemical element concentrations in four lichens on a transect entering Voyageurs National Park

    USGS Publications Warehouse

    Bennett, J.; Wetmore, C.M.

    1997-01-01

    A three factor transect study was conducted to test the hypothesis that chemical elements from air emissions in the vicinity of International Falls, Minnesota could not be detected in lichens along a 24 km transect reaching into Voyageurs National Park. It was hypothesized that element concentrations in lichens would decline exponentially downwind and would reach background values at a distance before the park boundary. Four species (Cladina rangiferina, Evernia mesomorpha, Hypogymnia physodes, and Parmelia sulcata) were sampled at ten sites for 3 years and 17 chemical elements were measured. The most notable result was a curvilinear geographic trend for many elements, which decreased from International Falls and then increased towards the park. This trend was significant for many anthropogenic elements, including S, Hg, Cd, and Cr, and for all four species. This type of distribution pattern has been observed in Hypogymnia physodes in other studies downwind of a steel mill and an oil refinery. Cladina, a ground-dwelling lichen, generally had lower tissue concentrations of the elements than the three epiphytic species. Tissue concentrations over the 3 years of sampling declined an average of 12%. Sufficient evidence exists to conclude that lichen tissue element concentrations in the vicinity of International Falls may be related to local air emissions, and that an exponential decline of element concentrations downwind of the sources does not apply to this situation.

  6. Relatively Long-Lived Dubnium Isotopes and Chemical Identification of Superheavy Elements

    SciTech Connect

    Tereshatov, E. E.; Voronyuk, M. G.; Starodub, G. Ya.; Petrushkin, O. V.; Dmitriev, S. N.; Bruchertseifer, H.

    2010-04-30

    The present study has been performed within the framework of experiments aimed at the investigation of chemical properties of long-lived Db isotopes in aqueous solutions. The isocratic anion exchange separations of group V elements in the solutions containing HF have been considered. Parameters of separation of dubnium homologues (Pa, Nb and Ta) in HF/HNO{sub 3} mixed solutions have been optimized. The procedure of separation of group V elements from multicomponent system has been suggested.

  7. Chemical studies of elements with Z ⩾ 104 in gas phase

    NASA Astrophysics Data System (ADS)

    Türler, Andreas; Eichler, Robert; Yakushev, Alexander

    2015-12-01

    Chemical investigations of superheavy elements in the gas-phase, i.e. elements with Z ≥ 104, allow assessing the influence of relativistic effects on their chemical properties. Furthermore, for some superheavy elements and their compounds quite unique gas-phase chemical properties were predicted. The experimental verification of these properties yields supporting evidence for a firm assignment of the atomic number. Prominent examples are the high volatility observed for HsO4 or the very weak interaction of Cn with gold surfaces. The unique properties of HsO4 were exploited to discover the doubly-magic even-even nucleus 270Hs and the new isotope 271Hs. The combination of kinematic pre-separation and gas-phase chemistry allowed gaining access to a new class of relatively fragile compounds, the carbonyl complexes of elements Sg through Mt. A not yet resolved issue concerns the interaction of Fl with gold surfaces. While competing experiments agree on the fact that Fl is a volatile element, there are discrepancies concerning its adsorption on gold surfaces with respect to its daughter Cn. The elucidation of these and other questions amounts to the fascination that gas-phase chemical investigations exert on current research at the extreme limits of chemistry today.

  8. Design and adaptation of a novel supercritical extraction facility for operation in a glove box for recovery of radioactive elements

    SciTech Connect

    Kumar, V. Suresh; Kumar, R.; Sivaraman, N.; Ravisankar, G.; Vasudeva Rao, P. R.

    2010-09-15

    The design and development of a novel supercritical extraction experimental facility adapted for safe operation in a glove box for the recovery of radioactive elements from waste is described. The apparatus incorporates a high pressure extraction vessel, reciprocating pumps for delivering supercritical fluid and reagent, a back pressure regulator, and a collection chamber. All these components of the system have been specially designed for glove box adaptation and made modular to facilitate their replacement. Confinement of these materials must be ensured in a glove box to protect the operator and prevent contamination to the work area. Since handling of radioactive materials under high pressure (30 MPa) and temperature (up to 333 K) is involved in this process, the apparatus needs elaborate safety features in the design of the equipment, as well as modification of a standard glove box to accommodate the system. As a special safety feature to contain accidental leakage of carbon dioxide from the extraction vessel, a safety vessel has been specially designed and placed inside the glove box. The extraction vessel was enclosed in the safety vessel. The safety vessel was also incorporated with pressure sensing and controlling device.

  9. Design and adaptation of a novel supercritical extraction facility for operation in a glove box for recovery of radioactive elements.

    PubMed

    Kumar, V Suresh; Kumar, R; Sivaraman, N; Ravisankar, G; Vasudeva Rao, P R

    2010-09-01

    The design and development of a novel supercritical extraction experimental facility adapted for safe operation in a glove box for the recovery of radioactive elements from waste is described. The apparatus incorporates a high pressure extraction vessel, reciprocating pumps for delivering supercritical fluid and reagent, a back pressure regulator, and a collection chamber. All these components of the system have been specially designed for glove box adaptation and made modular to facilitate their replacement. Confinement of these materials must be ensured in a glove box to protect the operator and prevent contamination to the work area. Since handling of radioactive materials under high pressure (30 MPa) and temperature (up to 333 K) is involved in this process, the apparatus needs elaborate safety features in the design of the equipment, as well as modification of a standard glove box to accommodate the system. As a special safety feature to contain accidental leakage of carbon dioxide from the extraction vessel, a safety vessel has been specially designed and placed inside the glove box. The extraction vessel was enclosed in the safety vessel. The safety vessel was also incorporated with pressure sensing and controlling device. PMID:20886994

  10. Chemical Evolution of R-process Elements in the Hierarchical Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Komiya, Yutaka; Shigeyama, Toshikazu

    2016-08-01

    The main astronomical source of r-process elements has not yet been identified. One plausible site is neutron star mergers (NSMs). From the perspective of Galactic chemical evolution, however, it has been pointed out that the NSM scenario is incompatible with observations. Recently, Tsujimoto & Shigeyama (2014) pointed out that NSM ejecta can spread into much larger volume than ejecta from a supernova. We re-examine the chemical evolution of r-process elements under the NSM scenario considering this difference in propagation of the ejecta. We find that the NSM scenario can be compatible with the observed abundances of the Milky Way halo stars.

  11. FINITE ELEMENT IMPLEMENTATION OF MECHANO-CHEMICAL PHENOMENA IN NEUTRAL DEFORMABLE POROUS MEDIA UNDER FINITE DEFORMATION

    PubMed Central

    ATESHIAN, GERARD A.; ALBRO, MICHAEL B.; MAAS, STEVE; WEISS, JEFFREY A.

    2012-01-01

    Biological soft tissues and cells may be subjected to mechanical as well as chemical (osmotic) loading under their natural physiological environment or various experimental conditions. The interaction of mechanical and chemical effects may be very significant under some of these conditions, yet the highly nonlinear nature of the set of governing equations describing these mechanisms poses a challenge for the modeling of such phenomena. This study formulated and implemented a finite element algorithm for analyzing mechano-chemical events in neutral deformable porous media under finite deformation. The algorithm employed the framework of mixture theory to model the porous permeable solid matrix and interstitial fluid, where the fluid consists of a mixture of solvent and solute. A special emphasis was placed on solute-solid matrix interactions, such as solute exclusion from a fraction of the matrix pore space (solubility) and frictional momentum exchange that produces solute hindrance and pumping under certain dynamic loading conditions. The finite element formulation implemented full coupling of mechanical and chemical effects, providing a framework where material properties and response functions may depend on solid matrix strain as well as solute concentration. The implementation was validated using selected canonical problems for which analytical or alternative numerical solutions exist. This finite element code includes a number of unique features that enhance the modeling of mechano-chemical phenomena in biological tissues. The code is available in the public domain, open source finite element program FEBio (http://mrl.sci.utah.edu/software). PMID:21950898

  12. Extraction processes and solvents for recovery of cesium, strontium, rare earth elements, technetium and actinides from liquid radioactive waste

    DOEpatents

    Zaitsev, Boris N.; Esimantovskiy, Vyacheslav M.; Lazarev, Leonard N.; Dzekun, Evgeniy G.; Romanovskiy, Valeriy N.; Todd, Terry A.; Brewer, Ken N.; Herbst, Ronald S.; Law, Jack D.

    2001-01-01

    Cesium and strontium are extracted from aqueous acidic radioactive waste containing rare earth elements, technetium and actinides, by contacting the waste with a composition of a complex organoboron compound and polyethylene glycol in an organofluorine diluent mixture. In a preferred embodiment the complex organoboron compound is chlorinated cobalt dicarbollide, the polyethylene glycol has the formula RC.sub.6 H.sub.4 (OCH.sub.2 CH.sub.2).sub.n OH, and the organofluorine diluent is a mixture of bis-tetrafluoropropyl ether of diethylene glycol with at least one of bis-tetrafluoropropyl ether of ethylene glycol and bis-tetrafluoropropyl formal. The rare earths, technetium and the actinides (especially uranium, plutonium and americium), are extracted from the aqueous phase using a phosphine oxide in a hydrocarbon diluent, and reextracted from the resulting organic phase into an aqueous phase by using a suitable strip reagent.

  13. Melting points and chemical bonding properties of 3d transition metal elements

    NASA Astrophysics Data System (ADS)

    Takahara, Wataru

    2014-08-01

    The melting points of 3d transition metal elements show an unusual local minimal peak at manganese across Period 4 in the periodic table. The chemical bonding properties of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper are investigated by the DV-Xα cluster method. The melting points are found to correlate with the bond overlap populations. The chemical bonding nature therefore appears to be the primary factor governing the melting points.

  14. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    SciTech Connect

    Delegard, C.H.; Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K.

    1995-05-01

    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes.

  15. Some radioactive-elements in the coastal sediments of the Mediterranean Sea.

    PubMed

    Radi Dar, Mahmoud A; El-Saharty, Abeer A

    2013-03-01

    The radioactivities of (234+235)U, (232)Th, (40)K and (137)Cs were measured in the coastal sediments of the western Mediterranean Sea between Alexandria and Salloum, Egypt. The recorded activities of the natural radionuclides were within the range of those measured worldwide. The highest activities of (234+235)U and (40)K (166.5 ± 7.7; 365.8 ± 2.3 Bq kg(-1) dry weight) were measured at Sidi Krir station while El-Max station recorded the highest (232)Th activity (22.7 ± 0.6 Bq kg(-1) dry weight) indicating that these radionuclides may accumulate in ionic and particulate forms from the drainage systems of the fertiliser, petrochemical and paper industries and from agricultural drains and also as the drifted particulates from longshore currents and accretion processes. The lowest (234+235)U activities were recorded at Salloum and the lowest (232)Th and (40)K activities were recorded at El-Hammam, indicating that the accretion process is more active in the eastern Mediterranean. Salloum recorded the highest activity levels for (137)Cs (7.9 ± 0.4 Bq kg(-1) dry weight) showing significant increases of the artificial (137)Cs westwards that may be indicative of to the anthropogenic sources from the northern Mediterranean. PMID:22719046

  16. Simulating the Changes of Minerals and Elements under Chemical Weathering by Acid Hydrothermal Experiments

    NASA Astrophysics Data System (ADS)

    Lo, F.; Chen, H.

    2013-12-01

    In paleoenvironmental research, previous investigations reveal that the intensity of chemical weathering can be inferred from the elemental variations of marine or lacustrine sediments. Different kinds of rocks from Taiwan were applied in hydrothermal experiments to simulate element proportions and leaching sequence under chemical weathering. In our experiments, powder samples (2g) are treated in sulfuric acid solutions (20 ml) of 0.05M and 0.5M at 150°C for 1, 4, 7, 14, 30 and 60 days, respectively. We can further discuss mineral alteration and relative elemental migration according to the experimental results. There is no obvious variation in mineral phase and element at 0.05M, but the results of 0.5M have significant variations. The elemental contents are affected by the mineral leaching and secondary mineral deposited, so we use XRD and SEM to identify the existence of secondary minerals and their compositions. Our research exhibits that K/Rb, Ti/Al and Rb/Sr ratios show similar trend in most parent rocks (i.e. granite, andesite, quartz sandstone, calcite sandstone and mudstone) at 0.5M long-term experiments; however, the CIA value, was generally used as the proxy of chemical weathering, keep in a stable condition. The K/Rb and Ti/Al ratio increase, but Rb/Sr ratio decreases. In contrast, the actinolite schist and serpentinite show the different result. It is probably caused by the major mineral, chlorite and serpentinite in the rocks. We conclude that the major element Ti is relatively stable. Therefore, we use each element divided by Ti for judging relatively enriched or depleted under chemical weathering processes. Finally, we find that K/Rb ratio, which has obvious variations, is seldom influenced by mineral assemblage, so it can be regarded as a suitable weathering proxy.

  17. Chemical and mineralogical modifications of simplified radioactive waste calcine during heat treatment

    NASA Astrophysics Data System (ADS)

    Monteiro, A.; Schuller, S.; Toplis, M. J.; Podor, R.; Ravaux, J.; Clavier, N.; Brau, H. P.; Charpentier, T.; Angeli, F.; Leterrier, N.

    2014-05-01

    The microstructural and mineralogical changes associated with heating calcined mixtures of Al(NO3)3ṡ9H2O-NaNO3 have been studied. This system is a simplified analogue of high-level radioactive waste calcine, one of the raw materials used in the vitrification process employed for waste management. The decomposition (dehydration and denitration) and formation of secondary crystalline phases have been studied by differential thermal and gravimetric analysis (DTA & TGA), and heat-treated products characterized by X-ray diffraction, Raman spectroscopy, Nuclear Magnetic Resonance (NMR) and Transmission Electron Microscopy (TEM). It is found that pure Al(NO3)3ṡ9H2O transforms to amorphous Al2O3 at a temperature of ∼180 °C, well below that of the calcination process (500 °C). This amorphous Al2O3 is highly porous with a high specific surface area, but may in turn convert to denser γ-Al2O3 and α-Al2O3 with increasing temperature. On the other hand, pure NaNO3 remains stable up to ∼880 °C, despite a solid-liquid transition at ∼320 °C. For Al(NO3)3ṡ9H2O-NaNO3 mixtures, the products of calcination at 500 °C are found to consist of very fine porous material containing Na, Al and O, in addition to a variable proportion of well-defined crystals consisting of Na, and O. Heating these mixtures to temperatures of up to 1000 °C shows that for the case 80% Al(NO3)3ṡ9H2O -20% NaNO3 (weight%) a variety of crystalline sodium aluminates is formed (NaAlO2, NaAl11O17, NaAl6O9.5), while for the 50-50 mixture, only NaAlO2 is found. In large amounts, addition of alumina thus leads to the formation of crystalline phases rich in Al2O3 that are responsible for hardening the calcine as the temperature rises. The kinetics of nitrogen loss from NaNO3 are also found to be influenced by the relative proportion of Al(NO3)3ṡ9H2O in the calcine, larger amounts of Al leading to denitration at lower temperature. These results constitute the necessary background for understanding

  18. Chemical Identification of a Long-Lived Isotope of Dubnium, a Descendant of Element 115

    SciTech Connect

    Stoyer, N J; Landrum, J H; Wilk, P A; Moody, K J; Kenneally, J M; Shaughnessy, D A; Stoyer, M A; Wild, J F; Lougheed, R W; Dmitriev, S N; Oganessian, Y T; Shishkin, S V; Aksenov, N V; Tereshatov, E E; Bozhikov, G A; Vostokin, G K; Utyonkov, V K; Yeremin, A A

    2006-09-26

    The recognition criterion for discovery of a new chemical element includes two aspects, the characterization properties and the assignment properties. In this paper, we will discuss the status of element 115 experiments that have been performed in Dubna, Russia, highlighting the characterization and assignment properties as they specifically relate to a recent experiment. After discussing the status of what is known about the decay properties of element 115 [1], observed previously using the Dubna Gas-Filled Recoil Separator, we will discuss the prior chemical studies that have been performed on the Db descendant of element 115 [2]. Following the success of that experiment, some additional chemical information was desired. Two separation chemistries were then developed at LLNL and JINR. LLNL utilized reversed phase chromatography and JINR utilized anion exchange chromatography to perform not only +4/+5 separations, but also intra-group separations, where Nb-like and Ta-like fractions were eluted. The results from an experiment using these chemistries for the first time during December 2005 in Dubna, Russia, will be compared with prior chemical results. We will conclude with a discussion of possible enhancements to the work already performed and the current status of the future experimental plans.

  19. Chemical elements diffusion in the stainless steel components brazed with Cu-Ag alloy

    NASA Astrophysics Data System (ADS)

    Voiculescu, I.; Geanta, V.; Vasile, I. M.; Binchiciu, E. F.; Winestoock, R.

    2016-06-01

    The paper presents the study of diffusion of chemical elements through a brazing joint, between two thin components (0.5mm) made of stainless steel 304. An experimental brazing filler material has been used for brazing stainless steel component and then the diffusion phenomenon has been studied, in terms of chemical element displacement from the brazed separation interface. The filler material is in the form of a metal rod coated with ceramic slurry mixture of minerals, containing precursors and metallic powders, which can contribute to the formation of deposit brazed. In determining the distance of diffusion of chemical elements, on both sides of the fusion line, were performed measurements of the chemical composition using electron microscopy SEM and EDX spectrometry. Metallographic analysis of cross sections was performed with the aim of highlight the microstructural characteristics of brazed joints, for estimate the wetting capacity, adherence of filler metal and highlight any imperfections. Analyzes performed showed the penetration of alloying elements from the solder (Ag, Cu, Zn and Sn) towards the base material (stainless steel), over distances up to 60 microns.

  20. Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

    DOEpatents

    Rose, Volker; Preissner, Curt A; Hla, Saw-Wai; Wang, Kangkang; Rosenmann, Daniel

    2014-09-30

    A method and system for performing simultaneous topographic and elemental chemical and magnetic contrast analysis in a scanning, tunneling microscope. The method and system also includes nanofabricated coaxial multilayer tips with a nanoscale conducting apex and a programmable in-situ nanomanipulator to fabricate these tips and also to rotate tips controllably.

  1. A Game-Based Approach to Learning the Idea of Chemical Elements and Their Periodic Classification

    ERIC Educational Resources Information Center

    Franco-Mariscal, Antonio Joaquín; Oliva-Martínez, José María; Blanco-López, Ángel; España-Ramos, Enrique

    2016-01-01

    In this paper, the characteristics and results of a teaching unit based on the use of educational games to learn the idea of chemical elements and their periodic classification in secondary education are analyzed. The method is aimed at Spanish students aged 15-16 and consists of 24 1-h sessions. The results obtained on implementing the teaching…

  2. Canister arrangement for storing radioactive waste

    DOEpatents

    Lorenzo, Donald K.; Van Cleve, Jr., John E.

    1982-01-01

    The subject invention relates to a canister arrangement for jointly storing high level radioactive chemical waste and metallic waste resulting from the reprocessing of nuclear reactor fuel elements. A cylindrical steel canister is provided with an elongated centrally disposed billet of the metallic waste and the chemical waste in vitreous form is disposed in the annulus surrounding the billet.

  3. Canister arrangement for storing radioactive waste

    DOEpatents

    Lorenzo, D.K.; Van Cleve, J.E. Jr.

    1980-04-23

    The subject invention relates to a canister arrangement for jointly storing high level radioactive chemical waste and metallic waste resulting from the reprocessing of nuclear reactor fuel elements. A cylindrical steel canister is provided with an elongated centrally disposed billet of the metallic waste and the chemical waste in vitreous form is disposed in the annulus surrounding the billet.

