WorldWideScience

Sample records for classes of chemical elements

  1. A class of chemical pinning centers including two elements foreign to HTS

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Sawh, Ravi-Persad

    2003-01-01

    Very small deposits are formed when two foreign elements, A and B, are added to textured (RE)BCO. These deposits increase the J{sub c} of samples and hence the maximum trapped field. Deposit sizes are generally in the range 200-400 nm. Their chemical composition is (A{sub x},B{sub y})(RE)Ba{sub 2}O{sub 6}, where x+y=1 and x=y{+-}0.1. Their structure is double perovskite. The deposits produce two types of pinning, one by refinement (e.g., of the Y211 phase) and the other due to the double perovskite deposits themselves. In those cases tested, the refinement increases J{sub c} by factors exceeding 1.33, and the deposits increase J{sub c} by factors exceeding 2, for a total increase by a factor exceeding 2.66. Element A can be U, W or Mo. Element B can be Pt or Zr. We speculate on possible additional elements in classes A and B.

  2. Chemical characterization of element 112.

    Science.gov (United States)

    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

  3. Chemical characterization of element 112

    Science.gov (United States)

    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.

  4. Chemical characterization of bohrium (element 107)

    Science.gov (United States)

    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

  5. Chemical characterization of bohrium (element 107)

    Science.gov (United States)

    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.

  6. Chemical properties of element 106 (seaborgium)

    International Nuclear Information System (INIS)

    The synthesis, via nuclear fusion reactions, of elements heavier than the actinides, allows one to prove the limits of the periodic table as a means of classifying the elements. In particular, deviations in the periodicity of chemical properties for the heaviest elements are predicted as a consequence of increasingly strong relativistic effects on the electronic shell structure. The transactinide elements have now been extended up to element 112, but the chemical properties have been investigated only for the first two of the transactinide elements, 104 and 105. Those studies showed that relativistic effect render these two elements chemically different from their lighter homologues in the same columns of the periodic table. Here we report the chemical separation of element 106 (seaborgium, Sg) and investigations of its chemical behaviour in the gas phase and in aqueous solution. The methods that we use are able to probe the reactivity of individual atoms, and are based on the detection of just seven atoms of seaborgium we find that it exhibits properties characteristic of the group 6 homologues molybdenum and tungsten. Thus seaborgium appears to restore the trends of the periodic table disrupted by relativistic effects in elements 104 and 105. (Author)

  7. The origin of the chemical elements

    International Nuclear Information System (INIS)

    The subject is discussed in relation to the composition of initially created matter and changes which have occurred during the life history of the universe, with particular reference to our galaxy and nearby galaxies. Headings are: observations of element abundances (stars, gas clouds in our own and nearby galaxies, hot gas in galaxy clusters, the solar system); the originally created matter (Big Bang theory and early nuclear reactions); processes changing observed composition (galactic evolution; nuclear fusion reactions in stellar interiors; chemical composition of a highly evolved massive star); supernovae (production of heavy elements); chemical evolution of the galaxy; production of very heavy elements (s process, r process). (U.K.)

  8. Predicion of Chemical Element Contents in Soils

    Institute of Scientific and Technical Information of China (English)

    KESHAN-ZHE; QIANJUN-LONG; 等

    1994-01-01

    Assuming that the regularity for the dynamic changes of the chrono-sequences of chemical element contents in tree rings follows a k-order constant coefficient differential equation and substituting the differential with the difference,we could obtain the inferred value ym+k+1 by the formula:ym+k+1=c1ym+1+c2Ym+2+…ckym+kEach coefficient ci in the formula may be ascertained by use of the measured data in the chrono-sequences,Extending the chrono-sequences on the assumption that the regularity of dynamic changes wouldn't change in the near future,the contents of chemical elements in the soils may be predicted in terms of a logarithmic linear correlation model.Also,this extension method could be used for the reproduction of the contents of chemical elemets in soils during different periods of time in the past.

  9. Distribution of chemical elements in marine algae

    International Nuclear Information System (INIS)

    The analytical data on the distribution of chemical elements in the biosphere is promptly increasing in numbers. A method of data analysis which can arrange these data in accordance with a definite principle has been proposed. In our laboratory, systematic study of chemical elements in various Japanese seaweeds has been carried out and a relationship between the concentration factor for elements on a seaweed and its oceanic residence time emerged from the results: the logarithm of the concentration factor(y) tends to be inversely proportional to the logarithm of the residence time(x). Consequently the following rormula can be assumed: log y = log a + b log x. The values of log a, b, and the correlation coefficient r are calculated from the individual data. Usually the value of +r+ was more than 0.8. And in general the larger value of log a the sample has, the larger one of +b+ it has. This regularity between residence time and concentration factor was observed also in other phyla of marine organisms such as marine zoo plankton. Furthermore, since the ocean is closely connected with each of geochemical spheres, there is a tendency that the value of oceanic residence time has similar relation with the concentration ratio of many other geochemical abundance to oceanic chemical abundance as well as with concentration factor of marine organisms. In connection with these results it was found that there is close correlation between the two of each ratio of geochemical abundance to oceanic abundance. On the other hand, it was seen that there are no close correlation between ratios of geochemical abundance to crustal chemical abundance or other ones. Therefore it is again presumed that the ocean gives important contributions on the distribution of chemical elements in many kinds of substances in biosphere. (author)

  10. Finite Groups with Three Conjugacy Class Sizes of some Elements

    Indian Academy of Sciences (India)

    Qingjun Kong

    2012-08-01

    Let be a finite group. We prove as follows: Let be a -solvable group for a fixed prime . If the conjugacy class sizes of all elements of primary and biprimary orders of are $\\{1,p^a,n\\}$ with and two positive integers and (,)=1, then is -nilpotent or has abelian Sylow -subgroups.

  11. Global asymptotic stability for a class of nonlinear chemical equations

    OpenAIRE

    Anderson, David F.

    2007-01-01

    We consider a class of nonlinear differential equations that arises in the study of chemical reaction systems that are known to be locally asymptotically stable and prove that they are in fact globally asymptotically stable. More specifically, we will consider chemical reaction systems that are weakly reversible, have a deficiency of zero, and are equipped with mass action kinetics. We show that if for each $c \\in \\R_{> 0}^m$ the intersection of the stoichiometric compatibility class $c + S$ ...

  12. Atlantic Forest. A natural reservoir of chemical elements

    International Nuclear Information System (INIS)

    The accumulation of chemical elements in biological compartments is one of the strategies of tropical species to adapt to a low-nutrient soil. This study focuses on the Atlantic Forest because of its eco-environmental importance as a natural reservoir of chemical elements. About 20 elements were determined by INAA in leaf, soil, litter and epiphyte compartments. There was no seasonality for chemical element concentrations in leaves, which probably indicated the maintenance of chemical elements in this compartment. Considering the estimated quantities, past deforestation events could have released large amounts of chemical elements to the environment. (author)

  13. Chemical identification and properties of element 112

    CERN Document Server

    Yakushev, A B; Zvára, I

    2002-01-01

    The second experiment on the chemical identification of element 112 performed at the FLNR (Dubna) is reported. Similar to the first test in 2000, the 2 mg/cm sup 2 sup n sup a sup t U target was bombarded with the 262-MeV sup 4 sup 8 Ca ions aiming at the production of sup 2 sup 8 sup 3 112, which as reported earlier decays by SF with a half-life of 3 min. The bombardment products recoiling from the target were thermalized in flowing helium and transported by the gas to detectors 25 m apart. Of all the heavy elements, the reaction products, only Hg, Rn and At were efficiently transported and thus selectively isolated. This time the beam dose was much higher (2.8 centre dot 10 sup 1 sup 8) and two different devices for detecting fission fragments and alpha particles were employed. The device used earlier was an assembly of sixteen PIPS detectors coated with Au to detect 'Hg-like' nuclides being adsorbed on Au at ambient temperature. The new one was a flow-through ionization chamber, 5000 cm sup 3 in volume, wh...

  14. Turbulent mixing of chemical elements in galaxies

    Science.gov (United States)

    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

  15. THE EFFECT OF DRAINAGE ON CHEMICAL ELEMENTS CONTENT OF MARSH

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper takes marsh in the Sanjiang Plain as an example in order to research the effect of draining on the chemical elements in marsh. The Sanjiang Ecological Test Station of Mire and Uetland serves as the resarch base. The authors selected soil samples in the Sanjiang Plain (the top and the end of the drain, marsh soil and degeneration marsh soil), mainly analyzed contents of main ions (HCO3-, Cl-, SO42-and NO3-), main heavy metals (Fe, Mn, Znand Cu), nutritive elements (N, P,K), organic matter and pH value. By testing these samples as above, the paper initially researches the effect on chemical elements content by draining by the means of the contrast of chemical elements contents between marsh soil and degenerative marsh soil and different characteristics of marsh soil elements. Results show that a lot of chemical elements had been lost because of draining.

  16. Recent achievements in chemical studies of heaviest elements

    Science.gov (United States)

    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.

  17. Recent achievements in chemical studies of heaviest elements

    International Nuclear Information System (INIS)

    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.

  18. An Alternate Graphical Representation of Periodic table of Chemical Elements

    OpenAIRE

    Abubakr, Mohd

    2009-01-01

    Periodic table of chemical elements symbolizes an elegant graphical representation of symmetry at atomic level and provides an overview on arrangement of electrons. It started merely as tabular representation of chemical elements, later got strengthened with quantum mechanical description of atomic structure and recent studies have revealed that periodic table can be formulated using SO(4,2)* SU(2) group. IUPAC, the governing body in Chemistry, doesn't approve any periodic table as a standard...

  19. Transfer of chemical elements to breast milk

    International Nuclear Information System (INIS)

    The project is intended to yield information on the transfer factors describing the transfer of ingested radionuclides to breast milk for the following elements: antimony, cerium, chromium, cobalt, gallium, lanthanum, molybdenum, niobium, radium, ruthenium, silver, thorium, titanium, and uranium. Those yet unknown or poorly known transfer factors are required in order to be able to develop a reliable model for description and assessment of the transfer of the radionuclides and the possibly resulting hazardous doses to infants, and for subsequent formulation of recommendations for radiological protection of the population. (orig./CB)

  20. Chemical identification and properties of element 112

    Czech Academy of Sciences Publication Activity Database

    Yakushev, AB.; Zvára, Ivo; Oganessian, YT.; Belozerov, AV.; Dmitriev, S. N.; Eichler, B.; Hubener, S.; Sokol, EA.; Turler, A.; Yeremin, AV.; Buklanov, GV.; Chelnokov, ML.; Chepigin, VI.; Gorshkov, VA.; Gulyaev, AV.; Lebedev, VY.; Malyshev, ON.; Popeko, AG.; Soverna, S.; Szeglowski, Z.; Timokhin, SN.; Tretyakova, SP.; Vasko, VM.; Itkis, MG.

    2003-01-01

    Roč. 91, č. 8 (2003), s. 433-439. ISSN 0033-8230 Institutional research plan: CEZ:AV0Z1048901 Keywords : element 112 * superheavy elements * transactinoids Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 0.940, year: 2003

  1. Measurements of radon and chemical elements: Popocatepetl volcano

    International Nuclear Information System (INIS)

    The Popocatepetl volcano is a higher risk volcano located at 60 Km from Mexico City. Radon measurements on soil in two fixed seasons located in the north slope of volcano were carried out. Moreover the radon content, major chemical elements and tracks in water samples of three springs was studied. The radon of soil was determined with solid detectors of nuclear tracks (DSTN). The radon in subterranean water was evaluated through the liquid scintillation method and it was corroborated with an Alpha Guard equipment. The major chemical elements were determined with conventional chemical methods and the track elements were measured using an Icp-Ms equipment. The radon on soil levels were lower, indicating a moderate diffusion of the gas across the slope of the volcano. The radon in subterranean water shown few changes in relation with the active scene of the volcano. The major chemical elements and tracks showed a stable behavior during the sampling period. (Author)

  2. Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds

    OpenAIRE

    Labushev, Mikhail M.

    2013-01-01

    The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. B...

  3. Reconstructing the cosmic evolution of the chemical elements

    CERN Document Server

    Frebel, Anna

    2014-01-01

    The chemical elements are created in nuclear fusion processes in the hot and dense cores of stars. The energy generated through nucleosynthesis allows stars to shine for billions of years. When these stars explode as massive supernovae, the newly made elements are expelled, chemically enriching the surrounding regions. Subsequent generations of stars are formed from gas that is slightly more element enriched than that from which previous stars formed. This chemical evolution can be traced back to its beginning soon after the Big Bang by studying the oldest and most metal-poor stars still observable in the Milky Way today. Through chemical analysis, they provide the only available tool for gaining information about the nature of the short-lived first stars and their supernova explosions more than thirteen billion years ago. These events set in motion the transformation of the pristine universe into a rich cosmos of chemically diverse planets, stars, and galaxies.

  4. Chemical elements dynamic in the fermentation process of ethanol producing

    International Nuclear Information System (INIS)

    This paper provides useful information about the dynamics of chemical elements analysed by instrumental neutron activation analysis (INAA) and, found in the various segments of the fermentation process of producing ethanol from sugar cane. For this, a mass balance of Ce, Co, Cs, Eu, Fe, Hf, La, Sc, Sm, and Th, terrigenous elements, as well as Br, K, Rb, and Zn, sugar cane plant elements, has been demonstrated for the fermentation vats in industrial conditions of ethanol production. (author). 10 refs, 4 figs, 1 tab

  5. The periodic system of chemical elements: old and new developments

    International Nuclear Information System (INIS)

    Some historical facts about the construction of a periodic system of chemical elements are reviewed. The Madelung rule is used to generate an unusual format for the periodic table. Following the work of Byakov, Kulakov, Rumer and Fet, such a format is further refined on the basis of a chain of groups starting with SU(2)xS0(4.2)

  6. Chemical behaviour of transuranic elements in the natural environment

    International Nuclear Information System (INIS)

    The chemical behaviour of transuranic 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, mineralisation etc. This paper reviews the present state of knowledge on some of these particular reactions. The emphasis is placed on how the individual reactions can be appraised for the long-term prediction of the geochemical behaviour of transuranic elements in the natural environment. Of the various reactions, the primary thermodynamic processes of dissolution of transuranic compounds in aquatic solution, complexation with important anions present in groundwater and colloid generation are discussed with notable examples. Various laser spectroscopy in use for the chemical speciation are mentioned briefly as for their spectroscopic capability as well as applicability. The present review discussion is primarily directed to a better understanding of the migration behaviour of transuranic elements in natural aquifer systems. (author) 100 refs

  7. Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds

    CERN Document Server

    Labushev, Mikhail M

    2013-01-01

    The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. Beta-packet of oxides and hydroxides minerals includes 88 known minerals and five chemical compounds - N2O5, CO2, CO, SO3 and SO2. Two minerals of the packet have not been determined yet. Besides, beta-packet of minerals with sulfur, selenium or arsenic is composed, with one mineral not defined yet. The results of the calculations can be used for further development of the Periodic Table of Chemical Elements and Chemical Compounds and their properties investigation.

  8. Nuclear and chemical properties of the transactinide elements

    International Nuclear Information System (INIS)

    Transactinide elements, whose atomic number larger than 104 and classified as 6d-transition elements in the periodic table, have seldom been studied of the chemical nature in spite of much interest in the possible relativistic effects of these superheavy nuclides. This report briefly reviews recent topics in the advancement for the superheavy (Z > 104) nuclide synthesis by means of cold fusion with varying combinations of incident and target atoms using ion accelerators, for example, at GSI, Darmstadt, and at JINR, Dubna. It also reviews recent progress in their nuclear and chemical properties studied by a world-wide cooperative research group working at GSI, Mainz University, Bern University, PSI, Uppsala University, Dubna and LBL groups into which JAERI group has joined since 1998. Moreover, expectation is stated for the successful synthesis of superheavy elements on employment of radioactive beams consisting of neutron-excess nuclides. (Ohno, S.)

  9. An Alternate Graphical Representation of Periodic table of Chemical Elements

    CERN Document Server

    Abubakr, Mohd

    2009-01-01

    Periodic table of chemical elements symbolizes an elegant graphical representation of symmetry at atomic level and provides an overview on arrangement of electrons. It started merely as tabular representation of chemical elements, later got strengthened with quantum mechanical description of atomic structure and recent studies have revealed that periodic table can be formulated using SO(4,2)* SU(2) group. IUPAC, the governing body in Chemistry, doesn't approve any periodic table as a standard periodic table. The only specific recommendation provided by IUPAC is that the periodic table should follow the 1 to 18 group numbering. In this technical paper, we describe a new graphical representation of periodic table, referred as 'Circular form of Periodic table'. The advantages of circular form of periodic table over other representations are discussed along with a brief discussion on history of periodic tables.

  10. Synthesis of the heaviest chemical elements - results and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, G.

    1988-11-01

    All 17 artificially produced elements heavier than uranium were discovered by nuclear-chemical synthesis. The three heaviest ones - elements 107, 108 and 109 - were snythesized at the heavy-ion accelerator UNILAC in Darmstadt by nuclear fusion from the heaviest stable nuclei, lead-208 and bismuth-209, and the most neutron-rich stable isotopes of chromium and iron: element 107 from bismuth-209 (atomic number Z=83) and chromium-54 (Z=24), element 108 from lead-208 (Z=82) and iron-58 (Z=26), and element 109 from bismuth-209 and iron-58. The first isotopes detected were those with mass numbers 262 (Z=107), 265 (Z=108) and 266 (Z=109); these nuclei are short-lived ed -emitters with half-lives of 8.2 ms, 1.8 ms and 3.4 ms, respectively. The yields of these reactions are extremely small; only three atoms of element 109 have ever been observed. Experiments to synthesize element 110 have given ambiguous results. All attempts to detect the 'superheavy' elements with proton numbers near Z=114 and neutron numbers near N=184 have thus far failed. These elements have been predicted theoretically, and many attempts to synthesize them have been made, e.g. at UNILAC by fusion of calcium-48 (Z=20) with curium-248 (Z=96), or by transference of protons in the collision of two very heavy nuclei such as uranium-238 (Z=92). Surprisingly, the heaviest known nuclei are far more stable toward spontaneous fission into two fragments than was expected, but their synthesis is strongly hindered - much more than was initially anticipated. It is this hindrance rather than the decreasing nuclear stability which seems to presently limit the extent of the periodic table: even heavier elements should be able to exist, but no way has yet been found to produce them.

  11. Some Chemical Group Separations of Radioactive Trace Elements

    International Nuclear Information System (INIS)

    As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials

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

    International Nuclear Information System (INIS)

    The chemical and nuclear properties of Lr and Ha have been studied, using 3-minute 260Lr and 35-second 262Ha. The crystal ionic radius of Lr3+ 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, Am3+ through Es3+, obtained by x-ray diffraction methods, and to Md3+ and Fm3+ which were determined in the same manner as Lr3+. The hydration enthalpy of -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 Lr3+ and Md3+ is anomalously small, as the ionic radius of Lr3+ 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

  13. The origin of the chemical elements in cluster cores

    CERN Document Server

    de Plaa, J

    2012-01-01

    Metals play a fundamental role in ICM cooling processes in cluster cores through the emission of spectral lines. But when and how were these metals formed and distributed through the ICM? The X-ray band has the unique property of containing emission lines from all elements from carbon to zinc within the 0.1-10 keV band. Using XMM-Newton, the abundances of about 11 elements are studied, which contain valuable information about their origin. Most elements were formed in type Ia and core-collapse supernovae, which have very different chemical yields. Massive stars and AGB stars also contribute by providing most of the carbon and nitrogen in the ICM. Because feedback processes suppress star formation in the cluster centre, the element abundances allow us to directly probe the star formation history of the majority of stars that are thought to have formed between z=2-3. The spatial distribution in the core and the evolution with redshift also provide information about how these elements are transported from the me...

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

    Science.gov (United States)

    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.

  15. AN ANISOTROPIC NONCONFORMING FINITE ELEMENT METHOD FOR APPROXIMATING A CLASS OF NONLINEAR SOBOLEV EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Dongyang Shi; Haihong Wang; Yuepeng Du

    2009-01-01

    An anisotropic nonconforming finite element method is presented for a class of nonlinear Sobolev equations. The optimal error estimates and supercloseness are obtained for both semi-discrete and fully-discrete approximate schemes, which are the same as the traditional finite element methods. In addition, the global superconvergence is derived through the postprocessing technique. Numerical experiments are included to illustrate the feasibility of the proposed method.

  16. Using the Elements of Cooperative Learning in School Band Classes in the United States

    Science.gov (United States)

    Whitener, John L.

    2016-01-01

    The purpose of this article is to answer the question of how we might use the elements of cooperative learning in school band classes in the United States. Current school band programs use age-old traditions that overemphasize group and individual competitiveness, stress large ensemble performance at the expense of all other activities, are…

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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

  20. Cosmic rays interactions and the abundances of the chemical elements

    International Nuclear Information System (INIS)

    Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in extragalactic space. Cosmic rays come as protons, electrons, heavier nuclei, and their antiparticles. Up to energies up to some tens of TeV of particle energy it is possible to derive chemical abundances of cosmic rays. It has been proposed that cosmic ray particles can be attributed to three main sites of origin and acceleration, a) supernova shocks in the interstellar medium, b) supernova shocks in a stellar wind of the predecessor star, and c) powerful radio galaxies. This proposal leads to quantitative tests, which are encouraging so far. Quantitative models for transport and interaction appear to be consistent with the data. Li, Be, B are secondary in cosmic rays, as are many of the odd-Z elements, as well as the sub-Fe elements. At very low energies, cosmic ray particles are subject to ionization losses, which produce a steep low energy cutoff; all particles below the cutoff are moved into the thermal material population, and the particles above it remain as cosmic rays. This then changes the chemical abundances in the interstellar medium, and is a dominant process for many isotopes of Li, Be, B. With a quantitative theory for the origin of cosmic rays proposed, it appears worthwhile to search for yet better spallation cross sections, especially near threshold. With such an improved set of cross sections, the theory of the interstellar medium and its chemical abundances, both in thermal and in energetic particles, could be taken a large step forward. (author)

  1. Galactic chemical evolution of heavy elements from Barium to Europium

    CERN Document Server

    Travaglio, C; Gallino, R; Busso, M; Ferrini, F; Straniero, O

    1999-01-01

    We follow the chemical evolution of the Galaxy for elements from Ba to Eu, using an evolutionary model suitable to reproduce a large set of Galactic (local and non local) and extragalactic constraints. Input stellar yields for neutron-rich nuclei have been separated into their s-process and r-process components. The production of s-process elements in thermally pulsing asymptotic giant branch stars of low mass proceeds from the combined operation of two neutron sources: the dominant reaction 13C(alpha,n)16O, which releases neutrons in radiative conditions during the interpulse phase, and the reaction 22Ne(alpha,n)25Mg, marginally activated during thermal instabilities. The resulting s-process distribution is strongly dependent on the stellar metallicity. For the standard model discussed in this paper, it shows a sharp production of the Ba-peak elements around Z = Z_sun/4. Concerning the r-process yields, we assume that the production of r-nuclei is a primary process occurring in stars near the lowest mass lim...

  2. Laser isotope separation - a new class of chemical process

    International Nuclear Information System (INIS)

    Lasers may soon find several applications in chemical processing. The applications that have attracted the most research funding to date involve isotope separation for the nuclear industry. These isotopes have an unusually high value (≥$1000/kg) compared to bulk chemicals (∼$1/kg) and are generally required in very large quantities. In a laser isotope separation process, light is used to convert a separation that is very difficult or even impossible by conventional chemical engineering techniques to one that is readily handled by conventional separation technology. For some isotopes this can result in substantial capital and energy savings. A uranium enrichment process developed at the Lawrence Livermore National Laboratory is the closest to commercialization of the large scale laser isotope separation processes. Of particular interest to the Canadian nuclear industry are the laser separation of deuterium, tritium, zirconium-90 and carbon-14. In this paper, the basic principles behind laser isotope separation are reviewed and brief dscriptions of the more developed processes are given

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

    International Nuclear Information System (INIS)

    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∼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 6d5/2 shell and a stabilization of the 7pl/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∼Hf>Rf, in inverse order from the trend of ionic radii Rf>Zr∼Hf>Ti. An attempt was made to produce 263Rf (a) via the 248Cm(22Ne, α3n) reaction employing thenoyltrifluoroacetone (TTA) solvent extraction chemistry and (b) via the 249Bk(18O,4n) reaction employing the Automated Rapid Chemistry Apparatus (ARCA). In the TTA studies, 16 fissions were observed but were all attributed to 256Fm. No alpha events were observed in the Rf chemical fraction. A 0.2 nb upper limit production cross section for the 248Cm(22Ne, α3n)263Rf reaction was calculated assuming the 500-sec half-life reported previously by Czerwinski et al. [CZE92A

  4. Lab Astro and the Origins of the Chemical Elements

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  6. Chemical element ratios of SDSS early-type galaxies

    CERN Document Server

    Johansson, Jonas; Maraston, Claudia

    2011-01-01

    We discuss chemical enrichments of ~4000 SDSS early-type galaxies using as tracers the element abundance ratios [C/Fe], [N/Fe], [O/Fe], [Mg/Fe], [Ca/Fe] and for the first time for unresolved stellar populations [Ti/Fe]. We utilise the stellar population models of absorption line indices from Thomas, Maraston & Johansson (2011), which are based on the MILES stellar library. We confirm previous results of increasing age, [Z/H] and [O/Fe] ratios (often represented by [{\\alpha}/Fe] in the literature) with velocity dispersion. We further derive identical correlations with velocity dispersion for the abundance ratios [O/Fe], [Mg/Fe] and [C/Fe], implying that C/Mg and C/O are close to solar values. This sets a lower limit on the formation time-scales and star-burst components of early-type galaxies to ~0.4 Gyr, which is the lifetime of a 3M\\odot star, since the full C enrichment must be reached. [N/Fe] correlates with velocity dispersion, but offset to lower values and with a steeper slope compared to the other ...

  7. Theoretical chemistry for chemical identification of the heaviest elements

    Science.gov (United States)

    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. Enhancement of antibody class-switch recombination by the cumulative activity of four separate elements.

    Science.gov (United States)

    Dunnick, Wesley A; Shi, Jian; Zerbato, Jennifer M; Fontaine, Clinton A; Collins, John T

    2011-11-01

    Class-switch recombination of Ab isotype is mediated by a recombinational DNA deletion event and must be robustly upregulated during Ag-driven differentiation of B cells. The enhancer region 3' of the Cα gene is important for the upregulation of switch recombination. Using a transgene of the entire H chain C region locus, we demonstrate in this study that it is the four 3' enhancer elements themselves (a total of 4.7 kb) that are responsible for the upregulation rather than the 24 kb of DNA in between them. Neither allelic exclusion nor transgenic μ expression is reduced by deletion of the four 3' enhancers. We also test deletions of two or three of the 3' enhancers and show that deletion of more 3' enhancers results in a progressive reduction in both switch recombination and germline transcription of all H chain genes. Nevertheless, we find evidence for special roles for some 3' enhancers; different H chain genes are affected by different 3' enhancer deletions. Thus, we find that the dramatic induction of class-switch recombination during Ag-driven differentiation is the result of an interaction among four separated regulatory elements. PMID:21949022

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

    Science.gov (United States)

    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…

  10. Finite element methods for a class of continuum models for immiscible flows with moving contact lines

    CERN Document Server

    Reusken, A; Zhang, L

    2015-01-01

    In this paper we present a finite element method (FEM) for two-phase incompressible flows with moving contact lines. We use a sharp interface Navier-Stokes model for the bulk phase fluid dynamics. Surface tension forces, including Marangoni forces and viscous interfacial effects, are modeled. For describing the moving contact we consider a class of continuum models which contains several special cases known from the literature. For the whole model, describing bulk fluid dynamics, surface tension forces and contact line forces, we derive a variational formulation and a corresponding energy estimate. For handling the evolving interface numerically the level-set technique is applied. The discontinuous pressure is accurately approximated by using a stabilized extended finite element space (XFEM). We apply a Nitsche technique to weakly impose the Navier slip conditions on the solid wall. A unified approach for discretization of the (different types of) surface tension forces and contact line forces is introduced. ...

  11. AN ADI GALERKIN METHOD WITH MOVING FINITE ELEMENT SPACES FOR A CLASS OF SECOND-ORDER HYPERBOLIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An alternating-direction implicit (ADI) Galerkin nuthod with moving finite element spaces is formulated for a class of second-order hyperbolic equations in two space variables. A priori H1-error estimate is derived.

  12. An application for the presentation of the periodic system of chemical elements

    OpenAIRE

    Okrogar, Simon

    2011-01-01

    In our thesis we are going to show the development of a software. This software is intended to all who are interested in chemistry. The software is based on the periodic table of elements and offers an easily accessible description of individual chemical elements or compounds to the user. We have implemented a search for chemical compounds based on their chemical structure and enabled support for multiple users who share a personal computer. Normal users can either add, edit or remove chemica...

  13. Finite element formulation and solution of a class of contact-impact problems in contimuum mechanics

    International Nuclear Information System (INIS)

    Contact-impact phenomena are of importance in many areas of science and technlology, e.g. in nuclear reactor technology where the solution of structural problems involving contact-impact effects is crucial to the design of safe reactor systems. In recent years large-scale computational capabilities have been developed for many areas of structural analysis, the primary technique being the finite element method. At the same time, very few developments have occurred which address themselves to complicated structural problems involving contact-impact effects, and those developments which have been made are of limited generality. The reasons for this lack of development are simple: contact-impact phenomena are inherently nonlinear and the resulting problems are difficult. In this paper the results are described of a research program to develop a finite element formulation and solution procedure for contact-impact problems of a particular class which are termed Hertzian problems. Briefly, Hertzian problems are characterized by the conditions that the contact surface is approximately planar and that the contacting structures have undergone 'small' straining in the neighborhood of the contact surface. (Auth.)

  14. Immunochemical characterization of inhibitory mouse cortical neurons: Three chemically distinct classes of inhibitory cells

    OpenAIRE

    Xu, Xiangmin; Roby, Keith D.; Edward M Callaway

    2010-01-01

    The cerebral cortex has diverse types of inhibitory neurons. In rat cortex, past research has shown that parvalbumin (PV), somatostatin (SOM), calretinin (CR), and cholecystokinin (CCK) label four distinct chemical classes of GABAergic interneurons. However, in contrast to rat cortex, previous studies indicate that there is significant co-localization of SOM and CR in mouse cortical inhibitory neurons. In the present study, we further characterized immunochemical distinctions among mouse inhi...

  15. A conjecture on a class of elements of finite order in K2Fp

    Institute of Scientific and Technical Information of China (English)

    XU; Kejian

    2001-01-01

    [1] Tate, J., Relation between K2 and Galois cohomology, Invent. Math., 1976, 36: 257.[2] Suslin, A. A., Torsion in K2 of fields, K-Theory, 1987, 1: 5.[3] Moore, C., Group extensions of p-adic and adelic linear groups, Publ. Math. I .H. E. S., 1969, 35: 5.[4] Carroll, J. E., On the torsion in K2 of local fields, Lecture Notes in Math., Vol. 342, Berlin: Springer-Verlag, 1973, 464.[5] Tate, J., On the torsion in K2 of fields, Algebraic Number Theory, papers contributed for the International symposium, Kyoto 1976, 243.[6] Merkurjev, A. S., On the torsion in K2 of local fields, Annals of Mathematics, 1983, 118: 375.[7] Browkin, J., Elements of small order in K2F, Algebraic K-Theory, Lecture Notes in Math., Vol. 966, Berlin-Heidelberg-New York: Springer-Verlag, 1982, 1-6.[8] Urbanowicz, J., On elements of given orders in K2F, J. Pure. Appl. Alg., 1988, 50: 295.[9] Qin Hourong, Elements of finite order in K2F of fields, Chinese Science Bulletin, 1994, 38(24): 2227.[10] Qin Hourong, The 2-Sylow subgroups of K2OF for real quadratic fields F, Science in China (in Chinese), Ser. A, 1993, 23(12): 1254.[11] Qin Hourong, The 2-Sylow subgroups of the tame kernel of imagine quadratic fields, Acta Arith., 1995, 69: 153.[12] Qin Hourong, The 4-rank of K2OF for real quadratic fields, Acta Arith., 1995, 72: 323.[13] Qin Hourong, The subgroups of finite order in K2Q, Algebraic K-Theory and Its Application (eds. Bass, H., Kuku, A. O., Pedrini, C.), Singapore: World Scientific, 1999, 600-607.[14] Weiss, E., Algebraic Number Theory, New York: McGraw-Hill, 1963, 119-120, 185-186.[15] Iwasawa, K., Local Class Field Theory (in Chinese), Beijing: Science Press, 1986, 27-28, 129-130.[16] Neukirch, J., Class Field Theory, Berlin-Heidelberg: Springer-Verlag, 1986, 50.

  16. A semi-analytical finite element method for a class of time-fractional diffusion equations

    CERN Document Server

    Sun, HongGuang; Sze, K Y

    2011-01-01

    As fractional diffusion equations can describe the early breakthrough and the heavy-tail decay features observed in anomalous transport of contaminants in groundwater and porous soil, they have been commonly employed in the related mathematical descriptions. These models usually involve long-time range computation, which is a critical obstacle for its application, improvement of the computational efficiency is of great significance. In this paper, a semi-analytical method is presented for solving a class of time-fractional diffusion equations which overcomes the critical long-time range computation problem of time fractional differential equations. In the procedure, the spatial domain is discretized by the finite element method which reduces the fractional diffusion equations into approximate fractional relaxation equations. As analytical solutions exist for the latter equations, the burden arising from long-time range computation can effectively be minimized. To illustrate its efficiency and simplicity, four...

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

    Science.gov (United States)

    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

  18. Post-buckled precompressed (PBP) elements: a new class of flight control actuators enhancing high-speed autonomous VTOL MAVs

    OpenAIRE

    Barrett, R.; McMurtry, R.; De Vos, R; Tiso, P.; De Breuker, R.

    2005-01-01

    This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements. These actuators are designed to produce significantly higher deflection and force levels than conventional piezoelectric actuator elements. Classical laminate plate theory (CLPT) models are shown to work very well in capturing the behavior of the free, unloaded elements. A new high transverse deflection model which employs nonlinear structural relations is shown to succe...

  19. A simple and general method for solving detailed chemical evolution with delayed production of iron and other chemical elements

    OpenAIRE

    Vincenzo, Fiorenzo; Matteucci, Francesca; Spitoni, Emanuele

    2016-01-01

    In this Letter, we present a new theoretical method for solving the chemical evolution of galaxies, by assuming the instantaneous recycling approximation for chemical elements restored by massive stars and the Delay Time Distribution formalism for the delayed chemical enrichment by Type Ia Supernovae. The galaxy gas mass assembly history, together with the assumed stellar yields and initial mass function, represent the starting point of this method. We derive a very simple and general equatio...

  20. PETROS - Worldwide Databank of Major Element Chemical Analyses of Igneous Rocks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PETROS is a worldwide data bank of major element chemical analyses of igneous rocks compiled for research and teaching purposes by Dr. Felix Mutschler and Staff at...

  1. Transuranium element production. II. Chemical processing of targets

    International Nuclear Information System (INIS)

    The chemical processing described concerns small experimental targets irradiated in OSIRIS or EL-III and industrial targets irradiated in the CELESTIN reactors. In view of the difficulties encountered when processing highly irradiated targets (760MWd.kg-1) by liquid-liquid extraction (interface sludges leading to stable emulsion) the new processes developed are based on inverse phase chromatography. This technique applied to targets of americium 241, plutonium 239 and a plutonium mixture rich in isotope 242 has given tens of milligrams of curium 242, grams of americium 243 and curium 244 and micrograms of californium 252

  2. Energy-dependent existence of soliton in the synthesis of chemical elements

    OpenAIRE

    Iwata, Yoritaka

    2014-01-01

    Light chemical elements are, for instance, produced through ion collisions taking place in the core of stars, where fusion is particularly important to the synthesis of chemical elements. Meanwhile soliton provides non-interacting transparency leading to the hindrance of fusion cross section. In order to explain high fusion cross section actually observed in low incident energies, it is necessary to discover the suppression mechanism of soliton propagation. In this paper, based on a systemati...

  3. Study on the chemical species of platinum group elements in geological samples by molecular activation analysis

    International Nuclear Information System (INIS)

    The chemical species of platinum group elements in some upper mantle-derived xenoliths from Eastern China are studied by molecular activation analysis, in which the chemical stepwise dissolution, nickel fire assay preconcentration and neutron activation analysis are jointly applied. The weighted sums of platinum group elements in 6 phases are in agreement with their total contents. The distribution patterns of platinum group elements in sulphides show that sulphide segregation is one of the important mechanisms for the fractionation of platinum group elements in upper mantle-derived material during partial melting

  4. Stellar alchemy: The origin of the chemical elements

    International Nuclear Information System (INIS)

    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 developed in the 1930's. Only within the last ten years, however, have astronomical observations provided direct confirmation of these theoretical ideas. In this talk, the author describes the sequences of nuclear reactions that are believed to be responsible for power generation in stars. The ashes of these reactions are the heavy elements found on Earth and throughout the universe. The evolution and final fates of stars are examined

  5. Stellar alchemy: The origin of the chemical elements

    International Nuclear Information System (INIS)

    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

  6. Compensation of parasitic elements of transistor in the class F amplifier with the tuning of impedances at harmonics

    Directory of Open Access Journals (Sweden)

    Yefymovych A. P.

    2014-02-01

    Full Text Available The authors present a new method of construction and calculation of the output load circuit (OLC for class F power amplifiers (PA with the addition of the third harmonic of the voltage. This method allows compensating the negative influences of parasitic elements of transistor (output capacitance — COUT, and inductance — LOUT on the drain efficiency of the amplifier. The circuit of the parasitic elements was considered as a part of the proposed OLC. To calculate the OLC a system of three algebraic equations was compiled. The system is solved numerically relative to the three parameters of the OLC, for which the impedance on a chip of the transistor (on COUT for odd and even harmonics corresponds to the theory of class F PAs. This method is applicable for the calculation of the OLC, which is realized in the frequency range of 300—500 MHz, where the use of elements with lumped parameters only is not always possible, while using elements with distributed parameters leads to a substantial increase in the size of the whole amplifier. In the developed OLC, the authors used elements with both lumped and distributed parameters, thus achieving a compromise between the geometric dimensions and physical realizability of the circuit elements. The proposed OLC, taking into account the parasitic elements of the transistor, allows setting impedances independently at the first and third harmonics while maintaining impedance at the second harmonic tending to zero. This makes it possible to optimize the drain efficiency at a given level of output power. The efficiency ?d = 72,5% was experimentally obtained at POUT = 1,045 W for the class F amplifier running at 400 MHz. The proposed methodology for constructing and calculating the OLC can be used to implement class F power amplifiers in the integrated-circuit form.

  7. Measurements of radon and chemical elements: Popocatepetl volcano; Mediciones de radon y elementos quimicos: Volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Pena, P.; Segovia, N.; Lopez, B.; Reyes, A.V. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Armienta, M.A.; Valdes, C.; Mena, M. [IGFUNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Seidel, J.L.; Monnin, M. [UMR 5569 CNRS Hydrosciences, Montpellier (France)

    2002-07-01

    The Popocatepetl volcano is a higher risk volcano located at 60 Km from Mexico City. Radon measurements on soil in two fixed seasons located in the north slope of volcano were carried out. Moreover the radon content, major chemical elements and tracks in water samples of three springs was studied. The radon of soil was determined with solid detectors of nuclear tracks (DSTN). The radon in subterranean water was evaluated through the liquid scintillation method and it was corroborated with an Alpha Guard equipment. The major chemical elements were determined with conventional chemical methods and the track elements were measured using an Icp-Ms equipment. The radon on soil levels were lower, indicating a moderate diffusion of the gas across the slope of the volcano. The radon in subterranean water shown few changes in relation with the active scene of the volcano. The major chemical elements and tracks showed a stable behavior during the sampling period. (Author)

  8. Model Experiments on Chemical Properties of Superheavy Elements in Aqueous Solutions

    CERN Document Server

    Szeglowski, Z

    2003-01-01

    This paper presents a brief review of model experiments on investigation of chemical properties of transactinide elements, ranging from 104 to 116. The possibilities of isolation of the nuclei of these elements from nuclear reaction products, using the ion-exchange method, are also considered.

  9. The chemical thermodynamics of actinide elements and compounds

    International Nuclear Information System (INIS)

    This compilation forms the twelfth part of a comprehensive assessment and selection of actinide thermodynamic data. The other parts of the compilation deal mostly with actinide elements and compounds. This part, which is the last one to be published in this Series, concerns inorganic actinide complexes in aqueous solution. The properties considered include the stability constant as a function of ionic strength and temperature and, whenever possible, enthalpy and entropy values. The present assessment is based on a literature survey that was terminated in early 1989. In tabulating literature data, only experimental results were used; estimates as well as recalculated data were ignored. Unlike in previous assessments of this kind in this assessment the selection of a best value is discussed and justified, and reasons are given for the rejection of data. In addition, our estimates of the thermodynamic properties, based on interrelationships between analogous systems, are given when this can be done reliably. Another essential aim of this assessment is to indicate those areas in which additional research is required. Refs

  10. The impact of the properties of the heaviest elements on the chemical and physical sciences

    International Nuclear Information System (INIS)

    The unique role of the heaviest elements in chemical and physical sciences is discussed. With the actinide series (Z = 90-103) and the superactinide series (Z = 122-155), the heaviest elements have significantly shaped the architecture of the Periodic Table of the elements. Relativistic effects in the electron shells of the heaviest elements change the chemical properties in a given group in a non-linear fashion. Relativistically stabilized sub-shell closures give rise to a new category of elements in the Periodic Table: volatile metals. The prototype for this property is element 114 which, due to the relativistic stabilization of its 7s27p1/22 electron configuration, is volatile in its elementary state, but, in contrast to a noble gas, exhibits a marked metal-metal interaction with a gold surface at room temperature. Nuclear shell effects dominate the physical properties of the transuranium elements. These give rise to superdeformed shape isomers (fission isomers) in the actinides (U-Bk). Superheavy elements (Z ≥ 104) owe their existence solely to nuclear shell effects at N = 152, 162, and 184. At this time, a building lot is the location of the next spherical proton shell closure as there is evidence that the center of the 'island of stability' is not at Z = 114. This needs urgently further theoretical and experimental efforts. The cross sections for the syntheses of elements 119 and 120 will give us important information on the 'upper end of the Periodic Table of the elements'. (orig.)

  11. Nuclear lattice model and the electronic configuration of the chemical elements

    OpenAIRE

    Garai, Jozsef

    2011-01-01

    The fundamental organizing principle resulting in the periodic table is the nuclear charge. Arranging the chemical elements in an increasing atomic number order, a symmetry pattern known as the Periodic Table is detectable. The correlation between nuclear charge and the Periodic System of the Chemical Elements (PSCE) indicates that the symmetry emerges from the nucleus. Nuclear symmetry can only exist if the relative positions of the nucleons in the nucleus are invariant. Pauli exclusion prin...

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

    Science.gov (United States)

    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

  13. A simple and general method for solving detailed chemical evolution with delayed production of iron and other chemical elements

    CERN Document Server

    Vincenzo, Fiorenzo; Spitoni, Emanuele

    2016-01-01

    In this Letter, we present a new theoretical method for solving the chemical evolution of galaxies, by assuming the instantaneous recycling approximation for chemical elements restored by massive stars and the Delay Time Distribution formalism for the delayed chemical enrichment by Type Ia Supernovae. The galaxy gas mass assembly history, together with the assumed stellar yields and initial mass function, represent the starting point of this method. We derive a very simple and general equation which closely relates the Laplace transforms of the galaxy gas accretion and star formation history, which can be used to simplify the problem of retrieving these quantities in most of current galaxy evolution models. We find that - once the galaxy star formation history has been reconstructed from our assumptions - the differential equation for the evolution of the chemical element $X$ can be suitably solved with classical methods. We apply our model to reproduce the $[\\text{O/Fe}]$ and $[\\text{Si/Fe}]$ vs. $[\\text{Fe/...

  14. Simulation of Chemical Reactors using the Least-Squares Spectral Element method

    OpenAIRE

    Sporleder, Federico

    2011-01-01

    The least–squares spectral element method is a relatively novel method that can be used to solve any well–posed problem. It has been extensively used in computational fluid dynamics, and in recent years has been applied in the field of chemical engineering. This work focuses on the use of the least–squares spectral element method for the simulation of chemical reactors from a general point of view. The document presents an analysis on the common challenges that chemical reactor models pose an...

  15. Purposeful synthesis of chemical elements and ecologically pure mobile sources of energy

    International Nuclear Information System (INIS)

    It is well known [1] that the natural geo-transmutation of chemical elements occurs in the atmosphere and earth in the regions of a strong change in geo-, bio-, acoustic-, and electromagnetic fields. The mineral row materials contain the same accompanying chemical combinations which are independent of mineral deposit [2]. This means that the formation of chemical elements occurs in the same physical and chemical conditions. These conditions were simulated on the fundamental cooperative resonance synchronization principle [1]. The experimental facility was constructed on the basis of our model which provided with the calculated final chemical elements. These experimental results indicate new possibilities for, simulating, inducing and controlling nuclear reactions by low energy external fields. The borrowing from the geo-transmutation mechanisms of chemical elements creates the fundamental directions in low energy nuclear reaction researches for construction of new ecologically pure mobile sources of energy independent of oil, gas and coal, new substances, and technologies. References [1] F.A. Gareev, I.E. Zhidkova, E-print arXiv Nucl-th/0610002 2006. [2] V.A. Krivzskii, Transmutazija ximicheskix elementov v evolyuzii Semli (in Russian), Moscow 2003

  16. EDXRF for determination of chemical elements in the beetle Alphitobius diaperinus

    International Nuclear Information System (INIS)

    Energy Dispersion X-Ray Fluorescence (EDXRF) spectrometry has been widely employed for chemical element determination of biological matrices, including insects. The beetle Alphitobius diaperinus is a major problem in poultry production, thereby infesting poultry litter and stored grains. Up to now, little is known about the behavior, physiology and environmental interactions of this insect. In this paper, EDXRF was applied to quantify the main chemical elements in A. diaperinus. For the quality of the analytical protocol, certified reference materials produced by National Institute of Standards and Technology - NIST were analyzed together with the samples. The technique was able to quantify Cl, P, S and Zn in this insect, presenting no significant variation at the 95% confidence level among the repetitions (n = 4). A different pattern of chemical element accumulation in this beetle was noticed compared to other Coleoptera species, in which the concentration of the chemical elements were markedly lower in A. diaperinus, probably associated to the restricted availability of chemical elements in food. Since no result has been found in the literature before, A. diaperinus was firstly chemically characterized in this paper. (author)

  17. EDXRF for determination of chemical elements in the beetle Alphitobius diaperinus

    Energy Technology Data Exchange (ETDEWEB)

    Cantinha, Rebeca S.; Farias, Emerson E.G. de; Magalhaes, Marcelo L.R. de; Franca, Elvis J. de, E-mail: rebecanuclear@gmail.com, E-mail: emersonemiliano@yahoo.com.br, E-mail: marcelo_rlm@hotmail.com, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Cunha, Franklin M. da; Zacarias, Vyvyane L., E-mail: ukento@yahoo.com.br, E-mail: vyvyanebiologicas@gmail.com [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil)

    2015-07-01

    Energy Dispersion X-Ray Fluorescence (EDXRF) spectrometry has been widely employed for chemical element determination of biological matrices, including insects. The beetle Alphitobius diaperinus is a major problem in poultry production, thereby infesting poultry litter and stored grains. Up to now, little is known about the behavior, physiology and environmental interactions of this insect. In this paper, EDXRF was applied to quantify the main chemical elements in A. diaperinus. For the quality of the analytical protocol, certified reference materials produced by National Institute of Standards and Technology - NIST were analyzed together with the samples. The technique was able to quantify Cl, P, S and Zn in this insect, presenting no significant variation at the 95% confidence level among the repetitions (n = 4). A different pattern of chemical element accumulation in this beetle was noticed compared to other Coleoptera species, in which the concentration of the chemical elements were markedly lower in A. diaperinus, probably associated to the restricted availability of chemical elements in food. Since no result has been found in the literature before, A. diaperinus was firstly chemically characterized in this paper. (author)

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

    Science.gov (United States)

    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…

  19. Reactive chemically modified piezoelectric crystal detectors: A new class of high-selectivity sensors

    International Nuclear Information System (INIS)

    A great number of works have focused on the study of properties of modified piezoelectric quartz crystal detectors (PQCDs) coated with sorbing substrates and on applying sensors based on them for the analysis of diluted gas mixtures and solutions. This work offers a new class of gravemetric sensors characterized by a reversible chemical reaction that occurs on their surface. Silica films are proposed as a sorbing coating of quartz detectors, and a chemical modification of a surface is suggested for covalent fixation of the necessary compounds. PQCDs were chemically modified with reactive diene derivatives that can also act as dienophiles. Hexachlorocyclopentadiene (HCCPD, resonater I) and cyclopentadiene (CPD, resonator II) were fixed on a PQCD surface in several stages. After treatment with the resonaters, the PQCD in a CPD gas phase exhibited time dependent frequency shifts from 20-100 Hz. The results suggest that there is a reversible chemical reaction on the electrode surface of resonators I and II when they interact with CPD vapors. Therefore, PQCDs modified with reactive dienes were prepared for the first time and may be employed as selective sensors for CPD

  20. WHICH CHEMISTRY TEACH? REFLECTIONS ABOUT THE CHEMICAL EDUCATION AND FORMATION OF READERS IN CLASSES OF CHEMISTRY IN SECONDARY EDUCATION

    Directory of Open Access Journals (Sweden)

    Cristhiane Cunha Flôr

    2016-04-01

    Full Text Available This study addresses issues related to some approaches given to chemical education in high school. This is a theoretical reflection that adresses aspects to be considered when working with readings in this context, as the question of the specificity of chemical language, approaches related to the daily lives of students and training of readers in chemistry classes.