  4. Applications of the Method of Space-Time Conservation Element and the Solution Element to Unsteady Chemically Reactive Flows

    NASA Technical Reports Server (NTRS)

    Yu, Sheng-Tao

    2001-01-01

    This document reports the conclusion and findings of our research activities for this grant. The goal of the project is the development and application of the method of Space-Time Conservation Element and Solution Element, or the CE/SE method, to simulate chemically reacting flows. The product of this project will be a high-fidelity, time-accurate flow solver analyzing unsteady flow fields advanced propulsion concepts, including the low-emission turbojet engine combustion and flow fields of the Pulse Detonation Engines (PDE). Based on the documents and computer software of the CE/SE method that we have received from the CE/SE working group at NASA Lewis, we have focused our research effort on addressing outstanding technical issues related to the extension of the CE/SE method for unsteady, chemically reactive flows. In particular, we have made progresses in the following three aspects: (1) Derivation of the governing equations for reacting flows; (2) Numerical treatments of stiff source terms; and (3) Detailed simulations of ZND detonation waves.

  5. Initial chemical transport of reducing elements and chemical reactions in oxide cathode base metal1

    NASA Astrophysics Data System (ADS)

    Roquais, J. M.; Poret, F.; le Doze, R.; Dufour, P.; Steinbrunn, A.

    2002-11-01

    In the present work, the formation of compounds associated to the diffusion of reducing elements (Mg and Al) to the nickel surface of a one-piece oxide cathode has been studied. Those compounds have been evidenced after the annealing steps at high temperature performed on cathode base metal prior to the emitting coating deposition. Therefore, they form the "initial" interface between the nickel and the coating, in other words, the interface existing at the beginning of cathode life. Extensive analysis to characterize the nickel base prior to coating deposition has been performed by means of scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and glow discharge optical emission spectroscopy (GDOES). TEM and AES analysis have allowed to identify for the first time a spinel compound of MgAl 2O 4. The preferential distribution of the different compounds on the nickel surface has been studied by EDX mapping. Experimental profiles of diffusion of the reducing elements in the nickel have been obtained over the entire thickness of the material by GDOES. The mechanism of formation of these compounds together with a related diffusion model are proposed.

  6. Radiochemical Separation of Group 5 Elements. Model Experiments for Investigation of Dubnium Chemical Behaviour

    SciTech Connect

    Tereshatov, E. E.; Bozhikov, G. A.; Aksenov, N. V.; Starodub, G. Ya.; Vostokin, G. K.; Shishkin, S. V.; Dmitriev, S. N.; Bruchertseifer, H.; Gaeggeler, H. W.

    2007-05-22

    Chemical behaviour of group 5 elements in the aqueous hydrofluoric acid solutions was studied. The radiochemical method for the cation exchange separation of Nb (Pa) and Ta from Zr, Hf and lanthanides is presented. The developed scheme allows excluding of the presence of SF heavy actinides in fractions of separated elements. On the basis of the data of the present work, it is possible to suggest the following order of the stability of the fluoride complexes of group 4 and 5 elements: Nb {approx_equal} Pa > Zr > Hf > Ta. The order of the complex formation is in agreement with theoretical predictions. This analytical procedure can be used in future heavy nuclei synthesis experiments for the separation of dubnium (Db) from other reactions products and for its chemical identification.

  7. The chemical behavior of transuranium elements and barrier functions in natural aquifer systems

    SciTech Connect

    Kim, Jae-Il

    1993-12-31

    The chemical behavior of transuranium elements in natural aquifer systems is governed by a variety of geochemical reactions, such as dissolution reaction (solubility), hydrolysis, complexation with inorganics or organics, redox reaction, colloid formation, geochemical interaction with surfaces of various minerals, coprecipitation, mineralization, etc. This paper reviews the present state of knowledge on some of these particular reactions. The emphasis here is on how the individual reactions can be appraised for long-term prediction of the geochemical behavior of transuranium elements in the natural environment. Of the various possible reactions, the primary thermodynamic processes are discussed with notable examples: dissolution of transuranium compounds in aquatic solution; complexation with important anions present in groundwater; and colloid generation. Various laser spectroscopic methods in use for chemical speciation are mentioned briefly for their spectroscopic capability, as well as for their applicability. The present paper attempts to better understand the migration behavior of transuranium elements in natural aquifer systems.

  8. Calculations of the moon's thermal history at different concentrations of radioactive elements, taking into account differentiation on melting

    NASA Technical Reports Server (NTRS)

    Ornatskaya, O. I.; Alber, Y. I.; Ryazantseva, I. L.

    1977-01-01

    Calculations of the thermal history of the moon were done by solving the thermal conductivity equation for the case in which the heat sources are the long lived radioactive elements Th, U, and K-40. The concentrations of these elements were adjusted to give 4 variations of heat flow. Calculations indicated that the moon's interior was heated to melting during the first 0.7 to 2.3 x 10 to the 9th power years. The maximum fusion involved practically the entire moon to a distance from 15 to 45 km beneath the surface, and started 3.5 to 4.0 x 10 to the 9th power years ago, or 2.5 x 3.0 x 10 to the 9th power years ago and continued for 1 to 2 x 10 to the 9th power years. The moon today is cooling. The current thickness of the solid crust is from 150 to 200 km and the heat flow exceeds the stationary value 1.5 fold.

  9. Chemical aspects of pellet-cladding interaction in light water reactor fuel elements

    SciTech Connect

    Olander, D.R.

    1982-01-01

    In contrast to the extensive literature on the mechanical aspects of pellet-cladding interaction (PCI) in light water reactor fuel elements, the chemical features of this phenomenon are so poorly understood that there is still disagreement concerning the chemical agent responsible. Since the earliest work by Rosenbaum, Davies and Pon, laboratory and in-reactor experiments designed to elucidate the mechanism of PCI fuel rod failures have concentrated almost exclusively on iodine. The assumption that this is the reponsible chemical agent is contained in models of PCI which have been constructed for incorporation into fuel performance codes. The evidence implicating iodine is circumstantial, being based primarily upon the volatility and significant fission yield of this element and on the microstructural similarity of the failed Zircaloy specimens exposed to iodine in laboratory stress corrosion cracking (SCC) tests to cladding failures by PCI.

  10. Chemical Differentiation of Osseous, Dental, and Non-skeletal Materials in Forensic Anthropology using Elemental Analysis.

    PubMed

    Zimmerman, Heather A; Meizel-Lambert, Cayli J; Schultz, John J; Sigman, Michael E

    2015-03-01

    Forensic anthropologists are generally able to identify skeletal materials (bone and tooth) using gross anatomical features; however, highly fragmented or taphonomically altered materials may be problematic to identify. Several chemical analysis techniques have been shown to be reliable laboratory methods that can be used to determine if questionable fragments are osseous, dental, or non-skeletal in nature. The purpose of this review is to provide a detailed background of chemical analysis techniques focusing on elemental compositions that have been assessed for use in differentiating osseous, dental, and non-skeletal materials. More recently, chemical analysis studies have also focused on using the elemental composition of osseous/dental materials to evaluate species and provide individual discrimination, but have generally been successful only in small, closed groups, limiting their use forensically. Despite significant advances incorporating a variety of instruments, including handheld devices, further research is necessary to address issues in standardization, error rates, and sample size/diversity. PMID:25753999

  11. VizieR Online Data Catalog: ASPCAP weights for the 15 APOGEE chemical elements (Garcia+, 2016)

    NASA Astrophysics Data System (ADS)

    Garcia Perez, A. E.; Allende Prieto, C.; Holtzman, J. A.; Shetrone, M.; Meszaros, S.; Bizyaev, D.; Carrera, R.; Cunha, K.; Garcia-Hernandez, D. A.; Johnson, J. A.; Majewski, S. R.; Nidever, D. L.; Schiavon, R. P.; Shane, N.; Smith, V. V.; Sobeck, J.; Troup, N.; Zamora, O.; Weinberg, D. H.; Bovy, J.; Eisenstein, D. J.; Feuillet, D.; Frinchaboy, P. M.; Hayden, M. R.; Hearty, F. R.; Nguyen, D. C.; O'Connell, R. W.; Pinsonneault, M. H.; Wilson, J. C.; Zasowski, G.

    2016-07-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R~22500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. The pipeline matches the observations to a set of synthetic spectrum templates using the {chi}2 minimization in a multidimensional parameter space. Stellar parameters are derived first from the entire APOGEE spectral range, followed by the determination of individual chemical abundances from spectral windows optimized for each element. Table3 gives the weights as a function of wavelength, for the 15 APOGEE chemical elements. (1 data file).

  12. Structure of matter, radioactivity, and nuclear fission. Volume 3

    SciTech Connect

    Not Available

    1986-01-01

    Subject matter includes structure of matter (what is matter, forces holding atoms together, visualizing the atom, the chemical elements, atomic symbols, isotopes, radiation from the atom), radioactivity (what holds the nucleus together, can one element change into another element, radiation from the nucleus, half-life, chart of the nuclides), and nuclear fission (nuclear energy release, the fission process, where does fission energy go, radiation and radioactivity resulting from fission).

  13. Abnormal chemical element concentrations in lichens of Isle Royale National Park

    USGS Publications Warehouse

    Bennett, J.P.

    1995-01-01

    Lichens have been used for many years to monitor changes in deposited airborne chemical elements in many areas, but few studies have focused on areas suspected of experiencing slightly elevated pollution. Detection of subtle patterns of slightly elevated pollutants calls for developing several lines of evidence as opposed to single line studies used in heavily polluted areas. This study of two lichen species, Hypogymnia physodes and Evernia mesomorpha, in Isle Royale National Park, Michigan compares the concentrations and ranks of elements with the concentrations and ranks of the elements in the earth's crust, changes in element concentrations over a nine year period, and the geography of element concentrations in the park. S, Zn, Pb, Cd and Se were elevated in both species and higher in rank compared to the concentrations and ranks in the earth's crust. Toxic elements increased 123% in Hypogymnia and 62% in Evernia over 9 years, compared to increases of 45% and 59% for non-toxic elements in each species, respectively. Geographically, the lichens at certain localities with higher exposures experienced higher than average element concentrations. Finally, tissue concentrations of Mn, S and Se at some localities were above levels known to be either toxic or similar to those found in polluted areas. These four lines of evidence suggest that Isle Royale National Park is experiencing the onset of chronic air pollution stress from a number of sources.

  14. The uses of synchrotron radiation sources for elemental and chemical microanalysis

    SciTech Connect

    Chen, J.R.; Chao, E.C.T.; Minkin, J.A.; Back, J.M.; Jones, K.W.; Rivers, M.L.; Sutton, S.R.; Geological Survey, Reston, VA; Brookhaven National Lab., Upton, NY )

    1989-08-01

    Synchrotron radiation sources offer important features for the analysis of a material. Among these features is the ability to determine both the elemental composition of the material and the chemical state of its elements. For microscopic analysis synchrotron x-ray fluorescence (SXRF) microprobes now offer spatial resolutions of 10{mu}m with minimum detection limits in the 1--10 ppM range depending on the nature of the sample and the synchrotron source used. This paper describes the properties of synchrotron radiation and their importance for elemental analysis, existing synchrotron facilities and those under construction that are optimum for SXRF microanalysis, and a number of applications including the high energy excitation of the K lines of heavy elements, microtomography, and XANES and EXAFS spectroscopies. 45 refs., 8 figs., 1 tab.

  15. The uses of synchrotron radiation sources for elemental and chemical microanalysis

    USGS Publications Warehouse

    Chen, J.R.; Chao, E.C.T.; Minkin, J.A.; Back, J.M.; Jones, K.W.; Rivers, M.L.; Sutton, S.R.

    1990-01-01

    Synchrotron radiation sources offer important features for the analysis of a material. Among these features is the ability to determine both the elemental composition of the material and the chemical state of its elements. For microscopic analysis synchrotron X-ray fluorescence (SXRF) microprobes now offer spatial resolutions of 10 ??m with minimum detection limits in the 1-10 ppm range depending on the nature of the sample and the synchrotron source used. This paper describes the properties of synchrotron radiation and their importance for elemental analysis, existing synchrotron facilities and those under construction that are optimum for SXRF microanalysis, and a number of applications including the high energy excitation of the K lines of heavy elements, microtomography, and XANES and EXAFS spectroscopies. ?? 1990.

  16. Experiments on rehabilitation of radioactive metallic waste (RMW) of reactor stainless steels of Siberian chemical plant

    NASA Astrophysics Data System (ADS)

    Kolpakov, G. N.; Zakusilov, V. V.; Demyanenko, N. V.; Mishin, A. S.

    2016-06-01

    Stainless steel pipes, used to cool a reactor plant, have a high cost, and after taking a reactor out of service they must be buried together with other radioactive waste. Therefore, the relevant problem is the rinse of pipes from contamination, followed by returning to operation.

  17. Number of minerals of various chemical elements: Statistics 2012 (a new approach to an old problem)

    NASA Astrophysics Data System (ADS)

    Krivovichev, V. G.; Charykova, M. V.

    2014-12-01

    A list of all mineral species (4809) approved by IMA to 2012 inclusive has been compiled. The crystal chemical formulae of these minerals has been reviewed; each mineral species is marked by a set of the n-component chemical system (where n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10). The leading chemical elements by number of mineral species in the Earth's crust are as follows (number of mineral species is in parentheses): oxygen (3929), hydrogen (2700), silicon (1420), calcium (1130), sulfur (978), aluminum (959), iron (920), sodium (850), copper (588), phosphorus (559), magnesium (547), and arsenic (536). The taxonomy of mineral species is discussed. The important advantage of the proposed systematics is the possibility to range mineral species in strict order, in which each of them would have a unique position. A simple way of ordering minerals opens up possibilities for computer indexing of thermodynamic information. Within each system, minerals are arranged in order of the number of atoms of the first element and, within the group of compounds with the same number of atoms of the first element, in order of the number of atoms of the second element, and so on.

  18. Chemical speciation and leaching properties of elements in municipal incinerator ashes

    SciTech Connect

    Kida, Akiko; Noma, Yukio; Imada, Teruji

    1996-12-31

    Different chemical properties of bottom ash and fly ash from municipal solid waste incinerators were compared based on the results of the five measuring techniques: (1) total contents and leaching amounts by regulatory leaching test in Japan; (2) leaching properties by pH-dependent leaching test; (3) modeling of pH-dependent leaching test using model compounds; (4) enriched chemical composition compared with bulk composition by an X-ray photoelectron spectrometer (XPS); (5) estimation of chemical states of elements by XPS analysis. The difference between bottom ash and EP ash was clearly found in element content, leaching behavior and release rate. The release rates of many elements in bottom ash were lower than in electrostatic precipitation (EP) ash even in an acidic condition of pH 3 as well as at the inherent pH of 12. Corresponding to the relatively complicated components in bottom ash, leaching patterns depending on pH were not simple. Comparison between the pH-dependent pattern of Ca in a sample and in model compounds resulted in the estimation of some Ca compounds in ash. The surface analysis by XPS showed results that Na, Cl, Zn, Pb and S were enriched in EP ash and Fe and Ti were rarely found in the surface of ash. Possible chemical states of Na, Ca, K, Cl and S were estimated by a new method of comparing binding energies of standard compounds and their mixtures.

  19. An optical region elemental abundance analysis of the chemically peculiar HgMn star chi Lupi

    NASA Technical Reports Server (NTRS)

    Wahlgren, Glenn M.; Adelman, Saul J.; Robinson, Richard D.

    1994-01-01

    The optical spectrum of the chemically peculiar HgMn type binary star chi Lupi has been analyzed to determine atmospheric parameters and elemental abundances. Echelle spectra were obtained with the 3.9 m Anglo-Australian telescope to exploit the extreme shape-lined nature of the spectrum. This study was undertaken in support of ultraviolet analyses currently underway that utilize echell spectra obtained with the Hubble Space Telescope. For the B9.5 V primary star we obtain T(sub eff) = 10650 K, log g = 3.9, and xi = 0 km/s, while for the A2 V secondary, T(sub eff) = 9200 K, log g = 4.0, and xi = 2 km/s. Most of the elemental abundances are typical of HgMn stars with similar T(sub eff) showing an overall iron-peak elemental abundance distribution that is basically solar in nature with enhancement of the light elements Si, P, and S, as well as all detected elements heavier than the iron group. Abundances for several elements have been determined for the first time in this star, including several of the rare-earths. The secondary star spectrum shows Am star characteristics. We also discuss the relative merits of the equivalent width and synthetic spectrum techniques in determining the elemental abundences, concluding that the synthetic spectrum technique is necessary for obtaining abundances with the utmost accuracy.

  20. Chemical element concentrations in liquids and solids associated with power plants using FGD systems

    SciTech Connect

    Wangen, L.E.; Jones, M.M.

    1981-08-01

    Solid and liquid process steam samples from eight power plants using wet flue gas desulfurization (FGD) scrubbers have been analyzed for the trace elements As, B, Br, Cl, Cd, Co, Cr, F, Ga, I, Mo, Ni, Pb, S, Sb, Se, Th, U, V, W, and Zn as well as several major and minor elements. Four plants burned high-sulfur coals and three burned low-sulfur coals. One plant used a low-sulfur lignite coal. Four FGD systems used limestone, two used lime, and two used alkaline flyash as scrubbing reagent. Elemental concentration data were used to identify chemical elements of concern regarding their potential for causing environmental harm as a result of the disposal of residues associated with FGD systems. Elemental concentrations were evaluated by the Environmental Protection Agency's minimum acute-toxicity-of-effluents criteria. Calcium, Mg, Mn, Ni, Se, and SO/sub 4//sup 2 -/ were identified as most generally problematic. The elements B, Cd, F, and Mo were judged as potentially problematic in certain situations. Generally FGD liquors from power plants that burned low-sulfur western coals had highest concentrations of most trace elements.

  1. Chemical properties of the transactinide elements studied inliquid phase with SISAK

    SciTech Connect

    Omtvedt, J.P.; Alstad, J.; Bjornstad, T.; Dullmann, Ch.E.; Gregorich, K.E.; Hoffman, D.C.; Nitsche, H.; Opel, K.; Polakova, D.; Samadani, F.; Schulz, F.; Skarnemark, G.; Stavsetra, L.; Sudowe, R.; Zheng, L.

    2007-05-01

    This article starts with a review of the current SISAKliquid-liquid extraction system, as used after the physical preseparatorBGS at LBNL for chemical studies of transactinide elements. Emphasis willbe on new additions and developments. Then the possibilities offered bythe new TASCA separator at GSI and the use of actinide targets at bothGSI and LBNL are discussed with respect to future SISAK transactinideexperiments. Finally, current and future liquid-liquid extraction systemsfor studying elements Rf up to Hs are discussed.

  2. Extraction of information from major element chemical analyses of lunar basalts

    NASA Technical Reports Server (NTRS)

    Butler, J. C.

    1985-01-01

    Major element chemical analyses often form the framework within which similarities and differences of analyzed specimens are noted and used to propose or devise models. When percentages are formed the ratios of pairs of components are preserved whereas many familiar statistical and geometrical descriptors are likely to exhibit major changes. This ratio preserving aspect forms the basis for a proposed framework. An analysis of compositional variability within the data set of 42 major element analyses of lunar reference samples was selected to investigate this proposal.

  3. Chemical cleaning of porous stainless steel cross-flow filter elements for nuclear waste applications

    SciTech Connect

    Billing, Justin M.; Daniel, Richard C.; Hallen, Richard T.; Schonewill, Philip P.; Shimskey, Rick W.; Peterson, Reid A.

    2011-05-10

    The Waste Treatment and Immobilization Plant (WTP) currently under construction for treatment of High-Level Waste (HLW) at the Hanford Site will rely on cross-flow ultrafiltration to provide solids-liquid separation as a core part of the treatment process. To optimize process throughput, periodic chemical cleaning of the porous stainless steel filter elements has been incorporated into the design of the plant. It is currently specified that chemical cleaning with nitric acid will occur after significant irreversible membrane fouling is observed. Irreversible fouling is defined as fouling that cannot be removed by backpulsing the filter. PNNL has investigated chemical cleaning processes as part of integrated tests with HLW simulants and with actual Hanford tank wastes. To quantify the effectiveness of chemical cleaning, the residual membrane resistance after cleaning was compared against the initial membrane resistance for each test in a series of long-term fouling tests. The impact of the small amount of residual resistance in these tests could not be separated from other parameters and the historical benchmark of >1 GPM/ft2 for clean water flux was determined to be an adequate metric for chemical cleaning. Using the results from these tests, a process optimization strategy is presented suggesting that for the simulant material under test, the value of chemical cleaning may be suspect. The period of enhanced filtration may not be enough to offset the down time required for chemical cleaning, without respect to the other associated costs.

  4. REDOX state analysis of platinoid elements in simulated high-level radioactive waste glass by synchrotron radiation based EXAFS

    NASA Astrophysics Data System (ADS)

    Okamoto, Yoshihiro; Shiwaku, Hideaki; Nakada, Masami; Komamine, Satoshi; Ochi, Eiji; Akabori, Mitsuo

    2016-04-01

    Extended X-ray Absorption Fine Structure (EXAFS) analyses were performed to evaluate REDOX (REDuction and OXidation) state of platinoid elements in simulated high-level nuclear waste glass samples prepared under different conditions of temperature and atmosphere. At first, EXAFS functions were compared with those of standard materials such as RuO2. Then structural parameters were obtained from a curve fitting analysis. In addition, a fitting analysis used a linear combination of the two standard EXAFS functions of a given elements metal and oxide was applied to determine ratio of metal/oxide in the simulated glass. The redox state of Ru was successfully evaluated from the linear combination fitting results of EXAFS functions. The ratio of metal increased at more reducing atmosphere and at higher temperatures. Chemical form of rhodium oxide in the simulated glass samples was RhO2 unlike expected Rh2O3. It can be estimated rhodium behaves according with ruthenium when the chemical form is oxide.

  5. Analysis of chemical samples for environmental levels of radioactivity using a massively shielded 18% Ge(Li) system

    NASA Astrophysics Data System (ADS)

    Blanchard, Fred A.; Lickly, Tim D.

    1984-01-01

    An environmental level gamma radioactivity analysis system has been assembled from a commercially available, high sensitivity, high resolution, low background Ge(Li) detector with associated electronics (without coincidence or anticoincidence) and massive shielding with old iron. A variety of chemicals have been examined as part of a background baseline survey using quantitative peak or gross gamma analysis of the Ge(Li) gamma ray spectrum from a two liter sample in a Marinelli beaker. Gamma peak analysis had a calculated sensitivity (for a 30 min count) of 0.01 to 0.21 pCi/g, depending on sample bulk density, for an isotope such as 137Cs. A similar sensitivity (0.1 pCi/g) was obtained by gross gamma analysis for any mixture of isotopes. A method for estimating the necessary integral background value for samples of different bulk densities was developed. The methods are capable of demonstrating existing natural radioactivity as shown by the 40K and uranium, thorium and their daughters observed in about 16% of the chemicals tested. Especially noticeable were 40K, 228Ac, 212Pb, 208Tl, 214Pb, and 214Bi. The levels and isotopes were similar to those found in soils and common salts.

  6. Stratospheric Sampling and In Situ Atmospheric Chemical Element Analysis During Meteor Showers: A Resource Study

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    2000-01-01

    Resources studies for asteroidal mining evaluation have depended historically on remote sensing analysis for chemical elements. During the November 1998 Leonids meteor shower, a stratospheric balloon and various low-density capture media were used to sample fragments from Comet Tempel-Tuttle debris during a peak Earth crossing. The analysis not only demonstrates how potential sampling strategies may improve the projections for metals or rare elements in astromining, but also benchmarks materials during low temperature (-60 F), high dessication environments as seen during atmospheric exposure. The results indicate high aluminum, magnesium and iron content for various sampled particles recovered, but generalization to the sporadic meteors expected from asteroidal sources will require future improvements in larger sampling volumes before a broad-use strategy for chemical analysis can be described. A repeat of the experimental procedure is planned for the November 1999 Leonids' shower, and various improvements for atmospheric sampling will be discussed.

  7. Three-dimensionality of space in the structure of the periodic table of chemical elements

    SciTech Connect

    Veremeichik, T. F.

    2006-07-15

    The effect of the dimension of the 3D homogeneous and isotropic Euclidean space, and the electron spin on the self-organization of the electron systems of atoms of chemical elements is considered. It is shown that the finite dimension of space creates the possibility of periodicity in the structure of an electron cloud, while the value of the dimension determines the number of stable systems of electrons at different levels of the periodic table of chemical elements and some characteristics of the systems. The conditions for the stability of systems of electrons and the electron system of an atom as a whole are considered. On the basis of the results obtained, comparison with other hierarchical systems (nanostructures and biological structures) is performed.

  8. Genetic interpretations of elemental and chemical differences in a soil chronosequence, California

    USGS Publications Warehouse

    Harden, J.W.

    1988-01-01

    Soils developed on fluvial terraces in central California have similar parent materials, climatic settings, vegetation cover and slopes but range in age from 40,000 to 3,000,000 years. The soils have chemical compositions that change systematically with increasing age. Such chemical differentiation is most likely the result of long-term weathering and mineralogical transformations that occurred since deposition of terrace fills and stabilization of the geomorphic surfaces. The changes in composition with time closely mimic other studies on mineral weathering, in which alkali and alkali-earth elements are lost more rapidly than transitional elements. The relative rates of element loss were determined by changes in element ratios over time. Net losses and gains of elements in different size fractions were monitored by their concentrations relative to Zr, the most stable constituent. Both sand and finer size fractions have lost considerable amounts of Ca, Mg, Na and K. Aluminum appears to have been lost from the sand fraction and gained in the fine fraction over a 3-million-year-time-span. Although there is no evidence for losses of Fe and Ti from sands, there is a net influx of Fe and Ti into finer fractions, probably gained from undetectable yet significant weathering of sand grains. Etching of sand grains, clay mineralogy, and microprobe analyses also indicate that the soils have undergone these chemical transformations during their formation. Mineralogical analyses also mimic other studies on mineral weathering, in which the pyroxenes weather more rapidly than hornblende, which weathers more rapidly than sphene or zircon. ?? 1988.

  9. Impact of Seminal Chemical Elements on the Oxidative Balance in Bovine Seminal Plasma and Spermatozoa

    PubMed Central

    Tvrdá, Eva; Lukáč, Norbert; Schneidgenová, Monika; Lukáčová, Jana; Szabó, Csaba; Goc, Zofia; Greń, Agnieszka; Massányi, Peter

    2013-01-01

    Mutual relationships between selected chemical elements (Na, K, Fe, Cu, Mg, and Zn), basic motility characteristics (motility and progressive motility), and markers of the oxidative balance (superoxide dismutase, catalase, glutathione, albumin, and malondialdehyde) were investigated in bovine seminal plasma and spermatozoa. Computer assisted sperm analysis was used to assess the motility parameters; mineral concentrations were determined by the voltammetric method and flame absorption spectrophotometry; antioxidants and malondialdehyde were evaluated by UV/VIS spectrophotometry. Concentrations of chemical elements in both seminal fractions were in the following descending order: Na > K > Zn > Mg > Fe > Cu. Higher amounts of all minerals and nonenzymatic antioxidants were detected in the seminal plasma (P < 0.01; P < 0.001), while higher MDA concentration and activity of enzymatic antioxidants were recorded in the cell lysates (P < 0.01; P < 0.001). Na, Fe, Cu, Mg, and Zn were positively correlated with the motility and antioxidant parameters (P < 0.05; P < 0.01; P < 0.001). Inversely, K exhibited the positive associations with malondialdehyde (P < 0.05). This study demonstrates that most chemical elements are integral components of bovine semen and are needed for the protection against oxidative stress development. PMID:26464901

  10. Impact of Seminal Chemical Elements on the Oxidative Balance in Bovine Seminal Plasma and Spermatozoa.

    PubMed

    Tvrdá, Eva; Lukáč, Norbert; Schneidgenová, Monika; Lukáčová, Jana; Szabó, Csaba; Goc, Zofia; Greń, Agnieszka; Massányi, Peter

    2013-01-01

    Mutual relationships between selected chemical elements (Na, K, Fe, Cu, Mg, and Zn), basic motility characteristics (motility and progressive motility), and markers of the oxidative balance (superoxide dismutase, catalase, glutathione, albumin, and malondialdehyde) were investigated in bovine seminal plasma and spermatozoa. Computer assisted sperm analysis was used to assess the motility parameters; mineral concentrations were determined by the voltammetric method and flame absorption spectrophotometry; antioxidants and malondialdehyde were evaluated by UV/VIS spectrophotometry. Concentrations of chemical elements in both seminal fractions were in the following descending order: Na > K > Zn > Mg > Fe > Cu. Higher amounts of all minerals and nonenzymatic antioxidants were detected in the seminal plasma (P < 0.01; P < 0.001), while higher MDA concentration and activity of enzymatic antioxidants were recorded in the cell lysates (P < 0.01; P < 0.001). Na, Fe, Cu, Mg, and Zn were positively correlated with the motility and antioxidant parameters (P < 0.05; P < 0.01; P < 0.001). Inversely, K exhibited the positive associations with malondialdehyde (P < 0.05). This study demonstrates that most chemical elements are integral components of bovine semen and are needed for the protection against oxidative stress development. PMID:26464901

  11. Neutron Capture Elements in the Open Cluster Chemical Abundance & Mapping (OCCAM) Survey

    NASA Astrophysics Data System (ADS)

    O'Connell, Julia; Frinchaboy, Peter M.; Shetrone, Matthew D.; Majewski, Steven R.; Zasowski, Gail; Hearty, Fred R.

    2016-01-01

    The Open Cluster Chemical Abundance & Mapping (OCCAM) survey is a systematic survey of Galactic open clusters using data primarily from the SDSS-III/APOGEE-1 survey. The high-resolution (R=22,500), near-infrared (H-band) APOGEE-1 survey allows for cluster membership probability determination and analysis of light and iron-peak elements. Neutron capture elements, however, prove to be elusive in the IR region covered by APOGEE. In an effort to fully study detailed Galactic chemical evolution, we conducted a high resolution (R~60,000) spectroscopic abundance analysis of neutron capture elements for OCCAM clusters in the optical regime to complement the APOGEE results. We present results for ten open clusters using data obtained at McDonald Observatory with the 2.1m Otto Struve telescope and Sandiford Echelle Spectrograph. We see abundance trends for Ba II, La II and Eu II that are consistent with Galactic abundance patterns for these elements. Ce II appears to be slightly enhanced in all program stars with a median value of ~0.1 dex and a spread of 0.5 dex for the entire sample.

  12. Origins of light trans-Fe and r-process elements deduced from Galactic chemical evolution

    NASA Astrophysics Data System (ADS)

    Ishimaru, Yuhri; Arao, Sachie; Wanajo, Shinya; Prantzos, Nicolas

    2014-09-01

    Compact binary mergers are suggested to be the major site of the r-process elements by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however, that estimated long lifetimes of compact binaries are in conflict with the presence of large scatters in r-process elements of very metal-poor stars (MPS). To resolve this problem, we examine the role of compact binary mergers in the early Galactic chemical evolution on the assumption that our Galactic halo was formed from clusterings of sub-halos. We find that star-to-star scatters of [r/Fe] in MPS can be well explained with this scenario. Observations of MPS also show large enhancement of Sr relative to Ba, suggesting a distinct site of light trans-Fe elements. Recent nucleosynthesis studies show that electron-capture supernovae (ECSNe) can produce heavy elements up to Zr (Wanajo et al. 2011). Using our inhomogeneous chemical evolution model, we discuss that ECSNe can explain observed enhancement of Zn in MPS as well as of Sr, Y, and Zr.

  13. Neutron interrogation to identify chemical elements with an ion-tube neutron source (INS)

    SciTech Connect

    Alvarez, R.A.; Dougan, A.D.; Rowland, M.R.; Wang, T.F.

    1994-04-07

    A non-destructive analysis technique using a portable, electric ion-tube neutron source (INS) and gamma ray detector has been used to identify the key constituent elements in a number of sealed munitions, and from the elemental makeup, infer the types of agent within each. The high energy (14 MeV) and pulsed character of the neutron flux from an INS provide a method of measuring, quantitatively, the oxygen, carbon, and fluorine content of materials in closed containers, as well as the other constituents that can be measured with low-energy neutron probes. The broad range of elements that can be quantitatively measured with INS-based instruments provides a capability of verifying common munition fills; it provides the greatest specificity of any portable neutron-based technique for determining the full matrix of chemical elements in completely unrestricted sample scenarios. The specific capability of quantifying the carbon and oxygen content of materials should lead to a fast screening technique which, can discriminate very quickly between high-explosive and chemical agent-filled containers.

  14. Chemical Weathering of Black Shales and Rare Earth Element Composition of Surface Waters and Groundwater

    NASA Astrophysics Data System (ADS)

    Hannigan, R. E.; Johannesson, K. H.

    2001-05-01

    Weathering processes dominate the dissolved and suspended loads of most of the world's major rivers. Among sedimentary rocks, black shales are particularly sensitive to chemical weathering. Therefore, shale systems are useful for investigating the partitioning of chemical elements during chemical weathering. Recent studies, such as those by Peucker-Ehrenbrink, Ravizza and others, link chemical weathering of black shales to changes in marine isotopic composition. Rare earth elements (REE) have a unique chemistry and are ideal for such tracer studies. We explored the effect of modern chemical weathering of black shales on the hydrochemistry of surface and groundwaters in the Mohawk Valley of New York State. This region provides an ideal site for the investigation of trace element remobilization during the chemical weathering of black shales. In this region, surface and groundwaters, in intimate contact with black shales and have high dissolved metal concentrations presumably due to water-rock interactions. The extent to which the dissolved REE composition of the surface and ground waters retains the rock signature is, in someway related to the length of time that the water remains in contact with the rock. We compared the REE compositions of surface and groundwaters in areas draining black shale to those of waters draining regions of dolostone-limestone to explore the extent of metal release due to chemical weathering. Shale normalized REE patterns for stream waters exhibit slight heavy REE enrichments and, at some locations, LREE depletion. REE patterns of the waters normalized to their respective sediments show some LREE depletion. However, waters associated with the Little Falls dolomite show fractionation predominantly enriched in the heavy REEs. Differences between the black shale sites, recorded as light REE depletion and/or middle REE enrichment, may be related to the discharge of the streams and the total dissolved solids. The dissolved REE chemistry of

  15. Advanced radiometric complex for detection of radioactive release from Siberian chemical combine

    NASA Astrophysics Data System (ADS)

    Kolotkov, Gennady A.; Penin, Sergei T.

    2015-11-01

    The paper states limited availability of the use of the automated radiation situation monitoring system and proposes radiometric complex as more reliable system in the case of an accidental release of the Siberian Chemical Enterprises.

  16. Migration of chemical elements in food chains and ontogeny phases of meadow moth in the remote migration of butterflies

    NASA Astrophysics Data System (ADS)

    Knorr, I. B.; Naumova, E. N.; Trounova, V. A.; Zolotarev, K. V.

    1998-02-01

    To study the complex problem of the remote migrations of insects SR XRF analysis seems to be most promising. It provides fast and exact determination of elemental composition of biosamples. The presence-absence of "marking" elements and groups of elements allows one to identify geographical populations (origin) of insects. This work is based on the planned and specially performed laboratory experiments which should answer the questions on assimilation of different chemical elements, migration of these elements atontogeny phases and accumulation or the release of some elements at the final developmental stages.

  17. Determination of radioactive elements and heavy metals in sediments and soil from domestic water sources in northern peninsular Malaysia.

    PubMed

    Muhammad, Bashir G; Jaafar, Mohammad Suhaimi; Abdul Rahman, Azhar; Ingawa, Farouk Abdulrasheed

    2012-08-01

    Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public. PMID:21901308

  18. Viscoelastic deformation of lunar impact basins: Implications for heterogeneity in the deep crustal paleo-thermal state and radioactive element concentration

    NASA Astrophysics Data System (ADS)

    Kamata, Shunichi; Sugita, Seiji; Abe, Yutaka; Ishihara, Yoshiaki; Harada, Yuji; Morota, Tomokatsu; Namiki, Noriyuki; Iwata, Takahiro; Hanada, Hideo; Araki, Hiroshi; Matsumoto, Koji; Tajika, Eiichi

    2013-03-01

    Diverse geological characteristics found for the three major lunar provinces (i.e., the Feldspathic Highlands Terrane (FHT), the South Pole-Aitken Terrane (SPAT), and the Procerallum KREEP Terrane (PKT)) strongly suggest their distinctly different thermal histories. Quantitative differences among these provinces in their early thermal histories and crustal radioactive element concentrations, however, are highly unknown. One of the few observables that retain a record of the ancient lunar thermal structure is the viscoelastic state of impact basins. This study investigates the long-term evolution of basin structures using global lunar gravity field data obtained by Kaguya tracking and derives constraints for (1) the paleo-thermal state of impact basins and for (2) crustal column-averaged radioactive element concentrations for each province. Our calculation results indicate that impact basins in the central anorthositic region of the FHT (i.e., the FHT-An) require a very cold interior ( dT / dr ≤ 20 K km - 1 on the surface). This result strongly suggests that the deep portion of the thick farside highlands crust is highly depleted in radioactive elements (Th ≤ 0.5 ppm), indicating that the Th-rich SPA basin floor crust is clearly different from the lower crust underneath the FHT-An and cannot be accounted for by simple exposure of the lower crust. Our analysis also indicates that the observed basin structure allows as high as ˜ 6 ppm of column-averaged Th concentration in the crust inside the PKT. These results indicate that radioactive element concentrations deep in the crust probably vary greatly region by region, similarly to those observed on the surface.

  19. Methods for chemical recovery of non-carrier-added radioactive tin from irradiated intermetallic Ti-Sb targets

    DOEpatents

    Lapshina, Elena V.; Zhuikov, Boris L.; Srivastava, Suresh C.; Ermolaev, Stanislav V.; Togaeva, Natalia R.

    2012-01-17

    The invention provides a method of chemical recovery of no-carrier-added radioactive tin (NCA radiotin) from intermetallide TiSb irradiated with accelerated charged particles. An irradiated sample of TiSb can be dissolved in acidic solutions. Antimony can be removed from the solution by extraction with dibutyl ether. Titanium in the form of peroxide can be separated from tin using chromatography on strong anion-exchange resin. In another embodiment NCA radiotin can be separated from iodide solution containing titanium by extraction with benzene, toluene or chloroform. NCA radiotin can be finally purified from the remaining antimony and other impurities using chromatography on silica gel. NCA tin-117m can be obtained from this process. NCA tin-117m can be used for labeling organic compounds and biological objects to be applied in medicine for imaging and therapy of various diseases.

  20. Chemical species of metallic elements in the aquatic environment of an ex-mining catchment.

    PubMed

    Ashraf, Muhammad Aqeel; Ahmad, Mushtaq; Akib, Shatirah; Balkhair, Khaled S; Abu Bakar, Nor Kartini

    2014-08-01

    This study was conducted to investigate the chemical speciation of dissolved and particulate elements (lead, zinc, copper, chromium, arsenic, and tin) in the mining wastewater of a former tin-mining catchment. The speciation patterns of dissolved elements were estimated by an adsorptive stripping voltammeter (ASV), while particulate elements were analyzed by using a newly developed sequential-extraction leaching procedure. The procedure has been operationally defined among five host fractions, namely exchangeable, carbonate, reducible, organic bound, and residual fractions. A total of six elements (lead, zinc, copper, chromium, arsenic, and tin) were analyzed in thirty samples at ten locations (P1-P10), with three samples taken from each of the ten locations, to get the average value from the former tin-mining catchment. The results showed that the heavy metal pollutions in locations P4 and P8 were more severe than in other sampling sites, especially tin and lead pollution. In the water samples from locations P4 and P8, both the total contents and the most dangerous non-residual fractions of tin and lead were extremely high. More than 90% of the total concentrations of arsenic and chromium existed in the residual fraction. Concentrations of copper and zinc mainly occurred in the residual fraction (more than 60%), while lead and tin presented mostly in the non-residual fractions in surface water. For all of the six dissolved elements, the less-labile species formed the predominant fraction in their speciation patterns. The speciation patterns of particulate elements showed that most of the concentrations of zinc, copper, chromium, and arsenic were found in the reducible fraction; whereas lead and tin were mainly associated with the organic fraction. PMID:25306787

  1. The General Laws of Chemical Elements Composition Dynamics in the Biosphere

    NASA Astrophysics Data System (ADS)

    Korzh, Vyacheslav D.