  1. Assessment of serum biomarkers in rats after exposure to pesticides of different chemical classes

    International Nuclear Information System (INIS)

    There is increasing emphasis on the use of biomarkers of adverse outcomes in safety assessment and translational research. We evaluated serum biomarkers and targeted metabolite profiles after exposure to pesticides (permethrin, deltamethrin, imidacloprid, carbaryl, triadimefon, fipronil) with different neurotoxic actions. Adult male Long–Evans rats were evaluated after single exposure to vehicle or one of two doses of each pesticide at the time of peak effect. The doses were selected to produce similar magnitude of behavioral effects across chemicals. Serum or plasma was analyzed using commercial cytokine/protein panels and targeted metabolomics. Additional studies of fipronil used lower doses (lacking behavioral effects), singly or for 14 days, and included additional markers of exposure and biological activity. Biomarker profiles varied in the number of altered analytes and patterns of change across pesticide classes, and discriminant analysis could separate treatment groups from control. Low doses of fipronil produced greater effects when given for 14 days compared to a single dose. Changes in thyroid hormones and relative amounts of fipronil and its sulfone metabolite also differed between the dosing regimens. Most cytokine changes reflected alterations in inflammatory responses, hormone levels, and products of phospholipid, fatty acid, and amino acid metabolism. These findings demonstrate distinct blood-based analyte profiles across pesticide classes, dose levels, and exposure duration. These results show promise for detailed analyses of these biomarkers and their linkages to biological pathways. - Highlights: • Pesticides typical of different classes produced distinct patterns of change in biomarker panels. • Based on the panels used, alterations suggest impacts on immune, metabolism, and homeostasis functions. • Some changes may reflect actions on neurotransmitter systems involved in immune modulation. • Fipronil effects on thyroid and kinetics

  2. Assessment of serum biomarkers in rats after exposure to pesticides of different chemical classes

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Virginia C., E-mail: Moser.ginger@epa.gov [Neurotoxicology Branch/Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Stewart, Nicholas; Freeborn, Danielle L. [Neurotoxicology Branch/Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Crooks, James; MacMillan, Denise K. [Analytical Chemistry Research Core/Research Cores Unit, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Hedge, Joan M.; Wood, Charles E. [Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); McMahen, Rebecca L. [ORISE fellow, Human Exposure and Atmospheric Sciences Division, National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Strynar, Mark J. [Human Exposure and Atmospheric Sciences Division, National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Herr, David W. [Neurotoxicology Branch/Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)

    2015-01-15

    There is increasing emphasis on the use of biomarkers of adverse outcomes in safety assessment and translational research. We evaluated serum biomarkers and targeted metabolite profiles after exposure to pesticides (permethrin, deltamethrin, imidacloprid, carbaryl, triadimefon, fipronil) with different neurotoxic actions. Adult male Long–Evans rats were evaluated after single exposure to vehicle or one of two doses of each pesticide at the time of peak effect. The doses were selected to produce similar magnitude of behavioral effects across chemicals. Serum or plasma was analyzed using commercial cytokine/protein panels and targeted metabolomics. Additional studies of fipronil used lower doses (lacking behavioral effects), singly or for 14 days, and included additional markers of exposure and biological activity. Biomarker profiles varied in the number of altered analytes and patterns of change across pesticide classes, and discriminant analysis could separate treatment groups from control. Low doses of fipronil produced greater effects when given for 14 days compared to a single dose. Changes in thyroid hormones and relative amounts of fipronil and its sulfone metabolite also differed between the dosing regimens. Most cytokine changes reflected alterations in inflammatory responses, hormone levels, and products of phospholipid, fatty acid, and amino acid metabolism. These findings demonstrate distinct blood-based analyte profiles across pesticide classes, dose levels, and exposure duration. These results show promise for detailed analyses of these biomarkers and their linkages to biological pathways. - Highlights: • Pesticides typical of different classes produced distinct patterns of change in biomarker panels. • Based on the panels used, alterations suggest impacts on immune, metabolism, and homeostasis functions. • Some changes may reflect actions on neurotransmitter systems involved in immune modulation. • Fipronil effects on thyroid and kinetics

  3. Interaction of chemical species with biological regulation of the metabolism of essential trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, W. [Center of Life and Food Sciences, Technische Univ. Muenchen, Freising (Germany)

    2002-02-01

    Variations in the chemical speciation of dietary trace elements can result in the provision of different amounts of these micronutrients to the organism and might thus induce interactions with trace-element metabolism. The chemical species of Zn, Fe, Cu, and Mn can interact with other components of the diet even before reaching the site of absorption, e.g. by formation of poorly soluble complexes with phytic acid. This might considerably modify the amount of metabolically available trace elements; differences between absorptive capacity per se toward dietary species seems to be less important. Homeostasis usually limits the quantities of Zn, Fe, Cu, and Mn transported from the gut into the organism, and differences between dietary species are largely eliminated at this step. There is no homeostatic control of absorption of Se and I, and organisms seem to be passively exposed to influx of these micronutrients irrespective of dietary speciation. Inside the organism the trace elements are usually converted into a metabolically recognizable form, channeled into their biological functions, or submitted to homeostatically controlled excretion. Some dietary species can, however, be absorbed as intact compounds. As long as the respective quantities of trace elements are not released from their carriers, they are not recognized properly by trace element metabolism and might induce tissue accumulation, irrespective of homeostatic control. (orig.)

  4. Some chemical elements in gamma irradiated adults of the mediterranean fruit fly , Ceratitis Capitata (WIED.)

    International Nuclear Information System (INIS)

    The chemical analysis of the elemental compositions of both males and females of the Mediterranean fruit fly, Ceratitis capitata (Wied.), was conducted on adult flies irradiated in the full grown pupae with 50, 70, 90 and 110 Gray at different ages (newly emerged, 7 and 15 days old). The data revealed the presence of ten elements, three of which are major (Na, K and N), four are moderate (P, Ca, Fe and Mg) and three are minors (Zn, Mn and Cu). Their quantities, however, varied according to adult sex, age and radiation dose. In all cases, the major elements remained major, the moderate elements remained moderate and the minor elements remained minor although the elements of each group differed in their arrangement according to changes in their quantities

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  7. Features of a Spatial Distribution of Dust Masses and Adsorbed Chemical Elements in Filters of NPPs

    International Nuclear Information System (INIS)

    The features of an adsorption from air of chemical elements and their isotopes in carbon filters AU-1500 of atomic power plants are clarified. It is shown that the nonuniform allocation of elements inside a filter retrieved earlier by a method of a gamma-activation analysis, well correlates with features of allocation of dust masses researched by the authors. This circumstance indicates the important role of dust fractions of adsorbent placed in a filter, in an adsorption of elements and their isotopes. The physical reasons resulting in to such character of interaction by portable air elements with dust accumulations are surveyed. The analysis of influence of these processes on serviceability of filters and saving of the accumulated material are considered

  8. On a group-theoretical approach to the periodic table of chemical elements

    OpenAIRE

    Kibler, Maurice

    2004-01-01

    This paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from the table and the general lines of a programme for a quantitative approach to the properties of chemical elements are developed on the basis of the gro...

  9. Regular Elements of the Complete Semigroups BX(D of Binary Relations of the Class ∑2(X,8

    Directory of Open Access Journals (Sweden)

    Nino Tsinaridze

    2015-03-01

    Full Text Available As we know if D is a complete X-semilattice of unions then semigroup Bx(D possesses a right unit iff D is an XI-semilattice of unions. The investigation of those a-idempotent and regular elements of semigroups Bx(D requires an investigation of XI-subsemilattices of semilattice D for which V(D,a=Q∈∑2(X,8 . Because the semilattice Q of the class ∑2(X,8 are not always XI -semilattices, there is a need of full description for those idempotent and regular elements when V(D,a=Q . For the case where X is a finite set we derive formulas by calculating the numbers of such regular elements and right units for which V(D,a=Q .

  10. Soil-leaf transfer of chemical elements for the Atlantic Forest

    International Nuclear Information System (INIS)

    Soil analysis could improve environmental studies since soil is the main source of chemical elements for plants. In this study, soil samples collected at 0-10 cm depth under tree crown projection were analyzed by INAA. Using the chemical composition of the leaf previously determined, the leaf-soil transfer factors of chemical elements could be estimated for the Atlantic Forest. Despite the variability of the intra-species, the transfer factors were specific for some plant species due to their element accumulation in the leaves. Similar Br-Zn combined transfer factors were obtained for the species grouped according to habitats in relation to their position (understory or dominant species) in the forest canopy. (author)

  11. A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments

    OpenAIRE

    Kibler, M. R.

    2005-01-01

    This paper is a companion article to the review paper by the present author devoted to the classification of matter constituents (chemical elements and particles) and published in the first part of the proceedings of The Second Harry Wiener International Memorial Conference (see quant-ph/0310155). It is mainly concerned with a group-theoretical approach to the Periodic Table of the neutral elements based on the noncompact group SO(4,2)xSU(2).

  12. Losing identity: structural diversity of transposable elements belonging to different classes in the genome of Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Fernández-Medina Rita D

    2012-06-01

    Full Text Available Abstract Background Transposable elements (TEs, both DNA transposons and retrotransposons, are genetic elements with the main characteristic of being able to mobilize and amplify their own representation within genomes, utilizing different mechanisms of transposition. An almost universal feature of TEs in eukaryotic genomes is their inability to transpose by themselves, mainly as the result of sequence degeneration (by either mutations or deletions. Most of the elements are thus either inactive or non-autonomous. Considering that the bulk of some eukaryotic genomes derive from TEs, they have been conceived as “TE graveyards.” It has been shown that once an element has been inactivated, it progressively accumulates mutations and deletions at neutral rates until completely losing its identity or being lost from the host genome; however, it has also been shown that these “neutral sequences” might serve as raw material for domestication by host genomes. Results We have analyzed the sequence structural variations, nucleotide divergence, and pattern of insertions and deletions of several superfamilies of TEs belonging to both class I (long terminal repeats [LTRs] and non-LTRs [NLTRs] and II in the genome of Anopheles gambiae, aiming at describing the landscape of deterioration of these elements in this particular genome. Our results describe a great diversity in patterns of deterioration, indicating lineage-specific differences including the presence of Solo-LTRs in the LTR lineage, 5′-deleted NLTRs, and several non-autonomous and MITEs in the class II families. Interestingly, we found fragments of NLTRs corresponding to the RT domain, which preserves high identity among them, suggesting a possible remaining genomic role for these domains. Conclusions We show here that the TEs in the An. gambiae genome deteriorate in different ways according to the class to which they belong. This diversity certainly has implications not only at the host

  13. Stars, Galaxies, and the Origin of Chemical Elements

    Science.gov (United States)

    Peter, Ulmschneider

    "That I am mortal I know, and that my days are numbered, but when in my mind I follow the multiply entwined orbits of the stars, then my feet do no longer touch the Earth. At the table of Zeus himself do I eat Ambrosia, the food of the Gods". These words by Ptolemy from around 125 A.D. are handed down together with his famous book The Almagest, the bible of astronomy for some 1500 years. They capture mankind's deep fascination with the movements of the heavens, and the miracles of the biological world. After the Babylonians observed the motions of the Sun, Moon, and planets for millennia, the ancient Greeks were the first to speculate about the nature of these celestial bodies. Yet it is only as a consequence of developments in the last 150 years that a much clearer picture of the physical universe has begun to emerge. Among the most important discoveries have been the stellar parallax, confirming Copernicus's heliocentric system, the realization that galaxies are comprised of billions of stars, the awareness of the size of the universe, and the evolutionary nature of living organisms.

  14. Scientific Realism and the Periodic Table of Chemical Elements

    OpenAIRE

    Sides, Jonathan David

    2006-01-01

    The periodic table poses a difficulty for both scientific realists and anti-realists. The antirealist has difficulty accounting for the success of the table during a period in chemistry when many theories and concepts changed; the spatial relations of current tables in use do not show fundamental changes from the original tables proposed by Mendeleev. Yet, most versions of scientific realism are based upon the understanding that theories are some collection of written propositi...

  15. Chemical Elements Abundance in the Universe and the Origin of Life

    CERN Document Server

    Valkovic, Vlado

    2016-01-01

    Element synthesis which started with p-p chain has resulted in several specific characteristics including lack of any stable isotope having atomic masses 5 or 8. The carbon to oxygen ratio is fixed early by the chain of coincidences. These, remarkably fine-tuned, conditions are responsible for our own existence and indeed the existence of any carbon based life in the Universe. Chemical evolution of galaxies reflects in the changes of chemical composition of stars, interstellar gas and dust. The evolution of chemical element abundances in a galaxy provides a clock for galactic aging. On the other hand, the living matter on the planet Earth needs only some elements for its existence. Compared with element requirements of living matter a hypothesis is put forward, by accepting the Anthropic Principle, which says: life as we know, (H-C-N-O) based, relying on the number of bulk and trace elements originated when two element abundance curves, living matter and galactic, coincided. This coincidence occurring at part...

  16. Physical and chemical behavior of elements in uranium waste. 3

    International Nuclear Information System (INIS)

    Thermodynamic behavior of UF6 conversion was studied. From the results of theoretical calculations on the conversion from UF6 to UO2, the following reactions were thought to generate; UF6 + 2H2O = UO2F2 + 4HF (a), UO2F2 + H2 = 1/2UF4 + 1/2UO2 + H2O (b) and 1/2UF4 + H2O 1/2UO2 + 2HF (c) instead of UF6 + 2H2O = UO2F2 + 4HF (1), UO2 + H2O UO3 + 2HF (2) and UO3 + H2 = UO2 + H2O (3). UO2F2 is obtained easily by the hydrolysis of UF6. The appropriate temperature for hydrogen reduction of UO2F2 and water vapor oxidation of UF4 is more than 500 K and 950 K, respectively. Some experiments were carried out by a small reactor in order to confirm the above reaction (b). However, UO3 was produced without UO2 and UF4. This fact showed existence of oxygen. UO2F2 is hygroscopic and deliquescent. When UO2F2 was feed to the reactor, it contacted with air and UO2 was oxidized to UO3. (S.Y.)

  17. Application of data mining tools for classification of protein structural class from residue based averaged NMR chemical shifts.

    Science.gov (United States)

    Kumar, Arun V; Ali, Rehana F M; Cao, Yu; Krishnan, V V

    2015-10-01

    The number of protein sequences deriving from genome sequencing projects is outpacing our knowledge about the function of these proteins. With the gap between experimentally characterized and uncharacterized proteins continuing to widen, it is necessary to develop new computational methods and tools for protein structural information that is directly related to function. Nuclear magnetic resonance (NMR) provides powerful means to determine three-dimensional structures of proteins in the solution state. However, translation of the NMR spectral parameters to even low-resolution structural information such as protein class requires multiple time consuming steps. In this paper, we present an unorthodox method to predict the protein structural class directly by using the residue's averaged chemical shifts (ACS) based on machine learning algorithms. Experimental chemical shift information from 1491 proteins obtained from Biological Magnetic Resonance Bank (BMRB) and their respective protein structural classes derived from structural classification of proteins (SCOP) were used to construct a data set with 119 attributes and 5 different classes. Twenty four different classification schemes were evaluated using several performance measures. Overall the residue based ACS values can predict the protein structural classes with 80% accuracy measured by Matthew correlation coefficient. Specifically protein classes defined by mixed αβ or small proteins are classified with >90% correlation. Our results indicate that this NMR-based method can be utilized as a low-resolution tool for protein structural class identification without any prior chemical shift assignments. PMID:25758094

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

    International Nuclear Information System (INIS)

    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

  19. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Moghaddas

    2013-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  20. A new-generation density functional towards chemical accuracy for chemistry of main group elements

    CERN Document Server

    Zhang, Igor Ying

    2013-01-01

    A New-Generation Density Functional: Towards Chemical Accuracy for Chemistry of Main Group Elements covers the most recent progress in the development of a new generation of density functional theory (DFT) for accurate descriptions of thermochemistry, thermochemical kinetics, and nonbonded interactions of main group molecules.

  1. The study of spatial redistribution of chemical elements in coupling of marshy woodlands (poles'e) types of landscapes

    International Nuclear Information System (INIS)

    Geochemical spectrum analysis of spatial redistribution of chemical elements in top-soil allows to draw a conclusion that peaty-podzol-gley alluvial-ferriferous soil H-H-Fe/TC/fg-geosystem takes place reducing of chemical elements content in comparison with coupling elementary landscapes

  2. Frontiers of the heaviest elements - towards an understanding of the physical and chemical behaviour of the elements

    International Nuclear Information System (INIS)

    The description of the chemical behaviour of the heaviest elements has directly to do with a good relativistic description. In the limit of very low charges (at the beginning of the Periodic System) the non-relativistic description looks of course very much like the relativistic description and the problem is that we have learned to think in terms of the solution of the non-relativistic Schroedinger equation. In the first part I will therefore try to discuss the difference between the non-relativistic and the relativistic description. The talk has been structured as follows: first a brief discussion is given for the relativistic effects of 1-electron atoms which then will be extended to many-electron atoms. In the third section relativistic calculations of molecules will be discussed. (author)

  3. Use of chemical elements of 1A family by tropical tree species

    International Nuclear Information System (INIS)

    This study aims to evaluate the distribution of K, Rb and Cs in leaves of trees of the Atlantic Forest through studies of correlation between the chemical elements. For this, we used the Instrumental Neutron Activation Analysis for the quantification of the chemical elements. The concentration ranges found were 6700-24000 mg / kg for K, 16 to 72mg / kg for Rb and 0.08 to 0,92mg / kg for Cs. As Rb has chemical similarity to K, is easily absorbed by plants, leading to a high value (0.9) of the Pearson correlation. For the correlation between K and Cs, no significant values were detected except for some species of the Myrtaceae family. However, average correlations (0.6 < r <0.8) between Rb-Cs were obtained for seven plant species of different families. The absence of a specific pattern using of K, Rb and Cs by plants showed great complexity in the distribution of chemical elements in the ecosystem

  4. Behavior of radon, chemical compounds and stable elements in underground water

    International Nuclear Information System (INIS)

    The radon behavior, chemical compounds, major and trace elements in water samples of four springs and three wells of urban and agricultural zones around the Jocotitlan volcano and El Oro region was determined, both of them located in the medium part of the Mexican neo-volcanic axis. The 222 Rn was measured by the liquid scintillation method, the analysis of major components was realized with conventional chemical techniques, while the trace elements were quantified using an Icp-Ms. The average values of the radon concentrations obtained during one year were constant relatively, in an interval from 0.97 to 4.99 Bq/lt indicating a fast transport from the reload area toward the sampling points. the compounds, major and trace elements showed differences which indicate distinct origins of water from the site studies. (Author)

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

    Science.gov (United States)

    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.

  6. A Review of Class I and Class II Pet Food Recalls Involving Chemical Contaminants from 1996 to 2008

    OpenAIRE

    Rumbeiha, Wilson; Morrison, Jamie

    2010-01-01

    Commercial pet food in USA is generally safe, but adulteration does occur. Adulterated food has to be recalled to protect pets and public health. All stakeholders, including food firms, distributors, and government agencies such as the Food and Drug Administration (FDA) participate in food recall. The objective of this review is to describe the pet food recall procedure from start to finish, and to review class I and II pet food recalls from 1996 to 2008, with a specific focus on those due to...

  7. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    International Nuclear Information System (INIS)

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration

  8. Impact of chemical elements on heart failure progression in coronary heart disease patients

    Directory of Open Access Journals (Sweden)

    Cherniavsky Aleksander

    2011-05-01

    Full Text Available Background. The high prevalence, poor prog-nosis of patients with coronary heart disease with chronic heart failure determine the relevance of the study pathophysiological and molecular mechanisms of this pathology. Researches of the trace element metabolism in the myocardium are scarce. With this in mind, an attempt was made to analyze the relationship of macro and trace elements metabolism with the functional state of the myocardium in coronary heart disease patients against the background of chronic heart failure progression. Methods and Results. To study the content of the chemical elements (S, K, Ca, Cr, Fe, Ni, Cu, Zn, Se, Rb, Sr in the myocardium of 43 patients with coronary heart disease, use was made of X-ray fluorescence with synchrotron radiation. While doing autopsy, 43 samples of left ventricle myocardium were taken off the cardiac callosity. Myocardium samples were subjected to histological examination. Dynamics of macro and trace elements content in the myocardium reflects the development of energy deficiency and disorders of myocardial microcirculation with a decrease of systolic myocardial function. Structural/functional disorders in the myocardium of the left ventricle of patients with coronary heart disease that accompany the progression of chronic heart failure are associated with profound changes of metabolic processes in heart muscle. Conclusions. The structural/ functional changes accompanying chronic heart failure progression are associated with wide variations of metabolic processes in the myocardium, which could be evaluated by the content of chemical elements in tissue.

  9. Quantitative analysis of chemical elements in single cells using nuclear microprobe and nano-probe

    International Nuclear Information System (INIS)

    The study of the role of trace elements at cellular level requires the use of state-of-the-art analytical tools that could achieve enough sensitivity and spatial resolution. We developed a new methodology for the accurate quantification of chemical element distribution in single cells based on a combination of ion beam analysis techniques STIM, PIXE and RBS. The quantification procedure relies on the development of a STIM data analysis software (Paparamborde). Validity of this methodology and limits are discussed here. The method allows the quantification of trace elements (μg/g) with a 19.8 % uncertainty in cellular compartments with mass below 0.1 ng. The main limit of the method lies in the poor number of samples that can be analyzed, due to long irradiation times required and limited access to ion beam analysis facilities. This is the reason why we developed a database for cellular chemical composition capitalization (BDC4). BDC4 has been designed in order to use cellular chemical composition as a tracer for biological activities and is expected to provide in the future reference chemical compositions for any cellular type or compartment. Application of the STIM-PIXE-RBS methodology to the study of nuclear toxicology of cobalt compounds is presented here showing that STIM analysis is absolutely needed when organic mass loss appears during PIXE-RBS irradiation. (author)

  10. EDXRF applied to the chemical element determination of small invertebrate samples

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de, E-mail: marcelo_rlm@hotmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: rebecanuclear@gmail.com, E-mail: thomasmarques@live.com.pt, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E{sub n} Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

  11. EDXRF applied to the chemical element determination of small invertebrate samples

    International Nuclear Information System (INIS)

    Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the En Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

  12. Micro Chemical (Elemental Analysis of Leucas aspera (Willd Link Employing SEM-EDAX

    Directory of Open Access Journals (Sweden)

    Sunkara Yashvanth

    2013-01-01

    Full Text Available The plant, Leucas aspera (Willd Link is well known for its varied medicinal uses. Present study deals with its micro chemical (elemental characterization using Energy Dispersive X-ray Analysis (EDAX detector fitted to Scanning Electron Microscope. The plant has very interesting morphology. Crystals of varied shape and inclusions/exudates were noticed within and on the leaf & stem surfaces. Various plant parts analysed were, stem surface, stem sections, stem inclusions, blebs on stem hairs, crystals of varied shape, root sections, abaxial and adaxial surfaces, flower, seed and seed caruncle. Lot of variation in elemental composition was observed in various plant parts. Major elements detected were Carbon, Oxygen, Calcium, Silica, and Aluminum. Other elements found were Iron, Sodium, potassium, Phosphorus and Chlorine.

  13. Influence of ironworks on distribution of chemical elements in Bosnia and Herzegovina and Slovenia

    Directory of Open Access Journals (Sweden)

    Jasminka Alijagić

    2006-06-01

    Full Text Available The objective of this work is the study of the distribution of chemical elements in attic dust and topsoil for the identification of anthropogenic and geogenic element sources in an old metallurgic area in Bosnia and Herzegovina and Slovenia (Slo – BiH bilateral project “Heavy metals in environment as consequences of mining and smelting in the past”. Samples of attic dust and topsoil were collected in localities in BiH (Zenica, Vareš and Ilijaš and Slovenia (Jesenice, Štore and Ravne.Analysis for 42 chemical elements was performed. Based on a comparison of statistical parameters, spatial distribution of particular elements and results of cluster analysis one natural and two anthropogenic geochemical associations were identified. The natural geochemical association (Al-K-La-Sc-Th-Ti is influenced mainly by lithology. The anthropogenic association (Co-Cr-Mo-Ni-V-W is the result of iron metallurgy in the past. The second anthropogenic association (Ag-As-Cd-Fe-Hg-Mn-Pb-Sb-Sn-Zn is the result of high level of sulphide phase in iron ore (Vareš and zinc and sulphuric acid production in the Celje area.

  14. Chemical properties of some elements in a molten lithium chloride, potassium chloride eutectic (1962)

    International Nuclear Information System (INIS)

    The increasing use of molten media especially in chemical preparations and for certain technological applications, has made it more necessary to have a knowledge of the chemical properties of elements in these solvents. Structural studies on molten solutions show the existence of certain species such as ions and complexes known to exist in aqueous solutions. This fact, together with certain experiments on chemical reactions in molten media has led us to establish a comparison between these media and aqueous solutions. We wish to show that the same fundamental phenomena occur in these media as are found in the chemistry of aqueous solutions and that this makes it possible to predict certain reactions. We have taken as examples the chemical properties of vanadium, uranium and sulphur in a LiCl-KCl eutectic melted at 480 deg. C. The first problem is to identify the various degrees of oxidation of these elements existing in the solvent chosen. We have tried to resolve it by comparing the absorption spectra obtained in aqueous solution and in the molten eutectic. We consider the possibilities of this method in a chapter on absorption spectrophotometry in the LiCl-KCl eutectic. During the study of the chemical properties we stress the various methods of displacing the equilibria: complex formation, variation of the oxidation-reduction properties with complex formation. The complexes of the O2- ion are considered in particular. The study of the exchange of this particle is facilitated by the use of a classification of some of its complexes which we call the pO2- scale by analogy with the pH scale; the value pO2- is defined by the relationship: pO2- = log O2- Similarly, the use of apparent potential diagrams pO2- makes it possible to predict and to interpret reactions involving the simultaneous exchange of electrons and O2- ions between the various degrees of oxidation of the same element. It is possible, by studying some reactions of this type between two elements. We

  15. Chemical element transfer of weathering granite regolith in the Three Gorges Dam region of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Clearing up sediment and regolith on the foundation of the dam in the Three Gorges of the Yangtze River in 1999, riverbed were exposed. On the basis of weathering granite regolith sampled from different portions of the valley landforms, by analysing total chemical contents with X rays fluorescent slice and calculating proper value of chemical element transferring ratio and intensity, the transferring law of chemical elements in different portions of the landforms were concluded: 1) In various landforms of the river valley, the process of desilication is not distinct; 2) in weathering granite regolith of riverbed, easy soluble CaO and MgO are relatively enriched whereas A1203 tends to decrease. The enriching rate of Fe203 is the greatest in various landforms of the river valley; 3) in weathering granite regolith of flood-plain, K20 and MgO contents are relatively enriched; 4) the weathering granite regolith of valley slope is a typical north subtropical weathering regolith, and its chemical weathering degree is in the transition phase from early to middle period; and 5) there is an opposite layer where K20 is relatively leaching and Na20 relatively enriching in 6.5 m depth of all weathering granite regolith.

  16. DETERMINATION OF CHEMICAL CLASSES FROM MASS SPECTRA OF TOXIC ORGANIC COMPOUNDS BY SIMCA PATTERN RECOGNITION AND INFORMATION THEORY

    Science.gov (United States)

    The low resolution mass spectra of a set of 78 toxic volatile organic compounds were examined for information concerning chemical classes. These compounds were predominately chloro- and/or bromoaromatics, -alkanes, or -alkenes, which are routinely sought at trace levels in ambien...

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Chemical properties of the transactinide elements studied in liquid phase with SISAK

    International Nuclear Information System (INIS)

    This article starts with a review of the current SISAK liquid-liquid extraction system, as used after the physical preseparator BGS at LBNL for chemical studies of transactinide elements. Emphasis will be on new additions and developments. Then the possibilities offered by the new TASCA separator at GSI and the use of actinide targets at both GSI and LBNL are discussed with respect to future SISAK transactinide experiments. Finally, current and future liquid-liquid extraction systems for studying elements Rf up to Hs are discussed

  1. Chemical properties of the trans-actinide elements studied in liquid phase with SISAK

    Energy Technology Data Exchange (ETDEWEB)

    Omtvedt, J.P.; Alstad, J.; Bjornstad, T.; Opel, K.; Polakova, D.; Samadani, F.; Schulz, F.; Stavsetra, L.; Zheng, L. [Oslo Univ., Centre for Accelerator based Research and Energy Physics (SAFE) (Norway); Dullmann, Ch.E; Gregorich, K.E.; Hoffman, D.C.; Nitsche, H.; Sudowe, R. [Lawrence Berkeley National Laboratory (LBNL), Nuclear Science Div., One Cyclotron Road, Berkeley, CA (United States); Dullmann, Ch.E.; Hoffman, D.C.; Nitsche, H. [California Univ., Dept. of Chemistry, Berkeley, CA (United States); Skarnemark, G. [Chalmers Univ. of Technology, Nuclear Chemistry, Dept. of Chemical and Biological Engineering (Sweden)

    2007-10-15

    This article starts with a review of the current SISAK liquid-liquid extraction system, as used after the physical pre-separator BGS (Berkeley Gas-filled Separator) at Lawrence Berkeley National Laboratory (LBNL) for chemical studies of trans-actinide elements. Emphasis will be on new additions and developments. Then the possibilities offered by the new TASCA (Trans-Actinide Separator and Chemistry Apparatus) separator at GSI (Darmstadt, Germany) and the use of actinide targets at both GSI and LBNL are discussed with respect to future SISAK trans-actinide experiments. Finally, current and future liquid-liquid extraction systems for studying elements Rutherfordium up to Hassium are discussed. (authors)

  2. Chemical properties of the trans-actinide elements studied in liquid phase with SISAK

    International Nuclear Information System (INIS)

    This article starts with a review of the current SISAK liquid-liquid extraction system, as used after the physical pre-separator BGS (Berkeley Gas-filled Separator) at Lawrence Berkeley National Laboratory (LBNL) for chemical studies of trans-actinide elements. Emphasis will be on new additions and developments. Then the possibilities offered by the new TASCA (Trans-Actinide Separator and Chemistry Apparatus) separator at GSI (Darmstadt, Germany) and the use of actinide targets at both GSI and LBNL are discussed with respect to future SISAK trans-actinide experiments. Finally, current and future liquid-liquid extraction systems for studying elements Rutherfordium up to Hassium are discussed. (authors)

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

    Science.gov (United States)

    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.

  4. Chemical evolution with bursts of star formation - Element ratios in dwarf galaxies

    International Nuclear Information System (INIS)

    It is demonstrated that galaxies in which star formation proceeds in a small number of bursts evolve their chemical elements in ratios which are very different from those in galaxies with continuing star formation. Systematic changes of element ratios with overall chemical abundance are determined to a large extent by the onset and duration of the star formation bursts and can be very different from those seen in the solar neighborhood. In particular, it is shown that an underabundance of oxygen relative to iron, such as is observed in the Large Magellanic Cloud, occurs naturally when star formation proceeds in a small number of widely separated bursts, as is inferred from the age distribution of LMC field stars and clusters. There is no need to invoke either variations in the stellar initial mass function or metal-enhanced winds. 25 refs

  5. Dynamics of chemical elements in the fermentation process of ethanol production

    International Nuclear Information System (INIS)

    Brazil has become the largest producer of biomass ethanol derived from sugar cane. The industrial production is based on the fermentation of sugar cane juice by yeast, inside of large volume vats, in a fed-batch process that recycles yeast cells. To study the dynamics of chemical elements in each operating cycle, five stages of the fermentation process were considered: must, yeast suspension, wine, non-yeast wine and yeast cream. For this, a mass balance of the terrigenous elements, Ce, Co, Cs, Eu, Fe, Hf, La, Na, Sc, Sm, and Th, and the sugar cane plant elements, Br, K, Rb, and Zn, were established in fermentation vats of an industrial scale unit, with sampling undertaken during different climatic conditions (dry and rainy periods). A similar distribution of the sugar cane characteristics elements was found for the stages analysed, while for the terrigenous elements a trend of accumulation in the yeast cream was observed. Preferential absorption of Br, K, Rb, and Zn by yeast cells was indicated by the smaller concentrations observed in yeast suspension than in yeast cream. (author)

  6. Chemical properties of the transactinide elements studied in liquid phase with SISAK

    OpenAIRE

    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.

    2008-01-01

    This article starts with a review of the current SISAK liquid-liquid extraction system, as used after the physical preseparator BGS at LBNL for chemical studies of transactinide elements. Emphasis will be on new additions and developments. Then the possibilities offered by the new TASCA separator at GSI and the use of actinide targets at both GSI and LBNL are discussed with respect to future SISAK transactinide experiments. Finally, current and future liquid-liquid extraction systems for...

  7. Features of adsorbed radioactive chemical elements and their isotopes distribution in iodine air filters AU-1500 at nuclear power plants

    CERN Document Server

    Neklyudov, I M; Dikiy, N P; Ledenyov, O P; Lyashko, Yu V

    2013-01-01

    The main aim of research is to investigate the physical features of spatial distribution of the adsorbed radioactive chemical elements and their isotopes in the granular filtering medium in the iodine air filters of the type of AU1500 in the forced exhaust ventilation systems at the nuclear power plant. The gamma activation analysis method is applied to accurately characterize the distribution of the adsorbed radioactive chemical elements and their isotopes in the granular filtering medium in the AU1500 iodine air filter after its long term operation at the nuclear power plant. The typical spectrum of the detected chemical elements and their isotopes in the AU1500 iodine air filter, which was exposed to the bremsstrahlung gamma quantum irradiation, produced by the accelerating electrons in the tantalum target, are obtained. The spatial distributions of the detected chemical element 127I and some other chemical elements and their isotopes in the layer of absorber, which was made of the cylindrical coal granule...

  8. Sobre os nomes dos elementos químicos, inclusive dos transférmios About the names of the chemical elements, including the transfermium elements

    OpenAIRE

    Rocha-Filho, Romeu C.; Aécio Pereira Chagas

    1999-01-01

    The names of the chemical elements in Brazilian portuguese are presented, including a discussion of corresponding Brazilian nomenclature rules and translation of some parts of the pertinent IUPAC rules. The rules for naming groups of elements in the periodic table, as well as those for the symbolic indication of atomic number, mass number and electric charge of atoms, are also presented.

  9. Gamification: using elements of video games to improve engagement in an undergraduate physics class

    Science.gov (United States)

    Rose, J. A.; O’Meara, J. M.; Gerhardt, T. C.; Williams, M.

    2016-09-01

    Gamification has been extensively implemented and studied in corporate settings and has proven to be more effective than traditional employee-training programs, however, few classroom studies of gamification have been reported in the literature. Our study explored the potential of gamified on-line undergraduate physics content as a mechanism to enhance student learning and motivation. Specifically, the main objective of this work was to determine whether extrinsic motivation indicators commonly used in video games could increase student engagement with course content outside of the classroom. Life Science students taking an introductory physics course were provided access to gamified multiple choice quizzes as part of their course assessment. The quizzes incorporated common gaming elements such as points, streaks, leaderboards and achievements, as well as some gamified graphical enhancements and feedback. Student attitudes and performance among those using the gamified quizzes were examined and compared to non-gamified control groups within the same course. Student engagement was quantified through examining student participation above and beyond the minimum course requirements. The results showed that gaming techniques are significantly correlated with increased engagement with course material outside of the classroom. These results may assist instructors in engaging and motivating students outside the classroom through carefully designed online and distance-delivered undergraduate physics content. Furthermore, the gaming elements incorporated in this study were not specifically tied to the physics content and can be easily translated to any educational setting.

  10. Micro Chemical (Elemental) Analysis of Leucas aspera (Willd) Link Employing SEM-EDAX

    OpenAIRE

    Sunkara Yashvanth; Satla Shobha Rani; S. S. Madhavendra

    2013-01-01

    The plant, Leucas aspera (Willd) Link is well known for its varied medicinal uses. Present study deals with its micro chemical (elemental) characterization using Energy Dispersive X-ray Analysis (EDAX) detector fitted to Scanning Electron Microscope. The plant has very interesting morphology. Crystals of varied shape and inclusions/exudates were noticed within and on the leaf & stem surfaces. Various plant parts analysed were, stem surface, stem sections, stem inclusions, blebs on stem hairs,...

  11. Assessing the Amount of Chemical Elements in Biodegradable Agricultural Wastes and ASH

    Directory of Open Access Journals (Sweden)

    Rasa Kvasauskienė

    2011-02-01

    Full Text Available Biodegradable agricultural wastes such as manure, has long been used as an organic fertilizer that improves soil structure, enriches the soil with micro-organisms and micro-elements necessary for plants and promotes humus formation. Manure can also be successfully used as a renewable energy source directly combusting and extracting energy. The carried out investigation showed that the incineration of manure remaining in ashes could also be used as a fertilizer. Waste combustion reduces its volume to 80–90%. Also, the investigation revealed that the amount of chemical elements (Na, Mg, Si, P, K, Ca, Ti, Mn, Fe decreased after combustion. However, the concentration of these elements in ashes is higher than that in raw manure. Article in Lithuanian

  12. Discrete formulation of mixed finite element methods for vapor deposition chemical reaction equations

    Institute of Scientific and Technical Information of China (English)

    LUO Zhen-dong; ZHOU Yan-jie; ZHU Jiang

    2007-01-01

    The vapor deposition chemical reaction processes, which are of extremely extensive applications, can be classified as a mathematical modes by the following governing nonlinear partial differential equations containing velocity vector,temperature field,pressure field,and gas mass field.The mixed finite element(MFE)method is employed to study the system of equations for the vapor deposition chemical reaction processes.The semidiscrete and fully discrete MFE formulations are derived.And the existence and convergence(error estimate)of the semidiscrete and fully discrete MFE solutions are deposition chemical reaction processes,the numerical solutions of the velocity vector,the temperature field,the pressure field,and the gas mass field can be found out simultaneonsly.Thus,these researches are not only of important theoretical means,but also of extremely extensive applied vistas.

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

    Science.gov (United States)

    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

  14. Distribution of cesium 137 and other chemical elements on the physical chemical barriers of a boundary zone of the Belarus Poles'e marsh

    International Nuclear Information System (INIS)

    An effect of the physical chemical barriers on distribution of cesium-137 and other chemical elements has been considered on the example of landscape-geochemical profile 'White Marsh' formed under conditions typical of Poles'e landscape-geochemical characteristics of the profile is presented. (authors). 2 figs., 1 tab., 7 refs

  15. B-cell-specific enhancer activity of conserved upstream elements of the class II major histocompatibility complex DQB gene

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, M.; Strominger, J.L.

    1988-09-01

    A 95-base-pair immediate upstream sequence of the human class II major histocompatibility complex DQB gene containing the conserved X and Y elements showed enhancer activity in a transient expression assay. An enhancer test plasmid harboring the bacterial chloramphenicol acetyltransferase gene under the control of a truncated simian virus 40 enhancerless early promoter was employed. The DQB sequence inserted into this plasmid was active as an enhancer in Raji cells (human Burkitt lymphoma cells) but not active in Jurkat cells (human T-cell leukemia cells) or in HeLa cells (human cervical carcinoma cells). This cell-type specificity suggests that this enhancer activity may be involved in the tissue specificity of the DQB gene that is normally expressed only in mature B cells, macrophages, and thymic epithelial cells. Deletion analysis showed that both X and Y box sequences are essential for the full activity of the enhancer sequence and that these two sequences may function in a cooperative manner as cis-acting elements. Further deletions were used to define the 5' border of the X element. These results suggest that previously characterized protein factors that bind to X and Y include transcription factors involved in the cell-type specificity of this enhancer activity.

  16. Sequential leaching behaviour of some elements during chemical treatment of ceramic censorship from coal fly ash

    International Nuclear Information System (INIS)

    The extractable contents of Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn were determined using a six-stage sequential leaching procedure to isolate: (1) water-soluble; (2) slightly changed organic matter; (3) carbonate; (4) Fe-Mn oxides; (5) glass and silicates; and (6) char fractions; of ceramic cenospheres (CCs) recovered from coal fly ash (FA). The leaching behaviour and modes of occurrence of the above-listed elements in CCs are discussed. The results show that this improved sequential leaching procedure applied on well characterized chemically and mineralogically CCs is promising and could be successfully used. (authors)

  17. Assessing the binding affinity of a selected class of DPP4 inhibitors using chemical descriptor-based multiple linear regression

    OpenAIRE

    Jose Isagani Janairo; Gerardo Janairo; Frumencio Co; Derrick Ethelbhert Yu

    2011-01-01

    The activity of a selected class of DPP4 inhibitors was preliminarily assessed using chemical descriptors derived AM1 optimized geometries. Using multiple linear regression model, it was found that ?E0, LUMO energy, area, molecular weight and ?H0 are the significant descriptors that can adequately assess the binding affinity of the compounds. The derived multiple linear regression (MLR) model was validated using rigorous statistical analysis. The preliminary model suggests t...

  18. Automatic Recognition of Element Classes and Boundaries in the Birdsong with Variable Sequences.

    Science.gov (United States)

    Koumura, Takuya; Okanoya, Kazuo

    2016-01-01

    Researches on sequential vocalization often require analysis of vocalizations in long continuous sounds. In such studies as developmental ones or studies across generations in which days or months of vocalizations must be analyzed, methods for automatic recognition would be strongly desired. Although methods for automatic speech recognition for application purposes have been intensively studied, blindly applying them for biological purposes may not be an optimal solution. This is because, unlike human speech recognition, analysis of sequential vocalizations often requires accurate extraction of timing information. In the present study we propose automated systems suitable for recognizing birdsong, one of the most intensively investigated sequential vocalizations, focusing on the three properties of the birdsong. First, a song is a sequence of vocal elements, called notes, which can be grouped into categories. Second, temporal structure of birdsong is precisely controlled, meaning that temporal information is important in song analysis. Finally, notes are produced according to certain probabilistic rules, which may facilitate the accurate song recognition. We divided the procedure of song recognition into three sub-steps: local classification, boundary detection, and global sequencing, each of which corresponds to each of the three properties of birdsong. We compared the performances of several different ways to arrange these three steps. As results, we demonstrated a hybrid model of a deep convolutional neural network and a hidden Markov model was effective. We propose suitable arrangements of methods according to whether accurate boundary detection is needed. Also we designed the new measure to jointly evaluate the accuracy of note classification and boundary detection. Our methods should be applicable, with small modification and tuning, to the songs in other species that hold the three properties of the sequential vocalization. PMID:27442240

  19. Distribution of some chemical elements between dissolved and particulate phases in the ocean

    International Nuclear Information System (INIS)

    The long-range goal of our research is to understand the processes that control the distribution and fate of chemical elements in the ocean, with emphasis on the rates at which the governing processes operate. Such an understanding is essential in predicting the fate of substances such as heavy metals and radionuclides that are released to the environment as a consequence of energy-producing activities. In pursuit of this goal we have, during the present contract period, devoted all of our effort to participation in the Shelf-Edge Exchange Processes (SEEP) program. Initial results from SEEP-1 are consistent with our hypothesis of enhanced scavenging of reactive chemical substances in upper slope sediments. During the next year we will complete our analytical work for SEEP-1 and carry out quantitative interpretations of our data with mathematical models to assess the importance of boundary uptake in this region of the continental margin. 8 references, 5 figures, 1 table

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

    Science.gov (United States)

    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 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.

  1. Chemical analysis of CH stars - II: atmospheric parameters and elemental abundances

    CERN Document Server

    Karinkuzhi, Drisya

    2014-01-01

    We present detailed chemical analyses for a sample of twelve stars selected from the CH star catalogue of Bartkevicius (1996). The sample includes two confirmed binaries, four objects that are known to show radial velocity variations and the rest with no information on the binary status. A primary objective is to examine if all these objects exhibit chemical abundances characteristics of CH stars, based on detailed chemical composition study using high resolution spectra. We have used high resolution (R ~ 42000) spectra from the ELODIE archive. These spectra cover 3900 to 6800 Angstrom in the wavelength range. We have estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g, and metallicity [Fe/H] from LTE analysis using model atmospheres. Estimated temperatures of these objects cover a wide range from 4200 K to 6640 K, the surface gravity from 0.6 to 4.3 and metallicity from -0.13 to -1.5. We report updates on elemental abundances for several heavy elements, Sr,...

  2. Statistic analysis of grouping in evaluation of the behavior of stable chemical elements and physical-chemical parameters in effluent from uranium mining

    International Nuclear Information System (INIS)

    The Ore Treatment Unit (UTM) is a uranium mine off. The statistical analysis of clustering was used to evaluate the behavior of stable chemical elements and physico-chemical variables in their effluents. The use of cluster analysis proved effective in the evaluation, allowing to identify groups of chemical elements in physico-chemical variables and group analyzes (element and variables ). As a result, we can say, based on the analysis of the data, a strong link between Ca and Mg and between Al and TR2O3 (rare earth oxides) in the UTM effluents. The SO4 was also identified as strongly linked to total solids and dissolved and these linked to electrical conductivity. Other associations existed, but were not as strongly linked. Additional collections for seasonal evaluation are required so that assessments can be confirmed. Additional statistics analysis (ordination techniques) should be used to help identify the origins of the groups identified in this analysis. (author)

  3. Assessment of some chemical element contents in Traganum nudatum Del shrub using instrumental neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    Bouzid Nedjimi; Brahim Beladel

    2015-01-01

    Instrumental neutron activation analysis (INAA) has been used to determine some chemical element contents (K, Ca, Na, Fe, Zn, Co, Eu, Sb, and Sc) in Traganum nudatum Del (Chenopodiaceae family) consumed in North African rangelands by sheep livestock. Samples were collected from the area of Djelfa in an arid steppe of Algeria. Results show that pasture halophyte had sufficient levels of K, Ca, Zn, and Co to meet the requirements of ruminants. However, it seems that this halophyte shrub had substantial amounts of Na, higher than the critical level established by the National Research Council (NRC). Eu, Sb, and Sc were within the safety baseline of all the assayed elements recommended by the NRC. The high Na content (∼10 g/kg) in this halophytic species requires elevated intake of water by livestock.

  4. Determination of rare earth elements in Taiwan monazite by chemical neutron activation analysis

    International Nuclear Information System (INIS)

    Taiwan monazite is a unique mineral obtained from the heavy sand found in the river floor of Tzuo-suei river and En-suei river. Both rivers are flowing parallel with separated narrow area into the sea at southwestern coast of Taiwan. The characteristic of monazite is that it contains considerable rare earth elements (REEs). REEs are considered very useful elements in the local industries and scientific researches such as ceramic, semiconductors, and glass optics. In this study, chemical neutron activation analysis (CNAA) was used to determine the contents of REEs in Taiwan monazite. A few milligram of monazite was digested in the microwave oven for 25 minutes with mixed acid (conc. HNO3 and HClO4). REEs were preconcentrated by hydrated magnesium oxide and CNAA was performed. (author)

  5. Adaptive Finite Element Method Assisted by Stochastic Simulation of Chemical Systems

    KAUST Repository

    Cotter, Simon L.

    2013-01-01

    Stochastic models of chemical systems are often analyzed by solving the corresponding Fokker-Planck equation, which is a drift-diffusion partial differential equation for the probability distribution function. Efficient numerical solution of the Fokker-Planck equation requires adaptive mesh refinements. In this paper, we present a mesh refinement approach which makes use of a stochastic simulation of the underlying chemical system. By observing the stochastic trajectory for a relatively short amount of time, the areas of the state space with nonnegligible probability density are identified. By refining the finite element mesh in these areas, and coarsening elsewhere, a suitable mesh is constructed and used for the computation of the stationary probability density. Numerical examples demonstrate that the presented method is competitive with existing a posteriori methods. © 2013 Society for Industrial and Applied Mathematics.

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

    International Nuclear Information System (INIS)

    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 298.150K and one atmosphere

  7. Numerical kinetic model including equilibrium and rate equations for chemical reactions of actinide elements

    International Nuclear Information System (INIS)

    Numerical simulation method was examined for chemical reactions of actinide elements U, Pu, Np, and Tc etc. in an aqueous nitric acid solution. It is known that the numerical calculation for the Purex process with chemical reactions and liquid flow becomes stiff, because time constant for the chemical reactions is two to three order of magnitude smaller due to the very fast reactions than that of mass transfer or of reaching distribution equilibrium. Recently in order to increase a time step Δt the partial equilibrium (P.E.) model, in which some very fast reactions are treated by the equilibrium law whereas other reactions are by the rate law, has been proposed. In the present study concentration change of the solutes in an aqueous solution with 30 chemical reactions, of which 4 are expressed by equilibrium equations, has been calculated. Description of the P.E. model and the comparison of the results and cpu time between the kinetic and the P.E. models are given. (author)

  8. Status of chemical elements in Atlantic Forest tree species near an industrial complex

    International Nuclear Information System (INIS)

    Environmental quality assessment studies have been conducted with tree species largely distributed in the Atlantic Forest. Leaf and soil samples were collected in the conservation unit Parque Estadual da Serra do Mar (PESM) nearby the industrial complex of Cubatao, Sao Paulo State, Brazil, and analyzed for chemical elements by instrumental neutron activation analysis. Results were compared to background values obtained in the Parque Estadual Carlos Botelho (PECB). The higher As, Fe, Hg and Zn mass fractions in the tree leaves of PESM indicated anthropogenic influence on this conservation unit. (author)

  9. Determination of chemical elements in Eucalyptus grandis, manured with Ballad's, by neutrons activation analysis

    International Nuclear Information System (INIS)

    The biosolid is a mud resulting from the biological treatment of wasted liquids. It is considered as a profitable alternative and important to minimize the environmental impact generated by the sewage thrown in to sanitary lands, in forest cultures like the Eucalyptus grandis. The objective of this work was to detect which chemical elements are present in Eucalyptus grandis samples, fertilized with different quantities of biosolid. The eucalyptuses of Estacao Experimental de Ciencias Florestais of Itatinga were planted in March of 1998 and collected with five years old. The used biosolid was produced by Station of Treatment of Sewer of Barueri - SP, classified as kind B. For the determination of the presence and quantity of chemical elements in the eucalyptus samples, an analysis technique by neutronic activation (NAA) was used followed by gamma rays spectroscopy. The samples were irradiated in the Nuclear Reactor IEA-R1 of IPEN-SP, followed by the measure of induced gamma rays activity, using a Detector HPGe. The presence, mainly of Br, Mn, Na and K, was detected in all analyzed samples. (author)

  10. Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances

    CERN Document Server

    Karinkuzhi, Drisya

    2014-01-01

    Results from high-resolution spectral analyses of a selected sample of CH stars are presented. Detailed chemical composition studies of these objects, which could reveal abundance patterns that in turn provide information regarding nucleosynthesis and evolutionary status, are scarce in the literature. We conducted detailed chemical composition studies for these objects based on high resolution (R ~ 42000) spectra. The spectra were taken from the ELODIE archive and cover the wavelength range from 3900 to 6800 A, in the wavelength range. We estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g, and metallicity [Fe/H] from Local thermodynamic equilibrium analyses using model atmospheres. Estimated temperatures of these objects cover a wide range from 4550 K to 6030 K, the surface gravity from 1.8 to 3.8 and metallicity from -0.18 to -1.4. We report updates on elemental abundances for several heavy elements and present estimates of abundance ratios of Sr, Y, Zr, B...

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

    Science.gov (United States)

    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

  12. Clustering of samples and elements based on multi-variable chemical data

    International Nuclear Information System (INIS)

    Clustering and classification are defined in the context of multivariable chemical analysis data. Classical multi-variate techniques, commonly used to interpret such data, are shown to be based on probabilistic and geometrical principles which are not justified for analytical data, since in that case one assumes or expects a system of more or less systematically related objects (samples) as defined by measurements on more or less systematically interdependent variables (elements). For the specific analytical problem of data set concerning a large number of trace elements determined in a large number of samples, a deterministic cluster analysis can be used to develop the underlying classification structure. Three main steps can be distinguished: diagnostic evaluation and preprocessing of the raw input data; computation of a symmetric matrix with pairwise standardized dissimilarity values between all possible pairs of samples and/or elements; and ultrametric clustering strategy to produce the final classification as a dendrogram. The software packages designed to perform these tasks are discussed and final results are given. Conclusions are formulated concerning the dangers of using multivariate, clustering and classification software packages as a black-box

  13. A new comprehensive set of elemental abundances in DLAs - II. Data analysis and chemical variation studies

    CERN Document Server

    Dessauges-Zavadsky, M; D'Odorico, S; Calura, F; Matteucci, F

    2005-01-01

    We present new elemental abundance studies of seven damped Lyman-alpha systems (DLAs). Together with the four DLAs analyzed in Dessauges-Zavadsky et al. (2004), we have a sample of eleven DLA galaxies with uniquely comprehensive and homogeneous abundance measurements. These observations allow one to study the abundance patterns of 22 elements and the chemical variations in the interstellar medium of galaxies outside the Local Group. Comparing the gas-phase abundance ratios of these high redshift galaxies, we found that they show low RMS dispersions, reaching only up 2-3 times the statistical errors for the majority of elements. This uniformity is remarkable given that the quasar sightlines cross gaseous regions with HI column densities spanning over one order of magnitude and metallicities ranging from 1/55 to 1/5 solar. The gas-phase abundance patterns of interstellar medium clouds within the DLA galaxies detected along the velocity profiles show, on the other hand, a high dispersion in several abundance rat...

  14. Post-buckled precompressed (PBP) elements: a new class of flight control actuators enhancing high-speed autonomous VTOL MAVs

    Science.gov (United States)

    Barrett, Ronald; McMurtry, Ross; Vos, Roelof; Tiso, Paolo; Breuker, Roeland D.

    2005-05-01

    This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements. These actuators are designed to produce significantly higher deflection and force levels than conventional piezoelectric actuator elements. Classical laminate plate theory (CLPT) models are shown to work very well in capturing the behavior of the free, unloaded elements. A new high transverse deflection model which employs nonlinear structural relations is shown to successfully predict the performance of the PBP actuators as they are exposed to higher and higher levels of axial force, which induces post buckling deflections. A proof-of-concept empennage assembly and actuator were fabricated using the principles of PBP actuation. A single grid-fin flight control effector was driven by a 3.5" (88.9mm) long piezoceramic bimorph PBP actuator. By using the PBP configuration, deflections were controllably magnified 4.5 times with excellent correlation between theory and experiment. Quasi-static bench testing showed deflection levels in excess of +/-6° at rates exceeding 15 Hz. The new solid state PBP actuator was shown to reduce the part count with respect to conventional servoactuators by an order of magnitude. Power consumption dropped from 24W to 100mW, weight was cut from 108g to 14g, slop went from 1.6° to 0.02° and current draw went from 5A to 1.4mA. The result was that the XQ-138 subscale UAV family experienced nearly a 4% reduction in operating empty weight via the switch from conventional to PBP actuators while in every other measure, gross performance was significantly enhanced.