    2013-04-01

    The key point of investigation of the specificity of the biosphere elemental composition formation is determination of patterns of redistribution of elemental average concentrations among various phases, like solid - liquid ( the lithosphere - the hydrosphere), which occurs as a result of a global continuous processing of inert matter by living substances. Our task here is to investigate this process in the system "lithosphere - hydrosphere" in view of the integrated involvement of living material in it. This process is most active in biogeochemical barriers, i.e. in places of "the life condensation" and runs under a nonlinear regularity that has been unknown before. It is established that this process results in a general relative increase in concentrations of chemical elements in the solid phase in proportion as their prevalence in the environment is reduced. This process running in various natural systems has practically the same parameter of nonlinearity (v) approximately equal to 0.7. For proto-lithosphere -"living material" - soil v = 0.75. For river - "living material" - ocean v = 0.67. For the contemporary factual awareness level these estimations of nonlinearity indices are practically negligible. Hence, it is for the first time that the existence of a universal constant of nonlinearity of elemental composition evolution in the biosphere has been proved and its quantitative evaluation has been made. REFERENCES 1. Korzh V.D. 1974. Some general laws governing the turnover of substance within the ocean-atmosphere-continent-ocean cycle. // Journal de Recherches Atmospheriques. Vol. 8. P. 653-660. 2. Korzh V.D. 2008. The general laws in the formation of the elemental composition of the Hydrosphere and Biosphere.// J. Ecologica, Vol. XV, P. 13-21. 3. Korzh V.D. 2012. Determination of general laws of elemental composition in Hydrosphere // Water: chemistry & ecology, Journal of water science and its practical application. # 1, P.56-62.

  2. The History and Use of Our Earth's Chemical Elements: A Reference Guide (by Robert E. Krebs)

    NASA Astrophysics Data System (ADS)

    Bracken, Reviewed By Jeffrey D.

    1999-04-01

    Greenwood Press: Westport, CT, 1998. 282 pp + 25 pp glossary + 37 pp index. 15.9 x 24.1 cm. ISBN 0-313-30123-9. $39.95. This book is an excellent resource for chemical educators at the high school and college levels. The format of the text is consistent and the writing style is clear and concise, making it ideally suited for student use also. The first three chapters serve to introduce the reader to a brief history of chemistry, early models of the atom, and the development of the periodic table. Names of the contributing scientists are mentioned whenever necessary, but the overall purpose of these introductory chapters is simply to lay a foundation for the subsequent seven chapters. A complete glossary of important scientific terms mentioned in the text should allow beginning students to use this book without feeling overwhelmed. Each entry for the 112 elements contains the following information: elemental symbol, atomic number, period, common valence, atomic weight, natural state, common isotopes, properties, characteristics, abundance, natural sources, history, common uses and compounds, and safety hazards. This information is well organized, with clear headings and separate sections making the book extremely user-friendly. Readers can easily obtain the information they desire without having to skim the full entry for a chosen element. One very nice feature of this book is that the elements entries are arranged by their locations in the periodic table. For example, chapter 4 contains the alkali metals and alkaline earth metals. This organizational scheme allows one to quickly see the patterns and trends within groups of elements. This format is significantly better than arranging the elements in alphabetical order, which places the entry for sodium far removed from the entries for lithium and potassium. I would highly recommend this book to high school teachers and college chemistry professors. It is well written and is an excellent source of information for

  3. In-situ, nondestructive identification of chemical elements by means of portable EDXRF spectrometer

    SciTech Connect

    Fiorini, C.; Longoni, A.

    1999-12-01

    The performances of a new portable EDXRF (Energy Dispersive X-ray Fluorescence) Spectrometer designed for in-situ, non-destructive identification of chemical elements in materials are here described. The instrument, based on a Silicon Drift Detector cooled by a Peltier element, does not require a liquid nitrogen cooling system. The energy resolution of the spectrometer is typically 155 eV FWHM at 6 keV at a temperature of about {minus}8 C and the peak to valley ratio is better than 10,000. The paper reports on the most significant results recently obtained, by using a new version of the Silicon Drift Detector, in measurements carried out on-the-field on samples of different materials. The results of the first quantitative analyses of metal alloys carried out with this instrument are also presented.

  4. Chemical fractionation of siderophile elements in impactites from Australian meteorite craters

    NASA Technical Reports Server (NTRS)

    Attrep, A., Jr.; Orth, C. J.; Quintana, L. R.; Shoemaker, C. S.; Shoemaker, E. M.; Taylor, S. R.

    1991-01-01

    The abundance pattern of siderophile elements in terrestrial and lunar impact melt rocks was used extensively to infer the nature of the impacting projectiles. An implicit assumption made is that the siderophile abundance ratios of the projectiles are approximately preserved during mixing of the projectile constituents with the impact melts. As this mixture occurs during flow of strongly shocked materials at high temperatures, however there are grounds for suspecting that the underlying assumption is not always valid. In particular, fractionation of the melted and partly vaporized material of the projectile might be expected because of differences in volatility, solubility in silicate melts, and other characteristics of the constituent elements. Impactites from craters with associated meteorites offer special opportunities to test the assumptions on which projectile identifications are based and to study chemical fractionation that occurred during the impact process.

  5. Multi-element analysis of manganese nodules by atomic absorption spectrometry without chemical separation

    USGS Publications Warehouse

    Kane, J.S.; Harnly, J.M.

    1982-01-01

    Five manganese nodules, including the USGS reference nodules A-1 and P-1, were analyzed for Co, Cu, Fe, K, Mg, Mn, Na, Ni and Zn without prior chemical separation by using a simultaneous multi-element atomic absorption spectrometer with an air-cetylene flame. The nodules were prepared in three digestion matrices. One of these solutions was measured using sixteen different combinations of burner height and air/acetylene ratios. Results for A-1 and P-1 are compared to recommended values and results for all nodules are compared to those obtained with an inductively coupled plasma. The elements Co, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn are simultaneously determined with a composite recovery for all elements of 100 ?? 7%, independent of the digestion matrices, heights in the flame, or flame stoichiometries examined. Individual recoveries for Co, K, and Ni are considerably poorer in two digests than this composite figure, however. The optimum individual recoveries of 100 ?? 5% and imprecisions of 1-4%, except for zinc, are obtained when Co, K, Mn, Na and Ni are determined simultaneously in a concentrated digest, and in another analytical sequence, when Cu, Fe, Mg, Mn and Zn are measured simultaneously after dilution. Determination of manganese is equally accurate in the two sequences; its measurement in both assures internal consistency between the two measurement sequences. This approach improves analytical efficiency over that for conventional atomic absorption methods, while minimizing loss of accuracy or precision for individual elements. ?? 1982.

  6. Method and apparatus for mapping the distribution of chemical elements in an extended medium

    NASA Technical Reports Server (NTRS)

    Evans, L. G.; Trombka, J. I. (Inventor)

    1984-01-01

    Contaminants in an extended medium such as the wall of a building are mapped by locating neutron excitation source on one side of the wall and a gamma ray spectrometer, including a gamma ray detector on the opposite side of the wall facing the excitation source. The source and detector are moved in unison in discrete steps over opposing wall surfaces so as to determine the chemical composition of the elements in a hemispheric region of the wall adjacent the detector with the radius of the region being substantially that of the mean free path distance of gamma rays emitted from elements interacting with neutrons on the detector side of the wall. The source and detector are reversed for relatively thick walls for mapping the distribution of elements on the other side of the wall thickness. The output of the detector is fed to a multichannel pulse height analyzer where the intensity of the various gamma ray spectral lines are indicated relative to a dominant constituent element such as silicon. Resolution of anomalies such as the presence of voids and/or determining the bulk density of the medium is achieved by substituting a gamma ray source technique is also applied to metal alloys, such as iron alloys, in either the solid or molten state.

  7. Atom-scale depth localization of biologically important chemical elements in molecular layers.

    PubMed

    Schneck, Emanuel; Scoppola, Ernesto; Drnec, Jakub; Mocuta, Cristian; Felici, Roberto; Novikov, Dmitri; Fragneto, Giovanna; Daillant, Jean

    2016-08-23

    In nature, biomolecules are often organized as functional thin layers in interfacial architectures, the most prominent examples being biological membranes. Biomolecular layers play also important roles in context with biotechnological surfaces, for instance, when they are the result of adsorption processes. For the understanding of many biological or biotechnologically relevant phenomena, detailed structural insight into the involved biomolecular layers is required. Here, we use standing-wave X-ray fluorescence (SWXF) to localize chemical elements in solid-supported lipid and protein layers with near-Ångstrom precision. The technique complements traditional specular reflectometry experiments that merely yield the layers' global density profiles. While earlier work mostly focused on relatively heavy elements, typically metal ions, we show that it is also possible to determine the position of the comparatively light elements S and P, which are found in the most abundant classes of biomolecules and are therefore particularly important. With that, we overcome the need of artificial heavy atom labels, the main obstacle to a broader application of high-resolution SWXF in the fields of biology and soft matter. This work may thus constitute the basis for the label-free, element-specific structural investigation of complex biomolecular layers and biological surfaces. PMID:27503887

  8. Atom-scale depth localization of biologically important chemical elements in molecular layers

    PubMed Central

    Schneck, Emanuel; Scoppola, Ernesto; Drnec, Jakub; Mocuta, Cristian; Felici, Roberto; Novikov, Dmitri; Fragneto, Giovanna; Daillant, Jean

    2016-01-01

    In nature, biomolecules are often organized as functional thin layers in interfacial architectures, the most prominent examples being biological membranes. Biomolecular layers play also important roles in context with biotechnological surfaces, for instance, when they are the result of adsorption processes. For the understanding of many biological or biotechnologically relevant phenomena, detailed structural insight into the involved biomolecular layers is required. Here, we use standing-wave X-ray fluorescence (SWXF) to localize chemical elements in solid-supported lipid and protein layers with near-Ångstrom precision. The technique complements traditional specular reflectometry experiments that merely yield the layers’ global density profiles. While earlier work mostly focused on relatively heavy elements, typically metal ions, we show that it is also possible to determine the position of the comparatively light elements S and P, which are found in the most abundant classes of biomolecules and are therefore particularly important. With that, we overcome the need of artificial heavy atom labels, the main obstacle to a broader application of high-resolution SWXF in the fields of biology and soft matter. This work may thus constitute the basis for the label-free, element-specific structural investigation of complex biomolecular layers and biological surfaces. PMID:27503887

  9. Numerical values of the surface free energies of solid chemical elements

    NASA Astrophysics Data System (ADS)

    Mezey, L. Z.; Giber, J.

    1984-10-01

    The knowledge of the surface free energies γ {i/o}of solid chemical elements is necessary in many practically important subjects. The description of the quantities γ {i/o}(more correctly termed as the surface free enthalpies) is a part of a new “complex calculation of surface segregation” (CCSS) method, proposed by the authors. Here the applicability of a “standard table” of the values of γ {/i o }, obtained in that part of CCSS is shown by comparing the calculated values of γ {/i o }with several recently published experimental results.

  10. PFO-CFO Hypothesis of Solar System Formation: the presolar star as the only source of chemical elements for the Solar System

    NASA Astrophysics Data System (ADS)

    Kadyshevich, E. A.; Ostrovskii, V. E.

    2013-09-01

    According to the PFO-CFO Hypothesis of Solar System (SS) Formation [1, 2], the stellar radiation zone (RZ) contains an unstructured neutron (n0) - proton (p0) substance. Stars emit pico-drops (p-ds) of this substance from the RZ-bottom layer into the space with protuberances and, under a definite critical condition, with the imploded RZ material. The n0/p0 ratios of these p-ds increase in time. The nonradioactive p-ds transform into stable atoms right away, radioactive ones do this as a result of radioactive decays. All chemical isotopes of the SS are formed by this mechanism from the presolar star substance. This process is detailed in [2] and in another presentation of these authors. Here: (1) the sequences of transformations of radioactive p-ds from the moments of their emissions to formation of stable atoms are studied, and the p vs. n0/p0 dependence for 160 isotopes of 60 elements is plotted; for this aim, the available Tables [3] that give the potential parental nuclides for each known isotope and characteristics of each radiation-chemical decay are used; (2) the Fraunhofer lines and SOHO measurements characterizing the photospheric gas and solar wind compositions, respectively, are generalized and the data are also plotted as p vs. n0/p0. The results confirm the PFO-CFO Hypothesis and force us to conclude that the Sun lived more than 90% of its life and that, in the astronomic time scale, the harmful radiation zone destruction is not far off.

  11. Methods of chemical analysis for organic waste constituents in radioactive materials: A literature review

    SciTech Connect

    Clauss, S.A.; Bean, R.M.

    1993-02-01

    Most of the waste generated during the production of defense materials at Hanford is presently stored in 177 underground tanks. Because of the many waste treatment processes used at Hanford, the operations conducted to move and consolidate the waste, and the long-term storage conditions at elevated temperatures and radiolytic conditions, little is known about most of the organic constituents in the tanks. Organics are a factor in the production of hydrogen from storage tank 101-SY and represent an unresolved safety question in the case of tanks containing high organic carbon content. In preparation for activities that will lead to the characterization of organic components in Hanford waste storage tanks, a thorough search of the literature has been conducted to identify those procedures that have been found useful for identifying and quantifying organic components in radioactive matrices. The information is to be used in the planning of method development activities needed to characterize the organics in tank wastes and will prevent duplication of effort in the development of needed methods.

  12. Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils.

    PubMed

    Thørring, H; Skuterud, L; Steinnes, E

    2014-08-01

    The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ∼10 000 L m(-2) per column, results indicate that acidic precipitation increased the mobility of (134)Cs added during the experiment. However, depth distribution of already present Chernobyl fallout (137)Cs was not significantly affected by the chemical composition of precipitation. PMID:24704765

  13. Radioactivity dosage evaluation of Brazilian ornamental granitic rocks based on chemical data, with mineralogical and lithological characterization

    NASA Astrophysics Data System (ADS)

    Salas, Humberto Terrazas; Nalini, Hermínio Arias; Mendes, Júlio César

    2006-02-01

    One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry, and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite, and zircon. Chemical analysis revealed uranium concentrations ≤30 ppm and thorium ≤130 ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for samples, of floor tiles in a standard room, with total concentration of uranium and thorium greater than 60 ppm. On the basis of calculations of 232 Th, 40 K, and 226 Ra from analysis of Th, K, and U, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.

  14. Measurements of the stratospheric plume from the Mount St. Helens eruption: radioactivity and chemical composition

    SciTech Connect

    Leifer, R.; Hinchliffe, L.; Fisenne, I.; Franklin, H.; Knutson, E.; Olden, M.; Sedlacek, W.; Mroz, E.; Cahill, T.

    1981-11-20

    Gas measurements made in the stratospheric plume from the eruption of Mount St. Helens on 18 May 1980 were not consistent with a reported large injection of radon-222 into the atmosphere. No enrichment in the volatile element polonium was found in filter samples, and the ratio of polonium-210 to lead-210 was not different from background values. Data obtained with an experimental impactor, flown shortly after the eruption, showed an increase of 10/sup 3/ in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption.

  15. Measurements of the stratospheric plume from the mount st. Helens eruption: radioactivity and chemical composition.

    PubMed

    Leifer, R; Hinchliffe, L; Fisenne, I; Franklin, H; Knutson, E; Olden, M; Sedlacek, W; Mroz, E; Cahill, T

    1981-11-20

    Gas measurements made in the stratospheric plume from the eruption of Mount St. Helens on 18 May 1980 were not consistent with a reported large injection of radon-222 into the atmosphere. No enrichment in the volatile element polonium was found in filter samples, and the ratio of polonium-210 to lead-210 was not different from background values. Data obtained with an experimental impactor, flown shortly after the eruption, showed an increase of 10(3) in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption. PMID:17782443

  16. The Detailed Chemical Properties of M31 Star Clusters. I. Fe, Alpha and Light Elements

    NASA Astrophysics Data System (ADS)

    Colucci, Janet E.; Bernstein, Rebecca A.; Cohen, Judith G.

    2014-12-01

    We present ages, [Fe/H] and abundances of the α elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters (GCs) in M31, which were obtained from high-resolution, high signal-to-noise ratio >60 echelle spectra of their integrated light (IL). All abundances and ages are obtained using our original technique for high-resolution IL abundance analysis of GCs. This sample provides a never before seen picture of the chemical history of M31. The GCs are dispersed throughout the inner and outer halo, from 2.5 kpc < R M31 < 117 kpc. We find a range of [Fe/H] within 20 kpc of the center of M31, and a constant [Fe/H] ~ - 1.6 for the outer halo clusters. We find evidence for at least one massive GC in M31 with an age between 1 and 5 Gyr. The α-element ratios are generally similar to the Milky Way GC and field star ratios. We also find chemical evidence for a late-time accretion origin for at least one cluster, which has a different abundance pattern than other clusters at similar metallicity. We find evidence for star-to-star abundance variations in Mg, Na, and Al in the GCs in our sample, and find correlations of Ca, Mg, Na, and possibly Al abundance ratios with cluster luminosity and velocity dispersion, which can potentially be used to constrain GC self-enrichment scenarios. Data presented here were obtained with the HIRES echelle spectrograph on the Keck I telescope. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  17. THE DETAILED CHEMICAL PROPERTIES OF M31 STAR CLUSTERS. I. Fe, ALPHA AND LIGHT ELEMENTS

    SciTech Connect

    Colucci, Janet E.; Bernstein, Rebecca A.; Cohen, Judith G.

    2014-12-20

    We present ages, [Fe/H] and abundances of the α elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters (GCs) in M31, which were obtained from high-resolution, high signal-to-noise ratio >60 echelle spectra of their integrated light (IL). All abundances and ages are obtained using our original technique for high-resolution IL abundance analysis of GCs. This sample provides a never before seen picture of the chemical history of M31. The GCs are dispersed throughout the inner and outer halo, from 2.5 kpc < R {sub M31} < 117 kpc. We find a range of [Fe/H] within 20 kpc of the center of M31, and a constant [Fe/H] ∼ – 1.6 for the outer halo clusters. We find evidence for at least one massive GC in M31 with an age between 1 and 5 Gyr. The α-element ratios are generally similar to the Milky Way GC and field star ratios. We also find chemical evidence for a late-time accretion origin for at least one cluster, which has a different abundance pattern than other clusters at similar metallicity. We find evidence for star-to-star abundance variations in Mg, Na, and Al in the GCs in our sample, and find correlations of Ca, Mg, Na, and possibly Al abundance ratios with cluster luminosity and velocity dispersion, which can potentially be used to constrain GC self-enrichment scenarios. Data presented here were obtained with the HIRES echelle spectrograph on the Keck I telescope.

  18. The age of the Galactic disk - Inflow, chemical evolution, astration, and radioactivity

    NASA Technical Reports Server (NTRS)

    Clayton, Donald D.

    1989-01-01

    Theoretical models of Galactic evolution and observational data on the age of the Galaxy are compared, with a focus on recent results. Topics addressed include the infall of material and its effects on the age-metallicity relation, the distribution of metallicity, the present gas fraction and metallicity, and the age spectrum of interstellar nuclei; the chemical evolution of the solar neighborhood; the key results of nuclear cosmochronology; and astration effects on Galactic age. It is found that both nuclear cosmochronology and detailed stellar and Galactic evolution models tend to support an age of 12-16 Gyr.

  19. The fate of minor alkali elements in the chemical evolution of salt lakes

    PubMed Central

    2011-01-01

    Alkaline earth elements and alkali metals (Mg, Ca, Na and K) play an important role in the geochemical evolution of saline lakes as the final brine type is defined by the abundance of these elements. The role of major ions in brine evolution has been studied in great detail, but little has been done to investigate the behaviour of minor alkali elements in these systems despite their similar chemical affinities to the major cations. We have examined three major anionic brine types, chloride, sulphate, and bicarbonate-carbonate, in fifteen lakes in North America and Antarctica to determine the geochemical behaviour of lithium, rubidium, strontium, and barium. Lithium and rubidium are largely conservative in all water types, and their concentrations are the result of long-term solute input and concentration through evaporation and/or sublimation. Strontium and barium behaviours vary with anionic brine type. Strontium can be removed in sulphate and carbonate-rich lakes by the precipitation of carbonate minerals. Barium may be removed in chloride and sulphate brines by either the precipitation of barite and perhaps biological uptake. PMID:21992434

  20. Behaviour of chemical elements during weathering of pyroclastic rocks, Hong Kong.

    PubMed

    Malpas, J; Duzgoren-Aydin, N S; Aydin, A

    2001-05-01

    The behaviour of whole-rock major, trace and rare earth elements (REE) during weathering under subtropical conditions is examined along a profile developed over crystal--vitric tuffs with eutaxitic texture. The intensity of weathering within the profile varies erratically, indicating weathering processes operate over different scales. Quartz, K-feldspar, plagioclase and biotite are the main primary minerals, whereas clays, sesquioxides, sericite and chlorite are the alteration products. Kaolinite, halloysite and illite-mica are the dominant clay minerals present in significantly varying proportions. Two competing processes, namely leaching and fixation, are the main regulators of variations in mostly major and some trace element concentrations along the profile. In general, as the intensity of weathering increases, Ca, Na, K, Sr +/- Si decrease, while Fe, Ti, Al and loss of ignition (LOI) increase. Likewise, the intensity of negative Eu-anomaly decreases while the intensity of negative Ce-anomaly and the La/Lu and Sm/Nd ratios increases. In detail, however, the behaviour of chemical elements cannot be solely explained in terms of the degree of weathering. This study makes it clearly evident that the type and abundance of sesquioxides and clay minerals can significantly modify the geochemical signatures of weathering processes. PMID:11392752

  1. The fate of minor alkali elements in the chemical evolution of salt lakes.

    PubMed

    Witherow, Rebecca A; Lyons, W Berry

    2011-01-01

    Alkaline earth elements and alkali metals (Mg, Ca, Na and K) play an important role in the geochemical evolution of saline lakes as the final brine type is defined by the abundance of these elements. The role of major ions in brine evolution has been studied in great detail, but little has been done to investigate the behaviour of minor alkali elements in these systems despite their similar chemical affinities to the major cations. We have examined three major anionic brine types, chloride, sulphate, and bicarbonate-carbonate, in fifteen lakes in North America and Antarctica to determine the geochemical behaviour of lithium, rubidium, strontium, and barium. Lithium and rubidium are largely conservative in all water types, and their concentrations are the result of long-term solute input and concentration through evaporation and/or sublimation. Strontium and barium behaviours vary with anionic brine type. Strontium can be removed in sulphate and carbonate-rich lakes by the precipitation of carbonate minerals. Barium may be removed in chloride and sulphate brines by either the precipitation of barite and perhaps biological uptake. PMID:21992434

  2. Lack of chemical fractionation in major and minor elements during agglutinate formation. [in lunar soil

    NASA Technical Reports Server (NTRS)

    Hu, H.-N.; Taylor, L. A.

    1977-01-01

    Rhodes et al. (1975, 1976) and Adams et al. (1975) have reported that the agglutinate fraction of the soils on the lunar surface displays a marked enrichment in Fe, Mg, Ti, K, and La, and a depletion in Ca, Na, Al, and Eu, relative to the bulk soils. The reported investigation is concerned with a testing of the theory of chemical fractionation involving magnetic separation which was developed in connection with these findings. Soils 64421 and 71501 were sieved and the magnetic fractions separated according to the method developed by Adams and McCord (1973). Analyses of agglutinitic glass did not indicate any appreciable chemical fractionation for the major and minor elements accompanying the agglutination process. It was found that most, if not all fractionations reported can be accounted for completely by the magnetic nonagglutinate impurities in the agglutinate fraction. It is, therefore, concluded that there appears to be no reason to make use of any chemical fractionation theory, whose validity remains to be demonstrated.

  3. New evidence for chemical fractionation of radioactive xenon precursors in fission chains

    NASA Astrophysics Data System (ADS)

    Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.

    2016-04-01

    Mass-spectrometric analyses of Xe released from acid-treated U ore reveal that apparent Xe fission yields significantly deviate from the normal values. The anomalous Xe structure is attributed to chemically fractionated fission (CFF), previously observed only in materials experienced neutron bursts. The least retentive CFF-Xe isotopes, 136Xe and 134Xe, typically escape in 2:1 proportion. Xe retained in the sample is complimentarily depleted in these isotopes. This nucleochemical process allows understanding of unexplained Xe isotopic structures in several geophysical environments, which include well gasses, ancient anorthosite, some mantle rocks, as well as terrestrial atmosphere. CFF is likely responsible for the isotopic difference in Xe in the Earth's and Martian atmospheres and it is capable of explaining the relationship between two major solar system Xe carriers: the Sun and phase-Q, found in meteorites.

  4. Chemical Environment at Waste Package Surfaces in a High-Level Radioactive Waste Repository

    SciTech Connect

    Carroll, S; Alai, M; Craig, L; Gdowski, G; Hailey, P; Nguyen, Q A; Rard, J; Staggs, K; Sutton, M; Wolery, T

    2005-05-26

    We have conducted a series of deliquescence, boiling point, chemical transformation, and evaporation experiments to determine the composition of waters likely to contact waste package surfaces over the thermal history of the repository as it heats up and cools back down to ambient conditions. In the above-boiling period, brines will be characterized by high nitrate to chloride ratios that are stable to higher temperatures than previously predicted. This is clearly shown for the NaCl-KNO{sub 3} salt system in the deliquescence and boiling point experiments in this report. Our results show that additional thermodynamic data are needed in nitrate systems to accurately predict brine stability and composition due to salt deliquescence in dust deposited on waste package surfaces. Current YMP models capture dry-out conditions but not composition for NaCl-KNO{sub 3} brines, and they fail to predict dry-out conditions for NaCl-KNO{sub 3}-NaNO{sub 3} brines. Boiling point and deliquescence experiments are needed in NaCl-KNO{sub 3}-NaNO{sub 3} and NaCl-KNO{sub 3}-NaNO{sub 3}-Ca(NO{sub 3}){sub 2} systems to directly determine dry-out conditions and composition, because these salt mixtures are also predicted to control brine composition in the above-boiling period. Corrosion experiments are needed in high temperature and high NO{sub 3}:Cl brines to determine if nitrate inhibits corrosion in these concentrated brines at temperatures above 160 C. Chemical transformations appear to be important for pure calcium- and magnesium-chloride brines at temperatures greater than 120 C. This stems from a lack of acid gas volatility in NaCl/KNO{sub 3} based brines and by slow CO{sub 2}(g) diffusion in alkaline brines. This suggests that YMP corrosion models based on bulk solution experiments over the appropriate composition, temperature, and relative humidity range can be used to predict corrosion in thin brine films formed by salt deliquescence. In contrast to the above-boiling period, the

  5. Effects of chemical elements in the trophic levels of natural salt marshes.

    PubMed

    Kamiński, Piotr; Barczak, Tadeusz; Bennewicz, Janina; Jerzak, Leszek; Bogdzińska, Maria; Aleksandrowicz, Oleg; Koim-Puchowska, Beata; Szady-Grad, Małgorzata; Klawe, Jacek J; Woźniak, Alina

    2016-06-01

    The relationships between the bioaccumulation of Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Co, Cd, and Pb, acidity (pH), salinity (Ec), and organic matter content within trophic levels (water-soil-plants-invertebrates) were studied in saline environments in Poland. Environments included sodium manufactures, wastes utilization areas, dumping grounds, and agriculture cultivation, where disturbed Ca, Mg, and Fe exist and the impact of Cd and Pb is high. We found Zn, Cu, Mn, Co, and Cd accumulation in the leaves of plants and in invertebrates. Our aim was to determine the selectivity exhibited by soil for nutrients and heavy metals and to estimate whether it is important in elucidating how these metals are available for plant/animal uptake in addition to their mobility and stability within soils. We examined four ecological plant groups: trees, shrubs, minor green plants, and water macrophytes. Among invertebrates, we sampled breastplates Malacostraca, small arachnids Arachnida, diplopods Diplopoda, small insects Insecta, and snails Gastropoda. A higher level of chemical elements was found in saline polluted areas (sodium manufactures and anthropogenic sites). Soil acidity and salinity determined the bioaccumulation of free radicals in the trophic levels measured. A pH decrease caused Zn and Cd to increase in sodium manufactures and an increase in Ca, Zn, Cu, Cd, and Pb in the anthropogenic sites. pH increase also caused Na, Mg, and Fe to increase in sodium manufactures and an increase in Na, Fe, Mn, and Co in the anthropogenic sites. There was a significant correlation between these chemical elements and Ec in soils. We found significant relationships between pH and Ec, which were positive in saline areas of sodium manufactures and negative in the anthropogenic and control sites. These dependencies testify that the measurement of the selectivity of cations and their fluctuation in soils provide essential information on the affinity and binding strength in these environments. The

  6. Chemical Fixation of Trace Elements in Coal Fly Ash using Ferrous Sulfate Treatment

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Donahoe, R. J.

    2008-12-01

    Coal fired electric power plants produce 50% of the electricity consumed in the US and generate large volumes of fly ash and other coal combustion by-products (CCBs). The majority of the CCB materials are disposed of in surface impoundments and landfills located throughout the US. Fly ash contains trace elements such as As, B, Cr, Mo, Ni, Se, Sr and V which can have a negative impact on the environment due to leaching by acid rain and groundwater with time. The potential release of these toxic trace elements into the environment is a big concern for the US power industry due to the high cost involved in lining the old and existing ash disposal sites. As a result, simple and effective treatment techniques are needed to stabilize the coal combustion by-products produced by power plants in the ash disposal sites and also to increase the use of coal fly ash for beneficial purposes. This paper reports the results of batch experiments designed to chemically treat coal fly ash with ferrous sulfate solution by promoting the formation of insoluble iron oxy- hydroxide phases that immobilize the toxic trace elements. Four fly ash samples, three acidic (HA, HB and MA) and one alkaline (PD), were treated with a ferrous sulfate (FS) solution (322 ppm Fe) and a ferrous sulfate + calcium carbonate (FS+CC) solution (322 ppm Fe and 28 ppm CaCO3) at solid:liquid ratios of 1:3 and 1:30. The effectiveness of this treatment technique was evaluated by the batch sequential leaching of treated and untreated coal fly ash samples using a synthetic acid rain (SAR) solution (USEPA Method 1312B) and also by a 7-step sequential chemical extraction procedure (SCEP) to understand the mechanism of treatment. The unbuffered FS solution at the 1:30 ratio was highly successful in reducing the mobility of the oxyanionic trace elements As (24-91%), Cr (82-97%), Mo (79-100%), Se (41-87%) and V (55-100%). However, the unbuffered FS treatment failed to reduce the mobility of B, Ni and Sr for the acidic fly

  7. Chemical Elemental Distribution and Soil DNA Fingerprints Provide the Critical Evidence in Murder Case Investigation

    PubMed Central

    Concheri, Giuseppe; Bertoldi, Daniela; Polone, Elisa; Otto, Stefan; Larcher, Roberto; Squartini, Andrea

    2011-01-01

    Background The scientific contribution to the solution of crime cases, or throughout the consequent forensic trials, is a crucial aspect of the justice system. The possibility to extract meaningful information from trace amounts of samples, and to match and validate evidences with robust and unambiguous statistical tests, are the key points of such process. The present report is the authorized disclosure of an investigation, carried out by Attorney General appointment, on a murder case in northern Italy, which yielded the critical supporting evidence for the judicial trial. Methodology/Principal Findings The proportional distribution of 54 chemical elements and the bacterial community DNA fingerprints were used as signature markers to prove the similarity of two soil samples. The first soil was collected on the crime scene, along a corn field, while the second was found in trace amounts on the carpet of a car impounded from the main suspect in a distant location. The matching similarity of the two soils was proven by crossing the results of two independent techniques: a) elemental analysis via inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES) approaches, and b) amplified ribosomal DNA restriction analysis by gel electrophoresis (ARDRA). Conclusions Besides introducing the novel application of these methods to forensic disciplines, the highly accurate level of resolution observed, opens new possibilities also in the fields of soil typing and tracking, historical analyses, geochemical surveys and global land mapping. PMID:21674041

  8. Remote sensing of chemical and physical processes in the atmosphere caused by the presence of radioactive ionization source

    NASA Astrophysics Data System (ADS)

    Boyarchuk, Kirill; Tumanov, Mikhail; Karelin, Alexander

    During the years of the nuclear power industry, some large accidents occurred at the nuclear objects, and that caused enormous environmental contamination. The last accident at the Fucushima-1 power plant highlighted the need to review seriously the safety issues at the active power plants and to develop the new effective methods for remote detection and control over radioactive environmental contamination and over general geophysical situation in the areas. The main influence of the fission products on the environment is its ionisation, and therefore various detectable biological and physical processes that are caused by ions. Presence of an ionisation source within the area under study may cause significant changes of absolute humidity and, that is especially important, changes of the chemical potential of atmosphere vapours indicating presence of charged condensation centres. These effects may cause anomalies in the IR radiation emitted from the Earth surface and jumps in the chemical potentials of water vapours that may be observed by means of the satellite remote sensing by specialized equipment (works by Dimitar Ouzounov, Sergey Pulinets, e.a.). In the current study, the theoretical description is presented from positions of the molecular-kinetic condensation theory that shows significant changes of the absolute and relative humidity values in the near-earth air layer. The detailed calculations of the water vapours in atmosphere were carried out with use of detailed non-stationary kinetic model of moist atmosphere air. The processes of condensation and evaporation were effectively considered with use of reactions of neutral water molecules’ association under presence of a third particle, conversion of water molecules with an ion cluster to a more complicated cluster, and the relevant counter reactions’ splits of neutral and ion clusters.

  9. Chemical speciation of redox sensitive elements during hydrocarbon leaching in the Junggar Basin, Northwest China

    NASA Astrophysics Data System (ADS)

    Zheng, Guodong; Fu, Bihong; Takahashi, Yoshio; Kuno, Akihito; Matsuo, Motoyuki; Zhang, Jindong

    2010-11-01

    Bleaching related to seepage of petroleum fluids and subsurface migration of crude oil and natural gas can alter the chemical and mineralogical properties of rocks, while concurrently depleting hydrocarbon reservoirs. Mud volcanoes constitute one type of petroleum seepage present in several areas on the southern margin of the Junggar Basin in the Xinjiang Uygur Autonomous Region, NW China. The results of XRD, XRF, XANES, and Mössbauer spectroscopy on rock samples collected from areas affected by these mud volcanoes revealed an enrichment of certain minerals and elements, as well changes in mineralogical, molecular, or ionic carrier ("species"). After bleaching, reddish sedimentary rocks showed depletion in silica and enrichment of calcium, magnesium, manganese, and iron. Other elements, including aluminum, potassium, sodium, and titanium, were largely unchanged. Reduced iron and sulfur compounds predominated in the bleached rocks, producing changes in color from the original reddish into green, deep gray, and black. Iron and calcium were associated with carbonates, indicating carbonation of these elements during the bleaching processes. Manganese also appeared to be associated with carbonate, though not with sulfate even though sulfate was present in the bleached rocks. Alkaline conditions were apparently the dominant because reduced manganese would have been absent under acidic condition. The alteration of certain minerals, clay minerals in particular, was also observed in bleached rocks, the alteration of smectite-group minerals to chlorite and muscovite, for example. Mineralogical and geochemical changes in rocks bleached by hydrocarbon fluids could provide a better overall understanding of bleaching processes, and may have applications in surface geochemical exploitation and remote imaging.

  10. A DIFFERENTIAL CHEMICAL ELEMENT ANALYSIS OF THE METAL-POOR GLOBULAR CLUSTER NGC 6397

    SciTech Connect

    Koch, Andreas; McWilliam, Andrew E-mail: andy@obs.carnegiescience.edu

    2011-08-15

    We present chemical abundances in three red giants and two turnoff (TO) stars in the metal-poor Galactic globular cluster (GC) NGC 6397 based on spectroscopy obtained with the Magellan Inamori Kyocera Echelle high-resolution spectrograph on the Magellan 6.5 m Clay telescope. Our results are based on a line-by-line differential abundance analysis relative to the well-studied red giant Arcturus and the Galactic halo field star Hip 66815. At a mean of -2.10 {+-} 0.02 (stat.) {+-}0.07 (sys.), the differential iron abundance is in good agreement with other studies in the literature based on gf-values. As in previous differential works we find a distinct departure from ionization equilibrium in that the abundances of Fe I and Fe II differ by {approx}0.1 dex, with opposite signs for the red giant branch (RGB) and TO stars. The {alpha}-element ratios are enhanced to 0.4 (RGB) and 0.3 dex (TO), respectively, and we also confirm strong variations in the O, Na, and Al/Fe abundance ratios. Accordingly, the light-element abundance patterns in one of the red giants can be attributed to pollution by an early generation of massive Type II supernovae. TO and RGB abundances are not significantly different, with the possible exception of Mg and Ti, which are, however, amplified by the patterns in one TO star additionally belonging to this early generation of GC stars. We discuss interrelations of these light elements as a function of the GC metallicity.

  11. The chemical and microbial degradation of cellulose in the near field of a repository for radioactive wastes

    SciTech Connect

    Askarieh, M.M.; Chambers, A.V.; Daniel, F.B.D.; FitzGerald, P.L.; Holtom, G.J.; Pilkington, N.J.; Rees, J.H.

    2000-07-01

    This paper focuses on one aspect of the calculations of risk in performance assessments of the deep disposal of radioactive wastes in the UK, namely the apparent contradiction regarding the representation of microbial activity in performance assessments of the release of gases and of dissolved radionuclides. A discussion is presented of the current understanding of the microbial and chemical degradation of cellulose. The assumptions made in recent performance assessment calculations of the Nirex disposal concept are then stated. For the release of gases, it was assumed that the complete conversion of cellulosic wastes to gases by the action of microbes, was, in principle, permitted. However, concerning migration of radionuclides by the groundwater pathway, all the cellulose was assumed to be converted to complexants that could increase the solubility and decrease the sorption of radionuclides in the near field. This contradiction in the approach of the groundwater and gas pathway assessments stems from the consistent need to provide a cautious approach in the face of uncertainty about the actual evolution of microbial activity in the repository. Therefore, no credit is currently taken for possible beneficial effects of the microbial destruction of complexants, whereas the complete conversion of cellulose to gaseous products is assumed.

  12. Flow and transport modeling of liquid radioactive waste injection using data from the Siberian Chemical Plant Injection Site

    NASA Astrophysics Data System (ADS)

    Shestakov, V.; Kuvaev, A.; Lekhov, A.; Pozdniakov, S.; Rybalchenko, A.; Zubkov, A.; Davis, P.; Kalinina, E.

    2002-06-01

    The focus of our investigation was simulating pre-injection and post-injection subsurface conditions at the waste disposal site of liquid radioactive wastes at the Siberian Chemical Complex (SCC). The main environmental and human safety concern posed by this site is related to the potential radionuclide discharge into the nearby Tom River and into the existing public-water-supply well fields located 10-13 km away. Even though (within the site) the two lower injection aquifers are isolated from the upper aquifers by a relatively continuous aquitard, in terms of regional flow they represent one hydrogeologic system that is affected by injection as well as by groundwater withdrawal from the upper aquifers and groundwater discharge into the river. Groundwater flow and transport models were developed to simulate regional flow and waste migration. Even after 1,000 years, none of the simulations indicated that there is any serious potential of high-concentration contamination of water supply wells and the discharge zone. In that time frame, simulation indicated a potential for upward movement of some amounts of contaminants through the heterogeneous sandy-clay aquitard. That is why a conceptual model incorporating heterogeneity of the clay aquitard with the possibility of preferential flow via sandy windows needs to be developed. Additional field characterization of the aquitard properties should be performed along the potential contaminant migration pathways that lead to the groundwater discharge zone.

  13. Physical-chemical treatment of wastes: a way to close turnover of elements in LSS

    NASA Astrophysics Data System (ADS)

    Kudenko, Yu A.; Gribovskaya, I. V.; Zolotukhin, I. G.