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

    Science.gov (United States)

    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

  16. RADIOACTIVE CHEMICAL ELEMENTS IN THE ATOMIC TABLE

    International Nuclear Information System (INIS)

    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

  17. Deposition and mobility of chemical elements in forest and wetland environments

    International Nuclear Information System (INIS)

    A preliminary study has been initiated to observe organic-rich natural system such as forest litter, bogs, wetlands, marshlands, and rivers to evaluate the role organic matter plays in retaining chemical elements from fallout. We have found that 210Pb can be used to date the layers of certain types of wetlands over the past 150 years. The dating method also provides quantitative information on the rate of aerobic oxidation of the upper layers from the change in organic carbon. Several sites have shown that during the first 40 years, one-half of the initially deposited litter decomposes; after this time the rate of decomposition is much slower. The 137Cs has limited mobility after deposition; infiltration penetrates ≤ 20cm. The 137Cs is much more mobile in the organic-rich marshlands than in the clay-silt rich lake sediments. 239,240Pu is also mobilized, possibly as organic complexes. (author)

  18. Contents of chemical elements in stomach during prenatal development: different age-dependent dynamical changes and their significance

    Institute of Scientific and Technical Information of China (English)

    Shao-Fan Hou; Hai-Rong Li; Li-Zhen Wang; De-Zhu Li; Lin-Sheng Yang; Chong-Zheng Li

    2003-01-01

    AIM: To observe dynamic of different chemical elements in stomach tissue during fetal development.METHODS: To determine contents of the 21 chemical elements in each stomach samples from fetus aging four to ten months. The content values were compared to those from adult tissue samples, and the values for each month group were also analyzed for dynamic changes.RESULTS: Three representations were found regarding the relationship between contents of the elements and ages of the fetus, including the positive correlative (K), reversely correlative (Na, Ca, P, Al, Cu, Zn, Fe, Mn, Cr, Sr, Li, Cd, Ba,Se ) and irrelevant groups (Mg, Co, Ni, V, Pb, Ti).CONCLUSION: The chemical elements' contents in stomach tissues were found to change dynamically with the stomach weights. The age-dependent representations for different chemical elements during the prenatal development may be of some significance for assessing development of fetal stomach and some chemical elements. The data may be helpful for the nutritional balance of fetus and mothers during prenatal development and even the perinatal stages.

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

    International Nuclear Information System (INIS)

    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 hich 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 ack 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

  20. Some contradictions in contemporary assessment acrobatic elements used in the compositions of category "B-Class" in acrobatic rock'n'roll

    Directory of Open Access Journals (Sweden)

    Larisa Lutsenko

    2015-04-01

    Full Text Available Purpose: determine the impact of an innovative approach to improve the special physical and technical training of qualified athletes in acrobatic rock'n'roll. Material and Methods: theoretical analysis and synthesis of the literature, the competition rules, policy papers and documents catalog acrobatic elements "in class". The basic material for analysis was the changes to the 2014 WRRC, judging changes in their sport. Results: studied the catalog acrobatic elements "B-Class" (version 2 WRRC from 14.09.2014, reviewed and analyzed the results of stronger pairs category "B-class" in acrobatic rock'n'roll (World Cup, Russia, Sochi, Russia. The analysis of the requirements of execution of acrobatic elements. Conclusions: these findings demonstrate the need for an innovative approach to improve the special physical and technical training athletes acrobatic rock and roll category "B-Сlass". The difficulty level of acrobatic elements in acrobatic rock 'n' roll should be differential with respect to each of the age groups in their strict sequence the category "juniors" – "in-class" and "M-class".

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

    Science.gov (United States)

    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.

  2. Physical--chemical studies of transuranium elements. Progress report, April 1, 1976--March 31, 1977

    International Nuclear Information System (INIS)

    Major advances in our continuing program to determine, interpret, and correlate the basic chemical and physical properties of the transuranium elements are summarized for the period April 1, 1976, through March 31, 1977. Implementation of data reduction programs and acquisition of a CRT time-sharing graphics terminal/stand-alone computer have advanced significantly the handling capabilities of single-beam spectral data obtained by our microscope spectrophotometer. EsCl3, EsBr3, and EsI3 have been well characterized spectroscopically, and limited X-ray diffraction data have been obtained from EsBr3 and EsI3. The reduction of mixed Es-lanthanide trihalides has produced what might be Es(II). Dimorphism in BkCl3, CfCl3, and BkBr3 has been studied spectrophotometrically and the results confirmed by X-ray analysis. Our solution microcalorimeter was improved by reducing the system-generated electrical noise and developing a novel sample container. The operating sensitivity was determined to be within the desired 0.1 percent precision requirement. The necessary hardware was obtained and software development was initiated for the capability to acquire, store, and analyze the heat of solution data automatically. A very sensitive apparatus (SQUID) for the determination of magnetic susceptibility has been constructed and is being evaluated. Our device should greatly facilitate the study of microgram-sized samples of transuranium elements and compounds

  3. A chemical screen identifies class A G-protein coupled receptors as regulators of cilia

    OpenAIRE

    Avasthi, Prachee; Marley, Aaron; Lin, Henry; Gregori-Puigjane, Elisabet; Shoichet, Brian K.; von Zastrow, Mark; Marshall, Wallace F.

    2012-01-01

    Normal cilia length and motility are critical for proper cellular function. Prior studies of the regulation of ciliary structure and length have primarily focused on the intraflagellar transport machinery and motor proteins required for ciliary assembly and disassembly. However, several mutants with abnormal length flagella highlight the importance of signaling proteins as well. In this study, an unbiased chemical screen was performed to uncover signaling pathways that are critical for ciliog...

  4. Influence of relativistic effect on chemical properties of element 104; Wplyw efektu relatywistycznego na wlasnosci chemiczne pierwiastka 104

    Energy Technology Data Exchange (ETDEWEB)

    Bilewicz, A.

    1997-12-31

    The influence of relativistic effect upon chemical properties of element 104 is discussed. An original method of measurements of adsorption on the surface of thin film of cobalt ferrocyanate was developed and applied for the studies of 104{sup 4+} hydrolysis. Results of this experiments indicate that in the Group 4 tendency to hydrolysis decreases in the order 104{sup 4+}>Zr{sup 4+}>Hf{sup 4+}. The results were explained on the basis of relativistic effect. Unexpected chemical properties of element 104 in aqueous solutions indicate, that due to relativistic effect element 104 differs distinctly from its congeners - Zr and Hf. In contrary it becomes similar to the lightest element in the Group, Ti, through atomic mass of latter is 213 unit less. (author). 119 refs, 22 figs, 7 tabs.

  5. Natural and anthropogenic sources of chemical elements in sediment profiles from the Admiralty Bay, Antarctica

    International Nuclear Information System (INIS)

    Full text: The Antarctic Continent and its surrounding Southern Ocean are the least known regions of the world, mainly due to the most unfavorable climatic conditions, in which sampling for environmental studies are quite difficult to be carried out. Admiralty Bay on the King George Island (Antarctica) hosts three research stations, Arctowski, Ferraz and Macchu Picchu, which are operate by Poland, Brazil and Peru, respectively. Therefore, human activities in this region require the use of fossil fuel as an energy source, which is also considered the main source of pollutants in the area. This work investigated the natural and anthropogenic inputs of chemical elements in sediment samples collected close to Ferraz Station, during the 25th Brazilian Antarctica Expedition in the 2006/2007 austral summer. Total concentrations of As, Zn and Sc were determined in sediment profiles by using the Instrumental Neutron Activation Analysis (INAA). The analytical technique employed to determine the major elements such as Fe, Al, Ca, Mn and Ti was X-ray fluorescence (XRF) spectroscopy. For estimating the sedimentation rate, High Resolution Gamma Ray Spectrometry was applied to determine 137Cs, after 30 days, to achieve secular equilibrium. According to the enrichment factor and the geochronology analysis, the most relevant enrichment was observed for As in the sediment samples, suggesting the increasing of its content due to the Brazilian activities in the Admiralty Bay. Despite some evidences of anthropogenic contribution, the study indicated low level of environmental risk for this region. (author)

  6. Automatic recognition of element classes and boundaries in the birdsong with variable sequences

    OpenAIRE

    Koumura, Takuya; Okanoya, Kazuo

    2016-01-01

    Researches on sequential vocalization often require analysis of vocalizations in long continuous sounds. In such studies as developmental ones or studies across generations in which days or months of vocalizations must be analyzed, methods for automatic recognition would be strongly desired. Although methods for automatic speech recognition for application purposes have been intensively studied, blindly applying them for biological purposes may not be an optimal solution. This is because, unl...

  7. Chemical response pattern of different classes of C-nociceptors to pruritogens and algogens.

    Science.gov (United States)

    Schmelz, M; Schmidt, R; Weidner, C; Hilliges, Marita; Torebjork, H E; Handwerker, H O

    2003-05-01

    Vasoneuroactive substances were applied through intradermal microdialysis membranes and characterized as itch- or pain-inducing in psychophysical experiments. Histamine always provoked itching and rarely pain, capsaicin always pain but never itching. Prostaglandin E(2) (PGE(2)) led preferentially to moderate itching. Serotonin, acetylcholine, and bradykinin induced pain more often than itching. Subsequently the same substances were used in microneurography experiments to characterize the sensitivity profile of human cutaneous C-nociceptors. The responses of 89 mechanoresponsive (CMH, polymodal nociceptors), 52 mechanoinsensitive, histamine-negative (CMi(His-)), and 24 mechanoinsensitive, histamine-positive (CMi(His+)) units were compared. CMi(His+) units were most responsive to histamine and to PGE(2) and less to serotonin, ACh, bradykinin, and capsaicin. CMH units (polymodal nociceptors) and CMi(His-) units showed significantly weaker responses to histamine, PGE(2), and acetylcholine. Capsaicin and bradykinin responses were not significantly different in the two classes of mechano-insensitive units. We conclude that CMi(His+) units are "selective," but not "specific" for pruritogenic substances and that the pruritic potency of a mediator increases with its ability to activate CMi(His+) units but decreases with activation of CMH and CMi(His-) units. PMID:12611975

  8. A differential chemical element analysis of the metal poor Globular Cluster NGC 6397

    CERN Document Server

    Koch, Andreas

    2011-01-01

    We present chemical abundances in three red giants and two turn-off stars in the metal poor Galactic globular cluster (GC) NGC 6397 based on spectroscopy obtained with the MIKE 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 ~0.1 dex, with opposite sign for the 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 ...

  9. Chemical Elements in Mulch and Litterfall of Beech Ecosystems and Their Total Turnover

    Directory of Open Access Journals (Sweden)

    Mariyana I. Lyubenovа

    2011-07-01

    Full Text Available The beech communities on the territory of Bulgaria had been objects of regional, local as well as large scale national investigations aiming their classification, determination of their ecological characteristics, conservation status, habitats etc. They are included as objects of the intensive monitoring of forest ecosystems in Bulgaria also. The investigations of chemical content of the litter – fall in these forests were conducted until now. The novelty of the present research is investigation of these elements in the mulch and the ratio between the established quantities calculation. The main goal is the biological turnover special features characterization of the investigated elements which give us a chance to define the investigated ecosystems state and functioning. The indexes as litter – mulch and acropetal coefficients were used for this aim. The content of macroelements as N, Ca and K and microelements as Pb, Zn, Mn and Fe in soils, mulch and in different litter fall fractions have been calculated. The investigation was carried out on three sample plots. During the investigation was established that the soils are characterized with acid reaction, high content of Fe, N and Mn and low content of Ca and K. The concentration of Zn and Pb are high also. The calculated average store of investigated elements in litter – fall is 81.312 kg.ha1 and in the mulch 314 kg.ha1. According to the acropetal coefficient N is accumulated mainly in the acorns, K – in the annual phytomass fractions and Ca – in the perennial fractions. The leaves and the acorns fraction accumulate Mn, and cupolas Fe. The litter – mulch coefficient vary from 1,6 (Mn to 4,2 (Pb. The tendencies of Zn and Ca turnovers acceleration are discovered, while the turnover of more investigated elements is inhibited. The litter – mulch coefficient for Zn and Ca is 0,8 and 1,4 accordingly, i.е. corresponding to the intensive type of turnovers which is not typical for the

  10. Burst and Principal Components Analyses of MEA Data Separates Chemicals by Class

    Science.gov (United States)

    Microelectrode arrays (MEAs) detect drug and chemical induced changes in action potential "spikes" in neuronal networks and can be used to screen chemicals for neurotoxicity. Analytical "fingerprinting," using Principal Components Analysis (PCA) on spike trains recorded from prim...

  11. A search for losses of chemical elements during freeze-drying of biological materials

    International Nuclear Information System (INIS)

    Possible losses of seven chemical elements were investigated in biological tissues during freeze-drying in vacuum. Thyroid glands were taken during post-mortem examination of 23 people died of different diseases. Instrumental neutron activation analysis (INAA) was used to estimate contents of Br, Ca, Cl, I, K, Mg, and Na. The nuclear reactor vertical channel with flux density of 1.2 x 1013 n x cm-2 x s-1 was used for neutron irradiation. The analysis was carried out using short-lived radionuclides induced in samples after neutron irradiation. Then thyroids were freeze-dried at below 0 deg C in vacuum up to the constant mass (lyophilisation) and then homogenized. Samples of lyophilised and homogenized tissues were again studied by INAA. The lack of difference between the results of the analysis before and after lyophilisation is an evidence of no loss of Br, Ca, Cl, I, K, Mg, and Na during freeze-drying of biotissues in vacuum. (author)

  12. Glossary of class names of polymers based on chemical structure and molecular architecture (IUPAC Recommendations 2009)

    Czech Academy of Sciences Publication Activity Database

    Baron, M.; Hellwich, K. H.; Hess, M.; Horie, K.; Jenkins, A.D.; Jones, R. G.; Kahovec, Jaroslav; Kratochvíl, Pavel; Metanomski, W. V.; Mormann, W.; Stepto, R. F. T.; Vohlídal, J.; Wilks, E. S.

    2009-01-01

    Roč. 81, č. 6 (2009), s. 1131-1183. ISSN 0033-4545 R&D Projects: GA MŠk(CZ) LA09028 Keywords : IUPAC Polymer Division * macromolecule architecture * polymer class names Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.289, year: 2009

  13. Separation of chemically similar elements such as trivalent actinides and lanthanides

    International Nuclear Information System (INIS)

    Separation of chemical elements has been during all times an interesting topic and references may be found from ∼ 3000 B.C., i.e. ion exchange for purification of drinking water. With increasing knowledge the separation methods have become more and more refined. There are many methods used for the separation processes, e.g. pyrometallurgy, chromatographic methods, ion exchange and solvent extraction. Of these the solvent extraction technique is widely used today due to its relative simplicity to scale up and use industrially. The solvent extraction processes have been successfully used during the last 100 years in various areas ranging from the mining industry to the reprocessing of spent nuclear fuel. In some cases the elements that are to be separated have quite different chemical properties and a relatively simple process can be used. In the case of separation of trivalent metal ions with similar properties such as trivalent actinides and lanthanides the problem is more difficult. The separation of actinides and lanthanides is an important question when considering future alternatives to take care of waste from reprocessing of spent nuclear fuel (in for instance a transmutation process). To decrease process losses to secondary waste streams it has been decided that only extracting agents containing carbon, hydrogen, oxygen and nitrogen are to be used, which further increases the difficulty level. Two examples of such ligands are 2,2': 6' ,2-terpyridine and 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine. It has been shown that using such ligands, good separation of actinides and lanthanides can be achieved. This is mainly because nitrogen binds more strongly to actinides than to lanthanides due to the more covalent nature of the bond. Often synergistic extraction is used, adding the reagent to e,g. a 2-bromodecanoic acid extraction system in order to increase the extraction and the separation efficiency. In addition it is also possible to separate different

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

    Directory of Open Access Journals (Sweden)

    F. P. Agterberg

    2012-01-01

    Full Text Available 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

  15. A new class of HIV-1 protease inhibitor: the crystallographic structure, inhibition and chemical synthesis of an aminimide peptide isostere.

    Science.gov (United States)

    Rutenber, E E; McPhee, F; Kaplan, A P; Gallion, S L; Hogan, J C; Craik, C S; Stroud, R M

    1996-09-01

    The essential role of HIV-1 protease (HIV-1 PR) in the viral life cycle makes it an attractive target for the development of substrate-based inhibitors that may find efficacy as anti-AIDS drugs. However, resistance has arisen to potent peptidomimetic drugs necessitating the further development of novel chemical backbones for diversity based chemistry focused on probing the active site for inhibitor interactions and binding modes that evade protease resistance. AQ148 is a potent inhibitor of HIV-1 PR and represents a new class of transition state analogues incorporating an aminimide peptide isostere. A 3-D crystallographic structure of AQ148, a tetrapeptide isostere, has been determined in complex with its target HIV-1 PR to a resolution of 2.5 A and used to evaluate the specific structural determinants of AQ148 potency and to correlate structure-activity relationships within the class of related compounds. AQ148 is a competitive inhibitor of HIV-1 PR with a Ki value of 137 nM. Twenty-nine derivatives have been synthesized and chemical modifications have been made at the P1, P2, P1', and P2' sites. The atomic resolution structure of AQ148 bound to HIV-1 PR reveals both an inhibitor binding mode that closely resembles that of other peptidomimetic inhibitors and specific protein/inhibitor interactions that correlate with structure-activity relationships. The structure provides the basis for the design, synthesis and evaluation of the next generation of hydroxyethyl aminimide inhibitors. The aminimide peptide isostere is a scaffold with favorable biological properties well suited to both the combinatorial methods of peptidomimesis and the rational design of potent and specific substrate-based analogues. PMID:8894111

  16. Fractional crystallization models for calculating distribution coefficients of chemical elements between magmas and their crystallization products

    International Nuclear Information System (INIS)

    Igneous rock successions can be investigated with respect to their genetic coherence or to the role in fractional crystallization during their generation, respectively, by evaluating element concentration correlations. It is shown that the existence of a linear relation between element concentrations or their logarithms is only a necessary, but not a sufficient condition for fractional crystallization as the dominating factor of graduating element concentrations. The comparison of the slope of such correlation lines with the slope calculated on the basis of the distribution coefficients evaluated by using Schuetze's 18O index reveals whether fractional crystallization is dominant in graduating element concentrations in igneous rocks. Several applications are given. (author)

  17. Plant absorption of trace elements in sludge amended soils and correlation with soil chemical speciation

    Energy Technology Data Exchange (ETDEWEB)

    Torri, Silvana, E-mail: torri@agro.uba.ar [Catedra de Fertilidad y Fertilizantes, Facultad de Agronomia, UBA, Avda San Martin 4453, Buenos Aires (C1417 DSE) (Argentina); Lavado, Raul [Catedra de Fertilidad y Fertilizantes, Facultad de Agronomia, UBA, Avda San Martin 4453, Buenos Aires (C1417 DSE) (Argentina)

    2009-07-30

    The aim of the present study was to investigate the relationship between Lolium perenne L. uptake of Cd, Cu, Pb, and Zn in sludge amended soils and soil availability of these elements assessed by soil sequential extraction. A greenhouse experiment was set with three representative soils of the Pampas Region, Argentina, amended with sewage sludge and sewage sludge enriched with its own incinerated ash. After the stabilization period of 60 days, half of the pots were sampled for soil analysis; the rest of the pots were sown with L. perenne and harvested 8, 12, 16 and 20 weeks after sowing, by cutting just above the soil surface. Cadmium and Pb concentrations in aerial tissues of L. perenne were below detection limits, in good agreement with the soil fractionation study. Copper and Zn concentration in the first harvest were significantly higher in the coarse textured soil compared to the fine textured soil, in contrast with soil chemical speciation. In the third harvest, there was a positive correlation between Cu and Zn concentration in aerial biomass and soil fractions usually considered of low availability. We conclude that the most available fractions obtained by soil sequential extraction did not provide the best indicator of Cu and Zn availability to L. perenne.

  18. Effect of Extension and Type of Composite-Restored Class II Cavities on Biomechanical Properties of Teeth: A Three Dimensional Finite Element Analysis

    OpenAIRE

    Azam Valian; Elham Moravej-Salehi; Allahyar Geramy; Elham Faramarzi

    2015-01-01

    Objectives: Controversy exists regarding cavity preparation for restoration of interproximal caries in posterior teeth in terms of preserving the tooth structure and suitable stress distribution. This study aimed to assess the effect of extension and type of class II cavities and the remaining tooth structure in maxillary premolars restored with composite resin on the biomechanical properties of teeth using finite element method (FEM). Materials and Methods: Using FEM, eight three-dimensional...

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

    Science.gov (United States)

    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…

  20. The role of colloidal matter in transfer of chemical elements in the boreal zone (European Russia)

    OpenAIRE

    Ilina, Svetlana

    2012-01-01

    The objective of this thesis was to study element speciation and migration in the boreal environments (Karelia and Central Russia). Specific goals were to i) characterize the molecular weight distribution of trace elements and organic matter (OM) in various types of natural waters, ii) reveal the TE colloidal forms dependence in the continuum soil solution - bog - stream - feeding and terminal lakes in the surface waters of boreal watersheds, and iii) quantify the dependence of stable and rad...

  1. Numerical simulation of isothermal chemical vapor infiltration process in fabrication of carbon-carbon composites by finite element method

    Institute of Scientific and Technical Information of China (English)

    李克智; 李贺军; 姜开宇

    2000-01-01

    The chemical vapor infiltration process in fabrication of carbon-carbon composites is highly inefficient and requires long processing time. These limitations add considerably to the cost of fabrication and restrict the application of this material. Efforts have been made to study the CVI process in fabrication of carbon-carbon composites by computer simulation and predict the process parameters, density, porosity, etc. According to the characteristics of CVI process, the basic principle of FEM and mass transport, the finite element model has been established. Incremental finite element equations and the elemental stiffness matrices have been derived for the first time. The finite element program developed by the authors has been used to simulate the ICVI process in fabrication of carbon-carbon composites. Computer color display of simulated results can express the densification and distributions of density and porosity in preform clearly. The influence of process parameters on the densification of prefo

  2. Polycationic ligands of different chemical classes stimulate DNA strand displacement between short oligonucleotides in a protein-free system.

    Science.gov (United States)

    Volodin, Alexander A; Bocharova, Tatiana N; Smirnova, Elena A

    2016-09-01

    The ability of polycationic ligands to stimulate DNA strand displacement between short oligonucleotides in a protein-free system is demonstrated. We show that two ligands, tetracationic aliphatic amine (spermine) and a dicationic intercalating drug (chloroquine), promote strand displacement in a concentration-dependent manner. At low concentrations both ligands decelerate spontaneous strand displacement because of their impact on the stability of the DNA duplex. At elevated concentrations they accelerate strand displacement via formation of intermediate structures containing three DNA strands. The rate of the last process does not correlate with the thermal dissociation rate of the entire DNA duplex. It indicates that, possibly, the action of these agents cannot be explained by their influence on the stability of the DNA duplex. In general, our results suggest that the ability to stimulate DNA strand displacement appears to be a common feature of polycations of different chemical and structural classes. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 633-641, 2016. PMID:27106951

  3. Comparison of chemical fertilizer and sewage sludge application on some nutrients’ bioavailability in three textural classes of a calcareous soil after harvesting spinach (Spinacia oleracea L.

    Directory of Open Access Journals (Sweden)

    H.R Boostani

    2012-12-01

    Full Text Available Sewage sludge (SS as a source of macro- and micro nutrients has been utilized in many countries for crop and vegetable production. To compare the influence of SS with chemical fertilizer on macro- and micro nutrients bioavailability in three textural classes of a calcareous soil after harvesting spinach (Spinacia oleracea L., a factorial experiment was carried out in a completely randomized design with two factors and three replications under glasshouse conditions. The first factor was SS levels (0, 10, 20, 40, and 80 mg per kg soil and the second factor was soil textural classes (sandy, sandy loam, and clay loam. A chemical fertilizer treatment was used for comparison with the applied SS treatments. Results indicated that total nitrogen (N and available phosphorus (P was significantly higher in SS amended soils compared to fertilizer treatment. Effect of increasing soil potassium (K due to addition of SS was less than P and N, which is probably due to low content of K in SS. Soil DTPA extractable iron, zinc, copper, and manganese were significantly increased in SS treatments in all soil textures and were higher than fertilizer treatment. Based on nutrients’ bioavailability in soil after harvesting spinach, especially at high rates of SS, addition of most nutrients is not necessary for the next crop. Concentration of DTPA extractable cadmium (Cd and lead (Pb was not detectable in all treatments. Therefore, because of low contents of Cd and Pb in the utilized SS, reaching to a toxic level of these elements in soil is unexpected. However, if high levels of SS are applied frequently, soil test is recommended for monitoring heavy metals concentration in amended soils. Prior to any SS recommendation, the results of this research need to be verified under field conditions.

  4. Attempts to chemically investigate element 112

    International Nuclear Information System (INIS)

    Two experiments aiming at the chemical investigation of element 112 produced in the heavy ion induced nuclear fusion reaction of 48Ca with 238U were performed at the Gesellschaft fuer 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 C and of Rn at about -180 C. Reports from the Flerov Laboratory for Nuclear Reactions (FLNR), Dubna, Russia claim production of a 5-min spontaneous fission (SF) activity assigned to 283112 for the 238U(48Ca,3n) 283112 reaction. Hence, experiment 1 was designed to detect spontaneously fissioning (SF) isotopes of element 112 with half-lives (t1/2) 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 2 was lower than expected for a SF-decay of 283112. Therefore, these events could not be unambiguously attributed to the decay of 283112. In contradiction with earlier publications newer reports from FLNR Dubna claim that 283112 decays by α-particle emission (Eα = 9.5 MeV) with t1/2 = 4 s followed by a SF-decay of 279Ds (t1/2 = 0.2 s). Therefore, experiment 2 was designed to be sensitive to both claimed decay properties of 283112. However, during this experiment neither short α-SF correlations nor SF co-incidences were detected. The conclusion is that 283112 was not unambiguously detected, neither in experiment 1 nor in experiment 2. (orig.)

  5. Chemical Elements at High and Low Redshifts

    CERN Document Server

    Pettini, M

    2006-01-01

    The past few years have seen a steady progress in the determination of element abundances at high redshifts, with new and more accurate measures of metallicities in star-forming galaxies, in QSO absorbers, and in the intergalactic medium. We have also become more aware of the limitations of the tools at our disposal in such endeavours. I summarise these recent developments and--in tune with the theme of this meeting--consider the clues which chemical abundance studies offer to the links between the high redshift galaxy populations and today's galaxies. The new data are `fleshing out' the overall picture of element abundances at redshifts z = 2 - 3 which has been gradually coming into focus over the last decade. In particular, we can now account for at least 40% of the metals produced by the global star formation activity in the universe from the Big Bang to z = 2.5, and we have strong indications of where the remainder are likely to be found.

  6. The Assessment of Comprehensive Vulnerability of Chemical Industrial Park Based on Entropy Method and Matter-element Extension Model

    Directory of Open Access Journals (Sweden)

    Yan Jingyi

    2016-01-01

    Full Text Available The paper focuses on studying connotative meaning, evaluation methods and models for chemical industry park based on in-depth analysis of relevant research results in China and abroad, it summarizes and states the feature of menacing vulnerability and structural vulnerability and submits detailed influence factors such as personnel vulnerability, infrastructural vulnerability, environmental vulnerability and the vulnerability of safety managerial defeat. Using vulnerability scoping diagram establishes 21 evaluation indexes and an index system for the vulnerability evaluation of chemical industrial park. The comprehensive weights are calculated with entropy method, combining matter-element extension model to make the quantitative evaluation, then apply to evaluate some chemical industrial park successfully. This method provides a new ideas and ways for enhancing overall safety of the chemical industrial park.

  7. Chemical study of intermediate-mass (IM) Class 0 protostars. CO depletion and N2H+ deuteration

    CERN Document Server

    Alonso-Albi, T; Crimier, N; Caselli, P; Ceccarelli, C; Johnstone, D; Planesas, P; Rizzo, J R; Wyrowski, F; Tafalla, M; Lefloch, B; Maret, S; Dominik, C

    2010-01-01

    We are carrying out a physical and chemical study of the protostellar envelopes in a representative sample of IM Class 0 protostars. In our first paper (Crimier et al. 2010), we determined the physical structure (Density-Temperature radial profiles) of the protostellar envelopes. Here, we study the CO depletion and N2H+ deuteration. We observed the millimeter lines of C18O, C17O, N2H+ and N2D+ toward the protostars using the IRAM 30m telescope. Based on these observations, we derived the C18O, N2H+ and N2D+ radial abundance profiles across their envelopes using a radiative transfer code. In addition, we modeled the chemistry of the protostellar envelopes. All the C18O 1-0 maps are well fit assuming that the C18O abundance decreases inwards within the protostellar envelope until the gas and dust reach the CO evaporation temperature, 20-25K, where the CO is released back to the gas phase. The N2H+ deuterium fractionation in Class 0 IMs is [N2D+]/[N2H+]=0.005-0.014, two orders of magnitude larger than the elemen...

  8. Study of the physico-chemical behavior of transuranian elements in radioactive waste repositories

    International Nuclear Information System (INIS)

    Transuranian chemistry is being studied in the geochemical context of the geological disposal of radioactive waste. The transuranians considered are plutonium, neptunium and americium. The first part, devoted to the chemistry of these elements in aqueous solutions, consists of a critical compilation of literature data with a view to resulting in producing the Eh-pH diagrams of transuranians in a complexing environment. The study of the retention by constituents of artificial clay barriers (bentonite and attapulgite) is the subject of the second part. The third part concerns the development of a measurement technique for transuranian elements at trace levels by the thermal lensing method

  9. Black poplar-tree (Populus nigra L.) bark as an alternative indicator of urban air pollution by chemical elements

    International Nuclear Information System (INIS)

    Capabilities of black poplar-tree (Populus nigra L.) bark as a biomonitor of atmospheric air pollution by chemical elements were tested against epiphytic lichens Xanthoria parietina (L.) and Physcia adscendens (Fr.). Concentrations of 40 macro and trace elements were determined using epicadmium and instrumental NAA. The data obtained were processed using non-parametric tests. A good correlation was found between concentrations of majority of elements in bark and lichens. On the accumulation capability bark turned out to be competitive with both lichens examined. The main inorganic components of black poplar-tree bark were revealed. A substrate influence on the concentrations of some elements in epiphytic lichens was established. An optimized procedure of bark pre-irradiation treatment was suggested. (author)

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

    Science.gov (United States)

    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.

  11. Computational and statistical analyses of amino acid usage and physico-chemical properties of the twelve late embryogenesis abundant protein classes.

    Directory of Open Access Journals (Sweden)

    Emmanuel Jaspard

    Full Text Available Late Embryogenesis Abundant Proteins (LEAPs are ubiquitous proteins expected to play major roles in desiccation tolerance. Little is known about their structure - function relationships because of the scarcity of 3-D structures for LEAPs. The previous building of LEAPdb, a database dedicated to LEAPs from plants and other organisms, led to the classification of 710 LEAPs into 12 non-overlapping classes with distinct properties. Using this resource, numerous physico-chemical properties of LEAPs and amino acid usage by LEAPs have been computed and statistically analyzed, revealing distinctive features for each class. This unprecedented analysis allowed a rigorous characterization of the 12 LEAP classes, which differed also in multiple structural and physico-chemical features. Although most LEAPs can be predicted as intrinsically disordered proteins, the analysis indicates that LEAP class 7 (PF03168 and probably LEAP class 11 (PF04927 are natively folded proteins. This study thus provides a detailed description of the structural properties of this protein family opening the path toward further LEAP structure - function analysis. Finally, since each LEAP class can be clearly characterized by a unique set of physico-chemical properties, this will allow development of software to predict proteins as LEAPs.

  12. Assessment of the sources of chemical elements in sediment from Arak Mighan Lake

    Institute of Scientific and Technical Information of China (English)

    Feridon GHADIMI

    2014-01-01

    Five sediment zones (20 samples) were collected in Mighan Lake, near Arak city in Markazi province, and were analyzed to reveal element sources and assess the quality of metal contamination. Both anthropogenic and natural origins were identified by correlation, factor, and cluster analyse. According to the enrichment factors (EF) of trace metals (Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, Zr, and Zn), three groups were identified. Enriched trace elements included: Ni, Zn, and Sr. Comparisons with contamination degree and benchmark sediment quality criteria and guidelines showed that Mighan Lake has potential for adverse effects on aquatic biota because of Ni, Zn, and Cr.

  13. On the Necessity of Using Element No.155 in the Chemical Physical Calculations: Again on the Upper Limit in the Periodic Table of Elements

    OpenAIRE

    Khazan A.

    2010-01-01

    It is shown how the properties of different elements of the Periodic System of Elements can be obtained using the properties of the theoretically predicted heaviest element No.155 (it draws the upper principal limit of the Table, behind which stable elements cannot exist). It is suggested how the properties of element No.155 can be used in the synthesis of superheavy elements. An analysis of nuclear reactions is also produced on the same basis.

  14. On the Necessity of Using Element No.155 in the Chemical Physical Calculations: Again on the Upper Limit in the Periodic Table of Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2010-10-01

    Full Text Available It is shown how the properties of different elements of the Periodic System of Elements can be obtained using the properties of the theoretically predicted heaviest element No.155 (it draws the upper principal limit of the Table, behind which stable elements cannot exist. It is suggested how the properties of element No.155 can be used in the synthesis of superheavy elements. An analysis of nuclear reactions is also produced on the same basis.

  15. Study on Model of Correlation Between Chemical Element Contents in Tree Rings and Soils near Tree Roots

    Institute of Scientific and Technical Information of China (English)

    KESHAN-ZHE; QIANJUN-LONG; 等

    1994-01-01

    The chemical element contents in tree rings are correlated with those in the soils near the tree roots,The results in the present study showed that the correlation between them could be described using the following logarithmic linear correlation model:lgC'(Z)=a(Z)+b(Z)lgC(Z).Therefor,by determining the chrono-sequence C(Z,t),where Z is the atomic number and t the year,of elemental contents in the annual growth rings of trees,we could get the chrono-sequence C'(Z,t) of elemental contents in the soil,thus inferring the dynaminc variations of relevant elemental contents in the soil.

  16. Chemical portioning and speciation of some trace elements in soil and street dust from Khartoum state, Sudan

    International Nuclear Information System (INIS)

    In this study, surface soil and street dust samples were collected from Khartoum State, from areas exposed to industrial and traffic emission and from areas expected to be free from elemental emission to serve as control. Samples were digested using wet digestion method to determine the total concentration of Na, K, Cr, Mn, Fe, Cu, Zn and Pb using Atomic Absorption spectrophotometer (Aas), X-Ray fluorescence and flame photometer. Also samples were chemically fractionated using chemical specification method, and the solutions analyzed using Aas to determine the chemical form of the elements. Quality assurance of the data was achieved through the analysis of certified reference material. The range of the total concentration for Na, K, Mn, Fe, Cu, Zn and Pb are 400-5175, 220-4690, 0.07-315.25, 20-250, 2050.8-46000, 0.5-2305, 4.5-280, 9.5-6200 mg/kg respectively. results obtained agree with expected emission profile as inferred from the emitting source locations. Distribution of elements from emitting source locations and control samples in different chemical fractions was carried out, and the findings reinforced by enrichment factors calculations as well by the results obtained by statistical multi-variate analysis methods such as principle compared with previous literature.(Author)

  17. Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

    Institute of Scientific and Technical Information of China (English)

    Jun Hwan Kim; Byoung Oon Lee; Chan Bock Lee; Seung Hyun Jee; Young Soo Yoon

    2012-01-01

    The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction (FCCI) behavior.Mischmetal (70Ce-30La) and Nd were prepared as rare earth elements.Diffusion couple testing was performed on the rare earth elements and cladding (9Cr2W steel) near the operation temperature of(sodium-cooled fast reactor) SFR fuel.The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated.Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law,describing the migration of the rare earth element.The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law.Rare earth materials could be used as a surrogate for high burnup metallic fuels,and the performance of the barrier material was demonstrated to be effective.

  18. Independent Emergence of Resistance to Seven Chemical Classes of Fungicides in Botrytis cinerea.

    Science.gov (United States)

    Fernández-Ortuño, Dolores; Grabke, Anja; Li, Xingpeng; Schnabel, Guido

    2015-04-01

    Gray mold, caused by the fungal pathogen Botrytis cinerea, is one of the most destructive diseases of small fruit crops and control is largely dependent on the application of fungicides. As part of a region-wide resistance-monitoring program that investigated 1,890 B. cinerea isolates from 189 fields in 10 states of the United States, we identified seven isolates (0.4%) from five locations in four different states with unprecedented resistance to all seven Fungicide Resistance Action Committee (FRAC) codes with single-site modes of action including FRAC 1, 2, 7, 9, 11, 12, and 17 registered in the United States for gray mold control. Resistance to thiophanate-methyl, iprodione, boscalid, pyraclostrobin, and fenhexamid was based on target gene mutations that conferred E198A and F200Y in β-tubulin, I365N/S in Bos1, H272R/Y in SdhB, G143A in Cytb, and T63I and F412S in Erg27. Isolates were grouped into MDR1 and MDR1h phenotypes based on sensitivity to fludioxonil and variations in transcription factor mrr1. MDR1h isolates had a previously described 3-bp deletion at position 497 in mrr1. Expression of ABC transporter atrB was increased in MDR1 isolates but highest in MDR1h isolates. None of the isolates with seven single resistances (SR) had identical nucleotide variations in target genes, indicating that they emerged independently. Multifungicide resistance phenotypes did not exhibit significant fitness penalties for the parameters used in this study, but MDR1h isolates produced more sclerotia at low temperatures and exhibited increased sensitivity to salt stress. In this study we show that current resistance management strategies have not been able to prevent the geographically independent development of resistance to all seven site-specific fungicides currently registered for gray mold control in the United States and document the presence of MDR1h in North America. PMID:25317841

  19. Physical-chemical studies of transuranium elements. Progress report, April 1, 1982-March 31, 1983

    International Nuclear Information System (INIS)

    Progress is reported on the following topics: electrochemical and spectroscopic studies of less-stable higher oxidation states of transuranium elements in complexing aqueous media; spectroscopic and electrochemical studies of selected lanthanides and actinides in molten dimethyl sulfone; spectroelectronchemical studies of the Ce(IV)/Ce(III) couple in aqueous carbonate solutions; characterization of actinide orthophosphates by Raman and absorption spectrophotometries and by x-ray diffraction; relativistic multiple scattering calculations on transuranium element compounds; Raman spectroscopic studies of natural minerals containing the uranyl ion; and solution calorimetry of californium metal

  20. Study of chemical element composition dependency of exposure buildup factors in concrete shielding

    International Nuclear Information System (INIS)

    Gamma ray exposure buildup factor mainly dependent on the composition of which it is made therefore the effect of elemental composition has been studied for concrete shielding. The buildup factors are derived by G-P fitting formula in the photon energy range 0.015-15 MeV up to penetration depth of 40 mfp. The exposure buildup factors of the concretes shielding shows sharp variation beyond 3 MeV photon energy for penetration depth above 10 mfp. (author)

  1. The periodic kingdom a journey into the land of the chemical elements

    CERN Document Server

    Atkins, P W

    2008-01-01

    The one hundred or so elements listed in the table make up everything in the universe, from microscopic organisms to distant planets. Just how does the periodic table help us make sense of the world around us? Using vivid imagery, ingenious analogies, and liberal doses of humor P. W. Atkins answers this question. He shows us that the Periodic Kingdom is a systematic place. Detailing the geography, history and governing institutions of this imaginary landscape, he demonstrates how physical similarities can point to deeper affinities, and how the location of an element can be used to predict its

  2. Chemical extraction methods for assessment of phytoavailable fractions of elements in soils

    International Nuclear Information System (INIS)

    This study develops extraction methods of phytoavailable fractions of elements in soil for precise estimation of soil-to-plant transfer of radionuclides released from nuclear facilities, such as a reprocessing plant in Rokkasho. The soil-to-plant transfer factor based on the total concentration in soil generally scattered in a few orders of magnitude. This large variance is most likely attributable to ignorance of phytoavailability of radionuclides in soil. The transfer factor based on phytoavailable fractions of the radionuclides extracted from soil is expected to allow more precise estimation of their soil-to-plant transfer. Komatsuna (Brassica rapa L. var. perviridis) cultivated in experimental pots and actual fields was used for investigation. Soil samples collected from 19 agricultural fields in Aomori Prefecture were adapted for the pot experiment. We extracted 40 elements from the soil samples with pure water, 0.01 M HNO3, 1 M NH4OAc or 1 M NH4NO3, and analyzed their concentrations in the extracts. Their contents in komatsuna were determined, and their relationships with the concentrations in the extracts were investigated. Although the correlations between the concentrations in the plants and total concentration in the soils were not significant for most elements measured, zinc and lanthanide elements concentrations in the 0.01 M HNO3, 1 M NH4OAc and 1 M NH4NO3 extracts had significant positive correlations with those in the plants. These extraction methods were suitable for the estimation of phytoavailable fractions for those elements. Concentrations of Sr in the any extracted fractions did not correlate to those in the plants. However, Sr/Ca ratios in the NH4OAc extracted fraction showed significant correlation with the plant Sr concentrations. Although the Sr transfer factor was predicted by the NH4OAc-extractable Ca in soil, introducing the Mg concentration in that fraction and the total carbon concentration in soil as additional parameters could

  3. Chemical method of assessing the degree of biodegradation of wooden structural elements

    Directory of Open Access Journals (Sweden)

    T.A. Serova

    2014-05-01

    Full Text Available Wood is an environmentally friendly and lightweight building material that is sensible to the destrustion of various biological agents at non-observance of proper temperature and humidity regime. Wood-destroying white-rot and brown-rot fungi and micromycetes (mold have a leading position among biodestructors. This organisms use wood as the trophic base changing it’s chemical composition and correspondingly it’s mechanical properties. We investigated changes in the content of the main biopolymers of wood (cellulose and lignin and changes in ash content and moisture of the material under the influence of mold and wood fungi. We analyzed samples of wooden constructions with different biodestruction degree. We used chemical methods of extraction of cellulose and lignin from intact and diseased by fungi wood, method of calculation of material’s moisture and ash content. It was found that, with the development of deep destructions cellulose content is reduced by 20%, lignin content is reduced by 40%. Moisture and ash content of wood can also be used as markers of a certain degree of biodegradation.

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

    Science.gov (United States)

    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.

  5. 国际品牌酒店设计中的多元要素%Multivariate Elements of Design for World Class Hotels

    Institute of Scientific and Technical Information of China (English)

    宁奇峰

    2013-01-01

    对国内的国际品牌酒店设计中所要考虑的多元要素进行分析研究,指出建筑师作为整体设计协调人,应平衡处理好多元要素的矛盾,有效激发多元要素的正向叠加,创造设计亮点的方法.%Based on the multivariate elements that need to be considered in design for domestic world class hotels,this paper proposes the measures to coordinate contradiction between multivariate elements,to inspire the positive superposition of elements effectively,and to create bright spot of design.

  6. Gas phase chemical studies of superheavy elements using the Dubna gas-filled recoil separator - Stopping range determination

    International Nuclear Information System (INIS)

    Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40-270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction 244Pu(48Ca; 3n)289114. One decay chain assigned to an atom of 285112, the α-decay product of 289114, was observed.

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

    Science.gov (United States)

    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.

  8. Total reflection X-ray fluorescence applied to the chemical elements analysis of the mate tea infusion (Ilex-paraguariensis)

    International Nuclear Information System (INIS)

    The purpose was to evaluate simultaneously the chemical element concentrations from K to Sr (19≤Z≤38) range in six samples of mate tea (Ilex paraguariensis) infusion, commercially available in Paraguay and South of Brazil. The chemical analysis of this beverage has a great nutritional importance for the native people of these areas, due to their large daily consumption. For the determination of these elements the dry-ashing and total reflection X-rays fluorescence (TXRF) were used. The methodology showed limits of detection among 81 ng.mL-1 for K to 10 ng.mL-1 for Zn. Six infusion samples were prepared in triplicate, and the concentration was 3,8 to 10,2 μg.mL-1 for K, Ca and Mn, 0,21 to 1,07 μg. mL-1 for Fe and Zn and 0.03 to 0,17 μg.mL-1 for Ni, Cu, Br, Rb and Sr. The Mn and Ni concentrations are above the maximum permissible values for drinking water established by World Health Organization and Brazilian legislation (these organisms do not regulate the maximum permissible values for chemical elements in mate tea infusion). (author)

  9. Coupled chemo-electro-mechanical finite element simulation of hydrogels: I. Chemical stimulation

    International Nuclear Information System (INIS)

    Polyelectrolyte gels are viscoelastic adaptive materials with enormous swelling capabilities under the influence of different kinds of stimulation, e.g. chemical, electrical or thermal. This unique property makes them very attractive for 'pseudomuscular' actuators. In this paper we investigate the mechanism of the chemical stimulation, by changing the salt concentration in the solution bath surrounding the gel. By applying a fully coupled chemo-electro-mechanical model, the change of the concentrations, of the electric potential and of the displacement are investigated when varying the ambient chemical conditions. The change of the mechanical displacement and the gel geometry is realized by the change of the osmotic pressure difference between the gel and the solution. The volume change of the gel leads to a change in the concentration of bound anionic groups while keeping their mole number constant. It is shown that the full coupling of the mechanical and the chemo-electrical field is necessary and that it is a real improvement to the previously developed one-way chemo-electric to mechanical coupling. It is demonstrated that the fully coupled model works as a kind of limiter for the change of the chemo-electric unknowns and thus for the gel deformation. A qualitative comparison with experimental results shows the validity of the fully coupled chemo-electro-mechanical model for chemical stimulation

  10. Analysis of liquid evaporation system containing uranium and others chemical elements according to laws and standards in force

    International Nuclear Information System (INIS)

    Liquid evaporation has been world-wide sanctioned in the nuclear industry as a volume reduction technique for laboratory effluents or rad wastes. This fast technique has showed efficiency for non volatile chemical elements concentration. The resulting mud is chemically stable, physically homogeneous and biologically inhert. It is common that low radiation level liquids, containing uranium undergo evaporation, although its quantity in the mud can be not the limiting factor for the final deposition. It often occurs that depending on liquids to be evaporated other chemical elements as flour or heavy metals could avoid the deposition of the mud in the environment. The proposed evaporator works with solar heating, although electric energy could be used, and allow to evaporate 50 L of liquids per day. Volume reduction factor can reach 95% and the construction cost is very low. In this work there are analyzed evaporator characteristics and the limiting values established by Brazilian laws and standards, for those elements that are present in the resulting mud. The aim is to justify why zero discharge is preferred instead the deposition of the concentrate in the environment. (author)

  11. Mineralogy and chemical composition and distribution of rare earth elements of clay-rich sediments, Central Uganda

    International Nuclear Information System (INIS)

    In Uganda, Precambrian rocks are extensively weathered to sediments, which are locally altered to form considerable clay deposits. Clay-rich sediment samples were collected from the Kajjansi, Kitiko, Kitetika, and Ntawo valleys (central Uganda), all of which are currently used for traditional brick, tile, and pottery manufacture. The mineralogical and chemical characteristics, and source rocks of these clay-rich sediments is not well understood. A study using modern analytical techniques, such as XRD, to obtain the bulk mineralogical composition, and XRF and INAA analyses for whole rock major and trace element abundances was performed. The results show that the sediments are dominated by kaolinite and quartz, and minor phases include smectite, chlorite, and illite/muscovite. Whole rock chemistry shows that sediment samples rich in SiO2 have low Al, Fe, Sc and Cr contents. The high chemical index of alteration (CIA) values (87 to 96), chemical index of weathering (CIW) values around 98 and low contents of the alkali and alkali earth elements of the clay-rich sediments suggest a relatively more intense weathering source area. The clay-rich sediments as raw materials for industry were classified as silty clays from grain size analysis. The chemical and mineralogical composition results show that, taken as a whole, the clay-rich sediments possess characteristics satisfactory for brick production. The chondrite-normalized rare earth elements (REE) patterns of the clay-rich sediments show LREE enrichments and a negative Eu anomaly. The high chondrite-normalized La/Yb ratios, and Gd/Yb ratios lower than 2.0, confirm that the sediments are enriched in the LREEs. The mineralogical composition, REE contents, and elemental ratios in these sediments suggest a provenance from mainly felsic rocks, with only minor contributions from basic sources. The basic sediments were most likely derived from metasedimentary rocks, such as muscovite-biotite schists, which are characteristic

  12. Chemical extraction methods for assessment of phytoavailable fractions of elements in soils

    International Nuclear Information System (INIS)

    This study develops extraction methods of phytoavailable fractions of elements in soil for precise estimation of soil-to-plant transfer of radionuclides released from nuclear facilities, such as a reprocessing plant in Rokkasho. The soil-to-plant transfer factor based on the total concentration in soil is generally scattered over a few orders of magnitude. This large variance is likely attributable to ignorance of phytoavailability of radionuclides in soil. The transfer factor based on phytoavailable fractions of the radionuclides extracted from soil is expected to allow more precise estimation of their soil-to-plant transfer. Plant samples cultivated in experimental pots and actual fields were used for investigation. Soil samples collected from 19 agricultural fields in Aomori Prefecture were adapted for the pot experiment. We extracted 40 elements from the soil samples using pure water, 0.01 M HNO3, 1 M NH4OAc or 1 M NH4NO3, and analyzed their concentrations in the extracts. Their contents in the plant samples were determined, and their relations with the concentrations in the extracts were investigated. We had previously studied the relations using Komatsuna (Brassica rapa L. va. perviridis) in fiscal 2004, and reported the following results. The concentrations of Zn and lanthanide elements in the 0.01 M HNO3, 1 M CH3COONH4 and 1 M NH4NO3 extracts had significant positive correlations with those in the plants. Therefore, these extraction methods were suitable for estimation of phytoavailable fractions for the elements. Ratios of Sr/Ca in the NH4OAc extracted fraction also showed a significant correlation with the plant Sr concentrations. The transfer factors based on the ratios were confirmed to explain the Sr concentration in the Komatsuna samples collected from the actual fields, and they showed good agreement. We carried out the same experiment using orchardgrass (Dactylis glomerata), red clover (Trifolium pratense L.) and radish (Raphanus sativus L.) in

  13. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    International Nuclear Information System (INIS)

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conventional techniques have been achieved. This has resulted in minimum detection limits for transition metals of 8 x 107 atoms/cm2. SR-TXRF studies of the amount of metal contamination deposited on a silicon surface as a function of pH and oxygen content of the etching solutions have provided insights into the mechanisms of metal deposition from solutions containing trace amounts of metals ranging from parts per trillion to parts per billion. Furthermore, by using XANES to understand the chemical state of the metal atmos after deposition, it has been possible to develop chemical models for the deposition processes. Examples will be provided for copper deposition from ultra pure water and acidic solutions. (author)

  14. Simultaneous analysis of pesticides from different chemical classes by using a derivatisation step and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Raeppel, Caroline; Nief, Marie; Fabritius, Marie; Racault, Lucie; Appenzeller, Brice M; Millet, Maurice

    2011-11-01

    This work presents a new method to analyse simultaneously by GC-MS 31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC-MS method will be applied to the analysis of passive samplers (Tenax(®) tubes and SPME fiber) used for the evaluation of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent producing very specific fragments [M-57], was retained. However, diuron could not be derivatised and the isocyanate product was used for identification and quantification. Pesticides which did not need a derivatisation step were not affected by the presence of the derivatisation agent and they could easily be analysed in mixture with derivatised pesticides. The method can be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of various pesticides in atmospheric samples. PMID:21962330

  15. Effect of Extension and Type of Composite-Restored Class II Cavities on Biomechanical Properties of Teeth: A Three Dimensional Finite Element Analysis.

    Directory of Open Access Journals (Sweden)

    Azam Valian

    2015-04-01

    Full Text Available Controversy exists regarding cavity preparation for restoration of interproximal caries in posterior teeth in terms of preserving the tooth structure and suitable stress distribution. This study aimed to assess the effect of extension and type of class II cavities and the remaining tooth structure in maxillary premolars restored with composite resin on the biomechanical properties of teeth using finite element method (FEM.Using FEM, eight three-dimensional (3D models of class II cavities in maxillary premolars with variable mesiodistal (MD dimensions, variable thickness of the residual wall in-between the mesial and distal cavities and different locations of the wall were designed. Other dimensions were the same in all models. Cavities were restored with composite resin. A load equal to the masticatory force (200N was applied to the teeth. Finite element analysis (FEA was used to calculate the von Mises stress.Stress in the enamel margin increased by increasing the MD dimensions of the cavities. Deviation of the residual wall between the mesial and distal cavities from the tooth center was found to be an important factor in increasing stress concentration in the enamel. Increasing the MD dimensions of the cavity did not cause any increase in stress concentration in dentin.Increasing the MD dimensions of the cavities, decreasing the thickness of the residual wall between the mesial and distal cavities and its deviation from the tooth center can increase stress concentration in the enamel but not in dentin.

  16. Parent Stars of Extrasolar Planets. VIII. Chemical Abundances for 18 Elements in 31 Stars

    OpenAIRE

    Gonzalez, Guillermo; Laws, Chris

    2007-01-01

    We present the results of detailed spectroscopic abundance analyses for 18 elements in 31 nearby stars with planets. The resulting abundances are combined with other similar studies of nearby stars with planets and compared to a sample of nearby stars without detected planets. We find some evidence for abundance differences between these two samples for Al, Si and Ti. Some of our results are in conflict with a recent study of stars with planets in the SPOCS database. We encourage continued st...

  17. Chemical elements in the muscle tissues of European eel (Anguilla anguilla) from selected lakes in Latvia.

    Science.gov (United States)

    Rudovica, Vita; Bartkevics, Vadims

    2015-10-01

    Fish is a significant source of essential nutrients, as well as toxic elements in the human diet. Concentration of 17 elements was determined in muscles of eels (Anguilla anguilla) collected from five fishing lakes in the territory of Latvia. The concentration of main elements determined in muscle tissues varied within the following ranges: for Pb, 0.019-0.047; Cd, 0.0051-0.011; Hg, 0.13-0.36; Cu, 0.76-0.92; Zn, 28-42; and As, 0.13-0.23 mg kg(-1) wet weight. A positive correlation was revealed between the concentration of Hg in muscles and fish length in inland lakes. Concentration of metals in muscle tissues of eels from brackish coastal and inland lakes was without statistically significant difference. This research demonstrated that the elemental content of Cd and Pb in muscles of the examined fish was lower than the maximum allowed threshold set by the European Union legislation. Mercury content was over the threshold limit for all the analyzed eels if to compare with the Water Framework Directive Environmental Quality Standards. On other side, only 7% of analyzed fish have indicated values that are over threshold limits for mercury established by the European Union food legislation. The current study contributes to the implementation of Water Framework Directive in Latvia by collection of information necessary for the further protection measures of waters. To our knowledge, this study provides the first data on multielemental bioaccumulation in muscle tissues of European eels collected from fishing lakes of Latvia. PMID:26334326

  18. Chemical Elements in Mulch and Litterfall of Beech Ecosystems and Their Total Turnover

    OpenAIRE

    Mariyana I. Lyubenovа; Violeta G. Dimitrova

    2011-01-01

    The beech communities on the territory of Bulgaria had been objects of regional, local as well as large scale national investigations aiming their classification, determination of their ecological characteristics, conservation status, habitats etc. They are included as objects of the intensive monitoring of forest ecosystems in Bulgaria also. The investigations of chemical content of the litter – fall in these forests were conducted until now. The novelty of the present research is investiga...

  19. Chemical studies of rutherfordium (element 104). Pt. 3. Solvent extraction into triisooctylamine from HF solutions

    International Nuclear Information System (INIS)

    The extraction of element 104, rutherfordium (Rf), and its group 4 homologs into 0.25 M triisooctylamine (TIOA) in o,m,p-xylene from various concentrations of hydrofluoric acid was studied. This extraction system was of particular interest because all group 4 cations studies formed complexes with the same coordination number (CN) of 6. Therefore, species extracted were similar and the extractability depends on the radii of the fluoride complexes. The studies showed that the extractability for the group 4 elements in this system decreases in the order Ti>Zr∼Hf>Rf, in inverse order from the decrease in ionic radii Rf>Zr∼Hf>Ti. This order is different than the order in the hydrolysis, TBP-HCl, and TBP-HBr extraction systems where Rf, due to decreasing CN, behaves more similarly to Ti than to Zr and Hf. (orig.)

  20. Chemical analysis of the elements in UZrNb alloy at CDTN: preliminary investigation

    International Nuclear Information System (INIS)

    The complete determination of major, minor, and impurity element contents in nuclear fuel is essential for quality assurance in the production of nuclear fuels. The control over all the stages of the development of nuclear fuel involves a combination of different analytical methods such as spectrometric methods. The goal of our investigation is to develop and evaluate procedures for the determination of main elements and carbon impurity present in some uranium alloys. In this paper the element contents in U2.5Zr7.5Nb, U3Zr9Nb alloys and U6Nb, in weight percent, were investigated by means of scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), inductively coupled plasma mass spectrometry (ICP-MS), wavelength dispersive fluorescence spectrometry (XRF/WDS) and energy-dispersive X-ray spectroscopy (EDX). The total carbon was determined using a carbon analyzer in which the sample is oxidized to carbon dioxide (IR absorption). It was observed a satisfactory correlation between the results obtained by employed methods. (author)

  1. Effect of Organic Matter on Soil Chemical Properties and Corn Yield and Elemental Uptake

    OpenAIRE

    M. Afyuni; Y. Rezaenejad

    2001-01-01

    Due to high production of organic residues such as sewage sludge and compost, land application is probably the best way to prevent accumulated residues in the environment. However, the risk involved in the land application of organic residues should be evaluated prior to the assessment of their economic and fertilizer values. The objective of this study was to evaluate the effect of organic residues on soil chemical properties, yield and uptake of heavy metals and nutrients by corn (Zea mays ...

  2. Biorefine: Recovery of nutrients and metallic trace elements from different wastes by chemical and biochemical processes

    OpenAIRE

    Tarayre, Cédric; Fischer, Christophe; De Clercq, Lies; Michels, Evi; Meers, Erik; Buysse, Jeroen; Delvigne, Frank; Thonart, Philippe

    2014-01-01

    At present, most waste processing operations are not oriented towards the valorization of valuable reusable components such as nitrogen, phosphorus, potassium and even Metallic Trace Elements (MTEs). Currently, sewage sludge, for example is usually used as a fertilizer in agriculture, in energy production or in the field of construction. Ashes originating from sludge incineration contain heavy metals and minerals in large quantities. Manure is mainly used in agriculture, although considerable...

  3. Numerical simulation of isothermal chemical vapor infiltration process in fabrication of carbon-carbon composites by finite element method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The chemical vapor infiltration process in fabrication of carbon-carbon composites is highly inefficient and requires long processing time. These limitations add considerably to the cost of fabrication and restrict the application of this material. Efforts have been made to study the CVI process in fabrication of carbon-carbon composites by computer simulation and predict the process parameters, density, porosity, etc. According to the characteristics of CVI process, the basic principle of FEM and mass transport, the finite element model has been established. Incremental finite element equations and the elemental stiffness matrices have been derived for the first time. The finite element program developed by the authors has been used to simulate the ICVI process in fabrication of carbon-carbon composites. Computer color display of simulated results can express the densification and distributions of density and porosity in preform clearly. The influence of process parameters on the densification of preform has been analyzed. The numerically simulated and experimental results give a good agreement.

  4. theories of class

    Science.gov (United States)

    Gaiotto, Davide; Razamat, Shlomo S.

    2015-07-01

    We construct classes of superconformal theories elements of which are labeled by punctured Riemann surfaces. Degenerations of the surfaces correspond, in some cases, to weak coupling limits. Different classes are labeled by two integers ( N, k). The k = 1 case coincides with A N - 1 theories of class and simple examples of theories with k > 1 are orbifolds of some of the A N - 1 class theories. For the space of theories to be complete in an appropriate sense we find it necessary to conjecture existence of new strongly coupled SCFTs. These SCFTs when coupled to additional matter can be related by dualities to gauge theories. We discuss in detail the A 1 case with k = 2 using the supersymmetric index as our analysis tool. The index of theories in classes with k > 1 can be constructed using eigenfunctions of elliptic quantum mechanical models generalizing the Ruijsenaars-Schneider integrable model. When the elliptic curve of the model degenerates these eigenfunctions become polynomials with coefficients being algebraic expressions in fugacities, generalizing the Macdonald polynomials with rational coefficients appearing when k = 1.

  5. Thermochromatographic method of separation of chemical elements in nuclear and radiochemistry

    International Nuclear Information System (INIS)

    The state of the art in the title field including vacuum thermochromatography and sublimatography is discussed. Thermochromatography has proven to be effective in studying properties of the transactinoid elements, in separation of products from spallation reactions, in the production of radionuclides for nuclear medicine. Applications of the method for the radiochemical activation analysis seem especially prospective. From the theoretical side, the dependence of deposition temperatures on experimental parameters is reasonably well understood for uniform surfaces while reported theoretical calculations of peak shapes have not yet been confronted with the experimental data extensively enough. The case of nonuniform surfaces is a problem for future research. Some interesting non-analytical applications of the method can be suggested, such as measuring the diffusion coefficients of the adsorbates and enthalpies and entropies of adsorption. (orig.)

  6. Elemental chemical characterization of coins of currently national circulating by X-ray fluorescence non-destructive techniques

    International Nuclear Information System (INIS)

    Given the frequent counterfeit bills and coins is proposed in this paper to identify the elemental chemical composition; for now, the current official currencies circulating in our country, by Energy Dispersive X-ray Fluorescence technique and non-destructive methods, the goal is to compare with the false and establish the differences that could help identify them immediately taking advantage of the fast response of this technique. Have been identified the elements Al in the coins of 5 cents, Cu and Zn for 10 and 20 cents, Ni, Cu and Zn for 50 cents and a Un Nuevo Sol and Cr, Cu and Zn 2 coins 5 Nuevos Soles. 57 Peruvian coins of different production years and a counterfeit coin of 5 Nuevos Soles have been analyzed, finding Cu and Zn in central part and Fe in circulating edge ring, looking for this one the absence of Ni and Cr, which in the official currency was found. (authors).

  7. Bacterial disproportionation of elemental sulfur coupled to chemical reduction of iron or manganese

    DEFF Research Database (Denmark)

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

    1993-01-01

    A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and...... 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 FeCO(3). Further enrichment with manganese oxide, MnO(2), instead of FeOOH yielded stable cultures which formed sulfate during concomitant...... reduction of MnO(2) to Mn. Growth of small rod-shaped bacteria was observed. When incubated without MnO(2), the culture did not grow but produced small amounts of SO(4) and H(2)S at a ratio of 1:3, indicating again a disproportionation of S. The observed microbial disproportionation of S only proceeds...

  8. Assessing the Amount of Chemical Elements in Biodegradable Agricultural Wastes and ASH

    OpenAIRE

    Rasa Kvasauskienė; Pranas Baltrėnas

    2011-01-01

    Biodegradable agricultural wastes such as manure, has long been used as an organic fertilizer that improves soil structure, enriches the soil with micro-organisms and micro-elements necessary for plants and promotes humus formation. Manure can also be successfully used as a renewable energy source directly combusting and extracting energy. The carried out investigation showed that the incineration of manure remaining in ashes could also be used as a fertilizer. Waste combustion reduces its vo...

  9. The effects of music, relaxation and other suggesto- 24 pedic elements in a primary school German class. An experimental investigation

    Directory of Open Access Journals (Sweden)

    Uschi Felix

    2013-02-01

    Full Text Available This nine week study set out to test whether, in addition to good communicative teaching, music, relaxation, suggestion, and the adoption by the students of German personalities, would have a positive effect on students' language self-concept, attitude and achievement. The subjects were twenty-eight fourth and fifth year students (average age nine years eight months.at a metropolitan Catholic Primary School in South Australia. Pairs of students were matched for sex, year level and language self-concept and then allocated at random to the control or the experimental group. Both groups were taught German by the same teacher for four weeks of seventy minutes daily instruction. The children had no previous experience of learning a foreign language. Video tapes were taken of both groups during teaching for comparison of teacher and student behaviour by independent raters. Tests were administered at the end of the course testing all four language skills. t-Test analyses showed that the experimental class performed significantly better on all language tasks than the control group. Repeated measures Anova showed that both self-concept and attitude improved significantly in the experimental class. Rank sum analysis of the video ratings showed that attention rate was significantly better in the experimental class. Die doel van hierdie studie van nege weke was om te toets ofmusiek, ontspanning, suggestie en die aanneem van Duitse persoonlikhede deur die skoliere, tesame met goeie kommunikatiewe onderrig 'n positiewe uitwerking op die studente se taalselfkonsep, houding en prestasie sou he. Ag-en-twintig vierde- en vyfdejaarskoliere ( gemiddeld nege jaar en agt maande oud verbonde aan 'n stedelike Katolieke laerskool in Suid-Australie is gebruik. Skoliere is in pare gekies op grond van geslag, skoolstanderd en taalselfkonsep en op 'n willekeurige basis, of in die kontrole- of in die eksperimentele groep ingedeel. Beide groepe is vier weke lank onderrig. Die

  10. Correlation Between Chemical Element Contents in Tree Rings and Soils

    Institute of Scientific and Technical Information of China (English)

    QIANJUN-LONG; KESHAN-ZHE; 等

    1993-01-01

    The annual growth rings of ten trees and the soils near the tree roots were sampled from the mining ares of lead-and zinc-dominant metals in the Xixia Mountain,Nanjing,for the determination of chemical element contents.The study results showed that the elemental contents in the tree rings were correlated with those in the soils,i.e.,the elemental contents in the tree rings increased with those in the soils,even in the cases of different environments and different tree species.Therefore,a time-concentration sequence could be set up on the basis of determining the elemental contents in the successive annual growth rings of trees to qualitatively reflect the annual variations of relevant elements in the soils,and a time-concentration sequence of elemental contents in soils could also be established in terms of related model to reproduce the dynamic changes of the surroundings.

  11. Chemical composition of the ore and occurrence state of the elements in Jingbaoshan platinum- palladium deposit

    Institute of Scientific and Technical Information of China (English)

    SONG Huanbin; HE Mingqin; ZHANG Shangzhong; YI Fenghuang

    2008-01-01

    The Jingbaoshan platinum-palladium deposit is China's largest independent PGM (platinum-group metals) deposit so far discovered. There are eleven kinds of useful components in the ore: Pt, Pd, Os, Ir, Ru, Rh, Au, Ag, Cu, Ni, and Co. The platinum-group elements, gold and silver occur in the form of minerals in ores. twenty-five kinds of precious metal minerals have been found, of which twenty one belong to the platinum-group minerals. The minerals are very small in grain size. Copper occurs mainly as copper sulfide with a small amount of free copper oxide, and the beneficiated copper accounts for 95.21%. Nickel occurs mainly as nickel sulfide, and some nickel silicate and nickel oxide occur in the ore. The beneficiated nickel accounts for 72.03%. Cobalt occurs mainly as cobalt sulfide, and there are some cobalt oxide and other kinds of cobalt. The beneficiated cobalt accounts for 77.58%.

  12. Speciation of trace elements in biological samples by nuclear analytical and related techniques coupled with chemical and biochemical separation

    International Nuclear Information System (INIS)

    In the past, most analytical problems relating to biological systems were addressed by measuring the total concentrations of elements. Now there is increasing interest of the importance of their chemical forms, in which an element is present in biological systems, e.g., the oxidation state, the binding state with macromolecules, or even the molecular structure. The biological effects of chromium, which is classified as an essential nutrient, are dependent upon its oxidation. state. In general, trivalent chromium is biochemically active, whereas hexavalent chromium is considered to be toxic. Mercury is one of serious environmental persistent pollutants. However, organic forms of mercury are known to possess much higher toxicity than inorganic mercury. Therefore, information on speciation is critically required in order to better understanding of their bioavailability, metabolism, transformation, and toxicity in vivo. Recently, chemical speciation of selenium, mercury, copper, zinc, iron, and so on, has been investigated by INAA, ICP-MS, XRF, EXAFS and related techniques combined with chemical and biochemical separation (extraction, chromatography, gel electrophoresis, etc.). INAA, XRF, and ICP-MS have superior advantages in aspect of multielemental analysis with high accuracy and sensitivity, which render the possibility of analyzing various elements of interest simultaneously. These offline or online techniques have been flexibly applied to different biological matrixes, such as human hair, serum, urine, various tissues and organs in our researches. In addition, EXAFS provides structural information about the moiety of metal centers up to a distance of approximately 4-5 Anstrom. For instance, hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Imbalance of elements, such as Se, Zn, Fe, Cu, Cd, Ca, etc., has been found in the whole blood or serum of patients with HCC. We found that the profiles of Se, Cd, Fe, Zn and Cu-containing proteins

  13. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    CERN Document Server

    Pianetta, Piero A; Baur, K; Brennan, S; Homma, T; Kubo, N

    2003-01-01

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO sub 2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conv...

  14. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods

    International Nuclear Information System (INIS)

    This thesis is related to comparative studies of the chemical properties of molecular complexes containing lanthanide or actinide trivalent cations, in the context of the nuclear waste disposal. More precisely, our aim was a quantum chemical analysis of the metal-ligand bonding in such species. Various theoretical approaches were compared, for the inclusion of correlation (density functional theory, multiconfigurational methods) and of relativistic effects (relativistic scalar and 2-component Hamiltonians, relativistic pseudopotentials). The performance of these methods were checked by comparing computed structural properties to published experimental data, on small model systems: lanthanide and actinide tri-halides and on X3M-L species (X=F, Cl; M=La, Nd, U; L = NH3, acetonitrile, CO). We have thus shown the good performance of density functionals combined with a quasi-relativistic method, as well as of gradient-corrected functionals associated with relativistic pseudopotentials. In contrast, functionals including some part of exact exchange are less reliable to reproduce experimental trends, and we have given a possible explanation for this result . Then, a detailed analysis of the bonding has allowed us to interpret the discrepancies observed in the structural properties of uranium and lanthanides complexes, based on a covalent contribution to the bonding, in the case of uranium(III), which does not exist in the lanthanide(III) homologues. Finally, we have examined more sizeable systems, closer to experimental species, to analyse the influence of the coordination number, of the counter-ions and of the oxidation state of uranium, on the metal-ligand bonding. (author)

  15. Rare-element granitic pegmatite of Miocene age emplaced in UHP rocks from Visole, Pohorje Mountains (Eastern Alps, Slovenia): accessory minerals, monazite and uraninite chemical dating

    Science.gov (United States)

    Uher, Pavel; Janák, Marian; Konečný, Patrik; Vrabec, Mirijam

    2014-04-01

    The granitic pegmatite dike intruded the Cretaceous UHP rocks at Visole, near Slovenska Bistrica, in the Pohorje Mountains (Slovenia). The rock consists mainly of K-feldspar, albite and quartz, subordinate muscovite and biotite, while the accessory minerals include spessartine-almandine, zircon, ferrocolumbite, fluorapatite, monazite- (Ce), uraninite, and magnetite. Compositions of garnet (Sps48-49Alm45-46Grs + And3-4 Prp1.5-2), metamict zircon with 3.5 to 7.8 wt. % HfO2 [atom. 100Hf/(Hf + Zr) = 3.3-7.7] and ferrocolumbite [atom. Mn/(Mn + Fe) = 0.27-0.43, Ta/(Ta + Nb) = 0.03-0.46] indicate a relatively low to medium degree of magmatic fractionation, characteristic of the muscovite - rare-element class or beryl-columbite subtype of the rare-element class pegmatites. Monazite-(Ce) reveals elevated Th and U contents (≤11 wt. % ThO2, ≤5 wt. % UO2). The monazite-garnet geothermometer shows a possible precipitation temperature of ~495 ± 30 °C at P~4 to 5 kbar. Chemical U-Th-Pb dating of the monazite yielded a Miocene age (17.2 ± 1.8 Ma), whereas uraninite gave a younger (~14 Ma) age. These ages are comtemporaneous with the main crystallization and emplacement of the Pohorje pluton and adjacent volcanic rocks (20 to 15 Ma), providing the first documented evidence of Neogene granitic pegmatites in the Eastern Alps. Consequently, the Visole pegmatite belongs to the youngest rare-element granitic pegmatite populations in Europe, together with the Paleogene pegmatite occurrences along the Periadriatic (Insubric) Fault System in the Alps and in the Rhodope Massif, as well as the Late Miocene to Pliocene pegmatites in the Tuscany magmatic province (mainly on the Island of Elba).

  16. Analytical quality control of chemical element contents in human hair determined by INAA, ICP-ES and ICP-MS

    International Nuclear Information System (INIS)

    Full text: Human hair analysis is often used in studies of exposure of such elements as As, Hg, Pb, Cd and in estimation of nutritional status of many chemical elements too. Estimation of precision and accuracy of analytical determination or chemical element contents in human hair samples by combination of four methods: 1) instrumental neutron activation analysis with registration ol short-lived radionuclides radiations (INAA-SL), 2) instrumental neutron activation analysis with using long-lived radionuclides (INAA-LL), 3) atomic emission spectrometry and 4) mass-spectrometry with inductively coupled plasma (ICP-AES and ICP-MS respectively) was made using certified reference materials (CRM) NIES No 13 (human hair, Japan) and GBW09101 (human hair, China) as the subject. For estimation of repeatability of the results 10 samples weighting around 50 mg were Measured by one sample per one labor shift during 10 labor shifts. Two operators carried out the measurements alternately. It was shown that no less than 38 elements were available for analysis in human hair samples by INAA: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, I, K, La, Lu, Mg, Mn, Na, Nd, Rb, S, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Tm, Yb, Zn. For ICP-AES coupled with ICP-MS the maximum available elements were 40: Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Ge, Hg, I, K, La, Li, Mg, Mn, Mo, Ni, P, Pb, Pt, Rb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, W, Zn, Zr. All together the complex of four methods allow detect in human hair 58 different elements: Ag, Al, As, Au, B, Ba, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cu, Cs, Eu, Fe, Ga, Gd, Ge, Hf, Hg, I, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pt, Rb, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Th, Ti, Tl, Tm, V, W, Yb, Zn, and Zr. However: 1) INAA-SL of single sample with relative uncertainty (determined as ±2 RSD) less than ±10% allows to estimate mass fractions of no one element; within range from ±10% to <±20% - only Cl; within range

  17. Chemical modelling of trace elements in pore water from PFBC residues containing ammonia

    International Nuclear Information System (INIS)

    Ammonia is added to the PFBC process with the purpose to reduce the emissions of NOx in the stack gases. The design of the system for cleaning the stack gases will lead to an increased adsorption of ammonia and an accumulation of soluble ammonium salts in the cyclone ash from PFBC processes. This can be an environmental problem since the amounts will increase over the coming years and there will be a need to dispose the residues. When infiltrating rainwater penetrates the disposed residues ammonia and ammonium salts result in a contamination of the pore water with ammonia in the disposed residues. This entail the solubility of several trace elements in the residues that form soluble complexes with ammonia will increase and cause an increased contamination of groundwater and surface water. In this study the increased solubilities is calculated for the trace elements cadmium, cobalt, copper, mercury, nickel, silver and zinc in the residues using thermodynamical data. The calculations have been performed with probable solid phases of the trace elements at oxidizing and reducing conditions as a function of pH and at varying concentration of ammonia in the pore water. The thermodynamic calculations have been performed with the geochemical code EQ3NR. The results from the calculations show that as a concentration of 17 mg NH3/l in the pore water of the residues increases the solubilities for copper and silver. If the concentration of ammonia increases to 170 mg NH3/l will the solubilities increase also for cadmium, nickel and zinc. (12 refs., 39 figs.)

  18. Semiquantitative and quantitative measurements for EDXRF in elemental chemical composition of pigments

    International Nuclear Information System (INIS)

    X-Ray fluorescence technique is largely used in the characterization of art and archaeological objects for restoration and conservation, allowing a multi-elemental, simultaneous and non destructive analysis. In this work it was used a portable XRF equipment of XRF that consists of a 238 Pu source ( 13,6 and 17,2 keV; 95 mCi) and a SI-PIN detector coupled to a 8 k multichannel analyser. The results were collected by a palmtop computer and later analysed in a PC, through the program AXIL-QXAS. The acquisition time for each measurement was 500 s. The measurements were accomplished in a wood sculpture (Santa Luzia image, number 164) from the collection of the Museu de Etnologia da Universidade de Sao Paulo (MAE-USP), in the following regions: (STL1) inferior side of the wood base exposed without finishing, (STL2) frontal inferior base of the pedestal (dark blue) (STL3), inferior part of the frontal dress (gold), (STL4) medium part of the dress (clear blue) (STL5) mantle (red), (STL6) back central lock of the hair in the backs (black), (STL7) right cheek (flesh-coloured) and (STL8) mantle (gold). The elements found in the STL1 region were: Al, Ca, Fe and a high concentration of Zn. In the region STL2 were found Al, C, Fe, Zn and the key element Cu. In the region STL3 - Ca, Zn and the key element Au. In the region STL4 it was found Zn and the key element Cu. In the region STL5 the key element S and Hg. In the region STL6 were found Fe, Ca, S and Hg. In the region STL 7 were found Al, Cu, Hg and Zn. In the region STL8 were found Ca, Al and Au, with high concentration. It was concluded that the possible pigments would be: STL2 and STL4 - CuCO3. Cu(OH)2 + ZnO; STL3 and STL8 - Au; STL5 - HgS, STL6 - HgS mixed with other oxides, possibly of Fe and Mn, and STL 7 - HgS + ZnO. Standard samples of wood painted with pigments of the colors white, blue, red, rose, flesh color and green were also made. Through the XRF method it was verified that the white pigment is TiO2, the red one

  19. PIXE and ICP analysis of chemical elements in the downer cow syndrome

    International Nuclear Information System (INIS)

    The aim of this study was the microelemental analysis of blood serum samples collected from healthy and ill cows (downer cow syndrome DCS). The origin of this syndrome is uncertain but the clinical experience denotes that the DCS is advanced by the hypocalcaemic paresis of parturition. The diminution of some nutritive elements from food can be a cause of DCS. The cows are more sensitive to the diminution of P in food in comparison with the diminution of Ca. Another interesting aspect about the origin of DCS is the ratio Ca/P in food. The samples were collected from cows at some animal farms: 20 healthy cows and 12 DCS cows breeds on the same conditions. Concentrations of P, Cl, K, Ca and Fe elements were obtained by using particle induced X - ray emission (PIXE) and inductively coupled plasma (ICP). The mineral concentrations in the serum have values in normal limits for healthy cows even during the winter, when the mineral content of dry food is very poor. On the other hand, we can observe important decreases under the normal limits of the amount of Ca, P and Mg in the blood serum of DCS cows. It is easy to see the tendency of the DCS animals to have hypocalcemia and hypophosphataemia. Those perturbations can be the causes of the installations of the ill cows in the lypostatic and decubital attitudes. (authors)

  20. Comparison of sewage sludge and chemical fertilizer application on yield and concentration of some nutrients in spinach (Spinosa olerace L. in three textural classes of a calcareous soil

    Directory of Open Access Journals (Sweden)

    A. Ronaghi

    2011-07-01

    Full Text Available Addition of sewage sludge (SS in soil causes increasing soil organic matter, which in turn improves soil physical properties, and could supply part of the nutrients required by plants. For comparison of SS application and chemical fertilizer treatment (CFT on yield and concentration of some macro and micro nutrients in spinach, a greenhouse factorial experiment, arranged in a completely randomized design (CRD, was conducted with three replications. The first factor included SS levels (0, 10, 20, 40 and 80 gr kg-1 and the second factor was soil textural classes (clay loam, sandy loam and sandy. A CFT was also used to compare its affect with that of SS levels. Results showed that addition of all levels of SS caused significant increase in the weight of spinach shoots in three soil textures. Application of all SS levels caused significant increase of nitrogen (N, phosphorous (P, iron (Fe, zinc (Zn, copper (Cu and manganese (Mn concentration in spinach shoots. With SS application, none of the nutrients’ concentration in spinach reached the toxic level. The amounts of cadmium (Cd and lead (Pb were not detectable in shoots. However, in frequent application of SS, especially at high levels, it is necessary to measure and detect these elements in plants. Effect of fertilizer in increasing yield and concentration of nutrients was less than the 40 and 80 gr kg-1 SS treatments. Considering the Fe and Zn deficiency in calcareous soils, application of SS can be effective for combating this deficiency. Prior to any recommendation of SS application, the results of this research need to be verified under field conditions.

  1. Micro-PIXE for the quantitative imaging of chemical elements in single cells

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, R. [Univ. Bordeaux, CENBG, Gradignan (France); CNRS, IN2P3, CENBG, Gradignan (France)

    2013-07-01

    Full text: The knowledge of the intracellular distribution of biological relevant metals is important to understand their mechanisms of action in cells, either for physiological, toxicological or pathological processes. However, the direct detection of trace metals in single cells is a challenging task that requires sophisticated analytical developments. The aim of this seminar will be to present the recent achievements in this field using micro-PIXE analysis. The combination of micro-PIXE with RBS (Rutherford Backscattering Spectrometry) and STIM (Scanning Transmission lon Microscopy) allows the quantitative determination of trace metal content within sub-cellular compartments. The application of STlM analysis will be more specifically highlighted as it provides high spatial resolution imaging (<200 nm) and excellent mass sensitivity (<0.1 ng). Application of the STIM-PIXE-RBS methodology is absolutely needed when organic mass loss appears during PIXE-RBS irradiation. This combination of STIM-PIXE-RBS provides fully quantitative determination of trace element content, expressed in μg/g, which is a quite unique capability for micro-PIXE compared to other micro-analytical methods such as the electron and synchrotron X-ray fluorescence or the techniques based on mass spectrometry. Examples of micro-PIXE studies for subcellular imaging of trace elements in the various fields of interest will be presented such as metal-based toxicology, pharmacology, and neuro degeneration [1] R. Ortega, G. Devés, A. Carmona. J. R. Soc. Interface, 6, (2009) S649-S658. (author)

  2. Micro-PIXE for the quantitative imaging of chemical elements in single cells

    International Nuclear Information System (INIS)

    Full text: The knowledge of the intracellular distribution of biological relevant metals is important to understand their mechanisms of action in cells, either for physiological, toxicological or pathological processes. However, the direct detection of trace metals in single cells is a challenging task that requires sophisticated analytical developments. The aim of this seminar will be to present the recent achievements in this field using micro-PIXE analysis. The combination of micro-PIXE with RBS (Rutherford Backscattering Spectrometry) and STIM (Scanning Transmission lon Microscopy) allows the quantitative determination of trace metal content within sub-cellular compartments. The application of STlM analysis will be more specifically highlighted as it provides high spatial resolution imaging (<200 nm) and excellent mass sensitivity (<0.1 ng). Application of the STIM-PIXE-RBS methodology is absolutely needed when organic mass loss appears during PIXE-RBS irradiation. This combination of STIM-PIXE-RBS provides fully quantitative determination of trace element content, expressed in μg/g, which is a quite unique capability for micro-PIXE compared to other micro-analytical methods such as the electron and synchrotron X-ray fluorescence or the techniques based on mass spectrometry. Examples of micro-PIXE studies for subcellular imaging of trace elements in the various fields of interest will be presented such as metal-based toxicology, pharmacology, and neuro degeneration [1] R. Ortega, G. Devés, A. Carmona. J. R. Soc. Interface, 6, (2009) S649-S658. (author)

  3. Physical features of accumulation and distribution processes of small disperse coal dust precipitations and absorbed radioactive chemical elements in iodine air filter at nuclear power plant

    CERN Document Server

    Ledenyov, Oleg P; Poltinin, P Ya; Fedorova, L I

    2012-01-01

    The physical features of absorption process of radioactive chemical elements and their isotopes in the iodine air filters of the type of AU-1500 at the nuclear power plants are researched. It is shown that the non-homogenous spatial distribution of absorbed radioactive chemical elements and their isotopes in the iodine air filter, probed by the gamma-activation analysis method, is well correlated with the spatial distribution of small disperse coal dust precipitations in the iodine air filter. This circumstance points out to an important role by the small disperse coal dust fractions of absorber in the absorption process of radioactive chemical elements and their isotopes in the iodine air filter. The physical origins of characteristic interaction between the radioactive chemical elements and the accumulated small disperse coal dust precipitations in an iodine air filter are considered. The analysis of influence by the researched physical processes on the technical characteristics and functionality of iodine ...

  4. Native bromeliads as biomonitors of airborne chemical elements in a Brazilian restinga forest

    International Nuclear Information System (INIS)

    Epiphytic bromeliads have been used as biomonitors of air pollution since they have specialized structures in leaves for absorbing humidity and nutrients available in the atmosphere. Leaves of five bromeliad species were collected in the conservation unit Parque Estadual Ilha do Cardoso, Sao Paulo State, Brazil, and analyzed by INAA. Vriesea carinata was the species showing most accumulation, with the highest mass fractions of K, Na, Rb and Zn. Similar results were previously found for the same species collected in the dense ombrophilous forest. Chemical composition of bromeliads provided an indication of the atmosphere status in the conservation unit. (author)

  5. PHYSIC AND CHEMICAL BASIS FOR THE INVOLVEMENT OF D-ELEMENTS OF THE FOURTH GROUP (TITANIUM, ZIRCONIUM, HAFNIUM) IN THE SYNTHESIS OF BUILDING AND SILICATE MATERIALS

    OpenAIRE

    BOLSHAKOV V. I.; Savin, Yu. L.; O. P. Prykhodko; L. S. Savin; Kulbashnyi, V. M.

    2007-01-01

    In the paper the studies of physico-chemical grounds of involving the fourth group elements (titanium, zirconium, hafnium) for syntheses of construction silicate materials are presented. The physico-chemical approach proposed allows involving the great group of technogenic titanium-containing semi-products, concentrates, slags and slimes for production of construction silicate materials and manufacture the products and building structures.

  6. PHYSIC AND CHEMICAL BASIS FOR THE INVOLVEMENT OF D-ELEMENTS OF THE FOURTH GROUP (TITANIUM, ZIRCONIUM, HAFNIUM) IN THE SYNTHESIS OF BUILDING AND SILICATE MATERIALS

    OpenAIRE

    BOLSHAKOV V. I.; Savin, Yu. L.; O. P. Prykhodko; L. S. Savin; Kulbashnyi, V. M.

    2008-01-01

    In the paper the studies of physico-chemical grounds of involving the fourth group elements (titanium, zirconium, hafnium) for syntheses of construction silicate materials are presented. The physico-chemical approach proposed allows involving the great group of technogenic titanium-containing semi-products, concentrates, slags and slimes for production of construction silicate materials and manufacture the products and building structures.

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

    Science.gov (United States)

    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

  8. Study of chemical and electrochemical properties of some elements in molten NaAlCl

    International Nuclear Information System (INIS)

    We describe a study of the electrochemical and chemical properties in molten mixtures of Aluminium Chloride-Sodium chloride, at 210 deg. C and the concept of acidity, related to chloride activity, is previously summarized. In a first part, the study of Mercury and Cadmium by means of electro-analytical techniques, states the Hg2+2, Hg2+, Cd2+2 and Cd2+ ions and their acid properties. Some diagrams Equilibrium potential vs acidity are the synthesis of these results. In a second part, it is shown that a nickel electrode is an indicator of the presence of oxide ions; from interpretation of electrochemical results, O2 appears to behave, in terms of the chloro-acido-basicity concept, as a strong di-base, giving the solvated form AlOCl-2, or a strong tri-base giving AlOCl. A saturation effect by Al2O3 appears when the oxide concentration is increased; the solubility of Al2O3 versus acidity is determined from the electrochemical results. In a third part, results for the Ni/Ni(II) or HCl/H2O systems are related to dissolved oxide ion presence in chloroaluminate melts; elimination of oxide ions, through H2O formation, by reaction with HCl is noteworthy. (author)

  9. 生化反应的五行归属%Anfive elements classification of bio-chemical reactions

    Institute of Scientific and Technical Information of China (English)

    徐天成

    2015-01-01

    五行学说提供了对事物进行系统分类的合理方法。人类体内充满了复杂的生物化学反应体系,能否用五行学说的基本规律归纳生物化学反应体系值得探讨。在以往相关研究的基础上,本文利用五行思想对生化反应的物质和反应类型进行分类,用简洁的中医学规律研究复杂的生化反应过程,这种新思路对药物研究、中西医结合学科的发展等具有挖掘价值。%Thefive elements theory provides us a system classification of all things so we can do the research in a much reasonable way. Further more, our bodies are full of complicated bio-chemical reactions and thefive elements theory should also be applicable to those reaction systems. This paper will try to make use of thefive elements theory to carry on an innovative classification of different types of bio-chemical reactions with the help of the former foundation of related researches, to make the complicated bio-chemical reactions easy to understand, and point out that this kind of lately academic thought is of great significance to the medicine researches as well as the integrated traditional Chinese and western medicine.

  10. Contents and spatial distributions of chemical elements in soil at the ancient roasting site Pšenk (Idrija area, Slovenia

    Directory of Open Access Journals (Sweden)

    Tamara Teršič

    2010-12-01

    Full Text Available Analysis for 35 chemical elements (Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, La, Mg, Mn, Mo, Na,Ni, P, Pb, S, Sb, Sc, Se, Sr, Th, Ti, Tl, U, V, W, Zn was performed in soil and SOM (soil organic matter; 0–5 cm at theancient roasting site P{enk in the surroundings of Idrija, which is highly contaminated with Hg. It was estimatedthat natural values of Al, Ba, Fe, K, Mn, Ni and Zn show normal distribution, while for the elements As, Au, Bi, Ca,Cd, Co, Cr, Cu, Ga, La, Mg, Mo, P, Pb, Sc, Se, Sr, Th, Tl, U in V the logarithms of elemental contents were considerednormally distributed. Contents of the analyzed elements in the sampling material are mostly within the normalvalues for soils as also within Slovenian and European averages for soil. High contents of As were determined insoils from investigated roasting site, reaching as much as 122 mg/kg in the depth of 5–20 cm. Additionally Cd, Mo,Pb and U contents in the soil (5–20 cm are higher compared to natural soils. Cd and Mo show somewhat increasedcontents also in SOM from studied roasting site.

  11. Concentrations of Chemical Elements in Willow Biomass Depend on Clone, Site and Management in the Field

    DEFF Research Database (Denmark)

    Liu, Na; Jørgensen, Uffe; Lærke, Poul Erik

    2016-01-01

    Eight willow (Salix) clones (Inger, Klara, Linnea, Resolution, Stina, Terra Nova, Tora, Tordis) were planted on two soil types in Denmark. The biomass quality was evaluated after 3 years of growth by measuring differences in concentrations of 14 elements associated with ash behavior during...... 22, 27, 35, and 23 % higher concentrations of K, S, Ca, and total ash than the other clones. In addition to clone and site, appropriate management could further improve the fuel quality of willow biomass. When shoots of Inger were harvested annually (1-year shoots) high concentrations of K and Cl...... were found in all three consecutive harvests, but concentrations decreased significantly when rotation length was extended beyond 1 year of growth. Significant decreases of Mg, Na, P, S, and Zn were also registered from 2- to 3-year-old shoots. No difference in quality of biomass was found between two...

  12. The origins of light and heavy r-process elements identified by chemical tagging of metal-poor stars

    CERN Document Server

    Tsujimoto, Takuji

    2014-01-01

    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 gamma-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 pr...

  13. Chemical land improvement salty ground of the Tyumen region and its influence on the maintenance of heavy metals and radioactive elements in soil

    International Nuclear Information System (INIS)

    It is considered after action chemical land improvement salty ground phosphorus laster alter 34 years on the maintenance and redistribution of heavy metals and radioactive elements in a meter structure ground.

  14. Determination of rare earth elements in high purity scandium using chemical neutron activation analysis

    International Nuclear Information System (INIS)

    The present work describes a simple and efficient method to preconcentrate the traces of rare earth elements (REEs) from large quantities of scandium (0.5-2.0 g) on a small column of Dowex 50 X 8, using ethylene diamino tetra acetic acid (EDTA) as complexing agent. The developed procedure is pH dependent and for the quantitative separation, pH variation studies were carried out to optimize the process, using suitable buffer. Under optimized conditions, scandium comes out as effluent while REEs are retained on the column. The retained analytes were subsequently desorbed from the column, using suitable acid and were quantified using neutron activation analysis. The separation of REEs from scandium was found to be essentially complete as the analyte recoveries were found to be > 95%. Standard addition method as well as tracer studies were carried out to check the validity of this procedure. The overall reproducibility of the procedure was 2-10%. (author)

  15. Transuranium elements in organic chemical forms

    International Nuclear Information System (INIS)

    It is very important to achive an understanding what role organic matter plays in the behavior of transuranium elements in the environment. This paper reports the studies on characteristics of fallout Pu and Am in soil closely related to soil organic matter, and interaction of humic acid and Am (III) in aqueous solution. From the results obtained, it was suggested that the humic acids had strong interaction with transuranium elements, but such soluble complexes were removed soon from the solution by coagulation and sorption on soil. (author)

  16. Separation and sampling technique of light element isotopes by chemical exchange process

    International Nuclear Information System (INIS)

    Lithium and boron isotope separation technique were studied. Granulation of lithium isotope separation agent was carried out by cure covering in solution. Separation of lithium isotope was stepped up by ammonium carbonate used as elusion agent. Styrene and ester resin derived three kinds of agents such as 2-amino-1, 3-propanediol (1, 3-PD), 2-amino-2-methyl-1, 3-propanediol (Me-1,3-PD) and tris(2-hydroxyethyl)amine (Tris) were used as absorbent.The ester resin with Tris showed larger amount of adsorption (1.4 mmol/g) than other resins. However, all resins with agent indicated more large adsorption volume of boron than the objective value (0.5 mmol/g). Large isotope shift was shown by the unsymmetrical vibration mode of lithium ion on the basis of quantum chemical calculation of isotope effect on dehydration of hydrated lithium ion. (S.Y.)

  17. Comparison of chemical fertilizer and sewage sludge application on some nutrients’ bioavailability in three textural classes of a calcareous soil after harvesting spinach (Spinacia oleracea L.)

    OpenAIRE

    Boostani, H. R; A. Ronaghi

    2012-01-01

    Sewage sludge (SS) as a source of macro- and micro nutrients has been utilized in many countries for crop and vegetable production. To compare the influence of SS with chemical fertilizer on macro- and micro nutrients bioavailability in three textural classes of a calcareous soil after harvesting spinach (Spinacia oleracea L.), a factorial experiment was carried out in a completely randomized design with two factors and three replications under glasshouse conditions. The first factor was SS l...

  18. Elemental and thermo-chemical analysis of oil palm fronds for biomass energy conversion

    Science.gov (United States)

    Guangul, Fiseha Mekonnen; Sulaiman, Shaharin Anwar; Raghavan, Vijay R.

    2012-06-01

    Oil palm frond is the most abundant yet untapped biomass waste in Malaysia. This paper investigates the characteristics of raw oil palm fronds and its ash to evaluate its potential utilization as a biomass fuel for gasification process using single throat downdraft gasifier. The morphological nature, elemental content, proximate and ultimate analysis and calorific value were studied. Field emission scanning electron microscopy and x-ray fluorescence were used to investigate the surface morphology, elemental and mineralogical nature of oil palm frond and its ash. The results were compared with other agricultural and forestry biomass wastes. From proximate analysis volatile matter, fixed carbon and ash were found to be 83.5%, 15.2% and 1.3%, respectively on dry basis. From ultimate analysis result values of 44.58%, 4.53%, 0.71% and 0.07% for carbon, hydrogen, nitrogen and sulfur were found respectively on dry basis. Oxygen was determined by difference and found to be 48.81%. The proximate and ultimate analysis results indicate that oil palm frond is better than agricultural wastes and less than most forestry wastes to use as a feedstock in the gasification process in order to get a better quality of syngas. The amount of ash content in OPF was found to be much less than in agricultural wastes and higher than most forestry wastes. From x-ray fluorescence analysis CaO and K2O were found as the major oxides in oil palm fronds and rice husk ash with the amount of 28.46% and 15.71% respectively. The overall results of oil palm fronds were found to be satisfactory to use as a feedstock for the process of gasification.

  19. Trace element distribution in different chemical fractions of False Bay sediments

    International Nuclear Information System (INIS)

    Trace metals in the aquatic environment are generally concentrated on solid geochemical phases which eventually become incorporated into estuarine and marine sediments. The mechanism of trace metal concentration is believed to be adsorption on various geochemical phases, such as hydrous metal oxides, clays and organic matter. Metals in estuarine sediments can thus be expected to be partitioned between different phases, depending on the concentration of the phase and the strength of the adsorption bond. The bioavailability of sediment-bound metals to deposit-feeding organisms will depend on trace metal partitioning and the kinetics of biological metal uptake from each geochemical phase. The major objective of this study was to establish an analytical procedure involving sequential chemical extractions for the partitioning of particulate trace metals in sediment samples, collected from False Bay. Eight metals were examined, i.e. Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn. X-ray diffraction was also used in the study

  20. Peculiarities of cognitive functions in urban children with mental retardation in relation to the chemical elements content in a hair

    Directory of Open Access Journals (Sweden)

    Yevstafyeva E.V.

    2012-06-01

    Full Text Available

    In 30 children in the age of 12,8±0,3 with mental retardation and 30 healthy children of the same age an element balance of organism and state of cognitive functions were related. The content of elements (Ca, Fe, Mn, Mo, Ni, Sr, Pb in the hair was determined by a method of X-ray fuorescent spectroscopy. The content of Ca, Ni and Mn in 55 % of children and the defciency of Fe in 21 % of children with mental retardation were established. The defciency of Ca, Fe and Mn of healthy children was displayed. The value of Sr and Pb in organism in children of booth group was normal. The content of Mo in hair in 40 % of children with mental retardation and in 30 % of children of a check-group were established. The relationship between the content of chemical elements in organisms and state of cognitive functions was analyzed by non-parametric analysis by Spearmen. The excess of Ni in organism of children with mental retardation and defciency of Fe in organism of children in booth groups negatively infuenced the characteristics of cognitive functions (0,34of cognitive functions of Mn was not reveled.

  1. A New Class of Contrast Agents for MRI Based on Proton Chemical Exchange Dependent Saturation Transfer (CEST)

    Science.gov (United States)

    Ward, K. M.; Aletras, A. H.; Balaban, R. S.

    2000-03-01

    It has been previously shown that intrinsic metabolites can be imaged based on their water proton exchange rates using saturation transfer techniques. The goal of this study was to identify an appropriate chemical exchange site that could be developed for use as an exogenous chemical exchange dependent saturation transfer (CEST) contrast agent under physiological conditions. These agents would function by reducing the water proton signal through a chemical exchange site on the agent via saturation transfer. The ideal chemical exchange site would have a large chemical shift from water. This permits a high exchange rate without approaching the fast exchange limit at physiological pH (6.5-7.6) and temperature (37°C), as well as minimizing problems associated with magnetic field susceptibility. Numerous candidate chemicals (amino acids, sugars, nucleotides, heterocyclic ring chemicals) were evaluated in this preliminary study. Of these, barbituric acid and 5,6-dihydrouracil were more fully characterized with regard to pH, temperature, and concentration CEST effects. The best chemical exchange site found was the 5.33-ppm indole ring -NH site of 5-hydroxytryptophan. These data demonstrate that a CEST-based exogenous contrast agent for MRI is feasible.

  2. Class Vectors: Embedding representation of Document Classes

    OpenAIRE

    Sachan, Devendra Singh; Kumar, Shailesh

    2015-01-01

    Distributed representations of words and paragraphs as semantic embeddings in high dimensional data are used across a number of Natural Language Understanding tasks such as retrieval, translation, and classification. In this work, we propose "Class Vectors" - a framework for learning a vector per class in the same embedding space as the word and paragraph embeddings. Similarity between these class vectors and word vectors are used as features to classify a document to a class. In experiment o...

  3. Mechanism for the formation of elemental sulfur from aqueous sulfide in chemical and microbiological desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Steudel, R. [Technische Univ. Berlin (Germany). Inst. fuer Anorganische und Analytische Chemie

    1996-04-01

    A detailed reaction mechanism is proposed for the formation of crystalline elemental sulfur from aqueous sulfide by oxidation with transition-metal ions like V{sup 5}, Fe{sup 3}, Cu{sup 2}, etc. The first step is the formation of HS{center_dot} radicals by one-electron oxidation of HS{sup {minus}} ions. These radicals exist at pH values near 7 mainly as S{center_dot}{sup {minus}}. Their spontaneous decay results in the formation of the disulfide ion S{sub 2}{sup 2{minus}}. The further oxidation of disulfide either by S{center_dot}{sup {minus}} radicals or by the transition-metal ions yields higher polysulfide ions from which the homocyclic sulfur molecules S{sub 6}, S{sub 7}, and S{sub 8} are formed. In water these hydrophobic molecules form clusters which grow to droplets of liquid sulfur (sulfur sol). Depending on the composition of the aqueous phase, crystallization of the liquid sulfur as either {alpha}- or {beta}-S{sub 8} is rapid or delayed. Surfactants delay this solidification, while certain cations promote it. All these reactions are proposed to take place in desulfurization plants working by the Stretford, Sulfolin, Lo-Cat, SulFerox, or Bio-SR processes. In addition, the sulfur produced from sulfide by oxidizing sulfur bacteria is formed by the same mechanism, which now explains many observations made previously (including the formation of the byproducts thiosulfate, polythionates, and sulfate).

  4. Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament

    Science.gov (United States)

    Miettinen, O.

    2016-08-01

    Deeply embedded low-mass protostars can be used as testbeds to study the early formation stages of solar-type stars, and the prevailing chemistry before the formation of a planetary system. The present study aims to characterise further the physical and chemical properties of the protostellar core Orion B9-SMM3. The Atacama Pathfinder EXperiment (APEX) telescope was used to perform a follow-up molecular line survey of SMM3. The observations were done using the single pointing (frequency range 218.2-222.2 GHz) and on-the-fly mapping methods (215.1-219.1 GHz). These new data were used in conjunction with our previous data taken by the APEX and Effelsberg 100 m telescopes. The following species were identified from the frequency range 218.2-222.2 GHz: ^{13}CO, C^{18}O, SO, para-H2CO, and E1-type CH3OH. The mapping observations revealed that SMM3 is associated with a dense gas core as traced by DCO+ and p-H2CO. Altogether three different p-H2CO transitions were detected with clearly broadened linewidths (Δ v˜8.2-11 km s^{-1} in FWHM). The derived p-H2CO rotational temperature, 64±15 K, indicates the presence of warm gas. We also detected a narrow p-H2CO line (Δ v=0.42 km s^{-1}) at the systemic velocity. The p-H2CO abundance for the broad component appears to be enhanced by two orders of magnitude with respect to the narrow line value ({˜}3×10^{-9} versus {˜}2×10^{-11}). The detected methanol line shows a linewidth similar to those of the broad p-H2CO lines, which indicates their coexistence. The CO isotopologue data suggest that the CO depletion factor decreases from {˜}27±2 towards the core centre to a value of {˜}8±1 towards the core edge. In the latter position, the N2D+/N2H+ ratio is revised down to 0.14±0.06. The origin of the subfragments inside the SMM3 core we found previously can be understood in terms of the Jeans instability if non-thermal motions are taken into account. The estimated fragmentation timescale, and the derived chemical abundances

  5. Characterization, feasibility and optimization of Agaricus subrufescens growth based on chemical elements on casing layer

    Science.gov (United States)

    Cunha Zied, D.; Pardo-Giménez, A.; de Almeida Minhoni, M.T.; Villas Boas, R.L.; Alvarez-Orti, M.; Pardo-González, J.E.

    2012-01-01

    The aim of this study was to analyze yields, biological efficiency, earliness (expressed as days to first harvest), and precociousness and establish models for the mushroom growing according to these parameters. The experiment followed a double factorial design with four sources of calcium (calcitic limestone, calcitic limestone + gypsum, dolomitic limestone and dolomitic limestone + gypsum) and 2 application times (25 days before casing and at the moment of casing), with 4 replicates for each treatment. Different calcium sources influenced differently Agaricus subrufescens production, especially as regards earliness, which showed significantly higher values when dolomitic limestone with gypsum was applied. Yield and biological efficiency were negatively correlated with H + AL, organic matter and Mg amount. Furthermore, earliness was positively correlated with H + Al, organic matter, and the amount of Mg and Fe. Finally, negative correlations were observed between precociousness and the amount of Ca, SB (sum of base), CEC (cation exchange capacity) and V% (percentage of base saturation). The models presented in this work are extremely important for predicting the agronomic performance of Agaricus subrufescens on the basis of chemical analysis provided by the casing soil. PMID:23961195

  6. Element Abundances in a Gas-rich Galaxy at z = 5: Clues to the Early Chemical Enrichment of Galaxies

    CERN Document Server

    Morrison, Sean; Som, Debopam; DeMarcy, Bryan; Quiret, Samuel; Peroux, Celine

    2016-01-01

    Element abundances in high-redshift quasar absorbers offer excellent probes of the chemical enrichment of distant galaxies, and can constrain models for population III and early population II stars. Recent observations indicate that the sub-damped Lyman-alpha (sub-DLA) absorbers are more metal-rich than the damped Lyman-alpha (DLA) absorbers at redshifts 0$$4.7. However, only 3 DLAs at $z$$>$4.5 and no sub-DLAs at $z$$>$3.5 have "dust-free" metallicity measurements of undepleted elements. We report the first measurement of element abundances in a sub-DLA at $z$=5.0, using Keck HIRES and ESI data. We obtain fairly robust abundances of C, O, Si, and Fe, using lines outside the Lyman-alpha forest. We find this absorber to be metal-poor, with [O/H]=$-2.02$$\\pm$0.12, which is $>$5$\\sigma$ below the level expected from an extrapolation of the trend for $z$$<$3.5 sub-DLAs. The C/O ratio is $1.7^{+0.4}_{-0.3}$ times lower than in the Sun. More strikingly, Si/O is $3.0^{+0.6}_{-0.5}$ times lower than in the Sun, wh...