    2000-05-01

    "Man-plants-physical-chemical unit" system designed for space stations or terrestrial ecohabitats to close steady-state mineral, water and gas exchange is proposed. The physical-chemical unit is to mineralize all inedible plant wastes and physiological human wastes (feces, urine, gray water) by electromagnetically activated hydrogen peroxide in an oxidation reactor. The final product is a mineralized solution containing all elements balanced for plants' requirements. The solution has been successfully used in experiments to grow wheat, beans and radish. The solution was reusable: the evaporated moisture was replenished by the phytotron condensate. Sodium salination of plants was precluded by evaporating reactor-mineralized urine to sodium saturation concentration to crystallize out NaCl which can be used as food for the crew. The remaining mineralized product was brought back for nutrition of plants. The gas composition of the reactor comprises O 2, N 2, CO 2, NH 3, H 2. At the reactor's output hydrogen and oxygen were catalyzed into water, NH 3 was converted in a water trap into NH 4 and used for nutrition of plants. A special accessory at the reactor's output may produce hydrogen peroxide from intrasystem water and gas which makes possible to close gas loops between LSS components.

  14. Physical-chemical treatment of wastes: a way to close turnover of elements in LSS.

    PubMed

    Kudenko YuA; Gribovskaya, I V; Zolotukhin, I G

    2000-05-01

    "Man-plants-physical-chemical unit" system designed for space stations or terrestrial ecohabitats to close steady-state mineral, water and gas exchange is proposed. The physical-chemical unit is to mineralize all inedible plant wastes and physiological human wastes (feces, urine, gray water) by electromagnetically activated hydrogen peroxide in an oxidation reactor. The final product is a mineralized solution containing all elements balanced for plants' requirements. The solution has been successfully used in experiments to grow wheat, beans and radish. The solution was reusable: the evaporated moisture was replenished by the phytotron condensate. Sodium salination of plants was precluded by evaporating reactor-mineralized urine to sodium saturation concentration to crystallize out NaCl which can be used as food for the crew. The remaining mineralized product was brought back for nutrition of plants. The gas composition of the reactor comprises O2, N2, CO2, NH3, H2. At the reactor's output hydrogen and oxygen were catalyzed into water, NH3 was converted in a water trap into NH4 and used for nutrition of plants. A special accessory at the reactor's output may produce hydrogen peroxide from intrasystem water and gas which makes possible to close gas loops between LSS components. PMID:11543386

  15. Guidelines for generators of hazardous chemical waste at LBL and guidelines for generators of radioactive and mixed waste at LBL. Revision 1

    SciTech Connect

    Not Available

    1991-09-01

    In part one of this document the Governing Documents and Definitions sections provide general guidelines and regulations applying to the handling of hazardous chemical wastes. The remaining sections provide details on how you can prepare your waste properly for transport and disposal. They are correlated with the steps you must take to properly prepare your waste for pickup. The purpose of the second part of this document is to provide the acceptance criteria for the transfer of radioactive and mixed waste to LBL`s Hazardous Waste Handling Facility (HWHF). These guidelines describe how you, as a generator of radioactive or mixed waste, can meet LBL`s acceptance criteria for radioactive and mixed waste.

  16. Distribution of chemical elements in attic dust and soil as reflection of lithology and anthropogenic influence in Slovenia

    NASA Astrophysics Data System (ADS)

    Sajn, R.

    2003-05-01

    The aim of this study was to establish contents and distribution of chemical elements in attic dust in Slovenia, and to define them according to geology and anthiopogenic influence. Attic dust and topsoil (0-5 cm) samples were collected in the rural area in settlements without known industry and in six largest towns in Slovenia. Analysis of 42 chemical elements was performed. For estimation of the association between elements and sampling materials the R mode factor analysis was applied. Al, Ba, Co, Ci, Fe, La, Mn, Na, Nb, Ni, Sc, Th, Ti, Y, V and Zr in attic dust reflect the natural distribution. The highest elemental contents in attic dust occur in the areas of igneous and metmoiphic rocks and of flysch formation. High contents of the elemental association Co, Ci, Fe, Mn, and Ni reflect also centuries of ferrous metallurgy. Distribution of As, Cd, Cu, Hg, Mo, Sb, Sn, Sr, Pb and Zn represents the anthropogenically introduced chemical elements. Their averages in attic dust are higher compared to topsoil. High contents of these elements are a result of historical Pb-Zn mining and smelting.

  17. Transfer of chemical elements from a contaminated estuarine sediment to river water. A leaching assay

    NASA Astrophysics Data System (ADS)

    Abreu, Manuela; Peres, Sara; Magalhães, M. Clara F.

    2014-05-01

    Wastes of a former Portuguese steel industry were deposited during 40 years on the left bank of the Coina River, which flows into the estuary of the Tagus River near Lisbon. The aim of this study was to evaluate the release of the chemical elements from the contaminated sediment to the river water. A leaching experiment (four replicates) was performed using 1.6 kg/replicate of sediment from a landfill located in the Coina River bank, forming a lagoon subject to tidal influence. River water coming from this lagoon was collected during low tide. This water (200 mL) was added to the moist sediment, contained in cylindrical reactors, and was collected after 24 h of percolation. The leaching experiments were conducted for 77 days being leachates collected at time zero, after 28, 49 and 77 days with the sediment always moist. The sediment was characterized for: pH, electric conductivity (EC), total organic carbon (TOC), extractable phosphorus and potassium, mineral nitrogen, iron from iron oxides (crystalline and non-crystalline) and manganese oxides. Multi-elemental analysis was also made by ICP-INAA. Leachates and river water were analysed for pH, EC, hydrogencarbonate and sulfatetot by titrations, chloride by potentiometry, and multi-elemental composition by ICP-MS. The sediment presented pH=7.2, EC=18.5 dS/m, TOC=147.8 g/kg, high concentrations of extractable phosphorous (62.8 mg/kg) and potassium (1236.8 mg/kg), mineral nitrogen=11.3 mg/kg. The non-crystalline fraction of iron oxides corresponds to 99% (167.5 g Fe/kg) of the total iron oxides, and manganese from manganese oxides was low (52.7 mg/kg). Sediment is considered contaminated. It contained high concentrations (g/kg) of Zn (2.9), Pb (0.9), Cr (0.59), Cu (0.16), As (0.07), Cd (0.005), and Hg (0.001), which are above Canadian values for marine sediments quality guidelines for protection of aquatic life. River water had: pH=8.2, EC=28.6 dS/m, csulfate=1.23 g/L, and [Cl-]=251.6 mg/L. The concentrations of Cd (0

  18. Yeasts associated with an abandoned mining area in Pernek and their tolerance to different chemical elements.

    PubMed

    Vadkertiová, Renáta; Molnárová, Jana; Lux, Alexander; Vaculík, Marek; Lišková, Desana

    2016-05-01

    Four plants, Cirsium arvense (creeping thistle), Equisetum arvense (field horsetail), Oxalis acetosella (wood sorrel) and Phragmites australis (common reed), which grew in an abandoned Sb-mining area in Pernek (Malé Karpaty Mts., Slovakia), were investigated for the yeast species. Yeasts were isolated from both the leaves of the plants and the soil adjacent to the plants. In total, 65 yeast cultures, belonging to 11 ascomycetous and 5 basidiomycetous yeast species, were isolated. The species most frequently isolated from both the soil and leaf samples were Trichosporon porosum, Galactomyces candidus and Candida solani, whereas Aureobasidium pullulans, Candida tsuchiyae and Sporidiobolus metaroseus were isolated exclusively from the plant leaves. All the yeast species isolated were tested for their tolerance to two heavy metals (Cd, Zn) and three metalloids (As, Sb and Si). The yeasts isolated from both the leaves and soils exhibited a high tolerance level to both As and Sb, present in elevated concentrations at the locality. Among the yeast species tested, Cryptococcus musci, a close relative to Cryptococcus humicola, was the species most tolerant to all the chemical elements tested, with the exception of Si. It grew in the presence of 200 mmol/L Zn, 200 mmol/L Cd, 60 mmol/L As and 50 mmol/L Sb, and therefore, it can be considered as a multi-tolerant species. Some of the yeast species were tolerant to the individual chemical elements. The yeast-like species Trichosporon laibachii exhibited the highest tolerance to Si of all yeasts tested, and Cryptococcus flavescens and Lindnera saturnus showed the same tolerance as Cryptococcus musci to Zn and As, respectively. The majority of the yeasts showed a notably low tolerance to Cd (not exceeded 0.5 mmol/L), which was present in small amounts in the soil. However, Candida solani, isolated from the soil, exhibited a higher tolerance to Cd (20 mmol/L) than to As (2 mmol/L). PMID:26358066

  19. Estimation of the physico-chemical parameters of materials based on rare earth elements with the application of computational model

    NASA Astrophysics Data System (ADS)

    Mamaev, K.; Obkhodsky, A.; Popov, A.

    2016-01-01

    Computational model, technique and the basic principles of operation program complex for quantum-chemical calculations of material's physico-chemical parameters with rare earth elements are discussed. The calculating system is scalable and includes CPU and GPU computational resources. Control and operation of computational jobs and also Globus Toolkit 5 software provides the possibility to join computer users in a unified system of data processing with peer-to-peer architecture. CUDA software is used to integrate graphic processors into calculation system.

  20. Sampling and analysis of chemical element concentration distribution in rock units and orebodies

    NASA Astrophysics Data System (ADS)

    Agterberg, F. P.

    2012-01-01

    Existing sampling techniques applied within known orebodies, such as sampling along mining drifts, yield element concentration values for larger blocks of ore if they are extended into their surroundings. The resulting average concentration values have relatively small "extension variance". These techniques can be used for multifractal modeling as well as ore reserve estimation approaches. Geometric probability theory can aid in local spatial covariance modeling. It provides information about increase of variability of element concentration over short distances exceeding microscopic scale. In general, the local clustering of ore crystals results in small-scale variability known as the "nugget effect". Parameters to characterize spatial covariance estimated from ore samples subjected to chemical analysis for ore reserve estimation may not be valid at local scale because of the nugget effect. The novel method of local singularity mapping applied within orebodies provides new insights into the nature of the nugget effect. Within the Pulacayo orebody, Bolivia, local singularity for zinc is linearly related with logarithmically transformed concentration value. If there is a nugget effect, moving averages resulting from covariance models or estimated by other methods that have a smoothing effect, such as kriging, can be improved by incorporating local singularities indicating local element enrichment or depletion. Although there have been many successful applications of the multifractal binomial/p model, its application within the Pulacayo orebody results in inconsistencies, indicating some shortcomings of this relatively simple approach. Local singularity analysis and universal multifractal modeling are two promising new approaches to improve upon results obtained by commonly used geostatistical techniques and use of the binomial/p model. All methods in this paper are illustrated using a single example (118 Pulacayo zinc values), and several techniques are applied to

  1. Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass

    DOEpatents

    Miller, C.M.; Nogar, N.S.

    1982-09-02

    Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

  2. Element and chemical compounds transfer in bio-crude from hydrothermal liquefaction of microalgae.

    PubMed

    Tang, Xiaohan; Zhang, Chao; Li, Zeyu; Yang, Xiaoyi

    2016-02-01

    In this study, hydrothermal liquefaction (HTL) experiments of Nannochloropsis and Spirulina were carried out at different temperatures (220-300 °C) to explore the effects of temperature on bio-crude yield and properties. The optimal temperature for bio-crude yield was around 260-280 °C. Transfers of element and chemical compounds in bio-crude were discussed in detail to deduce the reaction mechanism. The hydrogen and carbon recoveries were consistent with the results of bio-crude yields at every temperature point. The relative percentage of fatty acid in bio-crude decreased and the amine and amide increased for both microalgae with temperature rising. The N-heterocyclic compounds in bio-crude increased with temperature rising for Nannochloropsis, while decreased when temperature increased from 220 °C to 280 °C for Spirulina. Bio-crude gained at higher temperature or from microalgae with high protein content may contain high heteroatom compounds. PMID:26700753

  3. Increase in the power of lasing on atomic and ion transitions in chemical elements

    SciTech Connect

    Klimkin, V M; Sokovikov, V G

    2007-02-28

    A method for increasing the power of pulsed lasing on atomic and ion transitions in chemical elements obtained by the conversion of the UV radiation of excimer lasers in cells with metal vapours is studied. A part of UV radiation transmitted through a cell with metal vapour is used for pumping a dye solution in such a way that the cell converter with metal vapour represents a master oscillator, while the dye cell represents an amplifier. The study is performed by the example of amplification of weak spectral components of radiation from a XeCl* laser converted in mercury and barium vapours. In the amplifying stage the longitudinal pumping of the dye is used and a scheme for suppressing self-excitation is employed. It is found by selecting dyes that the alcohol solution of uranin is nearly optimal for amplification of the 546.1-nm laser line of mercury, while the best results in amplification of the 533-nm and 648.2-nm laser lines of barium were obtained by using alcohol solutions of rhodamine 6G and oxazine 17, respectively. The power of the 546.1-nm mercury line was increased by an order of magnitude, while the power of the 533-nm and 648.2-nm lines of barium - almost by a factor of twenty-five. (lasers)

  4. CHEMICAL MAPPING OF ELEMENTAL SULFUR ON PYRITE AND ARSENOPYRITE SURFACES USING NEAR-INFRARED RAMAN IMAGING MICROSCOPY. (R826189)

    EPA Science Inventory

    Abstract

    Near-infrared Raman imaging microscopy (NIRIM) was used to produce chemical images of the distribution of elemental sulfur on oxidized pyrite and arsenopyrite surfaces. Analysis using Savitsky¯Golay filtering permits an unambiguous identificati...

  5. Understanding the Idea of Chemical Elements and Their Periodic Classification in Spanish Students Aged 16-18 Years

    ERIC Educational Resources Information Center

    Franco-Mariscal, Antonio-Joaquín; Oliva-Martínez, José María; Almoraima Gil, M. L.

    2016-01-01

    The work reported here involved a comparative study regarding the understanding that high school students (16-18 years) have of the concept of chemical elements and their periodic classification. More specifically, the level of knowledge on this topic was compared before and after the completion of baccalaureate studies in a sample of Spanish…

  6. Profiling Environmental Chemicals for Activity in the Antioxidant Response Element Signaling Pathway Using a High-Throughput Screening Approach

    EPA Science Inventory

    1 ABSTRACT 2 3 BACKGROUND: Oxidative stress has been implicated in the pathogenesis of a variety 4 of diseases ranging from cancer to neurodegeneration, highlighti.ng the need to identify 5 chemicals that can induce this effect. The antioxidant response element (ARE)...

  7. A chemical-spectrochemical method for the determination of rare earth elements and thorium in cerium minerals

    USGS Publications Warehouse

    Rose, H.J., Jr.; Murata, K.J.; Carron, M.K.

    1954-01-01

    In a combined chemical-spectrochemical procedure for quantitatively determining rare earth elements in cerium minerals, cerium is determined volumetrically, a total rare earths plus thoria precipitate is separated chemically, the ceria content of the precipitate is raised to 80??0 percent by adding pure ceria, and the resulting mixture is analyzed for lanthanum, praseodymium, neodymium, samarium, gadolinium, yttrium, and thorium spectrochemically by means of the d.c. carbon arc. Spectral lines of singly ionized cerium are used as internal standard lines in the spectrochemical determination which is patterned after Fassel's procedure [1]. Results of testing the method with synthetic mixtures of rare earths and with samples of chemically analyzed cerium minerals show that the coefficient of variation for a quadruplicate determination of any element does not exceed 5??0 (excepting yttrium at concentrations less than 1 percent) and that the method is free of serious systematic error. ?? 1954.

  8. Constrained positive matrix factorization: Elemental ratios, spatial distinction, and chemical transport model source contributions

    NASA Astrophysics Data System (ADS)

    Sturtz, Timothy M.

    Source apportionment models attempt to untangle the relationship between pollution sources and the impacts at downwind receptors. Two frameworks of source apportionment models exist: source-oriented and receptor-oriented. Source based apportionment models use presumed emissions and atmospheric processes to estimate the downwind source contributions. Conversely, receptor based models leverage speciated concentration data from downwind receptors and apply statistical methods to predict source contributions. Integration of both source-oriented and receptor-oriented models could lead to a better understanding of the implications sources have on the environment and society. The research presented here investigated three different types of constraints applied to the Positive Matrix Factorization (PMF) receptor model within the framework of the Multilinear Engine (ME-2): element ratio constraints, spatial separation constraints, and chemical transport model (CTM) source attribution constraints. PM10-2.5 mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. PMF was used to explore the underlying sources of variability. Information on previously reported PM10-2.5 tire and brake wear profiles were used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Using separate data, source contributions to total fine particle carbon predicted by a CTM were incorporated into the PMF receptor model to form a receptor-oriented hybrid model. The level of influence of the CTM versus traditional PMF was

  9. Discoveries and names of heavy chemical elements: from curium to copernicium and beyond

    NASA Astrophysics Data System (ADS)

    Sobiczewski, Adam

    2011-01-01

    The present state of the synthesis and studies of the properties of heavy nuclei is shortly presented. Main attention is given to superheavy nuclei, in particular to isotopes of copernicium, the heaviest element the discovery and name of which have been approved by IUPAC, and to isotopes of the recently observed element 117. The rules used in naming newly discovered elements and recent changes in these names or these elements are discussed.

  10. Rapid low-temperature epitaxial growth using a hot-element assisted chemical vapor deposition process

    DOEpatents

    Iwancizko, Eugene; Jones, Kim M.; Crandall, Richard S.; Nelson, Brent P.; Mahan, Archie Harvin

    2001-01-01

    The invention provides a process for depositing an epitaxial layer on a crystalline substrate, comprising the steps of providing a chamber having an element capable of heating, introducing the substrate into the chamber, heating the element at a temperature sufficient to decompose a source gas, passing the source gas in contact with the element; and forming an epitaxial layer on the substrate.

  11. Development of the chemical stabilization and solidification process for the treatment of radioactive raffinate sludges at the DOE Weldon Spring Site Remedial Action Project

    SciTech Connect

    Cole, P.M.; Kakaria, V. [Morrison Knudsen Corp., Boise, ID . Environmental Enger, J.

    1996-12-31

    Chemical Solidification and Stabilization (CSS) is the mixing of chemical reagents with waste to solidify and chemically stabilize the contaminated material. The resulting product is resistant to leaching of certain contaminants. CSS treatment using Class C fly ash and Portland cement was chosen as the most feasible method for treatment of the chemically and radioactively contaminated sludge (raffinate) contained in raffinate pits on the Weldon Spring Site Remedial Action Project (WSSRAP) located outside of St. Louis, Missouri. Due to the uniqueness of the material, substantial bench-scale testing was performed on the raffinate to better understand its properties. Similarly, due to mixed results in the application of CSS treatment to radioactive materials, a pilot-scale testing facility was built to verify bench testing results and to establish and quantify design parameters for the full-scale CSS production facility. This paper discusses the development of the pilot-scale testing facility, the testing plan, and the results of the testing activities. Particular attention has been given to the applicability of the CSS treatment method and to the value of pilot-scale testing.

  12. Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese

    PubMed Central

    Thamdrup, Bo; Finster, Kai; Hansen, Jens Würgler; Bak, Friedhelm

    1993-01-01

    A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S0) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S0 was microbially disproportionated to sulfate and sulfide, as follows: 4S0 + 4H2O → SO42- + 3H2S + 2H+. Subsequent chemical reactions between the formed sulfide and the added FeOOH led to the observed precipitation of iron sulfides. Sulfate and iron sulfides were also produced when FeOOH was replaced by FeCO3. Further enrichment with manganese oxide, MnO2, instead of FeOOH yielded stable cultures which formed sulfate during concomitant reduction of MnO2 to Mn2+. Growth of small rod-shaped bacteria was observed. When incubated without MnO2, the culture did not grow but produced small amounts of SO42- and H2S at a ratio of 1:3, indicating again a disproportionation of S0. The observed microbial disproportionation of S0 only proceeds significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S0 disproportionation in the presence of FeOOH or MnO2 was high, > 104 cm-3 in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic sulfide oxidation to sulfate in anoxic sediments. PMID:16348835

  13. Monitoring the chemical vapor deposition growth of multiwalled carbon nanotubes by tapered element oscillating microbalance

    NASA Astrophysics Data System (ADS)

    Švrček, V.; Kleps, I.; Cracioniou, F.; Paillaud, J. L.; Dintzer, T.; Louis, B.; Begin, D.; Pham-Huu, C.; Ledoux, M.-J.; Le Normand, F.