  7. Finite Volume Element Predictor-corrector Method for a Class of Nonlinear Parabolic Systems%一类非线性抛物型方程组的有限体积元预估-校正方法

    Institute of Scientific and Technical Information of China (English)

    高夫征

    2005-01-01

    A finite volume element predictor-correetor method for a class of nonlinear parabolic system of equations is presented and analyzed. Suboptimal L2 error estimate for the finite volume element predictor-corrector method is derived. A numerical experiment shows that the numerical results are consistent with theoretical analysis.

  8. Adaptive finite element method assisted by stochastic simulation of chemical systems

    Czech Academy of Sciences Publication Activity Database

    Cotter, S.L.; Vejchodský, Tomáš; Erban, R.

    2013-01-01

    Roč. 35, č. 1 (2013), B107-B131. ISSN 1064-8275 R&D Projects: GA AV ČR(CZ) IAA100190803 Institutional support: RVO:67985840 Keywords : chemical Fokker-Planck * adaptive meshes * stochastic simulation algorithm Subject RIV: BA - General Mathematics Impact factor: 1.940, year: 2013 http://epubs.siam.org/doi/abs/10.1137/120877374

  9. csrT Represents a New Class of csrA-Like Regulatory Genes Associated with Integrative Conjugative Elements of Legionella pneumophila

    Science.gov (United States)

    Abbott, Zachary D.; Flynn, Kaitlin J.; Byrne, Brenda G.; Mukherjee, Sampriti; Kearns, Daniel B.

    2015-01-01

    ABSTRACT Bacterial evolution is accelerated by mobile genetic elements. To spread horizontally and to benefit the recipient bacteria, genes encoded on these elements must be properly regulated. Among the legionellae are multiple integrative conjugative elements (ICEs) that each encode a paralog of the broadly conserved regulator csrA. Using bioinformatic analyses, we deduced that specific csrA paralogs are coinherited with particular lineages of the type IV secretion system that mediates horizontal spread of its ICE, suggesting a conserved regulatory interaction. As a first step to investigate the contribution of csrA regulators to this class of mobile genetic elements, we analyzed here the activity of the csrA paralog encoded on Legionella pneumophila ICE-βox. Deletion of this gene, which we name csrT, had no observed effect under laboratory conditions. However, ectopic expression of csrT abrogated the protection to hydrogen peroxide and macrophage degradation that ICE-βox confers to L. pneumophila. When ectopically expressed, csrT also repressed L. pneumophila flagellin production and motility, a function similar to the core genome's canonical csrA. Moreover, csrT restored the repression of motility to csrA mutants of Bacillus subtilis, a finding consistent with the predicted function of CsrT as an mRNA binding protein. Since all known ICEs of legionellae encode coinherited csrA-type IV secretion system pairs, we postulate that CsrA superfamily proteins regulate ICE activity to increase their horizontal spread, thereby expanding L. pneumophila versatility. IMPORTANCE ICEs are mobile DNA elements whose type IV secretion machineries mediate spread among bacterial populations. All surveyed ICEs within the Legionella genus also carry paralogs of the essential life cycle regulator csrA. It is striking that the csrA loci could be classified into distinct families based on either their sequence or the subtype of the adjacent type IV secretion system locus. To

  10. QUANTITY DETERMINATION OF MOLYBDENUM FROM PISUM SATIVUM PLANTS AND THE INFLUENCE OF HEAVY METAL TO CHEMICAL ELEMENTS ACCUMULATION

    Directory of Open Access Journals (Sweden)

    MONICA BUTNARIU

    2013-12-01

    Full Text Available The aim of this study was to test the pea plant as sentinel specie for the heavy metal molybdenum. Evaluation of soil quality after the molybdenum uptake by pea revealed the following results: Pea plant is a bioindicator that concentrates molybdenum with fast reaction to increasing concentrations in soil. Molybdenum had a positive effect concerning the plant growth (throughout all experimental process, pea plants treated with highest concentrated metal solution reached the largest dimensions. Accumulated molybdenum was directly proportional to increasing concentration of the applied solution to roots, stem, leaves and flowers of the experimental plants; however it resided in flowerpot soil too .In the leguminous roots where the nitroreductase and nitrogenese activity is increased, molybdenum content was much higher compared to the aerial parts of the plant. All the way through molybdenum accumulation in the experimental plants up to high concentrations, other chemical elements revealed lower concentration although within the normal limits, with the exception of phosphorus. These plants were found to assimilate high molybdenum quantities without any detrimental consequences for them since molybdenum accumulation occurred in vacuoles in innocuous chemical forms.

  11. Metal free earth abundant elemental red phosphorus: a new class of visible light photocatalyst and photoelectrode materials.

    Science.gov (United States)

    Ansari, Sajid Ali; Ansari, Mohammad Shahnawaze; Cho, Moo Hwan

    2016-02-01

    Developing a high-performance photocatalyst and a photoelectrode with enhanced visible light harvesting properties is essential for practical visible light photocatalytic applications. Noble metal-free, highly visible light-active, elemental red phosphorus (RP) was prepared by a facile mechanical ball milling method, which is a reproducible, low cost and controllable synthesis process. The synthesis used inexpensive and abundant raw materials because most RP hybrids are based on expensive noble-metals. The novel milled RP showed significantly enhanced photocatalytic and photoelectrochemical performances with a lower charge transfer resistance compared to commercial RP under wide visible photoirradiation, making it a feasible alternative for photocatalytic applications. PMID:26765211

  12. Investigation of Chemical and Physical Changes to Bioapatite During Fossilization Using Trace Element Geochemistry, Infrared Spectroscopy and Stable Isotopes

    Science.gov (United States)

    Suarez, C. A.; Kohn, M. J.

    2013-12-01

    Bioapatite in the form of vertebrate bone can be used for a wide variety of paleo-proxies, from determination of ancient diet to the isotopic composition of meteoric water. Bioapatite alteration during diagenesis is a constant barrier to the use of fossil bone as a paleo-proxy. To elucidate the physical and chemical alteration of bone apatite during fossilization, we analyzed an assortment of fossil bones of different ages for trace elements, using LA-ICP-MS, stable isotopes, and reflected IR spectroscopy. One set of fossil bones from the Pleistocene of Idaho show a diffusion recrystallization profile, however, rare earth element (REE) profiles indicate diffusion adsorption. This suggests that REE diffusion is controlled by changing (namely decreasing) boundary conditions (i.e. decreasing concentration of REE in surrounding pore fluids). Reflected IR analysis along this concentration profile reveal that areas high in U have lost type A carbonate from the crystal structure in addition to water and organics. Stable isotopic analysis of carbon and oxygen will determine what, if any, change in the isotopic composition of the carbonate component of apatite has occurred do to the diffusion and recrystallization process. Analysis of much older bone from the Cretaceous of China reveal shallow REE and U concentration profiles and very uniform reflected IR spectra with a significant loss of type A carbonate throughout the entire bone cortex. Analysis of stable isotopes through the bone cortex will be compared to the stable isotopes collected from the Pleistocene of Idaho.

  13. Slaughter and carcass characteristics, chemical composition and physical properties of longissimus lumborum muscle of heifers as related to marbling class

    OpenAIRE

    A. Oler; B. Głowińska; Młynek, K.

    2015-01-01

    The experiment involved 68 heifers obtained from Polish Black-and-White Lowland dams (with no more than 50% Holstein Friesian blood) sired by Limousin bulls. The study was arranged to determine the slaughter and carcass traits, chemical composition and physical properties of musculus longissimus lumborum (MLL) as related to the level of marbling, and to examine the correlation between some of the traits mentioned above and the culinary characteristics of meat. The results of...

  14. chemical studies on the reactivity of some organic extractants for extraction and separation of certain elements from aqueous solutions

    International Nuclear Information System (INIS)

    Lanthanide elements such as lanthanum and neodymium are important elements in photo-electronic and metallurgical industries as well as in nuclear technology. The main constituents of the spent nuclear fuel are actinides like uranium, thorium and various fission products including lanthanides. The co-ordination compounds of the trivalent lanthanum and neodymium continues to be an active research area, which includes the specific spectroscopic and magnetic properties of rare earth ions and their applications as super molecular device, contrast-enhancing agents in magnetic resonance imaging, optical signal amplifiers and electroluminescent (EL) devices. Hence, the separation and purification of these elements is of great concern. Solvent extraction technique is employed to separate and purify rare earth elements in an industrial scale, but the separation of lanthanum and neodymium is a difficult task, as lanthanide ions exhibit similar chemical and physical properties. They have generally common and stable +3 oxidation state that requires synthesis of certain extractants which are able to extract them from different aqueous solutions. During the last twenty years, different publications have pointed out the remarkable properties of alkyl amide in the field of separation chemistry. These extractants are able to form stable co-ordination compounds with different metallic ions. In this concern, this thesis deals with the synthesis of different amide extractants namely N, N diethylacetoamide (DEAA), N, N Teteraphenyl malonamide (TPMA), N, N diphenylbenzamide (DPBA), N, N' diphenylacetoamide (DPAA), and N, N' Teteraethyl malonamide (TEMA), which were synthesized, characterized and compared with Aliquat-336 in kerosene for extraction and separation of La (III) and Nd (III). The effect of the different parameters affecting the extraction of these metals from aqueous nitric acid medium in the different systems has been studied in terms of shaking time, nitric acid, hydrogen

  15. PROGNOSTIC VALUE OF SOME CHEMICAL ELEMENTS IN THE ORAL FLUID OF PEOPLEWHO USE REMOVABLE DENTURES IN THE PROCESS OF STONE FORMATION

    OpenAIRE

    Mikhaylenko, T. N.; Rozhko, M. M.; Ersteniuk, H. M.

    2015-01-01

    This work confirms a multifactorial effect on stone formation processes in the oral cavity of persons who use removable dentures, including an important role of macro- and micronutrients, namely, calcium, phosphorus, magnesium and zinc. The study of these elements was conducted in oral fluid and dental deposits and removable denture bases. Correlations between the level of oral hygiene and contents of chemical elements in oral fluid of people with removable dentures were found. With the incre...

  16. Proceedings of transuranium elements

    International Nuclear Information System (INIS)

    The identification of the first synthetic elements was established by chemical evidence. Conclusive proof of the synthesis of the first artificial element, technetium, was published in 1937 by Perrier and Segre. An essential aspect of their achievement was the prediction of the chemical properties of element 43, which had been missing from the periodic table and which was expected to have properties similar to those of manganese and rhenium. The discovery of other artificial elements, astatine and francium, was facilitated in 1939-1940 by the prediction of their chemical properties. A little more than 50 years ago, in the spring of 1940, Edwin McMillan and Philip Abelson synthesized element 93, neptunium, and confirmed its uniqueness by chemical means. On August 30, 1940, Glenn Seaborg, Arthur Wahl, and the late Joseph Kennedy began their neutron irradiations of uranium nitrate hexahydrate. A few months later they synthesized element 94, later named plutonium, by observing the alpha particles emitted from uranium oxide targets that had been bombarded with deuterons. Shortly thereafter they proved that is was the second transuranium element by establishing its unique oxidation-reduction behavior. The symposium honored the scientists and engineers whose vision and dedication led to the discovery of the transuranium elements and to the understanding of the influence of 5f electrons on their electronic structure and bonding. This volume represents a record of papers presented at the symposium

  17. Consideration on thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 1: Tc, U, Am

    International Nuclear Information System (INIS)

    The solubility determines the release of radionuclides from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Complexations of radionuclides by ligands in groundwater affect the interaction between radionuclides and geologic media, thus affect their migration behavior. Thermodynamic data for Tc, Am and U were reviewed and compiled to be used for predicting the solubility and chemical species in groundwater. Thermodynamic data were reviewed with emphasis on the hydrolysis and carbonate complexation that can dominate the speciation in typical groundwater. Thermodynamic data for other species were selected based on existing database. Thermodynamic data for other important elements are under investigation, thus shown in an appendix for temporary use. (author)

  18. Consideration on thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 1: Tc, U, Am

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Tetsuji; Takeda, Seiji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-01-01

    The solubility determines the release of radionuclides from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Complexations of radionuclides by ligands in groundwater affect the interaction between radionuclides and geologic media, thus affect their migration behavior. Thermodynamic data for Tc, Am and U were reviewed and compiled to be used for predicting the solubility and chemical species in groundwater. Thermodynamic data were reviewed with emphasis on the hydrolysis and carbonate complexation that can dominate the speciation in typical groundwater. Thermodynamic data for other species were selected based on existing database. Thermodynamic data for other important elements are under investigation, thus shown in an appendix for temporary use. (author)

  19. Bragg grating chemical sensor with hydrogel as sensitive element

    Institute of Scientific and Technical Information of China (English)

    Xiaomei Liu(刘小梅); Shilie Zheng(郑史烈); Xianmin Zhang(章献民); Jun Cong(丛军); Kangsheng Chen(陈抗生); Jian Xu(徐坚)

    2004-01-01

    A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hydrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor.

  20. Structural evaluation method for class 1 vessels by using elastic-plastic finite element analysis in code case of JSME rules on design and construction

    International Nuclear Information System (INIS)

    A structural evaluation method by using elastic-plastic finite element analysis has been developed and published as a code case of Rules on Design and Construction for Nuclear Power Plants (The First Part: Light Water Reactor Structural Design Standard) in the JSME Codes for Nuclear Power Generation Facilities. Its title is 'Alternative Structural Evaluation Criteria for Class 1 Vessels Based on Elastic-Plastic Finite Element Analysis' (NC-CC-005). This code case applies elastic-plastic analysis to evaluation of such failure modes as plastic collapse, thermal ratchet, fatigue and so on. Advantage of this evaluation method is free from stress classification, consistently use of Mises stress and applicability to complex 3-dimensional structures which are hard to be treated by the conventional stress classification method. The evaluation method for plastic collapse has such variation as the Lower Bound Approach Method, Twice-Elastic-Slope Method and Elastic Compensation Method. Cyclic Yield Area (CYA) based on elastic analysis is applied to screening evaluation of thermal ratchet instead of secondary stress evaluation, and elastic-plastic analysis is performed when the CYA screening criteria is not satisfied. Strain concentration factors can be directly calculated based on elastic-plastic analysis. (author)

  1. PHYSIC AND CHEMICAL BASIS FOR THE INVOLVEMENT OF D-ELEMENTS OF THE FOURTH GROUP (TITANIUM, ZIRCONIUM, HAFNIUM IN THE SYNTHESIS OF BUILDING AND SILICATE MATERIALS

    Directory of Open Access Journals (Sweden)

    V. I. Bolshakov

    2007-11-01

    Full Text Available In the paper the studies of physico-chemical grounds of involving the fourth group elements (titanium, zirconium, hafnium for syntheses of construction silicate materials are presented. The physico-chemical approach proposed allows involving the great group of technogenic titanium-containing semi-products, concentrates, slags and slimes for production of construction silicate materials and manufacture the products and building structures.

  2. Burst and Principal Components Analyses of MEA Data for 16 Chemicals Describe at Least Three Effects Classes.

    Science.gov (United States)

    Microelectrode arrays (MEAs) detect drug and chemical induced changes in neuronal network function and have been used for neurotoxicity screening. As a proof-•of-concept, the current study assessed the utility of analytical "fingerprinting" using Principal Components Analysis (P...

  3. Elemental diffusion during the droplet epitaxy growth of In(Ga)As/GaAs(001) quantum dots by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. B.; Chen, B.; Wang, Y. B.; Liao, X. Z., E-mail: xiaozhou.liao@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Lei, W. [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth, WA 6009 (Australia); Tan, H. H.; Jagadish, C. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Zou, J. [Materials Engineering and Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072 (Australia); Ringer, S. P. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia)

    2014-01-13

    Droplet epitaxy is an important method to produce epitaxial semiconductor quantum dots (QDs). Droplet epitaxy of III-V QDs comprises group III elemental droplet deposition and the droplet crystallization through the introduction of group V elements. Here, we report that, in the droplet epitaxy of InAs/GaAs(001) QDs using metal-organic chemical vapor deposition, significant elemental diffusion from the substrate to In droplets occurs, resulting in the formation of In(Ga)As crystals, before As flux is provided. The supply of As flux suppresses the further elemental diffusion from the substrate and promotes surface migration, leading to large island formation with a low island density.

  4. Elemental diffusion during the droplet epitaxy growth of In(Ga)As/GaAs(001) quantum dots by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Droplet epitaxy is an important method to produce epitaxial semiconductor quantum dots (QDs). Droplet epitaxy of III-V QDs comprises group III elemental droplet deposition and the droplet crystallization through the introduction of group V elements. Here, we report that, in the droplet epitaxy of InAs/GaAs(001) QDs using metal-organic chemical vapor deposition, significant elemental diffusion from the substrate to In droplets occurs, resulting in the formation of In(Ga)As crystals, before As flux is provided. The supply of As flux suppresses the further elemental diffusion from the substrate and promotes surface migration, leading to large island formation with a low island density

  5. Calculation and Interpretation of the Standard Chemical Exergies of Elements Using the Chemical Reference Species%使用化学参考物质计算和阐明元素的标准化学放射本能

    Institute of Scientific and Technical Information of China (English)

    B(I)LGEN Sel(c)uk

    2009-01-01

    Exergy is the amount of work obtainable when some matter is brought to a state of thermodynamic equilibrium with the common components of the natural surroundings by means of reversible processes, involving interaction only with the above mentioned components of nature. This paper presents standard chemical exergy values for 85 elements. Reference species in the atmosphere (air), dissolved in the hydrosphere (oceans), and contained in the lithosphere (minerals) are used for these calculations. Standard chemical exergy values of elements were calculated from tabulated values obtained for standard conditions (an ambient temperature of 298.15 K and an atmospheric pressure of 0.1 MPa). Very low concentrations of elements in the atmosphere and oceans and the abundance of elements in the Earth's crust are no longer used in determining reference states for chemical elements. Liquid and gas mixtures generally are not useful as reference states. As a result of the work in this paper, a table of the chemical exergy values of many elements in the periodic table under standard conditions was tabulated.

  6. ACCUMULATION OF CHEMICAL ELEMENTS BY ORGANS OF SPARGANIUM ERECTUM L. AND THEIR POTENTIAL USE IN PHYTOREMEDIATION PROCESS

    Directory of Open Access Journals (Sweden)

    Agnieszka Edyta Parzych

    2016-01-01

    Full Text Available The study of bottom sediments and organs of Sparganium erectum carried out in the summer of 2014 in the city of Lębork, located in Northern Poland. The aim of this study was to evaluate the content of macroelements and heavy metals in the leaves, rhizomes and roots S. erectum and in bottom sediments of the Łeba River as well as comparison of accumulation and translocation factors of N, P, K, Mg, Ca, Zn, Ni, Cu, Mn, Fe, Cd and Cr in researched organs of aquatic plant. The use of S. erectum for biomonitoring and phytoremediation has also been considered. The results of Mann Whitney U test showed a number of statistically significant differences in the content of chemical elements in the leaves, rhizomes, roots and in bottom sediments. The macroelements are mainly accumulated in leaves and heavy metals are accumulated in roots and rhizomes of S. erectum. Increased Mn and Fe content in roots and rhizomes of S. erectum, in relation this physiological needs, refers to the beneficial effects of this species in the water treatment and sludge from the bottom sediment of manganese and iron compounds. The obtained bioconcentration and translocation factors values allowed to state that S. erectum can be used for phytoremediation of contaminated bottom sediments because retains metals in their roots and limit Mn and Fe mobility from roots and rhizomes to leaves once absorbed by roots of plant.

  7. Computer modelling of the chemical speciation of lanthanide and actinide elements in the human gastrointestinal tract

    International Nuclear Information System (INIS)

    Joint expert speciation system (JESS) computer modelling is used to produce biokinetic models of the gastrointestinal tract, for the radiation dose from internally deposited radionuclides to be calculated. Preliminary estimations of the interactions of Gd and Cm with all the metal binding species present in the small intestine, i.e. bile and pancreatic fluid, over a pH range of pH 5.0-9.0, have been made. The development of the models and these initial validation results for the use of Gd as a surrogate for Cm, will be presented and discussed. From these aqueous studies it appears that the use of Gd as a surrogate for Cm in bile or pancreatic fluid is doubtful. However, further speciation modelling, incorporating solids, is in process to confirm these findings. (orig.)

  8. Comparison of important nutrients/ elements and chemical/ microbiological contaminants in different types of meat

    International Nuclear Information System (INIS)

    Studies were conducted to see the levels of important nutrients and selected essential/toxic metals in different types of meat i.e. beef, poultry, mutton and fish. The meat samples were also analyzed for bacterial contamination. Highest value of protein (20.32 +- 1.86% was detected in poultry (chicken) while maximum fats and fiber contents (13.50 +- 0.14 and 0.135 +- 0.112%) were found in beef samples. The Pb content was found to be 7.0 +- 0.61 (mutton), 6.6 +- 0.58 (beef) and 3.3 +- 0.39 ppm (poultry). The highest level of Cd was determined in poultry (1.00 +- 0.13) followed by mutton (0.80 +- 0.07), beef (0.70 +- 0.08) and fish (0.25 +- 0.04 ppm). The maximum level of Cu (10.0 +- 0.55 and 7.0 +- 0.43 ppm) was detected in beef and mutton respectively while comparatively low Cu content was found in poultry as well as fish samples. It was observed that fresh meat had low levels of heavy metals. Highest concentrations of Fe (3.29 +- 0.41ppm) and P (167.8 +- 10.31) were found in mutton and beef respectively. The data revealed that majority of meat samples were also contaminated with bacteria and showed presence of E. coli. Hence, were considered unfit for human consumption. In addition % moisture and ash were also examined. The results were compared with recommended daily allowances and some remedial measures to control environmental pollution of meat sold in the open air are suggested. (author)

  9. Evaluation of some chemical analysis of granite rocks for rare elements (Tungsten, Nobuim, Tin, Tantalum)

    International Nuclear Information System (INIS)

    In this study, granite rocks samples were collected from Jebel Nikrab, in the eastern Sudan. A total of 16 samples were analyzed for Fe2O3, Mg O, CaO, Na2O, K2O and MnO2, using the atomic absorption spectrometer (AAS) and SiO2 Al2O3 using colorimeter. By classical methods analyzed for W, Ta, Nb and Sn, and all these results compared with the results have been done in the international laboratories give the same results even the results of SiO2, Al2O3, Ca O, MnO, Fe2O3, Mg O, K2O and Na2O. The range of W (0.0001-0.0005), Sn (0.00010.0024), Ta (0.003-0.0042), Nb (0.007-0.05). The range of oxide of Mn (0.07-0.1), Fe (0.17-17), Mg (0,009-0.3), Ca (0.05-1.2), Na (0.07-4.29) and K (0.02-3.7). (Author)

  10. On the Ritt order and type of a certain class of functions defined by BE-Dirichletian elements

    OpenAIRE

    Marcel Berland

    1999-01-01

    We introduce the notions of Ritt order and type to functions defined by the series ∑n=1∞fn(Ã+iÄ0)exp(−sλn),      s=Ã+iÄ,(Ã,Ä)∈R×R                                            (*) indexed by Ä0 on R, where (ÃŽÂ...

  11. Search for new chemical elements and possibilities to synthesize transactinide isotopes for chemical studies

    International Nuclear Information System (INIS)

    Elements up to Z=112 as well as 114 and 116 are officially recognized as discovered and have been named. The current literature contains reports about the synthesis of all elements up to Z=118, meaning that more than 10% of all elements are members of the transactinide series with Z=104-118. Therefore, search experiments for the new elements with Z=119 and Z=120 have been performed. An important question for such experiments concerns the optimum choice of the nuclear reaction. While only one experiment has been conducted so far with the aim of discovering Z=119, already four experiments on the synthesis of Z=120 have been performed, all employing different reactions. Still, Z=119 and 120 are not yet announced as discovered. The situation using the TASCA experiments as an example and the perspectives for the discovery of new elements are studied. The optimum reactions leading to the relatively long-lived isotopes of the transactinides as they are frequently used in chemical studies of these elements, including elements which were not studied chemically to date are discussed

  12. Effects of increasing hydrophobicity on the physical-chemical and biological properties of a class A amphipathic helical peptide.

    Science.gov (United States)

    Datta, G; Chaddha, M; Hama, S; Navab, M; Fogelman, A M; Garber, D W; Mishra, V K; Epand, R M; Epand, R F; Lund-Katz, S; Phillips, M C; Segrest, J P; Anantharamaiah, G M

    2001-07-01

    We have recently shown that a class A amphipathic peptide 5F with increased amphipathicity protected mice from diet-induced atherosclerosis (Garber et al. J. Lipid Res. 2001. 42: 545-552). We have now examined the effects of increasing the hydrophobicity of a series of homologous class A amphipathic peptides, including 5F, on physical and functional properties related to atherosclerosis inhibition by systematically replacing existing nonpolar amino acids with phenylalanine. The peptides, based on the sequence Ac-D-W-L-K-A-F-Y-D-K-V-A-E-K-L-K-E-A-F-NH(2) (Ac-18A-NH(2) or 2F) were: 3F(3)(Ac-F(3)18A-NH(2)), 3F(14)(Ac-F(14)18A-NH(2)), 4F(Ac-F(3,14)18A-NH(2)), 5F(Ac-F(11,14,17) 18A-NH(2)), 6F(Ac-F(10,11,14,17)18A-NH(2)), and 7F(Ac-F(3,10,11,14,17) 18A-NH(2)). Measurements of aqueous solubility, HPLC retention time, exclusion pressure for penetration into an egg phosphatidylcholine (EPC) monolayer, and rates of EPC solubilization revealed an abrupt increase in the hydrophobicity between peptides 4F and 5F; this was accompanied by increased ability to associate with phospholipids. The peptides 6F and 7F were less effective, indicating a limit to increased hydrophobicity for promoting lipid interaction in these peptides. Despite this marked increase in lipid affinity, these peptides were less effective than apoA-I in activating the plasma enzyme, lecithin:cholesterol acyltransferase, with 5F activating LCAT the best (80% of apoA-I). Peptides 4F, 5F, and 6F were equally potent in inhibiting LDL-induced monocyte chemotactic activity. These studies suggest that an appropriate balance between peptide-peptide and peptide-lipid interactions is required for optimal biological activity of amphipathic peptides. These studies provide a rationale for the design of small apoA-I-mimetics with increased potency for atherosclerosis inhibition. PMID:11441137

  13. Does the Chemical Diversity of the Order Haplosclerida (Phylum Porifera: Class Demospongia) Fit with Current Taxonomic Classification?

    Science.gov (United States)

    Tribalat, Marie-Aude; Marra, Maria V; McCormack, Grace P; Thomas, Olivier P

    2016-06-01

    Sponges and their associated microbiota are well known to produce a large diversity of natural products, also called specialized metabolites. In addition to their potential use in the pharmaceutical industry, these rather species-specific compounds may help in the classification of some particular sponge groups. We review herein compounds isolated from haplosclerid sponges (Class Demospongia, Order Haplosclerida) in order to help in the revision of this large group of marine invertebrates. We focus only on 3-alkylpyridine derivatives and polyacetylenic compounds, as these two groups of natural products are characteristic of haplosclerid species and are highly diverse. A close collaboration between chemists and biologists is required in order to fully apply chemotaxonomical approaches, and whenever possible biological data should include morphological and molecular data and some insight into their microbial abundance. PMID:27135628

  14. The effect of rotation on the abundances of the chemical elements of the A-type stars in the Praesepe cluster

    Science.gov (United States)

    Fossati, L.; Bagnulo, S.; Landstreet, J.; Wade, G.; Kochukhov, O.; Monier, R.; Weiss, W.; Gebran, M.

    2008-06-01

    Aims: We study how chemical abundances of late B-, A-, and early F-type stars evolve with time, and we search for correlations between the abundance of chemical elements and other stellar parameters, such as effective temperature and υ sin i. Methods: We observed a large number of B-, A-, and F-type stars belonging to open clusters of different ages. In this paper we concentrate on the Praesepe cluster (log t = 8.85), for which we have obtained high-resolution, high signal-to-noise ratio spectra of sixteen normal A- and F-type stars and one Am star, using the SOPHIE spectrograph of the Observatoire de Haute-Provence. For all the observed stars, we derived fundamental parameters and chemical abundances. In addition, we discuss another eight Am stars belonging to the same cluster, for which the abundance analysis had been presented in a previous paper. Results: We find a strong correlation between the peculiarity of Am stars and υ sin i. The abundance of the elements underabundant in Am stars increases with υ sin i, while it decreases for the overabundant elements. Chemical abundances of various elements appear correlated with the iron abundance. Based on observations made at the Observatoire de Haute-Provence. Figures [see full textsee full textsee full text] to [see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  15. ELEMENTAL ABUNDANCES AND THEIR IMPLICATIONS FOR THE CHEMICAL ENRICHMENT OF THE BOOeTES I ULTRAFAINT GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Gerard [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Norris, John E.; Yong, David [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia); Monaco, Lorenzo [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago 19 (Chile); Wyse, Rosemary F. G. [Department of Physics and Astronomy, The Johns Hopkins University, 3900 North Charles Street, Baltimore, MD 21218 (United States); Geisler, D., E-mail: gil@ast.cam.ac.uk, E-mail: jen@mso.anu.edu.au, E-mail: yong@mso.anu.edu.au, E-mail: lmonaco@eso.org, E-mail: wyse@pha.jhu.edu, E-mail: dgeisler@astro-udec.cl [Departamento de Astronomia, Universidad de Concepcion (Chile)

    2013-01-20

    We present a double-blind analysis of high-dispersion spectra of seven red giant members of the Booetes I ultrafaint dwarf spheroidal galaxy, complemented with re-analysis of a similar spectrum of an eighth-member star. The stars cover [Fe/H] from -3.7 to -1.9 and include a CEMP-no star with [Fe/H] = -3.33. We conclude from our chemical abundance data that Booetes I has evolved as a self-enriching star-forming system, from essentially primordial initial abundances. This allows us uniquely to investigate the place of CEMP-no stars in a chemically evolving system, in addition to limiting the timescale of star formation. The elemental abundances are formally consistent with a halo-like distribution, with enhanced mean [{alpha}/Fe] and small scatter about the mean. This is in accord with the high-mass stellar initial mass function in this low-stellar-density, low-metallicity system being indistinguishable from the present-day solar neighborhood value. There is a non-significant hint of a decline in [{alpha}/Fe] with [Fe/H]; together with the low scatter, this requires low star formation rates, allowing time for supernova ejecta to be mixed over the large spatial scales of interest. One star has very high [Ti/Fe], but we do not confirm a previously published high value of [Mg/Fe] for another star. We discuss the existence of CEMP-no stars, and the absence of any stars with lower CEMP-no enhancements at higher [Fe/H], a situation that is consistent with knowledge of CEMP-no stars in the Galactic field. We show that this observation requires there be two enrichment paths at very low metallicities: CEMP-no and 'carbon-normal'.

  16. Application of chemical fractionation for monitoring some trace elements in street and industrial dust from Wadmedani, Sudan

    International Nuclear Information System (INIS)

    This study monitors some trace elements concentration in street and industrial dust from Wad Medani city, Gezira State in central Sudan. A total of 20 samples of dust were collected from crowded and non-crowded streets, material processing workshop and a tannery. Samples were treated by sequential chemical extraction in five fractions, which termed as exchangeable fraction, carbonate fraction, Fe-Mn oxides fraction, organic matter fraction and residual fraction. The same samples were digested by wet method. The obtained solutions were analyzed for Cr, Fe, Ni, Cu, Zn, and Pb content using Atomic Absorption Spectrometer (AAS) and for Na and K content using Flame Emission Spectrometer (FES). X-Ray Fluorescence Spectrometer (XRF) was used to determine the total content of Na, K, Cr, Fe, Ni, Cu, Zn and Pb in the bulk sample. Results of total content, which obtained by AAS, FES and XRF spectrometry, were compared with each other and with total content for the fractionated samples. Certified reference materials from IAEA were analyzed to make sure of the data obtained. The ranges of concentrations obtained are 113-3900 μg/g for Cr, 0.3-110.4 mg/g for Fe, 27-500 μg/g for Ni, 34.7-4390 μ/g for Cu, 62-1320 μg/g for Zn and 40-1250 μg/g for Pb dry weight. The obtained results were analyzed statistically using multivariate methods that include Correlation Matrices, Principal Component Analysis (PCA) and cluster analysis. The concentrations of trace elements in street and industrial dust of Wad Medani were compared with those values in literature. It has been observed that the dust from street and industrial area of wad Medani is slightly affected by anthropogenic sources.(Author)

  17. The partition behavior and the chemical speciation of selected trace elements in a typical coal sample during pyrolysis / Tivo Bafana Hlatshwayo

    OpenAIRE

    Hlatshwayo, Tivo Bafana

    2008-01-01

    Sasol is by far the world's leading company in upgrading of low-grade coal into high value chemicals and fuels. Such plants also utilise fine particles or pulverised coal in the combustion process to generate steam and electricity for their processes. Certain trace elements released from coal during utilisation may be of environmental concern. From the literature findings it appears that the elements of interest are mercury, arsenic and selenium due to their potential health hazard and as...

  18. The effects of music, relaxation and other suggesto- 24 pedic elements in a primary school German class. An experimental investigation

    OpenAIRE

    Uschi Felix

    2013-01-01

    This nine week study set out to test whether, in addition to good communicative teaching, music, relaxation, suggestion, and the adoption by the students of German personalities, would have a positive effect on students' language self-concept, attitude and achievement. The subjects were twenty-eight fourth and fifth year students (average age nine years eight months).at a metropolitan Catholic Primary School in South Australia. Pairs of students were matched for sex, year level and language s...

  19. Physical-chemical studies of transuranium elements. Progress report, April 1, 1983-March 31, 1984

    International Nuclear Information System (INIS)

    The report is divided into six sections: spectroscopic and electrochemical studies of Np and Pu in carbonate solutions, delocalization of 5f electrons in Bk and Cf metals under pressure, spectra of lanthanides and actinides in DMSO2, relativistic multiple scattering calculations for metal complexes containing heavy atoms, L x rays in Bk and Cf metals, and solution calorimetry of Bk oxides

  20. Solvent extraction for the chemical separations of the 5f elements

    International Nuclear Information System (INIS)

    After a brief account of the needs in actinides new extractants, the interest of N,N-dialkylamides and N,N'-tetraalkyles malonamides is shown. Results dealing mainly with the properties of N,N-dialkylamides as TBP alternate in irradiated fuel reprocessing are presented. They are: the selection of amides of which the uranyle nitrato adducts are soluble in alkanes; the extraction of: U(VI), Pu(IV) and fission products; the radiolytic and hydrolytic stability of amides and a bench scale test of N,N-di (2-ethylhexyl) hexanamide in a first reprocessing cycle. The N,N'-tetra or pentaalkyl malonamides extractive properties are described. They indicate that these completely incinerable extractants are very promising for the actinides recovery from the radioactive wastes. The needs in basic researches which lead to a best understanding of the actinides extraction chemistry are illustrated by some examples. 26 refs

  1. Chemistry of superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Schaedel, M. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan). Advanced Science Research Center; GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany)

    2012-07-01

    The chemistry of superheavy elements - or transactinides from their position in the Periodic Table - is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ('pre-separator') are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table. (orig.)

  2. Chemistry of superheavy elements

    International Nuclear Information System (INIS)

    The chemistry of superheavy elements - or transactinides from their position in the Periodic Table - is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ('pre-separator') are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table. (orig.)

  3. Characterization, feasibility and optimization of Agaricus subrufescens growth based on chemical elements on casing layer

    OpenAIRE

    Cunha Zied, D.; Pardo-Giménez, A.; de Almeida Minhoni, M.T.; R.L. Villas Boas; Alvarez-Orti, M.; Pardo-González, J.E.

    2012-01-01

    The aim of this study was to analyze yields, biological efficiency, earliness (expressed as days to first harvest), and precociousness and establish models for the mushroom growing according to these parameters. The experiment followed a double factorial design with four sources of calcium (calcitic limestone, calcitic limestone + gypsum, dolomitic limestone and dolomitic limestone + gypsum) and 2 application times (25 days before casing and at the moment of casing), with 4 replicates for eac...

  4. Research on separation and extraction technology of the light element isotopes by the chemical exchange process

    International Nuclear Information System (INIS)

    It was clarified that the separation coefficient became 1.036, and succeeded in the development of the new, efficient lithium separator (Sodium Super-Ionic Conductor: NASICON) which is the elution liquid in the acid processed phosphate system for the lithium isotope separation technology. NASICON can be used in the column for the isotope separation, repeatedly if the nitric acid is used for the elution liquid and the hydroxide lithium or the acetic acid lithium solution as an adsorption solution of the lithium. Furthermore, the separation coefficient of 1.029 was obtained using the glucamine resin of the ester system for the boron isotope separation technology. (H. Katsuta)

  5. Properties of elements

    International Nuclear Information System (INIS)

    An element, in its chemical definition, is a common entity to the different variants of a simple substance and to the combinations of this substance with others. The place of an element in the periodic system is indicated by its atomic number (number of protons of the nucleus). The isotopes of a same element differ by the number of neutrons. Ninety-three elements exist naturally and 20 others have been produced artificially. This article presents the main properties of the elements summarized in tables: general properties (atomic number, name, symbol, atomic mass, electronic structure, first ionization energy, electronic affinity, oxidation number, density, fusion and boiling temperatures), the atomic and metallic radii, the electronegativity, the atomic mass and period of the main radionuclides, the historical discovery of the elements and their relative abundance on the Earth. (J.S.)

  6. Chemical elements in invertebrate orders for environmental quality studies

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcelo R.L.; Franca, Elvis J.; Paiva, Jose D.S.; Hazin, Clovis A., E-mail: marcelo_rlm@hotmail.com, E-mail: ejfranca@cnen.gov.br, E-mail: dan-paiva@hotmail.com, E-mail: chazin@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Fonseca, Felipe Y.; Fernandes, Elisabete A. de Nadai; Bacchi, Marcio A., E-mail: felipe-yamada@hotmail.com, E-mail: lis@cena.usp.br, E-mail: mabacchi@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-07-01

    Among the biomonitors of environmental quality, there is a lack of studies on using invertebrates to evaluate quantitatively chemical elements in ecosystems. This group of animals is quite numerous, widely distributed and adaptable to the most diverse environmental conditions. These features are very useful for the environmental quality assessment, as well as the several occurring insect-plant interactions performing essential functions in ecosystems. The objective of this work is to study the variability of chemical composition of invertebrate orders for using in environmental quality monitoring studies. Instrumental neutron activation analysis - INAA was applied to determine some nutrients and trace elements in invertebrate samples. Sampling by pitfall traps was carried out in riverine ecosystems from the urban area from the Piracicaba Municipality, State of Sao Paulo, Brazil. Invertebrate and reference material samples were irradiated in the nuclear research reactor IEA-R1, Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN. Fragments of a Ni-Cr alloy were irradiated for monitoring the thermal neutron flux. Hymenoptera order was considered the most representative according to the total number of sampled species (about 60%). Significant amounts of Ba, Br, Fe and Sc were found in invertebrates of the order Opiliones. Potassium, rubidium and zinc were highly accumulated in species from Blattodea order, indicating a consistent pattern of accumulation for this invertebrate order. Taking into account the abundance of Hymenoptera order, the chemical composition of its species was significant different at the 95% confidence level for Br and Na in the sampled locals. (author)

  7. Chemical elements in invertebrate orders for environmental quality studies

    International Nuclear Information System (INIS)

    Among the biomonitors of environmental quality, there is a lack of studies on using invertebrates to evaluate quantitatively chemical elements in ecosystems. This group of animals is quite numerous, widely distributed and adaptable to the most diverse environmental conditions. These features are very useful for the environmental quality assessment, as well as the several occurring insect-plant interactions performing essential functions in ecosystems. The objective of this work is to study the variability of chemical composition of invertebrate orders for using in environmental quality monitoring studies. Instrumental neutron activation analysis - INAA was applied to determine some nutrients and trace elements in invertebrate samples. Sampling by pitfall traps was carried out in riverine ecosystems from the urban area from the Piracicaba Municipality, State of Sao Paulo, Brazil. Invertebrate and reference material samples were irradiated in the nuclear research reactor IEA-R1, Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN. Fragments of a Ni-Cr alloy were irradiated for monitoring the thermal neutron flux. Hymenoptera order was considered the most representative according to the total number of sampled species (about 60%). Significant amounts of Ba, Br, Fe and Sc were found in invertebrates of the order Opiliones. Potassium, rubidium and zinc were highly accumulated in species from Blattodea order, indicating a consistent pattern of accumulation for this invertebrate order. Taking into account the abundance of Hymenoptera order, the chemical composition of its species was significant different at the 95% confidence level for Br and Na in the sampled locals. (author)

  8. Magmatic differentiation evidences of the basaltic floods of the Arapey formation:(Uruguay). Brief discussion obtained from the interpretation about some chemical analysis of mayor element

    International Nuclear Information System (INIS)

    Studying the data obtained from some chemical of mayor element, it is possible to define a general trend of magmatic differentiation of the basaltic floods of the Arapey Formation due to crystal-liquid fractionation in the magmatic chamber. The apparent chaos of the chemical composition of the lavas from the point of view of the chronostratigrafic position is explained using a petrogenetic model that tales in account the trends of variation diagrams. It is also demonstrated the inconsistency of the hypothesis of assimilation of eolic sandstone by the lavas as the process responsible for the variation in the chonostratigrafic sequence mentioned above. (author)

  9. The generation of purinome-targeted libraries as a means to diversify ATP-mimetic chemical classes for lead finding.

    Science.gov (United States)

    Felder, Eduard R; Badari, Alessandra; Disingrini, Teresa; Mantegani, Sergio; Orrenius, Christian; Avanzi, Nilla; Isacchi, Antonella; Salom, Barbara

    2012-02-01

    The generation of novel chemotypes in support of our oncology research projects expanded in recent years from a canonical design of kinase-targeted compound libraries to a broader interpretation of purinome-targeted libraries (PTL) addressing the specificity of cancer relevant targets such as kinases and ATPases. Successful screening of structurally diverse ATP-binding targets requires compound libraries covering multiple design elements, which may include phosphate surrogate moieties in ATPase inhibitors or far reaching lipophilic residues stabilizing inactive kinase conformations. Here, we exemplify the design and preparation of drug-like combinatorial libraries and report significantly enhanced screening performance on purinomic targets. We compared overall hit rates of PTL with a simultaneously tested unbiased collection of 200,000 compounds and found consistent superiority of the targeted libraries in all cases. We also analyzed the performance of the largest targeted libraries in comparison with each other and often found striking differences in how a specific target responds to various chemotypes and to whole collections. PMID:22350112

  10. Behavior of radon, chemical compounds and stable elements in underground water; Comportamiento de radon, compuestos quimicos y elementos estables en agua subterranea

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, N.; Segovia, N.; Lopez, M.B.E.; Pena, P. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Armienta, M.A.; Godinez, L. [IGFUNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Seidel, J.L. [ISTEEM, M.S.E. Montpellier (France)

    2001-07-01

    The radon behavior, chemical compounds, major and trace elements in water samples of four springs and three wells of urban and agricultural zones around the Jocotitlan volcano and El Oro region was determined, both of them located in the medium part of the Mexican neo-volcanic axis. The {sup 222} Rn was measured by the liquid scintillation method, the analysis of major components was realized with conventional chemical techniques, while the trace elements were quantified using an Icp-Ms. The average values of the radon concentrations obtained during one year were constant relatively, in an interval from 0.97 to 4.99 Bq/lt indicating a fast transport from the reload area toward the sampling points. the compounds, major and trace elements showed differences which indicate distinct origins of water from the site studies. (Author)

  11. Assessment of atmospheric pollution of chemical elements by epiphytic lichen analysis at the Campus of the Sao Paulo University

    International Nuclear Information System (INIS)

    Air pollution has been a frequent topic of research, due to the effects that it can cause on the health of living organisms, environment and climate. In order to identify pollution sources and their effects, biomonitoring has been studied due to its low cost and possibility of sampling in wide geographic areas. In this study for passive biomonitoring of air pollution levels at the Cidade Universitaria Armando Salles de Oliveira (CUASO), University of Sao Paulo campus, epiphytic lichens of Canoparmelia texana species were used. The lichens collected from tree barks at different sampling sites in the CUASO were cleaned, freeze-dried and ground for analyses. Lichen samples were analyzed by X - ray fluorescence spectrometry (XRFS) and neutron activation analysis (NAA). For XRFS, cylindrical pellets of samples were prepared to determine As, Br, Ca, Cl, Cr, Cu, Fe, K, Mn, Rb, S, Sr and Zn. For NAA, lichen sample aliquots along with synthetic elemental standards were irradiated both for short and long periods at the IEA-R1 nuclear research reactor. The induced activities were measured by a gamma ray spectrometer to determine As, Br, Ca Cd, Cl, Co, Cr, Cs, Cu, Fe, K, La, Mg, Mn, Rb, Sb, Sc, Se, U, V and Zn. The precision and accuracy of the results were evaluated by the analysis of certified reference materials (MRCs). Their results of relative errors and standard deviations were below 15% for most of the elements. The standardized difference or En score values were lower than |1| indicating satisfactory results. Replicate analyses of a lichen sample by XRFS and NAA, indicated good homogeneity of the sample for the elements determined. The lichen results showed that the mean concentrations of As, Br, Ca, Cd, Co, Cr, Cs, Rb, Sb, Se and U were higher in samples from CUASO than those from regions considered unpolluted. For Fe, K, La, S, V and Zn, they were of the same order of magnitude. The correlation study between the elements showed high correlation (r > 0.7) for elements

  12. Use of chemical elements of 1A family by tropical tree species; Uso de elementos quimicos da familia 1A por especies arboreas tropicais

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Andrius M.J.; Paiva, Jose Daniel S. de; Magalhaes, Marcelo R.L. de; Franca, Elvis J. de; Hazin, Clovis A., E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Bacchi, Marcio A.; Fernandes, Elisabete A.N., E-mail: mabacchi@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil).

    2013-07-01

    This study aims to evaluate the distribution of K, Rb and Cs in leaves of trees of the Atlantic Forest through studies of correlation between the chemical elements. For this, we used the Instrumental Neutron Activation Analysis for the quantification of the chemical elements. The concentration ranges found were 6700-24000 mg / kg for K, 16 to 72mg / kg for Rb and 0.08 to 0,92mg / kg for Cs. As Rb has chemical similarity to K, is easily absorbed by plants, leading to a high value (0.9) of the Pearson correlation. For the correlation between K and Cs, no significant values were detected except for some species of the Myrtaceae family. However, average correlations (0.6 of different families. The absence of a specific pattern using of K, Rb and Cs by plants showed great complexity in the distribution of chemical elements in the ecosystem.

  13. Source Apportionment of Elemental Carbon Across the San Francisco Bay Area Using Combined Radiocarbon and Chemical Mass Balances

    Science.gov (United States)

    Yoon, S.; Fairley, D.; Sheesley, R. J.

    2014-12-01

    The San Francisco Bay Area is impacted by ambient particulate matter (PM) from a variety of sources including motor vehicles, biomass burning, off-road vehicles, industry, and meat cooking. Ambient PM, especially fine PM (diameter less than 2.5μm, PM2.5), is known to negatively impact health. Elemental Carbon (EC) is one of the major constituents of PM2.5. It not only negatively affects health but is also a powerful short-lived climate forcer. The State of California and Bay Area Air Quality Management District (BAAQMD) have made efforts in regulating contribution of EC from diesel trucks and wood burning, respectively. These and other efforts have assisted in significantly reducing the annual average PM2.5 concentrations approximately 30% since 2005 and 70% since 1990. Despite these improvements, to better determine the relative contribution of contemporary vs. fossil carbon, radiocarbon source apportionment of EC was conducted on PM2.5 collected in the Bay Area. Measurements of the abundance of 14C in the EC fractions are used to quantify the relative contributions of fossil carbon (fossil fuel combustion, including motor vehicle exhaust) and contemporary carbon (biomass combustion and meat cooking). This comprehensive study included seven sites in the Bay Area and 12 months of sampling starting November 2011 through October 2012. The samples were composited to represent winter (November-February) and non-winter (March-October). In addition to radiocarbon analysis, Chemical Mass Balance (CMB) analysis using bulk PM2.5 composition and selected trace gases was used to understand the split among gasoline, natural gas, and diesel exhaust. Preliminary apportionment of the seven sites shows roughly equal contributions of fossil fuel and biomass burning/cooking for both winter and non-winter samples. There is evidence that the diesel contribution to EC, in particular, has decreased substantially over the last decade.

  14. Characterization of chemical elements in soil submitted to different systems use and management by energy dispersive x-ray fluorescence spectrometry (EDXRF)

    International Nuclear Information System (INIS)

    This study aimed to evaluate the chemical elements levels in soil, submitted to different management systems and use by the Energy Dispersive X-Ray Fluorescence Spectrometry - EDXRF. The systems were T1 - agroforestry (SAF), T2 - native field (CN), T3 - native forest (NM), T4 - tillage forest (PF); T5 - conventional tillage system (SPC) and T6 - system tillage (NT). Samples were collected at 0-10 and 10-20 cm, dried and ground for analysis in EDX-720. The soil showed no difference in the average concentrations of chemical elements analyzed in the profiles, but the systems presented different concentrations of metal elements, and T3 had the highest K, Ca and Zn at 0-10 cm and higher contents of K, Ca, Cu, Zn and Mn in the layer of 10-20 cm. (author)

  15. Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament

    CERN Document Server

    Miettinen, Oskari

    2016-01-01

    The present study aims to characterise the physical and chemical properties of the protostellar core Orion B9-SMM3. The APEX telescope was used to perform a follow-up molecular line survey of SMM3. The following species were identified from the frequency range 218.2-222.2 GHz: $^{13}$CO, C$^{18}$O, SO, para-H$_2$CO, and E$_1$-type CH$_3$OH. The on-the-fly mapping observations at 215.1-219.1 GHz revealed that SMM3 is associated with a dense gas core as traced by DCO$^+$ and p-H$_2$CO. Altogether three different p-H$_2$CO transitions were detected with clearly broadened linewidths (8.2-11 km s$^{-1}$ in FWHM). The derived p-H$_2$CO rotational temperature, $64\\pm15$ K, indicates the presence of warm gas. We also detected a narrow p-H$_2$CO line (FWHM=0.42 km s$^{-1}$) at the systemic velocity. The p-H$_2$CO abundance for the broad component appears to be enhanced by two orders of magnitude with respect to the narrow line value ($\\sim3\\times10^{-9}$ versus $\\sim2\\times10^{-11}$). The detected methanol line shows ...

  16. Seasonal and spatial variation of trace elements in multi-size airborne particulate matters of Beijing, China: Mass concentration, enrichment characteristics, source apportionment, chemical speciation and bioavailability

    Science.gov (United States)

    Gao, Jiajia; Tian, Hezhong; Cheng, Ke; Lu, Long; Wang, Yuxuan; Wu, Ye; Zhu, Chuanyong; Liu, Kaiyun; Zhou, Junrui; Liu, Xingang; Chen, Jing; Hao, Jiming

    2014-12-01

    The seasonal and spatial variation characteristics of 19 elements (Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Sb, Se, Zn) in TSP/PM10/PM2.5 samples were investigated, which were collected from April 2011 to January 2012 simultaneously at an urban downtown site, a traffic roadside site, a suburban site, and a rural site in Beijing. The elevated concentrations of several toxic trace elements (As, Cd, Mn, Ni, Pb, etc.) in particles revealed that the contamination of toxic elements in Beijing could not be neglected. Positive matrix factorization method (PMF) was applied for source apportionment of trace elements in PM, and three factors (crust related sources, combustion sources, and traffic and steel industrial related sources) were identified. Furthermore, the chemical speciation and bioavailability of various elements were identified by applying European Community Bureau of Reference (BCR) procedure. Our results showed that eight toxic elements (As, Cd, Cr, Cu, Ni, Pb, Sb and Zn) exhibited higher mobility in PM2.5 than in PM10. Notably, elements of As, Cd, Pb and Zn were presented with higher mobility than the other elements, and these elements were lightly to release into the environment and easily available to human body. Additionally, As, Cd, Pb and Zn also accounted for higher percentages in the bound to mobile fractions at the central urban areas of Beijing. Therefore, special concerns should be paid to these toxic trace elements which had relatively high mobility in fine particles, when planning and implementing the comprehensive air pollution mitigation policies in Beijing.

  17. Distant elements of surprise

    International Nuclear Information System (INIS)

    The fortuitous alignment of a quasar and a distant galaxy has enabled astronomers to unravel the origin and evolution of chemical elements. Cosmologists and fossil hunters have more in common than it might first appear. Palaeontologists analyse fossil records of the last 3.5 billion years to track the evolution of life on Earth. Motivated by a similar curiosity, astronomers are searching for chemical elements in stars and cosmic gas to understand the origin of the chemistry of the universe, and how it has developed since the Big Bang. The basic theoretical framework of the universe's chemistry has been in place for half a century. The lightest elements - hydrogen and helium, along with trace amounts of deuterium and lithium - were created within a few minutes of the Big Bang. All of the other elements were assembled at much later times by the fusion of hydrogen and helium nuclei in the interior of stars. Some of these elements were dispersed through space in the violent supernova explosions with which some stars end their lives. They were then condensed into subsequent generations of stars, and into the planets that formed around them. Some of these elements were eventually incorporated into organic structures and became essential for life on Earth. This cosmic cycle continues to the present day. The closest region of active star formation is the Orion nebula, which is visible to anyone who looks up at the sky on a clear winter's night. But the details of the cycle are still far from clear. For example, we do not know when most of the elements were produced in the universe as a whole, or which stars were responsible for producing which elements. In order to unravel the path of chemical evolution we have to shift our attention to much further away than the Orion nebula. (U.K.)

  18. A window on the efficiency of the s-process in AGB stars: chemical abundances of n-capture elements in the planetary nebula NGC 3918

    CERN Document Server

    Madonna, S; Luridiana, V; Sterling, N C; Morisset, C

    2015-01-01

    The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R~40000) UVES at VLT spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in the progenitor star of NGC 3918.

  19. Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant

    CERN Document Server

    Ledenyov, Oleg P

    2013-01-01

    The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antin...

  20. Semantic Analysis of Virtual Classes and Nested Classes

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1999-01-01

    Virtual classes and nested classes are distinguishing features of BETA. Nested classes originated from Simula, but until recently they have not been part of main stream object- oriented languages. C++ has a restricted form of nested classes and they were included in Java 1.1. Virtual classes is the...... classes and parameterized classes have been made. Although virtual classes and nested classes have been used in BETA for more than a decade, their implementation has not been published. The purpose of this paper is to contribute to the understanding of virtual classes and nested classes by presenting the...

  1. Chemistry of the transactinide elements

    International Nuclear Information System (INIS)

    The synthesis and decay of the elements 104, 105 and 106 are described as well as the chemistry of the elements in the gaseous and liquid phase. The electron configurations of the ground state of the elements 105 and higher are described, as well as further chemical properties. (SR)

  2. TABLE OF RADIOACTIVE ELEMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    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. TABLE OF RADIOACTIVE ELEMENTS

    International Nuclear Information System (INIS)

    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

  4. Identifying the best iron-peak and $\\alpha$-capture elements for chemical tagging: The impact of the number of lines on measured scatter

    CERN Document Server

    Adibekyan, V; Santos, N C; Sousa, S G; Faria, J P; Delgado-Mena, E; Oshagh, M; Tsantaki, M; Hakobyan, A A; Hernandez, J I Gonzalez; Suarez-Andres, L; Israelian, G

    2015-01-01

    The main goal of this work is to explore which elements carry the most information about the birth origin of stars and as such that are best suited for chemical tagging. We explored different techniques to minimize the effect of outlier value lines in the abundances by using Ni abundances derived for 1111 FGK type stars.We evaluated how the limited number of spectral lines can affect the final chemical abundance. Then we were able to make an efficient even footing comparison of the [X/Fe] scatter between the elements that have different number of observable spectral lines in the studied spectra. We found that the most efficient way of calculating the average abundance of elements when several spectral lines are available is to use a weighted mean (WM) where as a weight we considered the distance from the median abundance. This method can be effectively used without removing suspected outlier lines.We showed that when the same number of lines is used to determine chemical abundances, the [X/Fe] star-to-star sc...

  5. Effect of rare earth elements from monazite on growth-vigor and chemical composition of Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Sharoubeem, H.H.; Milad, N.E.

    1966-01-01

    This investigation deals with the effect of different concentrations of rare earth elements (as monazite extract containing Th, Ce, La, Pr, and Nd in the form of nitrates) on the growth and nutritional status of Phaseolus vulgaris. Phaseolus vulgaris plants were grown in sand cultures to which rare earths were added to supply 2.5, 5, 7.5, and 10 ppm. Growth of both tops and roots showed a marked response to rare earths application, especially in the development of tops. The addition of rare earths to the culture solution resulted in better development of plant tops and roots up to 5 ppm; above 5 ppm there was less growth but always more than tops and roots of plants grown in culture medium without rare earths. The application of rare earth elements increased the water content of roots, but not of tops, to a maximum at the level of 5 ppm. In response to rare earth elements the dry matter of tops increases more in proportion than does the dry matter of their roots; top/root ratios are, consequently, higher in the presence or rare earths. The application of rare earths increased the nitrogen, potassium, and sodium contents of the experimental plant tops up to a maximum at the level of 5 ppm rare earths. With further increase of rare earths these contents were decreased. The reverse was true with regard to calcium, magnesium, and phosphorus contents.

  6. Geophagy Practices and the Content of Chemical Elements in the Soil Eaten by Pregnant Women in Artisanal and Small Scale Gold Mining Communities in Tanzania.

    OpenAIRE

    Nyanza, Elias C; Joseph, Mary; Premji, Shahirose S.; Thomas, Deborah SK; Mannion, Cynthia

    2014-01-01

    Background Geophagy, a form of pica, is the deliberate consumption of soil and is relatively common across Sub-Saharan Africa. In Tanzania, pregnant women commonly eat soil sticks sold in the market (pemba), soil from walls of houses, termite mounds, and ground soil (kichuguu). The present study examined geophagy practices of pregnant women in a gold mining area of Geita District in northwestern Tanzania, and also examined the potential for exposure to chemical elements by testing soil sample...

  7. Teaching and Learning in Chemical Product Engineering - an Evolving par of the Chemical Engineering Curriculum

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Kiil, Søren; Wesselingh, Johannes

    2007-01-01

    helping the individual to become more assertive and understanding of personal assets. These teaching elements included in Chemical Product Engineering represent a series of general issues in Chemical Engineering Education, which must be discussed as the education is going to adapt to the changes of the......Over the last decade Chemical Product Engineering has evolved as part of the Chemical Engineering Curriculum at several universities in Europe and America. At the DTU Chemical Product Engineering was introduced in 2000. This presentation will report on the experiences gained from teaching classes...... and preparing a text book on the subject. [1] Chemical Product Engineering is solidly based on chemical technical and engineering knowledge. Furthermore, the subject naturally calls for a holistic approach to teaching and learning and introduces elements which target transferable and professional...

  8. Alguns aspectos históricos da classificação periódica dos elementos químicos Some historical aspects of the periodic classification of the chemical elements

    Directory of Open Access Journals (Sweden)

    Mario Tolentino

    1997-02-01

    Full Text Available A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.

  9. Alguns aspectos históricos da classificação periódica dos elementos químicos Some historical aspects of the periodic classification of the chemical elements

    OpenAIRE

    Mario Tolentino; Rocha-Filho, Romeu C.; Aécio Pereira Chagas

    1997-01-01

    A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.

  10. Studies on the Elemental and Chemical Constituent of Some Myanmar Indigenous Medicinal Plants used for the Treatment of Hypertension

    International Nuclear Information System (INIS)

    Study of Myanmar indigenous medicinal plants used for the treatment of hypertension was conducted. The samples studied were Gant-ka-lar (Gisekia pharnaceoides), Dan-da-lun (Moringa oleifera), Egayit (Millingtonia hortensis), Sue-pan (Carthumas tinctarius), Kauk-yoe-new (Oxystelma esculentum), Shauk (Citrus medica), Kyet-lei-san (Vitex glabrata), Sin-ngo-myet (Eleusine indica). In all these samples, qualitative determination of potassium had been determined by High Purity Germanium gamma counter and quantitative determination had been accomplished by NaI (Tl) gamma scintillation counting and ''Aloka'' gross gamma counting methods. In addition, quantitative determination of the elements in these samples was carried out by Atomic Absorption Spectrophotometry and Flame photometry. Relative quantitative elemental analysis of these samples was carried out by using Energy Dispersive X-ray Fluorescence (EDXRF) spectrometry

  11. The Effect of Risk Factors on the Levels of Chemical Elements in the Tibial Plateau of Patients with Osteoarthritis following Knee Surgery

    Directory of Open Access Journals (Sweden)

    Natalia Lanocha-Arendarczyk

    2015-01-01

    Full Text Available The aim of this study was to evaluate the aforementioned chemical elements in tibial plateau samples obtained during knee arthroplasty. The gender-specific analysis of chemical element levels in the bone samples revealed that there were statistically significant differences in the concentration of Pb and Se/Pb ratio. The contents of elements in the tibial plateau in the patients with osteoarthritis (OA can be arranged in the following descending order: F− > K > Zn > Fe > Sr > Pb > Mn > Se > Cd > THg. We observed statistical significant effects of environmental factors including smoking, seafood diet, and geographical distribution on the levels of the elements in tibial bone. Significant positive correlation coefficients were found for the relationships K-Cd, Zn-Sr, Zn-F−, THg-Pb, Pb-Cd, Se-Se/Pb, Se-Se/Cd, Se/Pb-Se/Cd, Pb-Cd/Ca, Cd-Cd/Ca, and F−-F−/Ca·1000. Significant negative correlations were found for the relationships THg-Se/Pb, Pb-Se/Pb, Cd-Se/Pb, K-Se/Cd, Pb-Se/Cd, Cd-Se/Cd, THg-Se/THg, Pb-Se/THg, Se-Pb/Cd, Zn-Cd/Ca, and Se/Cd-Cd/Ca. The results reported here may provide a basis for establishing reference values for the tibial plateau in patients with OA who had undergone knee replacement surgery. The concentrations of elements in the bone with OA were determined by age, presence of implants, smoking, fish and seafood diet, and sport activity.

  12. Chemical characterization of high-temperature arc gasification slag with a focus on element release in the environment.

    Science.gov (United States)

    Roessler, Justin G; Oehmig, Wesley N; Blaisi, Nawaf I; Townsend, Timothy G

    2014-07-15

    High-temperature arc gasification (HTAG) has been proposed as a viable technology for the generation of energy and the production of saleable byproducts from municipal solid waste (MSW). Total concentrations of elements in HTAG slag were assessed and indicated a high partitioning of trace elements (Pb, Cd, and As) into the flue gas, an issue of concern when assessing the air pollution control residues (APCR) status as a hazardous waste. Hazardous waste leaching tests [such as the toxicity characteristic leaching procedure (TCLP)] were performed and confirmed that the slag did not meet U.S. criteria for a hazardous waste. Leaching was assessed using batch and column tests; the results revealed that Sb and Al were elevated in respect to risk-based regulatory thresholds. Slag samples were carbonated to simulate weathering effects, and although leachable concentrations of Al did decrease by an order of magnitude, Sb concentrations were found to increase. Low total concentrations of certain trace elements (As, Cd, and Pb), with respect to MSW incineration bottom ashes support the potential for reuse of HTAG slag; however, leaching of elements (Pb, Al, and Sb) in batch and column tests indicate that proper engineering controls would need to be taken to ensure protection of water supplies in a reuse application. PMID:24912855

  13. The T box regulatory element controlling expression of the class I lysyl-tRNA synthetase of Bacillus cereus strain 14579 is functional and can be partially induced by reduced charging of asparaginyl-tRNAAsn

    LENUS (Irish Health Repository)

    Foy, Niall

    2010-07-22

    Abstract Background Lysyl-tRNA synthetase (LysRS) is unique within the aminoacyl-tRNA synthetase family in that both class I (LysRS1) and class II (LysRS2) enzymes exist. LysRS1 enzymes are found in Archaebacteria and some eubacteria while all other organisms have LysRS2 enzymes. All sequenced strains of Bacillus cereus (except AH820) and Bacillus thuringiensis however encode both a class I and a class II LysRS. The lysK gene (encoding LysRS1) of B. cereus strain 14579 has an associated T box element, the first reported instance of potential T box control of LysRS expression. Results A global study of 891 completely sequenced bacterial genomes identified T box elements associated with control of LysRS expression in only four bacterial species: B. cereus, B. thuringiensis, Symbiobacterium thermophilum and Clostridium beijerinckii. Here we investigate the T box element found in the regulatory region of the lysK gene in B. cereus strain 14579. We show that this T box element is functional, responding in a canonical manner to an increased level of uncharged tRNALys but, unusually, also responding to an increased level of uncharged tRNAAsn. We also show that B. subtilis strains with T box regulated expression of the endogenous lysS or the heterologous lysK genes are viable. Conclusions The T box element controlling lysK (encoding LysRS1) expression in B. cereus strain 14579 is functional, but unusually responds to depletion of charged tRNALys and tRNAAsn. This may have the advantage of making LysRS1 expression responsive to a wider range of nutritional stresses. The viability of B. subtilis strains with a single LysRS1 or LysRS2, whose expression is controlled by this T box element, makes the rarity of the occurrence of such control of LysRS expression puzzling.

  14. The T box regulatory element controlling expression of the class I lysyl-tRNA synthetase of Bacillus cereus strain 14579 is functional and can be partially induced by reduced charging of asparaginyl-tRNAAsn

    Directory of Open Access Journals (Sweden)

    Conant Gavin C

    2010-07-01

    Full Text Available Abstract Background Lysyl-tRNA synthetase (LysRS is unique within the aminoacyl-tRNA synthetase family in that both class I (LysRS1 and class II (LysRS2 enzymes exist. LysRS1 enzymes are found in Archaebacteria and some eubacteria while all other organisms have LysRS2 enzymes. All sequenced strains of Bacillus cereus (except AH820 and Bacillus thuringiensis however encode both a class I and a class II LysRS. The lysK gene (encoding LysRS1 of B. cereus strain 14579 has an associated T box element, the first reported instance of potential T box control of LysRS expression. Results A global study of 891 completely sequenced bacterial genomes identified T box elements associated with control of LysRS expression in only four bacterial species: B. cereus, B. thuringiensis, Symbiobacterium thermophilum and Clostridium beijerinckii. Here we investigate the T box element found in the regulatory region of the lysK gene in B. cereus strain 14579. We show that this T box element is functional, responding in a canonical manner to an increased level of uncharged tRNALys but, unusually, also responding to an increased level of uncharged tRNAAsn. We also show that B. subtilis strains with T box regulated expression of the endogenous lysS or the heterologous lysK genes are viable. Conclusions The T box element controlling lysK (encoding LysRS1 expression in B. cereus strain 14579 is functional, but unusually responds to depletion of charged tRNALys and tRNAAsn. This may have the advantage of making LysRS1 expression responsive to a wider range of nutritional stresses. The viability of B. subtilis strains with a single LysRS1 or LysRS2, whose expression is controlled by this T box element, makes the rarity of the occurrence of such control of LysRS expression puzzling.

  15. Determination of elemental and physico-chemical quality of well waters and assessment of their impacts on public health

    International Nuclear Information System (INIS)

    Water is one the most important constituents of the human environment. The relevance of determining pollutants in drinking water is obvious because it is among the pathways of contaminants to enter the organism. The aim of this work is to determine water quality and thus to assess the effects on humans. Total Reflection X-Ray Fluorescence analysis method (TXRF) has been applied for the measurements of trace elements in drinking water. The analyses were performed without any pre-concentration of samples. Colorimetric method was used for the analysis of major components of water. The samples were collected in the regions towards southern Antananarivo. Well waters were sampled because they are the type of drinking water consumed by the population in these regions. Analytical results showed that the determined concentrations of toxic elements such as chromium and lead are largely lower than the maximum allowed values, except two sites were lead concentration exceeds it. For Fe, five sites showed water samples having iron concentrations higher than Recommended Value (50 μg.L-1) fixed by the European Union. The mean values for barium and manganese were above the maximum allowed value established by law in some sites. This is mainly due to the geology of the terrain. Concerning nitrate, three sites showed higher concentration than the maximum allowed value.

  16. Analysis of physico-chemical processes in a multicell TFE with communicating cavities of fuel element and interelectrode gap

    International Nuclear Information System (INIS)

    One studied the behaviour of the basic ingredients of uranium dioxide, of gas-forming impurities, of fission products and the transfer of the emitter material to the collector in terms of the communicating spaces of a fuel element and the multiple-unit PGC electrode/electrode gap. Paper presents the results of the out-of-pile studies of the condensation temperature ranges of fission products with the use of the uranium dioxide base reference fuel and the PGC loop tests. Precipitation of fission products on the collector is shown to be negligible one, transfer of tungsten from the emitter to the collector may level the mentioned effect

  17. FINITE ELEMENT METHOD AND ANALYSIS FOR CHEMICAL-FLOODING SIMULATION

    Institute of Scientific and Technical Information of China (English)

    YUAN Yirang

    2000-01-01

    This article discusses the enhanced oil recovery numerical simulation of the chemical-flooding (such as surfactants, alcohol, polymers) composed of three-dimensional multicomponent, multiphase and incompressible mixed fluids. The mathematical model can be described as a coupled system of nonlinear partial differential equations with initialboundary value problems. From the actual conditions such as the effect of cross interference and the three-dimensional characteristic of large-scale science-engineering computation, this article puts forward a kind of characteristic finite element fractional step schemes and obtain the optimal order error estimates in L2 norm. Thus we have thoroughly solved the well-known theoretical problem proposed by a famous scientist, R. E. Ewing.

  18. The effect of rotation on the abundances of the chemical elements of the A-type stars in the Praesepe cluster

    CERN Document Server

    Fossati, L; Landstreet, J; Wade, G; Kochukhov, O; Monier, R; Weiss, W; Gebran, M

    2008-01-01

    We study how chemical abundances of late B-, A- and early F-type stars evolve with time, and we search for correlations between the abundance of chemical elements and other stellar parameters, such as effective temperature and Vsini. We have observed a large number of B-, A- and F-type stars belonging to open clusters of different ages. In this paper we concentrate on the Praesepe cluster (log t = 8.85), for which we have obtained high resolution, high signal-to-noise ratio spectra of sixteen normal A- and F-type stars and one Am star, using the SOPHIE spectrograph of the Observatoire de Haute-Provence. For all the observed stars, we have derived fundamental parameters and chemical abundances. In addition, we discuss another eight Am stars belonging to the same cluster, for which the abundance analysis had been presented in a previous paper. We find a strong correlation between peculiarity of Am stars and Vsini. The abundance of the elements underabundant in Am stars increases with Vsini, while it decreases f...

  19. Extractability of risk elements and nutrition elements from ash

    OpenAIRE

    Hrma, Jiří

    2012-01-01

    The thesis „Extractability of risk elements and nutrition elements from ash“ studies the determination of physicochemical properties of ash and compares the mobility of heavy metals and nutrition elements in various samples. The aim of the study was to determine the extractability of heavy metals and nutrition elements from biomass ash and their chemical speciation using sequential extraction procedure based upon Tessier which was modified for given matrix. The results permit to classify m...

  20. ZAP-70 and p72syk are signaling response elements through MHC class II molecules

    DEFF Research Database (Denmark)

    Kanner, S B; Grosmaire, L S; Blake, J;

    1995-01-01

    -activated human T-cells. In both tonsillar B-lymphocytes and B-cell leukemia lines, p72syk was rapidly phosphorylated on tyrosine residues following HLA-DR cross-linking. Tyrosine phosphorylation of p72syk induced through ligation of either the B-cell antigen receptor or class II molecules was potently inhibited...... intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA-DR in...... antibody induced receptor ligation, bacterial superantigen (SEA and SEB) treatment of HLA-DR+ T-cells stimulated ZAP-70 tyrosine phosphorylation, consistent with class II transmembrane signaling by ligation of HLA-DR and V beta in cis. Modulation of the TCR/CD3 led to abrogation of class II induced ZAP-70...

  1. Chemical properties of transactinides

    Science.gov (United States)

    Gäggeler, H. W.

    2005-09-01

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified.

  2. Chemical properties of transactinides

    International Nuclear Information System (INIS)

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified. (orig.)

  3. Chemical properties of transactinides

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, H.W. [Paul Scherrer Institut, Villigen (Switzerland); University of Bern, Bern (Switzerland)

    2005-09-01

    First investigations of chemical properties of bohrium (Z = 107) and hassium (Z = 108) showed an expected behaviour as ordinary members of groups 7 and 8 of the periodic table. Two attempts to study element 112 yielded some indication for a behaviour like a very volatile noble metal. However, a very recent experiment to confirm this preliminary observation failed. Two examples are described how chemical studies may help to support element discovery claims from purely physics experiments. The two examples are the discovery claims of the elements 112 and 115, respectively, where the progenies hassium and dubnium were chemically identified. (orig.)

  4. Sterilization of health care products - Chemical indicators - Part 3: Class 2 indicator systems for use in the Bowie and Dick-type steam penetration test. 2. ed.

    International Nuclear Information System (INIS)

    This part of ISO 11140 specifies the requirements for chemical indicators to be used in the steam penetration test for steam sterilizers for wrapped goods, e.g. instruments and porous materials. The indicator for this purpose is a Class 2 indicator as described in ISO 11140-1. Indicators complying with this part of ISO 11140 are intended for use in combination with the standard test pack as described in EN 285. This part of ISO 11140 does not consider the performance of the standard test pack, but does specify the performance of the indicator systems.The paper provides information on scope, normative references, terms and definitions, general requirements, indicator system format, performance requirements, packaging and labelling and quality assurance. 11 annexes report on the determination of strength after steam sterilization, the estimation of visual difference between colour of the substrate and the changed (or unchanged) indicator system by determination of relative reflectance density, the determination of indicator colour change on exposure to dry saturated steam, the determination of indicator colour change on exposure to dry heat, the accelerated ageing of test samples, the determination of transfer of indicator to standard test pack on processing, the determination of shelf life of the product, the steam exposure apparatus, the determination of sensitivity of the indicator to the presence of air, the air injection system and the standard test pack. Finally a bibliography is provided.

  5. Multi trace element analysis of dry biological materials by neutron activation analysis including a chemical group separation

    International Nuclear Information System (INIS)

    Multi-element analysis of dry biological material by neutron activation analysis has to include radiochemical separation. The evaporation process is described in terms of the half-volume. The pretreatment of the samples and the development of the destruction-evaporation apparatus are described. The successive adsorption steps with active charcoal, Al2O3 and coprecipitation with Fe(OH)3 are described. Results obtained for standard reference materials are summarized. (G.T.H.)

  6. Differences in determination of chemical elements in soil and attic dust samples due to various acid treatments, Slovenia

    Directory of Open Access Journals (Sweden)

    Robert Šajn

    2003-12-01

    Full Text Available The paper gives an assessment of relationship existing between analytical values of samples, which were treated with two different acid procedures: four acid digestion and extraction in aqua regia. The sample population consisted of 256 soil samples and 139 atticdust samples collected within the frame of various geochemical studies in Slovenia. After acid treatments, elementary composition of the samples was determined by means of ICP method. As we were interested in functional relationships between both treatment procedures, we performed bivariate analysis of elementary compositions. A regression line based on the logarithms of data was used as a basic correlation indicator. We correlated the following 31 elements: Al, Ag, As, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mg, Mn,Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, Th, Ti, U, V, W and Zn.The majority of analytical values for elements in our samples, treated with both procedures,showed a high degree of correlation and a good functional relationship. A weak relationship existed only between those elements that were on detection limits of theanalytical method or had a weak variability (Ag, Ba, Bi, K, Na, Ti, and W. On the basis of the results of double treatment and analysis of samples we calculated the boundary, warning and critical values, which are related to four acid digestion.

  7. Residues of Chern classes

    OpenAIRE

    Suwa, Tatsuo; 諏訪, 立雄

    2003-01-01

    If we have a finite number of sections of a complex vector bundle E over a manifold M, certain Chern classes of E are localized at the singular set S, i.e., the set of points where the sections fail to be linearly independent. When S is compact, the localizations define the residues at each connected component of S by the Alexander duality. If M itself is compact, the sum of the residues is equal to the Poincaré dual of the corresponding Chern class. This type of theory is also developed for ...

  8. Residues of Chern classes

    OpenAIRE

    Suwa, Tatsuo

    2003-01-01

    If we have a finite number of sections of a complex vector bundle $E$ over a manifold $M$ , certain Chern classes of $E$ are localized at the singular set $S$ , i.e., the set of points where the sections fail to be linearly independent. When $S$ is compact, the localizations define the residues at each connected component of $S$ by the Alexander duality. If $M$ itself is compact, the sum of the residues is equal to the Poincaré dual of the corresponding Chern class. This type of theory is als...

  9. Progress in microbial activity and chemical properties of a trace element polluted soil under assisted natural remediation

    OpenAIRE

    Pérez de Mora, Alfredo; Burgos, Pilar; Cabrera, Francisco, (S.I.) (1724-1799); Madejón, Engracia

    2012-01-01

    In this work, we studied the temporal dynamics of several microbiological properties in a trace element polluted soil under the influence of various amendments and/or a plant cover during a 30 month-period. The experiment was carried out in containers filled with ca. 150 kg of contaminated soil. Seven treatments were established: four organic (leonardite LEO, litter LIT, municipal waste compost MWC and biosolid compost BC) and one inorganic (sugarbeet lime SL), where the gra...

  10. Social Class Dialogues and the Fostering of Class Consciousness

    Science.gov (United States)

    Madden, Meredith

    2015-01-01

    How do critical pedagogies promote undergraduate students' awareness of social class, social class identity, and social class inequalities in education? How do undergraduate students experience class consciousness-raising in the intergroup dialogue classroom? This qualitative study explores undergraduate students' class consciousness-raising in an…

  11. Some Chemical Elements in Gamma Irradiated Adults of the Mediterranean Fruit Fly, Ceratitis capitata (Wied.) Fed on Different Diets

    International Nuclear Information System (INIS)

    The elemental composition of four yeast diets differ in protein composition and mixed with sugar as a carbohydrate source were compared with a standard yeast diet used for the mass rearing of med fly C. capitata. The cost availability and the effects on the quality of reared flies were the main measures for these comparisons. Moreover, the elemental composition of reared flies on the tested diets either irradiated to gamma radiation or normal beside full grown pupae (F1) were detected and compared with those reared on standard diet . Data obtained revealed that ten elements (K, N, Na, P, Ca, Fe, Mg, Zn, Mn and Cu) were detected and classified according to their quantities .However those quantities varied according to the type of used yeast ,insect stage , insect sex and irradiated dose. The major group (K, N, Na and P), moderate group (Ca, Fe and Mg) and minor group (Zn, Mn and Cu) remained unchanged although their quantities were changed inside each group. In addition, a significant increase in K, N, Na, P and Ca when diet No.4 (D4) was used to feed flies. These findings may enhance the opportunity of sterile insect technique (SIT). However Fe and Zn ions were decreased with changing the standard yeast and this is may contradict SIT. Also when normal females fed on all tested yeasts, the concentrations of the ten elements increased as compared to those fed on standard diet. These results may increase the efficiency of sterilized reared insects to compete with the native insects in the field

  12. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    International Nuclear Information System (INIS)

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  13. The study of chemical composition and elemental mappings of colored over-glaze porcelain fired in Qing Dynasty by micro-X-ray fluorescence

    International Nuclear Information System (INIS)

    It is very difficult to measure the chemical composition of colored pigments of over-glaze porcelain by X-ray fluorescence because it contains high concentration of Pb. One of the disadvantages of our polycapillary optics is that it has low transmission efficiency to the high energy X-ray. However, it is beneficial to measure the chemical compositions of rich Pb sample. In this paper, we reported the performances of a tabletop setup of micro-X-ray fluorescence system base on slightly focusing polycapillary and its applications for analysis of rich Pb sample. A piece of Chinese ancient over-glaze porcelain was analyzed by micro-X-ray fluorescence. The experimental results showed that the Cu, Fe and Mn are the major color elements. The possibilities of the process of decorative technology were discussed in this paper, also.

  14. The study of chemical composition and elemental mappings of colored over-glaze porcelain fired in Qing Dynasty by micro-X-ray fluorescence

    Science.gov (United States)

    Lin, Cheng; Meitian, Li; Youshi, Kim; Changsheng, Fan; Shanghai, Wang; Qiuli, Pan; Zhiguo, Liu; Rongwu, Li

    2011-02-01

    It is very difficult to measure the chemical composition of colored pigments of over-glaze porcelain by X-ray fluorescence because it contains high concentration of Pb. One of the disadvantages of our polycapillary optics is that it has low transmission efficiency to the high energy X-ray. However, it is beneficial to measure the chemical compositions of rich Pb sample. In this paper, we reported the performances of a tabletop setup of micro-X-ray fluorescence system base on slightly focusing polycapillary and its applications for analysis of rich Pb sample. A piece of Chinese ancient over-glaze porcelain was analyzed by micro-X-ray fluorescence. The experimental results showed that the Cu, Fe and Mn are the major color elements. The possibilities of the process of decorative technology were discussed in this paper, also.

  15. Periodic table of elements

    International Nuclear Information System (INIS)

    Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF)

  16. Chemical bioimaging for the subcellular localization of trace elements by high contrast TEM, TEM/X-EDS, and NanoSIMS.

    Science.gov (United States)

    Penen, Florent; Malherbe, Julien; Isaure, Marie-Pierre; Dobritzsch, Dirk; Bertalan, Ivo; Gontier, Etienne; Le Coustumer, Philippe; Schaumlöffel, Dirk

    2016-09-01

    Chemical bioimaging offers an important contribution to the investigation of biochemical functions, biosorption and bioaccumulation processes of trace elements via their localization at the cellular and even at the subcellular level. This paper describes the combined use of high contrast transmission electron microscopy (HC-TEM), energy dispersive X-ray spectroscopy (X-EDS), and nano secondary ion mass spectrometry (NanoSIMS) applied to a model organism, the unicellular green algae Chlamydomonas reinhardtii. HC-TEM providing a lateral resolution of 1nm was used for imaging the ultrastructure of algae cells which have diameters of 5-10μm. TEM coupled to X-EDS (TEM/X-EDS) combined textural (morphology and size) analysis with detection of Ca, P, K, Mg, Fe, and Zn in selected subcellular granules using an X-EDS probe size of approx. 1μm. However, instrumental sensitivity was at the limit for trace element detection. NanoSIMS allowed chemical imaging of macro and trace elements with subcellular resolution (element mapping). Ca, Mg, and P as well as the trace elements Fe, Cu, and Zn present at basal levels were detected in pyrenoids, contractile vacuoles, and granules. Some metals were even localized in small vesicles of about 200nm size. Sensitive subcellular localization of trace metals was possible by the application of a recently developed RF plasma oxygen primary ion source on NanoSIMS which has shown good improvements in terms of lateral resolution (below 50nm), sensitivity, and stability. Furthermore correlative single cell imaging was developed combining the advantages of TEM and NanoSIMS. An advanced sample preparation protocol provided adjacent ultramicrotome sections for parallel TEM and NanoSIMS analyses of the same cell. Thus, the C. reinhardtii cellular ultrastructure could be directly related to the spatial distribution of metals in different cell organelles such as vacuoles and chloroplast. PMID:27288221

  17. A New Class of 99mTc(I) Agents for SLND: Chemical Design and Synthesis. Chapter 5

    International Nuclear Information System (INIS)

    The unique features of the organometallic technetium and rhenium tricarbonyl moiety have earned considerable attention in the design of novel specific radiopharmaceuticals in recent years. As part of the CRP focused on the Development of 99mTc Radiopharmaceuticals for Sentinel Node Detection and Cancer Diagnosis, the design of mannosylated dextran derivatives loaded with pyrazolyl (pz) diamine and cysteine chelating units for coordination to the organometallic core fac-[M(CO)3]+ (M = Re, 99mTc) are reported in this chapter. The corresponding rhenium derivatives were prepared as congeners of the 99mTc(CO)3 mannosylated dextran and used as non-radioactive alternatives for large scale synthesis and structural characterization. (author)

  18. Some Thinking on the Teaching of Adult Chemical Class%对成人化学课堂教学的几点思考

    Institute of Scientific and Technical Information of China (English)

    刘志娟

    2012-01-01

    Chemistry is a practical, creative discipline which is closely related with our daily lite. 'lhe teaching materials of traditional chemistry curriculum are lack of contact with social life, which make a variety of chemical learning boring. In view of the practical conditions of the students, the paper introduces the history of chemistry, chemistry in the daily life, social issues and chemistry front into chemistry teaching in class, so that the students can feel the presence of chemistry and improve the learning efficiency.%化学作为一门实用性、创造性都比较突出的学科,与我们的衣食住行密切相关。传统的化学课程,教材内容缺少与社会生活的联系,使本来丰富多彩的化学学习变得枯燥无味。结合学生的实际情况,通过在课堂教学中,将化学史、日常生活中的化学、社会热点问题、化学前沿引入化学教学,让学生切身感受到化学的存在,提高了学习效率,取得了不错的教学效果。

  19. The use of neutron activation analysis for particle size fractionation and chemical characterization of trace elements in urban air particulate matter

    International Nuclear Information System (INIS)

    The concentration of more than 25 trace elements have been determined in total air particulate matter and in the size segregated fractions from the urban area of Pavia (North Italy). The PM10 fraction was also collected and analyzed. A study of the solubility in water and in physiological solution of the trace elements contained in the PM10 was also carried out. The resulting solutions were further submitted to column chromatography using Chelex 100 to perform a preliminary chemical characterization. INAA was used as the main analytical technique. ET-AAS was used for all Pb and Cd measurements and, in some cases, for the analysis of V, Mn, Cu and Ni. (author)

  20. The distribution of mercury and other trace elements in the bones of two human individuals from medieval Denmark – the chemical life history hypothesis

    DEFF Research Database (Denmark)

    Rasmussen, Kaare Lund; Skytte, Lilian; Pilekær, Christian;

    2013-01-01

    Excavating human skeletons is the closest archaeologists can get to the people who lived in the past. Once excavated the bones are often analysed chemically in order to yield as much information as possible. Most archaeometric analyses performed on samples of human skeletal remains have been...... individuals can be clearly distinguished by Principal Component Analysis of all the measured trace elements.Our data support a previously published hypothesis that the elemental ratios Sr/Ca, Ba/Ca and Mg/Ca are indicative of provenance. Aluminium, Fe and Mn can be attributed to various forms of diagenesis......, while Hg is not present in sufficiently large amounts in the surrounding soil to allow diagenesis to explain the high Hg values in the trabecular tissue. Instead we propose that Hg must originate from decomposed soft tissue....

  1. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  2. Chemical Identification of Archaeological Obsidian from Lagartero, Chiapas, Mexico, Using Main and Trace Elements Determined by PIXE. Chapter 10

    International Nuclear Information System (INIS)

    Proton induced X ray emission (proton PIXE) analysis has been used for determination of minor and trace element concentrations of archaeological obsidian samples, which were collected at the site at Lagartero, Chiapas, Mexico. Samples of Mexican and Guatemalan sources were also analysed. Statistical treatments such as principal component analyses were applied to the data set. Obsidians from Lagartero were identified as coming from the Guatemalan sources of Ixtepeque and El Chayal, with one sample from Ucareo/Zinapecuaro, Mexico. These results indicate that there was contact between the population of Lagartero and other Mayans or Mesoamericans. (author)

  3. SHIP, the Separator for Heavy Ion Reaction Products, and the making of the heaviest atomic nuclei. Roentgenium - a new chemical element

    International Nuclear Information System (INIS)

    Ever since the foundation of the GSI, the Darmstadt-based Gesellschaft fuer Schwerionenforschung, in the 1970s, physicists of the Justus-Liebig-University of Giessen have been at the frontiers of research work examining the behaviour of nuclear matter under critical stability conditions. The article in this edition of ''Spiegel der Forschung'', the scientific journal of the university, highlights the results of the last twenty years of research activities with the velocity separator named SHIP, Separator for Heavy Ion Reaction Products. With this instrument, developed by members of the university's II. Institute of Physics and built and operated by members of the GSI in Darmstadt, the scientists were able to generate the six heaviest of the currently known chemical elements, with atomic numbers ranging from 107 to 112. The element with the atomic number 111 will be named ''Roentgenium'', in honour of the famous physicist and Nobel prize winner Wilhelm Conrad Roentgen

  4. analysis of some human-daily - used products and studying the correlation between elemental content and possible health harm using chemical and nuclear analytical techniques

    International Nuclear Information System (INIS)

    radiochemical and chemical techniques have been used for analysis of some human-daily-used products. these techniques were: instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectrometry (ICP-MS). the first technique was used for simultaneously multi-element determination of some trace, minor, and major elements in the analyzed samples, whereas icp-ms was used for analysis of Cd,Cu,Hg, and Pb in some samples. in the present study samples of various products as indicated below were analyzed: 1- samples of various kinds of cosmetic products such as : compact face powder, compact rouge make-up, compact eyeshadow, 2-samples of some common drugs. 3- samples of different kinds of toothpaste, and shaving cream. 4- samples of some mosquitoes exterminators. these samples have been randomly selected from the egyptian market. some of these samples were imported from the world market, and the others were manufactured in Egypt

  5. Chemistry of the superheavy elements.

    Science.gov (United States)

    Schädel, Matthias

    2015-03-13

    The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models. PMID:25666065

  6. Speciation of selected minor and major elements in oil ash I. Operationally defined chemical associations and aqueous speciation

    Energy Technology Data Exchange (ETDEWEB)

    Achilli, M.; Zoboli, A.; Gacs, I.; De Robertis, U.; Bianchi, A. [CISE SpA, Segrate (Italy)

    1997-01-01

    This study is focused on the speciation of selected elements in oil ash. Our efforts were direct primarily to obtain information on the various forms of vanadium, chromium and nickel. One sample was characterized via its total composition and via its capacity for releasing various elements. The latter was estimated by hot water and nitric acid extractions. A rapid cold water extraction technique has been developed and utilized for sample preparation prior to aqueous speciation by high pressure ion chromatography (HPIC). Results of the HPIC measurements, in agreement with electron spin resonance (ESR) investigations performed on the solid sample, indicate that 38% of the vanadium is present as VOSO{sub 4}, 58% of the chromium is Cr{sub 2}(SO{sub 4}){sub 3} and 30% of the nickel is NiSO{sub 4}. The pH and the redox potential values of the cold water extract support the existence of these forms. Results of a generic study with successive fractionation extractions show the probable existence of oxides, associations with organic matter and aluminosilicate minerals. 18 refs., 8 figs., 6 tabs.

  7. Effect of water-chemical regimes and exploitation parameters on the fuel can corrosion and light-water reactor fuel elements security

    International Nuclear Information System (INIS)

    A physico-chemical model of nodal and uniform corrosion of zirconium fuel cans in reactors is proposed. The model takes account of the following physical parameters: values of neutron and thermal fluxes, burnup, temperature, as well as of the water chemistry parameters. The model developed is based on a correlation between zirconium oxide solubility in the coolant and measured values of fuel can corrosion in reactors. Based on the reliability theory, a mathematical model is proposed, connecting the rate of the can corrosion with the fuel element failure intensity at NPPs with RBMK and WWER type reactors

  8. Chemistry of the transactinide elements

    International Nuclear Information System (INIS)

    The experimentally known chemical properties of the transactinide elements 104 and 105, and the experimental techniques used to study these properties on an atom-at-a-time base, are reviewed. The production of transactinides in heavy ion reactions and the specific aspects of chemical separations with single atoms is briefly discussed. The chemical properties of the first two transactinide elements are compared with the lighter element homologs in group 4 and 5 of the Periodic Table and with the expected behaviour obtained from most recent atomic and molecular calculations which take the increasingly strong relativistic effect into account. Elements 104 and 105 behave as transactinide elements and, in general, exhibit properties characteristic of their position in group 4 and 5 of the Periodic Table. However, surprising deviations of the chemical properties from expectations based on simple extrapolations have been observed. It is shown that the chemical properties of the heaviest elements cannot reliably be predicted by simple extrapolations. Prospects to extend our chemical knowledge at the top end of the Periodic Table are discussed. (orig.)

  9. Classification and Hazard Analysis of Dioxins-class Chemicals%二恶英类化学物质的分类及其危害分析

    Institute of Scientific and Technical Information of China (English)

    马德金

    2011-01-01

    二恶英类化学物质 (Dioxins-class chemicals) 对人类乃至生物体的持久毒性危害已经引起全球范围的高度关注和重视,基于大量科技文献中所涉及的科技术语多有混淆的现象,以及目前研究与实践领域中存在的难题,本文就该类物质的规范性分类、危害性分析以及建议予以论述.

  10. Evaluation of Wet Chemical ICP-AES Elemental Analysis Methods using Simulated Hanford Waste Samples-Phase I Interim Report

    International Nuclear Information System (INIS)

    The wet chemistry digestion method development for providing process control elemental analyses of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Melter Feed Preparation Vessel (MFPV) samples is divided into two phases: Phase I consists of: (1) optimizing digestion methods as a precursor to elemental analyses by ICP-AES techniques; (2) selecting methods with the desired analytical reliability and speed to support the nine-hour or less turnaround time requirement of the WTP; and (3) providing baseline comparison to the laser ablation (LA) sample introduction technique for ICP-AES elemental analyses that is being developed at the Savannah River National Laboratory (SRNL). Phase II consists of: (1) Time-and-Motion study of the selected methods from Phase I with actual Hanford waste or waste simulants in shielded cell facilities to ensure that the methods can be performed remotely and maintain the desired characteristics; and (2) digestion of glass samples prepared from actual Hanford Waste tank sludge for providing comparative results to the LA Phase II study. Based on the Phase I testing discussed in this report, a tandem digestion approach consisting of sodium peroxide fusion digestions carried out in nickel crucibles and warm mixed-acid digestions carried out in plastic bottles has been selected for Time-and-Motion study in Phase II. SRNL experience with performing this analytical approach in laboratory hoods indicates that well-trained cell operator teams will be able to perform the tandem digestions in five hours or less. The selected approach will produce two sets of solutions for analysis by ICP-AES techniques. Four hours would then be allocated for performing the ICP-AES analyses and reporting results to meet the nine-hour or less turnaround time requirement. The tandem digestion approach will need to be performed in two separate shielded analytical cells by two separate cell operator teams in order to achieve the nine-hour or less turnaround

  11. Examination of chemical elements partitioning between the γ and γ′ phases in CMSX-4 superalloy using EDS microanalysis and electron tomography

    Directory of Open Access Journals (Sweden)

    Kruk Adam

    2014-01-01

    Full Text Available In the present study, the partition of chemical elements between γ and γ′ phases in CMSX-4 was investigated using EDS microanalysis and electron tomography (FIB-SEM and STEM-EDS methods. The investigation has been performed for the superalloy after standard heat treatment and the ex-service CMSX-4 turbine blade after operation for 12 700 hours and 200 starts in industrial gas turbine. The results have shown that Co, Cr and Re partition to the γ matrix, Ni and W are present in both γ and γ′ phases, while Al, Ti and Ta strongly partition to the γ′ phase. The results show the abilities of new analytical electron microscopy and electron tomography methods to characterize the microstructure and chemical composition of single crystal superalloys at the nanoscale.

  12. Toxicity assessments of nonsteroidal anti-inflammatory drugs in isolated mitochondria, rat hepatocytes, and zebrafish show good concordance across chemical classes

    International Nuclear Information System (INIS)

    To reduce costly late-stage compound attrition, there has been an increased focus on assessing compounds in in vitro assays that predict attributes of human safety liabilities, before preclinical in vivo studies are done. Relevant questions when choosing a panel of assays for predicting toxicity are (a) whether there is general concordance in the data among the assays, and (b) whether, in a retrospective analysis, the rank order of toxicity of compounds in the assays correlates with the known safety profile of the drugs in humans. The aim of our study was to answer these questions using nonsteroidal anti-inflammatory drugs (NSAIDs) as a test set since NSAIDs are generally associated with gastrointestinal injury, hepatotoxicity, and/or cardiovascular risk, with mitochondrial impairment and endoplasmic reticulum stress being possible contributing factors. Eleven NSAIDs, flufenamic acid, tolfenamic acid, mefenamic acid, diclofenac, meloxicam, sudoxicam, piroxicam, diflunisal, acetylsalicylic acid, nimesulide, and sulindac (and its two metabolites, sulindac sulfide and sulindac sulfone), were tested for their effects on (a) the respiration of rat liver mitochondria, (b) a panel of mechanistic endpoints in rat hepatocytes, and (c) the viability and organ morphology of zebrafish. We show good concordance for distinguishing among/between NSAID chemical classes in the observations among the three approaches. Furthermore, the assays were complementary and able to correctly identify “toxic” and “non-toxic” drugs in accordance with their human safety profile, with emphasis on hepatic and gastrointestinal safety. We recommend implementing our multi-assay approach in the drug discovery process to reduce compound attrition. - Highlights: • NSAIDS cause liver and GI toxicity. • Mitochondrial uncoupling contributes to NSAID liver toxicity. • ER stress is a mechanism that contributes to liver toxicity. • Zebrafish and cell based assays are complimentary

  13. Toxicity assessments of nonsteroidal anti-inflammatory drugs in isolated mitochondria, rat hepatocytes, and zebrafish show good concordance across chemical classes

    Energy Technology Data Exchange (ETDEWEB)

    Nadanaciva, Sashi [Compound Safety Prediction, Worldwide Medicinal Chemistry, Pfizer, Inc., Groton, CT 06340 (United States); Aleo, Michael D. [Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340 (United States); Strock, Christopher J. [Cyprotex US, Watertown, MA 02472 (United States); Stedman, Donald B. [Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340 (United States); Wang, Huijun [Computational Sciences, Pfizer Inc., Groton, CT 06340 (United States); Will, Yvonne, E-mail: yvonne.will@pfizer.com [Compound Safety Prediction, Worldwide Medicinal Chemistry, Pfizer, Inc., Groton, CT 06340 (United States)

    2013-10-15

    To reduce costly late-stage compound attrition, there has been an increased focus on assessing compounds in in vitro assays that predict attributes of human safety liabilities, before preclinical in vivo studies are done. Relevant questions when choosing a panel of assays for predicting toxicity are (a) whether there is general concordance in the data among the assays, and (b) whether, in a retrospective analysis, the rank order of toxicity of compounds in the assays correlates with the known safety profile of the drugs in humans. The aim of our study was to answer these questions using nonsteroidal anti-inflammatory drugs (NSAIDs) as a test set since NSAIDs are generally associated with gastrointestinal injury, hepatotoxicity, and/or cardiovascular risk, with mitochondrial impairment and endoplasmic reticulum stress being possible contributing factors. Eleven NSAIDs, flufenamic acid, tolfenamic acid, mefenamic acid, diclofenac, meloxicam, sudoxicam, piroxicam, diflunisal, acetylsalicylic acid, nimesulide, and sulindac (and its two metabolites, sulindac sulfide and sulindac sulfone), were tested for their effects on (a) the respiration of rat liver mitochondria, (b) a panel of mechanistic endpoints in rat hepatocytes, and (c) the viability and organ morphology of zebrafish. We show good concordance for distinguishing among/between NSAID chemical classes in the observations among the three approaches. Furthermore, the assays were complementary and able to correctly identify “toxic” and “non-toxic” drugs in accordance with their human safety profile, with emphasis on hepatic and gastrointestinal safety. We recommend implementing our multi-assay approach in the drug discovery process to reduce compound attrition. - Highlights: • NSAIDS cause liver and GI toxicity. • Mitochondrial uncoupling contributes to NSAID liver toxicity. • ER stress is a mechanism that contributes to liver toxicity. • Zebrafish and cell based assays are complimentary.

  14. Gas chromatographic studies of the heaviest elements

    International Nuclear Information System (INIS)

    Recent experiments are reviewed which used on-line isothermal gas chromatography techniques for studying chemical properties of transactinide elements. Elements 106 (Sg) and 107(Bh) could assigned to groups 6 and 7 of the Periodic Table. The chemical characterization of elements 108 (Hs) and 112 has been prepared. A first attempt to chemically identify element 112 has been unsuccessful. Nevertheless, the chemical isolation of transactinide elements with Z>107 appears feasible. It could also serve to confirm the discovery of SHE decaying to nuclides which have previously been unknown

  15. Nuclear process and the heaviest chemical elements in the magnetic stars

    International Nuclear Information System (INIS)

    Full text : In the base of investigate isotopic shifts in the lines it was obtained that several lanthanides (rare earths) and actinides (Thand U) is present in the atmosphere of magnetic chemical peculiar stars. Isotopic shifts in the lines of the heavy elements in MCP stars point to the fact it is observed mainly the products of rapid neutron capture. Isotopic shifts in the lines of the heavy elements in MCP stars and it is known that large majority chemically elements may be generated by the nuclear reactions, in particular in a stars

  16. Analysis of airborne pesticides from different chemical classes adsorbed on Radiello® Tenax® passive tubes by thermal-desorption-GC/MS.

    Science.gov (United States)

    Raeppel, Caroline; Fabritius, Marie; Nief, Marie; Appenzeller, Brice M R; Briand, Olivier; Tuduri, Ludovic; Millet, Maurice

    2015-02-01

    An analytical methodology using automatic thermal desorption (ATD) and GC/MS was developed for the determination of 28 pesticides of different chemical classes (dichlobenil, carbofuran, trifluralin, clopyralid, carbaryl, flazasulfuron, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, cyprodinil, bromoxynil, fluroxypyr, oxadiazon, myclobutanil, buprofezin, picloram, trinexapac-p-ethyl, ioxynil, diflufenican, tebuconazole, bifenthrin, isoxaben, alphacypermethrin, fenoxaprop and tau-fluvalinate) commonly used in nonagricultural areas in atmospheric samples. This methodology was developed to evaluate the indoor and outdoor atmospheric contamination by nonagricultural pesticides. Pesticides were sampled passive sampling tubes containing Tenax® adsorbent. Since most of these pesticides are polar (clopyralid, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, bromoxynil, fluroxypyr, picloram, trinexapac-p-ethyl and ioxynil), a derivatisation step is required. For this purpose, a silylation step using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MtBSTFA) was added before thermal desorption. This agent was chosen since it delivers very specific ions on electronic impact (m/z = M-57). This method was established with special consideration for optimal thermal desorption conditions (desorption temperature, desorb flow and duration; trap heating duration and flow; outlet split), linear ranges, limits of quantification and detection which varied from 0.005 to 10 ng and from 0.001 to 2.5 ng, respectively, for an uncertainty varied from 8 to 30 %. The method was applied in situ to the analysis of passive tubes exposed during herbicide application to an industrial site in east of France. PMID:25205153

  17. 3D Chemical and Elemental Imaging by STXM Spectrotomography

    International Nuclear Information System (INIS)

    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.