    2006-05-01

    The growth of multiwalled carbon nanotubes (MWCNTs) produced by a catalytic chemical vapor deposition (CCVD) process has been monitored using a tapered element oscillating microbalance (TEOM) probe. This technique displays a high sensitivity (<1μg). Growths in the TEOM microreactor are investigated with catalytic particles (Fe, Ni) dispersed on different supports. First, high surface area Fe /Al2O3 or Fe (Ni) exchanged on zeolite powders is used. Second, growths are performed on array of nickel dots or Fe /Si-nc particles dispersed on large holes patterned on Si(100) substrates. An accurate monitoring of the early stages of growth permits a precise evaluation of the growth rates and shows substantial differences between these samples which greatly differ by the surface area. On catalysts dispersed on Si(100) the mass uptake is linear throughout the process. On high surface area catalysts, however, a saturation of the mass uptake is indifferently observed. This saturation is explained either by diffusion limitation by the growing MWCNTs or by internal diffusion through the pores or external diffusion through the grains of the catalyst. The kinetic dependence with partial pressure of the incoming C2H6:H2 gas mixture is then explored on the Fe /Al2O3 catalyst. A linear dependence of the MWCNT growth an (PC2H6/PH2)1/2 is found. A simple model is then developed that accounts for this dependence only if an associative and competitive adsorption of ethane is the rate determining step of thP overall process. These results thus bring insight to improve and control the CCVD growth kinetics of MWCNTs.P

  14. Detailed chemical composition of the open cluster IC 4651: The iron peak, α elements, and Li

    NASA Astrophysics Data System (ADS)

    Pasquini, L.; Randich, S.; Zoccali, M.; Hill, V.; Charbonnel, C.; Nordström, B.

    2004-09-01

    We present a detailed chemical analysis of 22 stars along the colour-magnitude sequence of the intermediate-age (1.7 Gyr) open cluster IC 4651, based on high-resolution, high S/N ratio spectra from UVES/VLT. IC 4651 thus becomes one of the few open clusters for which a detailed composition analysis exists for stars spanning 3.5 mag, from solar-type main-sequence stars to giants above the RGB clump. In a strict comparison with the Sun, we find for the cluster a well-defined Fe abundance of [Fe/H] = 0.10 ± 0.03 (internal errors), with a reddening E(b-y) = 0.091. We also derive abundances for the α elements Mg, Si, Ti, and Ca and find a moderate enhancement of the three former elements, in excellent agreement with the results for field stars of similar Fe abundance. Among the Fe group elements, Cr and Ni are slightly overabundant ([X/Fe] ˜ 0.05). As also observed in M 67, the Na abundance among the giants is more than 0.2 dex higher than in the dwarfs. We interpret this effect as real, and due to dredge-up of 23Na in the giants. Four turnoff stars, all fairly rapid rotators (v sin i ≥ 25 km s-1), appear to have higher [Fe/H] than the other stars; our tests show that, while a spurious enhancement of 0.1 dex can be produced by the effect of high rotation on our spectral analysis, this cannot explain the whole difference. These stars appear overabundant because we tend to overestimate their effective temperatures by forcing excitation equilibrium. Li abundances have been computed for all the stars and show a well-defined pattern: the Solar-type stars have an almost constant Li abundance, just below that of the Hyades, and the Li-dip is pronounced and well determined. Turnoff stars just above the dip have a ``cosmic'' Li abundance, but within a very small range of magnitudes (0.25 mag) higher on the turnoff, the Li level drops by more than a factor 10. This cannot be due just to dilution; rather some extra mixing is required. Among the giants, two probable clump

  15. Reconstruction of centennial-scale fluxes of chemical elements in the Australian coastal environment using seagrass archives.

    PubMed

    Serrano, Oscar; Davis, Grace; Lavery, Paul S; Duarte, Carlos M; Martinez-Cortizas, Antonio; Mateo, Miguel Angel; Masqué, Pere; Arias-Ortiz, Ariane; Rozaimi, Mohammad; Kendrick, Gary A

    2016-01-15

    The study of a Posidonia australis sedimentary archive has provided a record of changes in element concentrations (Al, Fe, Mn, Pb, Zn, Cr, Cd, Co, As, Cu, Ni and S) over the last 3000 years in the Australian marine environment. Human-derived contamination in Oyster Harbor (SW Australia) started ~100 years ago (AD ~1900) and exponentially increased until present. This appears to be related to European colonization of Australia and the subsequent impact of human activities, namely mining, coal and metal production, and extensive agriculture. Two contamination periods of different magnitude have been identified: Expansion period (EXP, AD ~1900-1970) and Establishment period (EST, AD ~1970 to present). Enrichments of chemical elements with respect to baseline concentrations (in samples older than ~115 cal years BP) were found for all elements studied in both periods, except for Ni, As and S. The highest enrichment factors were obtained for the EST period (ranging from 1.3-fold increase in Cu to 7.2-fold in Zn concentrations) compared to the EXP period (1.1-fold increase for Cu and Cr to 2.4-fold increase for Pb). Zinc, Pb, Mn and Co concentrations during both periods were 2- to 7-fold higher than baseline levels. This study demonstrates the value of Posidonia mats as long-term archives of element concentrations and trends in coastal ecosystems. We also provide preliminary evidence on the potential for Posidonia meadows to act as significant long-term biogeochemical sinks of chemical elements. PMID:26437357

  16. Theoretical studies of atomic properties and chemical stabilities in acid solutions of element Uus (Z=117) and Astatine

    NASA Astrophysics Data System (ADS)

    Chang, Z. W.; Li, J. G.; Dong, C. Z.

    2012-11-01

    Multi-configuration Dirac-Fock (MCDF) method was employed to calculate the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account. The Breit interaction and QED effects were also estimated. The uncertainties of calculated IPs, EAs and IR for Uus and At were reduced through an extrapolation procedure. The good consistency with available experimental and other theoretical values demonstrates the validity of the present results. These theoretical data were further used to predict the chemical stabilities of element Uus and At in acid solutions.

  17. Predicting from first principles the chemical evolution of crystalline compounds due to radioactive decay: The case of the transformation of CsCl to BaCl

    SciTech Connect

    Jiang, C.; Stanek, C. R.; Sickafus, K. E.; Uberuaga, B. P.; Marks, N. A.

    2009-04-01

    In this Brief Report, we use density functional theory to predict the existence of a heretofore unobserved crystalline compound, BaCl, and additionally predict it to be isostructural with NaCl (rocksalt). Due to the chemistry of Ba, which strongly prefers a 2+ charge state, compounds where Ba nominally exhibits a +1 charge (e.g., BaCl) are unlikely to be synthesized via conventional solid-state approaches. However, in considering the chemical evolution of {sup 137}Cs to {sup 137}Ba via {beta}{sup -} radioactive decay in a model nuclear waste form CsCl, we find that BaCl may be indeed relevant. The mechanical stability of this surprising structure is confirmed through examination of its elastic constants and phonon-dispersion relations. We have also analyzed the chemical bonding of rocksalt BaCl and found it to exhibit a complex mixture of ionic, metallic, and covalent characters. From our results, we demonstrate that the chemical evolution of crystalline structures due to radioactive decay may be a viable synthesis route for unforeseen materials with interesting properties.

  18. Distribution of chemical elements in calc-alkaline igneous rocks, soils, sediments and tailings deposits in northern central Chile

    NASA Astrophysics Data System (ADS)

    Oyarzún, Jorge; Oyarzun, Roberto; Lillo, Javier; Higueras, Pablo; Maturana, Hugo; Oyarzún, Ricardo

    2016-08-01

    This study follows the paths of 32 chemical elements in the arid to semi-arid realm of the western Andes, between 27° and 33° S, a region hosting important ore deposits and mining operations. The study encompasses igneous rocks, soils, river and stream sediments, and tailings deposits. The chemical elements have been grouped according to the Goldschmidt classification, and their concentrations in each compartment are confronted with their expected contents for different rock types based on geochemical affinities and the geologic and metallogenic setting. Also, the element behavior during rock weathering and fluvial transport is here interpreted in terms of the ionic potentials and solubility products. The results highlight the similarity between the chemical composition of the andesites and that of the average Continental Crust, except for the higher V and Mn contents of the former, and their depletion in Mg, Ni, and Cr. The geochemical behavior of the elements in the different compartments (rocks, soils, sediments and tailings) is highly consistent with the mobility expected from their ionic potentials, their sulfates and carbonates solubility products, and their affinities for Fe and Mn hydroxides. From an environmental perspective, the low solubility of Cu, Zn, and Pb due to climatic, chemical, and mineralogical factors reduces the pollution risks related to their high to extremely high contents in source materials (e.g., rocks, altered zones, tailings). Besides, the complex oxyanions of arsenic get bound by colloidal particles of Fe-hydroxides and oxyhydroxides (e.g., goethite), thus becoming incorporated to the fine sediment fraction in the stream sediments.

  19. Experimental investigations on the chemical state of solid fission-product elements in U3Si2

    NASA Astrophysics Data System (ADS)

    Ugajin, M.; Itoh, A.

    1994-10-01

    The uranium silicide U3Si2 has a congruent melting point of 1665 C and possesses higher uranium density (11.3 g U/cc) and higher thermal conductivity than the uranium dioxide currently used in light water reactors. U3Si2 is in use as a research reactor fuel (US Nuclear Regulatory Commission, NUREG-1313, July, 1988), representing a potentiality for power reactor fuel. A first attempt is made in this study to predict the chemical state of the solid fission-product elements comprising zirconium, molybdenum, rare earth elements, alkaline earth metals and elements of the platinum group. Ternary phase equilibria in the U-Mo-Si and U-Ru-Si systems are also investigated to supplement the fission product chemistry in U3Si2.

  20. Trace element identification of three chemically distinct very low titanium (VLT) basalt glasses from Apollo 17

    NASA Astrophysics Data System (ADS)

    Lindstrom, David J.; McKay, David S.; Wentworth, Susan J.; Martinez, Rene R.

    1994-02-01

    Small VLT samples from Apollo 17 soils were analyzed for trace elements using newly developed high sensitivity INAA techniques. Three distinct groups of VLT compositions are identified. Cobalt contents clearly delineate the HICo, MECo, and LOCo groups, which are also clearly identifiable by their major and minor element compositions. The results allow conclusions to be drawn concerning the sequence of events that produced the regolith at the Apollo 17 landing site.

  1. Chemical studies of differentiated meteorites. I - Labile trace elements in Antarctic and non-Antarctic eucrites

    NASA Technical Reports Server (NTRS)

    Paul, Rick L.; Lipschutz, Michael E.

    1990-01-01

    Element contents of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn were analyzed, using RNAA, in 25 Antarctic and nine non-Antarctic eucrites to determine whether these two populations differ significantly in thermal history and derive from the same or different eucrite parent body. Data for these 15 elements indicate that basaltic Antarctic and non-Antarctic eucrite populations reflect the same genetic processes and, hence, come from the same parent asteroid.

  2. Divergent variations in concentrations of chemical elements among shrub organs in a temperate desert

    NASA Astrophysics Data System (ADS)

    He, Mingzhu; Song, Xin; Tian, Fuping; Zhang, Ke; Zhang, Zhishan; Chen, Ning; Li, Xinrong

    2016-01-01

    Desert shrubs, a dominant component of desert ecosystems, need to maintain sufficient levels of nutrients in their different organs to ensure operation of various physiological functions for the purpose of survival and reproduction. In the present study, we analyzed 10 elements in leaves, stems, and roots of 24 dominant shrub species from 52 sites across a temperate desert ecosystem in northwestern China. We found that concentrations of all 10 elements were higher in leaves than in stems and roots, that non-legumes had higher levels of leaf Na and Mg than did legumes, and that Na was more concentrated in C4 leaves than in C3 leaves. Scaling relationships of elements between the photosynthetic organ (leaf) and non-photosynthetic organs (stem and root) were allometric. Results of principal components analysis (PCA) highlighted the important role of the elements responsible for osmoregulation (K and Na) in water utilization of desert shrubs. Soil properties and taxonomy explained most variation of element concentrations in desert shrubs. Desert shrubs may not be particularly susceptible to future change in climate factors, because most elements (including N, P, K, Ca, Mn, Zn, and Cu) associated with photosynthesis, osmoregulation, enzyme activity, and water use efficiency primarily depend on soil conditions.

  3. Divergent variations in concentrations of chemical elements among shrub organs in a temperate desert.

    PubMed

    He, Mingzhu; Song, Xin; Tian, Fuping; Zhang, Ke; Zhang, Zhishan; Chen, Ning; Li, Xinrong

    2016-01-01

    Desert shrubs, a dominant component of desert ecosystems, need to maintain sufficient levels of nutrients in their different organs to ensure operation of various physiological functions for the purpose of survival and reproduction. In the present study, we analyzed 10 elements in leaves, stems, and roots of 24 dominant shrub species from 52 sites across a temperate desert ecosystem in northwestern China. We found that concentrations of all 10 elements were higher in leaves than in stems and roots, that non-legumes had higher levels of leaf Na and Mg than did legumes, and that Na was more concentrated in C4 leaves than in C3 leaves. Scaling relationships of elements between the photosynthetic organ (leaf) and non-photosynthetic organs (stem and root) were allometric. Results of principal components analysis (PCA) highlighted the important role of the elements responsible for osmoregulation (K and Na) in water utilization of desert shrubs. Soil properties and taxonomy explained most variation of element concentrations in desert shrubs. Desert shrubs may not be particularly susceptible to future change in climate factors, because most elements (including N, P, K, Ca, Mn, Zn, and Cu) associated with photosynthesis, osmoregulation, enzyme activity, and water use efficiency primarily depend on soil conditions. PMID:26818575

  4. Divergent variations in concentrations of chemical elements among shrub organs in a temperate desert

    PubMed Central

    He, Mingzhu; Song, Xin; Tian, Fuping; Zhang, Ke; Zhang, Zhishan; Chen, Ning; Li, Xinrong

    2016-01-01

    Desert shrubs, a dominant component of desert ecosystems, need to maintain sufficient levels of nutrients in their different organs to ensure operation of various physiological functions for the purpose of survival and reproduction. In the present study, we analyzed 10 elements in leaves, stems, and roots of 24 dominant shrub species from 52 sites across a temperate desert ecosystem in northwestern China. We found that concentrations of all 10 elements were higher in leaves than in stems and roots, that non-legumes had higher levels of leaf Na and Mg than did legumes, and that Na was more concentrated in C4 leaves than in C3 leaves. Scaling relationships of elements between the photosynthetic organ (leaf) and non-photosynthetic organs (stem and root) were allometric. Results of principal components analysis (PCA) highlighted the important role of the elements responsible for osmoregulation (K and Na) in water utilization of desert shrubs. Soil properties and taxonomy explained most variation of element concentrations in desert shrubs. Desert shrubs may not be particularly susceptible to future change in climate factors, because most elements (including N, P, K, Ca, Mn, Zn, and Cu) associated with photosynthesis, osmoregulation, enzyme activity, and water use efficiency primarily depend on soil conditions. PMID:26818575

  5. Ecotoxicological characteristic of a soil polluted by radioactive elements and heavy metals before and after its bioremediation

    NASA Astrophysics Data System (ADS)

    Georgiev, P.; Groudev, S.; Spasova, I.; Nikolova, M.

    2012-04-01

    Cinnamon soils from southeastern Bulgaria are heavily polluted with radionuclides (uranium, radium) and toxic heavy metals (copper and lead) due to the winds transportation of fine particles from flotation dumps to the soil surface. As a result of this, the polluted soils are characterized by a slightly alkaline pH (7.82) and positive net neutralization potential (+136.8 kg CaCO3/t). A fresh sample of cinnamon soil was subjected to remediation under laboratory conditions in four lysimeters each containing 70 kg of soil. The preliminary study revealed that most of the pollutants were presented as carbonate, reducible and oxidisable mobility fractions, i.e. pollutants ions were specifically adsorbed by carbonate and ferric iron minerals or were capsulated in sulfides. The applied soil treatment was connected with leaching of the pollutants located mainly in the horizon A, their transportation through the soil profile as soluble forms, and their precipitation in the rich-in-clay subhorizon B3. The efficiency of leaching depended on the activity of the indigenous microflora and on the chemical processes connected with solubilization of pollutants and formation of stable complexes with some organic compounds, chloride and hydrocarbonate ions. These processes were considerably enhanced by adding hay to the horizon A and irrigating the soil with water solutions containing the above-mentioned ions and some nutrients. After 18 months of treatment, each of the soil profiles in the different lysimeters was divided into five sections reflecting the different soil layers. The soil in these sections was subjected to a detailed chemical analysis and the data obtained were compared with the relevant data obtained before the start of the experiment. The best leaching of pollutants from horizon A was measured in the variants where soil mulching was applied. For example, the best leaching of lead (54.5 %) was found in the variant combining this technique and irrigation with solutions

  6. Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

    SciTech Connect

    Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

    2011-06-20

    Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

  7. Standard reference exergies of chemical elements in the oceanic reference medium. I. Consideration of modern hydrochemical data on the concentrations of elements in the oceanic medium and the deviation of their reactivity from the neutral one

    NASA Astrophysics Data System (ADS)

    Pinaev, G. F.

    2006-09-01

    A system (set) of standard reference exergies of chemical elements, called the Ocean-2 system, is presented. It includes refined exergies of nine atmospheric elements and 79 elements dissolved in the oceanic water with S = 35‰, pH 7.905, a standard temperature of 298.15 K, and a standard pressure of 101.325 kPa. These exergies were calculated in a simplified chemical approximation with the use of a unique representative species for each element, selected by thermodynamic sifting. The suggestion has been made that the Ocean-2 system of standard reference exergies is close to the lithospheric system.

  8. 18 Sco: A solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging

    SciTech Connect

    Meléndez, Jorge; Monroe, TalaWanda R.; Tucci Maia, Marcelo; Freitas, Fabrício C.; Karakas, Amanda I.; Yong, David; Asplund, Martin; Bedell, Megan; Bean, Jacob; Bergemann, Maria; Do Nascimento, José-Dias Jr.; Castro, Matthieu; Bazot, Michael; Alves-Brito, Alan

    2014-08-10

    We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R ∼ 110,000), high signal-to-noise ratio (800-1,000) Very Large Telescope UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are T{sub eff} = 5823 ± 6 K and log g = 4.45 ± 0.02 dex, i.e., 18 Sco is 46 ± 6 K hotter than the Sun and log g is 0.01 ± 0.02 dex higher. Its metallicity is [Fe/H] = 0.054 ± 0.005 dex, and its microturbulence velocity is +0.02 ± 0.01 km s{sup –1} higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04 ± 0.02 M{sub ☉} and that it is ∼1.6 Gyr younger than the Sun. We use precise High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities to search for planets, but none are detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, thus showing higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (∼0.02 dex), we successfully reproduce the r-process pattern in the Solar System. This is independent evidence for the universality of the r process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general.

  9. Mapping chemical elements on the surface of orthodontic appliance by SEM-EDX

    PubMed Central

    Mikulewicz, Marcin; Wołowiec, Paulina; Michalak, Izabela; Chojnacka, Katarzyna; Czopor, Wojciech; Berniczei-Royko, Adam; Vegh, Andras; Gedrange, Thomas

    2014-01-01

    Background During orthodontic treatment, the various elements that constitute the fixed appliance undergo different processes. As a result of a change of the surface, elution/coverage of metals on the surface can be observed in the process of corrosion/passivation. Material/Methods Scanning electron microscopy with an energy-dispersive X-ray analytical system (SEM-EDX) was used to analyze the composition of stainless steel elements of orthodontic fixed appliances (before and after orthodontic treatment), to obtain the composition of the surface of the elements. The analyzed elements were: brackets (Victory Series APC PLUS 022, 3M Unitek, Monrovia, CA, USA); wires (0.017×0.025, 3M Unitek, Monrovia, CA, USA); and bands (37+, 3M Unitek, Monrovia, CA, USA). Results The results showed a decrease of chromium and iron contribution to the surface, with increase of oxygen content in used vs. new elements of the appliance. Conclusions Our results confirm the formation of oxides (passivation layer) on the surface of stainless steel as a result of the presence of the orthodontic appliance in patients’ oral cavities. PMID:24857929

  10. Chemical studies of H chondrites. I - Mobile trace elements and gas retention ages

    NASA Technical Reports Server (NTRS)

    Lingner, David W.; Huston, Ted J.; Hutson, Melinda; Lipschutz, Michael E.