  18. Origin of light elements

    International Nuclear Information System (INIS)

    A brief review on the state of the problem of occurrence of light elements, physics of shearing reactions and nucleosynthesis, caused by the observed fluxes of galactic cosmic rays is presented. Special attention is paid to 7Li nucleosynthesis, revealing interesting aspects of star physics, the problem of the effect of low-energy cosmic ray flux, strongly modulated by solar wind and solar magnetic activity, nucleosynthesis in red giants, explosions of novae and early stages of the Universe evolution which are of particular interest among them. The conclusion is made, that light elements Li, Be and B present a unique instrument for the analysis of cosmologic problems, as well as for the comprehension of the physics of cosmic rays and chemical evolution of galaxies

  19. Trace Elements and Physico-Chemical Quality of the Well Waters in Mahitsy, Province of Antananarivo, Madagascar

    International Nuclear Information System (INIS)

    The proposed study area of Mahitsy is located in the province of Antananarivo. Only 14.38% of the population in the rural zone has access to safe drinking water. Most of human population use wells or springs as the main source of drinking water. Wells are generally less than 20 meters deep and they are not properly sealed. Well waters investigated in January 2004 have a very large range of trace constituent and chemical composition in the zone of interest. Manganese concentrations range is 8μg.L-1-1115 μg.L-1 and concentrations of barium vary in the range of 55μg.L-1- 4967 μg.L-1. 67% of monitored well waters are of manganese concentration higher than 50μg.L-1 and 44% contain barium with a concentration higher than 700μg.L-1. Total dissolved solids vary between 8 mg.L-1 and 881 mg.L-1 and well water pHs are acidic (4.28 - 5.94). Nitrate concentrations monitored in Mahitsy groundwaters show that, 54% of the well water samples exceed 50 mg.L-1(WHO guidelines value) and 84% exceed 13.5 mg.L-1 (indicative value of human activities). The nitrate content ranges from 4 to 489 mg.L-1. Groundwater nitrate correlates positively with chloride and potassium. That would suggest that the high content of nitrate may result from the septic tank, the cesspool and the animal wastes storage, located next to the well. However, people draw water from groundwater for domestic purposes, as the water infrastructure remains undeveloped in the studied area. The measurement of trace constituents are performed using Total Relflection X-ray Fluorescence (TXRF) analytical method and the major ions are determined by Ion Chromatograph (IC) system.

  20. The new model of chemical evolution of r-process elements based on the hierarchical galaxy formation. I. Ba and Eu

    International Nuclear Information System (INIS)

    We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy r-process elements, Ba and Eu, of extremely metal-poor (EMP) stars and give constraints on their astronomical sites. Our models take into account changes of the surface abundances of EMP stars by the accretion of interstellar medium (ISM). We also consider metal-enrichment of intergalactic medium by galactic winds and the resultant pre-enrichment of proto-galaxies. The trend and scatter of the observed r-process abundances are well reproduced by our hierarchical model with ∼10% of core-collapse supernovae in low-mass end (∼10 M ☉) as a dominant r-process source and the star formation efficiency of ∼10–10 yr–1. For neutron star mergers as an r-process source, their coalescence timescale has to be ∼107 yr, and the event rates ∼100 times larger than currently observed in the Galaxy. We find that the accretion of ISM is a dominant source of r-process elements for stars with [Ba/H] < –3.5. In this model, a majority of stars at [Fe/H] < –3 are formed without r-process elements, but their surfaces are polluted by the ISM accretion. The pre-enrichment affects ∼4% of proto-galaxies, and yet, is surpassed by the ISM accretion in the surface of EMP stars.

  1. Seawater-like trace element signatures (REE + Y) of Eoarchaean chemical sedimentary rocks from southern West Greenland, and their corruption during high-grade metamorphism

    Science.gov (United States)

    Friend, C. R. L.; Nutman, A. P.; Bennett, V. C.; Norman, M. D.

    2008-02-01

    Modern chemical sediments display a distinctive rare earth element + yttrium (REE + Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN = shale normalised) that is related to precipitation from circumneutral to high pH waters with solution complexation of the REEs dominated by carbonate ions. This is often interpreted as reflecting precipitation from surface waters (usually marine). The oldest broadly accepted chemical sediments are c. 3,700 Ma amphibolite facies banded iron-formation (BIF) units in the Isua supracrustal belt, Greenland. Isua BIFs, including the BIF international reference material IF-G are generally considered to be seawater precipitates, and display these REE + Y patterns (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004). Greenland Eoarchaean BIF metamorphosed up to granulite facies from several localities in the vicinity of Akilia (island), display REE + Y patterns identical to Isua BIF, consistent with an origin by chemical sedimentation from seawater and a paucity of clastic input. Furthermore, the much-debated magnetite-bearing siliceous unit of “earliest life” rocks (sample G91/26) from Akilia has the same REE + Y pattern. This suggests that sample G91/26 is also a chemical sediment, contrary to previous assertions (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004), and including suggestions that the Akilia unit containing G91/26 consists entirely of silica-penetrated, metasomatised, mafic rock (Fedo and Whitehouse 2002a). Integration of our trace element data with those of Bolhar et al. (Earth Planet Sci Lett 222:43 60, 2004) demonstrates that Eoarchaean siliceous rocks in Greenland, with ages from 3.6 to 3.85 Ga, have diverse trace element signatures. There are now geographically-dispersed, widespread examples with Isua BIF-like REE + Y signatures, that are interpreted as chemically unaltered, albeit metamorphosed, chemical sediments. Other samples retain remnants of LREE depletion but

  2. Carbon black vs. black carbon and other airborne materials containing elemental carbon: Physical and chemical distinctions

    International Nuclear Information System (INIS)

    Airborne particles containing elemental carbon (EC) are currently at the forefront of scientific and regulatory scrutiny, including black carbon, carbon black, and engineered carbon-based nanomaterials, e.g., carbon nanotubes, fullerenes, and graphene. Scientists and regulators sometimes group these EC-containing particles together, for example, interchangeably using the terms carbon black and black carbon despite one being a manufactured product with well-controlled properties and the other being an undesired, incomplete-combustion byproduct with diverse properties. In this critical review, we synthesize information on the contrasting properties of EC-containing particles in order to highlight significant differences that can affect hazard potential. We demonstrate why carbon black should not be considered a model particle representative of either combustion soots or engineered carbon-based nanomaterials. Overall, scientific studies need to distinguish these highly different EC-containing particles with care and precision so as to forestall unwarranted extrapolation of properties, hazard potential, and study conclusions from one material to another. -- Highlights: •Major classes of elemental carbon-containing particles have distinct properties. •Despite similar names, carbon black should not be confused with black carbon. •Carbon black is distinguished by a high EC content and well-controlled properties. •Black carbon particles are characterized by their heterogenous properties. •Carbon black is not a model particle representative of engineered nanomaterials. -- This review demonstrates the significant physical and chemical distinctions between elemental carbon-containing particles e.g., carbon black, black carbon, and engineered nanomaterials

  3. Mining Natural-Products Screening Data for Target-Class Chemical Motifs.

    Science.gov (United States)

    Coma, Isabel; Bandyopadhyay, Deepak; Diez, Emilio; Ruiz, Emilio Alvarez; de los Frailes, Maria Teresa; Colmenarejo, Gonzalo

    2014-06-01

    In this article, we describe two complementary data-mining approaches used to characterize the GlaxoSmithKline (GSK) natural-products set (NPS) based on information from the high-throughput screening (HTS) databases. Both methods rely on the aggregation and analysis of a large set of single-shot screening data for a number of biological assays, with the goal to reveal natural-product chemical motifs. One of them is an established method based on the data-driven clustering of compounds using a wide range of descriptors,(1)whereas the other method partitions and hierarchically clusters the data to identify chemical cores.(2,3)Both methods successfully find structural scaffolds that significantly hit different groups of discrete drug targets, compared with their relative frequency of demonstrating inhibitory activity in a large number of screens. We describe how these methods can be applied to unveil hidden information in large single-shot HTS data sets. Applied prospectively, this type of information could contribute to the design of new chemical templates for drug-target classes and guide synthetic efforts for lead optimization of tractable hits that are based on natural-product chemical motifs. Relevant findings for 7TM receptors (7TMRs), ion channels, class-7 transferases (protein kinases), hydrolases, and oxidoreductases will be discussed. PMID:24518065

  4. Influence of radiation on some physico-chemical properties of gum acacia. Mitigation of degradation by different class of antioxidants in LDPE expose to ionizing radiations

    International Nuclear Information System (INIS)

    Controlling of degradation in polysaccharide is also gaining impetus from commercial point of view. Comprehensive studies on the influence of ionizing radiation on the physico-chemical properties of polysaccharides are very important for their applications in different industries. The effect of gamma radiation on gum acacia has been studied and its effect on some physico-chemical properties, as measured by UV spectroscopy and viscometry has been discussed. The gum samples are irradiated in the range of 5 kGy to 25 kGy both in air and vacuum. Samples irradiated under vacuum shows colour stability while viscosity remain unaffected. (author)

  5. Mobility of major and trace elements in andosols from Iceland: correlating extent of chemical weathering with climatic conditions at soil formation sites

    Science.gov (United States)

    Oskarsson, Birgir V.; Riishuus, Morten S.; Arnalds, Olafur

    2010-05-01

    Element mobility within volcanic soil profiles developed in diverse climatic conditions in Iceland is assessed. Soils were selected from areas with good monitoring of annual temperature and precipitation and the degree of weathering and elemental behavior was compared. Most soils in Iceland develop in parent materials of volcanic origin, including a variety of basaltic and andesitic tephras, hyaloclastites and glacial tillites. Most Icelandic soils are subject to considerable flux of eolian deposition and in times receive tephra ejecta from volcanic eruptions. In this study, samples were carefully extracted from brown and gleyic andosol horizons for major and trace element analysis. Each horizon is representative of a pedogenetic stage. Preliminary results show that the major elements TiO2, Al2O3 and Fe2O3 (T) (mean wt% = 3.4, 19.2, 17.3) appear immobile relative to the parent material (p.m. mean wt% = 1.6, 14.6, 10.9) and are found enriched within more mature horizons. The base cations MgO, CaO and Na2O (mean wt% = 4.11, 7.23, 1.8) are depleted in these horizons (p.m. mean wt% = 9.1, 11.8, 2.0) showing mobilization during pedogenesis. The trace elements reveal no strong enrichment/depletion trend with a range of mobility from mobile to immobile Rb, Zn, Y, Sr, Ba, Ni, La, Cr, Cu, Nd, V, Zr and Nb. Soils developed in colder and dryer climatic conditions in Iceland (MAT = -1°C and MAP = 1000mm) show higher levels of weathering (CIA-K = 50-65) and element mobilization. The parent materials have a CIA-K weathering index of 37. The relationship of the covariance of the climate parameters with extent of chemical weathering may be quantified as climofunctions to deliver proxy climate data under cool to subarctic conditions. Our results may yield reasonable tools for determining past climate variations from weathered tephras found as paleosols in the Neogene lava piles of Iceland and other volcanic provinces.

  6. Influence of chemical composition and alloying elements on microdefects and electron density in Ni-Al alloys

    Institute of Scientific and Technical Information of China (English)

    邓文; 黄宇阳; 吴道宏; 熊良钺; 王淑荷; 郭建亭

    2002-01-01

    Positron lifetime spectra have been measured in binary Ni-Al alloys with different chemical composition and NiAl alloys doped with Cr, Zr, Fe and Mg. The results indicate that in B2-NiAl and Ll2-Ni3Al alloys, some of the valance electrons of Ni and Al atoms are localized, which leads to a lower free electron density of the alloy. The mean free electron density of the binary Ni-Al alloy decreases with increasing Al content. The open volume of defects on grain boundary of the Ni3Al is larger than that of monovacancy or dislocation. Structural vacancies and microvoids are found in B2-NiAl alloys with Al content above 45%(mole fraction), and the concentration of the vacancies and open volume of microvoids will increase with higher Al content. The addition of Cr, Zr and Fe into a NiAl alloy can increase its mean free electron density and reduce the open volume of defects on its grain boundary, while with addition of Mg into the NiAl alloy, its mean free electron density decreases and open volume of boundary defects increases.

  7. Synthesis and evaluation of germanic organometallic compounds as precursors for chemical vapor deposition (CVD) and for obtaining nanoparticles of elemental germanium

    International Nuclear Information System (INIS)

    The interest in the development of materials that have applications in areas such as electronics or biomarkers has affected the synthesis of new compounds based on germanium. This element has two states of common oxidation, +4 and +2, of them, the +2 oxidation state is the least studied and more reactive. Additionally, compounds of germanium (II) have similarities to carbenes in terms Lewis'acid base chemistry. The preparation of compounds of germanium (II) with ligands β-diketiminates has made possible the stabilization of new chemical functionalities and, simultaneously, it has provided interesting thermal properties to develop new methods of preparation of materials with novel properties. The preparation of amides germanium (II) L'Ge (NHPh) [1, L'= {HC (CMeN-2,4,6-Me3C6H2)2}-], L'Ge (4-NHPy) [2], L'Ge (2-NHPy) [3] and LGe(2-NHPy) [4, L = {HC (CMeN-2,6-iPr2C6H3)2]-] are presented, the chemical and structural composition was determined by using techniques such as nuclear magnetic resonance (1H, 13C), elemental analysis, melting point, infrared spectroscopy, X-ray diffraction of single crystal and thermogravimetric analysis (TGA). The TGA has demonstrated that 1-4 experience a thermal decomposition, therefore, these compounds could be considered as potential starting materials for the obtaining of germanium nitride (GeNx). Certainly, the availability of coordinating nitrogen atoms in the chemical composition in 2-4 have been interesting given that it could act as ligands in reactions with transition metal complexes. Thus, relevant information to molecular level could be obtained for some reactions and interactions that have used similar link sites in surface chemistry, for example, the chemical functionalization of silicon and germanium substrate. Additionally, the synthesis and structural characterization of germanium chloride compound (II) LGeCl [5, L' = HC{(CMe) (N-2,6-Me2C6H3)}2-] is reported, which subsequently could be used to

  8. Production of transuranium elements

    International Nuclear Information System (INIS)

    The Radiochemical Engineering Development Center (REDC) has the programmatic responsibility for the Department of Energy's Transuranium Element Program. Principle elements from the program are einsteinium, berkelium, and fermium. Targets containing curium oxide mixed with aluminum powder are fabricated by the REDC and irradiated in the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor. Following an irradiation period of 6-12 months, targets are returned to the REDC for chemical processing. Processing operations consists of aluminum dejacketing in a caustic-nitrate solution, filtration, acid dissolution, solvent extraction, anion exchange, and finally a cation exchange to recover the actinides. The processing operations take place in heavily shielded hot cell facilities and all operations are carried out remotely. The chemistry for the separations has been well established over the 26-yr. operating life of the facility

  9. The Class of '34

    OpenAIRE

    Cairney, Richard

    1995-01-01

    The Great Depression raged, governments were beleaguered, the unemployment rate stood at 30%, scurvy stalked the poor and no one was immune to contagious diseases such as scarlet fever, polio and measles when the University of Alberta School of Medicine's Class of '34 graduated. For four alumni who recently gathered in Edmonton—Drs. Morley Hodgson, Melvin Gaudin, John McLurg and Edmund Cairns—their 60th-anniversary reunion was a time to recall the changes they have witnessed in medicine, incl...

  10. Development of a deep-sea laser-induced breakdown spectrometer for in situ multi-element chemical analysis

    Science.gov (United States)

    Thornton, Blair; Takahashi, Tomoko; Sato, Takumi; Sakka, Tetsuo; Tamura, Ayaka; Matsumoto, Ayumu; Nozaki, Tatsuo; Ohki, Toshihiko; Ohki, Koichi

    2015-01-01

    Spectroscopy is emerging as a technique that can expand the envelope of modern oceanographic sensors. The selectivity of spectroscopic techniques enables a single instrument to measure multiple components of the marine environment and can form the basis for versatile tools to perform in situ geochemical analysis. We have developed a deep-sea laser-induced breakdown spectrometer (ChemiCam) and successfully deployed the instrument from a remotely operated vehicle (ROV) to perform in situ multi-element analysis of both seawater and mineral deposits at depths of over 1000 m. The instrument consists of a long-nanosecond duration pulse-laser, a spectrometer and a high-speed camera. Power supply, instrument control and signal telemetry are provided through a ROV tether. The instrument has two modes of operation. In the first mode, the laser is focused directly into seawater and spectroscopic measurements of seawater composition are performed. In the second mode, a fiber-optic cable assembly is used to make spectroscopic measurements of mineral deposits. In this mode the laser is fired through a 4 m long fiber-optic cable and is focused onto the target's surface using an optical head and a linear stage that can be held by a ROV manipulator. In this paper, we describe the instrument and the methods developed to process its measurements. Exemplary measurements of both seawater and mineral deposits made during deployments of the device at an active hydrothermal vent field in the Okinawa trough are presented. Through integration with platforms such as underwater vehicles, drilling systems and subsea observatories, it is hoped that this technology can contribute to more efficient scientific surveys of the deep-sea environment.

  11. Processing of spent Ni-MH batteries for the recovery of cobalt, nickel and rare earth elements bearing materials by means of a chemical and electrochemical sequential process

    Science.gov (United States)

    Delvasto, P.; Orta Rodríguez, R.; Blanco, S.

    2016-02-01

    Rechargeable Ni-MH batteries contain strategic metal values which are worth to be recovered. In the present work, a preliminary sequential chemical and electrochemical procedure is proposed, in order to reclaim materials bearing Ni, Co and rare earth elements (REE) from Ni-MH spent batteries. Initially, spent batteries are disassembled to separate the electrode materials (anode and cathode), which are then leached with an aqueous solution of 5w% sulphuric acid. The metal content of this solution is checked by atomic absorption spectrometry techniques. The obtained solution is pH-adjusted (with NaOH), until pH is between 4.0 and 4.3; then, it is heated up to 70°C to precipitate a rare earth elements sulphate (Nd, La, Pr, Ce), as determined by means of x-ray fluorescence techniques. The solids-free solution is then electrolyzed, in order to recover a Ni-Co alloy. The electrolysis conditions were established through a cyclic voltammetry technique.

  12. Meteorological Situations in 2007 and their Implications for the Cycling of Selected Chemical Elements in a Central Bohemian Forested Catchment

    Czech Academy of Sciences Publication Activity Database

    Kubínová, Petra; Drahota, Petr; Fišák, Jaroslav; Skřivan, Petr; Rohovec, Jan

    2009-01-01

    Roč. 4, č. 4 (2009), s. 149-158. ISSN 1801-5395 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z30420517 Keywords : precipitation * forested catchment * elements * mass balance s Subject RIV: DD - Geochemistry http://www.agriculturejournals.cz/uniqueFiles/13036.pdf

  13. Syntheses, structural characterizations and physico-chemical properties of tetravalent elements fluorides; Syntheses, caracterisations structurales et physico-chimiques de fluorures d'elements tetravalents

    Energy Technology Data Exchange (ETDEWEB)

    Mapemba Moulakou, E

    2007-07-15

    This work initially was devoted to the study of phase relationship in the ternary system KF-MnF{sub 2}-ZrF{sub 4}. During the study in this system the compound of KMn.ZrF{sub 7} has been evidenced. The crystal structure determination allowed to show the opportunity to substitute two rare earths Ln{sup 3+} for the couple Zr{sup 4+} and Mn{sup 2+} without any charge compensation. This study also allowed to clarify the phase-relationship in the binary system KF-ZrF{sub 4}. The study of the insertion of lithium ions in tetravalent lanthanides or actinides fluorides led to the obtention of a new phase Li{sub 5,5}Ce{sub 12}F{sub 50}. The crystal structure determination revealed the simultaneous presence of Ce{sup 4+} in 8 and 9-coordination building tetra-meric units as well as Ce{sup 3+} and Ce{sup 3+}/Ce{sup 4+} (in statistical distribution) encompassed in isolated in 8-coordination polyhedra. In the light of this result we have revised the study of the LiM{sub 4}F{sub 17} phases initially reported as belonging to the binary systems LiF-MF{sub 4} (M = Ce, U, Th) and shown that these phases were in fact mixed valence (III/IV) fluorinated compounds. A new method of mixed valence fluorides synthesis by electrochemical intercalation of lithium ions in the host matrix has been developed. To this aim containing Ce, Tb, U, Th have been tested. Finally this research work has been extended to the study of fluoro-zirconates and fluoro-terbates of formula LiLniMF{sub 8} (M = Zr and Tb). The structural characterization of these LiLnMF{sub 8} compounds allowed to show the existence of structural relationships with the fluorides LiNaY{sub 2}F{sub 8}. LiNaYb{sub 2}F{sub 8} and BaY{sub 2}F{sub 8}. These compounds LiLnMF{sub 8} (M = Zr and Tb) exhibit open structures susceptible to enhance the diffusion of the alkaline ions. Thus the intercalation and de-intercalation of the alkaline ions in the LiY TbF{sub 8} host matrix allowed the obtention of new mixed valence fluorinated compounds

  14. The New Model of Chemical Evolution of r-process Elements Based on The Hierarchical Galaxy Formation I: Ba and Eu

    CERN Document Server

    Komiya, Yutaka; Suda, Takuma; Fujimoto, Masayuki Y

    2014-01-01

    We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy r-process elements, Ba and Eu, of extremely metal-poor (EMP) stars and give constraints on their astronomical sites. Our models take into account changes of the surface abundances of EMP stars by the accretion of interstellar matter (ISM). We also consider metal-enrichment of intergalactic medium (IGM) by galactic winds and the resultant pre-enrichment of proto-galaxies. The trend and scatter of the observed r-process abundances are well reproduced by our hierarchical model with $\\sim 10\\%$ of core-collapse supernovae in low-mass end ($\\sim 10M_{\\odot}$) as a dominant r-process source and the star formation efficiency of $\\sim 10^{-10} \\hbox{yr}^{-1}$. For neutron star mergers as an r-process source, their coalescence timescale has to be $ \\sim 10^7$yrs, and the event rates $...

  15. Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Zakrzewska-Koltuniewicz, Grażyna, E-mail: g.zakrzewska@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Herdzik-Koniecko, Irena [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Cojocaru, Corneliu [Institute of Macromolecular Chemistry “Petru Poni”, Aleea Grigore Ghica Voda, nr. 41A, 700487 Iasi (Romania); Chajduk, Ewelina [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland)

    2014-06-30

    Highlights: • The experimental design for optimization of leaching process of uranium from low-grade ores was applied. • Multi-objective optimization method based on desirability approach was employed. • The recovery of associated metals like vanadium, molybdenum and lanthanides was considered. • The effects of factors were identified by 3-D surface plots. • The optimum condition for valuable metals: P = 5 bar, T = 120 °C and t = 90 min has been determined. - Abstract: The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P = 5 bar, T = 120 °C and t = 90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th)

  16. Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore

    International Nuclear Information System (INIS)

    Highlights: • The experimental design for optimization of leaching process of uranium from low-grade ores was applied. • Multi-objective optimization method based on desirability approach was employed. • The recovery of associated metals like vanadium, molybdenum and lanthanides was considered. • The effects of factors were identified by 3-D surface plots. • The optimum condition for valuable metals: P = 5 bar, T = 120 °C and t = 90 min has been determined. - Abstract: The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P = 5 bar, T = 120 °C and t = 90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th)

  17. Chemistry of the heaviest elements

    International Nuclear Information System (INIS)

    Studies of the chemical properties of the elements at the uppermost end of the periodic table are discussed. Some historical perspective is given, but major emphasis is on recent studies. Isotopes of these elements are short-lived and, therefore, must be studied near the site of production. They must be produced with charged-particle beams at accelerators rather than via neutron capture. The use of radioactive heavy actinide targets is often required and the number of atoms produced is so small that any chemistry to be performed must be done on an ''atom-at-a-time'' basis. Furthermore, a knowledge of their nuclear properties is required in order to identify and detect them. To date, both gas and aqueous phase properties of elements as heavy as element 104 (rutherfordium) and element 105 (hahnium) have been investigated, even though their longest-lived known isotopes have half-lives of only 65 and 35 seconds, respectively. The experimental results show that their chemical properties cannot be simply extrapolated from the known properties of their lighter homologs in the periodic table, emphasizing the importance of obtaining additional experimental information for the heaviest elements to compare with predictions and help assess the influence of relativistic effects. The feasibility of the extension of chemical studies to still heavier elements is also discussed. (orig.)

  18. [Internal initiation of translation in eukaryotes. Chemical probing of the encephalomyocarditis virus RNA IRES-element in the 48S preinitiation complex].

    Science.gov (United States)

    Boroviagin, A V; Ezrokhi, M V; Shatskiĭ, I N

    1995-01-01

    Using in vitro T7 polymerase system, the transcript containing the IRES-element (nts 315-833), and the initial part of the coding sequence of encephalomyocarditis virus (EMCV) RNA (nts 834-1155) was prepared. Its complex with the 40S ribosomal subunit (48S preinitiation complex) was then isolated by sucrose gradient sedimentation from ascites carcinoma Krebs2 cell extracts after preincubation with the transcript. The complex was treated with dimethylsulphate (DMS), a common reagent for chemical probing of A and C residues in single-stranded RNA regions. The modified nucleotides were identified by primer extension inhibition analysis in reverse transcription reaction. The pattern of modification of the 48S complex was compared with that for the corresponding free mRNP. Multiple protection of A residues against DMS modification was found in the domains of the IRES-element proximal to the initiation AUG codon (nt 834-836). The mechanism of internal translational initiation of EMCV RNA and other picornaviral RNAs is discussed. PMID:8552069

  19. Hierarchical Classes Modeling of Rating Data

    Science.gov (United States)

    Van Mechelen, Iven; Lombardi, Luigi; Ceulemans, Eva

    2007-01-01

    Hierarchical classes (HICLAS) models constitute a distinct family of structural models for N-way N-mode data. All members of the family include N simultaneous and linked classifications of the elements of the N modes implied by the data; those classifications are organized in terms of hierarchical, if-then-type relations. Moreover, the models are…

  20. PSSP-RFE: accurate prediction of protein structural class by recursive feature extraction from PSI-BLAST profile, physical-chemical property and functional annotations.

    Directory of Open Access Journals (Sweden)

    Liqi Li

    Full Text Available Protein structure prediction is critical to functional annotation of the massively accumulated biological sequences, which prompts an imperative need for the development of high-throughput technologies. As a first and key step in protein structure prediction, protein structural class prediction becomes an increasingly challenging task. Amongst most homological-based approaches, the accuracies of protein structural class prediction are sufficiently high for high similarity datasets, but still far from being satisfactory for low similarity datasets, i.e., below 40% in pairwise sequence similarity. Therefore, we present a novel method for accurate and reliable protein structural class prediction for both high and low similarity datasets. This method is based on Support Vector Machine (SVM in conjunction with integrated features from position-specific score matrix (PSSM, PROFEAT and Gene Ontology (GO. A feature selection approach, SVM-RFE, is also used to rank the integrated feature vectors through recursively removing the feature with the lowest ranking score. The definitive top features selected by SVM-RFE are input into the SVM engines to predict the structural class of a query protein. To validate our method, jackknife tests were applied to seven widely used benchmark datasets, reaching overall accuracies between 84.61% and 99.79%, which are significantly higher than those achieved by state-of-the-art tools. These results suggest that our method could serve as an accurate and cost-effective alternative to existing methods in protein structural classification, especially for low similarity datasets.

  1. Use of selective chemical extractions as a strategy for the risk assessment in sites with a high level of potentially toxic elements

    Science.gov (United States)

    Pérez-Sirvent, Carmen; Martinez Sanchez, Maria Jose; Garcia Lorenzo, Maria Luz; Hernandez Perez, Carmen; Molina Ruiz, Jose; Bech, Jaume

    2016-04-01

    The present study deals with the geochemical fractions of Pb, Cd, Zn and As present on profiles using chemical simple extraction process. This work was conducted on Portman Bay, a site located in the SE Spain and strongly affected by mining activities. Four simple extractions were applied to selected samples in order to evaluate the potential mobility of metals. X-ray diffraction (XRD) and scanning electron microscopy coupled to with an energy-dispersion spectrometry (SEM-EDS) were applied for the characterisation of both the samples and the residues remaining after each extraction, providing additional information about the sediment phases carrying the elements studied. Soil pollution assessment was carried out using the contamination factor (CF) and the pollution load index (PLI) for total contents, and indicators of mobility for each extraction: natural mobility indicator (NMI), acid mine drainage mobility indicator (AMI), oxic mobility indicator (OMI) and anoxic mobility indicator (ANMI). The results obtained after the extractions suggested that the highest PTEs content were extracted in the acidic medium. The mineralogical composition is an important factor that should be taken into account in the evaluation of PTEs mobility, firstly because the mineral phases react differently in the proposed situations depending on their chemical nature, and secondly, because the presence of a particular phase (with different degree of reactivity) depends on the degree of weathering.

  2. Application of INAA for chemical quality control analysis of C-C composite and high purity graphite by determining trace elemental concentrations

    International Nuclear Information System (INIS)

    Carbon based materials like graphite and C-C composites are used for various scientific and technological applications. Owing to its low neutron capture cross section and good moderating properties, graphite is used as a moderator or reflector in nuclear reactors. For high temperature reactors like CHTR, graphite and C-C composites are proposed as structural materials. Studies are in progress to use C-C composites as prospective candidate instead of graphite due to their excellent mechanical and thermal properties. The advantage of carbon-carbon composite is that the microstructure and the properties can be tailor made. Impurities like rare earth elements and neutron poisons which have high neutron absorption cross section and elements whose activation products of have longer half-lives like 60Co (5.27 y), 65Zn (244.3 d) and 59Fe (44.5 d) are not desired in structural materials. For chemical quality control (CQC) it is necessary to evaluate accurately the impurity concentrations using a suitable non-destructive analytical technique. In the present work, two carbon/carbon composite samples and two high purity graphite samples were analyzed by Instrumental Neutron Activation Analysis (INAA) using high-flux reactor neutrons. Samples, sealed in Al foil, were irradiated in tray-rod position of Dhruva reactor, BARC at a neutron flux of ∼ 5 x 1013cm-2s-1. Radioactive assay was carried out using high resolution gamma ray spectrometry using 40% HPGe detector

  3. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  4. Absorption of metals and characterization of chemical elements present in three species of Gracilaria (Gracilariaceae Greville: a genus of economical importance

    Directory of Open Access Journals (Sweden)

    Angela P. Tonon

    2011-04-01

    Full Text Available Gracilaria Greville is a genus of seaweed that is economically explored by the cosmetic, pharmaceutical and food industries. One of the biggest problems associated with growing Gracilaria is the discharge of heavy metals into the marine environment. The absorption of heavy metals was investigated with the macroalga Gracilaria tenuistipitata Zhang et Xia, cultivated in a medium containing copper (Cu and cadmium (Cd. In biological samples, EC50 concentrations of 1 ppm for cadmium and 0.95 ppm for copper were used. These concentrations were based on seaweed growth curves obtained over a period of six days in previous studies. ICP-AES was used to determine the amount of metal that seaweeds absorbed during this period. G. tenuistipitata was able to bioaccumulate both metals, about 17% of copper and 9% of cadmium. Basal natural levels of Cu were found in control seaweeds and in G. tenuistipitata exposed to Cd. In addition, the repertoire of other important chemical elements, as well as their concentrations, was determined for G. tenuistipitata and two other important seaweeds, G. birdiae Plastino & Oliveira and G. domingensis (Kützing Sonder ex Dickie, collected in natural environments on the Brazilian shore.

  5. Gas phase chemistry studies of superheavy elements

    International Nuclear Information System (INIS)

    The present status of the chemical properties investigation for superheavy elements was described in this paper. The synthesis of superheavy elements and the experimental techniques used in studies on the gas phase chemistry of superheavy elements were briefly introduced. The current experimental studies about the gas-chromatography of Rf, Db, Sg, Bh, Hs and element 112 were discussed in detail. Finally, the development of synthesis of superheavy elements and the study on gas phase chemical properties of superheavy elements in China were prospected. (authors)

  6. Analysis of connection element classes and locations and of some structural requirements for the mounting of different superstructure types on transport vehicles

    Directory of Open Access Journals (Sweden)

    Zoran Đ. Majkić

    2011-04-01

    Full Text Available The paper presents the basic requirements for transport vehicles. A special request regarding the adaptation of transport vehicles for the transport of various types of cargo was taken into consideration. Superstructures and the situation arising after mounting superstructures on wheeled transport vehicles were analyzed and the following was described: console coupling, stirrups, simplex elastic coupling, two-way elastic and rigid connection elements. Vehicle torsional elasticity is provided by a proper choice of the type of connection between the superstructure and the vehicle chassis. Applying the instructions of vehicle manufacturers for using appropriate connections between the truck superstructure and the vehicle chassis provides positive torsional elasticity of the vehicle. The paper gives the general recommendations of the Volvo, Mercedes and Renault transport vehicle producers for the use of particular connection types of locations as well as structural requirements for the mounting of concrete mixers, tippers and truck tanks on their vehicles. Introduction Achieving a high level of transport effectiveness depends on a number of factors. One of the most important ones is the possibility to increase the payload share in the gross vehicle weight. This share depends on the net vehicle weight, a method of coupling the truck superstructure with the chassis frame as well as on the truck superstructure construction. Realization of this requirement is of significant importance, particularly for large business systems since it results in the reduction of number of necessary vehicles, more economic fleet maintenance and the fleet capacity increase. It is also relatively easy to adapt the vehicle for the transportation of other loads, depending on user's current needs. The adaptation is correctly performed if manufacturer's recommendations are followed during the mounting of the superstructure on the chassis. This paper gives the analysis of the

  7. Factors controlling the chemical composition of colloidal and dissolved fractions in soil solutions and the mobility of trace elements in soils

    Science.gov (United States)

    Gangloff, Sophie; Stille, Peter; Schmitt, Anne-Désirée; Chabaux, François

    2016-09-01

    The objectives of this study were to determine the processes and physico-chemical conditions that affect the composition of the soil solutions of a forest soil and to elucidate their impact on the transport of major and trace elements through the colloidal (0.2 μm to 5 kDa) and dissolved (soil. All experiments were performed with soil solutions obtained using lysimeter plates situated on an experimental spruce parcel of the Strengbach catchment (Northeastern France). The surface samples filtered at 0.2 μm facilitated the examination of the influence of litter decomposition on the chemical composition of the upper soil solutions. The impact of the soils biogeochemical conditions (pH, moisture, temperature, oxic or anoxic conditions) on litter decomposition was also examined. More particularly, the increase in NH4+ and NO2- compounds in some of the soil solutions points to denitrification processes in an anoxic environment. Thus, under anoxic conditions, the soil solution is enriched in Ca, P, Mn and Zn, whereas under oxic conditions it is enriched in Al and Fe. The physico-chemical conditions are more seasonally dependent in the upper soil horizons than in the deeper ones and have an impact on the variability of the chemical composition of the soil solutions. The colloidal and dissolved fractions of the soil solutions were obtained by tangential flow ultra-filtration. The experimental results reveal that nutrients, such as NO3- and P, are primarily in the dissolved fraction and consequently bioavailable; secondary minerals may be dissolved and/or precipitate in the colloidal fraction, such as pyromorphite (Pb5(PO4)3(OH, Cl, F)). The results further indicate that microbial activity influences the composition of the colloidal and dissolved fractions, and possibly enriches the colloidal fraction in Ca, Mn and P, diminishes the concentrations of Pb, V, Cr and Fe in the dissolved fraction, and changes the structure of organic carbon (OC). These results are important

  8. A new class of spontaneously polarized materials

    DEFF Research Database (Denmark)

    Field, David; Plekan, Oksana; Cassidy, Andrew;

    2011-01-01

    Very large electric fields form spontaneously within films of seemingly prosaic chemicals such as nitrous oxide or propane.We describe how the discovery of this unexpected phenomenon took place and how we attempt to understand the nature of the new class of spontaneously polarized materials...

  9. Raradox of class description

    Institute of Scientific and Technical Information of China (English)

    吕光

    2004-01-01

    We have a more active class atmophere, but more passive self-study situations. We are too talktive when we should bury ourselves in books, but too less efficient when we spend too much time. We complain teachers

  10. Packing element of a packer

    Energy Technology Data Exchange (ETDEWEB)

    Safin, V.A.

    1982-01-01

    The packing element of a packer is proposed which consists of an elastic core and outer layer made of plastic sealing material. It is distinguished by the fact that in order to facilitate removal of the packing element from the site of installation, the outer layer has a sublayer made of polymer material which is chemically inactive in relationship to the material of the core, for example polytetrafluoroethylene. The element is also distinguished by the fact that the outer layer together with the sublayer is attached to the core through a nonhardening and nondrying glue composition, for example, based on rubber, rosin, lanolin, vaseline oil and zinc oxide.

  11. The chemical composition of nearby young associations: s-process element abundances in AB Doradus, Carina-Near, and Ursa Major

    CERN Document Server

    D'Orazi, Valentina; Desidera, Silvano; Covino, Elvira; Andrievsky, Sergei M; Gratton, Raffaele G

    2012-01-01

    Recently, several studies have shown that young, open clusters are characterised by a considerable over-abundance in their barium content. In particular, D'Orazi et al. (2009) reported that in some younger clusters [Ba/Fe] can reach values as high as ~0.6 dex. The work also identified the presence of an anti-correlation between [Ba/Fe] and cluster age. For clusters in the age range ~4.5 Gyr-500 Myr, this is best explained by assuming a higher contribution from low-mass asymptotic giant branch stars to the Galactic chemical enrichment. The purpose of this work is to investigate the ubiquity of the barium over-abundance in young stellar clusters. We analysed high-resolution spectroscopic data, focusing on the s-process elemental abundance for three nearby young associations, i.e. AB Doradus, Carina-Near, and Ursa Major. The clusters have been chosen such that their age spread would complement the D'Orazi et al. (2009) study. We find that while the s-process elements Y, Zr, La, and Ce exhibit solar ratios in all...

  12. Variants within the yeast Ty sequence family encode a class of structurally conserved proteins.

    OpenAIRE

    Fulton, A.M.; Mellor, J; Dobson, M J; J. Chester; Warmington, J R; Indge, K J; Oliver, S. G.; de la Paz, P; Wilson, W; Kingsman, A J

    1985-01-01

    The Ty transposable elements of Saccharomyces cerevisiae form a heterogeneous family within which two broad structural classes (I and II) exist. The two classes differ by two large substitutions and many restriction sites. We show that, like class I elements a class II element, Tyl-17, also appears to contain at least two major protein coding regions, designated TYA and TYB, and the organisational relationship of these regions has been conserved. The TYA genes of both classes encode proteins,...

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

    Science.gov (United States)

    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.

  14. Finite elements of nonlinear continua

    CERN Document Server

    Oden, J T

    2000-01-01

    Geared toward undergraduate and graduate students, this text extends applications of the finite element method from linear problems in elastic structures to a broad class of practical, nonlinear problems in continuum mechanics. It treats both theory and applications from a general and unifying point of view.The text reviews the thermomechanical principles of continuous media and the properties of the finite element method, and then brings them together to produce discrete physical models of nonlinear continua. The mathematical properties of these models are analyzed, along with the numerical s

  15. Algorithm BIDIMS for Automated Systematization of Data Array. Case Study: Rediscovering Mendeleev’s Periodic Table of Chemical Elements

    OpenAIRE

    Zagoruiko, Andrey; Zagoruiko, Nikolay

    2004-01-01

    The method (algorithm BIDIMS) of multivariate objects display to bidimensional structure in which the sum of differences of objects properties and their nearest neighbors is minimal is being described. The basic regularities on the set of objects at this ordering become evident. Besides, such structures (tables) have high inductive opportunities: many latent properties of objects may be predicted on their coordinates in this table. Opportunities of a method are illustrated on ...

  16. Computer modelling of the chemical speciation of lanthanide and actinide elements in the human gastrointestinal tract: mouth and stomach

    International Nuclear Information System (INIS)

    Jesse 53 computer modelling was used to produce biokinetic models of the gastrointestinal tract in order for the radiation dose from internally deposited radionuclides to be calculated. Preliminary estimations of the interactions of Eu and Am with all the metal binding species present in the mouth and stomach, i.e. saliva over a pH range of 5.6-7.6, and gastric juice over a pH range of 1.5-5.5, and at a temperature of 37 deg. C, have been made. The development of the models, and initial validation results for the use of Eu as a surrogate for Am, are presented and discussed. From these aqueous studies it appears that the use of Eu as a surrogate for Am in saliva or gastric juice is doubtful. However, further speciation modelling, incorporating solids, is in process to confirm these findings. (author)

  17. Hotspots for Vitamin-Steroid-Thyroid Hormone Response Elements Within Switch Regions of Immunoglobulin Heavy Chain Loci Predict a Direct Influence of Vitamins and Hormones on B Cell Class Switch Recombination.

    Science.gov (United States)

    Hurwitz, Julia L; Penkert, Rhiannon R; Xu, Beisi; Fan, Yiping; Partridge, Janet F; Maul, Robert W; Gearhart, Patricia J

    2016-03-01

    Vitamin A deficiencies are common throughout the world and have a significant negative influence on immune protection against viral infections. Mouse models demonstrate that the production of IgA, a first line of defense against viruses at mucosal sites, is inhibited in the context of vitamin A deficiency. In vitro, the addition of vitamin A to activated B cells can enhance IgA expression, but downregulate IgE. Previous reports have demonstrated that vitamin A modifies cytokine patterns, and in so doing may influence antibody isotype expression by an indirect mechanism. However, we have now discovered hundreds of potential response elements among Sμ, Sɛ, and Sα switch sites within immunoglobulin heavy chain loci. These hotspots appear in both mouse and human loci and include targets for vitamin receptors and related proteins (e.g., estrogen receptors) in the nuclear receptor superfamily. Full response elements with direct repeats are relatively infrequent or absent in Sγ regions although half-sites are present. Based on these results, we pose a hypothesis that nuclear receptors have a direct effect on the immunoglobulin heavy chain class switch recombination event. We propose that vitamin A may alter S site accessibility to activation-induced deaminase and nonhomologous end-joining machinery, thereby influencing the isotype switch, antibody production, and protection against viral infections at mucosal sites. PMID:26741514

  18. The effect of chemical transformations on terrestrial element cycling and food-chain transport of technetium-99

    International Nuclear Information System (INIS)

    The environmental behavior of technetium-99 (99Tc) is dominated by oxidation-reduction reactions and, for valence states, by complex formation with organics. Pertechnetate anion is the migratory form found in shallow groundwaters adjacent to radioactive waste disposal sites, but transformations in the terrestrial environment result in a behavior that is very different than that expected of a soluble anion. Technetium bioaccumulates in the transfer from soil to plant, but Tc incorporated in plants is less readily absorbed from the gastrointestinal tract of animals than pertechnetate. In soil, there is a dynamic equilibrium between pertechnetate, the form available for plant uptake, and reduced/complexed forms. Following uptake by forest trees, pertechnetate is incorporated in the structural components of leaf cell walls. An ecosystem model has been developed to explain the uptake, recycling, transformation, and controlling variables for the mobility of 99Tc in humid deciduous forests adjacent to radioactive waste disposal areas

  19. 化学元素周期表中以神话人物名称命名的化学元素英文名称分析%Analysis of the English Name of the Chemical Element in the Periodic Table of Chemical Elements Named after the Name of the Mythological Figure

    Institute of Scientific and Technical Information of China (English)

    王琦

    2012-01-01

    欧洲各国神话尤其是希腊罗马神话,对现代社会文明历史的影响是多方面的,在化学史上对化学元素的命名方面,其影响也不容小视,因此了解以神话人物名称对元素命名的方法,有助于加深对元素周期表的了解,有助于更好地理解欧洲各国古代神话对西方社会文化的影响。%European mythology, especially Greek and Roman mythology, the influence in history of modem society civili- zation is various, its influence can not be overlooked in the naming of the chemical history of the chemical elements, and therefore understand the name of the mythological figure named elements, help deepen the understanding of the periodic tab le, and contribute to a better understanding of the ancient myths of Western society and culture in European countries.

  20. Possibilities of chemical isolation of element 106 from aqueous solutions according to the model experiments with short lived tungsten isotopes

    International Nuclear Information System (INIS)

    A rapid method for continuous separation of short-lived tungsten isotopes from the lanthanides has been developed. It consists in transforming nuclear reaction products from the target by an aerosol jet to an absorber where the KCl particulates are dissolved in 0.2 M HF and percolating the product solution through three successively linked columns filled with ion exchange resins Dowex 50X8 (cationite), Dowex 1X8 (anionite) and again Dowex 50X8. 3 refs

  1. Effect of age and diameter class on the properties of wood from clonal Eucalyptus

    Directory of Open Access Journals (Sweden)

    Wilma Michele Santos Santana

    2012-03-01

    Full Text Available The objective of this work was to evaluate the influence of age and diameter class on the physical, thermal and chemical characteristics of a clone of Eucalyptus grandis and Eucalyptus urophylla. The material originated from a reforestation site owned by GERDAU S.A. and included trees at age 34, 48, 61, 74 and 86 months. Two trees were selected per age in each diameter class, observing the proportion of each established plot. Analyses of physical characteristics included wood basic density, dry matter weight and carbon stock, and of chemical characteristics included holocellulose, total extractives content, total lignin and ash content, in addition to elemental and thermal analysis of the wood. Results led to the conclusion that most wood properties were influenced by age and diameter class. The species was found to have great potential for production of biomass and generation of heat energy, potentially convertible into mechanical energy and electricity.

  2. On a class of topological groups

    Directory of Open Access Journals (Sweden)

    Dinamérico P. Pombo Jr

    2006-11-01

    Full Text Available A topological group is an SNS-group if its identity element possessesa fundamental system of neighborhoods formed by normal subgroups. In this paper we prove the existence of initial SNS-topologies, from which we derive that the class of SNS-groups is closed under the formation of products and projective limits, and we prove the existence of final SNS-topologies, from which we derive that the class of SNS-groups is closed under the formation of free products and inductive limits.

  3. XIII International science and technology conference High-tech chemical technologies-2010 with elements of Scientific school for young people Innovations in chemistry: achievements and prospects. Summaries of reports

    International Nuclear Information System (INIS)

    Materials of the XIII International science and technology conference High-tech chemical technologies-2010 with elements of Scientific school for young people Innovations in chemistry: achievements and prospects (29 June-2 July 2010, Ivanovo) are presented. During the conference the following areas: theoretical aspects of chemical technology; technology of deep oil refining and the production of organic substances; technology of drugs and biologically active substances; technology of inorganic materials, polymers and composites based on them - the technological principles and methods of synthesis, modification, and processing; environmental and economic problems of chemical technologies and their solutions are considered

  4. Aerosol chemical elemental mass concentration at lower free troposphere

    Science.gov (United States)

    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.

  5. Hydrogeochemistry in soils and sediments in the area of the Lagoa Campestre lake (Salitre, MG, Brazil) : chemical balances of major and trace elements and dynamics of rare earth elements

    OpenAIRE

    Sondag, Francis; Soubiès, François; Fortune, J.P.; B. Dupré; Magat, P.; Melfi, A. (collab.)

    1997-01-01

    Study of the sediments filling the Lagoa Campestre peaty lake (Minas Gerais, Brazil) showed a high rare earth elements (REE) content, especially in phosphatic bottom beds (authigenic phosphates), whose fluctuations could be related to variations in the erosion conditions and the nature of the plant cover. In order to understand better the mode of complexation and transport of trace elements in this environment, a geochemical survey was undertaken of the waters of the area, both in surface str...

  6. Elemental composition of charcoal sorbants

    International Nuclear Information System (INIS)

    Despite the widespread use of charcoal sorbants in the collection of vapor phase chemicals and trace atmospheric gases, the charcoal's initial elemental composition is frequently not well characterized. This information is important in predicting possible reactions of collected chemicals within the charcoal matrix, the production of artifacts, and the possible sample loss during sampling. Also, it is critical in choosing the proper analytical technique for chemical measurement. For example, the authors have recently found that instrumental neutron activation analysis cannot be applied to measure mercury concentrations in oil bottom ashes, which are similar to some charcoals, due to the analytical interference of high levels of rare earth elements in these matrices. It is therefore vital to have at least a general knowledge of the major constituents of the sampling media for proper sampling and the selection of suitable analytical techniques

  7. Minor modifications of the C-terminal helix reschedule the favored chemical reactions catalyzed by theta class glutathione transferase T1-1.

    Science.gov (United States)

    Shokeer, Abeer; Mannervik, Bengt

    2010-02-19

    Adaptive responses to novel toxic challenges provide selective advantages to organisms in evolution. Glutathione transferases (GSTs) play a pivotal role in the cellular defense because they are main contributors to the inactivation of genotoxic compounds of exogenous as well as of endogenous origins. GSTs are promiscuous enzymes catalyzing a variety of chemical reactions with numerous alternative substrates. Despite broad substrate acceptance, individual GSTs display pronounced selectivities such that only a limited number of substrates are transformed with high catalytic efficiency. The present study shows that minor structural changes in the C-terminal helix of mouse GST T1-1 induce major changes in the substrate-activity profile of the enzyme to favor novel chemical reactions and to suppress other reactions catalyzed by the parental enzyme. PMID:20022951

  8. Designing a new class of distributed systems

    CERN Document Server

    Mikkilineni, Rao

    2011-01-01

    Designing a New Class of Distributed Systems closely examines the Distributed Intelligent Managed Element (DIME) Computing Model, a new model for distributed systems, and provides a guide to implementing Distributed Managed Workflows with High Reliability, Availability, Performance and Security. The book also explores the viability of self-optimizing, self-monitoring autonomous DIME-based computing systems. Designing a New Class of Distributed Systems is designed for practitioners as a reference guide for innovative distributed systems design. Researchers working in a related field will also f

  9. Minor Modifications of the C-terminal Helix Reschedule the Favored Chemical Reactions Catalyzed by Theta Class Glutathione Transferase T1-1*

    OpenAIRE

    Shokeer, Abeer; Mannervik, Bengt

    2009-01-01

    Adaptive responses to novel toxic challenges provide selective advantages to organisms in evolution. Glutathione transferases (GSTs) play a pivotal role in the cellular defense because they are main contributors to the inactivation of genotoxic compounds of exogenous as well as of endogenous origins. GSTs are promiscuous enzymes catalyzing a variety of chemical reactions with numerous alternative substrates. Despite broad substrate acceptance, individual GSTs display pronounced selectivities ...

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

    Science.gov (United States)

    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).

  11. A New Geochemical Classification of Elements

    Institute of Scientific and Technical Information of China (English)

    Qi Changmou; L. Lynn Chyi

    2001-01-01

    The geochemical classification proposed by Goldschmidt was based on meteoritic analysis and elemental partition in blast furnace. There are many surprises when applied to the discussion of natural occurrences. A modified classification of elements based on basic chemical properties and their occurrences. A modified classification of elements based on basic chemical properties and their occurrences in nature is, therefore, proposed for students learning geochemistry and geologists working in the field. Elements are classified into six groups including lithophile, oxyphile, siderophile, chalcophile, biophile, and atmophile elements. Five terms are taken from Goldshcmidt's original classification. Oxyphile is a new term.

  12. Mathematical Modeling of Chemical Stoichiometry

    Science.gov (United States)

    Croteau, Joshua; Fox, William P.; Varazo, Kristofoland

    2007-01-01

    In beginning chemistry classes, students are taught a variety of techniques for balancing chemical equations. The most common method is inspection. This paper addresses using a system of linear mathematical equations to solve for the stoichiometric coefficients. Many linear algebra books carry the standard balancing of chemical equations as an…

  13. The Paradox of Paperless Classes.

    Science.gov (United States)

    Lackie, Paula

    1998-01-01

    Describes paperless classes developed at Carleton College that augment traditional classes by giving students and faculty the ability to share digital course-related materials via the campus computer network. Presents a case study of a managerial economics course, and includes problems with various aspects of the course and solutions. (LRW)

  14. A Touch of...Class!

    Science.gov (United States)

    Netten, Joan W., Ed.

    1984-01-01

    A collection of ideas for class activities in elementary and secondary language classes includes a vocabulary review exercise and games of memory, counting, vocabulary, flashcard tic-tac-toe, dice, trashcans, questioning, and spelling. Some are designed specifically for French. (MSE)

  15. The Generalizability of Class Means

    Science.gov (United States)

    Kane, Michael T.; Brennan, Robert L.

    1977-01-01

    Dependability of class means is analyzed by applying generalizability to a split-plot design with students nested within classes. Basic generalizability concepts are reviewed, and the derivation and interpretation of distinct generalizability concepts are discussed. Four generalizability coefficients are compared with each other and with the three…

  16. Novelty Detection in MultiClass Scenarios with Incomplete Set of Class Labels

    OpenAIRE

    Vinokurov, Nomi; Weinshall, Daphna

    2016-01-01

    We address the problem of novelty detection in multiclass scenarios where some class labels are missing from the training set. Our method is based on the initial assignment of confidence values, which measure the affinity between a new test point and each known class. We first compare the values of the two top elements in this vector of confidence values. In the heart of our method lies the training of an ensemble of classifiers, each trained to discriminate known from novel classes based on ...

  17. Chemical Compatibility of Polymeric Materials.

    Science.gov (United States)

    Solen, Kenneth A.; Kuchar, Marvin C.