    1987-01-01

    Trends for 16 trace elements (Ag, As, Au, Bi, Cd, Co, Cs, Ga, In, K, Rb, Sb, Se, Te, Tl, and Zn), chosen to span a broad geochemical and thermal response range, in 44 H4-6 chondrites, differ widely from those in L4-6 chondrites. In particular, H chondrites classified as heavily shocked petrologically do not necessarily exhibit Ar-40 loss and vice versa. The clear-cut causal relationship between siderophile and mobile element loss with increasing late shock seen in L chondrites is not generally evident in the H group. H chondrite parent material experienced an early high temperature genetic episode that mobilized a substantial proportion of these trace elements so that later thermal episodes resulted in more subtle, collateral fractionations. Mildly shocked L chondrites escaped this early high temperature event, indicating that the two most numerous meteorite groups differ fundamentally in genetic history.

  11. Study of wetting on chemically soften interfaces by using combined solution thermodynamics and DFT calculations: forecasting effective softening elements.

    PubMed

    Shu, Guo Gang; Xu, Qiang; Wu, Ping

    2015-04-15

    Despite recent progress in understanding the wetting principles on soft solids, the roles of chemical bonding in the formation of interfaces have been largely ignored, because most of these studies are conducted at room temperatures. Here we propose a universal wetting principle from solution thermodynamics to account for the softening of both the solid and liquid surfaces (stable or metastable). Density functional theory (DFT) calculations are applied to evaluate the stability and electron transportation across the interfaces. We find that wetting is dominated by the system entropy changes involving not only the stable liquid alloy phase but also the metastable liquid oxide phases. The state-of-art multicomponent solution thermodynamic models and databases are applied to describe the entropy changes and predict the wetting behaviors. Our results show that by chemically softening either the liquid or the solid phase, the wetting angle reduces. And an effective soften agent/additive (either in the form of chemical elements or molecules) will weaken the bonds within the liquid (or solid) phase and promote new bonds at the interfaces, thus increasing the interface entropy. Subsequently, as an example, Ti and Zr are proposed as effective softening elements to improve the wetting of aluminum liquid on B6Si(s). This approach provides a concept and tool to advance research in catalytic chemistry, nucleation (growth), elastowetting, and cell-substrate interactions. PMID:25844936

  12. The Trinity of Life: The Genome, the Proteome, and the Mineral Chemical Elements

    ERIC Educational Resources Information Center

    Williams, R. J. P.; J. J. R. Francis da Silva

    2004-01-01

    A brief outline of the known or presumed initial environment and its changes over time is given to observe the connection between the origin and evolution of the metallomes of cells to the environment and its changes. The connection to the environment leads from the abundance and environmental availability of the elements and therefore gives an…

  13. An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

    NASA Technical Reports Server (NTRS)

    Ross, H. Richard

    1993-01-01

    A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

  14. Periodic Table Target: A Game that Introduces the Biological Significance of Chemical Element Periodicity

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; McGinty, Ragan L.; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    Periodic Table Target, a game for middle school or high school students, familiarizes students with the form of the periodic table and the biological significance of different elements. The Periodic Table Target game board is constructed as a class project, and the game is played to reinforce the content. Students are assigned several elements…

  15. Spinel from Apollo 12 Olivine Mare Basalts: Chemical Systematics of Selected Major, Minor, and Trace Elements

    NASA Technical Reports Server (NTRS)

    Papike, J. J.; Karner, J. M.; Shearer, C. K.; Spilde, M. N.

    2002-01-01

    Spinels from Apollo 12 Olivine basalts have been studied by Electron and Ion microprobe techniques. The zoning trends of major, minor and trace elements provide new insights into the conditions under which planetary basalts form. Additional information is contained in the original extended abstract.

  16. I. Nuclear Production Reaction and Chemical Isolation Procedure for Americium-240 II. New Superheavy Element Isotopes: Plutonium-242(Calcium-48,5n)(285)114

    NASA Astrophysics Data System (ADS)

    Ellison, Paul Andrew

    2011-12-01

    Part I discusses the study of a new nuclear reaction and chemical separation procedure for the production of 240Am. Thin 242Pu, natTi, and natNi targets were coincidently activated with protons from the 88-Inch Cyclotron, producing 240Am, 48V, and 57Ni, respectively. The radioactive decay of these isotopes was monitored using high-purity Ge gamma ray detectors in the weeks following irradiation. The excitation function for the 242 Pu(p, 3n)240Am nuclear reaction was measured to be lower than theoretical predictions, but high enough to be the most viable nuclear reaction for the large-scale production of 240 Am. Details of the development of a chemical separation procedure for isolating 240Am from proton-irradiated 242Pu are discussed. The separation procedure, which includes two anion exchange columns and two extraction chromatography columns, was experimentally investi- gated using tracer-level 241Am, 239Pu, and model proton-induced fission products 95Zr, 95Nb, 125Sb, and 152Eu. The separation procedure was shown to have an Am/Pu separation factor of >2x10 7 and an Am yield of ˜70%. The separation procedure was found to purify the Am sample from >99.9% of Eu, Zr, Nb, and Sb. The procedure is well suited for the processing of ˜1 gram of proton-irradiated 242Pu to produce a neutron-induced fission target consisting of tens of nanograms of 240Am. Part II describes the use of the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron for the study of the 242Pu(48Ca,5n)285114 nuclear re- action. The new, neutron-deficient, superheavy element isotope 285114 was produced in 48Ca irradiations of 242Pu targets at a center-of-target beam energy of 256 MeV ( E* = 50 MeV). The alpha decay of 285114 was followed by the sequential alpha decay of four daughter nuclides, 281Cn, 277Ds, 273Hs, and 269 Sg. 265Rf was observed to decay by spontaneous fission. The measured alpha-decay Q-values were compared with those from a macroscopic

  17. Detailed mass size distributions of elements and species, and aerosol chemical mass closure during fall 1999 at Gent, Belgium

    NASA Astrophysics Data System (ADS)

    Maenhaut, Willy; Cafmeyer, Jan; Dubtsov, Sergei; Chi, Xuguang

    2002-04-01

    A 10-stage microorifice uniform deposit impactor (MOUDI) and a 12-stage small deposit area low pressure impactor (SDI) were operated at Gent from 6 September to 30 October 1999. Thirty-four parallel samples (of typically 24 h) were collected. The MOUDI samples were analysed for the particulate mass (PM) by weighing, and for organic carbon (OC) and elemental carbon (EC) by a thermal-optical transmission technique. The SDI samples were analysed for 27 elements by PIXE. PM and OC exhibited typically a rather similar bimodal size distribution, with most of their mass in the submicrometer size range. EC was predominantly associated with fine particles, with maximum typically at around 0.2 μm equivalent aerodynamic diameter (EAD). Sulphur was also mainly in the fine size range, but with maximum at 0.5 μm EAD. Other elements with mainly a fine mode were V, Ni, As, Se and Pb. The crustal elements (Al, Si, Ti, Fe, Zr) exhibited mostly a unimodal coarse mode size distribution, with maximum at about 4 μm EAD. Other elements with mainly a coarse mode were Na, Mg, P, Ca, Cr, Mn, Cu, Ga and Sr. The elements K, Zn and Rb were generally bimodal. Aerosol chemical mass closure calculations indicated that organic aerosol and crustal matter were the major aerosol types in the supermicrometer size range, and that the dominant aerosol types in the submicrometer fraction were organic aerosol and sulphate. On average, 74% of the gravimetric PM was accounted for by the aerosol types considered.

  18. Role of alkyl alcohol on viscosity of silica-based chemical gels for decontamination of highly radioactive nuclear facilities

    SciTech Connect

    Choi, B. S.; Yoon, S. B.; Jung, C. H.; Lee, K. W.; Moon, J. K.

    2012-07-01

    Silica-based chemical gel for the decontamination of nuclear facilities was prepared by using fumed silica as a viscosifier, a 0.5 M Ce (IV) solution dissolved in concentrated nitric acid as a chemical decontamination agent, and tripropylene glycol butyl ether (TPGBE) as a co-viscosifier. A new effective strategy for the preparation of the chemical gel was investigated by introducing the alkyl alcohols as organic solvents to effectively dissolve the co-viscosifier. The mixture solution of the co-viscosifier and alkyl alcohols was more effective in the control of viscosity than that of the co-viscosifier only in gel. Here, the alkyl alcohols played a key role as an effective dissolution solvent for the co-viscosifier in the preparation of the chemical gel, resulting in a reducing of the amount of the co-viscosifier and gel time compared with that of the chemical gel prepared without the alkyl alcohols. It was considered that the alkyl alcohols contributed to the effective dissolution of the co-viscosifier as well as the homogeneous mixing in the formation of the gel, while the co-viscosifier in an aqueous media of the chemical decontamination agent solution showed a lower solubility. The decontamination efficiency of the chemical gels prepared in this work using a multi-channel analyzer (MCA) showed a high decontamination efficiency of over ca. 94% and ca. 92% for Co-60 and Cs-137 contaminated on surface of the stainless steel 304, respectively. (authors)

  19. The influence of natural factors on the concentrations of chemical elements in urban soils

    NASA Astrophysics Data System (ADS)

    Alekseenko, Alexey; Alekseenko, Vladimir

    2013-04-01

    The statistically treated results of more than 10 000 soil samples analyses for 25 elements were used during the work preparing. For estimating the total influence of natural factors on the global level we could consider the average concentrations in urban soils (the Clarke numbers of urban soils) with the average concentrations in the Earth crust and Earth soils. The analysis showed the heredity of general properties of elements concentrations from the Earth crust. However the higher concentrations of As, Cd, Cs, Mo, N, S, Ti and V in the soils of cities are explained by the combined effects of processes of soil formation and human impact, and Zn, Pb, Ba, Sr, Ca, Hg, B - by the prevailing human impact. On the regional level the natural factors influence was estimated by the comparing of soils of cities with the equal technogenic impact and number of population, but located in different geographical and climate zones. The common conformities with law were not found out, but the mentioned factors had an effect on the elements concentrations. The valuation of natural factors influence in the soils of one city was carried out by comparison the urban landscapes soils, which differ only in one characteristic. Geomorphologic peculiarities had the doubtless influence on the background concentrations of Pb, Sr, Ag, Zn, Yb, Co, Sn, Cr. etc., but in every case the connection of maximum and minimum background concentrations of the specific elements with the certain geomorphologic structures depended on number of building storeys, location of industrial zones, parks, etc. The certain associations of plants were also affected the background elements concentrations in soils of several cities. The increased concentrations of elements were more often detected - other things being equal - in the landscapes with mixed decorative fruit and berry plant association (?u, Pb, Co, Mn, Ti, Sr), less often - with agricultural fruit and berry plant association (Zn, Ag, Sn, Ba, Cr). In parks

  20. Chemical composition and some trace element contents in coals and coal ash from Tamnava-Zapadno Polje Coal Field, Serbia

    SciTech Connect

    Vukasinovic-Pesic, V.; Rajakovic, L.J.

    2009-07-01

    The chemical compositions and trace element contents (Zn, Cu, Co, Cr, Ni, Pb, Cd, As, B, Hg, Sr, Se, Be, Ba, Mn, Th, V, U) in coal and coal ash samples from Tamnava-Zapadno Polje coal field in Serbia were studied. The coal from this field belongs to lignite. This high volatility coal has high moisture and low S contents, moderate ash yield, and high calorific value. The coal ash is abundant in alumosilicates. Many trace elements such as Ni > Cd > Cr > B > As > Cu > Co > Pb > V > Zn > Mn in the coal and Ni > Cr > As > B > Cu > Co = Pb > V > Zn > Mn in the coal ash are enriched in comparison with Clarke concentrations.

  1. Radioactive heat sources in the lunar interior.

    NASA Technical Reports Server (NTRS)

    Hays, J. F.

    1972-01-01

    Published models for the moon's thermal history typically imply present day central temperatures far too high to be consistent with the recently proposed lunar temperature profile of Sonett et al. (1971). Furthermore, chemical data on Apollo samples show that the moon is depleted relative to chondrites in volatile elements, and possibly enriched relative to chondrites in refractory elements. Additional thermal models have therefore been investigated in order to set upper limits on lunar radioactivity consistent with the proposed temperature distribution. For an initially cold, uniform moon, devoid of potassium, a maximum uranium content of 23 parts per billion is inferred.

  2. Chemical evolution of r-process elements in the Draco dwarf spheroidal galaxy

    NASA Astrophysics Data System (ADS)

    Ishigaki, M. N.; Tsujimoto, T.; Shigeyama, T.; Aoki, W.

    2016-08-01

    A dominant astrophysical site for r-process, which is responsible for producing heavy neutron-capture elements, is unknown. Dwarf spheroidal galaxies around the Milky Way halo provide ideal laboratories to investigate the origin and evolution of r-process elements. We carried out high-resolution spectroscopic observations of three giant stars in the Draco dwarf spheroidal galaxy to estimate their europium abundances. We found that the upper-limits of [Eu/H] are very low in the range [Fe/H] < -2, while this ratio is nearly constant at higher metallicities. This trend is not well reproduced with models which assume that Eu is produced together with Fe by SNe, and may suggest the contribution from other objects such as neutron-star mergers.

  3. Major and EDXRF Trace Element Chemical Analyses of Volcanic Rocks from Lassen Volcanic National Park and Vicinity, California

    USGS Publications Warehouse

    Clynne, Michael A.; Muffler, L.J.P.; Siems, D.F.; Taggart, J.E., Jr.; Bruggman, Peggy

    2008-01-01

    This open-file report presents WDXRF major-element chemical data for late Pliocene to Holocene volcanic rocks collected from Lassen Volcanic National Park and vicinity, California. Data for Rb, Sr, Ba, Y, Zr, Nb, Ni, Cr, Zn and Cu obtained by EDXRF are included for many samples. Data are presented in an EXCEL spreadsheet and are keyed to rock units as displayed on the Geologic Map of Lassen Volcanic National Park and vicinity (Clynne and Muffler, in press). Location of the samples is given in latitude and longitude in degrees and decimal minutes and in decimal degrees.

  4. Numerical values of the surface free energies of solid chemical elements

    NASA Astrophysics Data System (ADS)

    Mezey, L. Z.; Giber, J.

    1984-10-01

    The applicability of a 'standard table' of values of surface free energies (or enthalpies) obtained by the CCSS (complex calculation of surface segregation) method is demonstrated by comparing calculated surface-free-energy values with several recently published experimental results. The investigation (encompassing temperatures from 1023 to 2075 K) shows that a simplified variation of the second step of CCSS is applicable in the calculation of the surface free energies of polycrystalline solid elements for any temperature of interest.

  5. Chemical properties of rare earth elements in typical medical waste incinerator ashes in China.

    PubMed

    Zhao, Lijuan; Zhang, Fu-Shen; Zhang, Jingxin

    2008-10-30

    Medical waste (MW) ashes from different types of MW incinerators were examined to detect the characteristics and environmental impact of rare earth elements (REEs). The results showed that total REE contents in the ash samples ranged from 10.2 to 78.9 mg/kg. REEs in bottom ash were apparently higher than those in fly ash. Average REE contents in the ashes followed the sequence of Ce>La>Nd>Y>Gd>Pr>Sm>Dy>Er>Yb>Ho>Eu>Tb>Lu>Tm. Some of the elements, such as Sm, Dy, Ho, Er, Yb in the ash samples were in normal or nearly normal distribution, but Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Tm, Lu were not normally distributed, indicating some of the ash samples were enriched with these elements. Crust-normalized REE patterns indicated that two types of the MW ashes were obviously enriched with Gd and La. Sequential extraction results showed that REEs in the ash mainly presented as residual fraction, while exchangeable and carbonate fractions were relatively low. DTPA- and EDTA-extraction tests indicated that REEs in the MW ashes were generally in low bioavailability. PMID:18329796

  6. Chemical studies of selected trace elements in hot-spring drainages of Yellowstone National Park

    SciTech Connect

    Stauffer, R.E.; Jenne, E.A.; Ball, J.W.

    1980-01-01

    Intensive chemical studies were made of S(-II), O/sub 2/, Al, Fe, Mn, P, As(III), As(V), and Li in waters from two high-Cl, low Ca-Mg hotspring drainages in the Lower Geyser Basin, a warm spring system rich in Ca and Mg in the Yellowstone Canyon area, and the Madison River system above Hebgen Lake. Analyses were also made of other representative thermal waters from the Park.

  7. Near-field chemical composition of porewaters in a near-surface low-level radioactive waste vault

    SciTech Connect

    Caron, F.; Haas, M.K.; Torok, J.; Manni, G.

    1997-12-31

    A long-term waste degradation experiment has been performed with actual low-level radioactive wastes (LLRW) at the Chalk River Laboratories (CRL), to support the licensing and modelling efforts for near-surface disposal. The wastes consist of paper, mop heads, paper towels, used clothing, etc. The wastes were compacted into bales and sealed into separate steel containers, which were connected to leachate collection systems for sampling. The leachates collected had a composition typical of landfill leachates. The major inorganic ions were Na, Ca, Cl, and Fe, and the ionic strength was {approximately}0.05 M. The relative distribution of inorganic ions in the leachates was remarkably similar between bales. Volatile fatty acids (VFA) were the major species of dissolved organic carbon (DOC; total DOC up to 7,000 mg/L). A typical composition of leachates is proposed, which can be used in geochemical and source term modelling.

  8. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ≳ +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  9. Chemical and sewage sludge co-incineration in a full-scale MSW incinerator: toxic trace element mass balance.

    PubMed

    Biganzoli, Laura; Grosso, Mario; Giugliano, Michele; Campolunghi, Manuel

    2012-10-01

    Co-incineration of sludges with MSW is a quite common practice in Europe. This paper illustrates a case of co-incineration of both sewage sludges and chemical sludges, the latter obtained from drinking water production, in a waste-to-energy (WTE) plant located in northern Italy and equipped with a grate furnace, and compares the toxic trace elements mass balance with and without the co-incineration of sludges. The results show that co-incineration of sewage and chemical sludges does not result in an increase of toxic trace elements the total release in environment, with the exception of arsenic, whose total release increases from 1 mg t(fuel) (-1) during standard operation to 3 mg t(fuel) (-1) when sludges are co-incinerated. The increase of arsenic release is, however, attributable to the sole bottom ashes, where its concentration is five times higher during sludge co-incineration. No variation is observed for arsenic release at the stack. This fact is a further guarantee that the co-incineration of sludges, when performed in a state-of-the-art WTE plant, does not have negative effects on the atmospheric environment. PMID:22584266

  10. Levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain.

    PubMed

    Lage, J; Almeida, S M; Reis, M A; Chaves, P C; Ribeiro, T; Garcia, S; Faria, J P; Fernández, B G; Wolterbeek, H T

    2014-01-01

    The adverse health effects of airborne particles have been subjected to intense investigation in recent years; however, more studies on the chemical characterization of particles from pollution emissions are needed to (1) identify emission sources, (2) better understand the relative toxicity of particles, and (3) pinpoint more targeted emission control strategies and regulations. The main objective of this study was to assess the levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain. Instrumental and biomonitoring techniques were integrated and analytical methods for k0 instrumental neutron activation analysis and particle-induced x-ray emission were used to determine element content in aerosol filters and lichens. Results indicated that in general local industry contributed to the emissions of As, Sb, Cu, V, and Ni, which are associated with combustion processes. In addition, the steelwork emitted significant quantities of Fe and Mn and the cement factory was associated with Ca emissions. The spatial distribution of Zn and Al also indicated an important contribution of two industries located outside the studied area. PMID:25072718