    1990-01-01

    Presents some principles for specifying general classes of polymers for predicting relative chemical attack from acids, bases, oxidants, and certain common antagonists. Also discusses predicting relative solvent effects. Suggests uses of this information in two or three lectures in a chemical engineering materials course. (YP)

  18. First investigations of the influence of IVB elements (Ti, Zr, and Hf) on the chemical durability of soda-lime borosilicate glasses

    International Nuclear Information System (INIS)

    The influence of IVB elements (Zr, Ti, and Hf) on the glass structure and on the alteration kinetics of soda-lime borosilicate glasses has been studied at various stages of glass leaching corresponding to the initial dissolution rate, rate drop, and residual rate regimes. The effect of these elements on the limiting mechanisms of the glass durability as well as the chemistry of both solution and alteration layer are inter-related, depending on the reaction progress. The effect of IVB elements on the glass structure was investigated using 11B MAS NMR. The IVB elements are compensated primarily by Na rather than Ca, at the expense of tetra-coordinated boron. The addition of HfO2 or ZrO2 decreases the initial dissolution rate in a similar way. Moreover, adding ZrO2 limits the rate drop in saturated media. The initial dissolution rate decrease is less significant when Ti is added, and a quick drop of the dissolution rate is observed up to 4 mol% TiO2. At low IVB element concentration, glasses containing Ti and Zr show different residual rates arising from the precipitation of magadiite (Na2Si14O29 center dot 11H2O), at the surface of Ti-bearing glasses. The influence of IVB elements on glass alteration indicates that, unlike Ti, Zr and Hf plays a similar role in the structure of borosilicate glasses. (authors)

  19. Vertical exchange and chemical conversion of trace elements over topographically complex terrain; Vertikaler Austausch und chemische Umwandlung von Spurenstoffen ueber topographisch gegliedertem Gelaende

    Energy Technology Data Exchange (ETDEWEB)

    Kuntze, K.

    2001-10-01

    The influence of topography on the vertical exchange of trace elements was investigated with the aid of a numeric simulation model. It is a couopled 3D model consisting of the mesoscale model KAMM and the dispersion model DRAIS, extended by the gaseous phase mechanism of the RADM model. This way, both meteorological and chemical processes can be analyzed in a preselected time and spatial resolution. The simulations were validated by a comparison with measurements made during the TRACT campaign. Satisfactory agreement between the two was established. [German] In der vorliegenden Arbeit wurde der Einfluss der Topographie auf den vertikalen Austausch von Spurenstoffen mit Hilfe eines numerischen Simulationsmodells untersucht. Bei dem Simulationsmodell handelt es sich um ein dreidimensionales gekoppeltes Modell, welches aus dem mesoskaligen Modell KAMM und dem um den Gasphasenmechanismus des RADM-Modells erweiterten Ausbreitungsmodell DRAIS besteht. Mit diesem Modellsystem war es moeglich, sowohl meterologische als auch chemische Prozesse in einer vorher gewaehlten zeitlichen und raeumlichen Aufloesung zu betrachten. Um die Qualitaet der Simulation und damit deren Verwendbarkeit fuer die Untersuchungen festzustellen, wurde ein Vergleich mit Messungen durchgefuehrt. Dazu wurden berechnete meterologische und chemische Groessen mit den waehrend der Feldmesskampagne TRACT gemessenen Groessen verglichen. Der Vergleich der simulierten Groessen sowohl mit Radiosondenaufstiegen als auch mit Zeitreihen und Flugzeugmessungen lieferte eine gute Uebereinstimmung. (orig.)

  20. Rapid Neutron Capture Process in Supernovae and Chemical Element Formation

    Indian Academy of Sciences (India)

    Rulee Baruah; Kalpana Duorah; H. L. Duorah

    2009-09-01

    The rapid neutron capture process (r-process) is one of the major nucleosynthesis processes responsible for the synthesis of heavy nuclei beyond iron. Isotopes beyond Fe are most exclusively formed in neutron capture processes and more heavier ones are produced by the r-process. Approximately half of the heavy elements with mass number ≻ 70 and all of the actinides in the solar system are believed to have been produced in the r-process. We have studied the r-process in supernovae for the production of heavy elements beyond = 40 with the newest mass values available. The supernova envelopes at a temperature ≻ 109 K and neutron density of 1024 cm-3 are considered to be one of the most potential sites for the r-process. The primary goal of the r-process calculations is to fit the global abundance curve for solar system r-process isotopes by varying time dependent parameters such as temperature and neutron density. This method aims at comparing the calculated abundances of the stable isotopes with observation.We have studied the r-process path corresponding to temperatures ranging from 1.0 × 109 K to 3.0 × 109 K and neutron density ranging from 1020 cm-3 to 1030 cm-3. With temperature and density conditions of 3.0 × 109 K and 1020 cm-3 a nucleus of mass 273 was theoretically found corresponding to atomic number 115. The elements obtained along the r-process path are compared with the observed data at all the above temperature and density range.

  1. Advanced Manufacturing Technologies (AMT): Low Cost Upper Stage-Class Propulsion Development Element

    Data.gov (United States)

    National Aeronautics and Space Administration — As manufacturing technologies have matured, it now appears possible to build all the major components and subsystems of an upper stage-class rocket engine for...

  2. The Complexity of Identifying Large Equivalence Classes

    DEFF Research Database (Denmark)

    Skyum, Sven; Frandsen, Gudmund Skovbjerg; Miltersen, Peter Bro;

    1999-01-01

    We prove that at least 3k−4/k(2k−3)(n/2) – O(k)equivalence tests and no more than 2/k (n/2) + O(n) equivalence tests are needed in the worst case to identify the equivalence classes with at least k members in set of n elements. The upper bound is an improvement by a factor 2 compared to known res...

  3. Distribution of chemical elements in soils and stream sediments in the area of abandoned Sb-As-Tl Allchar mine, Republic of Macedonia.

    Science.gov (United States)

    Bačeva, Katerina; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu; Makreski, Petre

    2014-08-01

    The aim of this study was to investigate the distribution of some toxic elements in topsoil and subsoil, focusing on the identification of natural and anthropogenic element sources in the small region of rare As-Sb-Tl mineralization outcrop and abandoned mine Allchar known for the highest natural concentration of Tl in soil worldwide. The samples of soil and sediments after total digestion were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Factor analysis (FA) was used to identify and characterize element associations. Six associations of elements were determined by the method of multivariate statistics: Rb-Ta-K-Nb-Ga-Sn-Ba-Bi-Li-Be-(La-Eu)-Hf-Zr-Zn-In-Pd-Ag-Pt-Mg; Tl-As-Sb-Hg; Te-S-Ag-Pt-Al-Sc-(Gd-Lu)-Y; Fe-Cu-V-Ge-Co-In; Pd-Zr-Hf-W-Be and Ni-Mn-Co-Cr-Mg. The purpose of the assessment was to determine the nature and extent of potential contamination as well as to broadly assess possible impacts to human health and the environment. The results from the analysis of the collected samples in the vicinity of the mine revealed that As and Tl elements have the highest median values. Higher median values for Sb are obviously as a result of the past mining activities and as a result of area surface phenomena in the past. PMID:24906071

  4. Element geochemistry of weathering profile of dolomitite and its implications for the average chemical composition of the upper-continental crust--Case studies from the Xinpu profile,northern Guizhou Province,China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Geochemical behavior of chemical elements is studied in a dolomitite weathering profile in upland of karst terrain in northern Guizhou.Two stages can be recognized during the process of in situ weathering of dolomitite:the stage of sedentary accumulation of leaching residue of dolomitite and the stage of chemical weathering evolution of sedentary soil.Ni,Cr,Mo,W and Ti are the least mobile elements with reference to Al.The geochemical behavior of REE is similar to that observed in weathering of other types of rocks.Fractionation of REE is noticed during weathering,and the two layers of REE enrichments are thought to result from downward movement of the weathering front in response to changes in the environment.It is considered that the chemistry of the upper part of the profile,which was more intensively weathered,is representative of the mobile components of the upper curst at the time the dolomitite was formed,while the less weathered lower profile is chemically representative of the immobile constitution.Like glacial till and loess,the "insoluble" materials in carbonate rocks originating from chemical sedimentation may also provide valuable information about the average chemical composition of the upper continental crust.

  5. A study on monitoring methodology for trace elements in the environment through chemical analysis of hair. Part of a coordinated programme on nuclear methods in health-related monitoring of trace element pollutants

    International Nuclear Information System (INIS)

    An attempt was made to monitor community exposure to environmental As, Cd, Cr, Hg, Mn, Pb and Se using hair analysis by instrumental neutron activation analysis and atomic absorption spectroscopy. Hair samples were collected from male and female subjects from six Japanese localities. Samples from each locality were respectively mixed and analysed for elements of interest. The results indicated that this approach was effective in revealing geographical differences of hair elemental levels. The method is suitable for a routine monitoring programme of community exposure to environmental metal pollutants

  6. Distribution of chemical elements in soils and stream sediments in the area of abandoned Sb–As–Tl Allchar mine, Republic of Macedonia

    Energy Technology Data Exchange (ETDEWEB)

    Bačeva, Katerina [Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, POB 162, 1000 Skopje (Macedonia, The Former Yugoslav Republic of); Stafilov, Trajče, E-mail: trajcest@pmf.ukim.mk [Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, POB 162, 1000 Skopje (Macedonia, The Former Yugoslav Republic of); Šajn, Robert [Geological Survey of Slovenia, Ljubljana (Slovenia); Tănăselia, Claudiu [INCDO-INOE 2000 Research Institute for Analytical Instrumentation (ICIA), Cluj-Napoca (Romania); Makreski, Petre [Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, POB 162, 1000 Skopje (Macedonia, The Former Yugoslav Republic of)

    2014-08-15

    The aim of this study was to investigate the distribution of some toxic elements in topsoil and subsoil, focusing on the identification of natural and anthropogenic element sources in the small region of rare As–Sb–Tl mineralization outcrop and abandoned mine Allchar known for the highest natural concentration of Tl in soil worldwide. The samples of soil and sediments after total digestion were analyzed by inductively coupled plasma–mass spectrometry (ICP–MS) and inductively coupled plasma–atomic emission spectrometry (ICP–AES). Factor analysis (FA) was used to identify and characterize element associations. Six associations of elements were determined by the method of multivariate statistics: Rb–Ta–K–Nb–Ga–Sn–Ba–Bi–Li–Be–(La–Eu)–Hf–Zr–Zn–In–Pd–Ag–Pt–Mg; Tl–As–Sb–Hg; Te–S–Ag–Pt–Al–Sc–(Gd–Lu)–Y; Fe–Cu–V–Ge–Co–In; Pd–Zr–Hf–W–Be and Ni–Mn–Co–Cr–Mg. The purpose of the assessment was to determine the nature and extent of potential contamination as well as to broadly assess possible impacts to human health and the environment. The results from the analysis of the collected samples in the vicinity of the mine revealed that As and Tl elements have the highest median values. Higher median values for Sb are obviously as a result of the past mining activities and as a result of area surface phenomena in the past. - Highlights: • Soil and river sediments were analyzed from Sb–As–Tl Allchar locality. • An increased content of certain toxic elements for environment was determined. • Highest As and Tl contents are obtained in the close vicinity of Allchar mine. • River sediments portray 160 times higher content of Sb than EU values. • The results classify Allchar as probably the highest natural Tl-deposit worldwide.

  7. Distribution of chemical elements in soils and stream sediments in the area of abandoned Sb–As–Tl Allchar mine, Republic of Macedonia

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the distribution of some toxic elements in topsoil and subsoil, focusing on the identification of natural and anthropogenic element sources in the small region of rare As–Sb–Tl mineralization outcrop and abandoned mine Allchar known for the highest natural concentration of Tl in soil worldwide. The samples of soil and sediments after total digestion were analyzed by inductively coupled plasma–mass spectrometry (ICP–MS) and inductively coupled plasma–atomic emission spectrometry (ICP–AES). Factor analysis (FA) was used to identify and characterize element associations. Six associations of elements were determined by the method of multivariate statistics: Rb–Ta–K–Nb–Ga–Sn–Ba–Bi–Li–Be–(La–Eu)–Hf–Zr–Zn–In–Pd–Ag–Pt–Mg; Tl–As–Sb–Hg; Te–S–Ag–Pt–Al–Sc–(Gd–Lu)–Y; Fe–Cu–V–Ge–Co–In; Pd–Zr–Hf–W–Be and Ni–Mn–Co–Cr–Mg. The purpose of the assessment was to determine the nature and extent of potential contamination as well as to broadly assess possible impacts to human health and the environment. The results from the analysis of the collected samples in the vicinity of the mine revealed that As and Tl elements have the highest median values. Higher median values for Sb are obviously as a result of the past mining activities and as a result of area surface phenomena in the past. - Highlights: • Soil and river sediments were analyzed from Sb–As–Tl Allchar locality. • An increased content of certain toxic elements for environment was determined. • Highest As and Tl contents are obtained in the close vicinity of Allchar mine. • River sediments portray 160 times higher content of Sb than EU values. • The results classify Allchar as probably the highest natural Tl-deposit worldwide

  8. Phases of Environmental Evolution Indicated by Primary Chemical Elements and Paleontological Records in the Upper Pleistocene-Holocene Series for the Salawusu River Valley, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the Milanggouwan section in China's Salawusu River valley into six segments: MGS1, MGS2, MGS3,MGS4, MGS5 and MGS6. The boundary ages for MGS1 (the Dishaogouwan and Dagouwan Formations), MGS2 (the upper Chengchuan Formation), MGS3 (the middle Chengchuan Formation),MGS4 (the lower Chengchuan Formation), MGS5 (most strata of the Salawusu Formation) and MGS6 (the bottom of the Salawusu Formation and the top of the Lishi Formation) correspond to those of MIS1, MIS2, MIS3, MIS4, MIS5 and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments (MGS5a, MGS5b, MGS5c,MGS5d and MGS5e) and the boundary ages of these subsegments correspond to those of MIS5a,MIS5b, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers,and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate (and particularly in the East Asian monsoon) during the glacial and interglacial periods.

  9. Green Chemical Synthesis of II-VI Semiconductor Quantum Dots

    OpenAIRE

    Shahid, Robina

    2012-01-01

    Nanotechnology is the science and technology of manipulating materials at atomic and molecular scale with properties different from bulk. Semiconductor QDs are important class of nanomaterials with unique physical and chemical properties owing to the quantum confinement effect. Size dependent optical properties make research on semiconductor QDs more attractive in the field of nanotechnology. Semiconductor QDs are usually composed of combination of elements from groups II–VI, III–V, or IV–VI ...

  10. Chemical analysis of solid materials by a LIMS instrument designed for space research: 2D elemental imaging, sub-nm depth profiling and molecular surface analysis

    Science.gov (United States)

    Moreno-García, Pavel; Grimaudo, Valentine; Riedo, Andreas; Neuland, Maike B.; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2016-04-01

    Direct quantitative chemical analysis with high lateral and vertical resolution of solid materials is of prime importance for the development of a wide variety of research fields, including e.g., astrobiology, archeology, mineralogy, electronics, among many others. Nowadays, studies carried out by complementary state-of-the-art analytical techniques such as Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS), Glow Discharge Time-of-Flight Mass Spectrometry (GD-TOF-MS) or Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) provide extensive insight into the chemical composition and allow for a deep understanding of processes that might have fashioned the outmost layers of an analyte due to its interaction with the surrounding environment. Nonetheless, these investigations typically employ equipment that is not suitable for implementation on spacecraft, where requirements concerning weight, size and power consumption are very strict. In recent years Laser Ablation/Ionization Mass Spectrometry (LIMS) has re-emerged as a powerful analytical technique suitable not only for laboratory but also for space applications.[1-3] Its improved performance and measurement capabilities result from the use of cutting edge ultra-short femtosecond laser sources, improved vacuum technology and fast electronics. Because of its ultimate compactness, simplicity and robustness it has already proven to be a very suitable analytical tool for elemental and isotope investigations in space research.[4] In this contribution we demonstrate extended capabilities of our LMS instrument by means of three case studies: i) 2D chemical imaging performed on an Allende meteorite sample,[5] ii) depth profiling with unprecedented sub-nm vertical resolution on Cu electrodeposited interconnects[6,7] and iii) preliminary molecular desorption of polymers without assistance of matrix or functionalized substrates.[8] On the whole

  11. Class in Metropolitan India: The Rise of the Middle Classes

    OpenAIRE

    Mooij, Jos; Lama-Rewal, S.T.

    2009-01-01

    textabstractIt is almost a cliché to say that India’s appearance and image (internationally as well as self-image) have changed dramatically in the last fifteen years. Instead of being associated with rural poverty, India is now associated with high rates of economic growth, a booming Information Technology (IT) sector and, particularly, an increasingly expanding middle class that consumes and behaves like elites and middle classes elsewhere in the world. Considering that cities concentrate m...

  12. The chemical speciation and analysis of trace elements in sediment with Neutron Activation Analytical method(NAA) and atomic mass spectrometry

    International Nuclear Information System (INIS)

    In this research, first of all, the analytical methods for the determination of major elements in sediment have been developed with ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The analytical results of major elements (Al, Ca, K, Fe, Mg) with Cool ICP-MS were much better than those with normal ICP-MS. The analytical results were compared with those of NAA (Neutron Activation Analysis). NAA were a little superior to ICP-MS for the determination of major elements in sediment as a non-destructive trace analytical trace analytical method. The analytical methods for the determination of minor elements (Cr, Ce, U, Co, Pb, As, Se) have been also developed with ICP-MS. The analytical results by standard calibration curve with ICP-MS were not accurate due to the matrix interferences. Thus, the internal standard method was applied, then the analytical results for minor elements with ICP-MS were greatly improved. The analytical results obtained by ICP-MS were compared with those obtained by NAA. It showed that the two analytical methods have great capabilities for the determination of minor elements in sediments. Accordingly, the NAA will plan an important role in analysis of environment sample with complex matrix. ICP-MS also will play an important role because it has a great capability for the determination of Pb that could not be determined by NAA

  13. Elements of life

    OpenAIRE

    Samuel, J.

    2004-01-01

    A Biography of J.M.W. Turner's life told through the use of the elements. A five screen video installation. This is the Main Screen which was complimented by four video screens to represent each element.Shown at the Community Pharmacy Gallery May 2004.

  14. The Elements of Empathy.

    Science.gov (United States)

    Iannotti, Ronald J.

    When assessing the influence of empathy on prosocial motivation, analyzing empathy alone would lead to a misunderstanding. We must also assess other elements of the situation, such as the altruist's coping skills and situational constraints. In a similar manner empathy itself should be conceptualized as a process with many elements. One way to…

  15. 学习型班级视域下高校辅导员胜任力要素分析%Elements Analysis to the Competency of University Counselors in Perspective of Learning-Oriented Class

    Institute of Scientific and Technical Information of China (English)

    肖柯; 石清云

    2013-01-01

    As the construction of a learning-oriented class puts forward new requirements for the professional competency of university counselors under the new situation, the author makes an analysis in this paper to the competency of counselors from five aspects, self-transcendence, mental model improvement, shared vision building, team learning and systematic thinking, to form a competency elements model covering three levels, foundation, core and key as well as nine categories, and then establishes and perfects an competency improvement system for counselors with the integration of selection, training, management and evaluation on the basis of the above model, by standardizing the selection and allocation mechanism, innovating the management and coordination mechanism, perfecting the training and learning mechanism, and optimizing the incentive and evaluation mechanism, so as to promote the competence level of counselors and build a learning-oriented class.%  新形势下构建高校学习型班级对辅导员职业胜任力提出了新的要求,从自我超越、改善心智模式、建立共同愿景、团队学习、系统思考五项修炼的角度对辅导员胜任力进行分析,可以形成涵盖基础、核心、关键3个层次的胜任力要素模型,并以此为基础通过规范选拔配备机制、创新管理协调机制、完善培训学习机制、优化激励考核机制,建立健全融选拔、培训、管理、考核于一体的辅导员胜任力提升体系,达到提升辅导员胜任力水平、构建学习型班级的目的。

  16. Pesticides, selected elements, and other chemicals in adult total diet samples October 1979-September 1980

    International Nuclear Information System (INIS)

    The US Food and Drug Administration (FDA) conducts Total Diet Studies to determine the dietary intake of selected pesticides, industrial chemicals, and elements (including radionuclides). These studies involve the retail purchase and analysis of foods representative of the diets of infants, toddlers, and adults. The individual food items are separated into a number of food groups, each of which is analyzed as a composite. This report summarizes the results for adult Total Diet samples collected in 20 cities between October 1979 and September 1980. The average concentration, range of concentrations, and calculated average daily intake of each chemical found are presented by food group. The average daily intakes of the chemicals are similar to those found in the several preceding years and are within acceptable limits. The results for samples collected during the same period that represent the diets of infants and toddlers are reported separately

  17. Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation - Part 1: Major and minor element variation

    Science.gov (United States)

    Brügmann, G.; Krause, J.; Brachert, T. C.; Kullmer, O.; Schrenk, F.; Ssemmanda, I.; Mertz, D. F.

    2012-01-01

    Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project provides a comprehensive data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from Hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lacustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system. Secondary alteration effects - in particular FeO, MnO, SO3 and F concentrations - are 2 to 10 times higher in fossil than in modern enamel; the secondary enrichment of these components in fossil dentin and cement is even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ∼1%). Linear regression analysis reveals tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40% to 300%) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite trend. Fossil enamel from Hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2

  18. Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation: 1. major and minor element variation

    Directory of Open Access Journals (Sweden)

    G. Brügmann

    2011-05-01

    the outer enamel rim.

    The linkage between lake and river water composition, bioavailability of elements for plants, animal nutrition and tooth formation is complex and multifaceted. The quality and limits of the MgO/Na2O and other proxies have to be established with systematic investigations relating chemical distribution patterns to sedimentary environment and to growth structures developing as secretion and maturation proceed during tooth formation.

  19. Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation: 1. major and minor element variation

    Science.gov (United States)

    Brügmann, G.; Krause, J.; Brachert, T. C.; Kullmer, O.; Schrenk, F.; Ssemmanda, I.; Mertz, D. F.

    2011-05-01

    Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project intends to provide a detailed data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe, to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lakustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system. Secondary alteration effects in particular FeO, MnO, SO3 and F concentrations, which are 2 to 10 times higher in fossil than in modern enamel; secondary enrichments in fossil dentin and cement are even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ~1 %). Linear regression analysis reveals very tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40 % to 300 %) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite variation. Fossil enamel from hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2O

  20. Сomposition and ratio of the chemical elements on the surfaces different by height of reindeer lichen podetia Cladonia rangiferina

    Directory of Open Access Journals (Sweden)

    Byazrov Lev

    2016-06-01

    Full Text Available In the paper the composition of 21 elements – Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ba, Pb – was compared in the upper, central, and lower parts of podetia surfaces of the reindeer lichen Cladonia rangiferina, sampled on the slope of Barguzinsky chain. For the measurement of the elements content (%, a sample-nondestructive μ-XRF spectrometer was used. It was stated that the share (% of the most elements, except for Cu and Zn, was highly variable. The content of the elements on the surfaces differs significantly between the studied parts of C. rangiferina podetia: mean values of the content of P, S, Cl, and K were statistically higher on the surface of the upper part of podetia, while those of Al, Si, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Co, and the total content – on the surface of the lower part of podetia. On all the parts of podetia very high value of the enrichment factor for As and Pb was established, and It was increased for P, Co, Ni, Cu, Zn.

  1. Chemical composition of Earth-like planets

    OpenAIRE

    Ronco, M. P.; Thiabaud, A.; Marboeuf, U.; Alibert, Y.; de Elía, G. C.; O. M. Guilera

    2015-01-01

    Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous ...

  2. Solar System Abundances of the Elements

    CERN Document Server

    Lodders, Katharina

    2010-01-01

    Representative abundances of the chemical elements for use as a solar abundance standard in astronomical and planetary studies are summarized. Updated abundance tables for solar system abundances based on meteorites and photospheric measurements are presented.

  3. Hydrologic characterization of the Fry Canyon, Utah site prior to field demonstration of reactive chemical barriers to control radionuclide and trace-element contamination in ground water

    Energy Technology Data Exchange (ETDEWEB)

    Naftz, D.L.; Freethey, G.W. [Geological Survey, Salt Lake City, UT (United States); Davis, J.A. [Geological Survey, Menlo Park, CA (United States)] [and others

    1997-12-31

    The Fry Canyon Site in southeastern Utah has been selected as a long term demonstration site to assess the performance of selected reaction barrier technologies for the removal of uranium and other trace elements from ground water. Objectives include site characterization and evaluation of barrier technologies.

  4. N=1 theories of class S_k

    OpenAIRE

    Gaiotto, Davide; Razamat, Shlomo S.

    2015-01-01

    We construct classes of ${\\cal N}=1$ superconformal theories elements of which are labeled by punctured Riemann surfaces. Degenerations of the surfaces correspond, in some cases, to weak coupling limits. Different classes are labeled by two integers (N,k). The k=1 case coincides with A_{N-1} ${\\cal N}=2$ theories of class S and simple examples of theories with k>1 are Z_k orbifolds of some of the A_{N-1} class S theories. For the space of ${\\cal N}=1$ theories to be complete in an appropriate...

  5. A library of function classes

    International Nuclear Information System (INIS)

    We have written a library of function classes in C++, which is distributed as part of the CLHEP foundation class libraries for High Energy Physics. The main goals of the library are to provide objects having all the mathematical behavior of functions, and to provide a mechanism for parameterizing these functions. Our functions support all the normal function operations such as addition, subtraction, multiplication, division, composition, et. cetera. The library allows programmers to compose complicated one-or multi-dimensional functions with great economy and natural semantics

  6. Influence of chemical and mineralogical properties of organic amendments on the selection of an adequate analytical procedure for trace elements determination.

    Science.gov (United States)

    García-Delgado, C; Cala, V; Eymar, E

    2012-01-15

    Six digestion procedures were tested to improve extraction methods for determination of trace elements in various organic amendments with high inorganic fractions. These procedures were tested in terms of pH, CaCO(3), organic matter, elemental analysis, BCR sequential extraction and X-ray diffraction analysis. Aqua regia extraction (ISO 11466), total digestion HF-HNO(3)-HClO(4) and four microwave-assisted digestions (i.e., HNO(3), HCl-HNO(3), HNO(3)-HF and HCl-HNO(3)-HF) were used. The effect of acid mixtures on microwave-assisted digestion of mineral fractions was assessed by Si and Al analysis and X-ray diffraction in the solid residues obtained. Microwave HF acid mixtures obtained highest trace element recoveries for all tested metals except Al. CaF(2) and CaAlF(5) precipitates were also detected using X-ray diffraction in the residues after microwave digestions with HF acid mixtures of amendments with high calcium content. A decision flowchart was suggested to determine the best acid mixture according to the amendment and the metals to be analyzed. PMID:22265513

  7. Investigation on the status of rare earth elements contained in the powder of spent fluorescent lamps

    International Nuclear Information System (INIS)

    Highlights: • Most of rare earth elements are contained in particles of size finer than 7 μm. • Most of Si, K and Na are contained in the coarser size-fractions. • The phases in the size-fractions of the fluorescent powder have been determined. • Europium is contained in yttrium oxide and in vanadium–yttrium oxides. • The crystallo–chemical composition of all the phases has been determined. - Abstract: The aim of this study is to examine the status of rare earth elements (REE) contained in the chemical compounds that make up the powder of spent fluorescent lamps, with a view of their recovery. The status of REE in the as-received powder, as well as in a few size-class fractions of it, has been established. This way, only those size-class fractions containing high REE concentrations can be considered in a recovery process. The investigation has been carried out using particle-size, chemical, TGA/DTA, XRPD, SEM-EDS and EMPA analyses. The last technique enabled to establish the status of REE within the lattice of the chemical compounds present in the powder. The fineness of the as-received powder and the higher REE concentration in the finest size-classes suggest that physical methods of separation should not be used to separate the REE-containing chemical compounds from each other. Leaching methods seem more suitable with a material of such size

  8. On uniqueness of characteristic classes

    DEFF Research Database (Denmark)

    Feliu, Elisenda

    2011-01-01

    We give an axiomatic characterization of maps from algebraic K-theory. The results apply to a large class of maps from algebraic K-theory to any suitable cohomology theory or to algebraic K-theory. In particular, we obtain comparison theorems for the Chern character and Chern classes and for the...... Adams operations and ¿-operations on higher algebraic K-theory. We show that the Adams operations and ¿-operations defined by Grayson agree with the ones defined by Gillet and Soulé....

  9. 鳄嘴花叶氨基酸和微量元素分析及其化学成分研究%Analysis of Amino Acids, Trace Elements and Chemical Constituents from the Leaves of Clinacanthus nutans

    Institute of Scientific and Technical Information of China (English)

    易博; 徐文彤; 邓盾; 邓涛

    2012-01-01

    目的 分析鳄嘴花叶中的氨基酸、微量元素及主要化学成分.方法 采用HPLC法和等离子体发射光谱法测定了鳄嘴花叶中氨基酸和微量元素的成分和含量,采用柱色谱法对鳄嘴花叶中的主要化学成分进行研究.结果 从鳄嘴花叶中分析测定出了17种氨基酸和11种微量元素,叶中总氨基酸含量达11.54%.分离鉴定出4种主要化学成分,羽扇豆醇(1)、异牡荆苷(2)、β-胡萝卜苷(3)、肥皂草苷(4).结论 鳄嘴花叶富含大量的人体必需氨基酸、微量元素及活性天然产物,具有较高的营养价值和药用价值.%Objective To analyze amino acids, trace elements and chemical constituents from the leaves of Clinacanthus nutans . Methods The amino acids and trace elements were detected by HPLC and ICP-OES, respectively. Chemical constituents were identified by the combination of column chromatography and spectral analysis. Results The leaves contained seventeen varieties of amino acids, eleven trace elements, and four primary chemical components. Conclusion The leaves are rich in amino acids, trace elements and bioactive chemical constituents, suggesting that Clinacanthus nutans is of high nutritional value.

  10. A Class of Graceful Trees

    Institute of Scientific and Technical Information of China (English)

    孟凡洪; 苏耕; 杨继

    2000-01-01

    The present paper shows the coordinates of a tree and its vertices, defines a kind of Trees with Odd-Number Radiant Type (TONRT), deals with the gracefulness of TONRT by using the edge-moving theorem, and uses graceful TONRT to construct another class of graceful trees.

  11. Distribution and relationships between selected chemical elements in green alga Enteromorpha sp. from the southern Baltic

    International Nuclear Information System (INIS)

    The concentrations of heavy metals (Cd, Cu, Ni, Pb, Zn and Mn) and macroelements (K, Na, Ca and Mg) were determined in green alga Enteromorpha sp. from the coastal zone of the southern Baltic including Gulf of Gdansk and Vistula Lagoon in 2000-2003. In order to estimate the degree of accumulation of each element by the green alga, concentration and discrimination factors (CFs) with respect to seawater were calculated. The results of factor analysis (FA) and ANOVA clearly indicate geographical differences between concentrations of chemical elements. Enteromorpha sp. from Vistula Lagoon and the southern Baltic exhibited higher levels of Mn and Ni, and Na and K, respectively. Anthropogenic impact of Cu, Pb and Zn, possibly originated from municipal sewage, was identified in alga samples collected in the Gulf of Gdansk, especially in the vicinity of Gdynia. From comparison our data with those published earlier results that Pb content in Enteromorpha sp. from the Gulf of Gdansk decreased within 1978-2003 reflecting reducing use of leaded petrol in Baltic countries in this period. The alga Enteromorpha sp. can be used for biomonitoring surveys of metal contaminants in coastal areas of the Baltic Sea. - Enteromorpha sp. can be used as efficient biomonitor for chemical elements in coastal areas of the Baltic Sea

  12. Distribution and relationships between selected chemical elements in green alga Enteromorpha sp. from the southern Baltic

    Energy Technology Data Exchange (ETDEWEB)

    Zbikowski, Radoslaw [Department of Food Sciences, Medical University of Gdansk, al. Gen. J Hallera 107, PL 80-416 Gdansk (Poland); Institute of Oceanography, University of Gdansk, Av. Pilsudskiego 46, PL 81-378 Gdynia (Poland); Szefer, Piotr [Department of Food Sciences, Medical University of Gdansk, al. Gen. J Hallera 107, PL 80-416 Gdansk (Poland)]. E-mail: pszef@amg.gda.pl; Latala, Adam [Institute of Oceanography, University of Gdansk, Av. Pilsudskiego 46, PL 81-378 Gdynia (Poland)

    2006-10-15

    The concentrations of heavy metals (Cd, Cu, Ni, Pb, Zn and Mn) and macroelements (K, Na, Ca and Mg) were determined in green alga Enteromorpha sp. from the coastal zone of the southern Baltic including Gulf of Gdansk and Vistula Lagoon in 2000-2003. In order to estimate the degree of accumulation of each element by the green alga, concentration and discrimination factors (CFs) with respect to seawater were calculated. The results of factor analysis (FA) and ANOVA clearly indicate geographical differences between concentrations of chemical elements. Enteromorpha sp. from Vistula Lagoon and the southern Baltic exhibited higher levels of Mn and Ni, and Na and K, respectively. Anthropogenic impact of Cu, Pb and Zn, possibly originated from municipal sewage, was identified in alga samples collected in the Gulf of Gdansk, especially in the vicinity of Gdynia. From comparison our data with those published earlier results that Pb content in Enteromorpha sp. from the Gulf of Gdansk decreased within 1978-2003 reflecting reducing use of leaded petrol in Baltic countries in this period. The alga Enteromorpha sp. can be used for biomonitoring surveys of metal contaminants in coastal areas of the Baltic Sea. - Enteromorpha sp. can be used as efficient biomonitor for chemical elements in coastal areas of the Baltic Sea.

  13. Optimization of class 2 tensegrity towers

    Science.gov (United States)

    Masic, Milenko; Skelton, Robert E.

    2004-07-01

    This paper concerns the optimal mass-to-stiffness ratio design of class-2 tensegrity towers. For different loading scenarios, the procedure seeks the topology and geometry of the structure that yields an optimal design satisfying common constraints. The domain of feasible tensegrity geometries is defined by imposing tensegrity equilibrium conditions on both unloaded and loaded structure. Remaining constraints include strength constraints for all elements of the structure and buckling constraints for bars. The symmetry of the design is imposed by restricting the domain of geometric variables and element parameters. The static response of the structure is computed by using a nonlinear large displacement model. The problem is cast in the form of a nonlinear program. The influence of material parameters on the optimal shape of the structure is investigated.

  14. Method for relating suspended-chemical concentrations to suspended-sediment particle-size classes in storm-water runoff

    Science.gov (United States)

    Rinella, Joseph F.; McKenzie, Stuart W.

    1982-01-01

    A method has been developed to relate suspended-chemical concentrations (associated with suspended sediments) in storm-water runoff to suspended-sediment particle-size classes. These classes are based on settling velocities in quiescent native water. This method requires processing 20 liters of water having a suspended-sediment concentration greater than 500 milligrams per liter. However, samples with suspended-sediment concentrations as low as 250 milligrams per liter may be analyzed, if sample volumes are increased to 50 liters. The time required for one person to separate suspended sediments into particle-size classes ranges from 6 to 14 hours. This report outlines procedures for processing metal, nutrient, and organic samples.

  15. Geochemistry of the Dissolved Load of the Changjiang Basin Rivers: Anthropogenic Impacts and Chemical Weathering, Evidences from Major Elements, Sr and B Isotopes

    Institute of Scientific and Technical Information of China (English)

    Benjamin Chetelat; LIU Cong-qiang

    2008-01-01

    @@ 1 Introduction Rivers provide a unique opportunity to have average information about chemical and physical erosion, about the major geochemical fractionations created by these major geological processes but also about the impact and disturbances of human activities on the Earth Engine.

  16. Design of Class-E Radio Frequency Power Amplifier

    OpenAIRE

    Al-Shahrani, Saad Mohammed

    2000-01-01

    Power amplifiers (PA) are typically the most power-consuming building blocks of RF transceivers. Therefore, the design of a high-efficiency radio frequency power amplifier is the most obvious solution to overcoming the battery lifetime limitation in the portable communication systems. A power amplifierà ­s classes (A, AB, B, C, F, E, etc), and design techniques (Load-pull and large-signal S-parameters techniques) are presented. The design accuracy of class-A power amplifier based on the s...

  17. Art of Class Teaching Encourage

    Institute of Scientific and Technical Information of China (English)

    HE Jiao-fei

    2013-01-01

    Teaching encourage can lead to student’s learning motivation and interesting. It improves the effect of classroom teach⁃ing. Methods of class teaching inspiration are: Target encourage, expectation encourage, emotional encourage, positive encourage, attribution encourage, competition encourage, caress encourage, democracy encourage, praise encourage, time encourage, check en⁃courage, questions encourage, examination encourage, score encourage, example encourage and understanding encourage.

  18. Element geochemistry of weathering profile of dolomitite and its implications for the average chemical composition of the upper-continental crust——Case studies from the Xinpu profile, northern Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    季宏兵; 欧阳自远; 王世杰; 周德全

    2000-01-01

    Geochemical behavior of chemical elements is studied in a dolomitite weathering profile in upland of karst terrain in northern Guizhou. Two stages can be recognized during the process of in situ weathering of dolomitite: the stage of sedentary accumulation of leaching residue of dolomitite and the stage of chemical weathering evolution of sedentary soil. Ni, Cr, Mo, W and Ti are the least mobile elements with reference to Al. The geochemical behavior of REE is similar to that observed in weathering of other types of rocks. Fractionation of REE is noticed during weathering, and the two layers of REE enrichments are thought to result from downward movement of the weathering front in response to changes in the environment. It is considered that the chemistry of the upper part of the profile, which was more intensively weathered, is representative of the mobile components of the upper curst at the time the dolomitite was formed, while the less weathered lower profile is chemically representative of the immo

  19. Tuneable microsecond-pulsed glow discharge design for the simultaneous acquisition of elemental and molecular chemical information using a time-of-flight mass spectrometer.

    Science.gov (United States)

    Solà-Vázquez, Auristela; Martín, Antonio; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2009-04-01

    A microsecond-pulsed direct current glow discharge (GD) was interfaced and synchronized to a time-of-flight mass spectrometer MS(TOF) for time-gated generation and detection of elemental, structural, and molecular ions. In this way, sequential collection of the mass spectra at different temporal regimes occurring during the GD pulse cycle is allowed. The capabilities of this setup were explored using bromochloromethane as model analyte. A simple GD chamber, developed in our laboratory and characterized by a low plasma volume minimizing dilution of the sample but showing great robustness to the entrance of organic compounds in the microsecond-pulsed plasma, has been used. An exhaustive analytical characterization of the GD-MS(TOF) prototype has been performed. Calibration curves for bromochloromethane observed at the different time regimes of the GD pulse cycle (that is, for elemental, fragment, and molecular ions from the analyte) showed very good linearity for the measurement of the different involved ions, with precisions in the range of 7-13% (relative standard deviation). Actual detection limits obtained for bromochloromethane were in the range of 1-3 microg/L for elements monitoring in the GD pulse "prepeak", in the range of 11-13 microg/L when monitoring analyte fragments in the plateau, and about 238 microg/L when measuring the molecular peak in the afterpeak regime. PMID:19256521

  20. 浅谈《化工工艺学》课程教学中和谐课堂的构建%Build Harmonious Class in the Teaching of Chemical Engineering Technology

    Institute of Scientific and Technical Information of China (English)

    左广玲; 叶红勇

    2012-01-01

    With the teaching reform of "Chemical Engineering Technology" as the Carrier,the paper explored how to Create equal teacher-student relationship,build harmonious teaching classes and improve teaching effect.Practice shows that build equal,harmonious and democratic teacher-student relationship,motivate the interest of learning and let students acquire knowledge in easy-going learning atmosphere can build harmonious classes and pursue the most effective learning and teaching.%以《化工工艺学》课程教学为载体,探索如何营造平等师生关系,构建和谐教学课堂,提高授课时效。实践表明:营造平等、和谐、民主的新型师生关系,激发学生学习兴趣,使学生在轻松的学习中获得知识,可以构建和谐课堂追求学习与教学的最大有效性。

  1. A Short History of Three Chemical Shifts

    Science.gov (United States)

    Nagaoka, Shin-ichi

    2007-01-01

    A short history of chemical shifts in nuclear magnetic resonance (NMR), electron spectroscopy for chemical analysis (ESCA) and Mossbauer spectroscopy, which are useful for chemical studies, is described. The term chemical shift is shown to have originated in the mistaken assumption that nuclei of a given element would all undergo resonance at the…

  2. On the Geometry of the Periodic Table of Elements

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2010-10-01

    Full Text Available The presented analytical research manifests a geometrical connexion existing among the elements of the Periodic Table of Elements, in addition to the known physical chemical connexion.

  3. Reconstruction of the diet of a pre hispanic population sector of Cuauhnahuac, Morelos by means of the chemical elements analysis in skeletal rests

    International Nuclear Information System (INIS)

    The goal of this work was diet reconstruction of 25 pre hispanic residents of Cuauhnahuac, tributary town of the mexicas, during the Late Pos classic period (1350-1521 a.C.). The analysis included human skull samples proceeding from human femur, tibia and fibula. The applied technique was X-ray fluorescence spectrometry (XRF) to know the mineral concentrations, which are closely related with the quality and quantity of the consumed food. The main indicative elements are strontium (Sr), that denotes the consumption of vegetables, zinc (Zn), that shows the consumption of animal proteins, and magnesium (Mg), associated with Meso american food resources. The results indicate the existence of differences in the diet among the same population's individuals, probably because social stratification determined the power resources acquisition. (Author) 28 refs., 7 tabs., 2 figs

  4. Frontiers of heavy element nuclear and radiochemistry

    International Nuclear Information System (INIS)

    The production and half-lives of the heaviest chemical elements, now known through Z = 112, are reviewed. Recent experimental evidence for the stabilization of heavy element isotopes due to proximity to deformed nuclear shells at Z = 108 and N = 162 is compared with the theoretical predictions. The possible existence of isotopes of elements 107--110 with half-lives of seconds or longer, and production reactions and experimental techniques for increasing the overall yields of such isotopes in order to study both their nuclear and chemical properties are discussed. The present status of studies of the chemical properties of Rf, Ha, and Sg is briefly summarized and prospects for extending chemical studies beyond Sg are considered

  5. Chemical composition and acidity of size-fractionated inorganic aerosols of 2013-14 winter haze in Shanghai and associated health risk of toxic elements

    Science.gov (United States)

    Behera, Sailesh N.; Cheng, Jinping; Huang, Xian; Zhu, Qiongyu; Liu, Ping; Balasubramanian, Rajasekhar

    2015-12-01

    The severe winter haze episode that occurred in Shanghai from December 2013 to January 2014, characterized by elevated levels of particulate matter (PM), received considerable international attention because of its impacts on public health and disruption of day-to-day activities. To examine the characteristics of PM during this haze episode and to assess the chemistry behind formation of secondary inorganic aerosols (SIA) and associated health impacts due to exposure of toxic elements, we characterized eight water soluble inorganic (WSI) ions and twenty four trace elements in twelve size-fractionated PM (10 nm-9.9 μm). The average mass concentrations of coarse (1.8 μm events increased significantly (P < 0.05) to 69 ± 18 × 10-6 compared to non-hazy days (34 ± 10 × 10-6). The qualitative source attribution analysis suggested that the occurrence of haze could be due to a combination of increased emissions of PM from multiple anthropogenic sources followed by its accumulation under unfavourable meteorological conditions with lower mixing heights and less wind speeds and the formation of secondary aerosols.

  6. Cyclic subgroups in class groups of real quadratic fields

    International Nuclear Information System (INIS)

    While examining the class numbers of the real quadratic field Q(√n2 + 3n + 9), we observed that the class number is often a multiple of 3. There is a simple explanation for this, namely -27 = (2n + 3)2 - 4(n2 + 3n + 9), so the cubes of the prime ideals above 3 are principal. If the prime ideals themselves are non-principal then 3 must divide the class number. In the present paper, we study this idea from a couple different directions. In the first section we present a criterion that allows us to show that the ideal class group of a real quadratic field has a cyclic subgroup of a given order n. We then give several families of fields to which this criterion applies, hence in which the ideal class groups contain elements of order n. In the second section, we discuss the situation where there is only a potential element of order p (=an odd prime) in the class group, such as the situation described above. We present a modification of the Cohen-Lenstra heuristics for the probability that in this situation the class number is actually a multiple of p. We also extend this idea to predict how often the potential element of order p is actually non-trivial. Both of these predictions agree fairly well with the numerical data. (author). 14 refs, 2 tabs

  7. Chemistry of the transactinide elements

    International Nuclear Information System (INIS)

    Synthesis and decay of elements in the upper end of periodic table (z=104 to 111) are described. In view of very short half-life of about 1 s, the production of the transactinide isotopes and their transport to the separation and detection chamber are to be necessarily carried out employing fast and reliable techniques. Advances in microchemical separation techniques such as OLGA-II, HEVI, ARCA-II and SISAK, coupled to sensitive detection methods enable the detection of these heavier transactinide elements at atomic level. Their position in the periodic table and similarities, if any, with the corresponding lighter homologs are discussed based on their predicted and observed chemical behaviour. (author). 70 refs., 15 figs

  8. Statistic analysis of grouping in evaluation of the behavior of stable chemical elements and physical-chemical parameters in effluent from uranium mining; Analise de agrupamento na avaliacao do comportamento de elementos quimicos estaveis e parametros fisico-quimicos em efluente de mineracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de S., E-mail: wspereira@inb.gov.br, E-mail: pereirarsj@gmail.com [Universidade Federal Fluminense (GETA/LARARA-PLS/UFF), Niteroi, RJ (Brazil). Grupo de Estudos em Temas Ambientais. Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos; Py Junior, Delcy de A.; Dores, Luis A. de C.B.; Campelo, Emanuele L.C.; Morais, Gustavo F. de; Kelecom, Alphonse, E-mail: delcy@inb.gov.br, E-mail: kclecom@uol.com.br [lndustrias Nucleares do Brasil (UTM/INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Pereira, Juliana R. de S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil)

    2013-10-01

    The Ore Treatment Unit (UTM) is a uranium mine off. The statistical analysis of clustering was used to evaluate the behavior of stable chemical elements and physico-chemical variables in their effluents. The use of cluster analysis proved effective in the evaluation, allowing to identify groups of chemical elements in physico-chemical variables and group analyzes (element and variables ). As a result, we can say, based on the analysis of the data, a strong link between Ca and Mg and between Al and TR{sub 2}O{sub 3} (rare earth oxides) in the UTM effluents. The SO{sub 4} was also identified as strongly linked to total solids and dissolved and these linked to electrical conductivity. Other associations existed, but were not as strongly linked. Additional collections for seasonal evaluation are required so that assessments can be confirmed. Additional statistics analysis (ordination techniques) should be used to help identify the origins of the groups identified in this analysis. (author)

  9. Elements of linear space

    CERN Document Server

    Amir-Moez, A R; Sneddon, I N

    1962-01-01

    Elements of Linear Space is a detailed treatment of the elements of linear spaces, including real spaces with no more than three dimensions and complex n-dimensional spaces. The geometry of conic sections and quadric surfaces is considered, along with algebraic structures, especially vector spaces and transformations. Problems drawn from various branches of geometry are given.Comprised of 12 chapters, this volume begins with an introduction to real Euclidean space, followed by a discussion on linear transformations and matrices. The addition and multiplication of transformations and matrices a

  10. Elements of deductive logic

    OpenAIRE

    Eagle, Antony

    2008-01-01

    A textbook for an 'advanced introductory' logic class (I used it as a textbook for mathematically capable introductory logic students). The book uses the tableau method, and includes standard results up to a proof of the soundness of predicate logic. Its slightly unusual features include a slightly greater emphasis on decidability than is usual, some discussion of philosophical issues, and more obviously, the presentation of a free logic as standard, alongside a classical alternative.

  11. Student versus Faculty Perceptions of Missing Class.

    Science.gov (United States)

    Sleigh, Merry J.; Ritzer, Darren R.; Casey, Michael B.

    2002-01-01

    Examines and compares student and faculty attitudes towards students missing classes and class attendance. Surveys undergraduate students (n=231) in lower and upper level psychology courses and psychology faculty. Reports that students found more reasons acceptable for missing classes and that the amount of in-class material on the examinations…

  12. A unified architecture of transcriptional regulatory elements

    DEFF Research Database (Denmark)

    Andersson, Robin; Sandelin, Albin Gustav; Danko, Charles G.

    2015-01-01

    Gene expression is precisely controlled in time and space through the integration of signals that act at gene promoters and gene-distal enhancers. Classically, promoters and enhancers are considered separate classes of regulatory elements, often distinguished by histone modifications. However, re...

  13. Research plans of heavy element nuclear chemistry in JAERI

    International Nuclear Information System (INIS)

    Research in nuclear chemistry of heavy elements in JAERI is briefly introduced. Status and future prospects for studies of chemical and nuclear properties of the transactinide elements with the JAERI tandem accelerator are presented. (author)

  14. Stochastic prediction of drought class transitions

    OpenAIRE

    Paulo, Ana A.; L. S. Pereira

    2008-01-01

    This paper aims at the stochastic characterization of droughts applying Markov chains modeling to drought class transitions derived from SPI time series. Several sites in Southern Portugal having updated data on precipitation available were considered. The drought class probabilities, the expected residence time in each class of severity, the expected time for the transition between drought classes and the drought severity class predictions 1, 2, or 3 months ahead have been obt...

  15. Classifying chemical elements and particles: from the atomic to the sub-atomic world

    OpenAIRE

    Kibler, Maurice

    2003-01-01

    published in the book "The Periodic Table: Into the 21st Century", edited by D.H. Rouvray and R.B. King (Research Studies Press, Baldock, UK, 2004) pp. 297-329. This paper presents two facets. First, we show that the periodic table of chemical elements can be described, understood and modified (as far as its format is concerned) on the basis of group theory and more specifically by using the group SO(4,2)xSU(2). Second, we show that "periodic tables" also exist in the sub-atomic and sub-nu...

  16. Classes of almost clean rings

    OpenAIRE

    Akalan, Evrim; Vas, Lia

    2013-01-01

    A ring is clean (almost clean) if each of its elements is the sum of a unit (regular element) and an idempotent. A module is clean (almost clean) if its endomorphism ring is clean (almost clean). We show that every quasi-continuous and nonsingular module is almost clean and that every right CS and right nonsingular ring is almost clean. As a corollary, all right strongly semihereditary rings, including finite $AW^*$-algebras and noetherian Leavitt path algebras in particular, are almost clean...

  17. Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation - Part 2: Alkaline earth elements as tracers of watershed hydrochemistry and provenance

    Science.gov (United States)

    Brügmann, G.; Krause, J.; Brachert, T. C.; Stoll, B.; Weis, U.; Kullmer, O.; Ssemmanda, I.; Mertz, D. F.

    2012-03-01

    For reconstructing environmental change in terrestrial realms the geochemistry of fossil bioapatite in bones and teeth is among the most promising applications. This study demonstrates that alkaline earth elements in enamel of Hippopotamids, in particular Ba and Sr are tracers for water provenance and hydrochemistry. The studied specimens are molar teeth from Hippopotamids found in modern and fossil lacustrine settings of the Western Branch of the East African Rift system (Lake Kikorongo, Lake Albert, and Lake Malawi) and from modern fluvial environments of the Nile River. Concentrations in enamel vary by ca. two orders of magnitude for Ba (120-9336 μg g-1) as well as for Sr (9-2150 μg g-1). Concentration variations in enamel are partly induced during post-mortem alteration and during amelogenesis, but the major contribution originates from the variable water chemistry in the habitats of the Hippopotamids which is dominated by the lithologies and weathering processes in the watershed areas. Amelogenesis causes a distinct distribution of Ba and Sr in modern and fossil enamel, in that element concentrations increase along profiles from the outer rim towards the enamel-dentin junction by a factor of 1.3-1.5. These elements are well correlated with MgO and Na2O in single specimens, thus suggesting that their distribution is determined by a common, single process. Presuming that the shape of the tooth is established at the end of the secretion process and apatite composition is in equilibrium with the enamel fluid, the maturation process can be modeled by closed system Rayleigh crystallization. Enamel from many Hippopotamid specimens has Sr/Ca and Ba/Ca which are typical for herbivores, but the compositions extend well into the levels of plants and carnivores. Within enamel from single specimens these element ratios covary and provide a specific fingerprint of the Hippopotamid habitat. All specimens together, however, define subparallel trends with different Ba

  18. Diverse in- and output polarities and high complexity of local synaptic and nonsynaptic signalling within a chemically defined class of peptidergic Drosophila neurons

    Science.gov (United States)

    Peptidergic neurons are not easily integrated into current connectomics concepts, since their peptide messages can be distributed via non-synaptic paracrine signaling or even via volume transmission. Moreover, and especially in insects, the polarity of peptidergic interneurons in terms of in- and o...